PROJECT GRADE WAS "A" for the first two project periods.

FINAL PROJECT GRADE: A.

The aim of this project is to extend the knowledge on the consequences of metal pollution in the freshwater ecosystems using two freshwater bioindicators, fish species northern pike (Esox lucius) and the bivalves from the family Unionidae, from the ecologically important Croatian river Mrežnica, which, in its lower course, is impacted by the waste of several industrial facilities. The information on the river water and sediment contamination with metals will be associated with the information on the metal bioaccumulation and responses of several biomarkers(of general stress, metal exposure, antioxidative capacity and oxidative damage) in the fish liver and bivalve digestive gland, as their main metabolic and detoxification organs, as well as with the information on the fish health status. The project also aims to clarify the fate of metals in fish and bivalve tissues and cells, by application of metallomic approach. By use of three HPLC techniques (size exclusion, anion and cation exchange) combined with HR ICP-MS, metal distribution among cytosolic biomolecules of different sizes and charges in the northern pike liver and bivalve digestive gland will be determined. The metal-binding biomolecules of interest, which could be used as biomarkers of metal exposure or effects, will be further characterized and identified by two mass spectrometry methods (MALDI-TOF-MS and LC-MS/MS). The obtained information will lead to increased understanding of metal functions, detoxification and mechanisms of metal toxicity. Another important aspect of the project will be the assessment of the ecological status of the Mrežnica River and the recognition of the most threatened locations and the most important contaminants, which will help liable authorities to ensure the most effective protection of the water quality and the preservation of the aquatic life of this river.