RMP NewsVolume 1, Issue 2

Regional Monitoring News, Fall 1995

Contents

PCBs in the San Francisco Estuary

RMP Monitoring Basics

Fish Contamination

Teaching About Watersheds Conference

Staff Contacts

Evaluating the Ecological Health of the Estuary

Staff Profile: Bruce E. Thompson

Calendar

Announcements

The ABCs of PCBs in the San Francisco Estuary

by Jay Davis

Polychlorinated biphenyls (PCBs) are a class of contaminants that are currently of great concern in the Estuary. RMP results from 1994 show that PCB concentrations in waters of the Estuary are uniformly greater than an EPA water quality criterion. In addition, a study conducted by the San Francisco Bay Regional Water Quality Control Board in 1994 found that PCB concentrations in fish collected throughout the Bay exceeded screening values for protection of human health, resulting in the issuance of an advisory for consumption of Bay fish. 

These recent findings are surprising in light of the fact that PCBs have been unavailable commercially and subject to restricted uses for almost two decades. How can PCBs still be a problem in the Estuary? The answer to this question lies in a combination of the extreme persistence of these compounds, their biomagnification in the food web, continuing sources, and careless disposal in the past that has led to widespread contamination on both a local and global scale. 

Sources of PCBs

Due to their resistance to electrical, thermal, and chemical processes, PCBs were used in a wide variety of applications from the time of their initial commercial production in 1929. The primary uses of PCBs were as insulating materials in electrical capacitors and transformers, hydraulic fluids, plasticizers in rubber and synthetic resins, carbonless copy paper, and lubricants. Smaller quantities were used as pesticide extenders and in inks, waxes, and other applications. In 1966 came the first report that PCBs were widespread environmental contaminants. By the 1970s a growing appreciation of the severity and ubiquity of environmental PCB contamination led to restrictions on PCB production and use. Commercial production of PCBs in the U.S. ceased in 1977. 

The Estuary has served as a receptacle for a significant quantity of PCB residues. A detailed inventory of the sources of PCBs to the San Francisco Estuary has not been compiled. In general, major sources of PCBs to the environment have included industrial sites, direct emissions in periods with less stringent emission guidelines than are currently in place, and landfills which improperly received PCB-contaminated waste. Currently a major source of PCBs to surface waters is remobilization or redeposition of residues in soil, sediment, or the atmosphere. Due to the extreme persistence of PCBs this mobile environmental reservoir will only diminish slowly. Potential sources of "fresh" PCBs still exist. According to a 1981 estimate, 58% of the total quantity of PCBs manufactured were either still in use or not yet disposed of. At present, the quantity of PCBs remaining in place at the original site of application or still requiring disposal is unknown. 

A recent incident at Dunsmuir Reservoir in Alameda County demonstrates how accidental releases of PCBs can occur in local watersheds, leading eventually to PCB loading to the Estuary. Joint caulking installed in the basins of this reservoir in the late 1960s contained 15-20% PCBs. Replacement of this caulking, which began in 1992, led to release of PCBs to San Leandro Creek, where concentrations as high as 500 parts per million were measured in sediment. Remediation of this contamination is being performed. 

Regional Monitoring Program (RMP) data indicate that PCB concentrations are elevated in the South Bay (from Yerba Buena Island south) and somewhat elevated in the northern Estuary, but does not provide any strong indication of sources of PCBs. Detailed analysis of the profile, or mixture, of PCBs present in RMP samples may provide information on sources of PCB contamination in the Estuary. PCB profiles will be analyzed and results presented in the 1995 RMP Annual Report. 

Fate of PCBs in the Estuary

The physical and chemical properties of PCBs determine their fate in waters of the Estuary. PCBs are generally much more soluble (dissolve to a greater extent) in organic material than in water. A typical PCB molecule has a maximum aqueous solubility on the order of only 10 µg/l and is approximately 10 million times more soluble in the fat of living organisms than in water. PCBs, therefore, generally have a strong tendency to move out of the water column and into living organisms. This process of movement from one portion of the ecosystem to another is called "partitioning". 

