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Bioaccumulation of Pollutants in California Waters: A Review of Historic Data and Assessment of Impacts on Fishing and Aquatic Life

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Bioaccumulation of Pollutants in California Waters: A Review of Historic Data and Assessment of Impacts on Fishing and Aquatic Life
California State Water Resources Control Board, San Francisco Estuary Institute | October 24, 2007...
Summary
This report was written for the State Water Resources Control Board’s Surface Water Ambient Monitoring Program (SWAMP) as a step toward the development...

This report was written for the State Water Resources Control Board’s Surface Water Ambient Monitoring Program (SWAMP) as a step toward the development of an improved bioaccumulation monitoring program for California. The report provides a review of bioaccumulation monitoring data generated under three historic State Board programs (the Toxic Substances Monitoring Program, the State Mussel Watch Program, and the Coastal Fish Contamination Program) and other major bioaccumulation studies since 1970. Future monitoring will be guided by assessment questions developed for the SWAMP. The objective of this report was to evaluate how well the historic data from the State Board programs and from other major monitoring efforts since 1970 address these questions. This exercise has provided a substantial amount of information about present and historical impacts of pollutant bioaccumulation on shing and aquatic life in California, and has also highlighted areas where improved sampling approaches can better address the assessment questions.

Present concentrations of pollutants in many California water bodies are high enough to cause concern for possible effects on human health and to have a significant impact on the fishing beneficial use. Consumption advisories, 303(d) listings, and the bioaccumulation database as a whole provide three indices of the status of this impact. Consumption advisories exist for an increasing number of water bodies, but these represent only a fraction of the areas likely to need them. Lack of suitable data is a major impediment to developing advice for additional water bodies. A US E.P.A. evaluation of the 2002 303(d) List indicated that large portions of the state had not been assessed, especially rivers and coastline. Most of the lake area in the state (61%) had been assessed, and a relatively small percentage of the total area (6%) was classified as impaired. Assessment of lakes, however, has focused primarily on the largest lakes, leaving the vast majority of smaller lakes unsampled. Many of these small lakes are near population centers and are popular for shing. Bays and estuaries had been thoroughly assessed (98% of the area) and 93% of the total area was impaired.

Evaluation of the most recent monitoring data (collected from 1998-2003) indicates that, for the locations sampled, 32% had low concentrations of pollutants, 42% had moderate concentrations, 18% had high concentrations, and 8% had very high concentrations (Figure 1). Concentrations in the low category are in a range where consumption is generally encouraged by the California Office of Environmental Health Hazard Assessment (OEHHA) (Klasing and Brodberg 2006). OEHHA is the agency responsible for managing health risks due to contaminated sport fish in California. Concentrations in the very high category are in a range where OEHHA discourages consumption (Klasing and Brodberg 2006). Lakes assigned to the moderate, high, or very high concentration categories were primarily affected by mercury, with PCBs also playing a lesser role.

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California Bay – Delta Authority Fish Mercury Project: The Relationship between Landscape Features and Sport Fish Mercury in the Sacramento-San Joaquin Delta Watershed
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California Bay – Delta Authority Fish Mercury Project: The Relationship between Landscape Features and Sport Fish Mercury in the Sacramento-San Joaquin Delta Watershed
San Francisco Estuary Institute | November 2, 2007...
Summary
The goal of this study was to quantify the relationship between landscape features and mercury in sport fish. We hypothesized that spatial variation...
The goal of this study was to quantify the relationship between landscape features and mercury in sport fish. We hypothesized that spatial variation in sport fish mercury would most strongly relate to major point sources associated with mining activity, habitat features (e.g., abundance of wetlands), and watershed-scale patterns in mercury deposition from the atmosphere.

Geographic information system (GIS) techniques were used to evaluate the influence of these features on the bioaccumulation of mercury in sport fish. In addition, we attempted to determine the most appropriate spatial scale for analysis of these influences. Fish mercury data were selected from a state-wide historical bioaccumulation database, which also included data collected by the Fish Mercury Project (FMP) in 2005. Based on the geographic distribution of the sampling locations, three species common across the study area were chosen for analysis: largemouth bass, channel catfish, and white catfish. For the time interval examined (1990 – 2005), the mean wet weight concentration for each species at a given location was calculated.

