SAN FRANCISCO PUBLIC LIBRARY 3 1223 06899 1570 ENVIRONMENTAL EFFECTS OF DREDGING & DISPOSAL IN THE SAN FRANCISCO BAY ESTUARINE SYSTEM JANUARY 1978 I SPECIAL STUDIES PROJECT FOR REF 614. 77 D63e ASSOCIATION OF BAY AREA GOVERNMENTS OABAG ENVIRONMENTAL MANAGEMENT PROGRAM PREPARED RY: LOUIS H.DISALVO APR 2 8 1978 DOCUMENTS OCPT 8.F. PU UG LIBRARY San Francisco Public Library Government Information Center San Francisco Public Library 100 Larkin Street, 5th Floor 5an Francisco, CA 94102 REFERENCE BOOK Not to be taken from the Library ENVIRONMENTAL EFFECTS OF DREDGING AND DISPOSAL IN THE SAN FRANCISCO BAY ESTUARINE SYSTEM a report to The Association of Bay Area Governments Hotel Claremont Berkeley, California 94705 Louis H. DiSalvo, Ph.D. Marine Science Consultant 315 Melven Court San Leandro, CA 94577 Cover Design by Pat Wong Digitized by the Internet Archive in 2014 http://archive.org/details/environmentaleff1978disa TABLE OF CONTENTS PAGE STATEMENT OF PROBLEM 1 INTRODUCTION 4 SECTION I: BASIC CHARACTERISTICS 5 Structure and Water Circulation 5 Sediments 9 Chemical Processes 13 Biology 16 Dredging 18 SECTION II: ENVIRONMENTAL IMPACTS 23 Direct Effects 24 Indirect Effects 29 SECTION II: REGULATION OF DREDGING 37 CONCLUSIONS 41 RECOMMENDATIONS 43 LITERATURE CITED 44 APPENDIX A 48 APPENDIX B 52 3 1223 06899 1570 STATEMENT OF PROBLEM "Dredge Rules Pose Disaster" SF Examiner, Oct. 27, 1972 "A Witches Brew of Waste" SF Examiner, Feb. 4, 1973 "Tougher New Dredging Controls Win Support" SF Examiner, March 22, 1972 "Bay Dredging Controls Held Too Expensive" SF Examiner, March 21, 1972 "Army Bests Navy in Dredging Dispute" SF Examiner, Jan. 28, 1972 The preceding are but a small sample of the headlines which have described the often strident controversies which have developed over the conduct of dredging, and disposal of dredged material in the San Francisco Bay estu- arine system. On the wave of environmental activity of the 1960 's and 70' s, many people came to the realization that they lived near the shores of a valuable environmental resource. They carried out significant political actions which resulted in legislation to stop the filling of the Bay and to control development around its shores. Nationwide, environmental awareness led to a call for more stringent environment protective legislation, cul- minating in passage of a number of Acts of Congress including the Federal Water Pollution Control Act, The National Environmental Policy Act, and the Marine Research, Protection and Sanctuaries Act, among others. With these laws, Congress, representing the people, began a long and tedious process aimed at controlling activities deleterious to the environment, including the unregulated disposal of dredged material in the nation's waterways. As the newspaper articles suggest, people became aware indirectly that es- tuaries are natural sediment traps, and that San Francisco Bay was indeed trapping large quantities of wastes within its sediments. These sediments inconveniently settle out in quiet areas of the Bay blocking harbors and waterways of commercial, military and recreational importance. Indirectly, the Army Corps of Engineers, which is normally charged with the responsi- bility of maintaining the waterways, became involved with wastes discharged into the Bay. The discovery that the Bay dredged material was sometimes highly contaminated was a finding repeated for a number of the nation's es- tuaries. National impetus was given to evaluation of problems, development of reasonable rules and regulations for the disposal of dredged materials, and far reaching planning efforts to stop contamination of the estuarine sediments at the source. -1- This report summarizes some aspects of the problem as it currently stands for the San Francisco Bay system, with a resume of current research begun several years ago in response to public demands. Emotionally charged debate has at least been supplemented with a resolve to obtain reliable scientific information upon which to base environmental management deci- sions. Unfortunately, the basic nature of scientific research is that it is slow and costly, and that answers are not generated as quickly as some would like. It can only be hoped that as future disputes arise, the available and emerging scientific information concerning the ecological impacts of dredging and disposal will be taken into account by adminis- trators, regulatory bodies, expert witnesses, and perhaps even the judges who may need to make critical rulings. However, since there is substan- tial academic debate in some areas related to dredging and disposal is- sues, the mere existence of selected bodies of scientific data does not guarantee resolution of an issue. Since the Bay system undergoes multi- ple usage by various segments of society, it is of paramount importance to realize that ultimate decisions concerning dredging and disposal will be based on economic, social, and political realities, as well as knowl- edge of the Bay system. -2- ACKNOWLEDGMENTS I wish to thank my colleague, Dr. Harold Guard, and research associates Ms. Nina Hirsch and Mr. Robert Simon, for aiding in various phases of the develop- ment of this report. Special thanks are extended to the files section of the San Francisco Examiner, the library of the San Francisco District Army Corps of Engineers, the Water Resources Library of the University of California at Berkeley, and the Naval Facilities Engineering Command, 12th Naval District, for their assistance. I further thank the experts in various disciplines, particularly the members of the ABAG Special Studies Technical Advisory Committee for constructive sug- gestions rendered in the development of this study. -3- INTRODUCTION This study is an attempt to evaluate the current state of knowledge on the effects of dredging and disposal practices in the San Francisco Bay estuarine system. Estuarine processes are in general complicated, and those of the San Francisco Bay system particularly so, which render comparison with other estuaries difficult. The first section of this report presents some general characteristics of the system in simplified terms, and discusses general aspects of dredging and disposal. Readers familiar with these topics are asked to refer to other references for more detailed discussions (2,3,4,5). The second section of this report is devoted to discussions of recent research on potential deleterious effects of dredging and disposal in the Bay system, with some relevant inputs from the general literature. Readers who desire greater detail should refer to the references re- viewed, as these without fail contain extensive literature surveys in each area. Broad literature surveys in these fields would have at least doubled the size of this report. The diversity of estuaries and nature of the different sources of wastes on their margins have generated a diverse body of literature on the effects of dredging and disposal in different esturine systems. In most cases, literature is so site-specific that there is little rationale for attempting to transfer systems-wide interpretations of effects. There are, never- theless, comparisons which may be made between all basic processes, such as the fundamental chemistry of sediment-metal interaction. The third section of the report has been devoted to a summary of the regulation of dredging, its basis, and current trends in regulatory criteria. This is a fast-moving field, for which much new information has recently been made available. Environmental concern at both na- tional and state levels has resulted in a body of legislation which has been employed in preventing overt environmental impacts, partic- ularly from filling activities. Enforcement of the legislation is undergoing an evolutionary process as new research results are made available and translated into regulatory criteria. Numerous Federal and State agencies affect the granting of dredging and disposal per- mits for the Bay. Some agencies have direct permitting power, while others have commenting functions which carry great weight in final permit decisions. The data base from which sound disposal practices may be determined is not complete, although interim guidelines are now available. Emerging scientific data are beginning to suggest that a number of presently used guidelines for the evaluation of contamination of dredged material are probably too restrictive. SECTION I BASIC CHARACTERISTICS Structure and Water Circulation The San Francisco Bay estuary, following the definition of Pritchard (1), is a semi -enclosed body of water which has free connection with the sea (Golden Gate), and within which the seawater is measurably diluted with freshwater derived from land drainage, primarily the Sacramento and San Joaquin Rivers. Geologically, the form of the Bay system was produced by tectonic processes in which movements of the earth's crust downfaulted the bay basin and uplifted the surrounding hills. The original surface area of the Bay systems was probably about 2038 sq km (prior to 1850). It is estimated that there were originally about 800 sq km of marshland surrounding different parts of the bay, although today, fewer than 325 sq km of marsh remain (2). Since 1850, over 600 sq km (30%) of Bay mudflat and marshland have been converted for salt production, agriculture, industry, recreation waste disposal, transportation, and military use. The present Bay system includes four major sub-bays as illustrated in Figure 1. Perhaps the most striking feature of the estuary is that the single opening to the sea, the Golden Gate, is only one mile wide This is in contrast to drowned river valley estuarines on the East Coast (e.g., Chesapeake Bay, Delaware Bay) which have broad openings to the sea many miles across. The Golden Gate opens to the Central Bay, followed by the South Bay to the south and San Pablo Bay to the north. The final embayment, Suisun Bay, to the northeast, is con- nected to San Pablo Bay by another deep channel, the Carquinez Strait Bathymetry of the Bay is shown in Figure 1. Freshwater flows into Suisun Bay through the complex inland delta formed by the Sacramento and San Joaquin Rivers, at a rate dependent on the annual rainfall in the drainage basin of the rivers. In recent years freshwater inflow has been reduced by removal of freshwater transferred to Southern California (see Special Study, Delta Outflow). "The net delta inflow is complicated by tidal action, but it is estimated to be about 16.8 million acre-ft. per year (57,000 cfs) under present upstream develop- ment conditions. Historically, without any flow reg- ulation or diversion, Delta input was estimated to be 30.3 million acre-ft. per year." (3) In years of normal freshwater runoff, Suisun Bay is composed mainly of freshwater; the first major mixing zone where seawater meets fresh water is in San Pablo Bay, although in dry years, reduced flow of freshwater allows intrusion of salt-water into Suisun Bay. Table 1 lists a number of water quality characteristics for the different em- bayments as reported by the University of California SERL study (4). -5- TABLE 1. SUMMARY OF WATER QUALITY CHARACTERISTICS OBSERVED IN SAN FRANCISCO BAY Partimet'.'i- Unit South Bay L.-ve r fv.y M rtti !»iy Temperature C a low mean high* 9-3 J." • j 2« .0 10-7 it .8 21 .0 10. 1 19-0 11 -5 l-'t • 1 17. 6 Oecchi disc transparency ft low mean high 0.5 1 o i -y I..0 0.5 ? • J 6.5 1.0 -> • 6 9.0 1-5 5 .9. 6-5 pH lov mean high !■?. R.O 7-8 7 8.1 7.6 7.9 8.1 7-5 7.85 8.0 Suspended solid.?. me/ 1 low mean high 15 8 56 5 36 6 21 57 Chloroslty 3/* low high 9-5 J- > 19 13-5 16 17 15-5 18 10 16 13 Dissolved oxygen low high 0.7 5 ■ 1 8-5 7-0 7.I1 8.5 6.5 7-5 3.2 6.2 7- 4 8- 5 Dissolved oxygen saturation p low mean high 9,5 55 92 81 90 99 80 8lt 92 75 85 96 Biochemical oxygen demand KS>lt ".9M Nitfute nltro*4<*n m.j f 9 low high O.O'j * • j j i.i 0.08 0. 3I4 0.55 0.16 0.36 <>. iP 'i.?5 O.38 RcActive phosphate low high 0-5 0.5 0.8 0.2 0.32 Q.k 0.2 0.2 ' O.U Dissolved silica voe/t low mean high 2-3 8.7 16 2-9 7.7 l.lt 3-6 5-5 2-5 u'.B 6.8 Coliform bacteria MPJ.'/lOO n/ low mean high 10 2 x 10* 3 x 10s 10 5 x 1C? 5 x 10* 2.00 1 x 103 6 x 10* 200 5 x 10* 1 x 10* Total microplar.kton ceils/f low mean high 1.2 X 103 l.i, x 10* 3.S x 105 3.0 x 103 1.0 x 10* 1.5 * iO6 * ' x 13s 5.7 y 104 £.7 / :o« -.