The European Food Safety Authority (EFSA) has updated its risk assessment for dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) in food and feed, concluding that current dietary exposure levels in Europe remain a concern the use of revised toxicity calculations.

The assessment reevaluated the health risks associated with dioxins and DL-PCBs using updated toxic equivalency factors (TEFs) issued by the World Health Organization (WHO) in 2022. The European Commission had requested EFSA conduct the updated risk assessment to determine whether the revised TEFs affected EFSA’s 2018 conclusions on the human health risks of dioxins and DL-PCBs.

What are Dioxins and DL-PCBs?

Dioxins are environmental contaminants generated as byproducts of certain industrial processes and waste incineration. DL-PCBs originate from PCB-containing oils that were historically used in industrial applications. Although regulatory controls have substantially reduced environmental emissions, the compounds persist in the environment and continue to accumulate in fatty foods such as meat, fish, eggs, and dairy products.

Health Harms of Dioxins and DL-PCBs

EFSA’s updated assessment confirmed previous findings linking developmental exposure to dioxins and DL-PCBs with adverse reproductive effects, including reduced sperm production and lower sperm concentrations later in life. The agency said exposure before birth and during early childhood remains a key concern.

New Tolerable Weekly Intake

Using the 2022 WHO TEFs, EFSA established a new tolerable weekly intake (TWI) of 0.6 picograms toxic equivalents (pg TEQ) per kilogram of body weight (kg BW) per week. The updated TWI is based on evidence from animal and human studies and incorporates an uncertainty factor to account for differences in how humans process and accumulate these compounds. 

The previous TWI established in 2018 is 2 pg TEQ/kg BW.

Europeans’ Exposure to Dioxins Still Too High

Application of the revised WHO TEFs reduced estimated dietary exposure to dioxins and DL-PCBs by approximately 27–35 percent compared with exposure estimates calculated using the previous 2005 TEFs. However, EFSA determined that average dietary exposure across all European age groups still exceeds the new TWI.

Data on dioxin and DL-PCB concentrations in human milk also supported the conclusion that exposure remains above levels considered tolerable.

The agency reported 95 percent certainty that the TWI is equal to or greater than 0.6 pg TEQ/kg body weight per week and 99–100 percent certainty that average adult exposure exceeds the TWI.

According to EFSA, the findings suggest that current exposure levels among women of childbearing age may still pose a risk to the reproductive health of future male offspring.

Future Research Needs

To reduce uncertainty in future assessments, EFSA recommended additional research on human-relevant TEFs, expanded biomonitoring of dioxins and DL-PCBs in human milk and blood, improved toxicokinetic models, enhanced analytical methods, and further investigation into contamination pathways in food-producing animals.

The updated opinion also called for additional research into the effects of dioxins and DL-PCBs on sperm production and the contribution of plant-based foods and soil ingestion by livestock to overall dietary exposure.

Relatedly, EFSA is now carrying out a risk–benefit assessment of fish consumption, looking at nutritional benefits alongside potential adverse effects due to exposure to several contaminants, including dioxins and dioxin-like PCBs. This work is expected to finish by the end of 2027 and was requested by the European Commission to support national authorities in providing dietary advice to their citizens.