Accumulation Characteristics And Consumption Hazard Of Brassica Chinensis To Cadmium And Copper

The thesis studied the effects of cadmium(Cd) and copper(Cu) on Brassica chinensis in physiology and biochemistry, as well as the accumulation and distribution of cadmium and copper in Brassica chinensis by pot experiments. The poison mechanism of cadmium and copper to Brassica chinensis was discussed. The results showed that:1. There was not obviously injuried symptoms of Brassica chinensis by cadmium or copper single polluted. But cadmium and copper added in soil caused the growth of Brassica chinensis to be blocked and slowly, the accumulation of Brassica chinensis biomass to be remarkably suppressed. The injuried symptoms of Brassica chinensis shoot were that the adult plant dwarfed, the leaf blade changed thinness and stricture, the chlorosis phenomenon was obvious, and the root system developed badly.2. The contents of chlorophyll, soluble protein, Vc and nitrate in Brassica chinensis reduced, the relative permeability of cell membrane in leaf of Brassica chinensis increased, and the activity of nitric acid reductase of Brassica chinensis decreased as the amounts of cadmium (1 mg/Kg Cd was an exception) or copper added in soil increased. When cadmium and copper added in soil together, copper coordinated cadmium to perform the effects.3. The contents of cadmium and copper increased as cadmium and copper added in soil increased. When cadmium and copper added in soil together, cadmium suppressed the absorption of Brassica chinensis to copper, copper promoted or suppressed the absorption of Brassica chinensis to cadmium was affected with their different contents pollution together.4. We can get rules that cadmium and copper translated in Brassica chinensis by studied enrichment coefficients of cadmium and copper. The order of enrichment coefficients of cadmium and copper was leaf / stem >stem / root>root / soil, the results showed that cadmium and copper easily translated once they were absorbed in root of Brassica chinensis .5. The contents of cadmium and copper of Brassica chinensis were affected by the growth time. In the forth week, the contents of cadmium of shoot of Brassica chinensis was the lowest, but in the second week, it is the highest. When cadmium and copper added in soil together, the contents of cadmium in shoot of Brassica chinensis was not only affected by the growth time but also the different contents of copper added in soil together. 6 The results showed that these were consumption hazard of cadmium and copper: nitrate contents of Brassica chinensis polluted by cadmium and copper was lower than a single treatment of copper, the consumption hazard of nitrate increased with the addition of copper; Vc contents of Brassica chinensis were reduced signigicantly because cadmium or copper or they were added in soil together, the risk of people lack Vc increased because they ate Brassica chinensis polluted by cadmium and copper. At the same growth period, the contents of cadmium and copper increased with the increasing of contents of pollution of cadmium and copper. So the risk of consumption of hazard was also increasing. The contents of cadmium and copper were higher in three weeks, but in the forth week, the contents of cadmium and copper were the lowest. So we can conclude that the consumption hazard in three weeks was the highest and at the forth week was the lowest.