Abstract
The timely identification of areas where man-made radionuclides migrate through water streams is highly important for the territory of the former Semipalatinsk Test Site since the aquatic environment is currently a source of secondary contamination of environment. This article presents research findings on radioactively contaminated Lake Kishkensor located at the Semipalatinsk Test Site territory. As a result of this research, a new locally contaminated spot was discovered in the vicinity of the "Balapan" test site. Lake Kishkensor was found to be contaminated with man-made (3)H and (90)Sr. The (3)H activity concentration in surface waters reached 430 kBq/L, and the concentration of (90)Sr reached 100 Bq/L. In the sediments, the (3)H activity concentration reached 700 kBq/kg, while that of (90)Sr and (239+240)Pu reached 310 Bq/kg and 250 Bq/kg, respectively. Ground water was found to be a source of surface water and sediment contamination. The monitoring results showed that the contamination level of the lake largely depended on the season and the inflow of contaminated ground water.