Laserfiche WebLink
Dallas Corporation -3- 15 November 1989 <br /> EXTENT OF SOIL CONTAMINATION <br /> Soil sampling conducted in November of 1988 showed that the entire extent of <br /> soil contamination was not defined. Further sampling was conducted on 1 <br /> November 1989 in order to determine the lateral extent of soil contamination. <br /> This additional sampling may be sufficient to determine the lateral extent of <br /> soil contamination. The entire extent of contamination must be determined <br /> before the HAR is complete. <br /> SITE CLEANUP <br /> About 560 cubic yards of soil and sludge with hazardous levels of nickel were <br /> removed from the impoundment in June of 1987. Approximately 700 cubic yards <br /> of impacted soil below the sludge was later removed and is presently <br /> stockpiled next to the impoundment. Sampling of soils in the walls and bottom <br /> of the existing excavation on 16 November 1988 showed that high levels of <br /> nickel and zinc are still present in some areas. Dallas Corporation desires <br /> to achieve "clean closure" . They intend to remove all soils with nickel and <br /> zinc greater than background levels from the site. <br /> The lateral extent of contaminated soils has not yet been determined. The <br /> volume of soils needed to be removed for a clean closure, therefore, is <br /> unknown. Dallas Corporation directed their consultant, Remediation Services, <br /> Inc. , to take samples at varying distances from the face of the sidewalls. I <br /> observed some of this sampling on 1 November 1989, and collected a split of <br /> one sample. Samples were collected at one foot intervals up to a depth of <br /> five feet into the sidewalls of the excavation. If the furthest samples do <br /> not contain background levels of nickel and zinc, further work will be <br /> required to determine the volume of contaminated soil . <br /> I met with representatives of Dallas Corporation and the Department of Health <br /> Services on 17 October 1989. As a result of that meeting, I understand that <br /> the cleanup will proceed in a stepwise manner. After the stockpiled soils are <br /> removed, further soil will be excavated and stockpiled. The stockpiled soil <br /> will be sampled and analyzed. Dallas Corporation will self-certify that the <br /> waste is not hazardous, if confirmed by analysis. After self-certification <br /> soil will be transported to an appropriate landfill for disposal . <br /> SITE CLOSURE <br /> Dallas Corporation submitted a closure plan to James Allen, Chief of the <br /> Northern California Section of the Department of Health Services, on 5 <br /> December 1986, and a revised closure plan on 4 April 1988. The closure plan <br /> has not yet been approved. DHS representatives told Dallas Corporation at our <br /> meeting of 17 October 1989 that the plan should be updated. <br />