Vaginal matrix metalloproteinase-9 (MMP-9) as a potential early predictor of preterm birth.

OBJECTIVES: To evaluate the differences in vaginal matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMPs) in pregnant patients with a history of prior preterm birth compared with controls. METHODS: A prospective cohort pilot study recruited patients during prenatal care with history of prior spontaneous preterm birth (high-risk group) or no history of preterm birth (low-risk/controls). Inclusion criteria were singleton gestation at 11-16 weeks and between 18 and 55 years of age. Exclusion criteria were diabetes mellitus, hypertension, diseases affecting the immune response or acute vaginitis. A vaginal wash was performed at time of enrollment, and patients were followed through delivery. Samples were analyzed using semi-quantitative analysis of MMPS and TIMPS. The study was approved by the IRB and a p value <0.05 was considered significant. RESULTS: A total of 48 pregnant patients were recruited: 16 with a history of preterm birth (high-risk group) and 32 with no history of preterm birth (low-risk group/controls). Groups were similar in age, race, BMI, and delivery mode. The high-risk group had more multiparous women (100 vs. 68.8 %; p=0.02), a greater preterm birth rate (31.2 vs. 6.3 %; p=0.02), and a lower birth weight (2,885 ± 898 g vs. 3,480 ± 473 g; p=0.02). Levels of vaginal MMP-9 were greater in high-risk patients than low-risk patients (74.9 % ± 27.0 vs. 49.4 % ± 31.1; p=0.01). When dividing the cohort into patients that had a spontaneous preterm birth (7/48, 14.6 %) vs. those with a term delivery (41/48, 85.4 %), the vaginal MMP-9 remained elevated in the cohort that experienced a preterm birth (85.46 %+19.79 vs. 53.20 %+31.47; p=0.01). There were no differences in the other MMPS and in TIMPs between high and low-risk groups. CONCLUSIONS: There was an increase in vaginal MMP-9 during early pregnancy in those at high risk for preterm birth and in those who delivered preterm, regardless of prior pregnancy outcome. Vaginal MMP-9 may have potential as a marker of increased risk of preterm birth.

Psychological measures of patient's decision-making for prenatal genetic testing.

OBJECTIVE: To use a questionnaire to determine the levels of maternal decision-related distress, clarity of the pros and cons, and certainty when considering prenatal genetic diagnostic testing; and to assess the relationship between these constructs and patient characteristics. METHOD: Cross-sectional study. Voluntary, anonymous questionnaires distributed 2017-2019 to women referred for invasive prenatal genetic testing. Excluded: English or Spanish illiterate. Maternal characteristics were collected. Questions evaluated distress, decisional certainty, and decisional clarity on a 5-point Likert scale (range: 0 = low/uncertain/unclear to 4 = high/certain/clear). Analysis: non-parametric Kruskal-Wallis, correlation statistics, and ANOVA. RESULTS: Forty-four female patients completed it. Most were married, white, Catholic, and multiparous. 58% had already made a testing decision. Patients expressed low distress levels (mean 1.18 ± 0.80) and expressed high decisional certainty (mean 3.28 ± 0.76) and clarity (mean 3.30 ± 0.99). Decisional certainty and clarity were positively correlated (r = 0.47, p < .01), whereas distress was negatively correlated with decisional certainty (r = -0.8136, p < .0005) and decisional clarity (r = -0.49, p = .007). No significant differences by religion or parity. Greater distress (p < .05) and less decisional clarity (p = .07) occurred between those still debating testing vs those who had decided. CONCLUSIONS: Higher maternal distress scores were associated with lower decisional certainty and decisional clarity in women considering prenatal genetic testing.

Comparison of buprenorphine and methadone in the management of maternal opioid use disorder in full term pregnancies.

