Effect of Changes in Acidity and Salinity on the Octanol Water Partition Coefficient of Monomethylmercuric Species Present in Aquatic Environments at High pE.

摘要

The octanol/water partition coefficient (Kow) of methylmercury was determined at pH 7 in water and in aqueous solutions ranging from 0.0003 M to 0.6000 M in sodium chloride. It was also determined over a pH range of 2 to 10 with a fixed sodium chloride concentration of 0.0045 M. In these experiments, Kow was seen to increase with increasing chloride concentrations in the range 0.0 to 0.075 M, with the sharpest increases in the range 0.00 to 0.01 M. Kow was seen to decrease as the pH increased from 5 to 8. Results were similar whether low levels of methylmercuric chloride or methylmercuric hydroxide were used as the starting materials. Partitioning was not affected by changes in ionic strength in the range 0.01 to 0.6 M. Changes in partitioning behavior are attributed to an exchange of chloride and hydroxide anions on the methylmercuric cation.