Contaminant Exposure and Transport from Three Potential Reuse Waters within a Single Watershed

Area of Science:

• Environmental Chemistry
• Water Reuse
• Contaminant Hydrology

Background:

• Growing demand for safe water necessitates evaluating contaminant exposures from water reuse.
• Wastewater effluent, urban stormwater, and agricultural runoff are key sources of surface water contamination.

Purpose of the Study:

• Compare contaminant loads from wastewater effluent, urban stormwater, and agricultural runoff.
• Assess the impact of wastewater-effluent irrigation on contaminant levels in agricultural runoff and crops.

Main Methods:

• Analyzed organic chemical contributions from three water reuse sources to surface water.
• Quantified contaminant loads and concentrations in water samples and harvested corn.
• Utilized targeted organic chemical analysis, including pharmaceuticals and PFAS.

Main Results:

• Wastewater effluent, urban stormwater, and agricultural runoff all contribute significant and varied organic chemicals.
• Urban stormwater's episodic organic loads often exceeded daily wastewater effluent loads, excluding disinfection byproducts.
• Wastewater-effluent irrigation minimally impacted agricultural runoff, with only imidacloprid and estrone showing differences; trace antibiotics were found in irrigated corn plants.

Conclusions:

• Water reuse sources contribute diverse organic chemicals to surface waters, with urban stormwater posing a significant episodic threat.
• Wastewater-effluent irrigation of crops presents a low risk for widespread contaminant transfer to runoff and harvested products.
• Further research on specific chemical fate and transport in agricultural systems is warranted.