Dioxins and PCBs
dioxins, polychlorinated biphenyls, PCBs, furans, dioxinas, bifenilos policlorados
What it is
Dioxins and dioxin-like PCBs are persistent environmental contaminants, not food ingredients. They build up in animal fat and therefore reach people mainly through foods such as fish, meat, dairy products and eggs.
Why BOTIA flags it
Dioxins and dioxin-like PCBs are among the most toxic persistent contaminants that reach food; TCDD, the most toxic dioxin, is classified by IARC as carcinogenic to humans (Group 1), and long-term exposure is linked to effects on the immune system, thyroid hormones and development. They dissolve in fat and can take 7–11 years for the amount in the body to fall by half, so fatty fish, meat, dairy products and eggs are important sources and what matters is the body burden built up over time. They cross the placenta, and breast milk is one of the routes by which the body excretes them — which also transfers part of the mother's stored burden to the infant. JECFA therefore expresses its tolerable intake as a monthly total, not as a limit for one meal.
BOTIA CAN
- Explain which foods are common dietary sources and why the accumulated body burden over time matters more than one meal.
- Explain why the Woman layer matters: dioxins and dioxin-like PCBs cross the placenta and can be transferred to an infant through breast milk.
BOTIA CANNOT
- Detect dioxin or PCB contamination from an ingredient list or determine how much is present in a particular food.
- Calculate a person's toxic-equivalent body burden or determine from one label how much reached a fetus or breastfed infant.