TABLE IV-2. 



Key Water Quality Criteria for 

 Livestock Use 



Characteristic 



Recommendations 



Total dissolved solids (TDS)_-< 10,000 mg/l, depend- 

 ing upon animal spe- 

 cies and ionic com- 

 position of the water. 

 Hazardous trace elements: 



Arsenic <0.05 mg/l 



Cadmium <0.01 mg/l 



Chromium <0.05 mg/l 



Fluorine <2.40 mg/l 



Lead <0.05 mg/l 



Selenium <0.01 mg/l 



Organic substances: 



Algae (water bloom) Avoid abnormally heavy 



growth of blue-green 

 algae. 

 Parasites and Conform to epidemic- 



pathogens. logical evidence. 



Dissolved organic Biological accumulation 



compounds. from environmental 



sources, including 

 water, shall not ex- 

 ceed established, 

 legal limits in live- 

 stock products. 

 Radionuclides Conform to recommen- 

 dations for farmstead 

 water supplies. 



ues above 4 may be detrimental because of sodium 

 phytoxicity (pp. 155, 164). Water low in salt but 

 high in bicarbonate content may present a permea- 

 bility hazard Bven with low SAR values (pp. 170— 

 171). 



Chlorides 



Although not phytoxic to most crops, some 

 chloride phytotoxicity has been found for some 

 fruit crops. No limit has been established for chlo- 

 ride-tolerant crops because detrimental effects 

 from salinity per se ordinarily deter crop growth 

 first. For chloride-sensitive crops, chloride content 

 in the soil solution may range from 10 to 50 me/1 

 with permissible levels in irrigation water ranging 

 from 1 to 20 me/1 (16). More restrictive criteria 

 should be considered where sprinkler irrigation is 

 used (pp. 155-156). 



Trace Elements 



Toxic limits which would be generally ap- 

 plicable to all soils and all crops are not easily 

 defined. Research literature is inadequate to permit 

 even well-defined guidelines. The limits suggested 

 in table IV-15 are tentative and are designed only 

 to serve as guides for well-drained soils (p. 152). 



TABLE IV-3. Suggested Guidelines for 

 Salinity in Irrigation Water 



Radionuclides 



There are many considerations involved regard- 

 ing radioactivity in irrigation water (pp. 163- 

 164). One hazard is the potential accumulation of 

 a radionuclide in a soil reaching levels in excess of 

 that applied in the irrigation water. On the basis of 

 existing knowledge, USPHS Drinking Water 

 Standards (175) is the best guide; the standards 

 are: Strontium-90, 10 pc/1; radium-226, 3 pc/1. 

 In the absence of these radionuclides, 1,000 pc/1 

 gross beta activity. 



Crop response 



TDS mg/l 



Water for which no detri- 

 mental effects will usu- 

 ally be noticed <500 <0.75 



Water which can have detri- 

 mental effects on sensi- 

 tive crops 500-1,000 0.75-1.50 



Water that may have ad- 

 verse effects on many 

 crops and requiring care- 

 ful management prac- 

 tices 1,000-2,000 1.50-3.00 



Water that can be used for 

 salt-tolerant plants on 

 permeable soils with 

 careful management 

 practices 2,000-5,000 3.00-7.50 



' Electrical conductivity. 



Microorganisms 



It is impractical to monitor irrigation water for 

 the numerous pathogenic organisms which may be 

 present (pp. 160-163). For this reason, the fol- 

 lowing guidelines for coliform limitations are sug- 

 gested for interim use subject to research confir- 

 mation. These are especially applicable where the 

 tops or roots of the irrigated crop are to be con- 

 sumed directly by man or livestock. The monthly 

 arithmetic average density of the coliform group of 

 bacteria shall not exceed 5,000 per 100 milliliters 

 and the monthly arithmetic average density of fe- 

 cal conforms shall not exceed 1,000 per 100 milli- 

 liters. Both of these limits shall be an average of 



462-246 0-72-9 



117 



