Growing number of studies detect antibiotics, medicines and caffeine in groundwater

Production and use of medicines, antimicrobial and pharmaceutical products, is increasing globally – along with the risk of their ingredients and breakdown products reaching the environment. The effects of such contamination may carry both human and ecosystem health risks. Antibiotics in soil and water, for example, enhance the development of antibiotic resistant bacteria. And while effective waste-water treatment can remove many chemicals, other products whose removal proves more difficult  may still reach soil and water via treated or untreated wastewater. Other sources of manufactured compounds that enter surface waters and groundwater include effluent from hospitals, landfill sites and aquaculture.

Although surface waters (rivers and lakes) are most likely to be contaminated, it is crucial to assess the risk to human health and environment from contaminants in groundwater, say researchers in a new literature review. Not only is there less potential for breakdown through oxidation in groundwater compared to freshwater, but some populations rely on it to meet water needs. Groundwater in some geologies, such as karst (e.g. limestone), has indeed been shown to collect undegraded pollutants such as anti-inflammatory drugs and pesticides. A survey of nearly 600 aquifers in France in 2013 found that a third were badly affected by chemical contamination¹. Meanwhile, some rivers are recharged by groundwater – bringing any pollutants with it.

Researchers conducted a literature review of studies from all world continents on contamination of groundwater with these products. Detection technologies (such as gas chromatography and high-performance mass spectrometry) are steadily advancing, they note, and available evidence on levels in groundwater is growing. Such data can contribute to understanding how these substances – recognised as contaminants of emerging concern – enter the environment and inform policies related to safe disposal of products.

The review finds that traces of pharmaceutical compounds – including analgesics, antibiotics, lipid regulators and beta blockers – have been found in groundwater all over the world. Some outliers in the data – extremely high concentrations – can usually be traced to a source near the sampling site, for example a landfill site in India was linked to peak concentrations of diclofenac (an analgesic) of 1.4 million nanograms (ng) per litre (ng/l).

Comparing data from the USA, Switzerland, Taiwan, Nigeria, Spain and India, the latter two countries had the highest levels of antibiotics, beta-blockers and lipid regulators in groundwater, according to the review. It is possible that these findings are due to sampling effort, the researchers note. High levels of carbamazepine (an anti-epileptic) have been found in studies of both US and European groundwater, at 1 000 ng/l and 2 300 ng/l – as has caffeine (over 14 000 ng/l).

Studies published in the last four years show that triclosan and triclocarbon (antibacterials) are commonly found in groundwater in many countries. The insect repellent diethyltoluamide (DEET), meanwhile, is ubiquitous in European groundwater². Contamination hotspots in developed countries are usually close to waste-water treatment plants, pharmaceutical and chemical factories, landfill sites and farmland, say the researchers.

Overall, there is growing evidence that groundwater in all parts of the world is affected with contaminants of emerging concern. The researchers suggest that greater understanding of the transport of personal care products and pharmaceuticals in soil and water would be vital to determine their fate in groundwater, requiring the development of tracing methodologies amongst others. Policies to prevent harmful contamination and remediation measures may also draw on this growing body of knowledge, they add.

Footnotes:

1. Baran, N., Surdyk, N. and Auterives, C. (2021) Pesticides in groundwater at a national scale (France): Impact of regulations, molecular properties, uses, hydrogeology and climatic conditions. Science of The Total Environment, 791:148137.
2. Bunting, S.Y., Lapworth, D.J., Crane, E.J. et al. (2021). Emerging organic compounds in European groundwater. Environmental Pollution, 269:115945.

Source:

Silori, R., Shrivastava, V., Singh, A., Sharma, P., Aouad, M., Mahlknecht, J. and Kumar, M. (2022) Global groundwater vulnerability for Pharmaceutical and Personal care products (PPCPs): The scenario of second decade of 21st century. Journal of Environmental Management, 320: 115703.

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“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.

Notes on content:

The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.