Objectives To compare pregnancy outcomes with medication assisted treatment using. methadone or buprenorphine in term mothers with opioid use disorder. Methods A cohort of women receiving medication assisted treatment with either methadone or buprenorphine were identified from delivery records over a 10-year period. Women were excluded with delivery <37 weeks, multiple gestations, or a known anomalous fetus. Maternal demographics, medications, mode of delivery, birthweight, newborn length of stay, and neonatal abstinence syndrome were extracted. The study was IRB approved and a p-value of <0.05 was significant. Results There were 260 women, 140 (53.8%) with methadone use and 120 (46.2%) with buprenorphine use. Groups were similar for maternal age, race, parity, homeless rate, tobacco use, mode of delivery and incidence of neonatal abstinence syndrome. The methadone group had a lower mean newborn birthweight (2874±459 g) and a greater incidence of low birth weight (11.4%) than the buprenorphine group (3282±452 g; p<0.001 and 2.5%; p=0.006). The incidence of neonatal abstinence syndrome was similar between groups (97% methadone vs. 92.5% buprenorphine; p=0.08). The methadone group had a longer newborn length of stay (11.4+7.4 days) and more newborn treatment with morphine (44.6%) than the buprenorphine group (8.2+4.4 days; p<0.001 and 24.2%; p<0.001). Maternal methadone use was an independent predictor for a newborn length of hospital stay >7 days (OR 3.61; 95% confidence interval 1.32-9.86; p=0.01). Conclusions Medication assisted treatment favors buprenorphine use when compared to. methadone with an increased birthweight, reduced need for newborn treatment, and a shorter newborn length of stay in term infants.

Factors influencing methylmercury contamination of black bass from California reservoirs.

Understanding how mercury (Hg) accumulates in the aquatic food web requires information on the factors driving methylmercury (MeHg) contamination. This paper employs data on MeHg in muscle tissue of three black bass species (Largemouth Bass, Spotted Bass, and Smallmouth Bass) sampled from 21 reservoirs in California. During a two-year period, reservoirs were sampled for total Hg in sediment, total Hg and MeHg in water, chlorophyll a, organic carbon, sulfate, dissolved oxygen, pH, conductivity, and temperature. These data, combined with land-use statistics and reservoir morphometry, were used to investigate relationships to size-normalized black bass MeHg concentrations. Significant correlations to black bass MeHg were observed for total Hg in sediment, total Hg and MeHg in surface water, and forested area. A multivariate statistical model predicted Largemouth Bass MeHg as a function of total Hg in sediment, MeHg in surface water, specific conductivity, total Hg in soils, and forested area. Comparison to historical reservoir sediment data suggested there has been no significant decline in sediment total Hg at five northern California reservoirs during the past 20 years. Overall, total Hg in sediment was indicated as the most influential factor associated with black bass MeHg contamination. The results of this study improve understanding of how MeHg varies in California reservoirs and the factors that correlate with fish MeHg contamination.

Long-term variation in concentrations and mass loads in a semi-arid watershed influenced by historic mercury mining and urban pollutant sources.

Urban watersheds are significantly anthropogenically-altered landscapes. Most previous studies cover relatively short periods, without addressing concentrations, loads, and yields in relation to annual climate fluctuations, and datasets on Ag, Se, PBDEs, and PCDD/Fs are rare. Intensive storm-focused sampling and continuous turbidity monitoring were employed to quantify pollution at two locations in the Guadalupe River (California, USA). At a downstream location, we determined loads of suspended sediment (SS) for 14yrs., mercury (HgT), PCBs, and total organic carbon (TOC) (8yrs), total methylmercury (MeHgT) (6yrs), nutrients, and trace elements including Ag and Se (3yrs), DDTs, chlordanes, dieldrin, and PBDEs (2yrs), and PCDD/Fs (1yr). At an upstream location, we determined loads of SS for 4yrs. and HgT, MeHgT, PCBs and PCDD/Fs for 1yr. These data were compared to previous studies, climatically adjusted, and used to critically assess the use of small datasets for estimating annual average conditions. Concentrations and yields in the Guadalupe River appear to be atypical for total phosphorus, DDTs, dieldrin, HgT, MeHgT, Cr, Ni, and possibly Se due to local conditions. Other pollutants appear to be similar to other urban systems. On average, wet season flow varied by 6.5-fold and flow-weighted mean (FWM) concentrations varied 4.4-fold, with an average 7.1-fold difference between minimum and maximum annual loads. Loads for an average runoff year for each pollutant were usually less than the best estimate of long-term average. The arithmetic average of multiple years of load data or a FWM concentration combined with mean annual flow was also usually below the best estimate of long-term average load. Mean annual loads using sampled years were also less than the best estimate of long-term average by a mean of 2.2-fold. Climatic adjustment techniques are needed for computing estimates of long-term average annual loads.

