Researchers detect a potentially harmful substance in solid waste

Chlorinated organophosphorus esters, used as flame retardants, can cause toxic effects on the endocrine and reproductive systems and possibly lead to cancer.

By Thais Szegö  |  Agência FAPESP – In a study conducted by São Paulo State University (UNESP) in Brazil and the University of Birmingham in the United Kingdom, the presence of chlorinated organophosphorus esters was identified in samples of solid waste – discarded materials that could be used by others. 

These substances are used in industry as flame retardants and plasticizers. Due to their thermal stability and low cost, they are widely used in products such as polyurethane foam for furniture and mattresses, plastic casings for electronic products, children’s items, and insulation foam for construction. 

The most common of these compounds are tris(1-chloro-2-propyl) phosphate (TCIPP), TDCIPP, and TCEP. They have the potential to be toxic and cause damage to the endocrine and reproductive systems, as well as potentially contribute to the development of cancer. Exposure can occur through direct contact with objects containing these compounds, or through ingestion or inhalation of dust released into the environment as these materials degrade.

Children’s products warrant special attention because these compounds have been found in car seats, crib mattresses, plastic toys, and other items that often contain polyurethane foam or treated plastics. 

Furthermore, studies have shown that children have higher concentrations of these compounds in their bodies due to their frequent contact with these products and tendency to put their hands in their mouths after handling toys or objects treated with these compounds.

A total of 207 samples were collected from four categories: construction and demolition waste, end-of-life vehicles, upholstered furniture, and childcare products. These categories were selected because they are most likely to contain materials with chlorinated organophosphorus esters in Brazil. 

The material came from the Sorocaba metropolitan area in São Paulo and was collected from various sources, including a vehicle dismantling facility, a construction and demolition waste landfill, recycling associations, and companies that manufacture or refurbish upholstered furniture.

“Our results showed that 95% of the samples contained at least one of these compounds at low concentrations, with 13 exceeding the level of greatest concern,” says David Burgos Melo, an environmental engineer at UNESP who coordinated the study, whose results were published in the journal Environmental Pollution.

The research, which was supported by FAPESP (projects 21/11549-0, 22/00985-6, 22/14797-7, 23/14685-7, 24/16955-4, and 25/11187-1), is of the utmost importance since Brazil generates approximately 81 million metric tons of municipal solid waste and 46.4 million metric tons of construction and demolition waste per year, making it the second-largest generator in the Americas. Some of these materials are reused in the production of new goods, which can lead to new forms of contamination. Others are disposed of without oversight. 

Some flame retardants have been banned by international treaties, such as the Stockholm Convention, which was created to protect human health and the environment from persistent organic pollutants. Brazil has been a signatory to this treaty since 2004. The United Kingdom, China, and Japan, for example, have already implemented policies to prevent these items from being disposed of improperly or reintroduced into the production cycle to create new products.

“However, banning the production of new products containing these compounds won’t make the materials that have already been produced disappear. If they’re recycled without chemical analysis and/or prior treatment, these substances migrate into new items or impact the environment, causing problems for wildlife or human health,” Burgos explains. 

“When the study began, there was virtually no data on the levels of these substances in waste from Brazil and Latin America. Without this information, any discussion of safe waste management or the protection of recycling workers lacks a scientific basis. That’s what led us to conduct research on this topic,” he adds. 

According to Burgos, another important point is that brominated compounds, the first flame retardants recognized as persistent organic pollutants and included in the Stockholm Convention, which led to their ban, were replaced by chlorinated organophosphates. These compounds are not regulated in the same way, are toxic, and have documented carcinogenic potential. In the literature, this is called “regrettable substitution” – that is, replacing one problematic substance with another that is equally problematic.

“Brazil has recycling targets and promotes reverse logistics for electronics through the National Solid Waste Policy – and all of that is necessary. But our results show that recycling without chemical sorting can turn the circular economy into a vector for the recirculation of contaminants. Toxic substances from an old product end up in a new one,” he states. 

The article “Chlorinated organophosphate esters in Brazilian solid waste: concentrations, national load estimates, and regulatory implications for a circular economy” can be read at www.sciencedirect.com/science/article/pii/S0269749126005993.