Hexachloropentadiene in Soil, Air, and Biota Around an Agrochemical Factory: Concentrations, Distribution, and Risk Evaluation

Hexachloropentadiene (HCPD) is a highly toxic compound that is mainly used for preparation of organochlorine insecticides. To investigate HCPD contamination of the environment during pesticide processing, 153 air, soil, and biota samples were collected around an agrochemical factory in different seasons of 1 year and analyzed for HCPD. The HCPD concentrations were 0.01–12.7 ng/m 3 (average 2.60 ng/m 3 ) in the air samples and 0.14–51.5 ng/g (average 4.11 ng/g) in the soil samples. HCPD concentrations were highest within 1 km north of the production site, which was in the downwind direction of the factory and storage tanks, especially in autumn and winter. Soil–air exchange analysis showed that HCPD was deposited from air to soil with a flux of 0.003 to 0.20 ng/(m 2 d) throughout the year. The dismantling of obsolete equipment accelerated the release of HCPD into the air and increased the amount of HCPD deposited in the soil. HPCD concentration ranges were 0.44–55.7 ng/g dry weight [d.w.] (average 22.2 ng/g d.w.) and 6.69–91.4 ng/g d.w. (average 26.2) in locally grown rice and wheat, respectively. The concentration range was 12.1–1596 ng/g lipid weight (average 560 ng/g lipid weight) in local organisms, except for chicken. In tissues from locally raised chicken, the HCPD concentrations decreased in the order of gizzard, liver, heart, and meat. HCPD was amplified through a short food chain (soil, Vigna unguiculata leaves, larvae of Pieris rapae , and chicken), and the bioaccumulation factor gradually increased over a range of 1.19–25.1 (mean 9.81).