Mercury in western North America: A synthesis of environmental contamination, fluxes, bioaccumulation, and risk to fish and wildlife.

Western North America is a region defined by extreme gradients in geomorphology and climate, which support a diverse array of ecological communities and natural resources. The region also has extreme gradients in mercury (Hg) contamination due to a broad distribution of inorganic Hg sources. These diverse Hg sources and a varied landscape create a unique and complex mosaic of ecological risk from Hg impairment associated with differential methylmercury (MeHg) production and bioaccumulation. Understanding the landscape-scale variation in the magnitude and relative importance of processes associated with Hg transport, methylation, and MeHg bioaccumulation requires a multidisciplinary synthesis that transcends small-scale variability. The Western North America Mercury Synthesis compiled, analyzed, and interpreted spatial and temporal patterns and drivers of Hg and MeHg in air, soil, vegetation, sediments, fish, and wildlife across western North America. This collaboration evaluated the potential risk from Hg to fish, and wildlife health, human exposure, and examined resource management activities that influenced the risk of Hg contamination. This paper integrates the key information presented across the individual papers that comprise the synthesis. The compiled information indicates that Hg contamination is widespread, but heterogeneous, across western North America. The storage and transport of inorganic Hg across landscape gradients are largely regulated by climate and land-cover factors such as plant productivity and precipitation. Importantly, there was a striking lack of concordance between pools and sources of inorganic Hg, and MeHg in aquatic food webs. Additionally, water management had a widespread influence on MeHg bioaccumulation in aquatic ecosystems, whereas mining impacts where relatively localized. These results highlight the decoupling of inorganic Hg sources with MeHg production and bioaccumulation. Together the findings indicate that developing efforts to control MeHg production in the West may be particularly beneficial for reducing food web exposure instead of efforts to simply control inorganic Hg sources.

Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada.

Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western United States (US) and Canada, a region defined by extreme gradients in habitat structure and water management. A database was compiled with THg concentrations in 96,310 fish that comprised 206 species from 4262 locations, and used to evaluate the spatial distribution of fish THg across the region and effects of species, foraging guilds, habitats, and ecoregions. Areas of elevated THg exposure were identified by developing a relativized estimate of fish mercury concentrations at a watershed scale that accounted for the variability associated with fish species, fish size, and site effects. THg concentrations in fish muscle ranged between 0.001 and 28.4 (µg/g wet weight (ww)) with a geometric mean of 0.17. Overall, 30% of individual fish samples and 17% of means by location exceeded the 0.30µg/g ww US EPA fish tissue criterion. Fish THg concentrations differed among habitat types, with riverine habitats consistently higher than lacustrine habitats. Importantly, fish THg concentrations were not correlated with sediment THg concentrations at a watershed scale, but were weakly correlated with sediment MeHg concentrations, suggesting that factors influencing MeHg production may be more important than inorganic Hg loading for determining fish MeHg exposure. There was large heterogeneity in fish THg concentrations across the landscape; THg concentrations were generally higher in semi-arid and arid regions such as the Great Basin and Desert Southwest, than in temperate forests. Results suggest that fish mercury exposure is widespread throughout Western US and Canada, and that species, habitat type, and region play an important role in influencing ecological risk of mercury in aquatic ecosystems.

Declines in polybrominated diphenyl ether contamination of San Francisco Bay following production phase-outs and bans.

