Environmental Toxicology of Cadmium and Lead (in the Case of Long Khang, Vietnam)

Resumo

The effects of toxic effects of cadmium and lead on vegetation are revealed. As the experimental culture selected rice, cultivated in the site Long-Khanh in Vietnam. The experimental system included the saturation of soil samples with solutions of toxic metals in 7 concentration levels. As assessment criteria are determined: growth, ramification of rice, the state of the root system, the definition of places of maximum accumulation. The patterns of toxicological effects of lead and cadmium are revealed. Concentration of Cd²⁺ 0.1 mg/kg stimulates growth, as well as ramification of rice. The concentration of Cd²⁺ ≥ 30 mg/kg inhibits plant growth. Pb²⁺ < 10 mg/kg can promote plant growth, increase plant productivity (stimulate very high branched rice, increase root length). At higher concentrations, the tillering tendency tends to decrease. Coefficients of concentrations between pollution levels and estimated state criteria were determined. They characterize the high levels of interconnections from 0.7 to 0.9. Levels of accumulation of heavy metals in parts of plants are revealed. The maximum values are determined in the branches, leaves and roots. The accumulation of Pb in ecosystems is higher than Cd.