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1 April 13, 2000 <br /> Job Number: LG00-114 <br /> Page 6 <br /> :Borings B-2 and B-3<are dissimilar to B-1 in composition in that a hard.pan zone was. <br /> found to exist between 2.5 to 8 feet in depth(Plates 9 and 10). -Nomoist.zones wereencountered <br /> in B-2 or.B-3: A one'foot thick medium sand was encountered at 16:5 feet in B-2 and 14.5-in B- <br /> 3.. The percolation,capacity ofthis sand was tested in the percolation test at B=3. <br /> One(-1)Npercolation test was performed within B-3 at a depth'of 15 feet. The percolation <br /> test casing.was-2 inchldiameter.PVC pipe with slots and an open end on the bottom. Two inches ' f <br /> r of"pea gravel"was placed in the bottom of the hole,-the casing was installed, and one (1)foot of <br /> "pea.gravel"was,backfilied_in the annular space.'/A one(1) hour percolation test was conducted on April 6,2000 in accordance.with the <br />�— requirements of San Joaquin County Environmental Health Division. The entire test"was <br /> observed by Adieene Ellsaesser:of that office_ A satisfactory peculation rate of 0.31 min/in was , <br /> ;< measured for the percolation test'(Plate 11)_ <br /> _ VII. NITRATE LOADING STUDY N <br /> A,build'up of'1nitrates in the upper.ground-water zones can-cause a temporary blood <br /> disorder in infazits call ed,riiethemogiobinemia(blue.baby): Serious and occasionally fatal j <br /> poisonings of infants have occurredfallowing the ingestion of water containing nitrate <br /> concentrations greate l than 10 mg/l nitrate as N or 45 mg/l nitrate as.NO3: <br /> Fj- <br /> d <br /> Because'of the"concern of nitrate leaching into grounwater;a nitrate loading analysis.is <br /> required to estimate the average nitrate concentration of percolating water for the subject parcel. <br /> f The nitrate sources inblude the septic effluent and deep percolation of rain water. The nitrate <br /> concentration of the Heated septic effluent mixed-with the'deep percolating rain water is estimated <br /> before it mixes with ground wafer and dilutes. The nitrate balance method-assumes 100% mixing <br /> with rain water,over an average-yearly period for the acreage of the"subject parcel: <br /> rThe method is based on a'siinple�mass balance formula which takes into,account soil <br /> denitrification factor, rain fall amount,.rain fall,nitrate concentration,' the waste.efflueint quantity, <br /> and waste eluent nitrate,concentration. The formula;assumptions and'ealculations.for the t <br /> analysis are shown on'Plates-11'and 12..The units-of nitrate used in the.mass balance equation"is <br /> nitrate-N whose maximum drinking water contarnurate level,ls 10 <br /> t-� <br />