Veterinary pharmaceutical products used to treat parasites in farm animals such as cattle, sheep, pigs, and poultry have been discovered in nearly a quarter of the drinking-water systems investigated as part of a cutting-edge study.
The four-year research project examined more than 100 drinking water systems in Ireland and discovered varying levels of veterinary pharmaceutical compounds in 24% of them. It was funded by the Irish Centre for Research in Applied Geosciences through Science Foundation Ireland. Its findings are published in the latest edition of the Teagasc journal, TResearch.
“We are highlighting the fact that these compounds need more examination in terms of determining what is a safe level,” said the author of the report, researcher Damien Mooney, a PhD student at Trinity College, who is working on the project in conjunction with Teagasc.
Usage of such compounds was set to increase as a result of climate changes and changes in farming practices, he warned, adding that: “This could see an increased level of these compounds in our groundwater.
“We need to have more definitive guidelines on safe levels of these compounds in the ground water.”
The findings are a cause for concern, he said, because the increased intensification of food production systems in Ireland and Europe have meant that veterinary pharmaceuticals have become a critical component in animal husbandry. Up to 90% of an administered dose can be excreted by the animal into the environment.
The use of such products can, warns the study, potentially lead to their occurrence in environmental waters, such as groundwater — and in Ireland, groundwater accounts for approximately 26% of the public and private drinking supply, with some regions relying on groundwater for up to 75% of their drinking water.
Up to now there have been no suitably sensitive, comprehensive, analytical methodologies for detecting such contaminants at environmentally relevant concentrations but the research project developed methods of finding them.
The study then investigated the presence in groundwater of two groups of veterinary pharmaceuticals commonly used in Irish agriculture, anthelmintics, used to treat parasitic worms in food-producing animals and anticoccidials, used primarily in poultry production for the treatment of coccidiosis, an intestinal parasitic disease.
The research focused on veterinary pharmaceuticals because they are used in high amounts in Ireland and there was currently very little known about their impact on the environment, said Mr Mooney.
While checks are routinely carried out for the presence of such veterinary products in food, he explained, large amounts of these products were naturally excreted by the animals into the environment and there was a lack of regulation about acceptable levels of these compounds in groundwater.
“Prior to this, the available technology was not sufficiently sensitive or comprehensive to detect these residues in the environment,” he said.
“At a scientific level, there is a lot more focus on the use of a wide range of chemicals which end up in our water systems.
“One of the biggest implications of this study is that it has developed two comprehensive and highly sensitive technologies to detect these compounds in water.
“These can now be used to determine if they are present or not,” he said, adding that the new technology could, in the future, be used to examine the presence of a much wider range of chemicals in groundwater.