Potentially Toxic Metals (PTMs) in Soil-Dust-Plant Total Environment and Associated Exposure Risks for Children (0–6) Based on Site-Specific Blood Lead Levels: A Comprehensive Investigation for the City of Lanzhou in Northwest China

Systematic understanding of the status of potentially toxic metals (PTMs) in soil, dust and plant is of great need for their negative impacts on human and environmental health. Characterization and screening of PTMs will play an important role in health risk assessment and pollution control. In this study, a comprehensive investigation is conducted to explore the spatial occurrences, pollution status and health risks of 19 PTMs and 6 major elements (As, Ba, Ce, Co, Cr, Cu, Ga, La, Mn, Ni, Pb, Rb, Sr, Th, U, V, Y, Zn, Zr, Al, Ca, Fe, K, Mg, Na) in urban soil, street dust and plants in the City of Lanzhou in northwest China. Most PTMs in urban soil, dust and plant have similar spatial patterns and pose pollution to some extent. The priority metals Pb, Cu, Zn from traffic sources have similar tendency transferring among soil-dust-plant environment in comparison to other metals which prefer to accumulate in dust. PMF analyses confirm that coal combustion and industrial emission are important origins for metals in addition to traffic sources. Total carcinogenic risk of toxic metals in dust and soil for children are unacceptable compared to adults. Site-specific blood lead levels (BLLs) are predicted according to the occurrences of priority contaminant Pb in the urban environment. Children of less than three years old have higher BLLs than those of 4–6 years old. The highest BLL for children of 1–2 years old is up to 90 μg·L −1 , which is almost twice the US CDC Acceptable Threshold (50 μg·L −1 ) even though it is still below the China Acceptable Limit (100 μg·L −1 ). Therefore, attention to Pb contaminant prevention and measurement including complete environmental cleaning and screening of BLLs periodically for children 0–6 years old.