By superimposing hydrologic flow paths with watershed delineations, we were able to determine flow direction and pathways from upstream sources to downstream habitats. “Fish watersheds” (watershed areas upstream of fish sampling locations) were created for a subset of locations in the CalFed Ecosystem Restoration Program Geographic Scope. Regions heavily influenced by mining within each watershed were also delineated. We examined landscape features in fish watersheds and within close proximity (circular buffers) of fish locations. Using a GIS database, several statistics were derived for each fish watershed area and buffer, including the percent covered by habitat features (vegetated vs. non-vegetated wetlands, permanent vs. temporary inundation), number of gold and mercury mines, total land area (km2), and total length (km) of all streams and rivers.

The work presented in this report is the first attempt the authors are aware of to relate landscape features to fish mercury concentrations using GIS on a large regional scale. Fish mercury concentrations appeared to be influenced by many complex and interacting factors that obscured any obvious correlations with atmospheric deposition, historic mining districts, and wetlands at the watershed scale. Some features seemed to have an influence at the proximal-scale (buffer) analyses, namely vegetated wetland and temporarily inundated aquatic habitat. Though these tentative conclusions were based on small sample sizes, they contradicted the prevailing notion that wetlands generally increase methylmercury accumulation in the food web.

The lack of clear relationships in the dataset analyzed is probably due to shortcomings in the available data, rather than a true absence of influence of atmospheric deposition, mining, or wetlands on spatial patterns in mercury bioaccumulation. Future attempts to relate landscape features with mercury in the food web at the watershed scale should focus on watersheds with a stronger linkage between landscape features and mercury in fish and fewer confounding factors. Statewide monitoring of sport fish is currently being planned that should provide a better basis for conducting this type of analysis in the future.

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Coagulant and Sorbent Efficacy in Removing Mercury from Surface Waters in the Cache Creek Watershed, California

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Coagulant and Sorbent Efficacy in Removing Mercury from Surface Waters in the Cache Creek Watershed, California
U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (EPA) | February 25, 2019...
Summary
Cache Creek drains part of northern California’s Coast Ranges and is an important source of mercury (Hg) to the Sacramento–San Joaquin Delta. Cache...

Cache Creek drains part of northern California’s Coast Ranges and is an important source of mercury (Hg) to the Sacramento–San Joaquin Delta. Cache Creek is contaminated with Hg from several sources, including historical Hg and gold mines, native Hg in the soils, and active mineral springs. In laboratory experiments in a study conducted by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, the use of coagulants and sorbents to immobilize Hg in water samples from high- concentration sources in the Cache Creek watershed was investigated. Three sites were selected for the collection of surface-water samples containing high and low concentrations of particulate-associated Hg. The high-particulate Hg samples were collected from Cache Creek Settling Basin duringstormflow conditions. The low-particulate Hg samples werecollected from two geochemically contrasting sites duringbase-flow conditions (downstream from a geothermal springand at the emergence point of a connate-water spring).

Three coagulants were chosen for laboratory testing with the high-particulate sample— (1) ChitoVanTM HV 1.5 percent (shell based), (2) FerralyteTM 8131 (ferric sulfate based), and (3) UltrionTM 8186 (aluminum based). Each coagulant was tested at various dose amounts to determine the optimum dose rate for the high-particulate sample. The low-particulate source samples were passed through three sorbents—

(1) chitosan flakes, (2) coconut shell-based activated carbon,and (3) coal-based activated carbon. In-line columns were packed with each material, and the untreated sample waspassed through each column at three different flow rates (0.1,0.5, and 1.0 liter per minute, L/min).

For dose rates used in this study, ChitoVanTM reduced turbidity of the particulate sample by 85–91 percent, FerralyteTM reduced turbidity by 54–93 percent, and UltrionTMreduced turbidity by greater than 90 percent. At the lowest dose rate, ChitoVanTM achieved a 59- to 61-percent reduction in whole-water methylmercury (MeHg) concentrations and a 71- to 75-percent decrease in whole-water total mercury (THg) concentrations. FerralyteTM achieved a 37- to 48-percent decrease in whole-water MeHg concentrations and a 37- to 48-percent reduction in whole-water THg concentrations. UltrionTM achieved a greater than 90-percent decrease in whole-water MeHg and THg concentrations.

