Survey of gross beta radioactivity in surface waters of the Midland, Michigan area (lake Huron and the Chippewa, Pine, and Tittabawassee rivers)

Measurements of Lake Huron water as supplied to the Midland location of the Dow Chemical Company over the period 1970–1981 show that a mean concentration of ≈ 3 pCi/L gross beta activity held relatively constant with a range of yearly mean values from 2 to 4 pCi/L and a range of individual values from 1 to 7 pCi/L. This is comparable to observed values for other Great Lakes' waterways reported in the litarature. There was no apparent seasonal fluctuation. Midland area river water for 1967–1981 show median values of 3 to 4 pCi/L and a range of 2 to 11 pCi/L, comparable to those reported in the literature from througout the United States. The observed activity concentrations in the water are well below the limits of the EPA drinking water standards.