PCBs are generally resistant to chemical and biochemical transformations in the environment. Microbial degradation of PCBs, although slow, is probably the ultimate degradation process for PCBs in sediment. Although some PCBs are also metabolized by higher organisms, many pass largely unmetabolized through the food web. Due to their resistance to metabolism and high affinity for lipid, PCBs reach higher concentrations with increasing trophic level in aquatic environments; this process is known as "biomagnification". 

RMP data from the Estuary illustrate the processes of partitioning and biomagnification (Figure 1). The median concentration of dissolved PCBs in water in 1994 was 0.000341 ppb (parts per billion). The median concentration in the particulate fraction of water samples was 3.5-fold greater (0.001197 ppb), demonstrating the tendency of PCBs to associate with particles. Median concentrations in sediment (6 ppb) were 18,000 times higher than concentrations dissolved in water. Bivalve tissue had still higher concentrations (61 ppb), 179,000 times higher than dissolved in water. PCB concentrations in fish muscle tissue from the Bay were determined in the Regional Board's fish contamination study. Although whole body concentrations would be most appropriate for illustrating biomagnification, typical concentrations in muscle were on the order of 100 ppb, 293,000 times higher than dissolved in water. Appropriate PCB data on fish predators in the Estuary for comparison with these data are not available. Data from elsewhere suggest, however, that concentrations in top predators would be much greater still. Herring gulls on Lake Ontario, for example, accumulate whole body PCB concentrations (on the order of 100,000 ppb) that are 100-200 times the concentration in Lake Ontario fish and 100 million times the PCB concentration in water. 

  
Figure 1. Typical PCB Concentrations in the Estuary. 
 

PCB Effects in the Estuary 

Certain PCBs are extremely toxic in chronic exposures. The most toxic PCBs are those that closely mimic the potency and mechanism of toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (commonly known as "dioxin", one of the most toxic compounds known). These PCBs can cause toxic symptoms similar to those caused by dioxin exposure, including developmental abnormalities, disruption of the endocrine system, impairment of immune function, and cancer promotion. The extreme chronic toxicity of PCBs resulted in the small magnitude of the EPA criterion for PCB concentrations in saltwater (44 parts per quadrillion, or 0.000044 ppb). This concentration was exceeded at all RMP saltwater stations in 1994. 

In acute exposures, on the other hand, PCBs are not exceptionally toxic. The most sensitive species of fresh- and saltwater fish and invertebrates exhibit acute toxicity at aqueous concentrations as low as 1 ppb. Threshold concentrations for sublethal effects on aquatic species are indicated by "maximum acceptable toxicant concentrations" developed by EPA, which were as low as 0.16 ppb in an early life stage test with sheepshead minnows. The highest total PCB concentration measured in water in the 1994 RMP was 0.009 ppb, well below concentrations known to result in direct acute toxicity to aquatic organisms. 

In sediments, PCBs are mostly partitioned onto surfaces of mineral particles or into particulate organic material. However, low concentrations may exist in pore water between the particles. Biological effects may begin in association with PCB sediment concentrations above about 22.7 ppb. Fourteen sediment samples (out of twenty) from RMP stations were above that value in 1994. 

Due to the biomagnification of PCBs in the food web, predatory fish, birds, and mammals (including humans that consume fish) at the top of the food web are particularly vulnerable to the effects of PCB contamination. Several studies have indicated that PCB contamination of the food web may be severe enough to adversely affect either humans or wildlife species that consume fish caught in the Estuary. As mentioned above, the Regional Board's fish contamination study found that PCB concentrations in samples collected throughout the Bay exceeded EPA screening values based on protection of human health and resulted in the issuance of an advisory for consumption of Bay fish. RMP findings that PCB concentrations in waters of the Estuary are uniformly greater than EPA's human health-based water quality criterion are consistent with the high concentrations found in Bay fish and the resultant advisory. 

