Xiao-Huan Liu

Evaluation of trace elements contamination in cloud/fog water at an elevated mountain site in Northern China.

Totally 117 cloud/fog water samples were collected at the summit of Mt. Tai (1534m a.s.l.)-the highest mountain in the Northern China Plain. The results were investigated by a combination of techniques including back trajectory model, regional air quality and dust storm models, satellite observations and Principal Component Analysis. Elemental concentrations were determined by Inductively Coupled Plasma Mass Spectrometry, with stringent quality control measures. Higher elemental concentrations were found at Mt. Tai compared with those reported by other overseas studies. The larger proportions and higher concentrations of toxic elements such as Pb and As in cloud/fog water compared with those in rainwater at Mt. Tai suggests higher potential hazards of cloud/fog water as a source of contamination in polluted areas to the ecosystem. Peak concentrations of trace elements were frequently observed during the onset of cloud/fog events when liquid water contents of cloud/fog water were usually low and large amount of pollutants were accumulated in the ambient air. Inverse relationship between elemental concentrations and liquid water contents were only found in the samples with high electrical conductivities and liquid water contents lower than 0.3gm(-3). Affected mainly by the emissions of steel industries and mining activities, air masses transported from south/southwest of Mt. Tai were frequently associated with higher elemental concentrations. The element Mn is attributed to play an important role in the acidity of cloud/fog water. The composition of cloud/fog water influenced by an Asian dust storm event was reported, which was seldom found in the literature.

Characteristics of Heavy Metals in Wet Deposition at Mt. Tai, China

130 wet deposition events were observed at the summit of Mt. Tai (East China, 1534 a.s.l) in China during Jan. 2005 to Dec. 2008. Zn, Al, Mn, Fe, Pb, Cu, Ni, Cr, As, and Cd were determined by ICP-MS to evaluate the characteristics of heavy metals in wet deposition at Mt. Tai region. The concentrations of these metals are generally higher at Mt. Tai than the concentrations observed at other monitoring sites around the world. Element Zn is the most abundant heavy metal through entire observation period, accounting for 46% of the total metals concentrations in rainwater, with volume-weighted mean (VWM) concentrations of 90.60g/l. Among the relatively more concerned elements which are toxic at very low amount (i.e., As, Pb, Ni, Cd, Cr), the primary is Pb, with VWM concentrations of 6.48g/l. Highest concentrations of heavy metals are observed in Nov. and lowest in Feb. Based on the correlation analysis, elements As, Mn and Cd are strongly related; moderate correlations are found between elements Al and Fe, Cu and Zn. indicating similar sources of these elements.