Environmental Contaminants: Dioxins, Furans, and Dioxin-like Polychlorinated Biphenyls

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls (PCDD/Fs and dl-PCBs, ‘dioxins’) are ubiquitous environmental contaminants with half lives, both in the environment and in the human body, that are measured in decades. More than 90% human exposure is estimated to be from the diet for most individuals. Exposure levels in most countries are generally falling over time as control measures that have been implemented take effect. However, there are also sporadic episodes than can cause levels to spike in some dietary items. Many of these incidents that lead to increased exposure through the diet result from contaminated animal feed and the fact that these compounds biomagnify as they climb the food chain. Analysis of foods for dioxins is complex; dioxins are mixture of a large number of related compounds that concentrate in fats within a food type, and because of their high toxicity, extremely low limits of determination are required.