Elimination of an intake by sweet pepper fruits of cadmuim using various blocking systems

The possibilities of eliminating an intake by sweet pepper fruits of cadmium using different blocking systems were investigated in the period 1997-1999. Two systems of Cd blocking in soil were used: 1) incorporation of the bacteria Desulfovibrio desulfuricans in contaminated soil before planting sweet pepper seedlings (TK-B and TK-BR treatments) and 2) an increase in soil pH value (pH=7.5) by sodium hydroxide (NaOH) solution. The sweet pepper variety Slovakia planted in pots was used for the trial. The soil in pots was fertilized by NPK fertilizers and contaminated by cadmium. Yield quantity and quality of sweet pepper (content of ascorbic acid, nitrate and cadmium in fruits) were investigated. The highest yield was observed for the treatment with the bacteria Desulfovibrio desulfuricans. Based on the yields obtained for different treatments, sulfur bacteria were found to have a positive influence both on the quality and quantity of yields. There were statistically significant differences in yield quantity between the control and the treatment with bacteria. No significant differences in yield quantity were detected between other treatments. High significant differences in vitamin C content were found between years as well treatments. Nitrate content of sweet pepper fruits was far from reaching the limits defined for fruit vegetable species. It means that sweet pepper is among vegetable species with a low accumulation ability of nitrates. The addition of the bacteria Desulfovibrio desulfuricans to cadmium-contaminated soils resulted in a decrease in cadmium content of fruits by 38.66%. The application of water diluted bacteria and an increase of soil pH to a 7.5 value caused a cadmium reduction by 24.85% and 25.06% respectively as compared with the control. Analysis of variance revealed significant differences in cadmium content between treatments. The results obtained indicated that the sulfuric bacteria Desulfovibrio desulfuricans are capable of blocking cadmium and other heavy metals and can be one of methods for preventing Cd intake by vegetable fruits, which results in higher production quality