Experimental evidence has indicated that dietary zinc level may modulate the accumulation and toxic response to lead, cadmium and mercury. Insufficient zinc intakes have been shown to increase the risk associated with the exposure of animals to these heavy metals. On the other hand, moderate zinc supplements have been found to have a marked effect in preventing the deleterious effect produced by lead, mercury and cadmium. The mechanism by which dietary zinc may influence risks from lead, cadmium and mercury is not fully understood; however, the factors involved in the absorption from the gastrointestinal tract are of considerable concern.
This study was conducted to investigate toxic effects of Pb on growth and nutrient uptake in Black gram. Black gram was subjected to seven (5, 10, 25, 50, 75, 100 & 200 kg-1) levels of lead. Due to Pb toxicity, plant growth was adversely affected and relatively a severe reduction in root biomass was recorded. The Pb accumulation increased with the increase in lead concentrations. The uptake of different nutrients, i.e., N, P, K, Ca and Mg was reduced in black gram due to the lead treatment.
The aim of this study was to assess the impact of single-walled carbon nanotubes (SWCNT) on the toxicity of cadmium (Cd) using the crustacean Daphnia magna. LC50 of Cd and SWCNT alone and combined were calculated and compared. Sorption of Cd on SWCNT was also quantified in separate batch experiments. Results showed that the maximum adsorption of Cd onto SWCNT calculated by the Langmuir equation was 24.4 mg kg-1. LC50s for Cd and SWCNT alone were 252.3 μg L-1 and 1400 μg L-1, respectively. In the presence of 500 and 1000 μg L-1 of SWCNT, Cd LC50s were 127.2 and 120.1 μg L-1 respectively. Therefore, Cd toxicity increased when organisms were exposed to both contaminants which indicated that SWCNT induces a synergistic toxic effect on the survival of D. magna. It appears that even if SWCNT had a low adsorption capacity for Cd, toxicity of the metal can be increased. Our study shows the complexity of SWCNT toxicity and how the understanding of their interactions with other contaminants is crucial to determine the consequences of their release into the environment.
This paper describes the optimization of the geometry of investigated system - L-ascorbic acid and cadmium octahedral complex. The research was carried out using semi-empirical CNDO calculations with minimization based on Polak-Ribiere conjugate gradient method. The structures have been confirmed with spectrophometric experiments.
The toxic effects of new quaternary ammonium chlorides on dicotyledonous plant Sinapis alba was evaluated. Investigated compounds differed either in hydrophobic chain length or hydrophilic part properties. The compounds used in the study are meant to be new wood preservatives because of their excellent fungicidal properties. It has been stated that the toxic effects of examined chlorides on Sinapsis alba depend on the compound structure. Alkyl(alkoxymethyl)dimethylammonium chlorides had the lowest phytotoxic properties. The presence of benzene subsituent in the compound molecule caused an increase in toxic effects of ammonium chlorides on the Sinapis alba roots.
The aim of this study was to elucidate the influence of ethanol on concentrations of lead in tissues of rats exposed to lead acetate. The experiment was made on Wistar rats. The animals were given lead acetate (500 mg 1-1 of lead) in drinking water for 6 weeks. For 4 to 5 days before the end of exposure to lead, the animals were given intragastrically 25% solution of ethanol in doses of 5 g/kg body weight, every 12 hours. After exposure to lead acetate an increased level of lead was found in all examined tissues, i.e. blood, liver, kidneys, spleen, bones. Ethanol applied together with lead caused a redistribution of lead from bones and liver to blood and kidneys.
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