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July 24,2003 Job Nuinber:LG03-206 r Page 7 r A build,up of nitrates in drinking water•can cause a temporary blood disorder in infants called f,3 methemoglobinemia(blue baby syndrome). Serious and occasionally fatal-poisonings of infants 'have occurred following the ingestion of water containing nitrate concentrations greater than 10 - mg/L nitrate as N. The method utilized for the nitrate loading analysis is based on a simple mass balance formula, ' discussed in a published article by Hantzsche and Finnemore(1992);which provides a convenient and simplified method to estimate long-term ground-water nitrate impacts on area- wide basis. Hantzsche and Finnemore found that over a,long period of time,water quality in the upper saturated ground-water zone closely approximates the quality of percolating'recharge waters. They believe that their method is a good planning tool and provides useful information to planners and local officials but with some real limitations specifically; ":..the ea�_.r_�uatidn ignores dispersion, lateral flow, and mixing with g_ound water flow from ups-gradient areas:. These processes would generally contribute to additional reduction of nitrate-nitrogen concentrations in ground water to the extent that the`nitrate.nitrogen concentration of ground-water flow from up-. r . gradient areas is lower:" Hantz_sche and Fennemore indicate that the approach to predicting nitrate buildup in ground water is."::.a conservative (worst case) first approximation of ground-water nitrate-nitrogen concentration resulting from the'combined effect of on-site sewage disposal systems and precipitation. This (the equation and approach)is for estimation of long-term effect(i.e.; over years)on ground-water quality, and is not intended for prediction of seasonal'changes." The method tabes into account development area, soil denitrification factor,.rainfall volume, rainfall nitrate concentration, the waste effluent quantity, and waste effluent nitrate concentration.. The formula, assumptions and calculations used for the anal sis are shown on Plates 8 and 9.The p Y units"of nitrate used in the mass balance equation are nitrate-N whose maximum drinking water contaminate.level is 10 mg/L. These variables are discussed next. 6.2 . Quantity and Quality of Septic System Effluent. We understand that the hours of.operation will be Monday thru Saturday, 9:00 AM to 5.00 PM, The facility will be run by 5 regular volunteers and have about 2 to 10 visitors er day.