NATIONWIDE RIVER CHEMISTRY TRENDS IN CHINA - HUANGHE AND CHANGJIANG

Concentrations of trace metals and nutrient elements from Chinese rivers were examined on the basis of high-quality analyses and monitoring data. Routine monitoring practices may provide trace-metal levels two or three orders of magnitude higher than those from high-quality analyses. This is most likely due to the contamination and defects associated with sample collection and analysis. Elevated nutrient concentrations in Chinese rivers are attributed to extensive agricultural activities, e.g. use of chemical fertilizers. Riverine concentrations of nutrients have doubled over the last decade. Taking into account the higher demand for crop production, nutrient levels can be expected to continue to increase in the near future. This will have an important influence on bioproduction in coastal waters unless effective environmental management and protection are introduced.