Chemical characteristics and sources of precipitation around Qinghai Lake valley, NW China

A total of 33 precipitation samples have heen colle cted from individual precipitation events at the hird island, a sc enic zone of Qinghai Lake Monitoring (36° 32´ ~37° 15´ N, 99° 36´ ~100° 16´ E; 3200 m a.s.l) located in the northwes t of Tibetan Plateau from June 2010 to August 2010. All samp les were analyzed for major cations (NH₄⁺,Na⁺,K⁺,Ca²⁺ and Mg²⁺) and anions (F^-,Cl^-,NO₃^- and SO₄^2-), conductivity, pH and DO C (Dissolved Organic Carbon). The pH value of precipitation r anged from 6.05 to 8.19 with a volume average value of 7.13. Ca²⁺ is the dominant cation in precipitation with a VWM of 125.08 μeqL^-1 (1.62-664.21 μeqL^-1), accounting for 27% of the total cations in precipitation. HCO₃^- is the predominant anion with a VWM of 125.09 μeqL^-1, accounting for 26% of the tot al anions. Correlation and Enrichment factor analysis (EF) indie ate that crustal aerosols from combustion emissions of residents and continental dust, which are the major sources for these ions.