Nonylphenols in sediments and effluents associated with diverse wastewater outfalls

Nonylphenols (NPs) have been reported to disrupt endocrine function and sexual development in aquatic organisms at low concentrations. Environmental NP burdens are predominantly derived from degradation of nonylphenol polyethoxylate surfactants. We detected NPs in discharge-associated riverine sediments adjacent to 11 of 20 active sewage treatment plants (STPs) at concentrations up to 12,400 μg/kg. While most previous studies have focused on STPs, nonylphenols were observed in association with a variety of outfall types. The highest sediment burden, 14,100 μg/kg, was detected near a federal facility's stormwater discharge. Of 75 sediments examined from 67 sites, 45% contained NP concentrations >5 μg/kg; median concentration in these NP-positive sediments was 369 μg/kg. Other surfactant-derived alkylphenolic compounds, specifically 4-tert-octylphenol and 4-cumylphenol, were observed in two sediments at 8,220 and 70,000 μg/kg, respectively. The maximum NP concentration detected in an effluent, 6,300 μg/L, was from a shipyard oil/water separator. Nonylphenols were detected (> 1.0 μg/L) in 20% of the 59 effluents examined; 10% exceeded 10 μg/L. Sediments sampled near a STP that had ceased treatment operations 20 years prior contained 54,000 μg/kg, indicative of long-term NP residence. Results indicate that NPs may be released from diverse sources, concentrate in associated sediments, and persist therein for extended periods.