-. x l.O3 './' .< 10* 5 . . x 10' Total zoopianJcton crg/cu r, low mean high 500 7,000 40,000 5,100 3,000 5,800 1 7,6y. 12,00-; j 15,000 1,000 £ . ooo ;.j,ooo 3a n rtibli Bny h«y 1 8.3 6-9 1 ** -9 1 5 • r> 21 ■ 5 i 0.5 1 »o J ' ? 7.2 7 61, 7 e=; 7 O 1 -7 13 Jit "»? W 1 12 3.5 0.02 10. s 2 ■ 5 16 8.5 6.8 6.6 8.0 8.1. 1 9.^ I 10.2 80 65 85 85 92 9lt 0.1 O.lt 0.8 1 . 1 1.4 0.1 0.06 0.01 0.1 c, 0 . J 5 1 0.2'J 0.03 O.'J'i 0.35 0. ',1 1.0 0.0', 0.2 0.1 0.30 0.20 O.U 0.5 1.4 1.5 6.8 13.6 lit 30 20 700 1 x 103 ' x ">3 1 x 10* 2 x 10* .0 x r,3 4 .6 / 10* 1 .7 x 104 J.C x 10'- ! 300 10,000 sa,ooo y/j 5,000 15,000 low = 5 percentile value, ^igh - 95 percentile -value. (from Ref. 4) -7- Aside from geological origins, estuaries are often classified on the basis of their characteristic water circulation and the ways in which seawater meets and mixes (or does not mix) with the freshwater inflow. Water movement in estuaries is governed primarily by tidal action and freshwater inflow. These forces are modified by the action of the wind and density currents which are usually of low magnitude but still of importance in all discussions of estuarine water movement. Cir- culation is further modified by the configuration of the "walls" of the estuary, including the shape of its shoreline, bathymetry (depth profile), and the presence of islands and peninsulas. Drowned river valleys, such as Delaware Bay, have comparatively well-defined water flows based on their linear shape. The multiple embayments of the San Francisco Bay system produces complicated circulation patterns. The volume of the Bay is approximately 6.7 x 10^ cubic meters (5). Approximately 24% of this volume is moved in and out of the Golden Gate on an average tidal exchange (5). This shows the extremely large forces at work when considering the tide as a force in water movement. The tides in the Bay system are primarily semi-diurnal (two highs and two lows daily), which create strong currents in the channels ranging from 225 cm per sec (4.2 knots) at the Golden Gate to 100 cm per sec (1.8 knots) at the extreme end of the South Bay. A second force driving water movements in the Bay is that of the prevailing summer winds and sporadic winter storms. These winds create non-tidal water flows amounting to a small percentage of the wind speed (5). This circulation is effective primarily in the Bay shallows. A third force in water movement is the mass flow of freshwater into the Northern Bay through Suisun Bay and the Carquinez Strait into San Pablo Bay. "More than 90% of the mean annual river discharge (840 m3 per sec) entering the Bay is contributed to the northern reach by the combined flows of the Sacramento and San Joaquin Rivers; the re- maining 10% is contributed by small tributary streams and sewage inflow." (5) This force is dissipated in the upper reaches of the Bay. Freshwater river inflow is lighter per unit volume than seawater and thus tends to flow out on top of seawater, particularly when other mixing forces in an estuary are weak. This separation of waters is known as stratification. In the San Francisco system, this phe- nomenon occurs mainly in the upper reaches of San Pablo Bay and in Suisun Bay. Tidal and wind-driven currents tend to mix fresh and salt-water in the lower reaches of the Bay. In general, the greater the river flow, the greater degree of stratification that can be expected. -8- "For low freshwater inflows (140-280 nr/sec) all portions of the Bay system are considered well mixed; for inflows 2830 m3/sec, the Golden Gate and extreme South Bay areas remain well mixed, but mid-South Bay, San Pablo Straint, and Carquinez Strait change to a partially mixed condition. In the area above Carquinez Strait, the flow is highly stratified. For an inflow of 5660 rrvVsec (note: extremely wet year), there is no evidence of well mixed conditions anywhere in the system." (2) Stratification of estuarine water produces a fourth major movement of water known as density current, or "non-tidal drift" (5). In San Francisco Bay, non- tidal drift is a current set near the bottom, run- ning northward up San Pablo Bay and into Suisun Bay and may show speeds as high as 10 cm per sec. The region where non-tidal drift up the Bay is counterbalanced by the magnitude of river flow is known as null zone. This zone may migrate northward or southward in the system depending on the magnitude of river runoff in any given year (6). In summary, the four major embayments shown in Figure 1 constitute four (interconnected) functional subsystems of the estuary, each with dif- fering major characteristics of bathymetry, salinity distribution, and water movement. The South Bay is generally shallow and rarely has a major influx of tributary water. It is a high salinity lagoon with both tide and wind effects important. The Central Bay is deep, domi- nated by tides and rarely stratified. San Pablo Bay is shallow, often stratified and affected strongly by both wind and tides. Suisun Bay is moderately shallow, often highly stratified, and highly affected by river flow, with less influence from tides and wind. Although much work has been done, no predictive models are as yet available for water circulation throughout the Bay system. Sediments and Sedimentary Processes The preceding section has provided a broad view of the complex factors governing water movement in the Bay. Water movements dominate the sedimentary processes in the Bay, which, in turn, govern the needs for dredging and mediate the effects of aquatic disposal of dredged mate- rials. Sediments are aquatic soils commonly known as muds and sands. Sedi- ments result from soil erosion and washing of mineral and organic matter from the drainage basin into rivers, by which they are carried in suspension or dragged along the bottom (bedload) until they reach estuarine or ocean waters. The parent rock substrate of the Bay system (Franciscan formation) is overlain with hundreds of feet of sediments deposited since the geological origin of the Bay. Sediments are categorized on the basis of particle size as shown in Figure 2. Sedimentary particles common in estuaries include micro- scopic colloidal particles, clays, silts, with minor amounts of sand. -9- Scales Wemworth (1922) after Udden (1898) c Boulder Cobble " 1 -« ' -B ' Pebble -4 -2 -1" 0 ; ' +2 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 Colloid Granule Very coarse Coarse Medium Fine Very fine Coarse Medium Pine Very fine Coarse Medium Fine Very fine U S. Bureau of . Sotte . - i •«;■. f 1 IRKS 5 i 31.3 1 1.9S 0.49 0.24 Clay FIGURE 2. Classification of sediment particle size according to standard Wentworth grain-size for sediments. -10- In addition to terrigenous (land derived) matter, sediments contain small fractions of organic and inorganic matter derived from plants and animals living in the estuary. The stronger the river or esturine current velocity, the larger size and number of particles that can be carried in the water column. Conversely, where water flow decreases, particles drop out of suspension and settle to the bottom. Sediments are sorted by water movement, with the larger sized particles (sand and gravel ) coming to rest in deeper, high velocity channels. For ex- ample, San Francisco Bar sediments are well-sorted sands. The deep channels, including the Golden Gate, are floored with sand and gravel. Because of their physiography, patterns of water movement, and physi- cal-chemical properties of the water, it is generally recognized that estuaries act as sediment traps. Normal sedimentary processes can be expected to completely fill San Francisco Bay in a few thousand years. Where freshwater mixes with salt-water, finely particulate sediments, normally unable to settle out by gravity, undergo an electrochemical process called aggregation. In this process, fine particulates join to form clusters which are significantly heavier than water and thus settle in the water column. As these clusters reach the bottom of a basin, they may interfere with each other's settlement (hindered settlement) and form a light sediment-water suspension termed a floe or fluff." As this suspension loses water, it is termed fluid mud. As the fluid mud approaches 400 g sediment per liter of water, it fails to flow and bottom deposition can occur. With time, settled sediments may become compacted due to the influence of gravity, lose water from between sediment particles, and become consolidated. At any point in this sequence, strong physical forces can resuspend sediments and disperse them back into the water column, and the en- tire settling process may recur. Such strong forces include tidal currents, wind waves, and dredging and disposal of sediments. Sediments arriving in San Francisco Bay are primarily soil erosion products from its drainage area (7). About 81 percent of these sedi- ments arrive at the Carquinez Strait from the Central Valley. The remainder of the sediments arise from local tributary drainage (7). The sediments consist primarily of clays (60 percent), silts (30 percent), and fine sands (10 percent). A majority of the sediments are transported during typically strong river flows in winter months. The CE estimate of quantitative sediment budgets in the Bay system are presented in Figure 3. In this model, sediment not lost to the ocean or land disposal is deposited in the Bay system. Part of the volume occupied by these sediments is compensated for by the mean annual rise in sea level and by geological subsidence (sinking), particularly in the South Bay. There is no question that sediments are trapped within the Bay system, but the state of the art is such that there is continued debate as to the quantity retained. Conomos1 conceptual model (5) suggests significantly more retention of sediments in the Bay than does the CE. He suggests that sedi- ment lost to the ocean is only 6 percent yearly compared to CE es- timates of 50-70 percent. -11- ANNUAL DEPOSITION RESERVOIR (HYDRAULIC MINING) 1.5 B (historical inflow from Sierra, stored in San Pablo B. RESERVOIR 14.5 B (basin sediments) Mr MILLION B r BILLION FIGURE 3. Sediment movement (in cubic yards) in San Francisco Bay (from Ref. 3). -12- The CE suggests that sediments flowing into the Bay in winter season are spread throughout the Bay and deposited in the shallows and mud flat areas. With the advent of summer winds, these sediments are re- suspended, moved with water circulation, and redeposited in deeper regions unaffected by wind driven turbulence and strong tidal currents Quantities of these suspended sediments are transported to sea with tidal currents, and significant amounts settle in the relatively un- distributed dredged channels and harbors. Conomos (5) suggests that during the winter, a majority of the sediments coming through the Carquinez Strait are trapped in the shallows of the null zone (San Pablo Bay), and with the advent of summer, winds resuspend sediments, and the null zone migrates into Suisun Bay where large amounts of sediments are deposited. Whatever the eventual resolution of this debate, the fact remains that filling up of dredged shipping channels (shoaling) occurs at different rates in different years. An irregular schedule of dredging is re- quired on most projects based on depth measurements made routinely by the CE and facilities users. Mare Island Strait Channel shoals rap- idly, based on its calm nature and proximity to the null zone where sediments are concentrated in the water column. Approximately 2 mil- lion cubic yards of sediment are normally removed from this site on a twice-annual schedule, making it the most heavily dredge site in the Bay. However, in the initial dredging period of 1977, less than one- tenth the normal amount of sediment was removed from this site due to prevailing drought conditions with concomitant weak river flows which failed to deposit a normal winter sediment load. San Pablo Bay contains a reservoir of about 1.5 billion cubic yards of sediment washed from gold diggings in the Sierra foothils between 1848 and 1884 (14). This sediment decreased the average depth of this embayment by 5 feet. Chemical Process Salinity distribution in the Bay system (see "chlorosi ty" , Table 1), in addition to producing density currents, exerts numerous chemical effects. Perhaps