California has implemented unique consumer product flammability standards. Polybrominated diphenyl ether (PBDE) flame retardants were once widely incorporated into products to meet these standards, but concerns regarding toxicity and accumulation in humans and biota led to nationwide phase-outs and state bans. A decade of PBDE monitoring in San Francisco Bay has resulted in a data set that covers periods during and after PBDE use and consists of hundreds of measurements of water, sediment, and biota. While PBDEs remain widely detected in biota, levels have declined by nearly half in sport fish and 74-95% in bivalves and bird eggs. Concentrations of BDE-47 in sediment have dropped by over one-third from 2002 to 2012; in water, a decline is not yet evident. The dominant congener in sediment, DecaBDE component BDE-209, showed no temporal trend. U.S. production of DecaBDE ended in 2013; future monitoring may reveal declines. Overall, the data indicate that reduced production can result in relatively rapid reductions in the concentrations of some hydrophobic contaminants in biota and sediment, particularly when implemented after only a few decades of heavy use. Recent changes to California's flammability standards may lessen the use of other flame retardants and similarly reduce Bay contamination.

Mussel Watch update: long-term trends in selected contaminants from coastal California, 1977-2010.

This study examined trends in contaminants measured during three decades of "Mussel Watch" monitoring on the California coast. Chlorinated organic contaminants and butyltins declined the most rapidly, with tissue concentrations in 2010 that were up to 75% lower than during the 1980s. Silver and lead declined at about half of the stations statewide, but generally exhibited slower rates of decline relative to the organic compounds. In contrast, copper increased at many stations, and PAHs showed little evidence for declines. Mussels from San Francisco Bay and the Southern California Bight were historically the most contaminated and have had the steepest declines. Overall, these data show that the "Mussel Watch" approach to monitoring contaminants in California has provided some of the best evidence of the effectiveness of actions to improve water quality over the past 30 years. These datasets also highlight challenges that remain in managing PAHs and copper.

Water quality in South San Francisco Bay, California: current condition and potential issues for the South Bay Salt Pond Restoration Project.

The SBSPRP is an extensive tidal wetland restoration project that is underway at the margin of South San Francisco Bay, California. The Project, which aims to restore former salt ponds to tidal marsh and manage other ponds for water bird support, is taking place in the context of a highly urbanized watershed and an Estuary already impacted by chemical contaminants. There is an intimate relationship between water quality in the watershed, the Bay, and the transitional wetland areas where the Project is located. The Project seeks to restore habitat for endangered and endemic species and to provide recreational opportunities for people. Therefore, water quality and bioaccumulation of contaminants in fish and wildlife is an important concern for the success of the Project. Mercury, PCBs, and PBDEs are the persistent contaminants of greatest concern in the region. All of these contaminants are present at elevated concentrations both in the abiotic environment and in wildlife. Dioxins, pyrethroids, PAHs, and selenium are also problematic. Organochlorine insecticides have historically impacted the Bay, and they remain above thresholds for concern in a small proportion of samples. Emerging contaminants, such as PFCs and non-PBDE flame retardants, are also an important water quality issue. Beyond chemical pollutants, other concerns for water quality in South San Francisco Bay exist, and include biological constituents, especially invasive species, and chemical attributes, such as dissolved oxygen and salinity. Future changes, both from within the Project and from the Bay and watershed, are likely to influence water quality in the region. Project actions to restore wetlands could worsen, improve, or not affect the already impaired water quality in South Bay. Accelerated erosion of buried sediment as a consequence of Project restoration actions is a potentially serious regional threat to South Bay water and sediment quality. Furthermore, the planned restoration of salt ponds to tidal marsh has raised concerns about possible increased net production of methylmercury and its subsequent accumulation in the food web. This concern applies not only to the restored marshes, but also to the South Bay as a whole, which could be affected on a regional scale. The ponds that are converted to tidal marsh will sequester millions of cubic meters of sediment. Sequestration of sediment in marshes could remove contaminated sediment from the active zone of the Bay but could also create marshes with contaminated food webs. Some of the ponds will not be restored to marsh but will be managed for use by water birds. Therefore, the effect of dense avian populations on eutrophication and the introduction of pathogens should be considered. Water quality in the Project also could be affected by external changes, such as human population growth and climate change. To address these many concerns related to water quality, the SBSPRP managers, and others faced with management of wetland restoration at a regional scale, should practice adaptive management and ongoing monitoring for water quality, particularly monitoring bioaccumulation of contaminants in the food web.

