Groundwater, a resource often overlooked, is a global concern due to its declining quantity and quality. Managed aquifer recharge (MAR) is a common method used to protect and ensure stable groundwater systems for drinking water supplies by artificially recharging them with surface water.
This technology, well developed and increasingly utilized worldwide, involves the artificial infiltration of surface water, such as lake or river water, into the subsurface to refill groundwater systems.
While MAR is an efficient way to ensure sufficient water quantity, it may pose risks as the surface waters used often contain elevated concentrations of anthropogenic chemicals of emerging concern (CECs), such as plastics, pesticides, pharmaceuticals and personal care products (PPCPs), or per- and polyfluoroalkyl substances (PFAS).
Tabea Mumberg, a dedicated PhD student at the University of Gothenburg, is at the forefront of unraveling the mysteries of PFAS migration pathways in MAR plants. Her groundbreaking research sheds light on the risks and opportunities associated with this essential water security strategy.
Their new study suggests that the mounting presence of newly identified chemicals in surface water demands urgent attention. With stricter EU guidelines on clean drinking water looming, better monitoring of persistent organic contaminants and redesign of artificial groundwater recharge systems are needed.
PFAS, a group of over 16,000 persistent contaminants, lurk in numerous everyday products, from fire-extinguishing foams to water-repellent textiles. Reintroducing surface water into the subsurface poses a significant risk of contaminating groundwater systems with these harmful chemicals.
In a recently published literature review, Tabea Mumberg delves deep into the transport process of Contaminants of Emerging Concern (CECs) through Managed Aquifer Recharge (MAR) systems, shedding light on the urgency of addressing this critical issue.
“My study highlights the need to use regular monitoring programs that specifically address CECs. This is especially important for the CECs that are not yet regulated,” Tabea Mumberg says. “25 percent of drinking water in Sweden is produced using MAR, so this is a common technique. Little is known about how well today’s MAR technology meets up to new challenges posed by CECs.”
In light of the escalating impact of extreme weather events such as droughts and floods, the water industry is under mounting pressure to guarantee the delivery of high-quality drinking water. Despite stringent EU regulations governing water quality, water suppliers face the challenge of complying with future lower CEC drinking water guidelines, along with the increasing presence of CECs in surface waters.
Furthermore, the study underscores the pressing need for viable treatment options to enhance the retention of chemicals during MAR.
Understanding the behavior of these contaminants in raw water systems is pivotal in minimizing CEC concentrations before embarking on expensive drinking water treatment processes.
Journal reference:
- Tabea Mumberg, Lutz Ahrens, Philipp Wanner. Managed aquifer recharge as a potential pathway of contaminants of emerging concern into groundwater systems – A systematic review. Chemosphere, 2024; DOI: 10.1016/j.chemosphere.2024.143030
