Indoor contamination from pesticides used for outdoor insect control

The present study assessed the indoor level of pesticide residue contamination at a total of 45 dwelling facilities in 5 cities of South Korea from June to November 2014. Pesticide residue contamination was assessed by measuring the frequency and concentration of chlorpyrifos, dichlorvos, and cypermethrin residues in airborne particles, indoor dust, and surface wipes. A preparatory test showed a decreasing tendency in the concentrations of pesticide residues in indoor air over time: from 0.458 to 0.073mg/m³ in dichlorvos for 4weeks and from below 0.050mg/m³ to non-detection in the other substances for 2weeks. Then, pesticide residues were detected indoors 4weeks after outdoor chemical control, implying the infiltration of pesticide particles from outdoors. Airborne particles of dichlorvos were found at a higher level (74.4% of samples at a concentration of 0.053mg/m³), whereas those of the other substances were detected at lower levels (6.1% at 0.002mg/m³ in chlorpyrifos and 9.4% at 0.022mg/m³ in cypermethrin). There was no consistent tendency in the indoor levels of pesticide residue contamination according to dwelling types or indoor height. The indoor levels of dichlorvos residue contamination were lower in industrial districts than in urban or rural districts: 63.9% and 0.013mg/m³ for airborne particles, 13.3% and 0.002μg/g for indoor dust, and 6.7% and 0.001mg/cm² for surface wipes, respectively. There were no significant differences in the indoor levels of pesticide residue contamination between urban and rural districts. The current study found that most dwelling facilities managed their indoor levels of pesticide residue contamination below permissible exposure limit (PEL, 1.0mg/m³) or threshold limit value (TVL, 0.1mg/m³), whereas some facilities did not. So, we suggest that certain guidelines should be drawn up regarding the indoor environment management.