Sources and haloacetic acid/trihalomethane formation potentials of aquatichumic substances in the Wakarusa River and Clinton Lake near Lawrence, Kansas

Gram quantities of aquatic humic substances (AHS) were extracted from the W akarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentration s of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAAS ) and trihalomethanes (THM4) that exceed U.S. Environmental Protection Agen cy(EPA) Maximum Contaminant Levels (MCL) in drinking water. AHS from the Wa karusa River and Clinton Lake originated from riparian forest vegetation, r eflected respective effects of soil organic matter and aquatic algal/bacter ial sources, and bore evidence of biological degradation and photodegradati on. AHS from the Wakarusa River showed the effect of terrestrial sources, w hereas Clinton Lake humic acid also reflected aquatic algal/bacterial sourc es. Greater amounts of carbon attributable to tannin-derived chemical struc tures may correspond with higher HAAS and THM4 yields for Clinton Lake fulv ic acid. Prior to appreciable leaf-fall from deciduous trees, the combined (humic and fulvic acid) THM4 formation potentials for the Wakarusa River ap proached the proposed EPA THM4 Stage I MCL of 80 mug/L, and the combined TH M4 formation potential for Clinton Lake slightly exceeded the proposed THM4 Stage II MCL of 40 mug/L. Finally, AHS from Clinton Lake could account for most (>70%) of the THM4 concentrations in finished water from the Clinton Lake Water Treatment Plant based on September 23, 1996, THM4 results.