the most important of these is causation of parti- cle aggregation as mentioned above. Only 1-2 parts per thousand of sea salt are required to cause minute sedimentary particles to aggre- gate. The presence of salt in the water has a marked effect on the distribution of organisms of estuaries, as some species are more tolerant to salt than others. Estuaries unaffected by man are usually rich in both inorganic nu- trients (nitrogen, phosphorus, trace elements) and organic nutrients (detritus) derived from biological production upstream of the estuary and within highly productive margins of the estuary such as the salt marshes. Ammonium nitrogen and orthophosphate are routinely found in high concentrations in interstitial waters of most estuarine sediments These materials are released into the water column during sediment disturbance. Ammonium nitrogen is related to the kjeldahl nitrogen -13- content of the sediment. Orthophosphate is controlled by the iron con- tent of the sediment, as this nutrient is co-precipitated upon forma- tion of iron hydroxides when iron in (anoxic) sedimentary interstitial waters is released into oxygenated waters. In San Francisco Bay, the large amount of iron in the sediments probably results in rapid capture of orthophosphate which might otherwise be released during a dredging operation. Ammonia release may be a significant occurrence during dredging. Dynamics of plant nutrients are covered in the ABAG Special Study, Eutrophication in San Francisco Bay (1978). The San Francisco Bay estuary, like most of the nation's large estu- aries, is a "septic tank of the megalopolis" as described by DeFalco (9). The San Francisco Bay system receives flows of wastes from over 5 million people as summarized in a study completed in 1964 (Table 2). Projections for the Bay into 1980 (10) predict increases in or- ganic waste inflows as growth of the population and expansion of the economic base is expected to offset gains realized by the new con- struction of waste treatment facilities. With regard to dredging problems, it is well known that finely partic- ulate sediments are able to scavenge pollutant heavy metals , pesticides, and oil pollutants from the water column and carry them into the bottom sediments. The dredging of polluted sediments has raised questions concerning the possible impact of these materials on the Bay biota, as many of the waste compounds concentrated in bottom sediments are known to be toxic in their free (dissolved) state in water and when absorbed into body tissues from food. A major problem in this area has been the method of assaying for toxic metals, as some elements considered to be pollutants are found within the basic chemical composition of the sedi- ment particles. The Crystalline Matrix Study (11) supported by the CE showed that a number of toxic metals were bound in the crystalling ma- trix of the sediments. In making bulk (total chemical) analysis of sediments to determine their pollutant burden, internally bound metals have been included in the analyses in the past. This may lead to false estimations of the pollutant potential of a given sediment so tested. New research in this area is summarized in the Effects Section. Waste effluents and organically enriched bottom sediments consume large amounts of oxygen when they are released to the water column, causing biochemical oxygen demand (BOD). One concern in the Bay system has been the possibility of dredged sediments reacting with oxygen in the water to the detriment of oxygen-requiring organisms. This topic is further considered in the Effects Section below. Normal processes of decomposition produce ammonia and hydrogen sulfide in organically enriched estuarine bottom sediments. These substances are highly toxic to many organisms if not well diluted. Potential im- pact of their release during dredging is further discussed in the Effects Section. -14- TABLE 2. COMBINED MUNICIPAL AND INDUSTRIAL MASS EMISSION RATES Constituent Mass Emission Rate Tons/Day* Unit Mass Fmissinn Ratp will V I IU J J UMI i J J 1 \J ! 1 1 \U L- C Ibs/capita-day* COD 810 0.54 BOD5 271 0.18 Suspended Solids 278 0.18 Oil and Grease 61 0.040 Total Nitrogen 53 0.035 NH3 - N 33 0.022 N03 - N 2.6 0.0027 Phosphate 42 0.028 Phenols 1.5 0.001 Gross Heavy Metals 11.4 0.0075 Relative Toxicity** 700 mgd 232 gal/capita-day Col i form MPN , 4.34 x 10l7/day 1.43 x lOU/capita day Waste Flow 690 mgd 230 gal/capita-day *unless otherwise noted *waste toxicant flow diluted with non- toxic water that will kill one-half the test animals in two days (test animals are stickle- backs) From: Pearson, E.A. et al , 1967. Summary and conclusions. V 7, Comprehensive study of San Francisco Bay. Sanitary Engineering Research Laboratory, University of California, Berkeley. #67-5. -15- Notes on Bay System Biology The scope of this report prevents an extensive description of the biol- ogy of the San Francisco Bay system. Interested readers should consult the CE Composite Environmental Impact Statement (3) and the Biological Community Study (13) which describe numerous aspects of biology and provide literature summaries. Nichols (15) provides a comprehensive review of biological diversity studies carried out on the benthic (bot- tom) organisms of San Francisco Bay. The San Francisco Bay ecosystem is dominated by the above-described water flows and sediment dynamics. The energetic basis (food source) of the estuarine food webs is probably phytoplankton production, sup- plemented by tidal flat production from benthic micro- and macroalgae. There is probably not much organic matter available from the small remaining acreage of marshes and delta outflow, although there may be a significant energetic input in the form of dissolved organics from waste inflows. Primary production and secondary bacterial production supported by dissolved organics is fed upon by the numerous filter feeding organisms in the tidal flats and bay bottoms. This is seen in the great preponderance of filter feeding mollusks composing the biomass as shown by several biological surveys in the Bay. The SERL study (4) found total benthic animal "biovolume" of species to in- clude 70 percent mollusks (clams, mussels, oysters, and snails), 25 percent annelids (segmented worms), and 5 percent arthropods (shrimp, crabs, and their small relatives). Table 3 summarizes the main habi- tats of the system and representative organisms found in them. This table is an oversimplification as these habitats have diverse sub- divisons, depending on currents, salinity, light penetration, food sources, sediment grain size, predation pressure, and pollutant im- pacts. Since some of these factors change from season to season and from year to year, it is not surprising that experts consulted at the California Academy of Sciences considered it impossible to produce distribution maps for any given species in the system. Nichols (16) ascertained that no major pollutant effects can now be detected in the Bay simply by looking at areal differences in species diversity, because even near major sewage outfalls species diversity is high. In the SRI study (13) the Oakland Inner Harbor station, which might be intuitively selected as one of the most polluted in the Bay system, contained one of the most populous and diverse faunas in their survey! Clam beds are widely scattered throughout the tidal flats but may vary in location from year to year. Usually, populations of commercial significance are the best docu- mented as to location and abundance. Discussion with California State Fish and Game personnel conducting the major survey on the Dungeness crab (Cancer magister) revealed that there is still not enough knowl- edge of the life history of juveniles in the Bay to accurately predict where these animals will be at any given time. -16- 01 r. 0) TJ 13 cu l 0) i 01 XI cO 1 OJ cO c 03 0) 03 00 o CO 1 « a> •H 13 5 -H u „ u XI O 03 03 03 l-l 0) >4H o GJ o CO 0) o 0) 0 XI •H rH CO •H VH 03 N 03 rH - 03 XI J*! 01 4J 00 a CJ 01 O 03 •H CJ rH CO rH - XI CO Xl fi C 01 •H «H r-l CO 03 d 03 d cO CO o i-i d 14-1 •13 03 0J 0 -rH Vh U 00 4-1 o 0) CJ a 03 a .d 4J C4H CO o u J* Xl - > rH ■H co d cO 0) Xl o d 03 03 3 CO Pm — I crt rH ■r-4 d - cO 03 -n -a O cJ 0* CJ MH M r~* Cy U* " XI rH rH cO •rH CJ CJ H O 03 03 CO a a J_| r. 4J 03 - cO r a CL 4J rH -H o o 6 00 03 03 O 03 JJ 03 o o OJ Uh 01 •H 4-1 •H 13 13 03 a u a 03 a 4J 4J d 03 r-l 13 a r-l r-l U 3 03 CJ i-i 3 M 4-1 CO 0) cO OJ X! x: O -H r-H •H ■H O r-l O 0 XI rH 3 4-1 OJ H a 03 p d a > o X a ft B cn >> 4-1 •H - 03 03 03 03 03 13 |H CO 13 rH »> 4J „ 4-J O 00 4-1 O o o CO d CO d O OJ d o o 4-1 c- x: CJ 0) d 01 '4H 4-1 OJ C4_| <4H CJ CO ■H H •H •H d ■H w CO OJ •H X! V-l X! rH OJ -H U 01 0) S 4J XJ 03 4-1 03 4-1 u 4J 4-1 4-1 03 3 3 3 3 CO 0) 3 co CO •H 4-1 OJ 01 !>~> >H 3 rH d rH 4J d rH rH C G rH H 4J M-i '-M 3 CO 3 3 CfJ X) XI ■H CJ rH - CJ CJ oo d CO cO d •H 4-J rH 4-1 •H 4J 4-1 -H •H 4-1 M •r-( •H •r-l •H CO XI CO XI 4J 03 x: 4J ■u XI o rH na oo -o oo Vh X» 00 u u oo O <0 crt CO •H -H •H •H cO 3 •H CO CO «H r-H a 03 4-1 rH 4-J rH a 03 rH a CX rH CO CJ •H a) 4-1 4J CO -a u d 4J s B a 0) cO 03 XJ 03 4-1 C/3 <0 4J •H X) CO 0) X! ■H >*> u crj XI pQ 4J a) c —1 rH CU 13 CO :0 CO o 0) ■H OJ X) rH 13 rH o o 4-1 B •H CO •H CO 03 4J 13 •H n 0J 01 H rH •H Vh -h CJ aj > > 0) 0) iJ 0) 4-1 C 4J O o > 4J X) 4-1 X CO CO X3 Xl 01 d 3 C 3 "3 CO CO rH ■H 03 •rH CO 1 En c cO in 03 13 4C C •*; o 00 oo a u CJ d OJ 03 •H •H •H 0) 4-1 4-1 U 42 oc rH 1-1 rH r-H CO OJ 4-1 cO •H OJ Xi CO rH u d rH a 4-i CO 4-1 03 '4H CO OJ 0) CO H CO X a 4-1 -a X! H 01* J •H 0) 03 CO c cO x> r*i rJ -a OJ U 0) •H CO •rH a O t-i C3 H O al xi >> o 0) u .k: 01 13 4J •H CU CO -a rH 4-1 M 3 O CO 4J B CO 03 X II II II a 03 3 -o OJ c >. 3 l-l 3 •H a. B 3 rH r H o CO u •H U •H c <+-< •H •r-l •H 4J 3 O CO <4H -K •K -17- Although many different species populate the broad expanses of Bay bot- tom, most exhibit few major body types and are very small and inconspic- uous. Most are fully adapted to existence in soft mud. In addition to the easily visualized market clams, the mud supports large populations of tiny clams no bigger than this typescript (Gemma gemma, Transenella tantilla) . There are a few species of large clam worms sometimes used as bait, but dozens of species of tiny worms (1-2 cm) are very difficult to identify taxonomically. There are a few species of large crabs such as the Dungeness, and the common bait shrimp, and many more species of tiny amphipod crustaceans which build protective tubes in the mud. Most of these organisms and other miscellaneous species of the Bay bottoms are f i 1 ter feeders which remove particulate foods from the water or deposit feeders which sort particulate foods from deposits at the mud- water interface. Small benthic organisms from the basis of the food web leading to the production of fishes, shrimp, and crabs. The benthic community of the Bay is adapted to natural stresses in various ways, from physiological adaption to reproductive strategies. As it presently stands, the Bay's ecosystem is the product of adapta- tion to over 100 years of "industrial man" influencing the estuary. This includes waste flows, hydraulic mining debris, and the introduc- tion of hundreds of new species, both intentionally (striped bass) and unintentionally. The concerned reader, aside from reading publications on this topic, may obtain an excellent impression of the types and kinds of organisms in Bay system bottoms by inspecting the collection of invertebrate organisms of the San Francisco Bay system maintained at the California Academy of Sciences. Dredging and Disposal Practice Dredging is the process by which sediments are removed from the bottom of streams, lakes, and coastal waters, transported by ship, barge, or pipeline, and discharged (as spoil) to land or water. The usual pur- poses of dredging are to maintain, improve, or extend navigable water- ways, or to provide construction materials such as sand, gravel, or shell (12). Most of the dredging and disposal in the San Francisco Bay system is carried out by the CE, San Francisco District, using West Coast CE equipment. Smaller amounts of dredging and disposal are carried out directly by the Navy and certain municipalities which own their own equipment. A number of private firms are available for dredging