Major ion geochemistry and anthropogenic impacts on the Minjiang River, Sichuan

The Minjiang River has a flow capacity of 8.9×10¹⁰ m³/yr, about 10% of that of the Changjiang River. The analysis of the data from four hydrologic stations has disclosed that the TZ⁺ values for the Minjiang River are higher than the mean values for othe rivers in the world. The river water is HCO₃^- and Ca-rich. The total chemical denudation flux in the Minjiang River is 20.48×10⁶ t/yr, about 13% of that of the Changjiang River. The chemical denudation rates are 155.9 t/km² per year. Since the Minjiang River flows through the densely populated Sichuan Basin, the concentrations of major ions such as SO₄, Cl and Ca are seriously influenced by the anthropogenic factors:SO₄ mainly from the acidic rain; Cl from domestic sewage and industrial waste water, chemical fertilizer and salt production, and Ca from Ca-rich chemical fertilizer.