The Impact of Continuous Heavy Metal Emissions from Road Traffic on the Effectiveness of the Phytoremediation Process of Contaminated Soils

Heavy metals are among the most toxic and persistent environmental pollutants, accumulating in soils and living organisms. Phytoremediation, the use of plants to remove contaminants, is considered one of the promising methods for cleaning soils contaminated with metals. This study assessed the effectiveness of phytoremediation of heavy metals in soil using lettuce (Lactuca sativa) as a phytoaccumulative species. Despite the successful extraction of significant amounts of metals by the plants, post-harvest soil analysis revealed persistently elevated concentrations of elements such as iron (Fe), lead (Pb), and zinc (Zn). To clarify the reasons behind the limited improvement in soil quality, additional field investigations were conducted and identified a nearby highway as a continuous source of heavy metal emissions. In the next phase of the study, metal concentrations were analyzed in dust deposited along the highway, confirming their significant contribution to ongoing secondary soil contamination. The findings emphasize the importance of considering both environmental and anthropogenic factors when designing long-term phytoremediation strategies in urban and traffic-impacted areas.