PCDDDFs

PCDDDFs refers to the combined group of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, a family of related chlorinated organic compounds that are persistent environmental pollutants. They are produced unintentionally during high-temperature combustion and certain industrial processes, and a wide range of congeners exist. Because they are lipophilic and persistent, PCDDDFs can accumulate in the food chain and remain in the environment for long periods. Toxicity is assessed using toxic equivalency factors (TEFs) that express the mixture as a single toxic equivalent (TEQ).

Common sources include waste incineration, metal smelting, combustion of chlorine-containing materials, and some chlorine-bleaching processes in pulp and paper production. Natural events such as forest fires can also form PCDDDFs. Once released, they can undergo long-range transport and deposit onto soils, sediments, and aquatic systems, where they persist for decades. Human exposure is mainly dietary, especially through animal fats and dairy products, with smaller contributions from air, water, and brief occupational exposure.

Health effects associated with PCDDDFs include carcinogenicity in humans, as well as developmental, reproductive, immune, and endocrine-disrupting outcomes in animals and some human studies. The risk assessment typically uses TEQ values to compare exposures across different congeners and sources.

Regulation focuses on limiting emissions from industrial sources and waste management facilities. Internationally, PCDDDFs are regulated under the Stockholm Convention on Persistent Organic Pollutants, with national programs adopting emission controls, monitoring, and remediation practices. Analytical measurements typically involve sampling followed by gas chromatography–mass spectrometry to determine TEQ concentrations.