The feasibility of well-logging measurements of arsenic levels using neutron-activation analysis.
Arsenic is an extremely toxic metal, which poses a significant problem in many mining environments. Arsenic contamination is also a major problem in ground and surface waters. A feasibility study was conducted to determine if neutron-activation analysis is a practical method of measuring in situ arsenic levels. The response of hypothetical well-logging tools to arsenic was simulated using a readily available Monte Carlo simulation code (MCNP). Simulations were made for probes with both hyperpure germanium (HPGe) and bismuth germanate (BGO) detectors using accelerator and isotopic neutron sources. Both sources produce similar results; however, the BGO detector is much more susceptible to spectral interference than the HPGe detector. Spectral interference from copper can preclude low-level arsenic measurements when using the BGO detector. Results show that a borehole probe could be built that would measure arsenic concentrations of 100 ppm by weight to an uncertainty of 50 ppm in about 15 min.
Oden
C P
CP
US Geological Survey, Crustal Imaging and Characterization Team, P.O. Box 25046, M.S. 964, Denver, CO 80225, USA. coden@usgs.gov
Schweitzer
J S
JS
McDowell
G M
GM
D001151:Arsenic / Q000032:analysis*; D001729:Bismuth / Q000737:chemistry; D003198:Computer Simulation; D005240:Feasibility Studies; D005857:Germanium / Q000737:chemistry; D008906:Mining; D009010:Monte Carlo Method; D009501:Neutron Activation Analysis / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D005857:Germanium; C042364:bismuth germanium oxide; D001151:Arsenic; D001729:Bismuth