Contaminant concentrations and histopathological effects in Sacramento splittail (Pogonichthys macrolepidotus).

Sacramento splittail (Pogonichthys macrolepidotus) is a species of special concern in California, due to multiple anthropogenic stressors. To better understand the potential impact of contaminant exposure, adult splittail were captured from the Sacramento-San Joaquin River Delta (California, USA) and analyzed for histopathology and contaminant exposure. Organochlorine contaminants (PCBs, DDTs, dieldrin, chlordanes, and PBDEs) and trace metals (Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sn, V, and Zn) were detected in the tissues of all fish. In many samples, human health screening values were exceeded for PCBs (83 of 90 samples), DDTs (32 samples), and dieldrin (37 samples). In contrast, thresholds for fish effects were rarely exceeded. Histopathological analysis indicated the presence of macrophage aggregates in gonads, kidneys, and liver and a high incidence of liver abnormalities. In the liver, observed effects were often moderate to severe for glycogen depletion (55 of 95 fish), lipidosis (hepatocellular vacuolation; 51 fish), and cytoplasmic inclusion bodies (33 fish). Correlations between histopathology and tissue contaminant concentrations were weak and inconsistent. Significant correlations were observed between histopathology indicators and reductions in fish size, body condition, lipid content, and liver weight. These results suggest that splittail histopathology varies as a function of health and nutritional status, rather than exposure to legacy organic and metal pollutants.

Mercury in sport fish from the Sacramento-San Joaquin Delta region, California, USA.

Total mercury (Hg) concentrations were determined in fillet tissue of sport fish captured in the Sacramento-San Joaquin River Delta and surrounding tributaries, a region particularly impacted by historic gold and mercury mining activity. In 1999 and 2000, mercury concentrations were measured in 767 samples from ten fish species. Largemouth bass (Micropterus salmoides), the primary target species, exhibited a median Hg concentration of 0.53 mug g(-1) (N=406). Only 23 largemouth bass (6%) were below a 0.12 mug g(-1) threshold corresponding to a 4 meals per month safe consumption limit. Most of the largemouth bass (222 fish, or 55% of the sample) were above a 0.47 mug g(-1) threshold corresponding to a 1 meal per month consumption limit. Striped bass (Morone saxatilis), channel catfish (Ictalurus punctatus), white catfish (Ameirus catus), and Sacramento pikeminnow (Ptychocheilus grandis) also had relatively high concentrations, with 31% or more of samples above 0.47 mug g(-1). Concentrations were lowest in redear (Lepomis microlophus) and bluegill (Lepomis macrochirus) sunfish, with most samples below 0.12 mug g(-1), suggesting that targeting these species for sport and subsistence fishing may reduce human dietary exposure to Hg in the region. An improved method of analysis of covariance was performed to evaluate spatial variation in Hg in largemouth bass captured in 2000, while accounting for variability in fish length. Using this approach, Hg concentrations were significantly elevated in the Feather River, northern Delta, lower Cosumnes River, and San Joaquin River regions. In spite of elevated Hg concentrations on all of its tributaries, the central Delta had concentrations that were low both in comparison to safe consumption guidelines and to other locations.

The slow recovery of San Francisco Bay from the legacy of organochlorine pesticides.

