Concentration variations of several ions in stream after a wildfire

In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing'an Mountains, China. The concentration changes of eight ions (K , Na , Ca2 , Mg2 , Cl-, Br-, NO3- and SO42-) were measured in burned and unburned streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca2 , whose average concentration was 5.50 mg·L-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca2 ＞ SO42- ＞Na ＞ Mg2 ＞ NO3- . The average concentrations of Ca2 , SO42-, Na Mg2 , NO3- showed an increase trend,but those of K , Cl-, Br- had a decreased trend. SO42- had the largest loss among these anions, followed by NO3-. Overall, the increase degree of cation was greater than that of anion after burning.