Dioxins, Furans, and Dioxin-Like Polychlorinated Biphenyls (Update)

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. Over 90% human exposure is 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 bio-magnify as they climb the food chain. Analysis of foods for dioxins is complex; dioxins are a 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. This leads to large variations in the way data is reported and in the quality of data that may be found in the literature. Measurements of dioxins in food can be used to assess dietary exposure and consumer intake, to assess environmental health, and also to monitor time trends and to evaluate the effectiveness of pollution control measures. These activities are all important aspects of risk assessment. Even though concentrations in the environment are generally decreasing, ongoing monitoring is an important tool to identify new contamination incidents and for food control. While dioxins in the environment and in food are generally recognized as declining in concentration, some related emerging contaminants such as brominated dioxins may be on the increase.