Accumulation of mutagenic activity in bile fluid of river Rhine fish

Considerable mutagenic activity can be detected in the bile of natural fish (bream Abramis brama) from the river Rhine. Like the river water, organic mutagens can be extracted from aqueous bile by adsorption on XAD-resins. The mutagenic activity of the fish bile in the Amestest resembles that of the river water with regard to strain specificity (TA 98 and TA 1538) and the effect of S-9 (enhancement). However, relative to the river water, the activity in the bile is at least 10(4)-fold higher. No mutagenic activity can be detected in the bile of bream from the river Meuse, which contains little activity in the water itself. Seasonal changes in the level of Rhine water mutagenicity roughly coincide with similar changes in the activity of bile from Rhine fish. Finally, additional mutagenic activity can be observed in the bile of Rhine fish after treatment with beta-glucuronidase.