With the discovery of the toxicity and harmfulness of polychlorinated biphenyls (PCBs) to human health and the environment and the classification of these chemical compounds as persistent organic pollutants (POPs) by the Stockholm Convention in 2004, their production was banned in a large number of countries.
What are polychlorinated biphenyls (PCBs) and how do they affect health and the environment?
July 8, 2024

Molecule of polychlorinated biphenyl (PCB 126).
Exposure to toxic chemicals is often linked to various health issues in humans, as founded by numerous scientific studies. Often we are unaware of exposure to dangerous chemicals while performing routined activities or consuming food, water, etc. PCBs belongs to a group of toxic chemicals, and exposure to these chemical compounds can have negative impacts on health and the environment. Therefor, raising awareness and education about such substances is essential as it can help to protect our health.
What are PCBs?
Before we begin discussing how PCBs affect health and the environment, it is essential to fully understand what PCBs actually are, the characteristics of these chemical compounds, and where they can be found.
Polychlorinated biphenyls, commonly known as PCBs, are synthetic aromatic chemical compounds that do not occur naturally in the environment. Due to their properties, these chemicals belong to the group of persistent organic pollutants (POPs)—a category of toxic substances that remain stable in the environment, have a tendency to bioaccumulate, and present significant risks to human health and the environment. This group of chemicals is often referred to as "enternal chemicals" because of their remarkable ability to remain unchanged for exceptionally long periods.
The use of PCBs was most widespread in the mid-20th century. Due to their non-flammability, chemical stability, and electrical insulation properties, these chemical compounds were primarily used for cooling and insulation effects in industrial and consumer products, most commonly in transformers, capacitors, electronic equipment, motor oils, and various insulators.

The discovery of the toxicity and harmful effects of polychlorinated biphenyls (PCBs) on human health and the environment, along with their classification as persistent organic pollutants (POPs) under the Stockholm Convention in 2004, led to the prohibition of PCB production in many countries. Despite the global ban on PCB production for an extended period, their negative impact on human health remains significant.
Even though production has ceased, substantial amounts of PCBs are still in use due to the long lifespan of these chemical compounds. According to the inventory of POPs stockpiles in Bosnia and Herzegovina, it has been determined that 301 tons of equipment containing PCBs are still in use, while 30 tons of PCB-containing equipment have been taken out of service.
How do PCBs affect human health?
Exposure to PCBs can have extremely negative consequences to human health. Health conditions most commonly associated with PCB exposure include cancers, acute illnesses, heart diseases, asthma, cognitive impairments, skin disorders, weakened immune systems, and more.
However, the question is how does exposure to these chemical compounds occur?
PCBs are released into the environment through accidental or intentional discharges of these chemicals. Poorly maintained waste disposal sites, improper, inadequate, and illegal disposal of PCB-containing waste, leaks from electrical transformers containing PCBs, and the incineration of certain waste in municipal and industrial facilities all contribute to the release of these toxic compounds into the environment even today.

PCB concentrations can be found in water, air, soil, snow, and rainwater, allowing them to enter the food chain and significantly bioaccumulate.
Humans can ingest PCBs through the consumption of contaminated food, exposure to polluted air, and dermal contact. The negative health effects are not immediate but may occur due to their accumulation in the body and depend on the amount of PCB ingested.
In BiH several studies have been done related to presence of PCB in eggs, certain seafood, and rivers. The World Health Organization (WHO) and the United Nations Environment Programme (UNEP) have conducted global studies on PCB presence in human milk since 1987, but Bosnia and Herzegovina has not been included in these studies.
How do PCBs affect animals and the environment?
The impact of PCBs on animals is very similar to their effects on humans. Through the consumption of contaminated food, these chemical compounds enter animal organisms. As a result of bioaccumulation, PCB concentrations in species at the top of the food chain can be significantly higher than in species at the bottom of the chain.
In the air, PCBs are mostly present in a gaseous phase and are absorbed into particles. Surface waters can become contaminated with PCBs through atmospheric precipitation (rain, snow), direct emissions from sources, or improper waste disposal.

Activities related to PCBs within the POPs project in BiH
Within the framework of the project "Environmentally Sound Management of Persistent Organic Pollutants (POPs)", funded by Sweden and implemented by UNDP in BiH, technical and financial support has been provided so far in the development of relevant regulations, as well as the Remediation and Reclamation Project for two identified PCB hotspots in Bosnia and Herzegovina - the "Incel" Business Zone and the "HAK1" Business Zone. As part of the project activities, a Map of Hotspots in Bosnia and Herzegovina will be developed with financial support from the Federal Ministry of Environment and Tourism.