Leisure craft sacrificial anodes as a source of zinc and cadmium to saline waters

12 months embarg

BACKGROUND

Historically, agricultural activities have been the focus of investigations into pesticide impacts on water bodies. In recent years, however, pesticide use in urban areas is increasingly being examined as a potential source of aquatic pollutants. Although applications of pesticides in urban areas are typically on a small scale, the wide variety of chemicals used and the frequency of applications can result in a substantial amount of pesticides used. Urban-use pesticides can move off application sites and enter storm drains which route surface runoffs into urban creeks. These pesticides can also end up in urban sewage which then travels to wastewater treatment plants. Although conventional wastewater treatment techniques employed by Publicly Owned Treatment Works (POTWs) may remove certain pesticides with high efficiency, others may not be sufficiently removed. Thus, these pesticides can be present in the treated effluent and eventually be released into a receiving water body. Under the California Porter Cologne Act, the Regional Water Quality Control Boards (RWQCBs) regulate the quality of treated effluent by issuing wastewater discharge permits to POTWs. These permits prohibit toxic substances in the treated effluent at concentrations that may cause harm to aquatic species

CALIFORNIA ENVIRONMENTAL PROTECTION AGENCY

In the summer and fall of 2006, the Department of Pesticide Regulation (DPR) sampled water and sediment from 23 marinas to assess the geographical scope and severity of pollution stemming from the use of antifouling paint (AFP) pesticides in California. Copper, zinc, Irgarol, M1 (the primary breakdown product of Irgarol), and aquatic toxicity were selected as potential indicators of AFP pollution. The highest dissolved copper concentrations were observed in larger salt water marinas along California’s Central and South Coast, the lowest were seen in freshwater lake marinas. Copper and zinc concentrations were almost always higher in the marinas than in the adjacent local reference sites, indicating that significant sources of metals existed in the marinas. Concentrations of zinc never exceeded California’s water quality standards. In contrast, concentrations of dissolved copper in salt and brackish water marinas were frequently above California water quality standards established for the protection of aquatic life. Developmental toxicity tests on the copper-sensitive embryo of the mussel Mytilus galloprovincialis were conducted on 47 marina water samples. Eight of these samples showed a statistically significant toxic response and copper was the likely cause of the toxicity. Several copper toxicity models that account for copper bioavailability to aquatic organisms were used to predict toxicity for the 517 samples for which sitespecifi