PCBs - a forgotten legacy? | UNEP - UN Environment Programme

What are PCBs?

PCBs, or polychlorinated biphenyls, are a group of POPs, toxic, man-made, hazardous organic chemicals that have dangerous effects on the environment and our health.

PCBs hazardous effects

PCBs persist in the environment for long periods and can travel over great distances through air, water and migratory species across international boundaries. They accumulate in fatty tissues and bio-magnify higher up in the food chain, where they can be harmful to top predators such as tuna, seals, polar bears and humans. Of the 209 different types of PCBs, 13 are considered to be dioxin-like POPs. Their persistence in the environment corresponds to the degree of chlorination, and half-lives can vary from 10 days to one-and-a-half years.

PCBs effects — *Effects of PCBs on the Environment and on Human Health*

It is a global issue, everyone in the world is likely to have PCBs quantities in his or her body. The map shows some examples of this global toxic legacy.

Although no longer allowed to be produced, PCBs can still be found everywhere, they remain a toxic legacy to the environment and to human health.

GMP Interactive dashboard The UNEP/GEF Global Monitoring project measures concentrations of PCBs in air, human milk and samples of national interest. See the results in the interactive dashboard.

PCBs production and uses

PCBs were produced in large quantities between the 1930s and 1980s. They were used in closed applications (such as electric transformers and capacitors) and in open applications (such as paints, sealants, carbon paper, installations and machinery) where they are more easily released into the environment and therefore pose a significant risk from direct human exposure in daily life. PCBs are also formed and released unintentionally from several anthropogenic sources such as, waste incinerators, cement kilns, metallurgical industry, residential combustion, among others. Plastics may contain PCBs.

It is estimated that between 1 and 1.5 million tonnes of PCBs (UNEP/POPS/COP.9/INF/10) have been produced worldwide by a small number of countries (12) since the late 1920s.

Global estimate of PCB Production — *Estimates of global PCB production (tons) as "pure" chemical (UNEP-POPS-COP.8-INF-10)*

It is important to note that due to dilution and cross-contamination, the mass of liquids and equipment containing or contaminated with PCB is much larger than the amounts of pure PCB produced: a single tonne of PCB can generate multiple tonnes of PCB wastes.

A global treaty to protect human health and the environment from POPs

Entered into force in 2004, the Stockholm Convention on persistent organic pollutants obliges countries to eliminate the use of PCB in equipment by 2025 and make determined efforts to lead to the environmentally sound management of waste liquids and equipment contaminated with PCB by 2028. The production of PCB and new uses are prohibited, and equipment containing PCB shall not be exported or imported except for the purpose of environmentally sound waste management. PCBs have been listed on Annex A of the convention as part of the 12 initial POPs, as industrial chemicals and unintentional by-products. To date, 185 countries have ratified the Convention.

The 10th Conference of the Parties requested the Secretariat of the Stockholm Convention, in consultation with the small intersessional working group, to prepare three documents for consideration at its 11th meeting on May 2023.

A report on progress towards the elimination of PCB (UNEP/POPS/COP.11/INF/11)
Guidance for development of PCB inventories and analysis of PCB (UNEP/POPS/COP.11/INF/12)
A draft strategy for Parties to meet the 2025 and 2028 goals of the Stockholm Convention (UNEP/POPS/COP.11/INF/13)

and, subject to the availability of resources, to continue to participate in the activities of the Polychlorinated Biphenyls Elimination Network (PEN).

Progress toward elimination of PCB - Are we on track?

The progress in eliminating PCB varies considerably across UN regions. In January 2016 UNEP estimated that only 3 million tonnes (17% of total) of equipment and materials containing PCB (transformers account for the largest share of the total mass) have been eliminated, at the rate of about 200,000 tonne/year since 2000. 14 million tonnes (83% of the total) are still to be eliminated.

Addressing the remaining 83% would require the elimination of 1 million tonnes of PCB-containing oils and contaminated equipment per year to reach the 2028 target. Only 30% of the countries are on track to reach the 2025 and 2028 goals.

The quantities of PCB (in use in equipment, stored, eliminated) are estimated based on national reporting as well as answers to an online survey and a questionnaire. Information provided by countries reporting to the Basel Convention on PCB import and export (allowed for the purpose of environmentally safe waste management) are also taken into consideration. The "Report on progress towards the elimination of polychlorinated biphenyls", in February 2019 (UNEP/POPS/COP.9/INF/10) highlights the difficulties in estimating quantitative PCB data due to:

Incomplete national reporting (at the time the report is written, six months after the deadline for submission, only 59 Parties out of 182 have submitted their fourth national report)
Limited coverage of voluntary answers to survey and questionnaire
Incomplete and inconsistent inventories: countries report differently on equipment containing PCB in operation, equipment that has been decommissioned and stored waiting for proper final management, oil and other contaminated liquids, other contaminated materials, and on PCB in open applications (not an obligation under the Stockholm Convention)
Lack of analytical methods to identify waste containing PCB,
Diverse interpretation of the of the meaning of “PCB in use”

Parties are requested to report every 4 years on their implementation of their obligations under the Stockholm Convention. The Reporting Dashboard allows to see each country submission as well as interesting graphics and charts on data including PCBs.

PCBs Production and Elimination Timeline — *Figure adapted from Melymuk et al. 2022, Environ. Sci. Technol. 56, 9029−9040*

The Environmentally Sound Management of hazardous chemicals like PCBs plays an important role in successfully completing the Sustainable Development Goals.

SDG 3 SDG 3. Good health and well-being: PCBs concentrations exceeding the standards can negatively affect human health and well-being.

SDG 9. Industry, innovation and infrastructure: New innovative technologies and use of alternative products with regard to PCBs are part of sustainable industrialization.

SDG 14. Life below water: Improving the management of PCBs and reducing releases into the environment is an important intervention to protect the world’s oceans, seas and marine resources.

Further Resources

Polychlorinated biphenyls Phase-out Plan UNEP, 2023
PCBs in the Stockholm Convention
Draft Guidance for Development of PCB Inventories and Analysis of PCB (UNEP/POPS/COP.10/INF/12/Rev.1) February 2022
GEF Projects on PCBs
Consolidated Assessment of Efforts Made Toward the Elimination of PCB January 2016
PCB Management Guidance - Maintenance, Handling, Transport and Interim Storage of Liquids Containing PCB and Equipment Contaminated with PCB October 2016
Polychlorinated Biphenyls (PCB) Inventory Guidance February 2016

PCB in Open Applications

Consolidated Guidance on PCB in Open Applications March 2019
PCB-Open Applications: Identifications and Environmentally Sound Management July 2014
PCB in Open applications: Machinery and Installations May 2015
PCB in Open applications: Residential and Public Buildings May 2014

Webinar series: PCB - A forgotten legacy?

The PEN, in collaboration with UN Environment Chemicals and Health Branch and the United Nations Institute for Training and Research (UNITAR) developed a webinar series.

Webinar 25 October 2016