Trihalomethanes in Onondaga Lake

Chloroform and bromodichloromethane were detected in Onondaga Lake of Syracuse, New York, with average concentrations of 0.085 µg/L and 0.0085 µg/L respectively. The sewage treatment plant is the major contributor (60%) to THM loading. Onondaga Creek contributes about 30% of loading. Ley Creek and Harbor Brook are minor contributors. Other tributaries make negligible contributions. A mass balance model and a wind driven volatilization model are used to show that volatilization is the major loss process of THMs in Onondaga Lake. Trichloroethylene was also detected in Ley Creek, emanating from the South Branch.