Cadmium dredged material

The possibilities of disposal of these enormous quantities of material are severely limited because of the pollutants present in the dredged material. An example is given in Figure 7-1 In the Rotterdam harbor -which will be presented as a case study in section 7.4 - the amount which has to be dredged annually increased from less than 1 Million m in 1920 to approximately 23 Million m in the 1980 s. In the last 80 years the cadmium concentrations increased by a factor of approx, 100... 

Pot experiments and field studies on dredged materials from Rotterdam harbour that in particular cadmium concentrations approximate or exceed the tolerable level in several crops. In green leafy vegetables, wheat grain and other cereals, and in most green fodder crops, the cadmium concentrations must be considered too high for human and animal consumption. 

Pore water data from dredged material obtained at Hamburg indicate typical differences in the kinetics of proton release from organic and sulfidic sources (Table 8.1). Recent deposits are characterized by low concentrations of nitrate, cadmium and zinc when these low-buffered sediments are oxidized during a time period of a few months to years, the concentrations of... 

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