Induction of cytochrome P-450 activity in individual Chironomus riparius Meigen larvae exposed to xenobiotics

Cytochrome P450 activity in individual Chironomus riparius larvae was measured using a microtiter plate adaptation of the ethoxyresorufin-O-deethylase (EROD) assay. The sensitivity of this biomarker was tested by exposing larvae to phenobarbital (0.5 and 1.0 mM) and permethrin (1 and 10 mug/g). Both chemicals induced EROD activity in C. riparius larvae by up to 1.58-fold with PB and 2.47-fold with permethrin. EROD induction was more pronounced after 48 h. The initially high EROD activity in the controls suggested that P450s are induced by stress. Feeding levels prior to exposure also had a significant effect on EROD activity. EROD activity compared to the control was highest when larvae were fed double the normal ration. These results indicate that EROD activity in individual C. riparius may be a useful biomarker to add to a suite of biomarkers for the detection of freshwater pollution. (C) 2002 Elsevier Science (USA). All rights reserved.

Effects of dredging in Goteborg Harbor, Sweden, assessed by biomarkers in eelpout (Zoarces viviparus)

We used a battery of biomarkers in fish to study the effects of the extensive dredging in Goteborg harbor situated at the river Gota alv estuary, Sweden. Eelpout (Zoarces viviparus) were sampled along a gradient into Goteborg harbor, both before and during the dredging. Biomarker responses in the eelpout before the dredging already indicated that fish in Goteborg harbor are chronically affected by pollutants under normal conditions compared to those in a reference area. However, the results during the dredging activities clearly show that fish were even more affected by remobilized pollutants. Elevated ethoxyresorufin-O-deethylase activities and cytochrome P4501A levels indicated exposure to polycyclic aromatic hydrocarbons. Elevated metallothionein gene expression indicated an increase in metal exposure. An increase in general cell toxicity, measured as a decrease in lysosomal membrane stability, as well as effects on the immune system also could be observed in eelpout sampled during the dredging. The results also suggest that dredging activities in the Gota alv estuary can affect larger parts of the Swedish western coast than originally anticipated. The present study demonstrates that the application of a set of biomarkers is a useful approach in monitoring the impact of anthropogenic activities on aquatic environments.