The study examined the magnitude of a release of indicator bacteria (fecal coliform) from bovine fecal deposits that were rained on by a rainfall simulator at a rate of 6.1 ± 0.3 cm/h for 15 min, as affected by duration of rainfall and age of fecal deposits. Standard fecal deposits were placed on a platform and rained on with the runoff water being sampled at 5, 10, and 15 min. Samples were then examined by the most probable number (MPN) method for the presence of fecal coliforms. Results indicate the potential for bacterial pollution from bovine fecal deposits. An equilibrium in the concentration of fecal coliforms being released from the fecal deposit was reached within 10 min. Fecal deposits < 5 d of age released fecal coliforms on the order of millions/ 100 mL of water. Concentrations declined to 40,000/100 mL at 30 d of not-rained on age. The decline followed a typical bacterial death curve. Additional Index Words: grazing, riparian zones, feedlots. Thelin, R., and G. F. Gifford. 1983. Fecal coliform release pattern from fecal material of cattle. J. Environ. Qual. 12:57-63. Few studies have been conducted on the time relationships in coliform release from cattle fecal material. Most studies on bacterial pollution from grazing activities have been centered on the presence of bacteria in streams of grazed watersheds (Darling and Coltharp, 1973; Dixon et al., 1977; Doran and Linn, 1979; Johnson et al., 1978; Kunkle, 1970; Kunkle and Meiman, 1967; Milne, 1976; Morrison and Fair, 1966; Skinner et al., 1974; Stephenson and Street, 1978). These studies led to the conclusion that the presence of cattle on a watershed does increase the concentration of coliform bacteria in the stream system of that watershed. Cattle as a Source of Bacterial Pollution Doran and Linn (1979) state that over one-third (3 x 10 ha) of the land area of the continental United States is used for grazing livestock, and it receives 50% of all livestock wastes. Infectious diseases of microbiological etiology, originating in man and other animals, are transmitted through waters that receive animal wastes (Diesch, 1970; Robbins et al., 1972). Studies conducted on western mountain streams have implicated wild and/or domestic animals as a source of potentially pathogenic enteric bacteria in surface waters (Fair and Morrison, 1967, Walter and Bottman, 1967). It has been concluded that the discharge of pathogens into streams is most clearly associated with livestock production. The extent of that discharge into surface waters is, however, poorly documented (McElroy et al., 1975). A list of dis1 This work was supported jointly by the Utah Agricultural Exp. Stn. (Proj. 773, 771, and 749) and the U.S. Dep. of the Interior, Office of Water Research and Technology, Project no. JNR 048Utah, Agreement no. 14-34-001-0147, as authorized under the Water Resources Research Act of 1964, as amended. Technical Paper no. 2747, Utah Agric. Exp. Stn., Logan, UT 84322. Received 11 Aug. 1982. 2 Graduate Research Assistant and Professor and Chairman, respectively, Watershed Science Unit, Range Science Dep., College of Natural Resources, Utah State University, Logan. J. Environ. Qual., Vol. 12, no. 1,1983 57 eases capable of being transmitted through animal waste has been given by Ellis and McCalla (1976). Several factors determine the potential of livestock grazing to serve as a nonpoint source of pollution. Sweeten and Reddell (1978) list the following: (i) stocking density, (ii) length of grazing period, (iii) average manure loading rate, (iv) manure spreading uniformity by grazing livestock, and (v) disappearance of manure with time. Sweeten and Reddell (1978) maintain that under normal conditions, rangeland grazing of cattle would not contribute measurable quantities because of runoff dilution factors ranging from 100:1 to 25,000:1. They do not take into account, however, the position of the fecal matter relative to the stream. Kunkle (1970) found that grazing near a channel significantly impacted stream bacterial densities, while grazing some distance from the channel area had very little impact. Also, as previously stated, many studies have shown that the presence of cattle did increase bacterial counts in nearby streams. The longevity of bovine fecal deposits can be impressive. Deposits have remained on soil and plant surfaces up to 1.5 y, depending on climate, insect, and biological activity (Marsh andCampling, 1970). Apparently, coliform bacteria within a fecal deposit were able to survive intense sunlight and heat for at least one summer (Buckhouse and Gifford, 1976). Clemm3 found that fecal coliforms and fecal streptococci can survive for > 1 y in bovine feces. It is reasonable to conclude that bovine fecal deposits are capable of providing a long-term continuous source of potential pollution to surrounding areas. Perhaps the bacterial pathogens in cattle feces of most interest from the human health