Environmental Impact of DEET: Monitoring in Aquatic Ecosystems and Ecotoxicity Assessment

Pollution of surface watercourses and reservoirs with pesticides is a serious global problem. <i>N</i>,<i>N</i>-Diethyl-<i>meta</i>-toluamide (DEET), a widely used repellent against mosquitoes and ticks, can enter aquatic ecosystems from point sources when used outdoors but especially from wastewater from laundry and personal hygiene. This research was focused on the monitoring of DEET in surface water, sediments, plants growing on the banks, gray water and in a wastewater treatment plant (WWTP), both in water and sewage sludge. For identification and quantification of DEET, liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) was used. The study was complemented by determining DEET ecotoxicity to nontarget organisms (<i>Vibrio fischeri</i>, <i>Sinapis alba</i>, and <i>Eisenia andrei</i>). The research has demonstrated the presence of DEET in all investigated areas in water in a concentration range of up to 32.18 μg L^-1. While the concentrations of DEET found do not possess acute toxic effects, it is imperative to acknowledge its potential for chronic effects, toxicity of any possible degradation products, and synergistic effects with other pollutants present in the environment, especially in the aquatic ecosystem.