The use of organochlorine pesticides, including DDTs, chlordanes, and dieldrin, peaked in San Francisco Bay's watershed 30-40 years ago, yet residues of the pesticides remain high. Known as legacy pesticides for their persistence in the Bay decades after their uses ended, the compounds and their breakdown products occur at concentrations high enough to contribute to advisories against the consumption of sport fish from the Bay. Combined with other data sets, the long-term monitoring data collected by the San Francisco Estuary Regional Monitoring Program (RMP) for trace substances allow us to track recovery of the Bay from these inputs and predict its future improvement. Legacy pesticides enter the water and sediment of San Francisco Bay from a variety of sources, including runoff from California's Central Valley and local watersheds, municipal and industrial wastewater, atmospheric deposition, erosion of historically contaminated sediment deposits, and dredging and disposal of dredged material. Runoff from small-urbanized tributaries may contribute as much or more to the loads than runoff from the agricultural Central Valley, even though 90 percent of the freshwater flow comes from the Central Valley via the Sacramento and San Joaquin rivers. The fates of legacy pesticides in San Francisco Bay are controlled by their chemical properties, including their solubilities and partition coefficients. Degradation in the sediments, outflow through the Golden Gate, and volatilization-in that relative order-result in removal of pesticides from the Bay. A contaminant fate model was used to estimate recovery times of the Bay under various scenarios. For example, under a scenario in which no new legacy pesticides entered the Bay, model predictions suggested that concentrations of pesticides in the water and the active sediment layer would reach risk-reduction goals within one to three decades. Under scenarios of continued inputs to the Bay, recovery time would be considerably longer or not reached at all. Long-term tissue monitoring corroborates model predictions of slow declines in DDT and chlordane concentrations. Field-transplanted bivalve samples indicate declines since 1980, and lipid-weight concentrations of pesticides have declined in fishes, but the declines are slow. The critical management question for the Bay is whether there are feasible management actions that would decrease concentrations in sport fish significantly faster than the existing slow progress that has been observed.

A PAH fate model for San Francisco Bay.

A mass balance model was applied to simulate the long-term fate of PAHs in San Francisco Bay. The model treats the Bay as a single box with interacting water and sediment compartments, and includes loading, volatilization, outflow to the ocean, degradation, and burial in deep sediment. The estimated time required for loss of one-half of the mass in the Bay in the absence of loading ranged from 20 d for naphthalene to 5 yr for benzo(b)fluoranthene. Uncertainty analysis using Monte Carlo simulation indicated a high degree of influence and uncertainty for degradation rates, suggesting that improved estimates of degradation would significantly improve the predictive ability of the model. A comparison of model calculations to literature values suggested that external PAH loading to San Francisco Bay was at or above previous estimates of 3600 kgyr(-1), and that degradation in the Bay was within the range of commonly published estimates for high molecular weight PAHs (4.0 x 10(-5) to 4.0 x 10(-4)d(-1)).

Seasonal, interannual, and long-term variation in sport fish contamination, San Francisco Bay.

This study documents changes in contamination over time at seasonal, interannual, and decadal time scales for sport fish collected in San Francisco Bay. Samples from seven fish species were prepared according to common consumption practices (muscle fillets either with or without skin) and analyzed for trace metals (mercury and selenium) and trace organochlorine contaminants (PCBs, DDTs, chlordanes, and dieldrin). In 2000, sport fish samples exceeded human health screening values for mercury, PCBs, DDTs, selenium, and dieldrin but did not exceed screening values for chlordanes. On a seasonal time scale, white croaker (Genyonemus lineatus) exhibited significantly lower PCB and lipid concentrations in spring, and a general increase in concentrations in other seasons. When monitoring data were compared among 1994, 1997, and 2000, analysis of variance indicated that concentrations of mercury, PCBs, DDTs, and chlordanes varied significantly among years for several fish species. Interannual variation in DDTs often correlated to changes in sampled fish size or lipid content among years. Interannual variation in mercury and PCBs was evident in striped bass (Morone saxatilis) but absent in shiner surfperch (Cymatogaster aggregata), leopard shark (Triakis semifasciata), and white croaker. The higher interannual variability of striped bass contaminant concentrations may result from migratory behavior and wide home ranges. Chlordanes significantly declined between 1994 and 2000 in white croaker and striped bass. Of the historical data analyzed (1986-2000), only DDT concentrations in white sturgeon (Acipenser transmontanus) showed evidence of a significant decline. Neither PCBs nor selenium showed evidence of a trend in white sturgeon. Between 1970 and 2000, mercury concentrations in striped bass showed no evidence of a trend. The absence of recent trends in mercury may result from the presence of widespread and historic sources, with use reductions occurring in the early 20th century. In contrast to mercury, apparent recent declines in fish tissue DDT and chlordane concentrations may result from use curtailment in the 1970s and 1980s.