Mercury removal from the low-particulate samples was less efficient for the sorbent materials compared to the coagulants; less than 30 percent of THg was removed from any 500-milliliter aliquot using sorbent materials. The coal-based sorbent was the most versatile of the sorbents, removing THg to a similar extent from both low-particulatesource waters. The chitosan sorbent was the most effective atremoving THg from the low-particulate stream sample, but less effective for the low-particulate connate-spring sample. The Hg removal efficiency of the coconut sorbent decreasedquickly compared to the other two sorbents, indicating that sorption may be limited by the short contact times evaluated in this study.

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Contaminant Concentrations in Sport Fish from San Francisco Bay: 2014
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Contaminant Concentrations in Sport Fish from San Francisco Bay: 2014
San Francisco Estuary Institute | January 1, 2014...
Summary
This summary report presents results from a 2014 survey of contaminants in San Francisco Bay sport fish, as well as an additional 2015...
This summary report presents results from a 2014 survey of contaminants in San Francisco Bay sport fish, as well as an additional 2015 sampling of sport fish in Artesian Slough in Lower South Bay. This monitoring effort represents the seventh round of sport fish contaminant monitoring conducted by the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP). This technical report is intended for agency staff charged with managing water quality issues related to bioaccumulation of contaminants in San Francisco Bay.

The RMP began sport fish monitoring in 1997, following a pilot study conducted by the Bay Protection and Toxic Cleanup Program in 1994. Data collected through this monitoring program provides updates on the status and long-term trends of contaminants in Bay sport fish, and are used to update human health consumption advisories and evaluate the effectiveness of regulatory and management efforts to reduce the impacts of contaminants of concern in the Bay.

Key analyses in this report include comparisons of concentrations to human health and regulatory thresholds, spatial trend evaluation, and temporal trend evaluation.

Mercury, polychlorinated biphenyls (PCBs), dioxins, selenium, polybrominated diphenyl ethers (PBDEs), and perfluoroalkylated substances (PFASs) were analyzed across sixteen fish species collected at eight locations in San Francisco Bay and Artesian Slough.

Fish species were selected based on a number of criteria, including species that are popular for consumption, are sensitive indicators of problems (accumulating relatively high concentrations of contaminants), are widely distributed, represent different exposure pathways (benthic vs. pelagic), and have been monitored in the past. Concentrations were compared to numeric human health thresholds established by the California Office of Environmental Health Hazard Assessment (OEHHA) for mercury, PCBs, selenium, and PBDEs. Results were also compared to regulatory thresholds for mercury, PCBs, and selenium, as well as non-regulatory screening value for dioxins, which have been established in Total Maximum Daily Load (TMDL) regulations by the San Francisco Bay Regional Water Quality Control Board (Water Board).

The OEHHA fish consumption advisory is primarily driven by human exposure risks to mercury and PCBs. The 2014 data show that mercury and PCB concentrations remain high and widespread, indicating that these contaminants continue to pose the greatest human and wildlife health risks. Mercury concentrations exceeded OEHHA’s no consumption threshold for the sensitive population (women 18-45 and children 1-17) in several white sturgeon and striped bass samples, while PCB concentrations exceeded the no consumption threshold in Pacific sardine and white sturgeon samples. The spatial distribution of contamination has remained consistent over time, reflecting current knowledge of contaminated source areas targeted for management activities. Recent data showed no clear evidence of Bay-wide declines in either mercury or PCBs, although progressively lower PCB concentrations have been observed in recent years near Berkeley and in San Pablo Bay.

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Contaminant Effects on California Bay-Delta Species & Human Health
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Contaminant Effects on California Bay-Delta Species & Human Health
San Francisco Estuary & Watershed Science (UC Davis) | December 1, 2016...
Summary
Many contaminants in the California Bay-Delta exceed regulatory standards, impact aquatic species, and potentially affect human health. Recent studies provide evidence that contaminants...
Many contaminants in the California Bay-Delta exceed regulatory standards, impact aquatic species, and potentially affect human health. Recent studies provide evidence that contaminants impact species of concern in the Bay-Delta (e.g., the decline of several important fish species referred to as the “Pelagic Organism Decline”). Multiple chemicals impair processes at cellular and physiological levels (measured as growth, development, and behavior abnormalities), ultimately affecting populations.

