Identification, classification and quantification of microplastics in road dust and stormwater

Microplastics (MP) have become a major emerging class of pollutants representing significant eco-toxicological risks for ecosystems and marine environments. The aim of this study was to identify, classify and quantify MP present in both road dust and stormwater samples. A significantly higher level of MPs within road dust samples was detected from industrial area (1130 particles/kg of dust) than from residential area (520 particles/kg of dust), while stormwater samples from industrial and residential sites yielded 26 particles/L and 17 particles/L, respectively. Fiber-like shape accounted for 53% and 74% in road dust and stormwater samples, respectively. The main polymeric materials collected for both road dust and stormwater samples were, in order of occurrence (i) low-density polyethylene, (ii) high-density polyethylene, (iii) polypropylene, (iv) polyethylene terephthalate, (v) polystyrene, (vi) polyester and (vii) poly (amide). Most of the MP had an average maximum dimension smaller than 2 mm for both road dust and stormwater samples. The results from this study demonstrates that road dust is a significant contributor to MP pollution through direct polymeric materials wear off and transfer through stormwater, which eventually will end up in open water ways and broader ecological niches.

Automated summary

Microplastics have emerged as significant pollutants posing eco-toxicological risks to ecosystems and marine environments. Road dust is a major contributor to microplastic pollution, transferring through stormwater to open water ways and broader ecological niches.