Ispitivanje sadržaja teških metala i metaloida u tkivima rečne ribe kao pokazatelja bezbednosti mesa ribe i zagađenja životne sredine : doktorska disertacija / Testing of heavy metals and metalloids in tissues of river fish as indicators of fish meat safe

The aim of examination within this doctoral dissertation is determination of the content of heavy metals and metaliods (Hg, Cd, Pb, As, Fe, Zn, Ni, Cu) in the sediment and water of river Danube (at two profiles, profile A Batajnica,Belegiš, profile BVinča, Grocka) as well as mascular tissue and organs of fish (Pb, Cd, Hg, As) which can serve as an indicator of safety of fish as food but also as an indicator of environmental pollution. For the purpose of examination, ten samples of water and ten samples of sediment from the profile A and profile B was sampled (40 samples). Samples of fish (silver carp, carp, catfish) were taken from local professional fisherman. 15 samples of fish was taken from each type of fish at profile A and profile B (90 fish in total). For the examination of the content of heavy metals and arsenic, from each fish, a sample of muscular tissue, liver and digestive tract was taken (in total 270 samples). For the examination, atomic absorption spectrophotometer was used. At the examined profiles, the content of lead, mercury and nickel in Danube water was under the treshold of sensitivity of applied examination methods. The average content of zinc, arsenic and copper in water samples at the examined profiles was under, and content of iron above prescribed values for the quality of water of the second class. The average content of arsenic and heavy metals (Pb, Cd, Hg, Zn, Fe, Ni and Cu) in samples of sediment of Danube taken at profile B (downstream of Belgrade) was statistically significantly bigger than the average content of these elements in the samples of sediment taken at profile A (upstream from Belgrade). In muscular tissue and liver of silver carp caught at profile B the content of Pb, Cd, Hg and As was statistically significantly bigger than the content of these elements in muscular tissue and liver of silver carp caught at profile A. Between average contentof examined elements in digestive tract of silver carp caught at profiles A and B statistically significant difference was not determined. W carp caught at profile B) statistically significant differences between average content of arsenic and heavy metals in muscular tissue, digestive tract and liver of carp caught at profiles A and B were not determined. In all cases of comparison, except between the average content of arsenic in muscular tissue of catfish at profile A and B, the average content of arsenic and heavy metals was statistically significantly bigger in muscular tissue, content of digestive tract and liver of the one caught at profile A. With an exception of average content of cadmium in muscular tissue of silver carp, carp and catfish caught at profile B in all other cases of comparison statistically significant difference between average content of arsenic and heavy metals in muscular tissue of examined types of fish at both profiles was determined.The biggest average values of lead and mercury were determined at catfish, arsenic at silver carp and cadmium at carp. Average content of mercury in muscular tissue of catfish at profile B was above the prescribed values. Between average content of arsenic and heavy metals in digestive tract of examined types of fish at both examined profiles, statistically significant differences were determined.The biggest average content of lead is determined at bighead carp, cadmium and mercury at catfish and arsenic at bighead carp.Between average content of arsenic and heavy metals in liver, with an exception of mercury at profile B of examined types of fish, statistically significant differences were determined. The biggest average content of lead, cadmium and arsenic was determined in liver of bighead carp and mercury in liver of catfish. Ratios of average contents of arsenic and heavy metals in muscular tissue, content of digestive tract and liver of examined types of fish indicate that the average content of lead was the biggest in digestive tract and liver of silver carp and muscular tissue of catfish, cadmium in digestive tract of catfish and liver and muscular tissue of silver carp, mercury in digestive tract and liver of silver carp and muscular tissue of catfish and arsenic in digestive tract of catfish, liver of silver carp and muscular tissue of carp. From the obtained data it is seen that the place of cathing the fish has a significant influence to the content of arsenic and heavy metals in muscular tissue, digestive tract and liver of fish. Data on findings of heavy metals at fish as well as content of arsenic and heavy metals in water and sediment, at the same time, speak about safety of fish as food and may be an indicator of environmental pollution.