Metabolites of 2-chlorosyringaldehyde in fish bile: indicator of exposure to bleached hardwood effluent

Abstract

1. 2-Chlorosyringaldehyde (2-CSA) is the major chlorinated phenol produced by the 100% chlorine dioxide bleaching of eucalypt pulp and is found in other bleached hardwood effluents. Almost nothing is known of the environmental or metabolic fates of this chemical. 2. Sand flathead (Platycephalus bassensis) was given 2-CSA by intraperitoneal injection at 0.15, 1.5, 15 and 75 mg/kg doses and, 4 days later, bile was collected and solvent extracted before and after enzymatic cleavage of conjugates. The acetate derivatives of bile extracts were analysed by gas chromatography/mass spectrometry. 3. The major metabolite 4 days after administration was the glucuronide or sulphate conjugate of 2-chloro-4-hydroxy-3,5-dimethoxy-benzylalcohol (2-CB-alcohol). The identity of 2-CB-alcohol was confirmed by chemical synthesis. 4. The quantity of 2-CB-alcohol in the bile was linearly related to dose of 2-CSA and was detected at all dose levels. Minor metabolites identified were conjugated 2-CSA, unchanged 2-CSA and 2-chloro-4-hydroxy-3,5-dimethoxy-benzoic acid. 5. The amount of 2-CB-alcohol in bile has the potential to be a sensitive and specific indicator of fish exposure or bleached hardwood effluent.

Short review of selected fish biomarkers of xenobiotic exposure with an example using fish hepatic mixed‐function oxidase

“…Conjugated derivatives of many xenobiotic compounds are known to be formed in vertebrate hepatocytes and transported into the bile (Klaasen & Watkins 1984). Thus the measurement of bile metabolites represents a chemical and species specific biomarker of xenobiotic exposure which can be an extremely sensitive indicator of water quality in some circumstances (Haritos et al, 1994).…”

The Effects of Exposure Duration and Feeding Status on Fish Bile Metabolites: Implications for Biomonitoring

“…The extraction and derivatization of chlorinated compounds in the bile were based on the method of Morales et al (1992), with modifications from Haritos et al (1995). Fractions were analyzed by gas chromatography/mass spectrometry (GC/MS) using a Shimadzu QP2000 (Japan).…”