Chemicals of Emerging Concern Measured in Roof-Harvested Rainwater to Inform Environmental Justice Communities

Abstract

The unregulated development of various human activities such as industry, agriculture, and transport result in adverse environmental consequences. In the early 2000s, the global production of human-made chemicals was 400 million tons each year. Over 50% of these chemicals' total production is considered environmentally harmful compounds, and 70% of those chemicals have a significant environmental impact. Chemicals of emerging concern (CECs) encompass a wide range of human-made chemicals (such as pesticides, personal care products, industrial compounds, among others) used worldwide and indispensable for modern society. However, many of these chemicals have no enforced regulatory standard. In the last decade, CECs have been detected at low levels in the environment, including surface water, drinking water, soils, and precipitation rain and snow. CECs wide prevalence in the environment makes them potential candidates for future regulation depending on their toxicity and frequency of detection in the environment. Due to global water scarcity concerns and population growth, alternative water sources and conservation efforts are critical, especially in arid and semi-arid regions of the planet. The ancient practice of harvesting rainwater is becoming more common, and as this practice grows, so does interest in the quality of harvested rainwater. This thesis measured CECs in roof-harvested rainwater collected by citizen scientists over three years. The goal was to determine whether harvested rainwater is a viable method for community members to offset their dependence on existing water supplies. All measurements were below currently available U.S. Environmental Protection Agency Primary Drinking Water Standards. This finding indicates that the quality of the roof-harvested rainwater is viable for non-potable domestic use in Arizona communities. However, due to the nature of CECs, ecological and human health risk-based standards currently do not exist for all measured compounds for comparison. Due to these data and policy gaps, ongoing investigations, and efforts to protect water sources are essential.