A global UN-led study reveals persistent organic pollutants (POPs) remain in our environment despite bans. Found in air, water, food, and even human milk, these long-lasting toxins raise concerns.
The study, implemented by UN Environment Programme (UNEP) and funded by the Global Environment Facility (GEF), stresses the importance of POPs monitoring, caution in introducing alternatives, and addressing gaps in awareness and regulation.
The study was conducted across 42 countries in regions where data on POPs is limited, including Africa, Asia, Latin America and the Caribbean, and the Pacific Islands to monitor 30 POPs listed under the Stockholm Convention as of 2021. Samples were collected between 2016 and 2019.
The data is published as governments gather this week in Geneva for an ad hoc open-ended working group on the establishment of a science-policy panel on chemicals, waste and pollution prevention.
Persistent Organic Pollutants (POPs) are organic chemical substances, meaning they are carbon-based. These pollutants possess a unique combination of physical and chemical poperties. Once released into the environment, they are toxic to both humans and wildlife. Furthermore, POPs are linked to cancer, liver damage, decreased fertility, and increased risk of asthma and thyroid disease due to their endocrine disrupting properties.
“POPs remain omnipresent, despite efforts to reduce their use and production,” said Andrea Hinwood, UNEP’s Chief Scientist. “Monitoring the concentrations of POPs in the environment and in our own bodies is vital, especially in low- and middle-income countries, to support their assessment of contamination, emissions, and exposure to POPs for informed decision making.”
The list of 30 POPs monitored in the study includes pesticides and industrial chemicals, as well as unintentionally released POPs that are by-products of industrial processes and from incomplete combustion (e.g., open burning of waste). They were found in every one of more than 900 collected samples, with over 50,000 data points generated on POPs in air, water, human milk, soil, beef, milk, milk powder, butter, mutton, pork, chicken, eggs, fish and shellfish, oil, and other items.
Data shows a global decline in the levels of 12 POPs initially listed in the 2004 Stockholm Convention; the report credits this trend to regulatory actions taken since. The use of DDT – once deployed in agriculture and now highly restricted – has decreased in human milk samples by over 70 per cent since 2004 on global average. Nevertheless, DDT remains the most prevalent POP in human milk, particularly in countries where it was intensively used.
“POPs monitoring is essential for evaluating the real-world impact of global actions,” said Rolph Payet, Executive Secretary of the Basel, Rotterdam and Stockholm Conventions. “The scientific findings not only illustrate the achievements of collective global efforts, but also highlight the urgent need of intensifying global initiatives to protect the health of humans and the environment.”
“GEF will continue to support and enhance POPs monitoring on a global scale,” said Anil Sookdeo, GEF’s Coordinator for Chemicals and Waste. “A new programme is being developed, building on the experience gained and including newly listed POPs and mercury (Hg).”
The study finds other POPs are present everywhere, including in areas far from any known source of contamination. Long-regulated chemicals, such as dieldrin and polychlorinated biphenyls (PCBs), were detected at elevated levels in the air across the African continent, the Caribbean, and Latin America.
Some banned chemicals have been replaced by the industry with other chemicals, which were later found to also have POPs properties, such as per-and polyfluoroalkyl substances (PFAS). Of the thousands of PFAS, three key chemicals (PFOS, PFOA, PFHxS) are listed under the Stockholm Convention. All of them were found in human milk. PFAS were also found in drinking water in remote islands, in levels far exceeding European Union and United States standards.
Newly listed POPs are increasingly difficult to monitor, even by the world’s top laboratories. While data collection is improving, with more labs in low-income countries participating in POPs monitoring, including in the UNEP global interlaboratory assessments, the quality of POPs analysis must continue to improve.
“Governments need not be pulled into a toxic game of hide and seek, where one regulated POP is replaced with a new one. This troubling pattern means these substances are still present in products we use, eat, wear, as well as in our air and water,” said Jacqueline Alvarez, Chief of the Chemicals and Health Branch of UNEP. “This highlights the risk of regrettable substitutions of banned POPs and the need to prioritize sustainability in industrial product design and consumer behaviour.”
UNEP will continue supporting governments and work with industries to address POPs, identify areas in need of immediate attention, track the progress of pollution reduction efforts, and take action to prevent further contamination.
