Distribution and accumulation of hexachlorobutadiene in soils and terrestrial organisms from an agricultural area, East China

• Hexachlorobutadiene was analyzed in agricultural soils and terrestrial organisms.
• The levels of HCBD residues were lower than those of organochlorine pesticide.
• HCBD is relatively strongly bioaccumulated by rice and vegetables.
• Hexachlorobutadiene does not biomagnify in Chinese toad terrestrial food chains.

Hexachlorobutadiene (HCBD) is a potential persistent organic pollutant that has been found in abiotic environments and organisms. However, information on HCBD in soils and its accumulation in terrestrial food chains is scarce. This study investigated the accumulation of HCBD in soils, plants, and terrestrial fauna in a typical agricultural area in Eastern China, and drew comparisons with organochlorine pesticides (OCPs). The HCBD concentrations in soils were <0.02–3.1 ng/g dry weight, which were similar to α-endosulfan concentrations but much lower than the concentrations of some other OCPs. The HCBD soil–plant accumulation factors, 8.5–38.1, were similar to those of o,p′-DDT and higher than those of HCHs and p,p′-DDT, indicating that HCBD is strongly bioaccumulated by rice and vegetables. HCBD concentrations of 1.3–8.2 ng/g lipid weight were found in herbivorous insects, earthworms, and Chinese toads. The biomagnification factor, the ratio between the lipid-normalized concentrations in the predator and the prey, was found to be 0.16–0.64 for different food chains of Chinese toads, so HCBD was found not to biomagnify, which is in contrast with OCPs. Further research into whether HCBD is biomagnified in high trophic level organisms or through the entire terrestrial food web is required.