Abstract: The study showed that the adsorbed cadmium in soil could be dissolved in water,and the lower the soil pH,the higher and stronger the dissolving rate and mobility,and the more uptake by crops.The water-soluble,exchangeable and complexed cadmium contents in the contaminated soil were lower when the soil was chemically neutral,with the values being 0.68%,12.70% and 12.40%,respectively,while the insoluble (granulated) cadmium content was 74.40%.Radish caudex in the contaminated soil could absorb cadmium,and be considered as the hyperaccumulator of soil cadmium.

Key words: Pearl River Estuary, Lingdingyang Bay, meiobenthos, abundance, biomass