M4 AM Endocrine Disruption in Fish
Monday, 14 November 2005: 8:00 AM - 11:40 AM in Ballroom 4

(SCH-1117-731514) In vivo Bioassay Guided Fractionation of Marine Sediment Extracts from the Southern California Bight for Estrogenic Activity.

Schlenk, D¹, Sapozhnikova, Y.¹, Irwin, M.¹, Reddy, S.², Brownawell, B², Kolodziej, E.³, Sedlak, D.³, Montagne, D.⁴, Armstrong, J.⁵, Snyder, S.⁶, ¹ University of California, Riverside, Riverside, CA, USA² Stonybrook University, Stonybrook, NY, USA³ University of California, Berkeley, Berkeley, CA, USA⁴ Los Angeles County Sanitation District, Whittier, CA, USA⁵ Orange County Sanitation District, Fountain Valley, CA, USA⁶ Southern Nevada Water Authority, Las Vegas, NV, USA

ABSTRACT- The exposure and uptake of environmental estrogenic compounds have been reported in previous studies of demersal flatfish species in the central Southern California Bight (SCB). The objective of this study was to evaluate the feminizing activity of marine sediments from the SCB by using in vivo vitellogenin (Vtg) assays in male or juvenile fish. In 2003, sediments were collected near wastewater outfalls serving the counties of Los Angeles (LACSD) and Orange (OCSD), and the city of San Diego (SD). Cultured male California Halibut (CH) (Paralichthys californicus) were either directly exposed to sediments for 7 days or treated with two intraperitoneal injections of sediment extract over seven days. 17B-Estradiol (E2) equivalent values ranged from 1-90 ug/kg with LACSD > SD > OCSD. Measurable concentrations of E2 were observed in all sediment extracts and ranged from 0.16 to 0.45 ng/g. Estrone (E1) was only observed in sediments near the LACSD outfall (0.6 ng/g). Alkylphenols and alkylphenol ethoxylates were observed in all sediment samples but were highest near the OCSD outfall where concentrations of nonylphenol were 3200 ng/g. Fractionation studies of the LACSD sediment extract failed to demonstrate relationships between Vtg expression and 62 analytes including E2, which was observed in whole extract (2.9 ng/g). Oxybenzone (1.6 ng/g) was identified in bioactive fractions as well as unknown compounds of relatively high polarity. These results indicate estrogenic compounds other than classic natural and xenoestrogens may contribute to estrogenic activity of sediments from the SCB.

Key words: oxybenzone, estrogen, sediment, vitellogenin