Investigation of the correlation between trihalomethane concentrations and socioeconomic factors in NY State

Recent environmental justice studies have found associations between low drinking water quality and socioeconomic indicators such as income and race. Trihalomethanes, probable human carcinogens, are commonly found disinfection by-products (DBPs) in public water systems (PWS). Although trihalomethanes are correlated with socioeconomic indicators, there is a knowledge gap regarding how the level of contaminants correlates with socioeconomic indicators and other physicochemical factors in specific regions. Therefore, we investigated the correlation between trihalomethane concentrations and socioeconomic factors in New York State with more practical and insightful data analysis and interpretation compared to those in previous studies by providing more detailed city-level data and water system characteristics affecting the correlation. We found a negative correlation between median household income and trihalomethane concentrations in the state. The communities served by PWS using groundwater sources had lower trihalomethane concentrations and higher household income, suggesting that water quality parameters contribute to the negative correlation between trihalomethanes and income levels. The inverse association between trihalomethanes and household income may indicate socioeconomic disparity regarding drinking water quality and the need for improved efforts to assist small- and medium-sized community water systems to lower DBP levels in New York State because small- or medium-sized systems may have fewer resources to apply DBP control and removal technologies compared to large systems.