Public health hazards associated with arsenic poisoning in cattle
Selby, L.A.; Case, A.A.; Dorn, C.R.; Wagstaff, D.J.
Journal of the American Veterinary Medical Association 165(11): 1010-1014
1974
ISSN/ISBN: 0003-1488 PMID: 4443307 Document Number: 78849
Arsenic poisoning is usually a severe acute disease; affected animals would probably not be accepted at a slaughter-house. In cattle 7.5 mg/kg sodium arsenite causes poisoning (sheep tolerate up to 11 mg/kg) but, if percutaneous absorption occurs, the toxic dose is as low as 0.75 mg/kg. Arsenites (trivalent) are more toxic than arsenates (pentavalent). Arsenic is stored mainly in liver, kidney, and spleen, and most of it is excreted in urine though, if the salt is not readily absorbed, much of it is eliminated in the faeces. Arsenic is ubiquitous in plants, but surface deposits in soil are not common in nature: high uptakes by plants usually follow artificial contamination. Average soil content is about 5 ppm-generally as arsenopyrite. Because their dangers are now known, lead and calcium arsenic insecticides and wood preservatives are rarely used, but a derivative of phenylarsonic acid is used as a growth stimulant. In two outbreaks of poisoning which are quoted as examples, the sources of arsenic were materials discarded by a filling station (exact source never found) and spraying with weedkiller which contained 40% sodium arsenite. Cattle which survive a single exposure to arsenic should not be slaughtered for 2 weeks and, when they have been poisoned over a longer period, a 6-week interval before slaughter is desirable.