Drinking water must be disinfected for pathogen control prior to distribution to the public. Chlorine has been used as a disinfectant in public drinking water supplies for the greater part of this century.⁹ More than twenty years ago, it was recognized that chlorine reacts with the DOC and bromide present in natural waters to form a variety of halogenated byproducts potentially harmful to human health.² Many of these halogenated compounds are suspected of being carcinogenic and teratogenic (capable of causing malformations in the unborn fetus.) The most abundant class of byproducts, trihalomethanes (THM; chloroform, bromodichlormethane, dibromochlormethane, and bromoform) are regulated in finished drinking water.³ However, current levels of THM and other dangerous byproducts (DBP) in drinking water may cause chronic health risks which has increased interest in decreasing the level of these components in drinking water.¹⁰

The environmental factors that determine the extent to which a particular source water forms THM or other DBP on chlorination are the concentration of bromide (Br ^-) which is controlled by the proximity of the water source from seawater sources, the amount of DOC present in the water, and the molar reactivity of the particular composition of DOC with respect to THM and DBP formation.¹¹ Natural water contains a total DOC that contains many constituents compounds. Although it is not generally known, the DOC composition can differ substantially depending on the source of the water. This variability in DOC composition dramatically affects its reactivity to form THM and other DBP. As a result, only some of the components of DOC are thought to contribute to THM and DBP formation. Most research indicates the DOC compounds responsible for THM formation are phenolic constituents.^{12, 2}

In light of the changing regulatory environment, the water quality community seeks information about the sources of THM and other DBP forming DOC within the Delta, and possible management strategies for reduction or diversion of problematic sources. This request requires methods to characterize the types and amount of constituents in DOC samples collected from different regions throughout the Delta. Very few analytical methods can provide this type of DOC characterization. One type of analysis which can provide this type of detailed qualitative and quantitative information is Nuclear Magnetic Resonance Spectroscopy (NMR). Our work is focused upon utilizing this powerful technique to answer questions surrounding the Delta water quality issue.