PCB concentrations at the top of the food web may also be high enough to elicit effects on sensitive life stages of Bay biota. Studies in the 1980s suggested that PCBs were adversely affecting reproduction in starry flounder and black-crowned night herons. In research conducted in 1991 and 1992 some harbor seals were found to have whole blood PCB concentrations that were more than double concentrations associated with reproductive effects and immune dysfunction in harbor seals in the Netherlands. Another study employed a biomarker (cytochrome P450) that is responsive to the dioxin-like compounds, including the dioxin-like PCBs, to assess pollutant accumulation and effects in double-crested cormorant embryos on the Bay. Data from 1993 and 1994 suggest that median concentrations of dioxin-like compounds in Bay embryos are at the threshold for toxic effects in this species. The pollutant profile in Bay fish implicates PCBs as the primary compounds likely to be inducing cytochrome P450 in embryos of the fish-eating cormorants. 

Trends in PCB Contamination

PCB concentrations in the Estuary appear to be diminishing very slowly. Under the State Mussel Watch Program, PCB concentrations in mussels have been measured on nearly an annual basis since 1980 at two locations in the Bay: Pinole Point and Treasure Island. PCB concentrations at these locations declined between 1980 and 1982. The apparent magnitude of this decline is exaggerated in Figure 2 due to unusually high concentrations in 1981. PCB concentrations were high in mussels throughout the Bay in 1981, suggesting either a major input or redistribution of PCB residues in that year. Since 1982, however, PCB concentrations in mussels have remained relatively constant. Under the RMP, PCB concentrations in mussels have been measured at many locations in the Bay in 1993 and 1994, including Pinole Point and Yerba Buena Island, two locations near the State Mussel Watch locations. Although the RMP data are from different laboratories and based on different techniques for quantifying PCBs, they are probably underestimates relative to the State Mussel Watch data. While a high degree of year-to-year variation is characteristic of the Estuary and obscures interpretation of trends, there appears to be no evidence of decreasing PCB concentrations in the past 10 years. 

  
 
Figure 2. PCBs in Mussels. 
 

These data indicate that the current level of PCB contamination in the food web of the Estuary is likely to persist for some time. While a significant amount of this contamination is due to remobilization of historical deposits, some is probably also due to continuing fresh inputs and transport from contaminated portions of the Estuary's watershed. Through better characterization of the nature of PCB contamination in the Estuary it may be possible to determine whether controllable sources still exist. Efforts along these lines have been initiated as part of the 1995 RMP. 
 

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RMP Monitoring Basics

by Michael May

In the last newsletter, Margaret Johnston described the origin of the RMP and touched on its management structure. This article will provide a brief overview of the monitoring program itself. 

What is being sampled?

The Regional Monitoring Program currently collects samples from up to 25 locations throughout the Estuary. Samples taken include: 
 

• Estuary water
• Estuary sediment
• Tissue from bivalves (clams, oysters, and mussels)
• Mussel condition (volume and length)
• Estuarine benthic (bottom-dwelling) organisms
• Tidal wetland sediment
• Tidal wetland benthic organisms

What is being measured?

Water samples are analyzed for basic parameters such as salinity, dissolved oxygen, and pH; for contaminants such as heavy metals (e.g. mercury) and organic compounds (e.g. DDT). Sample water is also used in toxicity tests, in which laboratory organisms (e.g. mussel and oyster larvae and shrimp) are exposed to the sample for a fixed time period. Organism death and growth rates and developmental abnormalities are recorded as indicators of toxicity. 

Water sampling currently takes place three times each year, allowing seasonal trends in the data to be examined. Sampling occurs during the rainy season in March, during the period of declining Delta outflow in May, and during the dry season in September. 

Sediment samples undergo analysis similar to that for water samples. Basic parameters such as grain-size and pH are measured, and metal and organic contaminant analysis is performed. Toxicity testing is performed in two ways: in one test, an estuarine amphipod is exposed to sampled sediment, and mortality is recorded. The second test exposes larval bivalves to a water solution derived from the sediments; abnormal development and mortality are measured. Sediment sampling takes place twice each year, in March and September. 

Bivalves are transplanted from less contaminated regions such as Bodega Head (mussels), or Tomales Bay (oysters), or Lake Isabella (freshwater clams), and are deployed in plastic mesh bags at Estuary stations for 90 days. At the end of the deployment period, the bivalves are recovered and their tissue is measured for trace metal and organic contaminants. Bivalve tissue analyses are performed because they provide an indication of how Estuary contaminants are being incorporated into estuarine life. This is particularly important, as bivalves and other Estuary life can accumulate contaminants over time, resulting in internal contaminant concentrations much higher than concentrations found in the surrounding water. 

