WATER RESOURCES OF ORANGE COUNTY 129
this 142-feet deep well carries appreciable quantities of cow manure. On January 8, 1964, the water draining into the well had the following concentrations in ppm: sodium, 58; potassium, 54; chlorides, 64; fluorides, 3.8; and phosphates, 34. All of these concentrations are much higher than the natural water of the area. Water from a 289-foot deep well (836-125-2) which is 1,000 feet downgradient from well 836-125-1 had the following mineral concentrations in ppm on March 16, 1964: sodium, 15; chlorides, 13; and fluorides, 0.6. These concentrations are abnormally high for the area and indicate that polluted water from the drainage well is probablly entering the supply well. Another drainage well near Winter Garden (833-134-2) receives water from tile drains that underlie a citrus grove. On January 8, 1964 the water entering this well had the following concentrations of mineral constituents in ppm: sodium, 15; potassium, 15; sulfate, 156; chloride, 48; fluoride, 2.0; and nitrates 104. All of these concentrations are much higher than the concentrations in the natural water in the area. The higher than normal concentrations of potassium and nitrates definitely indicate pollution from fertilizer.
General areas where bacterially polluted water has been found in some wells by the Orange County Health Department are shown in figure 60. Most wells in the indicated areas are probably not polluted but the map shows areas where pollution is more prevalent than in other areas of the county. Orange County Health Department records show that in the 5-year period 1959-1964 approximately 50 wells showed evidence of bacterial pollution. The indicator bacteria are not harmful but indicate that harmful organisms could be present. It is probable that many private wells have at some time contained polluted water, but it was not discovered because samples were not taken for bacterial analyses.
A salt test similar to the Live Oak test was made in Orange County in March 1961 by the Orange County Health Department. A drainage well located in the northwestern corner of Lake Pleasant in the northwestern part of Orange County was suspected of causing pollution in nearby supply wells. Within a few hours after water from the lake was allowed to drain into the well on September 24, 1960, water from supply wells in the area became polluted. Water pumped from the Northcrest Public Supply well which is located 1,000 feet to the northwest and cased 60 feet deeper than the bottom of the drainage well suddenly became muddy, high in bacteria count, and had an unpleasant taste and odor. The pollution cleared up after the drainage well was shut down and returned