HISTOCHEMICAL AND BIOCHEMICAL MARKERS IN TROUT LARVAE EXPOSED TO RIVER SEDIMENTS

Rainbow trout larvae (Oncorhynchus mykiss) were exposed to bottom sedi ments collected from 4 sites of the River Po, located close to the spr ings (UP) of the main Italian river and downstream the confluence of 3 tributaries of its middle reach, the Rivers Ticino (TI), Adda (AD) an d Lambro (LA), which drain areas characterized by increasing anthropog enic stress. After 7 days of exposure the trout larvae were examined f or both biochemical and histochemical markers and results indicate the presence of a toxicological risk for the fish community of the AD- an d particularly LA-downstream stretches. The reach of the River Po rece iving the Ticino River was confirmed to be less hazardous in conjuncti on with the UP area. (C) 1998 Elsevier Science Ltd. All rights reserve d.