WORK PLANS - Laserfiche WebLink

Home Browse Search

Based upon the similarity '! in results between "background" and selected soil samples from within the Annex, two possible conclusions might be reached. The first conclusion might be that the samples taken as background are in fact representative of ambient soil conditions. The second conclusion might be that the entire site is contaminated, hence the similarity between "inside" samples and "background" samples. Of the two choices, the first seems more reasonable. Therefore it is reasonable to accept tre proposed "background" levels as representative of ambient conditions at the Lika Site. It is noted that the buildings on the Lika Site are underlain by fill material available from dredging of the adjacent waterways, which would not be native to the surrounding area. Extent of Contamination It is currently proposed t4,at the Lika Site be returned to its original condition through ' removal to background. This is an acceptable site mitigation criteria and is preferred where achievable. Woodward-Clyde implies that this condition can be achieved. However, it is noted that if the contaminants of concern have reached ground water, ihemoval of soil to the water table, if not below the water table, would be required to achieve "background" conditions. It appears that the current proposal does not address this possibility. 1 It is also noted that elevated levels of copper were reported in boring LB-12 . This boring corresponds to the location of monitor well MW-12 , which is adjacent to a sump discharge line. one sample from this boring (Sample LB-11-2) is described as having " . .obvious blue streaks. " These data indicate that possible leakage from the discharge line has occurred. Possible discharge from this line is indicated in section 1. 0 of the Woodward-Clyde report entitled "Lika Corporation Field Avenue Annex Preliminary Investigation for Surface and Subsurface Contamination of Soils and Ground Water - Final Report, " where " . . . corroded ductile iron pipes. . " are mentioned. If the sump discharge line has leaked, the extent of soil contamination would be beyond that currently described for excavation. If there are leaks in the line, at a minimum the line should be removed from service or repaired. Removal of contaminated soils could be required if the return of the site to prior "background" conditions is proposed. i Other Issues In addition to the above, other issues should be resolved before proceeding with the proposed remedial action. Specifically, an explanation as to how wastes escaped the building to contaminate the adjacent 11197 ' strip" should be presented. It is noted that the proposed excavation could go both laterally and vertically beyond the fill material surrounding the concrete sumps. Appropriate health and safety practices, including any necessary shoring, should be included in the final proposed plan of action.