Chloride Concentrations in Meromictic and Holomictic Lakes and Calculating Chloride Concentrations Using Specific Conductivity

Abstract

Chloride is a crucial part of water quality sampling because in high concentrations it can negatively impact surface waters by changing the mixing pattern of lakes. Electric conductivity is usually a representation of salinity, so a close correlation between electric conductivity and chloride is expected. The purpose of this study is to (1) compare chloride concentrations in the epilimnion and hypolimnion between meromictic and holomictic lakes (2) and develop a relationship between chloride concentration and electric conductivity, as a prediction tool, for surface waters in the Twin Cities Metro Area (TCMA). Fourteen lakes in the TCMA, three meromictic and 11 holomictic lakes, were used in this study. Water samples were collected using a composite tube and Kemmerer and analyzed for chloride concentrations, and specific conductivity was determined using a Hydrolab Minisonde Multiprobe. Linear, polynomial and power regression models were used to describe chloride concentration as a function of specific conductivity. Results indicated that chloride concentrations are lower in the epilimnion and higher in the hypolimnion in both meromictic and holomictic lakes, but there is a more significant difference between surface and bottom concentrations in meromictic lakes. Also, the polynomial regression model most accurately estimated chloride concentrations using specific conductivity.