As an important example, the population decline of the endangered delta smelt (Hypomesus transpacificus) is significantly associated with multiple stressors, including insecticide use. New analyses presented in this paper show significant correlations between pyrethroid (an insecticide) use and declining abundance of POD fish species.

Water sampled from the Bay-Delta causes multiple harmful effects in fish and delta smelt. Fish prey items are also impacted by contaminants; this may have an indirect effect on their populations. Co-occurrence with thermal changes or disease can worsen contaminant effects.

Contaminants also pose threats to human health via consumption of fish, drinking water, and contact recreation, in particular, mercury, toxins, disinfection byproducts, pesticides, pharmaceuticals, and personal care products. The role of contaminants in the decline of Bay-Delta species is difficult to accurately assess in a complex, dynamic system. However, tools and approaches are available to evaluate contaminant impacts on Bay-Delta species, and separate the effects of multiple stressors. Integrated monitoring and focused mechanistic studies are instrumental for addressing management needs. Impact and risk assessments should be conducted for different species across multiple life stages, with emphasis on early life stages of high-priority Bay-Delta species.

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DRERIP Ecosystem Conceptual Model: Chemical stressors
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DRERIP Ecosystem Conceptual Model: Chemical stressors
California Department of Fish and Wildlife (CDFW) | February 5, 2008...
Summary
The Sacramento-San Joaquin Delta ecosystem comprises many different habitat types, and is home to a large number of species. Thousands of chemical contaminants...
The Sacramento-San Joaquin Delta ecosystem comprises many different habitat types, and is home to a large number of species. Thousands of chemical contaminants have been or are being introduced into the Delta. The conceptual model presented here is therefore general in nature, and is intended to provide a framework for more refined models for individual species, habitats and, in particular, contaminants of interest, for example selenium, mercury and pyrethroids.

The model consists of three major submodels (Figure 1). Submodel 1: Exposure assessment which includes fate and transport of contaminants and the co-occurrence of chemicals with Delta organisms; the intermediate outcome of this submodel is “Exposure Concentration”. Submodel 2: Bioavailability of contaminants to Delta organisms; the intermediate outcome of this submodel is “Bioavailable Concentration” or “Dose”. Submodel 3: Toxic effects assessment with the final model outcome “Population Level Effects”.

In the following narrative, we provide a description for each submodel, its parameters, and linkages to other models. We discuss the model’s limitations and provide recommendations for its application in management.

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DRERIP Ecosystem Conceptual Model: Mercury
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DRERIP Ecosystem Conceptual Model: Mercury
California Department of Fish and Wildlife (CDFW) | January 24, 2008...
Summary
Mercury has been identified as an important contaminant in the Delta, based on elevated concentrations of methylmercury (a toxic, organic form that readily...
Mercury has been identified as an important contaminant in the Delta, based on elevated concentrations of methylmercury (a toxic, organic form that readily bioaccumulates) in fish and wildlife. There are health risks associated with human exposure to methylmercury by consumption of sport fish, particularly top predators such as bass species. Original mercury sources were upstream tributaries where historical mining of mercury in the Coast Ranges and gold in the Sierra Nevada and Klamath-Trinity Mountains caused contamination of water and sediment on a regional scale. Remediation of abandoned mine sites may reduce local sources in these watersheds, but much of the mercury contamination occurs in sediments stored in the riverbeds, floodplains, and the Bay-Delta, where scouring of Gold-Rush-era sediment represents an ongoing source.

Conversion of inorganic mercury to toxic methylmercury occurs in anaerobic environments including some wetlands. Wetland restoration managers must be cognizant of potential effects on mercury cycling so that the problem is not exacerbated. Recent research suggests that wetting-drying cycles can contribute to mercury methylation. For example, high marshes (inundated only during the highest tides for several days per month) tend to have higher methylmercury concentrations in water, sediment, and biota compared with low marshes, which do not dry out completely during the tidal cycle. Seasonally inundated flood plains are another environment experiencing wetting and drying where methylmercury concentrations are typically elevated.

