production agricultural production
It is well known that unauthorized commercial activity is currently in progress at the Site territory where many areas contaminated with radiation are present. Such activities include, for instance, uncontrolled pasturing and production of agricultural products. Total about 80 operating winterings were revealed within SNTS perimeter mainly involved in sheep, horse and cattle breeding as well as fodder production. There are over 30,000 heads of sheep, 4,000 - cattle and 3,000 horses at the Site.
Radiological quality assessment for agricultural products performed at winterings Dostyk and Bayan Sor located in close vicinity of contaminated with radiation testing pad “4a” (a place for testing of combatant radioactive substances) showed that intake of 137Cs and 90Sr with food by the cattle does not result in exceeding of the permissible levels in the main types of products (beef, mutton, cow's milk) and does not impose hazard on people. At that, the mandatory condition for safety of food products produced at Bayan Sor wintering is exclusion of pasturing at areas contaminated with radiation (testing pad “4a”) since, at relatively small area of such contaminated spot comprising just about 0.1% of all pasturing lands there, this particular contaminated spot, in case of uniform consumption of vegetation from all pasture lands in vicinity of the wintering, would contribute to contamination of agricultural products.
Studies of intake and re-distribution of radionuclides in agricultural animals show that 137Cs concentration in organs and tissues of sheep fed at SNTS lands depends on duration of such intake with food. Regarding 90Sr, it is not accumulated in meat, liver, kidneys, lungs or hurts even at feeding of animals by vegetation with specific average 90Sr activity of up to 9.5×104 Bq/kg and at total intake of over 33×106 Bq while boned are accumulators. Contents of 3H in all organs and tissues quickly reaches equilibrium state and is re-distributed depending on water content in organs or tissues, i.e. milk of an animal continuously fed on contaminated with 3H lands would have 3H concentrations close to its content in the source (water, vegetation).
Concentration of 3Н Shagan river water taken 4.7 km downstream of Atomic Lake reaches the values up to 1.6×105 Bq/kg. Control over 3H presence in agricultural products performed in 6 farms located along the Shagan River showed that 3H contents in all milk samples lies within the regulatory limit of 7,700 Bq/kg (Radiation Safety Norms doc NRB-99)and varies from 12 Bq/kg in Toraygyr wintering to 5,500 Bq/kg in Yubileinaya wintering. Nevertheless, registered high concentrations of 3H in milk samples taken in Yubileinaya and Sarapan winterings (300 Bq/kg) require more detailed study of these facts.
Our studies showed the need in restriction of access to areas contaminated with radioactivity at the testing grounds Opytnoye Pole, BRV, Balapan, Sary Uzen, Degelen, to Atomic Lake, Telkem-1 and Telkem-2; it is necessary to establish a science-based system of control over agricultural products of the SNTS.