TABLE IV-11. Suggested Maximum Allowable 



Concentrations of Certain Inorganic Elements 



in Farm Animals' Water Supply 



Substance 



Suggested maximum 



allowable 

 concentration, mg/i 



Arsenic 0.05 



Cadmium 0.01 



Chromium (hexavalent) 0.05 



Lead 0.05 



Selenium 0.01 



satisfactory for farm use and presumably safe for 

 livestock. Further data on specific mineral salts 

 are listed in the subsequent discussions. 



Antimony may find its way into water supplies 

 as antimony potassium tartrate, or "tartar emetic", 

 since this is sometimes used as a mordant in tex- 

 tile and leather manufacturing {110) and for the 

 control of ants and other insects. The minimum 

 lethal oral dose of this compound for rats is listed 

 at 300 mg/kg body weight, however, horses can 

 apparently take 5.8 g and cattle 3.8 g three times 

 daily without harm {124). 



Arsenic has long enjoyed notoriety as a poison, 

 but more recently, arsenicals have found some 

 usefulness in livestock production mainly as a 

 coccidiostat in poultry feeding or in "dip" solu- 

 tions for animals. There is also recent evidence 

 that arsenic functions in some way to reduce selen- 

 ium toxicity when present in drinking water at 

 levels of 5 mg/1 as sodium arsenate {36). The 

 toxicity of arsenic depends to a considerable ex- 

 tent upon the form in which it occurs. Thus, LD50 

 doses for female rats are 112 mg/kg as elemental 

 arsenic or 298 mg/kg as calcium arsenate {60). 

 Wadsworth {185) has listed toxic dose ranges for 

 arsenic as shown in table IV-12. 



TABLE IV-12. Proposed Toxic Dose Ranges 

 for Arsenic (185) 



Animal 



Toxic dose of As, 

 g/animal 



Poultry 0.05- 0.10 



Dogs 0.10- 0.20 



Swine 0.50- 1.00 



Sheep, goats, horses 10.00-15.00 



Cattle 15.00-30.00 



Beryllium is a rare element unlikely to occur in 

 natural waters, although it could conceivably be 

 involved in effluents from metallurgical plants. 

 Laboratory rats survived 2 years on a diet which 

 supplied about 18 mg/kg beryllium daily. If these 



data are transposable to cattle, it has been calcu- 

 lated a cow could drink 250 gallons of water con- 

 taining 6,000 mg/1 beryllium, without harm 

 {133). 



Boron may enter water supplies naturally, from 

 geological boron deposits, or in the form of syn- 

 thetic boranes. The latter are more highly toxic 

 (57). The lethal dose of boric acid varies from 1.2 

 to 3.45 g/kg body weight, depending on the ani- 

 mal species {27). Concentrations of 2,500 mg/l 

 boric acid in drinking water have inhibited animal 

 growth. 



Cadmium salts are found in effluent waters of' 

 various industrial plants, including electroplating, 

 textile, and chemical concerns. Ground water con- 

 tamination of 3.2 mg/1 cadmium has been reported 

 from Long Island, N.Y. {88). Data on cadmium 

 toxicities are fragmentary. The lethal dose of cad- 

 mium has been set at 0.15 to 0.3 g/kg body 

 weight for dogs and 0.3 to 0.5 g/kg for rabbits 

 {124). 



Chlorides may enter ground waters from a vari- 

 ety of sources, including natural mineral origin, 

 or sea water infiltration of subterranean water 

 supplies, from oilfield operations, and from in- 

 dustrial effluents (papermaking, galvanizing, 

 water-softening). Concentrations of chlorides of 

 1,500 mg/1 in livestock water supplies has been 

 reported safe for cattle, sheep, swine, and poultry. 



Chromium, in common with most of the trace 

 elements, appears to serve some essential func- 

 tion for animals in small concentrations, but also 

 poses a toxicity problem if present in excess. As 

 data for establishing a specific criterion for live- 

 stock use are inadequate, the criterion for farm- 

 stead water supplies appears to be satisfactory for 

 livestock as well (66). 



Cobalt: The range between adequate levels of 

 cobalt required by animals in extremely low con- 

 centrations and toxic levels is quite wide. Ac- 

 cordingly, cobalt toxicity is a rare problem and 

 is more likely to arise from contamination of the 

 dry matter of the diet than from water contamina- 

 tion. Cobalt toxicity is evidenced by a striking 

 polycythemia in various species of animals {86). 

 Levels of 100 mg/1 cobalt in drinking water for 

 rats has been reported to cause tissue damage 

 {124). 



Copper: Little information is available on toxic 

 levels of copper in drinking water for livestock 

 although the toxic effects of copper have been ex- 

 tensively studied. One is led to the conclusion that 

 most copper toxicities are feed-related rather than 

 water-related. There are, however, a number of 



135 



