Abstract:

Soil heavy metal pollution is one of the main environmental problems in Pearl River Delta Economic Zone, which directly threatens the stability of regional ecosystem and food safety, and has profound influences on economic sustainability, especially for sustainable agriculture and people’s health. Consequently, soil environment quality and food safety in this region have receiving extensive attention from all around China. Based on multi-purpose regional geochemical survey, regional eco-geochemical assessment, local eco-geochemical assessment and comprehensive appraisal, the eco-geochemical survey and assessment in Pearl River Delta Economic Zone of 47,954 km²(including the area of 10 m depth in shallow inshore waters) was completed. Samples of soil, sediments of intertidal and major rivers in the region were collected in accordance with the two-layer grid method.Totally 71 elements and indicators for soils and sediments were determined and it is the first time to study the geochemical characteristics of the Pearl River Delta region. On the basis of the regional survey，the samples of rock, soil, sediment, dust, water, biology, human hair and other types of media samples in significant zone were systemic collected.The composition, distribution characteristics, sources, impact mechanisms and ecological security, migration and transformation process of toxic elements and nutrition elements in significant zone were investigated through case research and general analysis. According to the characteristics of the area, we firstly carried out the study of geochemical character of delta formation evolution and formulation of environmental quality standards for soils in the Pearl River Delta region.

Key words: soil, offshore sediment, geochemical characteristic, eco-geochemical assessment, Pearl River Delta Economic Zone