A new laboratory study has found that non-metal roofing materials, widely used in residential and commercial construction, may release hazardous pollutants into stormwater runoff, potentially affecting water quality and public health. The findings underscore a growing need to re-evaluate roofing materials in the context of environmental sustainability and urban water management.
Key Highlights:
- Concrete and fiber-cement roofs released biocides, particularly terbutryn.
- Treated wood shingles emitted ammonium, boron, copper, and Bisphenol A.
- Clay tiles were identified as a source of vanadium, and many also leached manganese and arsenic.
- Bitumen shingles released Bisphenol A, a known endocrine disruptor.
- The main mechanism of pollutant release was identified as diffusion.
Study Overview
Researchers conducted controlled leaching tests on six commonly used non-metal roofing materials: clay tiles, concrete tiles, fiber cement, wood shingles, bitumen shingles, and plastic roofing. The analysis focused on pollutants frequently detected in stormwater, including heavy metals, biocides, phthalates, PFAS, PAHs, and endocrine-disrupting chemicals like Bisphenol A.
The materials underwent eight leaching cycles, simulating stormwater interaction over time. The study revealed that even non-metal surfaces, often considered environmentally benign, can significantly contribute to urban water pollution.
Environmental and Regulatory Implications
The findings challenge the prevailing focus on metal roofs as primary pollution sources and highlight the need for further long-term field studies. The data also suggest a potential need for updated regulations and stormwater treatment technologies to address runoff from a broader range of roofing materials.
The study’s authors call for further research into real-weather leaching dynamics and the development of on-site treatment systems to mitigate the environmental impact.
Conclusion
This new evidence positions non-metal roofing materials as underestimated contributors to stormwater pollution, urging architects, builders, and policymakers to reconsider material choices and invest in sustainable roofing solutionsthat protect water quality.
