US EPA

1033596 

Journal Article 

Toxicity of the arsenical herbicide monosodium acid methanearsonate in cattle 

Dickinson, JO 

1972 

Yes 

American Journal of Veterinary Research
ISSN: 0002-9645
EISSN: 1943-5681 

NIOSH/00160987 

33 

9 

1889-1892 

English 

5053169 

The toxicity and tissue distribution of monosodium-acid-methanearsonate (2163806) (MSMA) were studied in cattle. Two preparations of MSMA were used: 44.9 percent in an aqueous solution plus dye, and 59 percent in an aqueous solution. Groups of cattle received daily oral doses of 10 milligrams per kilogram (mg/kg) MSMA for 8 or 10 days, or were untreated. Some cattle were sacrificed and necropsied. Hair and tissue samples were assayed for arsenic (7440382) content. Cattle given 44.9 percent MSMA for 10 days developed severe diarrhea, dehydration, and weight loss by day 7; one steer died on day 10, one was sacrificed on day 12, and the third recovered. Cattle given 59 percent MSMA for 8 days developed severe diarrhea by day 5, and died on days 8 or 16. Both groups of treated cattle had gross and microscopic pathologic changes in the kidney and abomasum. Kidneys were swollen; on cut surfaces, the medulla was darkened and hemorrhagic, with little change in the cortex. There was hemorrhagic gastritis with mucosal erosion and ulceration, and intense hyperemia. The liver had a midzonal distribution of multiple foci of coagulative necrosis. Toxic nephrosis was or would have been the cause of death. Renal arsenic was 46 to 64 parts per million (ppm) in cattle that died during treatment, and 4 to 23ppm in those that died later; hepatic arsenic was 17 to 27ppm and 2 to 30ppm in those respective groups. Control levels were about 1ppm. The author concludes that 100mg/kg is a fatal dose of MSMA; clinical signs of poisoning were evident with 50 to 70mg/kg. The two preparations had similar effects. 

DCN-149283; Herbicides; Livestock; Toxic effects; Toxic dose; Acute toxicity; Monitoring systems; Pesticides and agricultural chemicals; Pesticides; Tissue distribution; Chronic toxicity