ac- tivities, mainly in service to corporations and municipalities. The Sacramento District, CE, is responsible for maintaining the Sacramento ship channel from Chipps Island to Sacramento. It is of importance to distinguish between maintenance dredging and new work dredging. Maintenance dredging is carried out on a routine basis, usually on long-term permits or by Congressional authorization. This dredging removes sediments which have been deposited in navigable -18- waters on a regularly scheduled basis to prevent shoaling of routinely used channels. This type of dredging removes sediments which have accumulated over short periods of months or years at typical rates es- tablished for each given locus over long periods of observation. For example, the main channel through the San Francisco Bar outside the Golden Gate has been dredged annually since 1922. New work dredging is carried out by special permit (see regulations section below) in areas previously not subjected to dredging. This type of work is more likely to release pockets of contamination which represent long periods of accumulation. The CE Composite Environmental Impact Statements lists their maintenance projects as shown in Table 4. Methods of Dredging Three major types of equipment used in dredging and disposal are illu- strated in Figure 4. In the San Francisco Bay system, the majority of sediments are removed from maintenance projects using a hopper dredge. This dredge is a self-propelled ship with holds (hoppers) wnich contain the dredged material. The ship drags a pair of suction heads through the site to be dredged, pumping the sediments into the hoppers. With hoopers full, the ship raises the drag heads and proceeds to the (aquat ic) disposal site, where doors are opened in the bottom of the ship, releasing the dredged material. For example, the CE uses the hopper dredge "Harding" for applicable projects in the Bay system. Dredging is done in the Mare Island channel on a twice-yearly basis with the average amount removed of approximately 2 million cubic yards per year. The hoppers of the "Harding" can contain up to 2700 cubic yards of sedi ment. The dredge works 24 hours round the clock from September to November, removing sediment deposited from summer resuspension and from February through April, removing new material brought down the rivers in winter from the Napa and Central Valley. In low-flow years, the amount to be dredged may be significantly reduced. In the first dredg- ing period of 1977, the Mare Island project only required two days of work by the "Harding", suggesting the low levels of sediments brought in by extremely low river flows, typical of the current drought (or in the future by reduced Delta outflow). Mare Island dredged material is carried 2.8 miles from the dredging site and released at the disposal site on the northern margin of the Carquinez Strait. Other methods of dredging include the clamshel 1 dredge and hydra ul ic cutter head pipeline dredge. The former method employs a clamshel 1 bucket which removes "bites" from bottom sediments as done by drag- lines in terrestrial situations. Clamshell dredging is usually done in areas of restricted ship movement such as harbors and marinas. Dredged material is deposited in barges, usually with bottom-opening doors. Both barges and dredge are moved by tugboat to the dredging site and loaded barges are taken to disposal sites by tugboat. Pipeline-dredges employ a cutter head which is lowered to the sedi- ment and moved across the sediment face. Dredged material is pumped to the surface and then into a temporary pipe string which is mounted -19- TABLE 4. CORPS MAINTENANCE DREDGING PROJECTS IN SAN FRANCISCO BAY AREA (Ref. 2) Location Approximate Qty. Dredged, Authorize! ion (cubic yard*) Ft ■auencv I'roposad Proposed Data of Haxt Avera^ : Annual Disposal Site Ha Intenanca Qty.(c»' • 1c ydu)L San Francisco rfirbor R&HA 2 o£ 192 7 FY 76 (lain Ship Channel and amendments 1,000,000 1 yr. San Franc leco Bar I, 100,000 Kock removal none completed 0 Presidio Shoal none Inactive n u none Inactive _ 0 none inactive 0 roint m»ox jnoai lnac t ive _ 0 5.F. Airport Channel none Inactive - 0 Islaia Creek Entrance 257,000 16 yr. Alcatraz indefinite 13,000 San Rafael Creak R4HA Of 1919 260,000 6-8 yr. land FY 7 1 (4,000 R&HA of 1930 396,000 12 yr. San Pablo Bay FY 77 33,000 Sun Pablo Bay and Mara R&HA of 1927 Island Strait and amendments 76 124,000 Pinole Shoal Channel 619,000 2 yr. San Pablo Bay PY 2 , Hare Island Strait 1,250,000 0.5 yr. Carquinec Straits FY 76 '00,000 Richmond Harbor R&HA of 1917 480,000 1 yr. Alcatraz FY 77 .80,000 and amendments Oakland Harbor R&HA of 1874 76 i 00, 000 Oakland Outer Harbor and amendments 300,000 - 1 yr. Alcatrax FY Oakalnd Inner Harbor 350,000 1 yr. Alcatraz FY 76 ■50,000 San Lesndro Marina R&HA of 1970 225,000 5-6 yr. land FY 78 4 2 , 000 kedwood City Harbor R&HA of 1910 325,000 1 yt- land FY 76 or 77 23,000 and amendments S.P. Hbr. & Bay - Sausa- R&HA of 1950 90,000 3-4 yr. Alcatrat FY 77 or 78 26,000 Uto Operatlona Base Suisun Bay Channel R&HA of 1919 1 1 A AAA 220,000 1 yr. Suiaun Bay FY 76 and amendments luisun (Slough) Channel R&HA of 1910 180,000 2-3 yr. land Indefinite 72.000 and amendments New York Slough R&HA of 1876 15,000 3-5 yr. land Indefinite 4.000 and amendments TOTAL R&HA PROJECTS 5, '23.000 cm. cord Naval Weapons lnter-servlce 50- 52,000 2 yr. Suiaun Bay FY 78 25,000 Station Alameda NAS UJ CM o o r-i i— i U_ O u_ t— 1 o to «— 1 Q o: o UJ •— l CO cc O s: lli t-H ZD D_ Z Q t— Z Ul cc q 1— UJ tn ^— <_> 00 Q UJ Z _J - 2: Q Q_ CO co co CO co cr> co co o CM 00 o CO CM O LO CO CO CO •r- *«/> S- T3 i— CO C 13 <4- T- •!— O > r— -o C CO O cn-t- "O -4-> CO (O s_ +-> Q CO I -o c co o Cn>i- "O 4-> I CO fO C S- 4-> ZD "O CO I -27- The disposal site in the South Bay which received a single load of dredged material showed populations and diversity comparable to the control site after a few months. Although extensive surveys of species and numbers of organisms were made at study sites, and a number of chemical parameters were recorded, it was concluded that "underlying relations among biological and environmental variable are complex, and that additional field and laboratory studies would be required for thorough identification and understanding of such relationships (13)." Trends suggested from their data showed small populations and low di- versity correlated with high salinity and sediment mercury and sulfide concentrations, and high diversity and large populations with high dissolved oxygen, turbidity and sedimentary zinc and clay content of sediments. This study showed the great difficulties in determining gross effects of dredging and disposal in San Francisco Bay as compared with the more easily studied quiet, shallow waters. The Stanford sur- vey noted marked seasonal variations in organisms. As a specific ex- ample of the difficulty and expertise required in this study, over 130 species of taxa (kinds) or organisms were found in the Oakland Inner Harbor station alone, with an average number of organisms per liter of sediment being 867.5 (yes, they are small). A total of 131 ,256 specimens were collected during 5 surveys. McCauley et al (22) monitored effects of dredging on the benthic faunal abundance of a dredged channel in Coos Bay, Oregon, and found that in- fauna readjusted to pre-dredging conditions within 28 days. At the spoil site, readjustment took about two weeks. More simplified tech- niques were used than the Stanford study, however, pointing out the great difficulties in comparing different studies because of the use of different methods between research groups. In a study funded by the CE Waterways Experiment Station, Vicksburg, Mississippi ,x personnel of the Moss Landing Marine Laboratories inves- tigated recovery of fauna in dredged and disposal areas in Monterey Bay. Their findings suggested that communities in areas which are normally stressed show more rapid recovery of populations and animal diversity than biotic communities which are not normally stressed (23). Thus, typically wind and sediment stressed areas in San Francisco Bay are probably more resilient to long-term effects of sediment disposal than the 100 fathom (Farallon) ocean disposal site which undergoes very little natural perturbation. Effects of burial on organisms are important in disposal sites where mounding of dredge spoil occurs. Another DMRP study, by the Univer- sity of Delaware, was carried out to determine abilities of organisms to escape burial in various types of sedimentary material (24). In laboratory experiments, it was found that numerous types of orga- nisms (crabs, clams, snails, amphipod crustaceans, polychaete worms) were capable of escaping from as much as 32 cm deep burial. Notable *Dredged Materials Research Program (DMRP) -28- exceptions were small snails, and organisms buried in exotic sediments (sediments in which organisms do not normally live). Great variation was found with temperature, stress condition of the organisms, and other factors; and it was concluded that generalizations as to disinterment behavior could not be made between species groups, although knowledge of morphology and behavorial characteristics were in general useful in pre- dicting migratory behavior. The authors recommended field studies be carried out under actual dredging conditions. Presently used disposal sites in San Francisco Bay, being in high energy areas, do not allow long-term mounding of sediments. Physical smothering of shellfish beds is not a problem in San Francisco Bay with current and projected dis- posal practices. A specific problem related to both direct and indirect impacts of dredged material is the possibility of formation of fluid mud flows from dredged material. Formation of fluid muds occurs when mixing energy is not great enough to totally resuspend sediments in the water column, and dredged sediments are caused to flow across bottom environments, smothering resi- dent fauna. A DMRP study by the Virginia Institute of Marine Science has shown that fluid mud flows induced in the upper reaches of an estuary could have significant lethal effects on the macrobenthic organisms (clams and insect larvae) although some were more sensitive to this stress than others (32). In San Francisco Bay, concern has been shown by the Depart- ment of Fish and Game personnel that such fluid muds could severely im- pact juvenile Dungeness crabs in certain bottom areas of the Bay. Fluid muds are difficult to measure, and may occur due to natural causes. Changed Circulation Regimes Typical dredging and disposal as currently practiced probably has little effect on the circulation regimes in the Bay. The CE, San Francisco Dis- trict, is currently preparing an Environmental Impact Statement for the Baldwin Ship Channel project which has the potential of increasing sa- linity intrusion into the Delta. Dredging of estuarine channels which cause significant new salinity intrusions, have the effect of moving the null zone upstream, resulting in greater sediment deposition in upstream reaches of estuaries (21). This produces new demands for dredging of the upper reaches of estuaries, where significant environmental effects may accrue. Indirect Effects Effects which do not occur as a direct result of the activities of dredg- ing and disposal include physical impacts of resuspended sediments, biochemical oxygen demand of oxygen-reactive compounds stored in bottom sediments, and release of toxic or blostimulative materials from sediment storage. A number of research projects have recently been completed which bear on these potential effects on the estuarine fauna of San Francisco Bay. -29- Two studies were carried out by researchers of the University of California Marine Laboratory at Bodega Bay to determine the effects of contaminated and uncontaminated sediment loading on the survival of sensitive test or- ganisms (26, 27) common in the Bay system. Parameters measured included amount of sediment maintained in suspension, temperature, and oxygen con- tent of the water. Organisms tested included bay mussels, a clam worm spe- cies, an isopod species (Synidotea), Bay shrimp, shiner perch and striped bass. These species are widely distributed in the Bay and served as test species of ecological importance. In