Multi-element geochemistry of sediments from the Pearl River system, China

Sediment samples were taken along the West, North, and East rivers of the P earl River system at 28 locations in 1998, and a total of 49 elements were determined by ICP-AES, ICP-MS and INAA. The probability features of the dat asets were studied, and the average concentrations of these elements in sed iments of the three rivers were calculated. Significant differences in elem ent concentrations among the three rivers were observed and the results wer e confirmed by statistical tests including analysis of variance (ANOVA), Kr uskal-Wallis test, and t-test. Spatial distribution maps of element concent rations were produced using a geographical information system (GIS). The im mobile trace elements (such as Sc, Ti, V, Cr, Mn, Fe, Co, and Ni) are enric hed in the West River where limestone dominates the rock types in the water shed. Because of the strong weathering, immobile trace elements are enriche d and reside in secondary minerals of the weathering products. All three ri vers have high concentrations of rare earth elements (REEs) because of stro ng weathering, but relatively higher concentrations of REEs are observed in sediments of the East River where granite dominates the rock type. Granite contains high concentrations of REEs and the sediments have inherited this feature from their bedrock. Alkaline element (Li, Na, K, Rb, and Cs) conce ntrations are elevated in sediments of the East River, these may reside in granitic primary minerals. Relatively high concentrations of alkaline earth elements (Mg, Ca, Sr, and Ba) are observed in the West River, inherited fr om the limestone bedrock. High Pb and Bi concentrations are found in the No rth River and are caused by Pb mineralization and the discharge of a smelte r in the upper reaches of the river. However, statistical tests did not ind icate a significant difference between Pb concentrations in the North River and the other two rivers, which suggests that statistical results should b e carefully used and explained. (C) 2001 Published by Elsevier Science Ltd.