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January 14,2003 Job Number: LGO2460 Page 10 Table 5. Summary of Nitrate Mass Balance Analysis. O h p, ani x_ d ai 2 c W r Za Al of u�. R 7 d iso° C ., d v a: z dg am za z ' .[. U Parcell 10 10 525 45 1 25 1.85 1.0 Designated 3.7 43.3 525 45 25 1.85 1.0 Remainder *Note:Maximum contaminate level(MCL) for Nitrate is 10 mg/L-N and 45 mg/L as No, Please note that the average septic waste water level of 45 mg/L-N is not related to the drinking water MCL of 45 mg/L as NO;. 7.0 CONCLUSIONS AND RECOMMENDATIONS In conclusion, a satisfactory percolation rate was achieved on Parcel 1 and on the designated remainder parcel. A ground-water sample obtained from a neighboring water well was analyzed for DBCP and nitrate since no wells exist on the subject property. The water quality analysis indicated that DBCP was found to be non-detectable and that nitrate was found to be 9 mg/L as NO3 (or 2 mg/L-N). The concentration of nitrate is below the maximum contaminate level set by the United States Environmental Protection Agency of 45 mg/L as NO3 (or 10 mg/L-N). As a result of the nitrate loading analysis, an average nitrate concentration of percolating water (Nc) for the 10-acre property with a 3-bedroom residence and second dwelling units is 10 mg/L- N. The average nitrate concentration of percolating water(Nc) for the 43.3-acre property with a 3-bedroom residence including an optional second dwelling unit is 3.7 mg/L-N. The maximum ` contaminate limit for drinkingis water 10 m g/L-N (or 45-mg/L-NO3). ` The nitrate concentration of ground water is not estimated to exceed 10 mg/L-N on either parcel. Parcel 1 however has shown the potential to reach 10 mg/L-N should a residence and second unit dwelling be built on the property with full occupancy over a long period and previously ` discussed assumptions. We believe the presence of clayey soils located below the site will tend impede the downward migration of percolating water. i` D n Z •. O A