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

Connor, Michael S.; Davis, Jay A; Leatherbarrow, J. E.; Greenfield, B. K.; Gunther, A. J.; Hardin, Dane; Mumley, Thomas; Oram, J. J.; Werme, C.

doi:10.1016/j.envres.2006.07.001

Cited by 41 publications

(29 citation statements)

References 29 publications

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“…Based on FWMCs, storm flow concentrations were 2.5-11 times greater (for HCHs and DDTs, respectively) than low flow concentrations for all of the OC pesticides. Relative to concentrations reported for another San Francisco Bay area watershed (the Guadalupe River, a larger and moderately urban watershed), concentrations of DDTs, chlordanes and dieldrin Z4LA were all much lower (FWMCs for Guadalupe River were 48, 40 and 3.7 ng/l, respectively; Connor et al, 2007). Comparisons were more mixed against concentrations reported in other studies nationally and internationally.…”

Section: Oc Pesticidesmentioning

confidence: 56%

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Concentrations and loads of PCBs, dioxins, PAHs, PBDEs, OC pesticides and pyrethroids during storm and low flow conditions in a small urban semi-arid watershed

Gilbreath

McKee

2015

Science of The Total Environment

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Section: Oc Pesticidesmentioning

confidence: 56%

“…Concentrations of the other commonly used OC pesticides are also still observed (e.g. Zhang et al, 2010;Foster et al, 2000b;Kratzer, 1999;Connor et al, 2007). Like PCBs, loading data are sparse and little information is available for concentrations and loads found in semi-arid watersheds.…”

Section: Introductionmentioning

confidence: 96%

Concentrations and loads of PCBs, dioxins, PAHs, PBDEs, OC pesticides and pyrethroids during storm and low flow conditions in a small urban semi-arid watershed

Gilbreath

McKee

2015

Science of The Total Environment

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“…The model was initially developed by Davis [6] to predict the long-term fate of polychlorinated biphenyls (PCBs) in San Francisco Bay and has been used for developing mass balances for polycyclic aromatic hydrocarbons, organochlorine pesticides, and polybrominated diphenyl ethers [7][8][9]. The current model of San Francisco Bay treats the bay as two well-mixed compartments representing the water column and surface sediments for the region.…”

Section: Regional Mass Balance Modelmentioning

confidence: 99%

A regional mass balance of methylmercury in San Francisco Bay, California, USA

Yee¹,

McKee²,

Oram³

2010

Enviro Toxic and Chemistry

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The San Francisco Bay (California, USA) is a water body listed as impaired because of Hg contamination in sport fish for human consumption, as well as possible effects on resident wildlife. A legacy of Hg mining in local watersheds and Hg used in Au mining in the Sierra Nevada (USA) has contributed to contamination seen in the bay, with additional more recent and ongoing inputs from various sources. Methylmercury is the species of Hg most directly responsible for contamination in biota, so better understanding of its sources, loads, and processes was sought to identify the best means to reduce impacts. A regional scale model of San Francisco Bay was developed to characterize major methylmercury inputs and processes. The model was used to evaluate the potential impact of uncertainties in estimates for methylmercury loading pathways and environmental processes, identify major data gaps, and explore management prospects for reducing methylmercury contamination. External loading pathways considered in the mass balance include methylmercury loads entering via atmospheric deposition to the bay surface, and discharges from the Sacramento/San Joaquin Delta, local watersheds, municipal wastewater, and fringing wetlands. Internal processes considered include exchange between bed and suspended sediments and the water column, in situ production and demethylation, biological uptake, and losses via hydrologic transport to the ocean through the Golden Gate. In situ sediment methylation and demethylation were dominant sources and losses determining ambient steady-state concentrations in the model, with changes in external loads and export causing smaller changes. Better information on methylation and demethylation is thus most critical to improving understanding of methylmercury balances and management.

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“…The use of this pesticide was banned in the majority of the world in the late 1980s, with use remaining high in areas such as California until 1988, when a ban was introduced in the US (Shigenaka, 1990;Connor et al, 2006). Chlordane is a mixture of different chlordane isomers, other chlorinated hydrocarbons and several other components.…”

Section: Introductionmentioning

confidence: 99%

Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere

et al. 2012

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Abstract. An extensive database of organochlorine (OC) pesticide concentrations measured at the Norwegian Arctic monitoring station at Ny-Ålesund, Svalbard, was analysed to assess longer-term trends in the Arctic atmosphere. Dynamic Harmonic Regression (DHR) is employed to investigate the seasonal and cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB), and to isolate underlying interannual trends. Although a simple comparison of annual mean concentrations (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) suggest a decline for all of the OCs investigated, the longer-term trends identified by DHR only show a significant decline for p, p -DDT. Indeed, HCB shows an increase from [2003][2004][2005]. This is thought to be due to changes in source types and the presence of impurities in current use pesticides, together with retreating sea ice affecting air-water exchange. Changes in source types were revealed by using isomeric ratios for the chlordanes and DDTs. Declining trends in ratios of trans-chlordane/cischlordane (TC/CC) indicate a shift from primary sources, to more "weathered" secondary sources, whereas an increasing trend in o, p -DDT/p, p -DDT ratios indicate a shift from use of technical DDT to dicofol. Continued monitoring of these OC pesticides is required to fully understand the influence of a changing climate on the behaviour and environmental cycling of these chemicals in the Arctic as well as possible impacts from "new" sources.

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

Cited by 41 publications

References 29 publications

Concentrations and loads of PCBs, dioxins, PAHs, PBDEs, OC pesticides and pyrethroids during storm and low flow conditions in a small urban semi-arid watershed

Concentrations and loads of PCBs, dioxins, PAHs, PBDEs, OC pesticides and pyrethroids during storm and low flow conditions in a small urban semi-arid watershed

A regional mass balance of methylmercury in San Francisco Bay, California, USA

Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere

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