Transfer of Inorganic Mercury to Milk of Goats

Metabolism of mercury, administered as methylmercuric chloride or mercuric chloride, by lactating ruminants

“…Clarkson (1971) reported that less than 2% of the Hg given as HgCl2 was absorbed by mice. Similarly, Howe et al (1972) and Potter et al (1972) found that the HgCl2 form of Hg was very poorly absorbed by goats and cows, respectively. Data obtained in the research reported here also showed that the goat apparently absorbed less than 20% of the Hg given as HgCl2 in nine successive daily oral doses.…”

“…Potter et al (1972) reported a cumulative secretion of 0.01% of a single oral dose of Hg from HgCl2 in milk of cows during a 6-day post-treatment period. Similarly, Howe et al (1972) found that goats given 203HgCl2 orally secreted less than 0.02% of the dose in milk during a 16-day post-treatment period. Neathery et al (1974) presented data showing that only 0.17% of the Hg given orally as CHgHgCl was found in milk over a 14-day interval after treatment.…”

“…Information on this point is meager. Howe et al (1972) and Potter et al (1972) presented evidence that little radioactive Hg appeared in goat's and cow's milk following the oral administration of single doses of 203Hg-labeled mercuric chloride. Neathery et al (1974) reported similar observations following treatment of cows with a single oral dose of 203Hg-labeled methylmercuric chloride.…”

Transformation of mercuric chloride and methylmercury by the rumen microflora

“…Studies using goats, calves, and milk cows as test animals have demonstrated that with single oral doses of CH3HgCl, 59 to 80% is absorbed from the digestive tract (21,27). In studies with single oral doses of HgCl2 in goats, 86 to 99% of the total dose was excreted in the feces (15,27). Those data clearly show that CH3Hg' is readily absorbed from the digestive tract, whereas Hg2+ is not.…”

Interaction of Mercury with Human and Bovine Milk Proteins

“…It is well-known that exposure to this metal during lactation may cause adverse effects in the development of infants due to the transfer that occurs from the mother to child through breast milk, especially in populations with a diet based on fish products.1) This has been supported by the fact that high levels of mercury have been found in the blood and hair of infants exposed to this metal only through breast milk.l 3) In ruminants, it has been found that mercury present in milk represented only 10% of that present in blood. 4 ) Despite this relatively low transfer of mercury from blood to milk, it must be taken into account that bovine milk and dairy products are the most important food in the diet for children.…”