Water Quality in a Stream Receiving Dairy Feedlot Effluent1
- B. F. Hollon,
- J. R. Owen and
- J. I. Sewell2
Water quality in a stream that received effluent directly from a 200-cow dairy feedlot operation was monitored during a 22-month study to determine if the stream pollution level exceeded current Environmental Protection Agency (EPA) permissible levels for raw public water supplies, and to evaluate changes in water quality at selected distances downstream from the point source of discharge. Grab samples were collected at 2-week intervals from stations located 400 m and 3 km upstream, and 100, 500, and 1200 m downstream from the point source of discharge. Samples were analyzed for biochemical oxygen demand (BOD), chlorides, dissolved oxygen, fecal coliform, fecal streptococci, nitrate nitrogen, nitrite nitrogen, orthophosphate, total solids, and pH. Mean concentration of fecal coliform exceeded the EPA permissible level of 2,000 col/100 ml at 100 and 500 m below the point source of discharge, but not at 1,200 m. All other parameter means measured were below the permissible levels. Mean concentrations increased significantly (P < 0.01 or P < 0.05) for all parameters, except BOD and pH, when downstream stations were compared with upstream stations. However, mean concentrations significantly declined (P <0.01) for fecal coliform, fecal streptococci, BOD and orthophosphate at 1,200 m below the point source of discharge, while other parameters either declined or remained unchanged. Water quality 1,200 m below the point source of discharge apparently was not different from that 400 m above. Discharge of effluent into the stream did not appear to have a great effect on water quality, and the value of controlling the discharge would be questionable in terms of improving water quality in the receiving stream.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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