Shell length and volume are also measured on a portion of the recovered bivalves, as these measurements can be an indicator of bivalve response to Estuary conditions. Bivalves are deployed for ninety days twice a year, from February to May, and from June to September. 

In addition to these primary monitoring activities, the RMP also supports two other types of related activities, known as pilot studies and special studies. 

Pilot studies are studies that are under evaluation for potential incorporation into the RMP monitoring program. Currently, the wetland monitoring portion of the RMP is a pilot study. As with the estuarine sediments, wetland sediments, both from tidal channels and from the marsh plain, are analyzed for metals and organic contaminants. The kinds and numbers of benthic organisms found in tidal channel sediments are also recorded. Other pilot studies investigate hydrology and suspended sediments in the Estuary. 

Special studies are studies that will help interpret RMP data better, or that help make better RMP measurements. Special studies that have been supported include investigating optimal monitoring sampling design, the question of which ecological indicators the RMP should be using, and long term trends in trace metal concentrations. 
 

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Fish Contamination: Whither RMP?

by Margaret Johnston

In the fall of 1994, the Regional Water Quality Control Board released a draft report, Contaminant Levels in Fish Tissue from San Francisco Bay, and the Office of Environmental Health Hazard Assessment (OEHHA) almost simultaneously released new health advisories. A final version of the fish tissue report was released by the Board in June of 1995. 

This study found that six chemicals exceeded screening levels in fish tissue: PCBs (total Aroclors), mercury, dieldrin, total chlordanes, total DDTs and total dioxin/furans. 

PCBs were nearly ubiquitous in the fish tissue samples; mercury was also elevated in the majority of samples. 

RMP data from water, sediment, and transplanted bivalves tends to support the findings of the fish contamination study: 
 

• High concentrations of PCBs were found in water throughout the Bay.
• Sediment samples showed concentrations of mercury, DDTs and PCBs above the "Effects Range-Low" or ERL, meaning there is a possibility for ecological effects.
• Bioaccumulation of mercury, DDTs, PCBs, dieldrin and chlordanes (among other chemicals) in transplanted bivalve tissue were noted at some sites.

The Regional Board considers their fish contamination study to be preliminary, with additional work needed to more precisely define the extent of contamination. It has been suggested that additional workat a cost of about $1,000,000˜be done through the RMP. The Regional Board has listed as priorities for additional research the following: examine seasonal variation in contamination levels; identify additional chemicals and additional species to be analyzed; and standardize techniques for better comparison of contamination levels among species and among Estuary sites. 

Questions about the ecological effects of contaminants on the fish and the predators that consumed the fish (other than humans) have also been raised. Dischargers have suggested that information gathered should lead to a control strategy. For example, since PCBs are persistent, and also have been banned for many years, are the concentrations measured today a result of inputs from many years ago? If there are indeed current sources of pollution, what are they, and how can they be reduced or eliminated? 

The Regional Board, RMP Steering Committee, and SFEI are currently discussing how to take the next step towards understanding the nature and extent of fish contamination in the Estuary. 

Whether fish contamination studies will continue to be conducted by the Regional Board or whether the RMP process will be used to develop further studies is being discussed. The development of funding and technical study strategies are also being considered. All participants agree that further study is needed; it is hoped that the ongoing discussion will lead to a thoughtful approach to studying and managing contaminants that meets the needs of both the dischargers and the Regional Board. 
 

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Teaching About Watersheds Conference

On November 4, 1995, 250 educators attended the Teaching About Watersheds conference at California State University, Hayward. Along with attending the morning plenary sessions, teachers were able to choose from over twenty afternoon workshops with subjects ranging from Raising Aquatic Critters in the Classroom to Implementing a Riparian Inventory Project. In addition, nearly 200 educators participated in a variety of field trips to investigate watersheds around the Bay Area which were offered on Sunday, November 5, and the following weekend, November 11 and 12. 

More than 135 organizations supported Teaching About Watersheds, thus allowing the registration fee to remain low for the sixth year in a row. Approximately 16,000 students benefited from this year's conference. 

