Bioindicator field monitoring: Use of fish biochemical parameters at a modern bleached kraft pulp mill site

Abstract

Integrated studies of community, population, individual, and suborganismal level effects in aquatic ecosystems have been rare. We have initiated such a program at the P & G Cellulose mill in Alberta: some preliminary biomarker results are presented here. Mountain whitefish (MTWT) from immediately below the plant, 120 km downstream, and a spawning site 65 km upstream showed ranges of organochlorines from non-detectable to elevated concentrations. Although some fish exposed to organochlorines showed P4501A induction, others with similar body burdens did not. Differential denaturation of hepatic P450 to P420 occurred in both MTWT and longnose suckers (LNSK), which presumably also caused differential inactivation of ethoxyresorufin O-deethylase activity. Thus, immunoblotting was employed to determine P4501A specific content. LNSK, which showed lower levels of organochlorines, exhibited modest P4501A increases. These results emphasize the migratory nature of MTWT and indicate that caution is required in interpreting chemical or biomarker data in isolation: chemical burdens did not always correlate with P4501A induction.