New Study Reveals Alarming Levels of Toxic Chemicals in Free-range Eggs from 5 Continents

A new study by an international team of scientists and civil society experts published this month in the peer-reviewed journal Emerging Contaminants shows that free-range eggs from five continents contain some of the world’s highest levels of highly toxic chemicals, including substances banned globally and others under consideration for global regulations. Brominated flame retardants and brominated dioxins, chemicals found in the eggs, are linked to serious health impacts, including endocrine disruption, reproductive toxicity, neurodevelopmental impairment, damage to the immune system, and cancer. 

“Our results clearly demonstrate that brominated dioxins and flame retardants are a global threat to human health and the environment. The evidence is overwhelming – brominated and mixed brominated-chlorinated dioxins must urgently be listed under the Stockholm Convention, and the use of brominated flame retardants must be phased out, including recycling of waste containing these chemicals,” said lead author Jindrich Petrlik of Arnika and IPEN. The Stockholm Convention POPs Review Committee (POPRC) is meeting in Rome next Monday, September 29 through October 3 and will discuss the global risks from brominated dioxins.  

The study findings reveal that eggs near e-waste sites, dumpsites, and waste incinerators are severely contaminated with brominated dioxins (PBDD/Fs) and brominated flame retardants (BFRs), making them a major source of human exposure to these toxic chemicals. Among the brominated flame retardants found by the study are polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD), chemicals banned globally by the Stockholm Convention. These BFRs are common in plastic e-waste and released when plastic is burned in dumpsites or incinerators, resulting in environmental contamination that can be picked up by free-range chickens and transferred to their eggs. 

“In Thailand, many communities live close to informal e-waste recycling sites,with some locations even combining recycling activities with areas where food is prepared and consumed,” said Thitikorn Boontongmai from Ecological Alert and Recovery–Thailand (EARTH), a co-author of the study. “Our study shows that this practice can expose families to dangerous levels of these toxic chemicals through direct contact, inhalation, and ingestion. Listing these chemicals under the Stockholm Convention is crucial to protect our communities.” 

“In Africa, people often raise chickens in their backyards, sometimes right next to waste dumpsites or incinerators,” said Griffins Ochieng, director of the Centre for Environment Justice and Development (CEJAD) in Kenya and one of the co-authors of the study. “This study shows the urgent need for global action. Regulators in Kenya look to the international environmental agreements for guidance. Using global restrictions under the Stockholm Convention as a model, we can forge national policies to protect our communities.”

Brominated dioxins have similar properties as chlorinated dioxins, which are already regulated globally under the Stockholm Convention. Given the overwhelming scientific evidence of the harms from these chemicals, IPEN and Arnika are calling on the POPRC to recommend listing brominated dioxins under the Stockholm Convention. 

While brominated flame retardants have been largely phased out, industry has more recently replaced BFRs in many products with new, closely related chemicals (called novel BFRs or nBFRs). Studies show that nBFRs often have similar health and environmental consequences. Thus, the new study finding nBFRs in eggs shows that this kind of hazardous (so-called “regrettable”) substitution does not provide safer alternatives. 

Key findings from the study:

• At an e-waste site in Ghana, eggs contained extremely high levels of brominated dioxins (503 pg TEQ/g fat). Compared with regulatory standards for closely related chlorinated dioxins, the eggs from Ghana contain 200 times higher levels than the safety standard for food. 

• The eggs from Ghana also contain high levels of brominated flame retardants (over 1,200 ng/g fat PBDEs). EU food safety authorities have emphasized the need to minimise exposure to BFRs.

• In Kazakhstan, eggs were found with more than 18,000 ng/g fat of HBCDD – among the highest levels ever recorded worldwide.

The study emphasizes that contaminated eggs are not just an environmental signal but also a direct public health concern. Eggs are a cheap and essential source of protein worldwide, and in contaminated areas, frequent consumption can pose serious health risks. The bioassay method used in the study (called DR CALUX®) provides a robust and cost-effective way to detect the total dioxin-like toxicity in food, including mixtures of brominated, chlorinated, and mixed halogenated dioxins.

The review builds on years of research by IPEN and Arnika, with chemical analyses carried out by laboratories at the University of Chemistry and Technology in Prague, BioDetection Systems in Amsterdam, and MAS in Münster, Germany, where free-range eggs from 15 countries were analyzed for brominated dioxins. 

The authors call for:

• listing PBDD/Fs and mixed brominated-chlorinated dioxins (PXDD/Fs) under the Stockholm Convention,
• stronger global controls on brominated flame retardants and their wastes, including the evaluation of novel flame retardants such as BTBPE and DBDPE for potential listing under the Stockholm Convention
• banning exports of e-wastes and plastic wastes to developing countries,
• environmentally sound management of ashes from waste incineration and metallurgical processes,
• prevention of recycling of plastics containing brominated compounds and
• substitution of brominated flame retardants with safer alternatives.