Title: Emerging organic contaminants arising in rural environments: investigations in karst and fractured bedrock
Researchers: Damien Mooney, Dr Catherine Coxon, Dr Karl Richards
Emerging organic contaminants (EOCs) are becoming more and more of a growing international concern with respect to their occurrence in groundwater bodies. EOC is a term used to describe both newly developed compounds and newly discovered compounds present in the environment. Some examples of the most common EOCs include pesticides, veterinary drug products and pharmaceutical and personal care products (PPCPs), often with respect to both the parent compound and any metabolites or transformation products (TPs)
The administration and application of such pharmacologically active chemicals can potentially lead to the occurrence of such compounds in groundwater bodies. Potential entry routes to groundwater include both point source contamination (e.g. farmyard wastes, leachates from agricultural land and from animal holding, feeding and waste storage areas and septic tank effluent discharge) and diffuse source contamination (e.g. spreading of fertilisers and pesticides). In addition there are a number of geological factors such as overlying soil and underlying aquifer properties, which can affect the movement of contaminants into groundwater. The nature of Irish bedrock aquifers (with fracture permeability and no significant primary permeability, and the widespread occurrence of karstification in Irish limestone aquifers) may facilitate transport of such contaminants through the unsaturated and saturated zones, without sufficient attenuation.
Given the high demands on the performance of Irish agriculture in terms of the food production system, in addition to the imminent pressures attributed to the fast approaching Harvest 2020 and more recent FoodWise 2025, heavy usage of veterinary drugs is set to continue, if not increase. As a result, loss of veterinary products such as anti-parasitic agents to underground water is not only a matter of international scientific interest, but also a matter of public concern. This project will fill the void in current research which lacks any insight into the occurrences of emerging organic veterinary contaminants in Irish groundwater, thus representing an important advancement in the knowledge and understanding of Irish groundwater quality. Not only will the project help assess whether or not anti-parasitic drugs are an issue in Irish ground water, it will also contribute to evaluating environmental effects of Food Harvest 2020 and Food Wise 2025 in terms of investigating such potential rural groundwater concerns, which may not previously have been considered adequately in an Irish context.
One of the main project hypotheses is as follows:
• Veterinary drugs, in particular anthelmintics, anticoccidials and/or pyrethroids, and their transformation products, are occurring in Irish groundwaters The other hypotheses, as listed below, are either categorised as spatial or temporal patterns, with the hypotheses created with consideration to the water framework directive’s (WFD) source pathway receptor (SRP) approach. Spatial patterns
• Agro-chemicals and their transformation products are more likely to occur in groundwater in regions where high usage is expected, e.g. where intensive dairying is carried out or where landspreading of manures from intensive poultry units is carried out.
• The occurrence of agrochemicals in Irish groundwaters is associated with certain physical characteristics of the catchment. For example, these compounds are more prevalent in karst aquifers due to the intrinsic vulnerability whereby contaminants can be carried overland and enter groundwater via karst features such as swallow holes / sinking streams. Temporal patterns: • Temporal variations in agrochemical occurrence in groundwater are influenced by timing of agricultural practices, such as when animals are housed versus on pasture.
• Temporal variations are also influenced by climatic conditions and timing of groundwater recharge, in addition to the flow regime within the aquifer. The aim of this project is to investigate the occurrence of synthetic organic compounds arising from rural activities in Irish karst and fractured bedrock aquifers. The primary focus will be on the loss to groundwater of up to three main groups of anti-parasitic veterinary agents (anthelmintics, anti-coccidials and/or pyrethroid insecticides), which represent the most widely use veterinary drugs in Irish agriculture production.
Project objectives include:
• Investigation of the frequency of occurrence of different compounds and its relationship to the chemical characteristics of the compounds. Such compounds will include both parent compounds and some additional transformation products (TPs) where appropriate
• Investigation of source factors ( point source and diffuse source) involved in contaminant detections (e.g. farmyards and animal waste storage, land spreading of manures and slurries, animal grazing and animal feeding locations)
• Investigation of pathway factors involved in the occurrence of contaminants (e.g. characteristics of soil, Quaternary deposits and bedrock and to also include any seasonal aspects)