Comment on “the long‐term fate of polychlorinated biphenyls in San Francisco bay, (USA)”

Connolly, John P.; Ziegler, C. Kirk; Lamoureux, Elizabeth M.; Benaman, Jennifer; Opdyke, Daniel R.

doi:10.1897/04-537.1

Cited by 6 publications

(11 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bay-specific model parameters were identical to those used in predicting the long-term fate of PCBs in the bay [6], with the addition of a tidal flushing ratio (a ¼ 3.75), a ratio of tidal exchange flow to net freshwater flow in the system. Tidal flushing was not included in the original mass balance model for PCBs but was added in response to review comments [30] and used in more recent applications of the model, such as the polybrominated diphenyl ethers mass balance [9]. Tidal flow rate determined the volume of bay water replaced with water from outside the Golden Gate (the seaward boundary) in each model time step.…”

Section: D)mentioning

confidence: 99%

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

Yee¹,

McKee²,

Oram³

2010

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

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.

show abstract

Section: D)mentioning

confidence: 99%

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

Yee¹,

McKee²,

Oram³

2010

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

show abstract

“…The comment of Connolly et al [1] contains a main point that is valuable and an important point that is inaccurate. Overall, discussion of the one‐box model of Davis [2] is moot because that model has served its purpose as the precursor of a more sophisticated and realistic multibox polychlorinated biphenyl (PCB) model for San Francisco Bay that is currently under development.…”

mentioning

confidence: 99%

“…The main point of Connolly et al [1] is a valid one that helps to advance the nascent science of modeling the long‐term fate of pollutants in San Francisco Bay. Tidal exchange is an important process that was not included in the one‐box model presented in Davis [2].…”

mentioning

confidence: 99%

“…An important error in the analysis of Connolly et al [1] was made in the interpretation of the mussel‐trend information presented in Davis [2]. Connolly et al [1] appropriately reference the mussel‐trend data as a crucial indicator of long‐term trends in PCB concentrations in the Bay. The trends actually measured in the mussels over the past 20 years are the best predictor available of what to expect in the next 20 years and beyond.…”

mentioning

confidence: 99%

“…The trends actually measured in the mussels over the past 20 years are the best predictor available of what to expect in the next 20 years and beyond. Unfortunately, Connolly et al [1] misinterpreted the trends indicated by the mussel data. Connolly et al [1] concluded from inspection of Figure 6 in Davis [2] that “PCB levels in the Bay have been declining at a rate of about 5 to 8% per year,” characterized later in the comment as a half‐life of eight years.…”

mentioning

confidence: 99%

See 2 more Smart Citations