Occurrence of contaminants of emerging concern in mussels (Mytilus spp.) along the California coast and the influence of land use, storm water discharge, and treated wastewater effluent

• Contaminants of emerging concern were measured in mussels along the California coast.
• Sixty-eight total stations. Sixty-seven of the 167 analytes had at least one detect.
• The influence of urbanization, agriculture, and ocean discharge was investigated.
• Alkylphenols, lomefloxacin, and PBDE were the most abundant contaminants.
• Perfluorinated compound and HBCD detection frequencies were greater than 25%.

Contaminants of emerging concern were measured in mussels collected along the California coast in 2009–2010. The seven classes were alkylphenols, pharmaceuticals and personal care products, polybrominated diphenyl ethers (PBDE), other flame retardants, current use pesticides, perfluorinated compounds (PFC), and single walled carbon nanotubes. At least one contaminant was detected at 67 of the 68 stations (98%), and 67 of the 167 analytes had at least one detect (40%). Alkylphenol, PBDE, and PFC concentrations increased with urbanization and proximity to storm water discharge; pesticides had higher concentrations at agricultural stations. These results suggest that certain compounds; for example, alkylphenols, lomefloxacin and PBDE, are appropriate for inclusion in future coastal bivalve monitoring efforts based on maximum concentrations >50 ng/g dry weight and detection frequencies >50%. Other compounds, for example PFC and hexabromocyclododecane (HBCD), may also be suggested for inclusion due to their >25% detection frequency and potential for biomagnification.