Five-year monitoring study of chemical characteristics of Wet atmospheric precipitation in the southern region of Jordan.

Wet atmospheric samples were collected from different locations in the southern region of Jordan during a 5-year period (October 2006 to May 2011). All samples were analyzed for pH, EC, major ions (Ca(2+), Mg(2+), Na(+), K(+), HCO3(-), Cl(-), NO3(-), and SO4(2-)), and trace metals (Fe(2+), Al(3+), Cu(2+), Pb(2+), and Zn(2+)). The highest ion concentrations were observed during the beginning of the rainfall events because large amounts of dust accumulated in the atmosphere during dry periods and were scavenged by rain. The rainwater in the study area is characterized by low salinity and neutral pH. The major ions found in rainwater followed the order of HCO3  >  Cl(-) >  SO4(2-) and Ca(2+) >  Na(+) > Mg(2+) > NH4(+) > K(+). Trace metals were identified to be of anthropogenic origin resulting from cement and phosphate mining activities located within the investigated area and from heating activities during the cold period of the year (January to April). The wet precipitation chemistry was analyzed using factor component analysis for possible sources of the measured species. Factor analysis (principal component analysis) was used to assess the relationships between the concentrations of the studied ions and their sources. Factor 1 represents the contribution of ions from local anthropogenic activities, factor 2 represents the contribution of ions from natural sources, and factor 3 suggests biomass burning and anthropogenic source. Overall, the results revealed that rainwater chemistry is strongly influenced by local anthropogenic sources rather than natural and marine sources, which is in a good agreement with the results obtained by other studies conducted in similar sites around the world.