A Review on Hexachloro-1,3-butadiene (HCBD): Sources, Occurrence, Toxicity and Transformation.

Hexachloro-1,3-butadiene (HCBD) is a persistent organic pollutant listed in Annex A and C of the Stockholm Convention. This review summarized the sources, occurrence, toxicity, and transformation of HCBD in the environment. HCBD had no natural sources, and anthropogenic sources made it frequently detected in environmental medium, generally at µg L- 1 and µg kg- 1 in water and soil (or organism) samples, respectively. HCBD posed reproductive, genetic, and potentially carcinogenic toxicity to organisms, threatening human health and the ecosystem. Upon biodegradation, photodegradation and physicochemical degradation processes, HCBD can be degraded to a different extent. Nevertheless, further studies should be focused on the potential emission sources and the impact of HCBD on human health and the environment. Additionally, exploring removal technologies based on advanced oxidation and reduction are recommended.