Plants uptake of cadmium

Street J.J., Lindsay W.L., Sabey B.R. Solubility and plant uptake of cadmium in soils amended with cadmium and sewage sludge. J Environ Qual 1977 6 72-77. 

Y. Guo, E. George, and H. Marschner, Contribution of an arbuscular mycorrhizal fungus to the uptake of cadmium and nickel in bean and maize plants. Plant and Soil 7774 195 (1996). 

The CLEA cadmium soil guideline value (SGV) for residential land use (without plant uptake) of 30 mg/kg is the criterion being used to assess the samples. 

Jinzu Valley, Japan. One of the most infamous cases of contaminated land and health occurred in Japan and the effects were most prominent immediately after the Second World War. Around the end of the 19th century, soils in the Jinzu River basin, part of the Toyama prefecture, became contaminated with cadmium as a result of activities upstream at the Kamioka mines. The main activity at this mine was the mining and processing of zinc (cadmium is often associated with zinc ores) with the result that wastewater rich in heavy metals was discharged into the Jinzu River. Contaminants from this industry moved down-stream and caused contamination of soils in paddy fields as a result of abstraction of river water into fields in order to cultivate the local rice crop. Under favourable conditions, cadmium can be a fairly mobile heavy metal, particularly in soils with low pH, and increases in soil cadmium can often result in an increase in the uptake of cadmium by plants. This in turn results in an increase in dietary exposure and the consumption of contaminated agricultural crops can be a major pathway of human exposure. 

Hovmand me, Tjell JC and Mosbagk H (1983) Plant uptake of airborne cadmium. Environ Pollut 30 27-38. 

Increases in soil cadmium content result in an increase in the uptake of cadmium by plants. The uptake by plants from soil is greater at low soil pH. Processes that acidify soil (e.g. acid rain) may therefore increase the average cadmium concentrations in foodstuffs (WHO, 1992b). 

The effects of soil contamination with potentially toxic trace elements on plant composition has attracted a great deal of attention from research workers in recent years and there has also been an increase in interest in the relationship between plant uptake and the concentration of particularly toxic elements, such as cadmium, in soil solutions. For example, Lagerwerff [297] has reported work on the uptake of cadmium, lead and zinc by radishes from the soil and... 

Cadmium is commonly present in sewage sludges, sometimes in quite high concentrations of the order of 100 ppm in the dry matter. Since this material is now being actively promoted as a fertiliser in the interests of disposal, it seems inevitable that there will be increases in the concentration of this metal in food marketed for human consumption as a result of cadmium contamination of agricultural soils. It is already clear that the uptake of cadmium by plants... 

Cadmium contents in tree specimens (leaves, needles) from various regions display higher concentrations at an agricultural site than in an urban industrialized area. Since the plant uptake of this element essentially takes place via the roots, it must be assumed that the different contents depend on the bioavailability or mobility of this heavy metal in the soil. 

John, R., Ahmad, P., Gadgil, K., and Sharma, S., Effect of cadmium and lead on growth, biochemical parameters and uptake in Lemna polyrrhiza L., Plant Soil and Environment, 54 (6), 262-270, 2008. 

Jung J., Logan T.J. Effects of sewage sludge cadmium concentration on chemical extractability and plant uptake. J Environ Qual 1992 21 73-81. 

Singh B.R., Almas A., Jeng A.S., Narwal R.P. Crop uptake and extractability of cadmium in soils naturally high in metals at different pH levels. Commun Soil Sci Plant Anal 1996 26 2123-2142. 

Bjerre, G.K. and H.H. Schierup. 1985. Uptake of six heavy metals by oat as influenced by soil type and additions of cadmium, lead, zinc and copper. Plant Soil 88 57-69. 

Phosphate fertilisers also contain a number of other elements found in the parent phosphate rock (Bowen, 1979 Bockman et al., 1990 Jackson and Alloway, 1992). Cadmium originating from sedimentary rock is particularly undesirable, and processes for the removal of Cd from such fertilisers are being developed (Bockman et al., 1990). Fertilised soils have shown increases in Cd content after a number of years, but there appears to be little evidence for long-term Cd-increase in crop plants, except possibly for wheat (Jones and Johnston, 1989). Mortvedt (1984) determined the uptake of Cd and Zn by several vegetable crops heavily fertilised with triple superphosphate over a ten year period. Cd levels were found to be similar in fertilised and unfertilised snap bean seed, beet blades and roots, and in sweet corn leaves and grain. However, Zn concentrations were found to decrease with P application in all tissues except cabbage heads and cores. Claims that fertilisers promote the uptake of Al by plants have been refuted (Akerstrand et al., 1988). 

John, M. K., Van Laerhover, J., and Chauh, H. H. (1972). Factors affecting plant uptake and phytotoxicity of cadmium added to soils. Environ. Sci. Technol. 6, 1005—1009. 

Koeppe, D.E. 1977. The uptake, distribution, and effect of cadmium and lead in plants. Sci. Total Environ. 7 197-206. 

Some of the effects of toxic chemical mixtures on soil pollution are predictable. Acidic soils dissolve otherwise insoluble metal oxides and salts, thereby increasing available metal concentrations and toxicity to flora and fauna. Available copper content is inversely proportional to increased pH of soiU4 Earthworm mortality in soil polluted by lead increases as pH decreases. I15l The addition of ethylenediaminetetraacetic acid (EDTA) and its disodium salt to soil contaminated with cadmium, lead, and zinc increases the availability of these metals to plants and results in significant increases in the uptake of these in plants. I25l... 

Even when considered on a long term basis, there is considerable doubt that the presence of land filled battery metals such as lead, zinc, and cadmium would have the catastrophic environmental effects which some have predicted. Studies on 2000-year old Roman artifacts in the United Kingdom (Thornton 1995) have shown that zinc, lead and cadmium diffuse only very short distances in soils, depending on soil type, soil pH and other site-specific factors, even after burial for periods up to 1900 years. Another study in Japan (Oda 1990) examined nickel-cadmium batteries buried in Japanese soils to detect any diffusion of nickel or cadmium from the battery. None has been detected after almost 20 years exposure. Further, it is unclear given the chemical complexation behavior of the metallie ions of many battery metals exactly how they would behave even if metallic ions were released. Some studies have suggested, for example, that both lead and cadmium exhibit a marked tendency to complex in sediments and be unavailable for plant or animal uptake. In addition, plant and animal uptake of metals such as zinc, lead and cadmium has been found to depend very much on the presence of other elements such as iron and on dissolved organic matter (Cook and Morrow 1995). Until these behavior are better understood, it is unjustified to equate the mere presence of a hazardous material in a battery with the true risk associated with that battery. Unfortunately, this is exactly the method which has been too often adopted in comparison of battery systems, so that the true risks remain largely obscured. 

However, the uptake from soil is limited. Plants in locations with high-level exposure to cadmium (in the range of hundreds of mg/kg), have growth reduction as the major effect. Plants exposed to cadmium in the field for long periods can develop tolerance to the metal (WHO, 1992a). 

Florijn, P.J., Van Beusichem, M.L., 1993. Uptake and distribution of cadmium in maize inbred lines. Plant Soil 150, 25-32. 

---