Climate change and urbanization are expected to threaten groundwater quality around the world, according to a new study from UNSW.
Dissolved organic carbon (DOC) is a naturally occurring component of groundwater. However, a high concentration of DOC makes the treatment groundwater more difficult and expensive. This can create challenges in countries like Australia where groundwater is widely used as the main source of drinking water for many cities and towns.
“We identified groundwater DOC concentration increases of up to 45 per cent, largely because of increased temperatures in the wettest quarter of the year—for example, in a number of south-eastern states in the United States,” said Dr. Liza McDonough, a research associate at UNSW and lead author of the study. “We predict increases in DOC in these locations could increase water costs for a family of four by US$134 per year.”
“Other areas such as eastern China, India, and parts of Africa already experience severe groundwater contamination issues,” McDonough added. “These may be further compounded, particularly in south-eastern China, by groundwater DOC increases associated with large predicted increases in temperature in the wettest quarter of the year by 2050.”
The research, published in Nature Communications, examined the largest global dataset that includes 9,404 published and unpublished groundwater DOC concentrations from aquifers in 32 countries across six continents.
“Our next step is to investigate how the character of DOC changes when you have different aquifer minerals, because some types of organic matter can stick to certain mineral surfaces and ultimately reduce this type of organic matter remaining in the water,” said McDonough. “This will help provide guidance on the most suitable water treatment options in areas where DOC concentrations are expected to increase.”