Dead Hedgehogs Unveil Persistent PCB Pollution Decades After Ban

What can examining deceased hedgehogs reveal about environmental conditions? It appears quite a bit, with Swedish scientists discovering "unexpected" outcomes from their investigations.

Researchers at Lund University analyzed specimens taken from dead animals found in southern Sweden and identified alarmingly elevated concentrations of environmental contaminants. Known as 'urban hedgehogs,' these creatures coexist with people, sparking worries over the condition of our living spaces.

Erinaceus europaeus, the European hedgehog is regarded as an 'indicator species' that can signal potential dangers threatening human health at an earlier stage. In their research, scientists discovered a mix of harmful substances in the hedgehogs, such as lead, pesticides, and brominated flame retardants. plastic additives and more.

Notably highlighted was the discovery of polychlorinated biphenyls PCBs were detected in all animals examined in the study, indicating that even after their ban several decades ago, PCBs remain a significant issue for both human and environmental well-being.

How do hedgehogs serve as effective indicators of environmental contamination?

The unassuming hedgehog scours through leaves and plants during the day, searching for insects as food. Their preferences include slugs, snails, and earthworms, though they'll consume eggs, small animals, and carcasses when available.

This way of life makes hedgehogs vulnerable to accumulating chemicals and pollutants. When these long-lasting contaminants travel through the food web, their concentration increases, a phenomenon called biomagnification. In the course of time, as hedgehogs consume numerous tainted prey items, they build up heavy metals, pesticides And plastics accumulate within their bodies.

"Hedgehogs are particularly well-suited for assessing environmental pollution due to their habits," explains Maria Hansson, a professor of ecotoxicology at Lund University and the writer of the report.

They inhabit low-lying areas, consume insects found on the ground, and cover large distances nightly for feeding. Additionally, they drink from storm drains, where water may be contaminated with heavy metals and various pollutants. chemicals , leading to significant exposure to pollutants in urban settings."

Which chemicals were detected in the hedgehogs?

Scientists studied the spines, teeth, and liver tissues from the deceased hedgehogs to assess their exposure to environmental contaminants. The findings indicated that these hedgehogs exhibited elevated levels of lead, along with multiple organic environmental substances.

These chemicals included phthalates, which are used as plasticisers in rubber and plastics, and polychlorinated biphenyls , or polychlorinated biphenyls (PCBs). These are harmful chemicals that have long been prohibited in manufacturing. In the study of hedgehogs, PCBs turned out to be the predominant contaminant, detected in all the animals examined.

PCBs found extensive use across various industries from the 1930s up until they were banned throughout Europe during the mid-1980s. However, these chemicals remain as highly persistent , indicating they can persist in soil, water, and even the air for many decades.

As stated by the European Commission, PCBs are currently categorized as "substances likely to cause cancer in humans" and can lead to numerous harmful impacts on both people and animals. These substances disrupt hormone balances, hinder thyroid activity, modify reproductive functions, and weaken immune responses. Additionally, they have been associated with several issues related to brain development and nervous system functioning. particularly in children and young animals.

Although we've cleaned up the environment, numerous chemicals persist in the soil and near our residences," states Hansson. "Substances such as PCBs form stable compounds that do not decompose and can linger in the soil for decades, possibly even longer.

And now, we're introducing new compounds into the environment such as plastics, which release various chemicals including phthalates—substances known for their ability to interfere with hormones," she explains further. "Additionally, we utilize construction materials and pesticides, and these eventually accumulate within the living beings around us.

These chemicals have been strictly limited in Europe since 1985. According to the Stockholm Convention, industries and governmental bodies dealing with PCBs are required to identify, label, and eliminate them. PCBs By the conclusion of 2025, from components such as transformers and capacitors.

Can these contaminants pose risks to hedgehogs?

The impact of these environmental contaminants on hedgehogs remains unclear to scientists. Nonetheless, since numerous such compounds have been identified as endocrine disruptors, cancer-causing agents, or reproductive interference culprits, experts express concern about their presence in mammals like humans and hedgehogs alike.

Since 2020, hedgehogs have been classified as Near Threatened on the International Union for Conservation of Nature’s Red List. red list . Throughout Europe, their populations have decreased by at least 30 percent within the last ten years, primarily because of habitat destruction and a reduction in available food. However, could environmental contaminants also be affecting their numbers?

I think that this buildup of foreign chemicals in hedgehogs might be one of the reasons behind their population decrease," explains Dr Sophie Lund Rasmussen from Oxford University, who is often called 'Dr Hedgehog'. "Nevertheless, we require additional funding for studies to accurately determine how these substances impact hedgehog health.

Dr. Rasmussen's research on hedgehog contamination revealed that nine out of every ten examined hedgehogs had levels of harmful substances. pesticides . Earlier research has similarly emphasized elevated concentrations of metals, notably lead discovered in hedgehog teeth and livers.

I firmly believe that environmental contamination plays a role in the decrease of hedgehog populations," states Hansson. "Elevated lead concentrations might disorient them, leading to an increased frequency of being hit by vehicles due to abnormal behavior. Additionally, organic pollutants could impact the growth and general reproductive capabilities of their young.

The concerning discovery from the research revealed that PCB accumulation might have a stronger impact on younger hedgehogs. The study indicated that juveniles had elevated PCB levels compared to adult hedgehogs, a pattern also noted in various other animals such as bears, porpoises, and seals.

Hedgehogs stockpile large quantities of fat for both hibernation and nurturing their offspring," says Hansson. "Toxins such as PCBs tend to be stored preferentially in fatty tissues and build up over time, but once this fat reserve is depleted—such as during lactation—the toxins get released back into the body, potentially leading to serious health problems.