An investigation of anticoccidial veterinary drugs as emerging organic contaminants in groundwater

• Published in: The Science of the total environment Vol. 746; p. 141116
• Main Authors: Mooney, D., Richards, K.G., Danaher, M., Grant, J., Gill, L., Mellander, P.-E., Coxon, C.E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2020
• Subjects: Coccidiostats; Emerging contaminants; Feed additives; Groundwater; Ionophores; Poultry production; Coccidiostats; Feed additives; Groundwater; Emerging contaminants; Ionophores; Poultry production
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.141116

Intensification of the food production system to meet increased global demand for food has led to veterinary pharmaceuticals becoming a critical component in animal husbandry. Anticoccidials are a group of veterinary products used to control coccidiosis in food-producing animals, with primary prophylactic use in poultry production. Excretion in manure and subsequent land-spreading provides a potential pathway to groundwater. Information on the fate and occurrence of these compounds in groundwater is scant, therefore these substances are potential emerging organic contaminants of concern. A study was carried out to investigate the occurrence of anticoccidial compounds in groundwater throughout the Republic of Ireland. Twenty-six anticoccidials (6 ionophores and 20 synthetic anticoccidials) were analysed at 109 sites (63 boreholes and 46 springs) during November and December 2018. Sites were categorised and selected based on the following source and pathway factors: (a) the presence/absence of poultry activity (b) predominant aquifer category and (c) predominant groundwater vulnerability, within the zone of contribution (ZOC) for each site. Seven anticoccidials, including four ionophores (lasalocid, monensin, narasin and salinomycin) and three synthetic anticoccidials (amprolium, diclazuril and nicarbazin), were detected at 24% of sites at concentrations ranging from 1 to 386 ng L−1. Monensin and amprolium were the two most frequently detected compounds, detected at 15% and 7% of sites, respectively. Multivariate statistical analysis has shown that source factors are the most significant drivers of the occurrence of anticoccidials, with no definitive relationships between occurrence and pathway factors. The study found that the detection of anticoccidial compounds is 6.5 times more likely when poultry activity is present within the ZOC of a sampling point, compared to the absence of poultry activity. This work presents the first detections of these contaminants in Irish groundwater and it contributes to broadening our understanding of the environmental occurrence and fate of anticoccidial veterinary products. [Display omitted] •Anticoccidial veterinary drugs are emerging groundwater contaminants of concern.•Sites sampled for anticoccidials accounted for land-use and hydrogeological factors.•Seven of twenty-six compounds were detected, most frequently the ionophore monensin.•Amprolium and other coccidiostats are documented in groundwater for the first time.•Poultry activity is a significant driver of anticoccidial occurrence in groundwater.