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PARTICLE ANALYSIS FOR THE DETECTION OF GUNSHOT RESIDUE, 2 - OCCUPATIONAL AND ENVIRONMENTAL PARTICLES

NCJ Number
57028
Journal
Journal of Forensic Sciences Volume: 24 Issue: 2 Dated: (APRIL 1979) Pages: 423-430
Author(s)
G M WOLTEN; R S NESBITT; A R CALLOWAY; G L LOPER
Date Published
1979
Length
8 pages
Annotation
PARTICLES FROM THE HANDS OF A VARIETY OF INDUSTRIAL AND COMMERCIAL WORKERS WERE EXAMINED FOR RESEMBLANCE TO GUNSHOT RESIDUE AND THE RESULTS ARE USED TO FORMULATE CRITERIA FOR DISTINGUISHING VARIOUS PARTICLE TYPES.
Abstract
USING STANDARD EVIDENCE COLLECTION TECHNIQUES, APPROXIMATELY 80 SAMPLES WERE COLLECTED FROM THE HANDS OF WORKERS. THE SAMPLES WERE THEN STUDIED UNDER A SCANNING ELECTRON MICROSCOPE (SEM) WITH X-RAY ANALYSIS CAPABILITY. THIS TECHNIQUE IDENTIFIES THE CHEMICAL ELEMENTS PRESENT IN THE PARTICLES AS WELL AS THE PARTICLE SHAPES AND SIZES. THE INDUSTRIAL RESIDUE MOST OFTEN CONFUSED WITH GUNSHOT RESIDUE CAME FROM STUD GUNS, A FIREARM USED IN CONSTRUCTION TO DRIVE NAILS, RIVETS, AND STAPLES INTO CONCRETE, STEEL, AND WOOD. THE POWERCAPS WHICH PROPEL THE FASTENER CAN BE MADE WITH WAD-TYPE CONSTRUCTION RESEMBLING A BLANK CARTRIDGE, INCLUDING THE HEAD STAMPS. THERE IS ALSO A CRIMP TYPE POWERCAP WHICH HAS A HIGH INCIDENCE OF COPPER AND ZINC IN PROPORTIONS CONSISTENT WITH BRASS. TECHNIQUES FOR DISTINGUISHING BETWEEN STUD GUN AND GUNSHOT RESIDUE ARE GIVEN. LEAD SMELTING LEAVES LARGE AMOUNTS OF RESIDUE ON THE HAND, BUT, IN BLIND TESTS EXPERIENCED OPERATORS EASILY DISTINGUISHED THIS FROM GUNSHOT RESIDUE. THE CHEMICAL COMPOSITION OF PARTICLES ON THE HANDS OF AUTOMOBILE MECHANICS IS SIMILAR TO GUNSHOT RESIDUE, BUT ADDITIONAL ELEMENTS ARE ALSO PRESENT AND THE PARTICLES DO NOT HAVE THE SHAPE CHARACTERISTIC OF GUNSHOT RESIDUE. THIS WAS ALSO TRUE FOR PARTICLES FROM LEAD-ACID BATTERY ASSEMBLERS. ENVIRONMENTAL LEAD IS EASILY DISTINGUISHED BECAUSE IT IS FOUND IN CONJUNCTION WITH A HIGH PROPORTION OF SODIUM. THE SPARKING FLINTS USED IN CIGARETTE LIGHTERS AND SOLDER JOINTS ALSO MAY BE MISREAD AS GUNSHOT PARTICULATE. CRITERIA FOR DISTINGUISHING AMONG THESE RESIDUES ARE GIVEN. (SEE ALSO NCJ-57027.) (GLR)