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Toxic potencies of extracts of sediment and settling particulate matter collected in the recipient of a bleached pulp mill effluent before and after abandoning chlorine bleaching
Author(s) -
Engwall Magnus,
Broman Dag,
Dencker Lennart,
Näf Carina,
Zebühr Yngve,
Brunström Björn
Publication year - 1997
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620160613
Subject(s) - bioassay , pulp mill , effluent , chemistry , environmental chemistry , potency , paper mill , particulates , chlorine , pulp (tooth) , sediment , chromatography , in vitro , biology , biochemistry , environmental science , organic chemistry , environmental engineering , ecology , medicine , paleontology , pathology
Abstract Extracts of bottom sediment and settling particulate matter (SPM) samples collected in the recipient water body of a bleached pulp mill effluent were separated into three fractions: monoaromatic/aliphatic compounds, diaromatic compounds (e.g., polychlorinated biphenyls, polychlorinated dibenzo‐ p ‐dioxins, and polychlorinated dibenzofurans), and polyaromatic compounds (e.g., polycyclic aromatic hydrocarbons [PAHs]). The fractions were then tested for dioxinlike potency. The methods used for the assessment of dioxinlike potency were an in vitro assay, based on the induction of 7‐ethoxyresorufin‐ O ‐deethylase (EROD) in chicken embryo livers, a test for EROD induction in ovo using chicken embryos, and an immunotoxicity test measuring inhibition of lymphoid cell development in cultured fetal mouse thymuses. The samples collected closest to the mill were the most potent. There was a time‐dependent decrease in dioxinlike potency in the SPM samples collected near the mill, which coincided with the cessation of chlorine gas bleaching at the mill. The bioassays in general, and the in vitro chicken embryo liver bioassay in particular, proved useful in the assessment of dioxinlike compounds in the sediment and SPM samples. The polyaromatic fractions of the samples were generally more potent than the diaromatic fractions. Only a small part of the effects caused by the polyaromatic fractions could be explained by 15 analyzed PAHs, indicating the presence of unquantified polyaromatic compounds with dioxinlike effects. This investigation indicates that the cessation of chlorine bleaching in the pulp mill resulted in a reduced load of diaromatic dioxinlike compounds in the recipient water body.