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QSARs for aromatic hydrocarbons at several trophic levels
Author(s) -
Di Marzio Walter,
Saenz Maria Elena
Publication year - 2006
Publication title -
environmental toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 77
eISSN - 1522-7278
pISSN - 1520-4081
DOI - 10.1002/tox.20163
Subject(s) - bioconcentration , environmental chemistry , trophic level , daphnia magna , chemistry , partition coefficient , ethylbenzene , acute toxicity , invertebrate , ecotoxicology , benzene , toxicity , bioaccumulation , biology , ecology , chromatography , organic chemistry
Quantitative structure–activity relationships (QSARs) with aromatic hydrocarbons were obtained. Biological response was measured by acute toxicity of several aquatic trophic levels. The chemicals assayed were benzene, toluene, ethylbenzene, o ‐xylene, m ‐xylene, p ‐xylene, isopropylbenzene, n ‐propylbenzene, and butylbenzene. Acute toxicity tests were carried out with Scenedesmus quadricauda , as representative of primary producers; Daphnia spinulata , a zooplanctonic cladoceran; Hyalella curvispina, a benthic macroinvertebrate; and Bryconamericus iheringii, an omnivorous native fish. The EC 50 or LC 50 was calculated from analytical determinations of aromatic hydrocarbons. Nonlinear regression analysis between the logarithm of the octanol–water partition coefficient (log K ow ) of each compounds and the toxicity end points was performed. QSARs were positively related to increases in log K ow at all trophic levels. Intertaxonomic differences were found in comparisons of algae with animals and of invertebrates with vertebrates. We observed that these differences were not significant with a log K ow higher than 3 for all organisms. Aromatic hydrocarbons with log K ow values of less than 3 showed different toxicity responses, with algae more resistant than fish and invertebrates. We concluded that this was a result of the narcotic mode of action related to liposolubility and the ability of the compound to reach its target site in the cell. The bioconcentration factor (BCF) achieved to start nonpolar narcosis fell almost 1 order of magnitude below the BCF expected from the log K ow . Predicted critical body residues for nonpolar narcosis ranged between 2 and 1 mM. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 118–124, 2006.