The San Francisco Estuary Institute and the Department of Biological Sciences/School of Science at California State University Hayward would like to offer a sincere thanks to the following Regional Monitoring Program sponsors that supported the Teaching About Watersheds conference: the City of Oakland, the City of Palo Alto, Las Gallinas Valley Sanitary District, Central Contra Costa Sanitary District, the Port of Oakland, Dow USA, Novato Sanitation District, the East Bay Dischargers Association, the City of South San Francisco, the East Bay Municipal Utilities District, and the City of San Jose. 
 

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SFEI Staff Internet Addresses and Telephone Extensions

The main line at the Institute is (510) 430-0801 
 

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Evaluating the Ecological Health of the Estuary: How Do We Get from Here to There?

by Rainer Hoenicke, Ph.D.

Remember the Regional Monitoring Strategy? As a companion document to the Comprehensive Conservation and Management Plan for the Estuary, the Strategy was developed to: 

• assess the effectiveness of management actions that have been taken to improve conditions in the Estuary and to protect its resources,
• evaluate the ecological health of the Estuary, and
• enhance scientific understanding of the ecosystem.

The San Francisco Estuary Institute was founded to implement the strategy and is currently working in several areas recommended by the CCMP. 

The Regional Monitoring Program for Trace Substances represents a step in this direction. After two years of data collection, SFEI staff members realized that making sense out of the thousands of data points so far collected is a daunting task that takes more time and brain cells than we have available here at the Institute. The idea arose that, in order to make this program truly "participatory," we should offer Program Participants, University staff, scientists from regulatory and resource management agencies, and others opportunities to contribute their expertise directly in transforming data into relevant information. 

Many talented scientists, environmental engineers, land use planners, etc. are working within their respective organizations on projects relevant to the evaluation of Estuary health, but do not find the time to put their work into this context or fit their individual puzzle pieces into a coherent picture. One approach that occurred to us is the initiation of a 'sabbatical program' that RMP Participants and others could take part in. A six-to twelve-month stay at SFEI would enable experts in relevant fields to dedicate undisturbed time to questions of interest to them and the RMP. A time without the regular administrative and 'emergency-response' duties within their own organization would give experts within the environmental management community a way of re-charging their batteries and at the same time contributing valuable information to the overall scientific understanding about the Estuary. Specifically, contributions to the Annual Report, assisting in development of an "Estuary Contamination Index", and integrating RMP special studies and other related efforts into the RMP picture, among other projects, would be welcomed. 

We would like to hear your responses to this idea in order to begin to work out details at one of the upcoming RMP Steering Committee meetings. Please call Bruce Thompson, Senior Scientist, at (510) 430-0801 x613, with your feedback! 
 

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Annual Meeting

The Annual Meeting of the Regional Monitoring Program will take place on Thursday, December 14, 1995, at the Richmond Field Station. Items to be discussed include the highlights of the 1994 monitoring program, the benthic pilot, results from the indicator workshop, and the wetland pilot. Group or panel discussions include: different ways to create an annual report; the upcoming 1997 program review; and RMP goals and objectives. The meeting will be held in Bldg. 445: registration opens at 9:00, the conference will begin promptly at 9:30, and end at 4:30. Program participants that have RSVP'd will be provided with lunch. Please call Gabbi Marek at (510) 430-0801 x 420 to make your reservation. We look forward to seeing you at the meeting! 
 

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 Staff Profile: Meet Dr. Bruce E. Thompson˜Senior Scientist

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RMP Calendar

December 14. 
RMP Annual Meeting, at SFEI offices on the Richmond Field Station. Please see annoucement on page 7. For more information call (510) 430-0801. 

Announcements

CALLING ALL GRADUATE STUDENTS 

Looking for a research paper topic? The RMP data set now has approximately 80,000 data points involving water quality measurements, trace substance concentrations in water, sediment and bagged bivalves, benthic samples, etc... SFEI staff has only begun to analyze this data set, and numerous types of analyses could be performed. If interested, call Dr. Rainer Hoenicke at (510) 430-0801 x 731. 

San Francisco Estuary Institute
7770 Pardee Lane
Oakland, CA 94621-1424
(510) 746-SFEI (7334)
Fax (510) 746-7300
www.sfei.org