general, invertebrates were highly resi stent to the effects of suspended solids in the water (tens of grams per liter) and were more effected under conditions of higher temperature and low dissolved oxygen. Organisms commonly found in muddy environments were least sensitive. Fishes were sensitive to suspended sediment (few grams per liter) conditions, particularly at high temperature and low DO. The researchers concluded from the results that the organisms would be insensitive to suspended sediment loads typical of areas around dredging activities determined in CE water column studies (28). These studies have shown that the suspended sediment plume does not interfere with the upper two meters of water during both dredging and disposal, and that although there are dissolved oxygen reductions near the dredge during dredging and disposal operations, these effects last only a few minutes due to rapid mixing of well oxygenated Bay waters. From these data and the data on sensitivity of organisms, mitigation of these localized effects could be obtained by restricting dredging to winter months when temperatures are low, and disposing of sediments such that they are maximally dispersed to minimize oxygen demands around the dredge. Sherk et al (29) have found significant lethal and sublethal effects of suspended sediments on certain estuarine fishes which are not adapted to typical mud bottom conditions. Their results suggest that the more sen- sitive fishes such as menhadedn, white perch, bay anchovy and striped bass larvae, if unable to escape dredge and disposal plumes for periods of days, could be adversely affected by sediments from dredging and dis- posal activities. It is unknown if this is likely to occur near San Francisco dredging and disposal sites. Comprehensive studies of the effects of dredging on the fishes of Chesapeake Bay (3) were unable to demonstrate gross effects of overboard disposal of dredged sediments using caged fish experiments and commercial type research gillnetting. Furthermore, no gross effects could be demonstrated on phytoplankton primary productivity, zooplankton, and fish eggs and larvae. A review of the effects of dredging and disposal on zooplankton (31) suggests that significant effects of suspended sediments can occur if plankton populations are localized and not dominated by oceanic processes im- pinging on the estuarine habitats. It is suggested that any impact on zooplankton can only be determined on a case-by-case basis with exten- sive knowledge at hand concerning the biology of the zooplankton popu- lations. Since this data is unavailable for San Francisco Bay, no predictions can be made concerning zooplankton effects. -30- Toxicant Release and Uptake A great deal of reserach has been carried out recently due to the need for determining the effects of deleterious materials released from dredged sediments. This work has been carried out mainly in providing basic data for the development of dredged spoil disposal criteria (DMRP studies) and in determining environmental impacts of toxicants released into San Francisco Bay waters (DDS studies). A. Heavy metals Serne and Mercer (11) have studied the release of the heavy metals, Cd, Cu, Fe, Hg, Pb, and Zn from selected San Francisco Bay sediments as a function of various physical and chemical parameters including Eh (redoxpotential ) and salinity. Sedi- ment samples from ten sampling stations were characterized with respect to heavy metal content, particle size, mineral content, total sulfide, organic carbon, cation-exchange-capacity, and PCB content. The release of heavy metals was determined using a semi-selective extraction procedure, where the sediment is extracted sequentially with interstitial water, ammonium ace- tate, hydroxlyamine hydrochloride, hydrogen-peroxide, and so- dium citrate dithionate. The greatest portion, 30-97%, of the heavy metals, Cu, Fe, Hg, Pb, and Zn, were bound in clay or crystalline lattice sites. The greatest portion of Cd was associated with sulfide-like sites (extractable with hydrogen peroxide). Elutriate test data were also compiled for Fe, Cd, Cu, Zn, and Pb. These data are summarized in Table 6. Chen, et al (33) have studied the release of heavy metals from dredged material. They found no release of Ag, Cd, Hg. The metals, Cr, Cu, and Pb were released at levels of from 3 to 10 times background. Amounts of Fe, Mn, and Zn larger than 10 times background were released. Except for Fe the amounts re- leased are in the sub ppm to ppb range. Most of the soluble phase concentrations were well below the allowable levels of the ocean water discharge standards. Lu and Chen (34) reported a study on the migration of heavy metals from polluted sediments into seawater. Reducing con- ditions favored the release of Fe and Mn; whereas, oxidizing conditions favored the release of Cd, Cu, Ni , Pb, and Zn. The migration of metals is controlled by the chemistry of the immediately overlying water rather than the type of sediment. The factors affecting metal migration were studied, and a model is proposed. Anderlini, et al (35) have examined the uptake of heavy metals by estuarine organisms and sediments during dredging operations in the San Francisco area. These authors conclude that dredging -31- TABLE 6. Release of Metals from San Francisco Bay Sediments Elutriate Metal Dissolved 02 Ratio* Effect of Salinity Fe 1 ow 50-3000 None high 2-9 None Cd low 0.2-2 Less in higher salinity high 0.2-2 Less in highest salinity Cu low 0.2-8 Less in higher salinity high 0.3-9 Less in higher salinity Zn low 0.3-7 Less in higher salinity high 1-7 None Pb low 0.2-6 Less in higher salinity high 2-9 Less in higher salinity a. Elutriate ratio is the amount released divided by the amount in the disposal site water. -32- does not affect the levels of heavy metals in nearby sediments or invertebrates. This observation is likely the result of the un- availability of sediment-associated metals since the uptake of dissolved chloride salts of Hg, Pb, Cu, Cd, and Ag by Ma coma was established in laboratory experiments. A similar study (36) has examined the release and uptake of heavy metals (Ag, As, Cd, Cr. Cu, Fe, Hg, Mn, Ni , Pb, Se, and Zn) dur- ing a dump of 10,000 m3 of dredged material in San Francisco Bay. The concentrations of these metals were monitored in selected benthic invertebrates, mussels transplanted to the disposal site, sediments, settled and suspended particulates, and water before, during and after the disposal operations. The results of this study are summarized as follows: Benthic invertebrates No effect on heavy metal concentrations Surface sediments Water Transplanted M. edulis Higher Fe and Cu levels in disposal area Short-term increases in dissolved Cd, Cu and Pb. No effect on heavy metal concentrations The overall conclusion of this study was "The amount of trace elements redistributed annually by all dredging activities is much greater than the annual input from the EBMUD outfall, but is almost inconsequential in relation to the element redistri- bution by settling particulates." Neff, et al (37) in an extensive research program on the uptake of metals from metal -containing sediments found there were no simple principles which covered all organisms, sediments and metal contaminants. It was concluded that metals were taken up with difficulty by most organisms tested, and that development of a simple extraction scheme for predictive effects of heavy metal uptake by benthic organisms in general is presently not possible. Pesticides and PCB's Fulk, et al . have reviewed the literature on pesticides and PCB's in sediments (38). Algae, suspended solids, bottom sedi ments, and water all contain various chlorinated hydrocarbons. The studies conducted on the adsorption and desorption of chlorinated hydrocarbons on solids have generally found that these materials are more readily absorbed than desorbed. -33- Fulk, et al . (38) have analyzed the sediments from five areas for aldrin, dieldrin, endrin, lindane, 2,4-D esters, DDT analogs, toxaphene and PCB's. PCB's, dieldrin and the DDT analogs were the most prevalent. The desorption of the latter materials was studied. No DDT analog release was observed. Release from in- terstitial water was negligible. Some Dieldrin release was ob- served in the sub ppb range. On the basis of these laboratory studies, it appears that release of these water insoluble pesti- cides will not occur to an appreciable extent during dredging. To my knowledge the release of Kepone from sediments has not as yet been studied. The situation in the James River with wide- spread Kepone contamination in organisms and sediments may be an unusual case. The (water soluble) Kepone may dissolve upon dis- ruption of the sediments. Anderlini, et al (36) monitored release and uptake of PCB's and compounds of the DDT group during a disposal operation in San Francisco Bay. Some uptake of p,p'-DDE was observed but the levels of the other chlorinated hydrocarbons remained constant in Mytilus edulis. Chlorinated hydrocarbons were released to the water column resulting in 3-10 fold increases in the chlo- rinated hydrocarbon levels in the water immediately after dis- posal . C. Oil and Grease One of the major contaminants in estuarine sediments are "oil and grease" residues, consisting mainly of petroleum derived hydro- carbons and their breakdown products. A laboratory study recently completed by DiSalvo et al (39) exposing mussels, crabs and clams from the Bay estuary to heavily contaminated sediments from Puget Sound and New York Harbor showed minor uptake of hydrocarbon resi- dues from sediments. Field experiments carried out by DiSalvo et al (40) showed that hydrocarbons were taken up by mussels sus- pended in San Francisco Bay, and it was suggested that weathered hydrocarbons in sediments were tightly bound, and that uptake of hydrocarbons by uncontaminated mussels occurred from newly released pollutants or oil droplets accommodated in the water column (39). This research has suggested that bulk analyses should be carefully reexamined as a disposal criterion, as this parameter appears to have little relevance to possible environmental impacts. Specific compounds normally part of the oil grease fraction are the car- cinogenic compounds which usually occur in minute quantities in sediments. This topic is further discussed in the ABAG Special Study: Toxicants in the San Francisco Bay Estuary (1978). D. Contaminant microorganisms A problem associated with release of dredged sediments is the possible dissemination of enteric bacteria, viruses, protozoa and other microorganisms which may be taken up by commercially valu- able shellfish in their filter feeding processes. -34- Fecal col i forms and enteric pathogens have been found in bottom sediments (41,42). Dredging of the Mississippi River navigation channel has been shown to result in increased fecal col i form concentrations by a factor of 2-5 in the immediate area of the dredging. Highly pathogenic protozoan cysts have been isolated from contaminated sediment deposits near New York and Baltimore (44). We do not know to what degree the dredged material in the Bay. is contaminated with persistent undesirable microorganisms from the public health standpoint; further information on this topic is available in the ABAG Special Study: An Assessment of the Potential for Commercial and Recreational Harvesting: San Francisco Bay Shellfish (1977). E. Hydrogen Sulfide (H2S) and Ammonia (NH3) These two compounds, normally formed in organically rich anoxic estuarine sediments, are highly soluble in water. They are both toxic to many aquatic organisms and are of interest with respect to water quality criteria in the Bay. Since the San Francisco Bay system sediments are highly enriched in iron, free H2S is expected to react to form insoluble iron sulfides (which color the sediment black). Serne and Mercer (11) have verified this hypothesis, finding no detectable free H2S which could be re- leased from the dredged material. Ammonia is one of the potentially toxic materials known to be released from anoxic sediments, and routinely found in evalua- tions of sediments using the elutriate test.