Water samples were collected at the test tank daily for the first month and every Sunday in plastic bottles and stored at 40C, and transported weekly to the laboratory at the Military Institute of Medicine and Pharmacy, Military Medical University to determine the concentration of HMs o Intervention supervision: The content and procedure of the experiment intervention in the laboratory (6 months) and in the field (18 months) were supervised by principal researchers and researchers of the Military Medical Research Institute, Military Medical Academy.