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

摘要

A total of 33 precipitation samples have been colle cted from individual precipitation events at the bird 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 (NH_4~+,Na~+,K~+,Ca~(2+)and Mg~2 +) and anions (F~-,C1~-,NO_3~- and S0_4~(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. Ca~(2+) 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. HCO_3~- 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) indic ate that crustal aerosols from combustion emissions of residents and continental dust , which are the major sources for these ions.