dioxinrelated

Dioxin-related refers to substances, exposures, and health or environmental effects associated with dioxins and related compounds. The term covers polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), as well as dioxin-like polychlorinated biphenyls (PCBs) that exhibit similar toxicity. Dioxins are persistent, lipophilic pollutants with many congeners differing in potency and persistence.

TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin, is the prototype dioxin and among the most toxic. Dioxins exert effects primarily through activation of the aryl hydrocarbon receptor (AhR). Health endpoints include chloracne, immune and endocrine disruption, developmental effects, liver toxicity, and cancer risk, with IARC classifying TCDD as a human carcinogen.

Dioxins persist in the environment for years to decades, bioaccumulate in food chains, and concentrate in animal fats. Human exposure is mainly dietary, through fatty foods such as meat, dairy, and fish. Major sources of releases include industrial combustion, waste incineration, metal production, and chlorine bleaching, though emissions have been reduced in many regions through regulation.

To assess mixed dioxin-like toxicity, risk assessments use toxic equivalency (TEQ) with toxic equivalency factors (TEFs) relative to TCDD. Agencies such as WHO, EPA, and EFSA apply TEQ to inform exposure limits and regulatory actions. Internationally, the Stockholm Convention targets elimination or reduction of releases of dioxins and related compounds, supported by monitoring to protect public health and ecosystems.

Historical incidents, such as the Seveso disaster of 1976, highlighted acute exposure risks. Remediation emphasizes soil removal, high-temperature destruction, and best available techniques to minimize releases. Ongoing research addresses low-level chronic exposure, cumulative risk, and improvements in monitoring, prevention, and risk communication.