Persistence of Brine Pollution in Fresno, California Aquifer

Chloride and sodium pollution of the Fresno, Calif., aquifer was discovered in 1953 downgradient of seepage pits and wells used for wastewater disposal. An ice plant and a water softening plant in the area were the pollution sources. A plume of polluted groundwater was delineated, and the source discharges were stopped in 1953. Sampling in the late 1970's indicated that high sodium and chloride concentrations were still present in the aquifer. The population at risk, those on sodium restricted diets, were alerted by health authorities, and the impact was felt primarily by this segment.