* Anderlini et al (35) found minor indications of ammonia increase after a sedi- ment disposal operation, with small rises in water near the spoiling followed by rapid returns to baseline levels. Ammonia is also a plant nutrient and may lead to eutrophi cation pro- cesses as discussed in the ABAG Special Study: Eutrophication in San Francisco Bay (1978). Land Disposal Confined or unconfined land disposal of contaminated dredged material appears, from literature thus far reviewed, to be an unattractive al- ternative to aquatic disposal for a number of reasons. 1. It is only a temporary solution, as pointed out by Schubel and Meade (21) in their description of problems in the Delaware estuary. There are limited numbers of receiving sites and massive continuous accumulations of sediment which must be accommodated. 2. Land disposal of contaminated dredged materials may have worse adverse environmental effects than aquatic disposal as contaminated runoff from the material may re-enter sensitive inshore nursery areas rather than being sub- jected to large forces of dilution based on estuarine water circulation (45). *See Section III. -35- 3. The properties of Bay mud which is the main material taken from maintenance dredging projects is "a soft, plastic, black to grey silty-clay or clayey-silt with minor organic material and clayey fine grained sand which has been deposited in the Bay largely by flocculation" (generally the consistency of toothpaste) (2). It has poor bearing capacity, requires ex- tremely long times for dewatering, and effectively prevents all other land use for long periods of time, including the growth of plants and animals (46). Whereas the impact of aquatic disposal is not well known, the impact of land dis- posal is clear. All life is effectively excluded from the disposal area for long periods of time. Concluding Remarks on Effects Most of the research reviewed here is so new that it has not been criti- cally reviewed by the scientific community in general. For the present context, the conclusions of the authors have necessarily been taken at face value without critical review of the data. Indeed, limited pre- liminary critical review made by our group to date indicates that there are a few discrepancies here and there in chemical studies which will eventually give rise to academic debate concerning the significance of some of the results. However, the overview of the research is encour- aging, especially in light of the natural processes operating in San Francisco Bay which aid in the dilution of wastes and rapid oxygenation of Bay system waters. Although the studies seem detailed (and expensive), they are only a beginning, and the discerning reader will have noted there are few de- monstrative experiments which clearly show effect, or lack thereof, of dredging and disposal on any particular biological resource of the Bay ecosystem. Obviously, this is in the realm of future research needs as outlined in our final pages. We cannot emphasize too strongly the need for basic research on which to formulate the proper questions which will lead to (empirical) demonstrative experiments in the future on specific impacts of specific dredging projects. -36- SECTION III REGULATION OF DREDGING AND DISPOSAL General Considerations The regulation of dredging and disposal is based on the broad action that is required to protect the diverse resources which come under the heading of "environmental protection." Numerous Federal and State agencies are charged with different aspects of environmental resources protection, each responsible for evaluation of potential environmental effects of dredging and disposal in the San Francisco Bay system. Any real or hypothesized impact envisioned by any agency is able to delay or block the permitting process. Environmental legislation and the multiplicity of involved agen- cies has complicated the permitting process for dredging and disposal be- cause of the lack of objective information on environmental effects and objective criteria for evaluation of any such effects. New and emerging research results, discussed above in the Effects Section, are showing that some interim criteria which have been used in the past are of questionable value. An in-depth study of the regulation of dredging has been carried out by the San Francisco Bay Conservation and Development Commission (BCDC) (18) which has proposed numerous suggestions for accelerating the permitting process. The following discussion presents an introduction to the laws governing dredging and disposal, as applied to the San Francisco Bay system. At the heart of the entire matter is the basic assumption that scientific research has either provided or is capable of providing objective criteria for assessment of the potential impacts of dredging and disposal. Costs of research and time schedules required for obtaining the results make this assumption problematical. Legal Framework Dredging and disposal are regulated by Congress through permit processes under basic control of the U.S. Army Corps of Engineers (CE) in close cooperation with the Environmental Protection Agency (EPA). Under the Rivers and Harbors Act of 1899 (Sec. 10), the CE maintains permit power over all dredge and fill operations in navigable waters of the U.S. Section 404 of the Federal Water Pollution Control Act (PL 92-500, 1972 amend.) gives CE permit authority over the disposal of dredge and fill material into all U.S. waters (the territorial sea). Ocean dumping of dredged materials is regulated by the EPA under Section 102 (a) of the Marine Protection, Research and Sanctuaries Act of 1972 (PL 92-532). The preceding Acts form a base of enabling legislation, following which, interpretations and explanations of each Act are made by administrators charged with enforcement of the Act. This includes rationale, rules and regulations, and test criteria to be met in compliance with the Act, as well as definitions of terms and permitting procedures promulgated by the administrator after his review of the Act, relevant court decisions, and -37- public comments. Publication of this material is made in the Federal Reg- ister. For example, the 11 January 1977 Federal Register includes a final revision by the EPA administrator of the ocean dumping criteria originally established by PL 92-532. Within this publication it is stated that a man- ual will be developed by EPA and the CE to implement the criteria. This manual (19) has recently been released and will undoubtedly be revised as experience is gained by laboratories and agencies charged with enforcement of its provisions. An essential part of all regulations on dredging and disposal has been the identification of agencies which are to be consulted prior to granting of dredging and disposal permits. Federal and State agencies with commenting or permit certification power are listed in Table 8. The main dredging projects in the San Francisco Bay system are carried out by the CE based on direct authorization by Rivers and Harbors Acts of Con- gress beginning as early as 1876 (See Table 4). These projects, discussed in detail in the CE Composite Environmental Impact Statement (3), fall outside the jurisdiction of BCDC. All other dredging projects in the Bay system require the granting of a permit by the CE. The CE cannot make a decision on the permit until it has received comments from the various agencies listed in Table 7 and the State Water Resources Control Board has issued a certification of approval. After institutional approval is granted, a public notice is posted by the CE and substantive objections are taken into account. Any person adversely affected may request a pub- lic hearing to express grievances. The decision to issue the CE permit is based on public interest, including needs for navigation, fish and wildlife, water supply, flood damage pro- tection, ecosystems, and, in general, the needs and welfare of the people (18). Although the existence of certain environmental impacts has been recognized by the San Francisco District Corps of Engineers, they may be outweighed by the needs for navigation, national defense, and other con- siderations as expressed in the Composite EIS (3). Criteria for the Disposal of Dredged Material Currently employed criteria applicable to the dumping of dredged material in San Francisco Bay and in the ocean were adopted by the EPA Region IX administrator based on data published in the Federal Register, 1971. Sediments must be analyzed for content of mercury, cadmium, lead, zinc, and oil and grease by standard methods which analyze the total sediment (bill k analysis) . Research has shown, however, that there is little cor- relation between bulk analysis of sediment and the metals species actu- ally available to cause toxic effects in organisms. A new procedure, termed the elutriate test was put forth in the 15 September 1975 Federal Register. In this test a given volume of sediment is shaken with a given volume of water, and the water is separated and analyzed for selected toxic metals. If the elutriate water value exceeds disposal site water -38- +J M— c O CD >> E c CU fO "O CD 0 JZ CO C 4-> ■1— -u> CO CU fO +J O E _J 4-> «+- CO Lu CO CO CO > O CO CU co Cn CO >- $- c JZ •r— o h- +-> 01 +-> «3 G CO S- oS 2: Q_ t—i <_) CO CD JZ r — •r- S- o> •— * CO 1 «o C <4- CU CO -l-> JZ 1 — 4 1 — 1 Q. 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A criticism of this method is that testing for a few metals leaves out a whole spectrum of materials that might be toxic for organisms. Criteria development proceeded one step further with the publication of the ocean disposal criteria manual by CE and EPA (19). This manual specifies the use of bioassay testing to evaluate the toxic potential of dredged ma- terial by exposing sensitive organisms directly to representative samples of the proposed dredged material, and, if any deleterious effects on the organisms are caused, for whatever reason, then the dredged material is not certified for ocean dumping and must be placed in confined land disposal sites. -40- CONCLUSIONS 1. Environmental awareness has fostered broad research programs throughout the United States designed to determine the extent and significance of the environmental impacts of dredging. The most significant are the $30 million Dredged Materials Research Program (DMRP) managed by the U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Miss., and the $3 mil- lion Dredge Disposal Study (DDS) managed by the San Francisco District Corps of Engineers. The voluminous results of these programs have either been available for short periods or are just now emerging from various contractors and universities. As a consequence, a great deal of this material has not under- gone critical review and synthesis by the scientific community. 2. The San Francisco Bay Estuarine system is highly complex, both physically and chemically, within the scope of an already com- plex field of estuarine science. The current state of the art does not allow accurate prediction of water currents and sedi- ment flows. The estuary undergoes natural stress in the form of strong circulation patterns driven by tide, winds, salinity gradients, and river inflows. Natural stresses to the biota, typical of most estuaries, are the massive sediment inflows, variations in salinity with river input, and seasonal tempera- ture changes. 3. Further stresses to the system are imposed by industrial civi- lization through removal of river waters, historic hydraulic mining for gold, subsidence due to removal of groundwater, municipal and industrial waste discharge, filling of marshes for agricultural purposes, diking and filling of tidal flat areas, introduction of numerous species and dredging and dis- posal of bottom sediments. Since natural and man-made stress may both cause the same effects on populations of organisms with varying conditions of climate, no generalizations can be made concerning differences in environmental effects between natural and man-induced stress. 4. The preceding two considerations make evaluation of any specific environmental impact, such as dredging and disposal, extremely difficult to define with scientific certainty. 