ARCHIVED REPORTS_2010_4 - Laserfiche WebLink

Home Browse Search

ANNUAL SUMMARY Groundwater General Water Quality Parameters MW-4 was located directly up-gradient of the landfill based on groundwater elevations from the previously-installed wells. This well has been sampled ten times since installation. Concentration limits have been established based on Sanitas software calculations using data for MW-4. The following annual compliance review was prepared for each well: • Well MW-1:Nitrate was recorded at 3.1 mg/L and 2.0 mg/L in the first and second semesters which slightly exceeded the tolerance limit of 1.8 mg/L. No other general water quality parameters were exceeded in this well during either the 1St or 2" semester 2010 sampling events. • Well MW-2R: Nitrate was recorded at 2.8 mg/L and 2.9 mg/L in the first and second semesters which slightly exceeded the tolerance limit of 1.8 mg/L. No other general water quality parameters were exceeded in this well during either the 1 st or 2nd semester 2010 sampling events. • Well MW-3: Nitrate was recorded at 2.8 mg/L and 2.9 mg/L in the first and second semesters which slightly exceeded the tolerance limit of 1.8 mg/L. Carbonate Alkalinity was recorded at 3.1 mg/L in the first semester which slightly exceeded the tolerance limit of 2.5 mg/L. Carbonate Alkalinity is generally non-detect in the site wells and leachate. The species of Alkalinity generally present in groundwater at the site,Bicarbonate Alkalinity was less than the concentration limit in all wells. Since there is no maximum contaminant level for this parameter and the detected concentration was low,this detection is not considered an impact on water quality. No other general water quality parameters were exceeded in this well during either the 1 st or 2nd semester 2010 sampling events. • Well MW-4: No General water quality parameters were exceeded during either the 1st or 2nd semester 2010 sampling events. • Well MW-5: Nitrate was recorded at 1.9 mg/L in the second semester which slightly exceeded the tolerance limit of 1.8 mg/L. No other general water quality parameters were exceeded in this well during either the lst or 2nd semester 2010 sampling events. VOCs One VOC (Toluene)was reported in samples collected from well MW-1 during the 1st semester sampling and the retest that followed. One VOC(Trichloroethene) was reported in samples collected from well MW-3 during the 2nd semester sampling and the retest that followed. These detections will continue to be scrutinized in the future. Due to the size of the pipes serving the LFG wells in the western part of the landfill(near MW-3), it is likely that LFG is not adequately collected from that portion of the landfill. Foothill Sanitary Landfill 13 Department of Public Works/Solid Waste 2"d Semester and Annual 2010 Groundwater Monitoring County of San Joaquin—January 31,2011