Effects of CaCl2 and CaBr2 on the fecundity of Planorbarius corneus L.

Saturated water solutions of calcium chloride (481.3 g CaCl2/L) and calcium bromide (1065.9 g CaBr2/L) and their mixtures, commercially prepared as “high density brines”, are regularly used during special operations in exploration and production of natural gas and crude oil. After operations, all workover fluids are left in the environment as waste. In the present study, the effects of several sublethal concentrations of these solutions (CaCl2 1202 ppm, 2403 ppm and 4796 ppm, CaBr2 1065 ppm, 2663 ppm and 5325 ppm, 1:1 volume mixture 773.9 ppm, 1931 ppm, 3855 ppm and 5779 ppm) on the fecundity of the freshwater snail Planorbarius corneus L. were laboratory tested. During the six week exposure a considerably reduced fecundity was found. The tested CaCl2• solution concentrations reduced fecundity by 53.9–84.4 %, CaBr2 by 72.3–90.8 % and the mixture by 72.5–94.0 % compared with the control groups.