Occurrence of neonicotinoids in waste water from the Bucharest treatment plant

Abstract

A sensitive and selective method SPE-LC-MS/MS for the detection of widely used neonicotinoids (nitenpyram, thiamethoxam, clothianidin, acetamiprid, dinotefuran, and imidacloprid) in waste water was developed. The chromatographic method provided good separation of the six most common neonicotinoid compounds, with limits of quantitation in the range of 0.3–0.9 ng l⁻¹. The developed method was validated, obtaining the corresponding results for all parameters. Recoveries after SPE ranged from 72% to 108.2% meanwhile intra-day and inter-day precision (RSD%) was between 4.6 and 7.7 and 5.2 and 11.3%, respectively. The occurrence and removal of these neonicotinoids in the Bucharest WWTP were investigated. The presence of imidacloprid, thiamethoxam, dinotefuran and acetamiprid was observed at ng l⁻¹ in the influent (60.8–80.2 ng l⁻¹, 16.4–23.6 ng l⁻¹, 4.4–6 ng l⁻¹, and 0.97–2.4 ng l⁻¹, respectively) and effluent (average concentrations 53.3 ng l⁻¹, 14.6 ng l⁻¹, 3.7 ng l⁻¹, and 1.95 ng l⁻¹, respectively). Neonicotinoids from influents were removed in low and similar proportions to the effluent. Thus, dinotefuran and acetamiprid were eliminated in the proportion of 23.2% of the waste water evacuated in the emissary, imidacloprid was eliminated with an average yield of 22.4% and thiamethoxam was removed with an average of 20.3%