Laboratory Investigation into the Contribution of Contaminants to Ground Water from Equipment Materials Used in Sampling

Benzene contamination was detected in well water samples from the Ogallala Aquifer beneath and adjacent to the Department of Energy’s Pantex Plant near Amarillo, Texas. This study assessed whether or not the materials used in multilevel sampling equipment at this site could have contributed to the contaminants found in well water samples. As part of this investigation, laboratory testing of the sample equipment material was conducted. Results from the laboratory tests indicated three different materials from two types of multilevel samplers did, in fact, contribute volatile and semivolatile organic compounds to the ground water samples from static leach tests that were conducted during an eight week period. The nylon–11 tubing contributed trace concentrations of benzene (1.37 (mu)g/L) and relatively high concentrations of the plasticizer N-butylbenzenesulfonamide (NBSA) (764 mg/L) to the water; a urethane-coated nylon well liner contributed relatively high concentrations of toluene (278 (mu)g/L) and trace amounts of NBSA; and a sampling port spacer material made of nylon/polypropylene/polyester-composite contributed trace amounts of toluene and NBSA. While the concentrations of benzene and toluene measured in the laboratory tests were below the concentrations measured in actual ground water samples, the concentrations of organics from these equipment materials were sufficient to render the results reported for the ground water samples suspect.