WASTES IX RELATION TO AGRICULTURE AND FORESTRY 



25 



lakes, canals, and tributary streams. Aquatic 

 plants must have mineral nutrients to nourish ; and 

 flourish they will if the plant food is there. Lack of 

 phosphorus appears to be the main limiting factor 

 in the growth of these plants in most waters, but 

 nitrogen is also required. 



These nutrients may enter surface waters by 

 way of runoff from fertilized fields ; runoff from 

 barnyards and f eedlots ; municipal and rural sew- 

 age; sanitary facilities in recreation areas; and 

 industrial wastes. 



Accumulations of water-loving plants on farm 

 ponds and similar surface waters impair use of the 

 water for recreation. Such plants may reduce fish 

 production and harvesting, impede boating and 

 swimming, and provide a good habitat for mos- 

 quitoes and snakes. When these plants die, they 

 become a pollutant with high oxygen demand while 

 deteriorating. In turn, this deterioration evolves 

 offensive odors, bad tastes, and seriously impairs 

 fish life. 



As of June 30, 1965, the Department of Agricul- 

 ture had given technical or cost-sharing assistance, 

 or both, in constructing 1,420,733 farm ponds. Un- 

 wanted growth of water plants now limits the use- 

 fulness of an appreciable number of these ponds. 



Canals and ditches used for irrigation and drain- 

 age may have their usefulness seriously impaired 

 by becoming clogged with growths of aquatic 

 weeds. Measurements have shown that ditch ca- 

 pacity may be reduced to one-third or one-fourth 

 and the reduced capacity may contribute to flood- 

 ing. The control of aquatic weeds in irrigation 

 ditches is a major item in the maintenance costs 

 to irrigation and drainage districts. 



As of June 30, 1965, the Department of Agricul- 

 ture had provided technical or cost-sharing assist- 

 ance, or both, in establishing 37,179 miles of irriga- 

 tion canals and laterals, as well as 279,256 miles of 

 drainage mains and laterals. These figures do not 

 reflect the total installation of these waterways, 

 since the Bureau of Reclamation, State agencies, 

 and private concerns were also involved in ditch 

 construction and maintenance. 



Agriculture and forestry are indeed adversely 

 affected when plant nutrients become wastes in 

 surface waters and thereby permit aquatic weeds 

 to luxuriate. 



Concern is mounting over the presence of nitrate 

 and small amounts of nitrite in ground water in 



many parts of the country because of the toxic 

 effects on livestock and rural people using wells for 

 drinking water. 



The sources of nitrate and nitrite in ground wa- 

 ter are usually considered to be (a) naturally oc- 

 curring accumulations, (5) nitrogen fertilization, 

 (<?) sewage, (d) corrals, and (e) industry. 



Farmers must be concerned with the nitrate con- 

 tent of the water in their wells. Xitrate poisoning 

 can affect both cattle and infants. In ruminants, 

 such as cattle, micro-organisms in the rumen re- 

 duce the nitrate to nitrite. Nitrite converts the 

 hemoglobin in red blood cells to methemoglobin, 

 which cannot transport needed oxygen from the 

 lungs to body tissues. Thus, nitrate poison shows 

 the general symptoms of oxygen deficiency. Since 

 swine are not ruminants, they are much less sus- 

 ceptible to nitrate poisoning than cattle are. An 

 example of damage to agriculture by an industry 

 was recently reported in the West where a fer- 

 tilizer plant was put in operation slightly up- 

 stream from a large cattle and sheep enterprise. 

 Shortly thereafter, this livestock enterprise expe- 

 rienced abortions of 3,100 ewes and 300 cows. 

 Losses in lamb and calf drops from nitrate in 

 water or feed have long been recognized as serious. 



In infants, particularly those under 6 months of 

 age, the pH of the stomach tends to be above 4, 

 permitting growth of organisms that reduce ni- 

 trate to nitrite. Here again, in such infants the 

 hemoglobin is also converted to methemoglobin, 

 causing an affliction known as "blue baby." The 

 incidence of blue babies is largely on farms de- 

 pending on well water for drinking. 



From 1947 to 1950, 139 cases of infant methemo- 

 globinemia (blue baby), including 14 deaths, from 

 nitrate in farm wellwater supplies were reported 

 in Minnesota alone. Adults drinking the same 

 water are not affected, but breast-fed infants of 

 mothers drinking such water may be poisoned. It 

 has been reported that cows drinking water con- 

 taining nitrate may produce milk sufficiently high 

 in nitrate to result in infant poisoning. 



There are no reports of methemoglobinemia in 

 infants fed water from public water supplies in 

 the United States, although levels in nitrate in 

 some may be in excess of 45 nig. liter. Thus, the 

 evidence shows that farm people are the ones who 

 are adversely affected by nitrate in water supplies. 



