Lead accumulation in edible portions of crops grown near Egyptian traffic roads

Accumulation of lead in different parts of vegetables growing around six Egyptian traffic roads was investigated. Results of this work showed that leafy vegetables such as lettuce and cabbages accumulated lead up to 78.4 p.p.m. in their edible portions while the least lead accumulators were carrots and radish. The highest concentration of lead found in carrots sampled from locations adjacent to the busiest traffic road was 10.2 p.p.m. with an average concentration of 3.8 p.p.m. Lead concentrations in fruits of pepper and tomato were in the range of 0.7–18.6 p.p.m. depending on several factors such as traffic densities and distances from the road. The average ratio between lead in soil to lead in fruit of tomatoes at the first 10 m from roads was about 15 compared with a ratio of 50 at distances more than 100 m. These findings suggest that lead was accumulated in plants through both foliage and root systems, but lead absorption through foliage is more pronounced at locations close to the emission source of lead vapour and fine particles. The concentration of lead in fruit was dependent on its concentration in the leaf rather than in the roots or soil.