Common Insect Repellent DEET Accumulating in Global Water Supplies
DEET, a widely used insect repellent, is increasingly detected as a global water contaminant in rivers, lakes, groundwater, and treated drinking water. Scientists warn it's an emerging pollutant, urging better monitoring and management. Its presence, stemming from daily use and incomplete wastewater treatment, poses risks to aquatic ecosystems, affecting algae, fish, and microbial communities. Further research and advanced treatment methods are crucial to mitigate its environmental impact and protect public health.
DEET, a widely utilized insect repellent, is now extensively identified as a growing water contaminant across continents, appearing in surface waters, groundwater, and even treated drinking water. This widespread presence stems from various everyday activities, including personal use, laundry, and agricultural applications, exacerbated by wastewater treatment plants' inability to fully remove the chemical. DEET's high mobility in water columns allows it to travel long distances, with concentrations peaking in areas like tourist coasts, urban zones near effluent discharges, and critically, solid-waste sites, which show the highest contamination levels.Ecological concerns are significant, as DEET adversely affects aquatic life: sensitive algae experience cell injury, fish and invertebrates show growth limitations and disrupted neural activity, and microbial communities vital for nitrogen cycling are altered. Evidence also suggests its potential movement through the food web into mussels, bees, and honey. Importantly, DEET's combination with other common chemicals, such as caffeine, sunscreen ingredients, or pesticides, can intensify cellular damage and lead to genotoxic effects, broadening the scope of ecological risk. While global risk averages are deemed moderate, landfill leachate, groundwater, and surface waters present the highest concerns. Key uncertainties persist due to insufficient long-term monitoring in heavy-use regions, unknown risks for sensitive populations, and unstudied links to microbial adaptation or antibiotic resistance. Researchers advocate for advanced oxidation systems, including ozonation and hybrid UV/chemical filtration, for more effective DEET degradation. They also call for a coordinated global monitoring network, localized ecological data, and further research into long-term exposure effects to inform safer product design and regulations, ensuring both public health and freshwater environmental protection.
