title: Changes in toxicity and dioxin-like activity of sediments from the Tietê River (São Paulo, Brazil).
abstract: Acute cytotoxicity (neutral red assay), AhR-mediated toxicity (CYP P450 1A induction potential-EROD assay) and concentrations of PAHs were recorded in RTL-W1 cells to assess the ecotoxicological potential of sediments from reservoirs along the Tietê River and the Pinheiros River (Brazil). Almost all sediments tested induced cytotoxicity and stimulated cytochrome P450-associated EROD activity. Toxicity increases from Tietê River spring to São Paulo city region and decreases towards downstream. A closer analysis of chemical measurements of PAHs and results from bioassay revealed that the PAHs analyzed could not explain more than 7% of the EROD-inducing potencies. Results confirm that most of the toxicity is due to the discharges of the metropolitan area of São Paulo. Moreover, they indicate additional sources of pollutants along the river course, which contribute to the degradation of each reservoir.
authors.affiliation: Aquatic Ecology and Toxicology Section, Institute for Zoology, University of Heidelberg, Im Neuenheimer Feld 230, D-69120 Heidelberg, Germany. rocha@zoo.uni-heidelberg.de
authors.forename: Paula
authors.initials: P
authors.lastname: Suares Rocha
authors.forename: Ehab
authors.initials: E
authors.lastname: Azab
authors.forename: Burkhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Volker
authors.initials: V
authors.lastname: Storch
authors.forename: Henner
authors.initials: H
authors.lastname: Hollert
authors.forename: Thomas
authors.initials: T
authors.lastname: Braunbeck
mesh_terms: D000818:Animals; D001938:Brazil; D002460:Cell Line; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis; D004147:Dioxins / Q000032:analysis / Q000633:toxicity*; D054750:Ecotoxicology; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity*; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D004147:Dioxins; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D019363:Cytochrome P-450 CYP1A1