Dioksiinit

Dioksiinit (dioxins) refer to a broad group of chemically related compounds that include chlorinated dibenzo-p-dioxins (PCDDs) and chlorinated dibenzofurans (PCDFs). The most toxic congener is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Because individual congeners vary in toxicity, risk is commonly expressed as a single index, TEQ (toxic equivalency), based on relative potencies to activate the aryl hydrocarbon receptor (AhR).

They are mainly unintentional byproducts formed during combustion and certain industrial processes, including municipal and medical waste incineration, chlorine bleaching of pulp, and the production of various pesticides and solvents. They also occur in trace amounts from natural events such as volcanic eruptions and forest fires. Dioxins are highly persistent in the environment, bioaccumulate in the food chain, and tend to concentrate in fatty tissues of animals.

Health effects associated with exposure include an elevated cancer risk in humans, as well as potential effects on fetal and child development, reproductive function, immune response, and endocrine systems. The overall risk depends on the level and duration of exposure, the specific congener profile, and the matrix in which exposure occurs (for example, dietary fats).

Regulation and mitigation efforts focus on reducing emissions and environmental release. International frameworks such as the Stockholm Convention aim to eliminate or minimize releases of dioxins and related compounds. In practice, emissions are controlled through high-temperature processes with adequate residence time and destruction efficiency, advanced filtration and scrubbing, and efforts to minimize chlorine-related precursors. Monitoring relies on sensitive laboratory analysis, typically GC-MS, with results expressed in TEQ units.