Sources and Fate of Contaminants of Emerging Concern in Southern California Coastal Areas.

Occurrence, fate and biological effects of contaminants of emerging concern (CECs) were investigated in municipal effluents, offshore seawater and marine flatfish.   Analyzed samples included final effluent from four large Publicly Owned Treatment Works (POTWs), bottom seawater collected near the respective POTW outfall discharges, and a reference site in Southern California (USA).  We investigated biological effects and CEC accumulation in hornyhead turbot (Pleuronichthys verticalis).  Plasma concentrations of vitellogenin and hormones were measured to assess endocrine responses.  Gonads were analyzed to investigate feminization of male fish and reproductive condition.  Naproxen, gemfibrozil, and atenolol, were consistently detected in effluents at concentrations greater than one µg/L, concentrations of other target CECs were low.  CEC concentrations primary treated effluent tended to be higher than those in effluents that received secondary treatment.  Despite the high level of dilution, several CECs were found in seawater: naproxen, atenolol, and gemfibrozil exhibited the highest concentrations.  Triclosan and nonylphenol were commonly detected in sediments.  Diazepam, nonylphenol and PBDEs were bioaccumulated by the fish.  The results indicate that municipal wastewater discharges are a source of CECs exposure to fish in offshore waters.  We found apparent alterations in several hormone systems, but these alterations showed inconsistent relationships to current POTW discharges.   Hornyhead turbot reproductive condition and population size did not appear to be impacted in the discharge areas.   While biological responses in individuals that could be attributed to CECs exposure were observed, the cause is still uncertain.  Additional studies are underway to determine how significant the presence of CECs is in marine systems.