As part of the on-going stabilization action, the Emergency Response Section will be conducting an surface and subsurface soil asessment of the smelter. The target contaminants are heavy metals and the thorium and radium isotope series. The areas to be assessed include the southeast corner of the smelter, the north western boundary of the smelter along the Oxnard Industrial Drain, the eastern bank of the Oxnard Industrial Drain along the smelter and the southern interface of the smelter and the Ormond Beach Wetlands. Information collected during the IA, the stabilization action and through concerned citizens led to the investigation of this area. Information provided to OSC Wise indicated that the area may have been used as a disposal area. During the stabilization action, the START identified several areas of radioligical contamination. Gamma surveys of the area indicated residual gamma radiation in excess of 50x background (>1,000,000 cpm by NaI(Te) scintillator).
The assessment consists of the surface and subsurface gamma radiation survey, collection of surface and subsurface soilds and soil samples and collection of groundwater samples. The subsurface samples were collected using a Geoprobe with a MacroCore. Temporary groundwater wells were installed to for groundwater collection. As of June 5, 2007, 11 sample holes and 3 background holes were installed with approximately 30 samples collected. All samples locations have a temporary well casing installed. Down-hole gamma radiation monitoring was conducted on each hole to delineate the vertical extent of the contamination down the casing. The holes are continuously sampled and an aliquot is taken from each core. Aliquots are also collected by the PRPs contractor as splits. Aliquots of all cores will be field screened for metals using the Niton XRF and run through the Smith Detection System HAZMAT ID to screen for other chemical contaminants. If other chemical contaminants are detected, those samples will be submitted for laboratory anaylysis.
So far the assessment has delineated the eastern, southern and western boundaries of the contamination have been delineated. Contamination levels range from 2x background to over 100 x background. Vertically, contaminated has been delineated to depths up to 15 feet below ground surface. Contamination has also been detected along the eastern bank of the Oxnard Industrial Drain and and the southern interface of the smelter and the Ormond Beach Wetlands Further assessment is needed to complete the delineation of this assessment.
In addition to Halaco waste process solids, burn ash has also been found in the samples.
1. Delineation of the northern boundary of the contamination.
2. Vertical assessment of the Ormond Beach Wetlands directly adjacent to the southern boundary of the smelter.
3. Horizontal and vertical assessment of the contamination in the north western boundary of the smelter along the Oxnard Industrial Drain.
1. Delineation of the interface between the Halaco waste process solids and the former burn ash dump.
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