Bioavailability cadmium

Voets, J. Bervoets, L. Blust, R. Cadmium Bioavailability and Accumulation in the Presence of Humic Acid to the Zebra Mussel, Dreissena polymorpha. Environ. Sci. Technol. 2004, 38, 1003-1008. 

Modifying lead, zinc and cadmium bioavailability in soil by apatite and EDTA addition. Frese-nius Environmental Bulletin, 10, 727-730. 

Carlson, A.R., Phipps, G.L., Mattson, V.R., Kosnian, P.A. and Cotter, A.M. (1991) The role of acid-volatile sulfide in determining cadmium bioavailability and toxicity in freshwater sediments. Environ. Toxicol. Chem., 10, 1309-1319. 

Lock, K., Janssen, C.R. and de Coen, W.M. (2000) Multivariate test designs to asses the influence of zinc and cadmium bioavailability in soils on the toxicity to Enchytraeus albidus. Environmental Toxicology and Chemistry, 19, 2666 - 2671. 

As is the case with assessments of the toxicity of dissolved trace metals, the development of sediment quality criteria (SQC) must be based on the fraction of sediment-associated metal that is bioavailable. Bulk sediments consist of a variety of phases including sediment solids in the silt and clay size fractions, and sediment pore water. Swartz et al. (1985) demonstrated that the bioavailable fraction of cadmium in sediments is correlated with interstitial water cadmium concentrations. More recent work (e.g., Di Toro et al, 1990 Allen et al., 1993 Hansen et al, 1996 Ankley et ai, 1996, and references therein) has demonstrated that the interstitial water concentrations of a suite of trace metals is regulated by an extractable fraction of iron sulfides. 

Other studies use soil or sediment samples for a more accurate indication of microbial activity in natural environments. In these samples, organic matter and clay particles play a role in metal toxicity.76112113 Both organic material and clay particles in soil can bind metals and reduce their bioavailability. For example, Pardue et al.87 demonstrated that much less solution-phase cadmium was required to inhibit trichloroaniline (TCA) dechlorination in a mineral-based soil than in a soil containing a higher concentration of organic matter. Other studies have shown that adding clay minerals to a medium mitigates toxicity. Clay minerals, such as kaolinite, montmorillonite, bentonite, and vermiculite, can bind to metals to decrease the amount that is bioavailable.112 115... 

Free, ionic species of metals are at their highest concentrations at lower pH, so metals tend to be more bioavailable under these conditions.121128 At acidic pH, more protons are available to saturate metal-binding sites.99 For example, metals are less likely to form insoluble precipitates with phosphates when the pH of the system is lowered because much of the phosphate has been protonated. Under basic conditions, metal ions can replace protons to form other species, such as hydroxo-metal complexes. Some of the hydroxo-metal complexes are soluble, such as those formed with cadmium, nickel, and zinc, whereas those formed with chromium and iron are insoluble. 

Piol, M.N., L6pez, A.G., Mino, L.A., Afonso, M.D.S., and Guerrero, N.R.V., The impact of particle-bound cadmium on bioavailability and bioaccumulation A pragmatic approach, Environ Sci Technol,... 

Pierzynski GM, Schwab AP. 1993. Bioavailability of zinc, cadmium, and lead in a metal contaminated alluvial soil. J Environ Qual 22 247-254. 

Most trace metals may be precipitated with phosphate into insoluble metal phosphates (Table 7.5). Most metal phosphates have low solubility. High localization of phosphates reduces the bioavailability of Zn in arid soils. The banded application of P near the seeds depresses Zn uptake by com (Adriano and Murphy, 1970 Grant and Bailey, 1993), causing Zn deficiency. However, both N and P fertilizers increase Cd concentration in plants. Cadmium and Zn are antagonistic in root uptake and distribution within plants. 

Megharaj K.V.M., Sethunathan N., Naidu R. Bioavailability and toxicity of cadmium to microorganisms and their activities in soil a review. Adv Environ Res 2003 8 121-135. 

This author reviews the limitations of ASV and differential pulse polarography in determining trace metal speciations, and thereby bioavailability and transport properties of trace metals in natural waters. In particular, it is stressed that nonuniform distribution of metal-ligand species within the polarographic cell represents another limitation inherent in electrochemical measurement of speciation. Examples relate to the differential pulse polarographic behaviour of cadmium complexes of NTA and EDTA in seawater. 

To protect humans and other mammals, proposed air-quality criteria range from 0.01 to less than 1.0 mg/m3 for metallic nickel and slightly soluble nickel compounds, 0.015-0.5 mg/m3 for water soluble nickel compounds, and 0.005 to 0.7 mg/m3 for nickel carbonyl (Table 6.10). Inhalation of nickel subsulfide concentrations (0.11 to 1.8 mg Ni/m3) near the current threshold limit value of 1 mg Ni/m3 can produce detrimental changes in the respiratory tract of rats after only a few days of exposure (Benson et al. 1995). Additional animal studies are recommended to identify minimally effective inhalation exposure levels for the various nickel compounds (USPHS 1993). Continued monitoring of nickel refining, nickel-cadmium battery manufacture, and nickel powder metallurgy installations is recommended because ambient air levels of bioavailable nickel at these... 

Heavy metals in the environment, especially their accumulation in soils, is a serious environmental problem which the whole world faces (Du et al. 2005). The farmland soils are an important media of the ecological cycle of Cadmium, and its harm to human health can t be neglected (Wu et al. 2004). Heavy metal migration, transformation and toxicity to plants in soil are directly influenced by the quantity proportions of various forms (Zhu et al. 2002). The toxicity of water-extractable and adsorbed and exchangeable metals are the greatest, and residual metals is the lowest (Liu etal. 2002). Different forms have different bioavailability thus their influences on the environment and human health are different. It is critical to have a good understanding of Cadmium forms in soil. This paper describes the Cadmium forms in the acid soils of eastern China. 

Zhu Bo, Qing Changle, Mu Shusen. 2002. Bioavailability of exotic zinc and cadmium in purple soil. Chinese Journal of Applied Ecology, 13(5), 555-558 (in Chinese with English abstract). 

Effects of Water Chemistry on Bioavailability and Toxicity of Waterborne Cadmium, Copper, Nickel, Lead, and Zinc on Freshwater Organism Meyer, Clearwater, Doser, Rogaczewski, Hansen 2007... 

Ankley GT, Phipps GL, Leonard EN, et al. 1991. Acid-volatile sulfide as a factor mediating cadmium and nickel bioavailability in contaminated sediments. Environmental Toxicology and Chemistry 10 1299-1307. 

The cadmium pigments (cadmium-/zinc sulfide and cadmium sulfide/-selenide) are exempted from labelling. The cadmium pigments are slightly soluble in diluted acids and the soluble cadmium is bioavailable. Therefore some cadmium pigment producers are labelling their cadmium-/zinc sulfide and cadmium sulfide/-selenide pigments like the cadmium compounds. 

Besser, J.M., Brumbaugh, W.G., May, T.W. and Ingersoll, C.G. (2003) Effects of organic amendments on the toxicity and bioavailability of cadmium and copper in spiked formulated sediments, Environmental Toxicology and Chemistry 22 (4), 805-815. 

Erten-Unal, M., Wixson, B.G., Gale, N. and Pitt, J.L. (1998) Evaluation of toxicity, bioavailability and speciation of lead, zinc and cadmium in mine/mill wastewaters, Chemical Speciation and... 

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