The transfer of 137Cs and heavy metals to tissues within the organs of snails.

This paper describes the dynamics of 137Cs accumulation and its concentration ratio as well as that of some stable elements in the body, shell, gastrointestinal tract and albumin gland of a particular species of snail (terrestrial gastropod), namely the Giant African snail (Lissachatina fulica), after the long-term ingestion of contaminated forage and/or soil. The activity concentration of 137Cs in the their bodies increased over the first 40 days of the experiment, after which the increase in the activity of this radionuclide significantly reduced. The distribution of 137Cs in the body of a snail decreases as follows: gastrointestinal tract ˃ body = albumin gland ˃ shell. It was found that the contribution of soil towards the contamination of their bodies by 137Cs is far less than that of forage. Although the biological availability of Pb and U in forage is one order of magnitude higher than in soil, the main contribution to the contamination of snails originates from soil.

Studying the concentration of xenobiotics in milk and developing the biosensor method for their rapid determination.

In this article the content of toxic xenobiotics (heavy metals and pesticides) in cow milk collected from 5 districts of Eastern Kazakhstan was examined and their cumulative properties were determined. The content of organochlorine pesticides (HCCH, DDT) was not detected in the analyzed milk. The content of mercury and arsenic in milk samples does not exceed the maximum allowable concentration (0.005 and 0.05 mg/kg, respectively). The content of cadmium above the maximum allowable concentration (0.03 mg/kg) was found in milk sampled from Shemonaikha and Katon-Karagai districts. The content of lead and zinc above the maximum allowable concentration (0.1 and 5.0 mg/kg, respectively) was found in milk samples taken from all 5 studied districts. The content of copper above the maximum allowable concentration (1.0 mg/kg) was found in milk samples collected from 4 districts under study (Borodulikha, Beskaragai, Shemonaikha and Katon-Karagai). Based on the analysis of information data the need to develop an accelerated method of determining toxic xenobiotics in milk was substantiated. The basic directions of modernization of the biosensor for determination of cadmium and lead salts in milk and dairy products were selected. A new approach to the process of immobilization of the enzyme on the surface of a substrate for cadmium and lead salts determination in milk has been developed. The efficiency of using a polymeric plate with a graphite conducting layer as a basis for the enzyme biosensor was established.