Stream restoration efforts using gravel injection or other reworking of coarse sediment in most watersheds of the Central Valley involve tailings from historical gold mining that are likely to contain elevated mercury in associated fines. Habitat restoration projects, particularly those involving wetlands, may cause increases in methylmercury exposure in the watershed. This possibility should be evaluated.

The DRERIP mercury conceptual model and its four submodels (1. Methylation, 2. Bioaccumulation, 3. Human Health Effects, and 4. Wildlife Heath Effects) can be used to understand the general relationships among drivers and outcomes associated with mercury cycling in the Delta. Several linkages between important drivers and outcomes have been identified as important but highly uncertain (i.e. poorly understood). For example, there may be significant wildlife health effect of mercury on mammals and reptiles in the Delta, but there is currently very little or no information about it. The characteristics of such linkages are important when prioritizing and funding restoration projects and associated monitoring in the Delta and its tributaries.

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Environmental Health Risks from Abandoned Mines in the Sierra Nevada
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Environmental Health Risks from Abandoned Mines in the Sierra Nevada
The Sierra Fund | June 9, 2014...
Summary
The widespread pollution from Gold Rush mining activities, including mercury, arsenic and lead, constitutes the oldest and longest neglected environmental justice problem in...
The widespread pollution from Gold Rush mining activities, including mercury, arsenic and lead, constitutes the oldest and longest neglected environmental justice problem in California. The effects of this pollution on human health and the environment are only now beginning to be addressed.

Today, the effects of historic mining pollution are an invisible but very real threat to people who live, work or recreate in the Sierra Nevada. Toxins of concern include mercury, arsenic, lead and asbestos. There is little information about these potential exposures available to Sierra residents. State-issued fish consumption advisories in the region
do not provide site-specific advice for many locations people fish, or the species people eat.

In 2006, The Sierra Fund, in partnership with California State University Chico, conducted a survey of Sierra clinics. This study found that not one of 13 surveyed clinics included information on mercury in fish as part of their maternal/infant health programs, whether caught locally or not. Additionally, the study learned that none of the clinics surveyed administer an environmental health history form, so it is difficult to connect current health problems to environmental exposures.

In order to address this lack of information and provide a springboard for more research, The Sierra Fund conducted three pilot studies of potential environmental exposures in 2009 and 2010 and a pilot outreach program to present these findings to Sierra communities in 2013-14. This report summarizes findings and recommendations from these efforts, in order to encourage continued research into these potentially serious health exposures.

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Estimating Exposure of Piscivorous Birds and Sport Fish to Mercury in California Lakes Using Prey Fish Monitoring—A Predictive Tool for Managers

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Estimating Exposure of Piscivorous Birds and Sport Fish to Mercury in California Lakes Using Prey Fish Monitoring—A Predictive Tool for Managers
U.S. Geological Survey (USGS) | May 22, 2015...
Summary
Numerous water bodies in California are listed under the Clean Water Act as being impaired due to mercury (Hg) contamination. The Surface Water...
Numerous water bodies in California are listed under the Clean Water Act as being impaired due to mercury (Hg) contamination. The Surface Water Ambient Monitoring Program (SWAMP), via the Bioaccumulation Oversight Group (BOG), has recently completed statewide surveys of contaminants in sport fish tissue from more than 250 lakes and rivers in California and throughout coastal waters. This effort focused on human health issues but did not include beneficial uses by wildlife. Many piscivorous birds such as grebes, terns, cormorants, and mergansers eat fish smaller than those that were sampled by BOG, and sport fish Hg concentrations are not always indicative of wildlife exposure to Hg; therefore, the BOG surveys could not address whether wildlife were at risk due to Hg-induced reproductive impairment in these lakes.

We used western grebes (Aechmophorus occidentalis) and Clark’s grebes (Aechmophorus clarkii) as our index of wildlife exposure to Hg in California lakes. Grebes are widely distributed in lakes throughout California and, as piscivorous waterbirds, are near the top of the food chain in lakes. Additionally, grebes become flightless after they arrive at their summer locations. Thus, grebes are useful representatives for wildlife risk from local, lake-specific contaminant exposure. Grebes also breed at many lakes throughout California, making them susceptible to impaired reproduction due to local Hg contamination.

