Ecological Risk Assessment of Organophosphate Flame Retardants in Rainwater Pipeline Sediments

Abstract

Organic phosphorus flame retardants (OPFRs) have garnered significant attention due to their recent emergence as contaminants with widespread distribution in aquatic environments, posing potential threats to humans and ecosystem health. Introduced into flame retardants and polymers through non-chemical bonds, OPFRs readily permeate the environment through volatilization, product wear, and leakage, increasing the risk of pollution in urban areas. This study employed a gas chromatography-mass spectrometer to quantitatively analyze the content and distribution characteristics of 12 typical OPFRs across 21 locations in Guangzhou’s main urban areas. The results reveal concentrations ranging from 0.191 to 0.950 μg/g (averaging 0.394 μg/g), indicating a moderate pollution level compared to road dust, rivers, lakes, estuarine sediment, and rainwater pipe sediment. Key OPFRs identified include tributoxyethyl phosphate (TBEP) and tricresyl phosphate, with TBEP exhibiting the highest concentration. Correlation studies suggested that OPFRs have point-source characteristics, while principal component analysis indicated that rainwater runoff, atmospheric settlement, and industrial and commercial sewage discharge as significant contributors to sediment OPFRs. Our findings emphasize the importance of implementing rain and sewage diversion systems in commercial districts and advocating regular sediment cleaning and transfer to sewage treatment plants. In addition, improving sewage treatment processes is essential for enhancing the removal efficiency of OPFRs and addressing their adverse impacts on the environment and human health.