SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

I Wendy L. Cohen -4- 22 January 1996 Lyoth Loading Station Eight shallow borings at Lyoth, two of which were converted to shallow monitoring wells, have identified the shallow soils as consisting predominantly of silty sand to clayey silt with lesser amounts of silty clay, sand, and gravelly sand. The borings were completed to depths ranging from 21.5 to 36.5 feet bgs. The two monitoring wells were completed to 26.5 feet bgs. Ground water was encountered at 16 to 18 feet bgs in each boring. Because there are only two monitoring wells, there is no information available on ground water flow directions. All Pure The soil borings completed at All Pure show the soil consists of clay to the water table which is at approximately 15 feet bgs. The shallow ground water at this site flows towards the southwest towards the two production wells on site. Ground Water Contamination All Pure The four monitoring wells at the All Pure facility have been sampled quarterly since they were installed in 1991. Three of the four wells (MW-1, MW-2, and MW-3) are contaminated with chloroform and carbon tetrachloride. Concentrations of both chloroform and carbon tetrachloride have fluctuated, but in general, concentrations of both have increased significantly since the ground water was first sampled. The highest concentrations of chloroform have occurred in MW-3. In March 1994 chloroform was detected in this well at 2,600µg/l. The highest concentrations of carbon tetrachloride have occurred in MW-2. In June 1995, carbon tetrachloride was detected in this well at 310µg/l. The Proposition 65 Regulatory Level for chloroform is 10µg/1 and the maximum contaminant level (MCL) for carbon tetrachloride is 0.5 µg/l. Other trihalomethanes and VOCs are present in each of monitoring wells MW-1, MW-2, and MW-3. All Pure has denied responsibility for the carbon tetrachloride and other solvents present in monitoring wells MW-1, MW-2, and MW-3. However, samples collected from two of the wastewater ponds by Board staff during an inspection in 1988 showed that chloroform and carbon tetrachloride were present in both ponds. One of the ponds also had detectable concentrations of 1,1,1-trichloroethane, 1,1,2-trichloroethane, chlorobenzene, and 1,3 dichlorobenzene. Ground water level measurements at All Pure have consistently indicated that the shallow ground water flows to the southwest towards the two onsite production wells. No VOCs have been detected in MW-4 which is southwest of the two production wells. Samples from each of the production wells in 1989 showed no detectable concentrations of VOCs. A sample from one of the production wells in November 1991 also showed no detectable concentrations of VOC-'. In a separate investigation to evaluate the petroleum hydrocarbon plume from the railroad right-of-way on the east side of the plant, All Pure has identified soil and ground water contaminated with diesel fuel between a spur of the railroad and the eastern property boundary.