We developed a tool for estimating wildlife and sport fish risk from Hg exposure based on Hg concentrations in prey fish. This quantitative tool can be used to predict Hg concentrations in grebe blood, grebe eggs, and sport fish, thus facilitating a feasible alternative for adequately estimating wildlife exposure when more comprehensive wildlife sampling is not possible. Specifically, we sampled grebes, prey fish, and sport fish simultaneously at 25 lakes throughout California during the spring and summer of 2012 and 2013 when breeding birds are particularly vulnerable to Hg-induced reproductive impairment. We selected lakes based on a combination of factors, including lakes
1. from southern and northern California,
2. of various sizes, shapes, and elevations,
3. with a range of sport fish Hg exposure levels
4. where largemouth bass (Micropterus salmoides) was the primary sport fish, and
5. with a history of use by grebes.
Using these factors ensured that our results are representative of a broad range of lakes and reservoirs in California and are comparable to prior BOG studies.

Specifically, we addressed three management questions:
1. Does methylmercury pose significant risks to aquatic life in a representative sample of California lakes and reservoirs?
2. Can a correlational approach be applied on a statewide basis to estimate risks to birds?
3. What are appropriate water-quality monitoring requirements to address methylmercury exposure in wildlife?
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Land Use, Pollutants, and Water Quality in California Streams

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Land Use, Pollutants, and Water Quality in California Streams
California State Water Resources Control Board | April 12, 2012...
Summary
A number of spatial patterns were evident in this survey of watersheds from throughout California. Stream sediment concentrations of heavy metals, such as...

A number of spatial patterns were evident in this survey of watersheds from throughout California. Stream sediment concentrations of heavy metals, such as cadmium, copper, lead and zinc, tended to be highest in urbanized Los Angeles and San Francisco Bay area watersheds. Metal concentrations in sediments from San Leandro Creek (SF Bay area), Ballona Creek and San Gabriel River (Los Angeles area) were among the highest in the state. These metals are released to the environment from brake pads, plumbing, industrial and commercial activities. Industrial organic compounds such as PCBs (banned since the 1970s), PBDEs (flame retardants) and PAHs (hydrocarbons) were also generally highest in stream sediments from the Los Angeles and San Francisco Bay areas, though high concentrations were also measured in some more remote locations.

In contrast to this urban pattern, mercury concentrations were highest in sediments from watersheds where it is geologically abundant and historically mined, though some urban streams also had relatively high mercury levels. The persistent legacy pesticide DDT was found in stream sediments from most urban and agricultural watersheds, where recent soil disturbance from development and tillage likely mobilizes DDT residues from applications more than 40 years ago. Pyrethroid pesticides are increasing in use in California and were detected in 55% of the samples statewide (51 of 92). The highest pyrethroid concentrations were measured in sediments collected from urban watersheds, plus two agricultural watersheds along the central coast. Approximately one quarter of the sediment samples collected were significantly toxic to amphipods, which are resident crustaceans representative of important aquatic food web links. Of these samples, 6.5% were identified as highly toxic. The highly toxic samples were collected from agricultural watersheds in the Tulare basin and central coast, in urban areas of southern California, and in the Tijuana River. Other toxic samples were collected from a wide range of watershed types, including those along the north coast, the Tahoe area, and urban and agricultural areas across the state.

On a statewide basis, watersheds with greater than 10% urban land cover had consistently higher sediment pollutant concentrations and toxicity than did watersheds characterized by agricultural or other land cover types. Metals, industrial compounds, DDTs, and pyrethroid pesticides were all found at significantly higher concentrations in urban streams. This pattern is evident at the statewide level, but other local and regional studies have previously shown that pollution levels and toxicity can be strongly related to agricultural and other land uses in specific areas. This is because the “agricultural” land use category used in the SPoT analysis is comprised of many different types of crops and farming practices, and the amount of polluted runoff from these lands varies depending on the types of practices employed.

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