FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN SOIL AND SEDIMENT OHIO LUMEX'S RA-915+/RP-91C MERCURY ANALYZER
Ohio Lumex's RA915+/91 C mercury analyzer was demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003, at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration was to collect reliable performance and cost data for the RA915+/91C and four other field measurement devices for mercury in soil and sediment. The key objectives of the Demonstration were: 1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical quantitation limit (POL); 2) determine analytical accuracy associated with vendor field measurements using field samples and standard reference materials; 3) evaluate the precision of vendor field measurements; 4) measure time required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital, labor, supplies, and investigation-derived wastes.
The Demonstration also involved analysis of standard reference materials (SRMs), field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those for an off-site laboratory using reference method, "Test Methods for Evaluating Solid Waste" (SW-846) Method 7471B.
The sensitivity, accuracy, and precision measurements were successfully completed. Results of these measurement evaluations suggest that the Ohio Lumex field instrument can perform as well as the laboratory analytical method. Accuracy comparisons to standard reference materials showed statistical equivalence but field sample analysis suggested possible matrix interferences. Field instrument precision was better than laboratory precision as determined by relative standard deviation calculations. During the demonstration, Ohio Lumex required 21.25 hours (1,275 minutes), for analysis of 197 samples. The cost per analysis, based on measurement of 197 samples, when incurring a minimum 1-month rental fee for the RA-915+/RP-91 C, was determined to be $23.44 per sample. Excluding the instrument rental cost, the cost for analyzing the 197 samples was determined to be $15.82 per sample. Based on the 3-day field demonstration, the total cost for equipment rental and necessary supplies was estimated at $8,600. The cost breakout by category is: capital costs, 32.5%; supplies, 10.8%; support equipment, 6.0%; labor, 19.5%; and IDW disposal, 31.2%.
The RA915+/RP-91C exhibited good ease of use and durability, as well as no major health and safety concerns. However, the device portability is somewhat limited by its size. Additionally, the device is readily available for purchase or lease. The Demonstration findings collectively indicated that the RA915+/RP-91 C is a reliable field mobile measurement device for mercury in soil.
The Demonstration also involved analysis of standard reference materials (SRMs), field samples collected from four sites, and spiked field samples for mercury. The performance results for a given field measurement device were compared to those for an off-site laboratory using reference method, "Test Methods for Evaluating Solid Waste" (SW-846) Method 7471B.
The sensitivity, accuracy, and precision measurements were successfully completed. Results of these measurement evaluations suggest that the Ohio Lumex field instrument can perform as well as the laboratory analytical method. Accuracy comparisons to standard reference materials showed statistical equivalence but field sample analysis suggested possible matrix interferences. Field instrument precision was better than laboratory precision as determined by relative standard deviation calculations. During the demonstration, Ohio Lumex required 21.25 hours (1,275 minutes), for analysis of 197 samples. The cost per analysis, based on measurement of 197 samples, when incurring a minimum 1-month rental fee for the RA-915+/RP-91 C, was determined to be $23.44 per sample. Excluding the instrument rental cost, the cost for analyzing the 197 samples was determined to be $15.82 per sample. Based on the 3-day field demonstration, the total cost for equipment rental and necessary supplies was estimated at $8,600. The cost breakout by category is: capital costs, 32.5%; supplies, 10.8%; support equipment, 6.0%; labor, 19.5%; and IDW disposal, 31.2%.
The RA915+/RP-91C exhibited good ease of use and durability, as well as no major health and safety concerns. However, the device portability is somewhat limited by its size. Additionally, the device is readily available for purchase or lease. The Demonstration findings collectively indicated that the RA915+/RP-91 C is a reliable field mobile measurement device for mercury in soil.