More than half of the world’s population faces a looming threat to the quality and availability of their drinking water because climate change and urbanization are expected to cause an increase in groundwater organic carbon, a new University of New South Wales study has found.
The research examined the largest global dataset of 9404 published and unpublished groundwater dissolved organic carbon (DOC) concentrations from aquifers in 32 countries across six continents.
DOC is a naturally occurring component of groundwater, but the higher its concentration, the more difficult and expensive it is to make groundwater drinkable. In Australia, groundwater is widely used as the main source of drinking water for many cities and towns.
Lead author Liza McDonough, Ph.D., of the Connected Waters Initiative Research Centre at UNSW, said the study forecasted elevated DOC concentrations because of projected changes in temperature and rainfall due to climate change, as well as increased urbanization.
“We identified groundwater DOC concentration increases of up to 45 percent, largely because of increased temperatures in the wettest quarter of the year, for example, in a number of southeastern states in the United States. We predict increases in DOC in these locations could increase water costs for a family of four by $134 per year,” McDonough said.
“Other areas such as eastern China, India, and parts of Africa already experience severe groundwater contamination issues. These may be further compounded, particularly in southeastern China, by groundwater DOC increases associated with large predicted increases in temperature in the wettest quarter of the year by 2050.
“Generally, we expect urbanization to increase groundwater DOC concentrations by up to 19 percent, compared to agricultural or natural land use, likely as the result of contamination, for example, through leaking septic and sewer systems.”
The research, a collaboration between UNSW, the Australian Nuclear Science and Technology Organization, Southern Cross University, British Geological Survey, and the University of Bradford, found four major contributing factors to groundwater DOC levels: climate, land use, inorganic chemistry, and aquifer age.
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