Growth and Cadmium Accumulation of Plants Grown on a Soil Treated with a Cadmium‐Enriched Sewage Sludge

Abstract

Corn, wheat, rice, field bean, soybean, cabbage, spinach, lettuce, curlycress, carrot, turnip, radish, tomato, and squash plants were grown to commercial harvest stage using as the substrate, soil pre‐treated with a municipal sewage sludge (1%) containing variable amounts of CdSO4 up to 640 µg Cd/g soil. Observations included injury symptoms, yield decrement, Cd level of diagnostic tissue, and Cd and Zn content of harvested produce. Cadmium‐sensitive plants such as spinach, soybean, curlycress, and lettuce were injured by soil Cd levels of 4–13 µg Cd/g soil; whereas, tomato and cabbage tolerated soil levels of approximately 170 µg Cd/g soil without exhibiting injury symptoms. Rice was tolerant at all levels tested. Leafy plants such as lettuce, spinach, and turnip greens (tops) accumulated 175 to 354 µg Cd/g; whereas, fruit and seed tissue of plants under comparable treatment, with the exception of soybean, accumulated no more than 10 to 15 µg Cd/g tissue. The concentrations for soybean extended up to 30 µg Cd/g tissue. Paddy rice exhibited no ill effects for soil Cd treatments up to 640 µg Cd/g soil. Grain of plants under the 640 µg Cd/g treatment contained 2 µg Cd/g tissue. DPTA‐extractable Cd correlated (r=0.99) with the level of CdSO4 added to the substrate.

Cadmium accumulation in crops

“…Soil studies on contaminated soils showed lettuce, spinach, celery and cabbage tended to accumulate relatively high concentrations of Cd, while potato tubers, corn, french beans and peas accumulated lower amounts of Cd (Davis and Carlton-Smith 1980). Spinach and lettuce also accumulated high Cd levels on soils with sludge application, while Cd concentrations were medium in radish and soybean and low in corn and rice (Bingham et al 1975). In sludge-treated soils, Cd concentration of tomato was higher than that of barley or beans (Bradford et al 1975).…”

“…Cadmium accumulation and distribution in plants differ with species and among cultivars within a species (Page et al 1972;Bingham et al 1975;Pettersson 1977;Chang et al 1982;Kuboi et al 1986;Yang et al 1995). Cadmium concentration of plants grown in solution culture increased in the order: oats, wheat < bean, pea, sunflower, cucumber < corn, mustard < radish, kale, rape < tomato, carrot, sorrel < lettuce (Pettersson 1977).…”

“…Although plants do not require Cd for growth or reproduction, the bioaccumulation index of Cd in green plants exceeds that of all other trace elements (Kabata-Pendias and Pendias 1992). Plants can accumulate relatively high levels of cadmium, without adverse effects on growth (Bingham et al 1975;Bingham 1979;Kuboi et al 1986). Cadmium is retained for many years in the human body, so consumption of foods high in Cd may induce chronic toxicity (Jackson and Alloway 1992;FAO/WHO 1995).…”

Is the bioavailability index applicable for trace elements in different types of soil?

“…Randall et al (1976) concluded that DTPA could be used successfully to determine the available Mn in low organic matter soil. Bingham et al (1975) showed a highly significant correlation between DTPA-extractable Cd and that taken up by corn. Singh and Narwal (1984) found numerically superior correlation coefficients between Cd, Pb and Zn extracted by DTPA and the total uptake of these metals by rape *The extractable trace elements (C E ) are expressed in percentage of the total content of the elements in the untreated soil and plant accumulation reduction of the elements in plant (⌬C P ) and in root (⌬C R ) are expressed in percentage of the total plant content of the elements in the untreated soil.…”

Impact of textile sludge on the growth of red amaranth (Amaranthus gangeticus)

“…Metals' solubility changes reversely with soil pH, i.e., metal solubility increases with decrease in soil pH and, as a result, metal uptake by plants in calcareous soils is higher than plants in acidic soils (Fisseha 2002). Bingham et al (1975) found that Cd accumulation was lower in shoots of cereals and legumes than leafy vegetables such as curly cress, lettuce and spinach. All of these factors are very important to do further study in these fields.…”