World Water Day: six pollution threats the world must fix to save vital groundwater
World Water Day has arrived this year with a stark warning from the United Nations: “We must protect groundwater from pollution and use it sustainably.”
Groundwater currently provides half of our drinking water, more than 40 per cent of irrigation water and a third of industry’s needs, but experts warn it is becoming both increasingly scarce and dangerously polluted. To mark this year’s World Water Day - and reflect LGC’s expertise in developing quality reference materials to analyse pollution in watercourses and the wider environment - we outline six of the biggest threats to groundwater quality in 2022.
1. Pharmaceutical and veterinary residues
Veterinary medicines concentrated in manure and slurry can transfer to farmland and crops via manure spreading, leading to surface and groundwater contamination. This in turn builds up residues in aquatic animals and also contributes to the problem of antimicrobial resistance.
Human medicines are another growing source of water contamination, with waste from medications including antidepressants increasingly polluting the urban water cycle, rivers, and oceans. In response to at least part of the problem, the European Union introduced new regulations aimed at restricting the use of veterinary antimicrobials in January.
The United Nations Environment Programme (UNEP) has reported that the impact of microplastics on soils, sediments and freshwater could be between four and 23 times higher than the much-publicised effects of plastic pollution on the world’s oceans. UNEP was quoting German research which calculated that one third of all plastic waste ended up in soils and freshwater, while another study concluded that more than 700,000 microscopic plastic fibres are released into the aquatic environment from each washing machine cycle.
According to LGC AXIO Proficiency Testing’s water specialist Rita Sharma, new regulations for microplastics in river water are currently in the pipeline, although effective monitoring could still be years away.
3. Synthetic dyes
Man-made dyes are amongst the most significant causes of water pollution worldwide, with an estimated 17-20 per cent of industrial water pollution blamed on fabric dyes and treatments. In leading garment-producing countries such as Bangladesh and Indonesia, dye-contaminated wastewater is commonly dumped directly into rivers and streams, releasing a cocktail of potentially carcinogenic chemicals, upsetting aquatic life and rendering the water undrinkable.
Scientists have long been working on methods to help remove dyes from water sources, with some – such as carbon nanotubes functionalised with the amino acid L-tyrosine – recently showing promise.
Around the start of the 21st century, the US Environmental Protection Agency (EPA) began describing nitrosamines – highly carcinogenic, largely man-made compounds formed by combinations of amines and nitrogen structures - as an “emerging contaminant group”. Nitrosamine water contamination has been linked to wastewater treatments, including chlorine and resins, as well as metal and cosmetics manufacturing and rocket fuel – prompting the EPA to order water utilities to test for six nitrosamines and submit the results to a central database from 2005.
Meanwhile, the governments of Ontario and California have both moved towards establishing legal limits for nitrosamines in drinking water, with the EPA also accepting that six major nitrosamines may require further regulation in future.
Last summer, the EPA ended years of inaction by finally revoking all safe tolerances for the amount of chlorpyrifos on food, effectively banning its use on US food crops. It followed a similar decision by the European Union in 2020 and ended the 50-year career of the world’s formerly favourite pesticide, which is now bly linked with human developmental disorders and considered toxic to wildlife.
EPA chief Michael S. Regan admitted it was “taking an overdue step to protect public health” in banning chlorpyrifos, but despite initiatives like this, the world still faces an uphill task in combating chemical pollution. In fact, some scientists believe the world is no longer in a “safe operating space” because the production and environmental release of chemicals and plastics are increasing faster than our ability to assess and monitor them.
6. Per- and polyfluoroalkyl substances (PFAS)
The EPA again signalled its willingness to fight chemical pollution when it announced that 2022 would be a year of ‘laser focus’ on neurotoxic per- and polyfluoroalkyl substances (PFAS) - and announced a $10 billion campaign to combat PFAS water contamination.
Dubbed ‘forever chemicals’ as their extremely b carbon-fluorine bond ensures that they never break down, PFAS have been used widely in manufacturing since the 1940s and become ubiquitous in our environment. An Endocrine Society report last year said PFAS are found “in surface water, deep-sea water, drinking water, waste-water treatment plants, leachates from landfills, sediment, groundwater, soil, the atmosphere, dust, as well as biota including wildlife and humans globally.”
Among the clean-up actions announced by the EPA were commitments to undertake nationwide monitoring for PFAS in drinking water and publish improved analytical methods enabling 40 PFAS to be monitored by 2024. The European Chemicals Agency has meanwhile moved to ban all PFAS from firefighting foams over the next 30 years, saying that the risks from the chemicals are ‘currently not adequately controlled’.