5. Field research in San Francisco Bay has shown significant direct impacts of dredging and disposal on the biota at dredge and dis- posal sites. Due to the circumscribed dredge and disposal areas, these effects can be considered minor within the wide expanses of Bay bottom habitat in which these species occur. Should dredging and disposal at any site be terminated, the sites can -41- be expected to repopulate within periods of months by migration and natural dissemination of eggs and larvae produced in nearby regions of the Bay. 6. Measurements made upstream and downstream of dredging and disposal activities have shown that although there are measurable effects on oxygen, ammonia, and some heavy metals in the water, are rapidly assimilated by the mixing regime in the Bay. A tracer study showed that sediments released at the Carquinez Strait disposal site be- come mixed to minute levels in San Pablo Bay sediments, and that 10-15% of the disposed material is redeposited in the dredged area (Mare Island Strait). (See reference 8.) 7. It can be concluded from the new research data that the method of bulk analysis to determine pollutant impacts should be reevaluated, as presence of metals in sediments is not correlated in a simple manner with their potential for environmental impact on water qual- ity or biological resources. The latest criteria for ocean dumping of dredged material promulgated by the EPA and Corps of Engineers is based on bioassay data where representative sensitive organisms are directly exposed to dredged material in the laboratory to de- termine its potential toxicity. 8. There is no evidence, positive or negative, for making generaliza- tions as to the effects of dredging and disposal on commercially valuable biological resources of the Bay. Only highly specific empirical experiments will demonstrate effects, if any, and due to the multiplicity of environmental variables, specific cause-effect relationships will always be problematical. 9. Aquatic disposal of sediments in high energy areas of the Bay ap- pears from all available information, to be a better alternative than land disposal of dredged materials. Land disposal of Bay mud has readily vi si bile environmental impact, is only a temporary solution, and is fraught with numerous environmental and economic drawbacks. 10. Environmental impact of routine maintenance dredging will be different from new work dredging" Maintenance dredging removes recently deposited material which may reflect institutional ef- forts to remove contaminant sources.* New work dredging may un- cover contaminants which have resided in sediment storage for long periods of time. *Low degree of contami nati on . -42- RECOMMENDATIONS Research I. Carry out correlation analysis between fisheries statistics for market crab, striped bass, and other fish for which data is available and historical data on dredging activity. Com- pensation should be made for lag times between dredging ac- tivity and effects on fisheries. Significant correlations between changes and dredging and changes in fisheries re- sources do not prove effects, but aid in obtaining direction for future studies. II. Develop a routine field monitoring system to determine up- stream-downstream differences in water quality dredging and disposal sites under different conditions of water circula- tion and river input to verify short term water quality measurements made by the Corps. Water quality measurements downstream of dredging and disposal projects to determine loadings of water column with contami- nated sedimentary particles for comparison with ambient values (note: ambient values will contain background contaminant loads from municipal and industrial waste sources). III. Bioassay tests should be conducted on all Bay dredged material as recommended by EPA and CE based on the guidelines recently published (19). ' IV. Field experiments should be conducted, placing caged fish and shellfish upstream and downstream of dredging and disposal activities as reported in reference (30). Organisms of par- ticular importance should be determined by personnel of the State Department of Fish and Game. Suggested organisms in- clude: a. gravid female striped bass, salmon, shad, and anchovies, which could later be spawned in order to determine per- cent of survival of eggs; b. molting juvenile Dungeness crabs, through several molt cycles, maintained in bottom cages near dredging and disposal ; c. clams, oysters and mussels which can be sampled to de- termine profiles of bacterial, viral, protozoan, and other contaminants of public health significance. V. A fully detailed study on a small proejct, such as the San Leandro Marina to determine actual local effects. -43- LITERATURE CITED 1. Pritchard, D.W., 1967. What is an estuary: physical viewpoint. Irv: Estuaries, G.H. Lauff, (ed.). Publication No. 83, pp 3-5, Washington, D.C. 2. U.S. Army Engineer District, San Francisco Corps of Engineers. 1977. Dredge disposal study San Francisco Bay and Estuary. Main Report. 3. U.S. Army Engineer District, San Francisco, California, 1975. Maintenance dredging of existing navigation projects in San Francisco Bay Region, California. Final Composite Environmental Statement. 4. Storrs, P.N., E.A. Pearson and R.E. Selleck. 1966. Comprehensive study of San Francisco Bay, Volume V, Summary of physical, chemical and biological water and sediment data. Sanitary Engineering Res. Lab., Rept. No. 67-2, University of California, Berkeley, CA. 189 pages. 5. Conomos, T.J. and D.H. Peterson, 1977. Suspended - particle transport and circulation in San Francisco Bay: An overview. In: Estuarine Processes, Vol. 2, pp. 82-97, Academic Press, N.Y. 6. Peterson, D.H., T.J. Conomos, W.W. Broenkow and P.C. Doherty, 1975. Location of the non-tidal current null zone in northern San Francisco Bay. Estuarine and Coastal Marine Science Vol. 3, pp. 1-11. 7. Krone, Ray B., 1976. Ultimate fate of suspended material in estu- aries. Proc. Specialty Conference on Dredging and its environmen- tal effects. Mobile, Al . , eds., P. A. Krenkle, J. Harrison and J.C. Burdick, pp. 180-201. Am. Soc. Civ. Engrs. 8. Ecker, R.M., J.F. Sustar and W.T. Harvey. Tracing estuarine sedi- ments by neutron activation. Proc. 15th Coastal Eng. Conf., Am. Soc. Civ. Eng., N.Y. 9. DeFalco, Paul, 1967. The estuary - Septic tank of the megalopolis. In: Estuaries, G.H. Lauff, (ed.), Washington, D.C. 10. Matern, R.A., 1973. San Francisco Bay. In: Our environment the outlook for 1980, (ed.) A.J. Van TassiT. Lexington Books, Lexington, Massachusetts. 11. Serne, R.J. and B.W. Mercer, 1975. Characterization of San Francisco Bay dredged sediments - crystalline matrix study. Appendix F, Dredge Disposal Study, U.S. Army Engineer District, San Francisco, CA. 215 p. -44- 12. Boyd, M.B., R.T. Saucier, J.W. Keeley, R.L. Montgomery, R.D. Brown, D.B. Mathis and C.J. Guice, 1972. Disposal of dredge spoil, prob- lem identification and assessment and research program development. Technical report H-72-8. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. 13. Liu, D.H., K.D. Martin and C.R. Norwood. 1975. San Francisco Bay benthic community study. Dredge Disposal Study, U.S. Army Engineer District, San Francisco, California. Appendix D. 14. Gilbert, G.K. 1917. Hydraulic mining debris in the Sierra Nevada U.S. Geol. Surv. Prof. Pap. 105. 45 p. 15. Nichols, F.H, 1973. A review of benthic fauna! surveys in San Francisco Bay. U.S. Geological Survey, circular 677. 16. Nichols, F.H. 1977. Paper presented at AAAS Meeting, San Francisco State University, June 13, 1977. 17. JBF Scientific Corporation. 1975. Dredging technology study. Dredge Disposal Study, U.S. Army Engineer District, San Francisco, California. Appendix M. 18. San Francisco Bay Conservation and Development Commission, 1976. The Regulation of Dredging. Staff Report. 19. Technical Committee on Criteria for Dredged and Fill Material, 1977. Ecological evaluation of proposed discharge of dredged material into ocean waters. Environmental Effects Laboratory. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. 20. Schubel , J.R. and R.H. Meade, 1975. Man's impact on estuarine sedimentation. I_n: Estuarine Pollution Control and Assessment, Proc. Vol. 1. pp. 193-209. U.S. Environmental Protection Agency, Washington, D.C. 21. Cunnington, E.A., 1968. Survival time of oysters after burial at various temperatures. Proc. Natl. Shelf. Assn., Vol. 58. pp. 101- 103. 22. McCauley, J.E., R.A. Parr and D.R. Hancock, 1977. Benthic infauna and maintenance dredging: a case study. Water Research Vol. 11, pp. 253-242. 23. Oliver, J.S., P.N. Slattery, L.W. Hulberg, and J. W. Nybakken. 1976. Final report task 1D01. Prepared for Environmental Effects Laboratory, DMRP. U.S. Army Engineer Waterways Experiment Station, Vicksburg, MI. 24. Keck, R.T., et al . 1976. Vertical migration of marine benthos in dredged material overburdens. University of Delaware, Coll. Mar. Stud. Draft Report. DMRP Project 1D03. Lewesand Newark, Del. 130 p. -45- 25. No citation. 26. Peddicord, R.K., et al . 1975. Effects of suspended solids on San Francisco Bay organisms. Report to: U.S. Army Corps of Engineers, San Francisco District, Dredge Disposal Study, Appendix G. 158 pp. 27. Peddicord, R.K. and V. McFarland. 1976. Effects of suspended dredged material on aquatic animals. Working draft final report task 1D09. Prepared for U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MI. 28. U.S. Army Engineer District, San Francisco Corps of Engineers. 1976. Water column. Dredge disposal study. Appendix C. 29. Sherk, J. A., J.M. O'Conner and D.A. Neumann, 1975. Effects of sus- pended and deposited sediments on estuarine environments. In: Estuarine Research, ed., L. Eugene Cronin, Vol. 2, pp. 541-3F8. 30. Cronin, L.E., et al . , 1970. Gross physical and biological effects of overboard spoil disposal in upper Chesapeake Bay. Nat. Res. Inst. Spec. Rep. No. 3. University of Maryland. 31. Sullivan, B.K. and D. Hancock, 1977. Zooplankton and dredging: research perspectives from a critical review. Water Res. Bulletin, Vol. 13, No. 3, pp. 461-467. 32. Diaz, R.J. and D.F. Boesch, 1977. Impact of unconfined overboard disposal of fine grained dredged material on benthic communities with particular attention to the environmental effects of fluid mud. Unpublished report task No. 1D12. Environmental Effects Laboratory. U.S. Army Engineer Waterways Experiment Station, Vicksburg, MI. 33. Chen, K.Y. et al . 1976. Research study on the effect of dispersion, settling and resedimentation on migration of chemical constituents during open-water disposal of dredge material. Prepared for U.S. Army Engineer Waterways Experiment Station, Vicksburg, MI. 221 pp. 34. Lu, J.C.S. and K.Y. Chen. 1977. Migration of trace metals in interfaces of seawater and polluted surficial sediments. Environ. Sci. Techno!. 11: 174-182. 35. Anderlini, V.C. et al . 1976. Pollutant availability study. Dredge Disposal Study, U.S. Army Engineer District, San Francisco, CA. 305 pp. Appendix I. 36. Anderlini, V.C. et al . 1975. Heavy metal uptake study. Dredge Disposal Study, U.S. Army Engineer District, San Francisco, CA. 89 pp. Appendix H. -46- 37. Neff, J.W., R.S. Foster and J.F. Slowey. 1977. Research study to determine the availability of sediment adsorbed heavy metals to benthos with particular emphasis on deposit feeding infauna. Interim report task 1D06. Prepared for Environmental Effects Laboratory, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MI. 38. Fulk, R. , D. Gruber and R. Wullschleger. 1975. Laboratory study of the release of pesticides and PCB materials to the water column during dredging and disposal operations. Prepared for U.S. Army Engineer Waterways Experiment Station, Vicksburg, MI. 88 pp. 39. DiSalvo, Louis H. , H.E. Guard, N. Hirsch and J. Ng. 1977. Assess- ment and significance of sediment associated oil and grease in aquatic environments. Draft final report Task 1-D-ll. Prepared for U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MI. 40. DiSalvo, L.H. and H.E. Guard. 1975. Hydrocarbons associated with suspended particulate matter in San Francisco Bay waters. Proc. of American Petroleum Institite, Washington, D.C. 41. Meadows, P.S. and J.G. Anderson. 1968. Microorganisms to marine sand grains. J. Mar. Biol. Assn. U.K. 48: 161-175. 42. Van Donsel , D.J. and E.E. Geldreich. 1971. Relationships of Salmonellae to fecal col i forms in bottom sediments. Water Res. 5: 1079-1087. 43. Grimes, D.J. 1975. Release of sediment bound fecal col i forms by dredging. Appl . Microbiol. 29(1): 109-111. 