Lead seasonality: Affect children's blood lead levels and implication for lead exposure prevention.

Lead seasonality attributed to the patterns of Pb variation in the natural environment should be considered in the Pb risk analysis and related to the seasonality evident in humans. In this study, we integrate the Xi'an soil and dust lead seasonality data (554 surface soil samples and 554 road dust samples in three seasons) to evaluate the seasonal lead burden on children and propose the implications for children's lead exposure prevention strategies considering the lead seasonality and the influences from urban land use and children's living environment. The results showed that most seasonal variation patterns of soil and dust Pb are observed in winter (cold season), which coincided with the observation of higher children's blood lead levels in winter, although the strong correlation coefficients between children's blood lead levels (BLLs) and soil/dust Pb are observed in summer. The combinations of meteorological factors and anthropogenic pollutant emission strongly determine the metal seasonal variations. Those arrays of evidence suggest that lead seasonality is multifactorial within the environment and humans. Land uses and living environments such as old residential areas, heavy traffic, and fewer green parks, etc. have a significant impact on the increase of children's BLLs. Lead exposure prevention is proposed by BLLs warning and effective measure of reduction ≤ 50 μm soil/dust size fraction in winter.