<b>Determination of Drift of Neonicotinoid Insecticide Thiacloprid Caused by Aerial Spraying </b><b>by Liquid Chromatography-tandem Mass Spectrometry </b>

Abstract

Summar yAn aerial application of neonicotinoid insecticide, thiacloprid, by a manned helicopter for controlling insect (Monochamus altermatus Hope) damage was carried out on pinewoods of Chikuma-city in Nagano Prefecture in June 2013. An investigation on thiacloprid drifts was conducted because many people reside near the applied area. Drifts in the air and in fallouts were collected at 4 locations near the applied area for three days after aerial spraying; and thiacloprid was quantified by liquid chromatography/tandem mass spectrometry. The result is that thiacloprid in the air was found from 4 locations at the maximum concentration of 1.9 ng/m 3 per day. Thiacloprid in fallouts was quantitatively detected from 3 locations at the maximum amount of 7900 ng/m 2 over three days. The maximum drift ratio was calculated to be 0.066 %. The results confirmed that a low-level drift occurred after the aerial application by a manned helicopter. The results suggest that the combination of air concentration measurements and fallout monitoring improved the evaluation of residential exposure to neonicotinoid insecticide.

Exposures of children to neonicotinoids in pine wilt disease control areas

“…Their determination of thiacloprid concentrations in atmospheric particulate matter showed increased thiacloprid concentrations from below LOQ (<35 pg/m 3 ) to 1900 pg/m 3 immediately after spraying exercises and restoration of baseline thiacloprid levels below the LOQ after only 1 d. These observations confirm that thiacloprid has a short atmospheric residence time, presumably because of its low vapor pressure (Supplemental Data, Table S2). The disparity between the trends of atmospheric thiacloprid concentrations observed in the report by Takenouchi and Aoi (2016) and that of the present study may be attributable to differences in sampling spots. Whereas Takenouchi and Aoi (2016) collected atmospheric particulate matter beside the sprayed spots, samples in the present study were collected in the residential area a few kilometers from the sprayed spots.…”

“…The disparity between the trends of atmospheric thiacloprid concentrations observed in the report by Takenouchi and Aoi (2016) and that of the present study may be attributable to differences in sampling spots. Whereas Takenouchi and Aoi () collected atmospheric particulate matter beside the sprayed spots, samples in the present study were collected in the residential area a few kilometers from the sprayed spots. Apparently, a greater proportion of the thiacloprid concentrations in the atmosphere might have either drifted away or settled on the ground at the time of sampling for the present study.…”

“…Particulate matter from study and reference areas were prepared as described (Takenouchi and Aoi 2016). Briefly, shredded filters were put into 10-mL aliquots of ethyl acetate: acetone (9:1, v/v) solutions and sonicated for 5 min.…”

“…Hence, the elevated levels of thiacloprid observed in June likely follow variations in atmospheric thiacloprid concentrations. Similarly, Takenouchi and Aoi (2016) collected air samples during a similar spraying period at the Togura region in Chikuma City of Nagano Prefecture in 2013. Their determination of thiacloprid concentrations in atmospheric particulate matter showed increased thiacloprid concentrations from below LOQ (<35 pg/m 3 ) to 1900 pg/m 3 immediately after spraying exercises and restoration of baseline thiacloprid levels below the LOQ after only 1 d. These observations confirm that thiacloprid has a short atmospheric residence time, presumably because of its low vapor pressure (Supplemental Data, Table S2).…”