44. Sawyer, T,K., G.S. Visvesvara, and B.A. Harke. 1977. Pathogenic amoebas from brackish and ocean sediments, with a description of Acanthamoeba hatchetti , n. sp. Science 196: 1324-1325. 45. Lee, G. Fred. 1975. Significance of chemical contaminants in dredged sediments on estuarine water quality. Proc. Estuarine Pollut. Workshop, Pensacola. U.S. Environmental Protection Agency. 46. International Engineering Co. 1975. Final Report: Dredge Spoils Disposal Facility, Skaggs Is. (for) Dept. of the Navy, WEST DIV Naval Facilities Engineering Command, San Bruno, CA. -47- APPENDIX A (References 3) CONCLUSIONS Based on the results of the various investigations conducted during the Dredge Disposal Study (reported in Appendices A through M) the following conclusions have been formulated regarding San Francisco Bay maintenance dredging and disposal activities: o Higher concentrations of contaminants in dredged channels can be attributed to the finer grain size associated with maintenance dredging. Since dredged channels are out of equilibrium, forming lower energy regime, finer sediments will tend to shoal. High contaminant levels in San Francisco Bay are normally associated with the finer sediments. o The type of sediment and the degree to which it is disturbed de- termine the amount of sediment resuspension during dredging and the immediate release pattern during disposal at open water sites. The disturbance, including the adding and mixing with water, de- pends on the type and size of dredge, the efficiency of operation and the configuration of the shoal. o The disturbance during sediment disposal is limited to the bottom two meters of the water column regardless of whether the sediment mounds or disperses. With hopper dredge operations, the sediments leave the disposal site typically within fifteen minutes of re- lease and are quickly assimilated into the Bay sediment regime. o The sediment regime of the Bay is a very dynamic system. Tests in the Bay Area show that within a month, dredged sediments are well distributed both horizontally (over 260 square kilometer study area) and vertically (in excess of 23 centimeters). About ten percent of the dredged sediment returns to the Mare Island Strait channel with disposal in Carquinez Strait. The majority of samples in the study area had less than four percent dredged sediment. Sediments entering San Pablo Bay for the most part are not carried directly to the ocean. Sediments are deposited, resuspended, recirculated and redeposited elsewhere with a net effect of sediment transport toward the ocean. o Dredging and disposal in the Bay were not observed to cause changes in conductivity/salinity, temperature or pH. Temporary but marked water quality changes which were observed included reduction of dissolved oxygen, increases in suspended solids, and releases of trace elements, chlorinated hydrocarbon and nitrogen (nitrate and ammonia). -48- o Although large changes in water quality were demonstrated, no analogous changes in organisms were observed. Thus biological impact was not found to be synonymous with measurable water quality impact. o Significant demonstrated biological effects resulting from in Bay dredging and disposal activities are limited to the reduc- tion of the number and kinds of benthic organisms immediately following an operation and the net reduction of the p, p'-DDE desorption rate during disposal. o The potential for adverse biological stresses from reduced dis- solved oxygen and increased suspended solids concentrations is less during winter periods when water temperatures are lowest and dissolved oxygen levels highest. Furthermore, during this period eggs, larvae and juvenile organisms are at their lowest numbers in the water column. o Release of toxicants during dredging and disposal operations seems to be at such low levels and to last for such short dura- tions that their availability for uptake and accumulation is extremely limited. o Salinity increases significantly intensify the potential for release of certain trace elements from resuspended sediments. Organisms, however, have been observed to have greater uptake rates during periods of decreased salinity and to have greater depuration rates in high salinity water. These two opposing conditions suggest that there is potentially a natural defense mechanism operating in organisms to safeguard them from ex- cessive trace element accumulation. o Increasing the efficiency of dredging operations in terms of minimizing energy losses in disturbing sediments and maximiz- ing the collection of sediments whether by hydraulic cutter- head, clamshell or hopper dredge, will decrease the potential for adverse impacts. o Increasing the dispersion of sediments dredged by hopper dredge in the Bay could have several positive effects. First, the potential of concentrated high suspended solids loading would be reduced. Second, both the intensity and duration of dis- solved oxygen depressions would be reduced. Since these two conditions work synergistically, adverse biological effects would decrease. Third, since both toxicant release and uptake are concentration dependent, greater dispersion, although in- creasing the contact area of sediments for contaminant releases, should reduce the potential maximum release (concentration) at any one location and thus the potential organism uptake and accumulation. And finally, any nutrient or ammonia release -49- would be quickly assimilated into the system, reducing potential localized biostimulation or toxicity. Changes in operational policies would have to be accomplished without significantly in- creasing the time frame of impact. Otherwise, possible mitiga- tive advantages might be offset by increasing the duration of impact. o The potential for long-term accumulation of contaminants by organisms from sediments dredged in harbor areas and disposed in the open bay is and has been a significant biological con- cern because of historically high contaminant levels in these harbor areas. Other areas in the Bay also have equally high contaminant levels because of their predominantly fine grain composition and high transport rate of resuspended sediments. Fine grain sediments naturally scavenge contaminants and wherever they are concentrated, contaminant levels will typi- cally be high. Source control is the only effective method for controlling contaminant levels in these sediments. How- ever, channel sediment sampling during the last two years (1975-1976) seems to indicate that the contaminant levels in dredged channels have decreased to levels congruent with open areas of the Bay. This is probably the result of the elimi- nation or improvement in quality of industrial and municipal discharges as required by both State and Federal regulatory agencies. As Bay sediment contaminant levels decrease, so will the potential for long-term toxicant accumulation. o Open water disposal is not considered a significant blockage of the channels for mitigation of fish, particularly through Carquinez Strait. The plume, as monitored in the field, is confined to the bottom two meters of the water column, and its cross-section constitutes less than one percent of the Carquinez Strait cross-section. The plume occurs in the dis- posal site less than one-quarter of the time (ratio of dis- posal time to total time). o The movement of dredged sediments into the nodal zone in Carquinez Strait should cause no more impact on striped bass finger! ings and neomysis than those sediments naturally oc- curring in this zone. Sediment loading in the nodal zone is dependent on tidal forces and freshwater inflow. Dredged sediments to replace other sediments in the zone; however, unless a contaminant source significantly raises the concen- trations in the dredged sediment, the two sediments should be physically and chemically similar. o The transport of highly contaminated sediments from the Bay to deep water ocean disposal sites has the potential for creating long-term biological impact. When these sediments are released, mounding will generally occur (typically these sediments are cohesive and dredged by clamshell operation). These mounds will remain intact for long periods because of the lack of high -50- current velocities to erode and disperse them. Since these con- taminated sediments typically contain concentrations of organic materials, as well as toxicants, several factors higher than am- bient levels, animals may be attracted to them as a concentrated food source. While feeding, these organisms are susceptible to uptake and accumulation of associated toxicants. This could be a particularly significant problem in the Gulf of the Farallones, a known nursery area for many commercially important species. o The evaluation of potential impacts with with either dispersion or mounding must be made on a case-by-case basis, considering the release of contaminants, the type of sediment and the sen- sitivity of both the water and the sediment system at the dis- posal site. o Extensive land disposal for maintenance dredging projects does not appear to be a viable alternative to aquatic disposal at this time because of costs, identified technical difficulties and adverse environmental effects which may be involved. Po- tential problems include crossing of wetlands, rupture of dikes with earthquakes, mudflows, saline water loading and loss of irretrievable potential wetlands. o Marsh development using dredged sediments should be viable on a case-by-case basis, particularly for one time only, small dredging projects which are located near suitable diked low lands, because of the environmental benefits achieved. Marshes are important to the estuary for their ability to oxygenate Bay waters, produce nutrients which serve as a base for the food web, capture ions, dissipate energy and provide wildlife habitat. o Contaminant levels in estuarine organisms appear to be con- trolled by a limited number of synergistic factors. Suggested factors are the long-term process of sediment resuspension- recirculation, seasonal fluctuations in salinity and sources of contaminants both anthropogenic and geologic. The biolog- ical impact may be dependent on the form of contaminant and whether or not the sediment system can assimilate the contami- nant loading. With the observed sorption-desorption by orga- nisms and the fluctuating conditions in the estuary, impacts such as high accumulations, mutations and toxicity would not be expected unless the contaminant loading is foreign, in the case of synthetic chemicals, or above the assimilation capa- bility of the estuary with the associated sediment regime, in the case of a low energy regime in which the changes in ambient conditions are great. -51- APPENDIX B LIST OF EXPERTS CONTACTED Type of Individual Organization Contact Dr. Richard Peddicord Dr. P.J. Hannan Dr. Teng-Chung Wu Dr. Donald Girvin Mr. L. Thomas Tobin Mr. Mike Rugg Dr. Jim Sutton Mr. Bill Light Mr. William Leet Mr. Fred Minckler Mr. Robert Parker Mr. Ted Durst Mr. Chris Vais Waterways Experiment Station PI Army Corps of Engineers Vicksburg, Mississippi Naval Research Laboratory ph Washington, D.C. Regional Water Quality Control PI Board Oakland, California Lawrence Berkeley Laboratory, ph U.C. Berkeley San Francisco Bay Conservation PI and Development Commission San Francisco, California California State Department of PI Fish and Game Yountville, California California Academy of Sciences PI San Francisco, California National Oceanic and Atmospheric PI Administration (National Marine Fisheries Service), Tiburon, California U.S. Army Corps of Engineers PI Seattle District Office Seattle, Washington U.S. Environmental Protection PI Agency, Region IX San Francisco, California Key PI = Personal Interview ph = Telephone Contact APPENDIX B LIST OF EXPERTS CONTACTED (Continued) Individual Organization Type of Contact Dr. H.L. Taten Dr. Robert Engler Dr. Bill Barnard Mr. John Sustar Dr. T.J. Conomos Mr. Charles Roberts Mr. Bob Tasto Mr. Phil Swartzell Waterways Experiment Station, Army Corps Vicksburg, Mississippi San Francisco District Corps of Engineers U.S. Geological Survey Menlo Park, California San Francisco Bay Conservation and Development Commission San Francisco, California California Department of Fish and Game Menlo Park, California PI PI ph ph PI -53-