standpoint are those of the genus Salmonella. Reasoner (1974) found that in the United States in 1972 more Salmonella isolations (220) were obtained from cattle than from any other animal. In clinically healthy cattle, about 13% have been found to be infected with Salmonella (Prost and Riemann, 1967). During a water quality survey, started in 1970 on Toughannock Creek in New York state, Salmonellae were found in a small tributary stream on which a cattle feedlot was located (Dondero et al., 1977). Fecal Coliforms as Indicator Bacteria Bacteriological water quality is determined by examining water samples for the presence of indicator bacteria. Indicator organisms are used instead of the actual pathogens for a number of reasons. Indicator bacteria are usually present in greater numbers than pathogens, and are easier to isolate and much safer to work with. The premise followed is that if the indicator organisms are present in certain amounts, then there is a good likelihood that pathogenic organisms are also present. Three groups of indicator bacteria are commonly used in water quality studies. These are total coliforms, fecal coliforms, and fecal streptococci. The sensitivity 3 D. L. Clemm. 1977. Survival of bovine nteric bacteria in forest streams and animal wastes. M.S. Thesis. Central Washington U iv., Ellensburg. 58 J. Environ. Qual., Vol. 12, no. 1, 1983 of each group for determining fecal pollution varies. Also, the practicality of testing for each type of organism in a large number of samples affects its choice as a good indicator organism. Many workers (Doran and Linn, 1979; Dutka, 1973; Kunkle and Meiman, 1967; Kunkle and Meiman, 1968; Meiman and Kunkle, 1967; Schuettpely, 1969; Stuart et al., 1971) agree with Geldreich (1970) when he states following: Occurrence of fecal contamination in water can most accurately be detected and measured by a fecal coliform test that is based on lactose fermentation at 44.5°C…this pollution indicator system has an excellent positive correlation with warm-blooded animal fecal contamination. The fecal coliform test is really an examination of Escherichia coli. This organism, like the pathogens Salmonella and Shigella, is an inhabitant of the intestinal tract of man and other mammals (Stainer et al., 1979). The consensus on total coliform as an indicator organism is becoming one that holds the test as being insensitive in detecting fecal pollution due to much confounding in the environment (Doran and Linn, 1979; Dutka, 1973; Stephenson and Street, 1978). The basis of this belief is stated by Geldreich (1970): The total coliform group not only measures the fecal contamination present in the water, but also includes a varying proportion of organisms that are of limited sanitary significance and capable of excessive regrowth in nutrient rich water. The drawback of using fecal streptococci as an indicator of fecal pollution is one of practicality. The use of this group in the undifferentiated form is inferior to the fecal coliform test for the following reason: Fecal streptococci are present in substantial numbers on vegetation and insects, whereas fecal coliforms are either not observed on vegetation or only on those insects that may spend part of their life cycle in contact with fecal wastes (Geldreich et al., 1964). This can lead to the presence of fecal streptococci in runoff water when no fecal contamination is present (Hunt et al., 1979). Fecal Coliform Survival Outside the Host The importance of fecal coliforms as indicator organisms depends in part upon their ability to survive outside the intestinal tract of cattle. Their survival in water depends upon the physical and chemical composition of the water (McFeters and Stuart, 1972). Temperature the parameter cited most often as exerting a major influence on the survival of enteric bacteria (Davenport et al., 1976).3 Their studies and others have shown that bacterial survival is inversely related to temperature below 15°C. From these, it has been suggested that maximum survival under natural conditions occurs in 0°C water under ice cover. In Colorado, Kunkle and Meiman (1967) found extremely low counts of fecal coliforms and fecal streptococci in high elevations (cold water) streams. In Montana, however, Goodrich et al. (1970) found some of the highest coliform counts in the highest, coldest, and most primitive tributaries of Bozeman Creek. Moreover, Hendricks and Morrison (1967) found that E. coli and other enteric bacteria, some of which are pathogens, not only survived, but grew and multiplied in dilute nutrient –low temperature environments representative of a cold mountain stream. Andre et al. (1967) studied the survival of bacterial pathogens in farm pond water. They determined that Salmonella species survived about 16 d, while Shigella species survived about 12 d, indicating survival of enteric pathogens in pond water for a significant time interval.
