Uptake of cadmium and lead by rice grown in four contaminated soils of Chittagong, Bangladesh

Rice was grown on soils collected from four different contaminated areas of Chittagong including city sewage, tannery, fertilizer factory and cement factory. Cadmium concentrations in grain of rice were 0.98, 0.10, 0.22 and 0.36 mg/kg-1 dry weight for city sewage, tannery, and fertilizer factory and cement factory soil, respectively. Cadmium concentration ranged from 2.73 to 6.91 mg/kg-1 in straw and 3.50 to 27.91 mg kg-1 in root. Lead concentration in grain, straw and root was significantly differed among the soils with the highest values [0.75, 4.13 and 39.37 mg kg-1, respectively] in city sewage soil and the lowest values [0.34, 2.16 and 29.53 mg kg-1, respectively] in tannery soil. Among different plant parts [root, straw and grain], the lowest values of Cd and Pb were observed in the grains. Almost all of the Cd and Pb absorbed by rice grain were likely to accumulate in the edible parts and Cd and Pb have not been detected in the grain chaffs. These results have implied that higher concentrations of Cd and Pb exceeding the maximum safe-intake levels [0.1 mg kg-1] in grains proposed by the FAO/WHO could result in human health problem

Effects of lead on growth of some vegetable crops

Pot experiments were carried out to study the effects of lead [Pb] on growth of Amaranth, Chinese Amaranth and Spinach. Six levels of Pb [0, 20, 40, 60, 80 and 100 mg kg [-1]] were used in the pot experiments. Lead application in soil significantly decreased the number of leaves plant [-1] of Amaranth, Chinese Amaranth and Spinach. Shoot height and root length of the tested vegetables crops were also significantly decreased by Pb application except for root of spinach. The present decline in shoot height at 100 mg Pb kg[-1] soil treatment as compared to the control was about 57, 75 and 47% for Amaranth, Chinese Amaranth and Spinach, respectively. The reduction of root length of Amaranth and Chinese Amaranth was 34 and 59%, respectively at the highest rate of Pb application from that of the control. In general, a gradual decrease in shoot and root biomass of all the crops with increasing rates of Pb application was observed. Shoot and root biomass of amaranth were reduced by 49 and 45% respectively with 100 mg Pb kg[-1] soil treatment over control. The corresponding reductions for Chinese Amaranth were 27 and 48% and for Spinach were 39 and 45%, respectively

Growth and accumulation of lead in amaranthus [amaranthus tricolor L.] as influenced by various levels of lead in soil

A pot experiment with six levels of lead [0, 10, 20, 30, 40 and 50 mg Pb kg[-1] soil] was conducted to study the effects of lead on the growth of Amaranthus [Amaranthus tricolor L.] and Pb accumulation in it. Plants were harvested at 30 and 45 days after sowing [DAS]. Plant height at 45 DAS was significantly different among the treatments. Lead application at 40 mg kg[-1] of soil and above significantly decreased the shoot weight at 30 DAS and root weight at 45 DAS. There was no uptake of Pb by shoot and root of Amaranthus up to 30 and 20 mg kg[-1] of Pb application, respectively both at 30 and 45 DAS At both 30 and 45 DAS, Pb concentration in shoot and root increased gradually with increasing Pb application above 30 and 20 mg kg[-1] of soil, respectively. The concentration of Pb was higher in root than shoot of Amaranthus and the Pb partitioning [shoot: root Pb concentration and amount] decreased with increasing contamination level [above 20 mg Pb kg[-1] soil]. Bioaccumulation coefficient of Pb was lower in shoot than root of Amaranthus indicating lower translocation of Pb from root to shoot

Growth and accumulation of cadmium in Amaranthus [Amaranthus tricolor L.] as influenced by various levels of cadmium in soil

A pot experiment with six levels of cadmium [0, 1, 3, 5. 7 and 9 mg kg[-1] soil] conducted to investigate the effects of cadmium on the growth of Amaranthus [Amaranthus tricolor L.] a popular leafy vegetable crop in Bangladesh, and Cd accumulation in it. Plants were harvested at 30 and 45 days after sowing [DAS]. Plant height and biomass production of shoot and root were significantly affected by Cd treatments and there was a depression of yield due to increased Cd application. Cadmium accumulation in Amaranthus and the shoot: root ratio of Cd increased with increasing Cd concentrations in soil. The increase of soil contamination level led to a decrease of bioaccumulation coefficient in shoot and root at both the stages. The capacity for Cd accumulation in edible parts of Amaranthus with the absence of any visual symptoms indicates a potential danger for human consumption