The Occurrence and Behavior of Halomethanes in the Aquatic Environment

摘要

This study was conducted to determine the impact of the release of halomethanes produced during the chlorination of wastewater that was discharged into the Red Cedar River. The levels of chloroform in sewage were monitored as it passed through the East Lansing sewage treatment plant. The production of halomethanes during chlorination was demonstrated by an increase from <1.0 micrograms/l to 16.0 micrograms/l chloroform following chlorination of tertiary treated sewage. The Red Cedar River was sampled and analyzed for halomethanes. The development of a sewage tracer was investigated to provide a means to differentiate changes in haloform levels in the river due to dilution from those occurring as a result of volatization or adsorption. The methods researched were neutron activation analysis of europium, dysprosium and bromine, as well as a fluorescence and chloride ion tracer. The neutron activation methods were the most sensitive, with limits of detection of 1.0 micrograms/l dysprosium and 35.0 micrograms/l europium. Laboratory controlled haloform/oxygen gas transfer and adsorption experiments were conducted to predict the persistence of haloforms in a river system. Oxygen to haloform gas transfer ratios and a measured log sediment-water partition coefficient were used to calculate Red Cedar River haloform volatization half-lives.