Accumulation and Depletion of Cadmium and Lead in Tissues and Milk of Lactating Cows Fed Small Amounts of These Metals

Abstract

Groups of lactating cows were fed 0, 40, and 200 mg of added cadmium (as chloride) and 0, 100, and 500 mg of added lead (as acetate) per animal per day in separate experiments. Milk and blood were sampled periodically and analyzed for concentrations of metal ions. Metal feeding was discontinued after 3 mo, and selected animals were necropsied for tissue residue studies. Remaining animals were continued on control ration for another 3 mo and then killed and tissues obtained. Cadmium feeding did not produce a dose-related increase of this metal in blood, milk, or skeletal muscle. Liver and kidneys were the primary organs of cadmium accumulation, and concentration of cadmium in these organs continued to rise during 3 mo of feeding the control diet after the initial exposure period. Lead did not accumulate in skeletal muscle but showed a dose-related increase in blood, milk, bone, liver, and kidney. In most tissues there was a rapid decline of lead concentrations after cessation of treatment, except in bone. Low dietary intake of cadmium and lead do not produce an appreciable rise of these metals in edible products, e.g., milk or meat. Of the tissues analyzed, liver and kidney accumulate both cadmium and lead, and cadmium especially persists in these organs for long periods. Bone is the primary site of deposition for lead but not cadmium.

Review of Russian language studies on radionuclide behaviour in agricultural animals: 3. Transfer to muscle

“…The most reliable data referred to by Ng et al is the stable data of Nelmes et al (1974) which gives an F f of 7 Â 10 À4 d kg À1 . Other relevant F f values are those for stable lead reported by Sharma et al (1982) (3.5 Â 10 À4 d kg À1 ) and Vreman et al (1986) (2 Â 10 À4 d kg À1 -1.02 Â 10 À3 d kg À1 ) which are also consistent with the data in Table 5. These last three sources provide the data for the revised IAEA value of 7.0 Â 10 À4 d kg À1 (Howard et al, submitted for publication).…”

Stable Lead in Milk and Derivates

“…Due to the elevated toxicity of lead to human beings, even at a trace level, the world sanitary authorities established limits of concentration of this metal in milk since the consumption of these foodstuffs via ingestion of the element by human is considered important (Sharma et al 1982). In Brazil, the Ministry of Health reviewed the tolerance levels of lead in foodstuffs and lowered the acceptability levels of lead in the majority of alimentary products.…”

Effects of excess dietary selenite on lead toxicity in sheep

“…Selenium was determined fluorometrically (6) and Pb was determined by flameless atomic absorption using the method of standard 67 additions (7). A national Bureau of Standards (NBS) bovine liver sample was analyzed with each set of Pb samples.…”