The long-term fate of polychlorinated biphenyls in San Francisco Bay (USA).

A simple one-box mass budget model is presented as a first step toward a quantitative understanding of the long-term fate of polychlorinated biphenyls (PCBs) in San Francisco Bay (USA). Sensitivity analysis indicated that the most influential input parameters were degradation half-life in sediment, Kow, outflow, average PCB concentration in sediment, and depth of the active sediment layer. Moderately influential parameters included organic carbon content of suspended solids, sediment burial mass transfer coefficient, and Henry's law constant. If external loading could be eliminated entirely, the mass of PCBs in the bay is predicted to drop to half of the present value in 20 years. The model predicts that sustained loading of 10 kg year(-1) would prevent the total PCB mass in the bay from ever dropping below 10% of the present mass. With a sustained loading of 20 kg year(-1), the model predicts that the total PCB mass would never fall below about 25% of the present mass. The half-lives in the bay for the individual PCB congeners evaluated in this report ranged from four years for PCB 18 to 30 years for PCB 194.

Surveillance for previously unmonitored organic contaminants in the San Francisco Estuary.

The San Francisco Estuary Regional Monitoring Program initiated surveillance monitoring to identify previously unmonitored synthetic organic contaminants in the San Francisco Estuary. Organic extracts of water samples were analyzed using gas chromatography-mass spectrometry in full scan mode. The major contaminant classes identified in the samples were fire retardants, pesticides, personal care product ingredients, and plasticizers. Evidence from the literature suggests that some of these contaminants can persist in the environment, induce toxicity, and accumulate in marine biota and in higher food chain consumers. The major sources of these contaminants into the marine environment are the discharge of municipal and industrial wastewater effluents, urban stormwater, and agricultural runoff. As a proactive effort, it is suggested that surveillance studies be used routinely in monitoring programs to identify and prevent potential problem contaminants from harming the marine environment.

Effective application of monitoring information: the case of San Francisco Bay.

The San Francisco Estuary Regional Monitoring Program (RMP) for Trace Substances is an innovative partnership among a regulatory agency, more than 70 regulated entities, and an independent scientific organization. The institutional arrangement behind the RMP has made the regulatory system increasingly responsive to emerging management needs, particularly with regard to the development of total maximum daily loads and ecosystem impairment assessment. Through multiagency partnerships within and outside the RMP institutional structure, major information gaps for several pollutants of concern have been narrowed, resulting in a successful consensus-based regulatory approach to managing copper and nickel mass inputs into the Estuary. Short-term research efforts, based upon monitoring results, helped identify the most cost-effective control and remediation options for various bioaccumulative substances. Additionally, adaptive changes to the monitoring program documented the existence of widespread aquatic toxicity in the Estuary that is apparently due to pesticide runoff from agricultural and urban areas. One of the most important contributions of this collaborative monitoring program is the deliberate and systematic adjustment of management and research questions that serve to influence and add relevance to the overall research agenda related to San Francisco Estuary ecosystem assessment.

Contaminant concentrations in sport fish from San Francisco Bay, 1997.

In 1997, seven sport fish species were sampled from seven popular fishing areas in San Francisco Bay. Mercury exceeded a human health screening value in 44 of 84 (52%) samples. All collected samples of leopard shark and striped bass exceeded the mercury screening value of 0.23 microg/g wet weight. PCBs exceeded the screening value in 51 of 72 (71%) samples. DDT, chlordane, and dieldrin, had lower numbers of samples above screening values: 16 of 72 (22%) for DDT, 11 of 72 (15%) for chlordanes, and 27 of 72 (37%) for dieldrin. Concentrations of PCBs and other trace organics were highest in white croaker and shiner surfperch, the two species with the highest fat content in their muscle tissue. Fish from one location, Oakland Harbor, had significantly elevated wet weight concentrations of mercury, PCBs, DDTs, and chlordanes compared to other locations. Removal of skin from white croaker fillets reduced lipid concentrations by 27-49% and concentrations of trace organics by 33-40%.