Metal bioaccumulation by plants in roadside soils: Perspectives for bioindication and phytoremediation

Traffic-related metal pollution is a serious worldwide concern. Roadside soils are constantly subjected to the deposition of metals released by tailpipe gases, vehicle parts, and road infrastructure components. These metals, including platinum group elements from catalytic converters, constitute a threat to surrounding ecosystems that frequently comprise pasture and agricultural lands. Due to the capacity of plants to tolerate and accumulate metals, the study of the vegetation growing in soils adjacent to roads is important to understand their role as bioindicators of trafficrelated metal pollution and infer their potential for the phytoremediation of roadside areas. This chapter reviews the main sources of metals in roadside soils and dusts, and the bioaccumulation of metals in plants growing alongside roads presenting different traffic loads and climatic conditions. The pertaining literature is discussed with a particular emphasis on the suitability of the assessed plant species to indicate and mitigate traffic-related metal pollution.