title: Influence of humic acid on bioavailability and toxicity of benzo[k]fluoranthene to Japanese medaka.
abstract: Japanese medakas (Oryzias latipes) and triolein-embedded cellulose acetate membranes (TECAMs) were exposed simultaneously to benzo[k]fluoranthene (BkF) in the static exposure system containing different concentrations of humic acid (HA). The concentration-response relationships of induced hepatic 7-ethoxysorufin-o-deethylase (EROD) activity were established in regard to the nominal water concentration of BkF and the free concentration estimated using TECAM, as well as the body residues, respectively. In general, bioaccumulation of BkF and EROD activity in medaka were reduced with an increase of HA concentration in the exposure medium. The concentration-response relationships varied with HA concentration when expressed in nominal concentration. However, these relationships overlapped completely and partially when expressed in body BkF residue and in free BkF concentration estimated by TECAM, respectively. HA treatments were slightly beyond the 0.95 confidence band of HA-free control thereby indicating the participation of BkF-HA complex to the bioavailability and toxicity. On the basis of the bioavailability model, it was estimated that approximately 17-22% and 13-18% of BkF-HA complex contributed to the bioaccumulation and/or to the induced toxic effect, correspondingly.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Chen
authors.forename: Runhui
authors.initials: R
authors.lastname: Ke
authors.forename: Jinmiao
authors.initials: J
authors.lastname: Zha
authors.forename: Zijian
authors.initials: Z
authors.lastname: Wang
authors.forename: Shahamat U
authors.initials: SU
authors.lastname: Khan
mesh_terms: D000818:Animals; D001682:Biological Availability; D002482:Cellulose / Q000031:analogs & derivatives / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005449:Fluorenes / Q000493:pharmacokinetics* / Q000633:toxicity*; D006812:Humic Substances; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008567:Membranes, Artificial; D009990:Oryzias / Q000378:metabolism*; D012044:Regression Analysis; D018675:Toxicity Tests; D014304:Triolein / Q000378:metabolism
chemical_list: D005449:Fluorenes; D006812:Humic Substances; D008567:Membranes, Artificial; D014304:Triolein; C005062:acetylcellulose; D002482:Cellulose; C022921:benzo(k)fluoranthene