POPs and Hazardous Substances in Construction and Demolition Waste

The Challenge

Construction and Demolition (C&D) waste is the largest waste stream in the UK Although the majority of this is mineral based (such as concrete, bricks and soil), significant quantities of polymer-based products such as plastics, rubbers, foams, adhesives and sealants are discarded of each year.

Polymers are widely used in construction products. Additives impart improved performance characteristics, such as UV resistance and flame retardancy. However, many of these added substances have subsequently been classified with hazard statement codes, and some have been identified as persistent organic pollutants (POPs).

As a result, there is a possibility that C&D products made from polymers such as plastics and rubber may be classified as hazardous and/or POPs, impacting how this waste is managed. Work was commissioned by the Environment Agency to understand which substances were in which products, and the concentrations at which they were present. The project was carried out between December 2023 and March 2026.

The Solution

Working with waste management companies, WRc undertook a comprehensive sampling exercise to collect over 1000 individual items of waste construction products. These were sorted into categories such as insulation, flooring and window and door frames. Each sample was scanned using x-ray fluorescence to provide a semi-quantitative elemental composition. Using this data, alongside knowledge on the use of specific additives in certain products, WRc worked with the EA to select 200 samples for semi-quantitative chemical screening. This chemical screening included POPs such as polybrominated diphenyl ethers (PBDEs) and short chained chlorinated paraffins (SCCPs) as well as classified substances including a range of brominated flame retardants (BFRs), organophosphate flame retardants, phthalates and PFAS. This chemical screening was used to select samples for quantitative analysis.

Following a review of the initial data set, additional data was obtained on the concentration of SCCPs and medium chained chlorinated paraffins (MCCPs) in products where data was lacking such as vinyl flooring, window and door frames and traffic management products. Further data on BRFs in expanded polystyrene (EPS) and extruded polystyrene (XPS) insulation was also sought.

The Outcome

Based on the quantitative data, WRc identified that POPs were detected above relevant thresholds in 13 samples. MCCPs, although not yet a POP, were found in 20 samples at concentrations over 10,000 mg/kg.

• Polybrominated diphenyl ethers (PBDEs) were detected in seven samples of insulation at concentrations exceeding 500 mg/kg.
• Hexabromocyclododecane (HBCD) was detected in five insulation samples, with one exceeding the POPs waste limit of 1,000 mg/kg. The analysis of HBCD in insulation foams is considered particularly difficult, and it is possible that the reported quantitative results may underestimate the true levels due to the nature of bromine measurement and the established use of HBCD in these applications.
• Short chain chlorinated Paraffins (SCCPs) were only present above the 10,000 mg/kg threshold in a single sample of expanding filler. While not prevalent in other key product categories, SCCPs were detected in traffic management products made from recycled PVC cable granulate at levels between 1,000 and 2,000 mg/kg.
• Medium chain chlorinated paraffins (MCCPs) are not currently classified as POPs. They were detected in 20 samples at concentrations above 10,000 mg/kg, with a notable prevalence in expanding fillers. Additional analysis showed that MCCPs were not widespread in other key product categories, but traffic management products manufactured from recycled PVC cable granulate contained MCCPs at concentrations ranging from 5,000 to 10,000 mg/kg.
• Per- and polyfluoroalkyl substances (PFAS) were not detected in any of the 20 samples analysed above the limit of detection (LOD) (5 µg/kg)
• Dechlorane plus was detected in one sample above 100 mg/kg, and UV328 was not detected in any sample above the LOD of 200 mg/kg.
• Organophosphate flame retardants were found in the majority of electrical fixtures, fittings, and expanding filler samples tested, with concentrations exceeding relevant hazardous property thresholds. This indicates a widespread presence of these substances in such products.
• Phthalates classified with hazard statement codes such as DEHP were present in products like vinyl flooring, but their prevalence was lower than anticipated. This suggests that a significant proportion of the waste materials originated from products manufactured after the implementation of bans on these substances.
• Lead was detected in 67% of door and window frames at concentrations above 2,500 mg/kg, exceeding hazardous property thresholds.
• Zinc analysis showed that 25% of rubber products contained zinc at concentrations above 2,500 mg/kg, also exceeding thresholds.

C&D waste is highly variable, making it difficult to characterise. This study provides product specific evidence on hazardous and POPs substances to support more accurate waste classification and segregation – facilitating recycling where appropriate and separate collection and treatment where needed.

WRc were not involved in, or had any influence over, any subsequent classification decisions made by the Environment Agency for C&D waste. The project was solely to collect and evaluate data