RESUMEN
Atmospheric micro-/nanominerals play an important role in the adsorption, enrichment, and migration of organochlorine pesticides (OCPs). In the present study, the correlations between OCPs and minerals in outdoor atmospheric dustfall were investigated, and the correlations were used to speculate the source of p,p'-(dicofol+dichlorobenzophenone [DBP]), which is the sum of p,p'-dicofol and p,p'-DBP. Atmospheric dustfall samples were collected from 53 sites in the Chengdu-Deyang-Mianyang economic region in the Sichuan basin. In this region, 24 OCPs were analyzed by gas chromatography-tandem mass spectrometry. The average concentration of 24 OCPs was 51.2 ± 27.4 ng/g. The results showed that the concentration of Σ24 OCPs in urban areas was higher than that in suburban areas (p < 0.05). Minerals in atmospheric dustfall were semiquantitatively analyzed by X-ray diffraction. The primary minerals were quartz, calcite, and gypsum. A Spearman correlation analysis of OCPs and minerals showed that low-volatility OCPs could be adsorbed by minerals in atmospheric dustfall. A density functional theory simulation verified that p,p'-(dicofol+DBP) in atmospheric dustfall was primarily derived from the p,p'-dicofol adsorbed by gypsum. Isomeric ratio results suggested that the samples had weathered lindane and chlordane profiles and confirmed that residents in the Sichuan basin used technical dichlorodiphenyltrichloroethane. Finally, the OCPs were evaluated to determine the potential risk of cancer in adults and children from OCP exposure. Exposure to OCPs via atmospheric dustfall was safe for adults. The cancer risk for children exposed to OCPs was slightly lower than the threshold value (10-6 ) under a high dust ingestion rate, which poses a concern. Environ Toxicol Chem 2023;42:594-604. © 2022 SETAC.
Asunto(s)
Hidrocarburos Clorados , Plaguicidas , Niño , Humanos , Adsorción , Sulfato de Calcio/análisis , Dicofol/análisis , Cromatografía de Gases y Espectrometría de Masas , Plaguicidas/análisis , Hidrocarburos Clorados/análisis , DDT/análisis , Medición de Riesgo , China , Monitoreo del Ambiente/métodosRESUMEN
Atmospheric drift is considered a major loss path of pesticide from target areas, but there is still a large gap of knowledge regarding this complex phenomenon. Pesticide drift may occur during application (Primary drift) and after it (Secondary drift). The present study focuses on primary and secondary drift from ground applications in peach orchard (tree height of 3 m), under Mediterranean climate. Detailed and prolonged vertical drift profiles at close proximity to orchard are presented, together with detailed measurements of key meteorological parameters. The effect of volatility on drift was also studied by simultaneously applying two pesticides that differ in their volatility. Drifting airborne pesticides were detected both during and after applications at sampling distances of 7 and 20 m away from orchard edge. Concentrations ranged between hundreds ng m-3 to a few µg m-3 and showed clear decrease with time and with upwind conditions. Almost no decline in concentrations with height was observed up to thrice canopy height (i.e., 10 m). These homogeneous profiles indicate strong mixing near orchard and are in line with the unstable atmospheric conditions that prevailed during measurements. While air concentrations during pesticide application were higher than after it, overall pesticide load drifted from the orchard during primary and secondary drift are comparable. To the best of our knowledge this is the first work to show such large vertical dispersion and long duration of secondary drift following ground application in orchards. The obtained information indicates that secondary drift should not be neglected in exposure and environmental impact estimations.