Determination of the geochemical baseline for the East River basin, China

Abstract

Baseline information serves as a point of reference against which future natural or anthropogenic changes to geochemistry may be evaluated. It may also serve to identify controls, such as rock type, upon geochemistry and has other applications. In 2007-2009, active stream sediment samples from the East River in China were collected and analysed in an attempt to develop a geochemical baseline. Sample density is around 1 per 200 km2, covering a total area of 27 600 km2. Situated in southern China, the East River basin contains three large reservoirs that are of great importance to flood control, power generation, shipping, and water supply in the region. The watershed is well vegetated and woodlands occupy ∼75% of the basin area. The geology is heterogeneous: sedimentary units of various ages have been intruded by igneous rocks. In 2007, the population living within the watershed was some 12 million. The concentration ranges of the elements are consistent with average crustal values. The spatial variation of the geochemistry reveals that it is affected by both natural and anthropogenic factors. Copyright © 2010 IAHS Press.