SANITARY AND ENVIRONMENTAL SAFETY ASSESSMENT OF FISH FROM RESERVOIRS OF THE NORTHERN AND CENTRAL KAZAKHSTAN

The article presents the results of research on the degree of fish contamination with heavy metal salts (Cd, Pb, Hg, As) and radionuclides (cesium-137, strontium-90) in selected water bodies of the Northern and Central Kazakhstan (Akmola and Karaganda regions). It was found that in the Akmola region, lead and arsenic were present in fish from all the studied reservoirs, cadmium and mercury only in fish from four reservoirs (40% of cases). The greatest accumulation of cadmium up to 0.085±0.0001 mg/kg was observed in fish from Lake Aidabul (Zerendy district), mercury up to 0.22±0.001 mg/kg from Lake Balyktykol (Shortandy district), lead up to 0.075±0.0018 mg/kg from Lake Baratay (Zerendy district), and arsenic up to 0.043±0.002 mg/kg from Lake Aidabul (Zerendy district). In fish from reservoirs of the Karaganda region, the content of lead, arsenic and cadmium was noted in all the samples studied, mercury was not detected in only two reservoirs. Cadmium content in the highest concentration up to 0.113±0.001 mg/kg was found in fish from Lake Bata, lead up to 0.081±0.0012 mg/kg in fish from the Irtysh-Karaganda canal, arsenic up to 0.0488±0.0012 mg/kg in fish from the Intumak reservoir (all reservoirs from the Bukhar-Zhyrau district), mercury was detected in the highest amount in fish from Lake Balkhash, at 0.009±0.001 mg/kg. Accumulation of residual amounts of radionuclides in the Akmola region was noted in fish from all the studied reservoirs, in the Karaganda region, fish in most cases were free of radionuclides.