Chemicals, including Pesticides, in Wastewater Discharge Contaminate Oysters in Pacific Northwest

July 8, 2021 | A Portland State University (PSU) study published in Marine Pollution Bulletin finds oysters of varying distances from wastewater discharge pipes along the Oregon and Washington state coast contain low levels of chemical contaminants. Although wastewater treatment facilities clean water draining from sinks and toilets, the process does not adequately remove all contaminants. The process can leave behind pharmaceutical drugs and personal care products (e.g., shampoos, cosmetics, deodorant) residues in treated water. PSU has already found that pesticides from the forestry industry threaten clams, mussels, oysters (bivalves) along the Oregon coast. Marine ecosystem pollution is difficult to track and measure, and pesticide regulations can invoke variations in water quality requirements through discrepancies in buffer zones and application concentrations. The combined presence of pesticides, medicine, and personal care products in aquatic environments has direct implications for species and ecosystem health and indirect consequences for human well-being. Springtime oyster samples, nearest wastewater sites, contain two pharmaceuticals: miconazole (a common antifungal medication) and virginiamycin (a common-use veterinary antibiotic medication). Additionally, researchers find four alkylphenols compounds (industrial chemicals used to make detergents, cleaner, and pesticide products) present in summertime oyster samples at both aquaculture and wastewater sites: 4-nonylphenol (NP), 4-tert-octylphenol (OP), and 4-nonyl- phenol mono- (NP1EO) and diethoxylates (NP2EO). [Ehrhart, Amy and Granek, Elise. Pharmaceuticals and alkylphenols in transplanted Pacific oysters (Crassostrea gigas): Spatial variation and growth effects. Marine Pollution Bulletin. 170:112584, 2021.]