Accession Number:

ADA315991

Title:

Quantitative Analysis of the Detection Limits for Heavy-Metal-Contaminated Soils by Laser-Induced Breakdown Spectroscopy.

Descriptive Note:

Final rept. 1 Jun 95-1 Jul 96,

Corporate Author:

NEBRASKA UNIV LINCOLN DEPT OF ELECTRICAL ENGINEERING

Report Date:

1996-07-31

Pagination or Media Count:

37.0

Abstract:

Laser-induced breakdown spectroscopy LIBS is a rapid remote measurement method for detection of metals in the environment. A major factor in the quantitative use of this technique involves the minimum detection limits under laboratory and field operations. NdYAG laser pulses 125 mJ, lambda 1.06 micrometers are focused on sample surfaces to produce laser sparks plasmas. Plasma emissions are recorded after interference from broadband emissions is reduced. Results are reported on the lower detection limits of As, Cd, Cr, Hg, Pb and Zn in sand, silt, clay and kaolin. Detection limits are significantly lower in sand than silt and clay. An excimer laser 125 mJ, lambda 248 nm was used for comparative LIBS analysis of lead Pb in silt. No significant difference was found in the lower detection limits using excimer and NdYAG lasers. The LIBS method must provide accurate data when used in a cone penetrometer. Conditions encountered by a cone penetrometer-based LIBS system have been simulated by compressing soil samples and then allowing them to relax for specific intervals before LIBS analysis. Results are presented of the dependence of LIBS measurements on the relaxation time after soil sample compression. This data is important for a firm understanding of detection limits for field-deployable LIBS systems.

Subject Categories:

  • Inorganic Chemistry
  • Geology, Geochemistry and Mineralogy
  • Soil Mechanics
  • Solid Wastes and Pollution and Control

Distribution Statement:

APPROVED FOR PUBLIC RELEASE