AECOM Report B&W - N - City of Guelph

City of Guelph2008 Annual ReportClosed Eastview Road Landfill SiteFurther to the above discussion, review of water quality further to the south of Eastview Road at monitor 9-Ihas shown a slight increasing trend for chloride and sodium starting in 2007. This is not considered to beleachate related as the PLCCS is working as designed. Similar to 2-I, the most likely source may be fromrunoff from the maintenance building that was used by the City. Further assessment of this water quality willbe undertaken as more data become available.Guideline B7 CriteriaAlthough there is no new leachate migration downgradient of the landfill, the monitors in this area were stillcompared to the RUG (Table C7 Appendix C). As observed on this table, there are several locations thatexceed the Guideline B7 criteria (RUG) for some parameters. Of all the parameters that exceed the B7 limit,only boron at location 16 is considered related to residual historical leachate impact as discussed above. Allother parameters that exceeded the B7 limit are considered to be either natural or as a result of road saltimpacts. These include:a) Chloride and sodium at locations 10-II, 10-III, 13-IV and 14-II. The parameters exceed the B7limit as a result of road salt impacts as discussed above. Further, the exceedance of chloride at2-I in the spring is also related to road salt effects.b) Sulphate at location 18-III. High sulphate concentrations at location 18 have been discussed inthe past and are related to gypsum (1992 Groundwater and Surface Water Monitoring Report –Eastview Road Landfill Site, GLL 93-134, dated June 1993).c) Elevated iron and manganese were once again noted at locations 2, 9, 10, 13, 14, 15, 16, 18 and35. These elevated parameters are considered naturally occurring and are created by thewetland and associated peat (iron) and in the outwash sand (manganese) as discussed inSection 4.3.The chemistry trends to the west of the site are provided in Appendix C (Figures C4 to C6). Groundwaterquality in this area is similar to previous years showing road salt effects and exhibits no leachate impacts,although increasing road salt effects continue to be noted at 30-I. This would be expected as groundwaterflow from the west is towards the site.In conclusion, there are no new exceedances of Reasonable Use measured in the shallow groundwaterdowngradient of the landfill. Some exceedances due to minor residual leachate effects still exist, but theseare continuing to decrease over time.4.4.2 Predicted Exceedances of Reasonable UseIf the PLCCS continues to work as designed to prevent any further off-site migration of leachate, no newexceedances of the Reasonable Use Guidelines related to the landfill are predicted in the shallowgroundwater.(111414_2ra_apr29-09_city_of_guelph.doc) - 25 -