Seasonal Variation and Exposure Risks of Perchlorate in Soil, Indoor Dust, and Outdoor Dust in China

Abstract

A total of 97 paired soil, outdoor dust, and indoor dust samples were collected in the national scale of China in summer, and the perchlorate levels were compared with those in soil and outdoor dust samples collected in winter in our previous study. The median perchlorate concentrations in the outdoor dust, indoor dust, and soil samples were 8.10, 11.4, and 0.05 mg/kg, respectively, which were significantly lower than those in the winter samples due to the natural factors and human activities. No significant differences in perchlorate concentrations were found between Northern and Southern China in the dust samples, whereas the difference was obtained in the soil samples. In the terms of possible source, the perchlorate levels in the outdoor dust exhibited strong correlation with SO (r = 0.458**) and NO (r = 0.389**), indicating part of perchlorate in outdoor environment was likely from atmospheric oxidative process in summer. The perchlorate, SO, and Cl levels in the indoor dust were significantly related to those in the outdoor dust, suggesting that outdoor contaminants might be an important source for indoor environment. Furthermore, the human exposure to perchlorate was under relatively safe state in China except for special sites or periods with high perchlorate levels. Dust made an unexpected contribution of 41.3% to the total daily perchlorate intake for children, whereas 2.46% for adults in China based on biomonitoring, which deserves more attention.

Occurrence, spatial distribution, and risk assessment of perchlorate in tea from typical regions in China

“…Among them, the high content of perchlorate in central China is closely related to the surrounding environment, such as irrigation water, dust, and soil. Previous studies have also found that perchlorate is ubiquitous in indoor, outdoor, and soil in different regions of China ( Gan et al, 2014 , 2015 ; Li et al, 2018 ), and a relatively higher concentration of perchlorate was observed from fireworks manufacturing areas in China ( Zhang et al, 2015 ). So, there is a certain correlation between the main production areas of fireworks and firecrackers in Hunan and Jiangxi in China and the exposure to perchlorate in these areas ( Li et al, 2014 ).…”