Absorption of cadmium

Theory. Cadmium and zinc form negatively charged chloro-complexes which are absorbed by a strongly basic anion exchange resin, such as Duolite A113. The maximum absorption of cadmium and zinc is obtained in 0.12 M hydrochloric acid containing 100 g of sodium chloride per litre. The zinc is eluted quantitatively by a 2M sodium hydroxide solution containing 20 g of sodium chloride per litre, while the cadmium is retained on the resin. Finally, the cadmium is eluted... 

Cadmium carbonate also may be obtained by slow absorption of cadmium oxide with carbon dioxide. 

Absorption of cadmium in the gastrointestinal tract is 4-7% in adults absorption is probably higher in children. Diets low in calcium, iron, and protein enhance cadmium absorption. Zinc is an antagonist to cadmium (decreases cadmium absorption). Cadmium absorption by the lungs is dependent on particle size and the solubility of the cadmium compound, but is generally between 15% and 30%. Dermal absorption of cadmium is insignificant. 

Sarhan MJ, Roels H, Lauwerys R. 1986. Influence of manganese on the gastrointestinal absorption of cadmium in rats. J Appl Toxicol 6313-316... 

Iodide can be extracted as [(phen)3Cd"l2] ion-association pair into nitrobenzene and the atomic absorption of cadmium is measured at 228.8 nm... 

The primary routes of cadmium exposure are ingestion and inhalation with absorption of cadmium through the skin being negligible. Cigarette smoke is an important source of cadmium via inhalation. Absorption of cadmium occurs in the gastrointestinal tract (4-7% in adults) and in the lungs (15-30% in adults). 

TABLE IX Average Daily Intake and Absorption of Cadmium by Americans ... 

Selenium has been found to slightly increase the absorption of cadmium in rats (Whanger, 1981). This finding is consistent with the data of Welch and House (1980), who labeled lettuce either intrinsically or extrinsically with and Se and fed it to rats as a single meal. 

C) The results of any biological or other testing or related evaluations that directly assess the employee s absorption of cadmium ... 

Engstrom B, Nordberg G (1978) Effects of milk diet on gastrointestinal absorption of cadmium in adult mice. Toxicology 9 195-203 Forbes GB, Reina JC (1972) Effect of age on gastrointestinal absorption (Fe, Sr, Pb) in the rat. J. Nutr. 102 647-652... 

Roels H, Buchet JP, True J, Croquet F, Lauwerys R (1982a) The possible role of direct ingestion on the overall absorption of cadmium or arsenic in workers exposed to CdO or AS2O3 dust. Am. J. Ind. Med. 3 53-65... 

In humans, intestinal absorption of cadmium is estimated at 5% (McLellan et al. 1978 Friberg et al. 1986). Both human and animal data demonstrate that cadmium absorption from the lungs is 25%-50% (Friberg et al. 1986). Others report that up to 90% of cadmium deposited deep in the lung can be absorbed and distributed to other critical organs such as liver, kidney, and testis (Oberdorster 1986 Waalkes and Oberdorster 1990). 

The major route of excretion of cadmium is via feces and bile. Approximately 95% of oral cadmium dose is excreted in the feces due to the poor absorption of cadmium from the GI tract. Urinary excretion of cadmium may become significant after the onset of renal damage. 

Discussion. Turner and Miles have published the ultraviolet spectra of ferric ion and its first hydrolysis product in aqueous solution. Chatterjee made a spectrophotometric study of copper chelates. The ultraviolet absorption of cadmium was studied by Wadelin and Mellon Johnson and Andersen discussed the ultraviolet spectra of tellurium soils. 

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