Prostorni monitoring teških metala kopnenih voda Srbije na osnovu bioakumulacije u ribama

Abstract

Rezime: Akvatični ekosistemi se nalaze pod najintenzivnijim antropogenim uticajem koji je doveo do povećanog prisustva zagađujućih materija, pa i velikog broja toksičnih zagađivača, prvenstveno teških metala, što zahteva permanentni monitoring. Bioakumulacijski monitoring (biomonitoring) je neophodan dodatak hemijskim analizama usled mogućnosti integracije uticaja na različite taksonomske grupe tokom dužeg vremenskog perioda, tako da je bolji pokazatelj promena u akvatičnoj sredini. Ribe predstavljaju jedan od najindikativnijih faktora za procenu zagađenja voda teškim metalima, a to je važno ne samo u procesu zaštite životne sredine, već i u proceni kvaliteta mesa i potencijalnog rizika za ljudsku populaciju. Ciljevi ovog istraživanja bili su: analiza nivoa akumulacije teških metala u mišićnom tkivu ispitivanih vrsta riba, poređenje akumuliranih teških metala u mišićnom tkivu između različitih vrsta riba, veza između koncentracija teških metala akumuliranih u mišićnom tkivu ispitivanih vrsta i koncentracija teških metala u vodi, izbor potencijalno osetljive riblje vrste za monitoring studije teških metala, mogućnost primene indeksa zagađenja teškim metalima (engl. Metal Pollution Index - MPI) u proceni zagađenja voda teškim metalima, formiranje preliminarne mape zagađenja voda teškim metalima u Srbiji i poređenje koncentracija akumuliranih teških metala u mišićnom tkivu ispitivanih riba sa maksimalno dozvoljenim koncentracijama (MDK) propisanih zakonskim regulativama EU i Republike Srbije. Najvažnije komercijalne vrste riba smuđ, som, deverika, mrena, skobalj i klen su proučavane u rekama, dok su u akumulacijama proučavane smuđ, som, deverika i babuška. Takođe, mogućnost upotrebe uklije kao bioindikatora kontaminacije voda teškim metalima je takođe ispitana.

Summary: Aquatic ecosystems are under extremely intense anthropogenic pressure that has led to an increased presence of pollutants, primarily a large number of toxic pollutants, especially heavy metals, which requires permanent monitoring. Bioaccumulation monitoring (biomonitoring) is a necessary addition to chemical analysis because it can be used to integrate impacts on different taxonomic groups over an extended period of time, so it is a better indicator of changes in the aquatic environment. Fish are one of the most indicative factors for the assessment of heavy metal water pollution, and they are important not only in the process of environmental protection, but also in assessing the quality of meat and the potential risk to the human population. The objectives of this research were: to analyze the level of accumulation of heavy metals in the muscle tissue of the fish species examined; to compare the accumulated heavy metals in the muscle tissue of different fish species; to make a connection between the concentration of heavy metals in the muscle tissue of the fish species examined and the concentrations of heavy metals in the water, to select potentially sensitive fish species for monitoring the study of heavy metals, to investigate the possibility of applying the index of heavy metal pollution (Metal Pollution Index - MPI) to the assessment of heavy metal water pollution; to make a preliminary map of heavy metal water pollution in Serbia; and to compare the accumulated concentration of heavy metals in fish muscle tissue with the maximum permissible concentrations (MPC) established by EU and national legislation. The most important commercial fish species, catfish, bream, barbel, nase and chub, were studied in rivers, while perch, catfish, bream and Prusian carp were studied in reservoirs. Bleak were also studied as bioindicators of water contaminated with heavy metals. The analysis of metals and metaloids Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn was performed with an ICP-OES Thermo Scientific iCAP 6500 Duo ICP (Thermo Fisher Scientific, Cambridge, United Kingdom) spectrometer. This study indicated a good response of fish to environmental changes, making them suitable bioindicators of heavy metal pollution in aquatic ecosystems. The benthophagous species bream and barbel, which feed near the bottom, were identified as sensitive bioindicators of heavy metal water pollution in aquatic ecosystems. The predatory fish species catfish and omnivorous fish species Prusian carp were also shown to have important bioindicator potential. It was also shown that the MPI is a reliable index for expressing the status of heavy metal pollution in muscle tissue, presenting a clear picture of heavy metal pollution in aquatic ecosystems. With that in mind, the MPI index can be potentially included in complex programs of monitoring of heavy metals in freshwater ecosystems in Serbia. With the use of MPI values, a classification of heavy metal water pollution in the major rivers and reservoirs in Serbia was proposed, showing the spatial patterns of heavy metals. This led to the identification of sites unaffected by direct pollution with heavy metals, slightly affected and affected. As a result of this water quality classification, a map of heavy metal water pollution in Serbia was formed. According to this classification, the Tisa River can be categorized as a site unaffected by direct pollution with heavy metals, while the West Morava and Pek can be categorized as affected. Other rivers are slightly affected. The Gruţa, Bovan and Aleksandrovac accumulations can be classified as slightly affected ecosystems. The As, Fe, Cu, and Zn concentrations detected in all of the fish muscle were below the MPC established by both the EU and the Republic of Serbia. The concentrations of Hg, Cd and Pb were above the MPC at several locations. Pb stands out with concentrations above the MPC in chub, barbel and nase meat at most sites. Cd concentrations were above the MPC in bream meat from the Aleksandrovac accumulation. The Pb concentrations were above the MPC in bream meat from the Bovan and Aleksandrovac accumulations, while the Fe concentrations were above the MPC in perch meat from the Bovan accumulation. In the bleak meat, metal concentrations were not above the MPC.