title: Site-specific profiles of estrogenic activity in agricultural areas of California's inland waters.
abstract: To evaluate the occurrence and sources of compounds capable of feminizing fish in agriculturally impacted waterways of the Central Valley of California, water samples were extracted and subjected to chemical analyses as well as in vitro and in vivo measurements of vitellogenin in juvenile rainbow trout (Oncorhynchus mykiss). Among the 16 sites sampled, 6 locations frequently exhibited elevated concentrations of estrogenic substances with 17beta-estradiol equivalents up to 242 ng/L in vitro and 12 microg/kg in vivo. The patterns of activity varied among sites, with two sites showing elevated activity only in vitro, two showing elevated activity only in vivo, and two showing elevated activity in both assays. Sequential elution of solid-phase extraction (SPE) disks followed by bioassay-guided fractionation was used to characterize water samples from the two locations where activity was observed in both bioassays. The highest estrogenic activity was observed in the most nonpolar fractions (80-100% methanol eluent) from the Napa River, while most of the activity in the Sacramento River Delta eluted in the 60% methanol eluent. Quantitative analyses of SPE extracts and additional HPLC fractionation of the SPE extracts by GC-MS/MS and LC-MS/MS indicated concentrations of steroid hormones, alkylphenol polyethoxylates, and herbicides that were at least 1-3 orders of magnitude below bioassay 17beta-estradiol equivalent calculations. Given the different patterns of activity and chemical properties of the estrogenic compounds, it appears that estrogenic activity in these agriculturally impacted surface waters is attributable to multiple compounds. Further investigation is needed to identify the compounds causing the estrogenic activity and to determine the potential impacts of these compounds on feral fish.
authors.affiliation: Department of Environmental Sciences, University of California, Riverside, California 92521, USA.
authors.forename: Ramon
authors.initials: R
authors.lastname: Lavado
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Loyo-Rosales
authors.forename: Emily
authors.initials: E
authors.lastname: Floyd
authors.forename: Edward P
authors.initials: EP
authors.lastname: Kolodziej
authors.forename: Shane A
authors.initials: SA
authors.lastname: Snyder
authors.forename: David L
authors.initials: DL
authors.lastname: Sedlak
authors.forename: Daniel
authors.initials: D
authors.lastname: Schlenk
mesh_terms: D000383:Agriculture; D000818:Animals; D002140:California; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring / Q000379:methods; D004967:Estrogens / Q000032:analysis*; D005618:Fresh Water / Q000737:chemistry*; D017686:Oncorhynchus mykiss; D045483:Rivers / Q000737:chemistry; D012623:Seawater / Q000737:chemistry*; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004967:Estrogens; D014874:Water Pollutants, Chemical