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NLS§ 4.1. The nitrate loading calculations show the resultant effluent from the subject property will theoretically possess a nitrate-nitrogen concentration of approximately one-third the Federal nitrate Maximum Contaminant Level (MCL) of 10 ppm as nitrate-nitrogen, or 45 ppm as nitrate. Although the on-site domestic well indicates no nitrate in the underlying aquifers from where the well is drawing water from,the effluent recharge remains under the MCL. Regarding the nitrate-nitrogen loading to the underlying groundwater, it is important to recognize that when adding one concentration of a solute (e.g.,N0;N in wastewater recharge)to another concentration of a solute (e.g.,NO3-N in groundwater), where both solutes are in ppm,the result is not cumulative or the sum of the two solutes. Parts per million is a mass ratio (mg perl06 mg). For example, the Nr(the resultant average concentration of nitrate in wastewater recharge in ppm of NO,), was determined to be 20 ppm from the residential structure exclusively. This equals 20 milligrams of nitrate in 106 milligrams of water ,- (one liter). If this 20 ppm concentration is added to the same volume of water(1 x 106 milligrams)of the concentration determined in the underlying aquifer the well water draws from, which was 0 ppm NO3, then the resultant concentration is now: 20 milligrams per liter+ 0 milligrams per liter=20 milligrams in 2 x 106 milligrams (2 liters, or parts per 2 million) of water. Therefore,to convert back to ppm, the numerator and denominator must be divided by 2 with the result of 10 milligrams nitrate per 1 x 106 milligrams (less than one-fourth the MCL). On a mass ratio basis,there will be a dilution effect of the nitrate concentration in the recharge water occurring in the well water aquifer. 11