Cancer-causing chemicals found in eggs collected from industrial sites in Africa

Scientists have found high levels of toxic chemical dioxins known to cause cancer in free-range eggs collected from industrial sites in Africa, Asia, Europe as well as North and South America.

Photo credit: File

Leon Lidigu in Stockholm, Sweden

Scientists have found high levels of toxic chemical dioxins known to cause cancer in free-range eggs collected from industrial sites in Africa, Asia, Europe as well as North and South America.

This comes after the researchers found that 88 percent of the egg samples contained dioxins above the European Union (EU) safety limits for dioxins, or for the sum of dioxins and dioxin-like polychlorinated biphenyls (PCBs) and means that unintentionally produced chemicals regulated in developed countries since the 1990s and internationally since 2004 continue to poison the food supply at concentrations that pose serious health threats.  

Free range involves rearing animals and chicken in wide open spaces where they live in nature, eating natural foods and soaking in the sunlight.

Dioxins are a group of highly toxic chemical compounds that are harmful to health and can cause problems with reproduction, development, and the immune system, can disrupt hormones and lead to cancer.

In a new peer reviewed study published in the journal Emerging Contaminants, the experts highlight that in many areas, children consuming just a few eggs a week would exceed the tolerable intake for dioxins established by the European Food Safety Authority (EFSA), often by 10, and in some cases, up to several 100 times.

“The peer-reviewed analysis found the highest dioxin-contaminated eggs near an e-waste site in Agbogbloshie, Ghana. A child eating one egg from this would ingest more dioxins than EFSA considers a “tolerable intake” for five years,” the scientists highlight.

“The study monitored eggs from more than 110 free-range chicken flocks near waste incinerators, metal industries, cement plants, landfills, e-waste sites, chemical plants, and other facilities, and found that 92 per cent  of egg samples collected from areas near incinerators exceeded the EU regulatory food limits;100 percent  of the egg samples collected from areas near industrial metal sites and e-waste recycling facilities exceeded the EU regulatory food limits; 14 percent exceeded the EU food limits by more than 10 times; while one sample from an e-waste site in Ghana contained the highest contamination ever detected, at more than 264 times the EU food limit for dioxins.”

According to the experts who conducted the study from Arnika, a Czech-based NGO and Ipen -- a global environmental and toxic waste network with more than 600 public interest organisations in more than 120 low- and middle-income countries, including Kenya -- burning plastic waste is the main contributor to the creation of dioxins, especially in developing countries where plastic waste from the West is often shipped.

By burning of waste

Dioxins are unintentionally released by certain chemical industries by burning of waste, in metal production and by other industrial processes.

“PCBs are also carcinogenic to humans and 1.3 million tonnes were used over decades in electrical equipment, in buildings, and for industrial applications, resulting in global contamination. PCBs are also formed unintentionally in the same processes as dioxins. Both groups of chemicals were among the original “dirty dozen”

substances banned and/or regulated globally under the Stockholm Convention since 2004,” the peer reviewed study points out.

Dr Jindrich Petrlik, who is the Ipen adviser on dioxins and waste, program director for Arnika and lead author of the study, believes that the toxic legacy of dioxins and PCBs continues to put children and families at risk.

“We urgently need stronger low POPs (persistent organic pollutants) content levels in waste and stronger implementation of the Stockholm Convention to protect our health and the environment from these long-lasting chemical threats.”

Dr Roland Weber, the corresponding author of the study and a consultant to United Nations (UN) agencies for the implementation of the Stockholm Convention, stressed that eggs are often locally produced in developing countries and are an important food source as they are inexpensive and highly nutritious. Eggs are also a major pathway for human exposure to toxic chemicals from soils and are sensitive biomarkers of environmental contamination of soils.  

“These findings reveal that we need a systematic assessment of chicken eggs and other free range livestock around these emission sources and shows the need to reduce human exposures from sites which have been contaminated with POPs and other persistent pollutants,” he said.

In addition to industrial sites, contaminated eggs were found at many sites where plastic was incinerated and the annual amount of dioxins in waste incineration ash exceeds the tolerable intake for dioxins for the entire human population by up to 133 times.

This ash is often disposed of into the environment, with access to chicken and other livestock.

“Ash from incineration or metallurgy is a common source of soil contamination, yet current standards under the Basel Convention for “low limits” of POPs allow extremely high concentrations of dioxins.
“Under the current standard, a single kilogram of ash is allowed to contain dioxin at a level that would make 7,000 kilograms (seven tonnes) of soil unfit for producing eggs from free-range chickens,” experts observed.

Global ‘Plastics Treaty’

This happens even as last week, global ‘Plastics Treaty’ negotiating parties met in Senegal and from June 6, the parties to Stockholm and Basel Conventions began meeting in Geneva and will discuss what they describe as stricter limits for dioxins and dioxin-like PCBs in wastes.  

There is a proposal from a group of 53 African countries to set more reasonably Low POPs Content Levels (LPCLs) for dioxins in waste.
The Stockholm Convention has also set a goal of phasing out all uses of PCBs by 2025 and identifying and disposing of PCBs globally by 2028, though estimates suggest that millions of tonnes of PCB-contaminated oil and equipment have still not been eliminated.  

“The upcoming negotiations in Geneva and the Plastics Treaty present important opportunities for the world to take action for the protection of our health and our planet,” notes Dr Petrlik.

“The LPCLs proposal from the African countries should be adopted and we must develop a Plastics Treaty that promotes innovation for safer materials and provides pathways to urgently eliminate production of plastics that contain toxic chemicals.”

Another recent study stresses that global chemical contamination has transgressed the “planetary boundaries” for pollution and pointed to the global contamination from plastics production and disposal.

The experts recommend strengthening regulatory limits for contaminated soils, fertilizers, and other soil amendments, and soil pollution prevention through improved chemical and waste management and the management of contaminated soils.

They also call for  an overall reduction of plastic use and an environmentally sound management of plastics at the end of life, along with export restrictions on plastic waste and e-waste as required by the Basel Convention, capacity building and support for developing countries that they can assess and control industrial releases and monitor food and human exposures from contaminated areas as well as  improved management of POPs waste and tracking of pollution from the POPs life cycle while also recommending compensation for farmers and affected populations by applying the polluter pays principle.


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