Hexachloronaphthalene

Hexachloronaphthalene (HCN; CAS 1335-87-1) has been used along with other chlorinated naphthalene congeners in commercial mixtures since the beginning of the twentieth century. Over time, levels of HCN in the environment, wildlife, and humans exceeded levels present in the commercial mixture, indicating persistence and bioaccumulation of the specific HCN congener. Toxicity data for HCN are limited, but based on HCN's structural similarity to dioxin and dioxin-like activity, HCN has raised global concern over other chlorinated naphthalenes. This section discusses the toxicity of HCN, but where data are limited on this specific congener, general toxicity of polychlorinated naphthalenes (PCNs) is discussed, as many studies performed with PCN mixtures include HCN. At high doses mortality, liver damage, and degeneration of kidneys in rats, rabbits, and cattle were reported. Poisoning in humans includes anorexia/weight loss, nausea, restlessness, drowsiness, confusion, fatigue, fever, anemia, skin problems, eye irritation, headache, vomiting, vertigo, and severe abdominal pain. Reproductive and developmental toxic effects are reported. Due to their persistence, bioaccumulation, and toxicity profiles, chlorinated naphthalenes (including HCN) have been nominated for inclusion as persistent organic pollutants under the United Nations Environmental Programme (UNEP) Stockholm Convention on Persistent Organic Pollutants.