A Regional‐Scale Study on the Crop Uptake of Cadmium from Sandy Soils

Abstract

Plant uptake is one of the major pathways by which cadmium (Cd) in soils enters the human food chain. This study was conducted to investigate the uptake of Cd by crops from soils within the wastewater irrigation area (WIA) of Braunschweig (Germany) and to develop a simple process-oriented model that is suited to predict Cd uptake at the regional scale. The sandy soils within the WIA (4300 ha) have received considerable loads of heavy metals by irrigation using municipal wastewater for up to 40 years. In 1998 and 1999, we sampled soil and plant material at 40 potato (Solanum tuberosum L.), 40 sugar beet (Beta vulgaris L.), and 32 winter wheat (Triticum aestivum L.) fields. In both years and for all three crops, we found close linear relationships between the Cd content of plant material and the Cd concentration in soil solution. For all three crops, we observed a trend of relatively increased Cd uptake in the year with the higher saturation deficit of the atmosphere. We interpret this to indicate that transpiration plays an important role in the Cd uptake of crops under the conditions of the WIA. In modeling the uptake of Cd by crops, we assume that uptake is proportional to mass flow, that is, the product of water transpired, Cd concentration in soil solution, and a plant-specific empirical parameter. The simulations agreed well with the observed Cd contents in crops. Our model explained between 66 and 87% of the observed variance.

Cadmium in plants on polluted soils: Effects of soil factors, hyperaccumulation, and amendments

“…But the fact that the concentration of Cd in the leaves and roots fell by about half indicates that the available amount of Cd in the soil decreased with time, even though the total amount hardly changed. In a long-term wastewater disposal site (40 years) on a sandy soil in Germany, still in use, there was a linear relationship between Cd content of potato (Solanum tuberosum), sugar beet (Beta vulgaris), and winter wheat (Triticum aestivum) and the Cd concentration in the soil solution (Ingwersen and Streck, 2005; Table 1). Comparison between the studies of Granato et al (2004) and Ingwersen and Streck (2005) cannot be made, because in one study (Granato et al, 2004), total Cd in the soil was studied, and in the other (Ingwersen and Streck, 2005), Cd in solution was studied.…”

“…Table 1 shows studies in which the Cd concentration has been given in both the soil and the plant. Soils have been polluted with Cd by application of sludge Granato et al, 2004;Adams et al, 2004) or wastewater (Xiong et al, 2004;Ingwersen and Streck, 2005); by being near a smelter (Brown et al, 2004;Sappin-Didier et al, 2005) or by having Cd salts added to the soil (Jiang et al, 2003;Kuo et al, 2004;Turgut et al, 2004;Evangelou et al, 2004;Dechamps et al, 2005;Li et al, 2005;Treder and Cieslinski, 2005;Patel et al, 2005;). The only study in Table 1 that reports Cd naturally in the soil is in the one by Tsadilas et al (2005), who grew tobacco with no added Cd.…”

Differential cadmium stress tolerance in five Indian mustard (Brassica junceaL.) cultivars

“…36 It has also been reported that Cd accumulation by plants grown in soil is directly related to transpiration and thereby to stomatal conductance. 19,37 Further, the ability of plants to grow on Cd contaminated soils is generally correlated with the ability of roots to exclude Cd from the plant and/or of plant tissues to chelate Cd as a non-toxic compound or sequester it in a non-vital cellular compartment. 6,38 Exposure to heavy metals results in the excessive production of ROS in plants.…”

Nanoparticulate Zeolitic Tuff for Immobilizing Heavy Metals in Soil: Preparation and Characterization

“…Uptake of Cd by plants depends on several plant and soil factors such as solution-phase concentration, pH, and organic carbon content. Moreover, the environmental conditions (temperature and saturation deficit) may play an important role in controlling Cd uptake (Ingwersen and Streck 2005). Anthropogenic contamination of soils by heavy metals (Cd, Pb, and Zn) occurs from many sources such as mining, atmospheric deposition from smelting operations, application of sludge, and mineral fertilizers and pesticides (Alloway 1995).…”