Chemical weathering and CO 2 consumption in the Wuhua River basin,eastern Guangdong Province

Measurements of physicochemical components in the mainstream and tributaries of the Wuhua River system and application of methods of mass-balance and Pearson correlation analysis were conducted to investigate the atmospheric CO2consumption caused by rocks chemical weathering processes in the subtropical humid mountainous and hill region.Results show that the average concentration(77.11mg/L) of the total dissolved solids within the Wuhua River was close to that(65 mg/L) in the world rivers,dominated by ions of Ca2+,Na+ and HCO-3 and followed by dissolved Si;ions of Ca2+,Na+ and HCO-3 were characterized by the effect of runoff dilution.Chemical runoff in the Wuhua River was dominated by silicate mineral weathering,followed by carbonate mineral.Atmospheric and soil CO2 were major erosive mediums during rocks chemical weathering in the basin,with acids precipitation as the secondary erosive mediums.Comparatively,the atmospheric CO2 consumption flux(2.14×105 mol/(km2·a)) by the rock chemical weathering processes in the Wuhua River basin is lower than that of the world.This is in agreement with the distribution of extensively rocks composed of silicate minerals,sparsely rock containing carbonate minerals.