0141734 



4.0 HAZARD LEVELS FOR WATER 



A large number of factors influence the suitability of water 

 for livestock consumption and for irrigation purposes. Some of 

 these are discussed in the following sections. A computer litera- 

 ture review was not conducted for this subject. 



4.1 Water Quality Levels for Livestock 



A number of factors, including animal tolerance, water con- 

 sumption and forage ingestion, are involved in the determination 

 of the suitability of a water source for livestock. Water con- 

 sumption by livestock is influenced by the species, the age, the 

 condition of the animals and climatic factors. Temperature 

 changes have been shown to vary water consumption in cattle by a 

 factor of three (Rittenhouse and Sneva 1973). The moisture 

 content of forage affects water consumption and some species such 

 as sheep have been shown to subsist entirely on dew or snow 

 (3utcher 1973). Water consumption by domestic livestock varies 

 between 1 and 4 gallons per day for sheep or goats and 10 to 16 

 gallons per day for dairy cattle (Federal Water Pollution Control 

 Administration 1968) . It is clear that any given amount of heavy 

 metal in water will likely affect individual animals in a slightly 

 different manner. 



The heavy metal content of forage and soil is another factor 

 which influences the allowable amount of heavy metals in livestock 

 drinking water. Contaminated water will only exacerbate toxicosis 

 produced from ingesting contaminated forage. Mayland et al . 

 (1975) estimated cattle ingested soil in the amount of 100 to 1500 

 g/animal/day . In areas with high levels of heavy metals in soils, 

 this source may represent a considerable fraction of the total 

 heavy metal intake in some animals. 



Several organizations have established suitability criteria 

 levels for most consti tutents found in water. Criteria for 

 arsenic, cadmium, lead and zinc are reviewed in Table 45. 



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