[Concentrations and Solubility of Trace Elements in Atmospheric Precipitation in Qingdao].

Thirty-five atmospheric precipitation samples were collected at an urban site in Qingdao from June 2016 to May 2017. The total and soluble concentrations of eight trace elements in the samples were determined, and the variable characteristics of the concentrations and solubility of trace elements, as well as the factors affecting the solubility of trace elements in atmospheric precipitation, have been discussed. Based on the overall data, the total concentrations of the trace elements were found to be in the order Al > Fe > Zn > Mn > Ba > Pb > Sr > V, but the soluble concentrations of the trace elements were in the order Zn > Al > Mn > Fe > Ba > Sr > Pb > V. Solubility was about 5% for the crustal elements Al and Fe, and the solubility of the elements affected by anthropogenic sources was relatively higher, 10%-40% for Pb and Ba, 20%-60% for Mn and Sr, and nearly 55% for Zn and V. The total and soluble concentrations of the trace elements were higher in winter and spring than in summer and autumn, but element solubility in spring was the highest. During continuous rainfall, the total concentrations of trace elements in precipitation decreased appreciably, but the variation trend of the solubility of trace elements was not consistent during the different rainfall processes. The variation in pH was the main factor controlling the solubility of trace elements in precipitation.