CARERC Pilot: Surface Water Monitoring for Contaminants of Emerging Concern (CECs) in Four Kentucky Watersheds

1. Prevalence of Contaminants of Emerging Concern (CECs) in the Natural Environment: Common use pesticides (CUPs) and pharmaceuticals, while important for agricultural productivity and human daily usage, have become ubiquitous in waterways worldwide, resulting in significant effects on agroecosystem food webs (e.g., honey bee colony collapse) and human health (e.g., reproductive and development disruption, carcinogens, antibiotic resistant genes)1,2. Exposure to specific CUPs, such as imidacloprid, in runoff waters and antibiotic residues contained in livestock manure and wastewater, such as tetracycline, lincomycin, chlortetracycline, and sulfamethazine, may influence the population structure of denitrifying bacteria communities3–6 and thus the activity of microbial denitrification in adjacent wetland treatment systems, which is a critical removal pathway for nitrate-N and in part controls toxic algal blooms. CUPs and pharmaceuticals are important CECs present in agricultural and urban landscapes and their associated aquatic ecosystems. Both are routinely detected in various environmental matrices, including confined animal feeding operation (CAFO) wastewater and CAFO lagoon solids, straight pipes into streams, and groundwater and surface water from intensely agricultural and urbanized watersheds. Further, little is known about CEC fate and transport in streams and exposure to humans using downstream water for drinking sources. The environmental consequences of these contaminants of emerging concern (CECs) are only now being investigated. Therefore, the goal of this project is to monitor recreational CEC exposure trends for 6 months in four distinct land use regions (urban, agricultural, mining, and forested) during 2022. Analyzed CECs will include pesticides (including glyphosate, 6-CAN, acetamiprid, azoxystrobin, clothianidin, dimethoate, dinotefuran, imidacloprid and byproducts, metalxyl, picoxystrobin, pyraclostrobin, sulfoxaflor, thiacloprid, picoxystrobin, thiamthoxam urea, and trifloxystrobi) and pharmaceutical and personal care products (including 1,7-Dimethylxanthine, acetaminophen, ampicillin, azithromycin, azithromycin, caffeine, carbazepine, cefatoxime, ciprofloxacin, clarithromycins, clinafloxcin, clarithoromycin, clinafloxacin, codeine, cotinine, danofloxacin, dehydronifedipine, digoxigenin, digoxin, diltiazem, diphenhydramine, enrofloxacin, erythromycin, flumequine, fluoxetine, lincomycin, lomefloxacin, miconazole, norfloxacin, norgestimate, ofloxacin, ormetoprim, oxacillin, penicillin G, penicillin V, penillic acid, phenazone, roxithromycin, sarafloxacin, sucrolose, sulfachlorpyridazine, sulfadiazine, sulfadimethoxine, sulfamerazine, sulfamethoxazole, sulfanilamide, sulfathiazole, thiabendazole, and trimethoprim.). 2. Field Sampling: Monthly sampling campaigns will be conducted at the four field sites (Lexington (urban), Princeton (agricultural), Kermit (mining), and Clayhole (forested)) from March to October 2022 to identify and characterize seasonal common CEC loads in recreational rivers that are used for drinking water sources downstream. Polar organic chemical integrative samplers (POCIS) will be placed in the middle of the streams to allow water to flow through the passive samplers. POCIS are passive samplers that enable time weighted average concentrations of CECs to be measured and then adjusted based on stream flow to provide CEC load estimates. POCIS samples will be analyzed using methods developed by Magalhaes et al. (2009)7 and EPA 1694 methods8 to characterize potential contaminant mixtures. Water chemistry properties of the surface water at the field sites will be characterized monthly using of a YSI handheld meter. Additionally, monthly grab water quality samples will be analyzed for nitrate-N, orthophosphate-P, total N, bromide, heavy metals, E. coli, and dissolved organic carbon (DOC) in addition to CECs monitored using POCIS. Contaminant loading in the streams will be determined using nearby USGS gauge stations or water table monitoring dataloggers to determine flow rate through the sites and a SonTek RiverSurveyor to measure flow velocities and geometric channel dimensions during high and low flow events to create discharge curves.