3,5-Dimethoxybenzylalcohol

The effects of exposure duration and feeding status on fish bile metabolites: implications for biomonitoring.[Pubmed:9515087]

Ecotoxicol Environ Saf. 1998 Feb;39(2):147-53.

Biliary metabolites of 2-chlorosyringaldehyde (2-CSA), the major chlorinated phenol found in chlorine dioxide bleached eucalypt pulp effluent, have been found to be sensitive biomarkers of effluent exposure in the sand flathead (Platycephalus bassensis). Before this method of biomonitoring can be applied in the field, the influences of exposure duration, depuration time, and fish feeding status on the level of this metabolite should be determined. In this study, sand flathead were exposed to a measured concentration of 0.3 microgram/1 of 2-CSA for 1, 2, 4, 8, 12, or 16 days. Fish previously exposed to 2-CSA were then held in sea-water alone for 1, 2, 3, 4, or 6 days. Fish were fed ad libitum throughout the experiment, and the fullness of the fish's stomach at the time of sampling was noted. There were no effects of exposure on biotransformation enzyme activities, either between exposure times or between the exposure and depuration periods. The major metabolite of 2-CSA, 2-chloro-4-hydroxy-3,5-Dimethoxybenzylalcohol (2-CB-OH), was first detected in the bile of some fish sampled after 24 h of exposure, and the mean concentration of 2-CB-OH in the bile increased over the exposure period. The mean concentration (+/- SE) of 2-CB-OH in the bile was strongly influenced by fish feeding status, being 94 +/- 18 ng/ml bile in fish with empty stomachs and undetectable in fish with full stomachs. Bile volume was also influenced by fish feeding status, being greatest in fish with empty stomachs at the time of sampling. Results indicate that the feeding status of fish should be taken into consideration when using biliary metabolites as biomarkers of effluent exposure in the field, and methods to establish this are discussed.

Metabolites of chlorinated syringaldehydes in fish bile as biomarkers of exposure to bleached eucalypt pulp effluents.[Pubmed:8727518]

Ecotoxicol Environ Saf. 1996 Apr;33(3):253-60.

Metabolites of chlorinated phenolic compounds in fish bile have been found to be sensitive biomarkers of bleached pulp mill effluent exposure. Chlorinated syringaldehydes are largely unstudied chlorophenolics found in bleached hardwood effluent. Sand flathead (Platycephalus bassensis), Australian marine fish, were exposed to 100% chlorine dioxide-bleached eucalypt pulp effluent at concentrations of 0.5, 2, and 8% (v/v) for 4 days. Metabolites of 2-chlorosyringaldehyde (2-CSA), the predominant chlorophenolic in this effluent, were measured in the bile. The major metabolite was the conjugate of 2-chloro-4-hydroxy-3,5-dimethoxy-benzylalcohol (2-CB-OH), the reduced product of 2-CSA. 2-CB-OH was found in all fish exposed to diluted effluent and was concentrated in the bile over 1000 times above 2-CSA levels in the effluent. A separate experiment examined the metabolic fate of 2,6-dichlorosyringaldehyde (2,6-DCSA), which is one of the major chlorophenolics in chlorine-bleached eucalypt pulp effluent. Sand flathead were exposed to 2,6-DCSA by intraperitoneal injection at 15 mg/kg or through the water to 0.5, 2, or 8 micrograms/liter for 4 days. Analysis of the bile revealed the major metabolite of 2,6-DCSA to be the conjugate of 2,6-dichloro-4-hydroxy-3,5-Dimethoxybenzylalcohol, which was found in all exposed fish and was concentrated in the bile over 20,000 times above 2,6-DCSA exposure levels. Results reveal that the analysis of metabolites of chlorinated syringaldehydes in fish bile can provide a biomarker of bleached hardwood effluent exposure that is sensitive to low levels of exposure, specific to certain bleaching sequences, and correlates well with exposure concentrations.