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 contamination. Meanwhile, some rivers are recharged by groundwater – bringing any pollutants with it.