Biological indicators of metal exposure in the brown trout (Salmo trutta Linnaeus, 1758) from the Krka River

Zahvaljujući sedrenim barijerama te brojnim slapištima i jezerima, rijeka Krka je 1985. godine proglašena nacionalnim parkom. U području grada Knina neadekvatno pročišćene komunalne i tehnološke otpadne vode bi mogle ugroziti živi svijet i fenomen sedrenih barijera, budući se ispuštaju samo 2 km uzvodno od granice parka. Njihov utjecaj procijenjen je na kakvoću vode i na ribe, potočnu pastrvu (Salmo trutta Linnaeus, 1758) na šest postaja uz grad Knin te izvoru rijeke Krke kao kontrolnoj postaji. Fizikalno-kemijski čimbenici ukazuju na pogoršanje kakvoće vode kod grada Knina. Koncentracije većine metala u vodi i staničnom citosolu jetre riba su povišene uz ispuste otpadnih voda u odnosu na izvor. Biomarkeri, rani biopokazatelji zagađenja (metalotioneini, ukupni citosolski proteini), ne potvrđuju značajne stanične promjene u riba iz toka kod grada Knina. Prikazani rezultati ukazuju na potencijalnu opasnost za očuvanje staništa u Nacionalnom parku Krka te je neophodno provoditi sustavni monitoring i praćenje kakvoće vode rijeke Krke. Thanks to the travertine barriers and many cascades and lakes, Krka River was proclaimed National Park in 1985. Near Town of Knin, municipal and industrial wastewaters may threaten living world and tufa barriers, since they are released without proper purification only 2 km upstream of the park border. Their influence on the water quality and on fish, brown trout (Salmo trutta Linnaeus, 1758) was evaluated on six locations near the Town of Knin and Krka source, as reference location. Physico-chemical water parameters pointed to deteriorated water quality at anthropogenically impacted locations. Levels of the most metals in the water and fish hepatic cytosol were increased near the wastewater outlets compared to the Krka source. Biomarkers, early warning signs of pollution (metallothioneins, total cytosolic proteins), did not confirm significant changes at the cellular level in fish from the watercourse near Knin. Presented results indicated potential threat to the habitat preservation in the Krka National Park. Therefore, implementation of water quality monitoring strategies of the Krka River is required.