1 research outputs found
Mass Balance Assessment for Six Neonicotinoid Insecticides During Conventional Wastewater and Wetland Treatment: Nationwide Reconnaissance in United States Wastewater
Occurrence
and removal of six high-production high-volume neonicotinoids
was investigated in 13 conventional wastewater treatment plants (WWTPs)
and one engineered wetland. Flow-weighted daily composites were analyzed
by isotope dilution liquid chromatography tandem mass spectrometry,
revealing the occurrence of imidacloprid, acetamiprid, and clothianidin
at ng/L concentrations in WWTP influent (60.5 ± 40.0; 2.9 ±
1.9; 149.7 ± 289.5, respectively) and effluent (58.5 ± 29.1;
2.3 ± 1.4; 70.2 ± 121.8, respectively). A mass balance showed
insignificant removal of imidacloprid (<i>p</i> = 0.09,
CI = 95%) and limited removal of the sum of acetamiprid and its degradate,
acetamiprid-<i>N</i>-desmethyl (18 ± 4%, <i>p</i> = 0.01, CI = 95%). Clothianidin was found only intermittently, whereas
thiamethoxam, thiacloprid, and dinotefuran were never detected. In
the wetland, no removal of imidacloprid or acetamiprid was observed.
Extrapolation of data from 13 WWTPs to the nation as a whole suggests
annual discharges on the order of 1000–3400 kg/y of imidacloprid
contained in treated effluent to surface waters nationwide. This first
mass balance and first United States nationwide wastewater reconnaissance
identified imidacloprid, acetamiprid, and clothianidin as recalcitrant
sewage constituents that persist through wastewater treatment to enter
water bodies at significant loadings, potentially harmful to sensitive
aquatic invertebrates