Occupational Exposure to Airborne Mercury During Gold Mining Operations Near El Callao, Venezuela

Details

• Personal Author:
  Drake P ; Jenkins M ; Mueller, Charles A. ; Reh, Christopher M. ; Rojas M
• Description:
  The National Institute for Occupational Safety and Health (NIOSH) recently conducted a cross-sectional study during gold mining operations near El Callao, Venezuela. The purpose of the study was to assess mercury exposures and mercury-related microdamage to the kidneys. The study consisted of concurrent occupational hygiene and biological monitoring, and an examination of the processing techniques employed at the different mining facilities. Mercury was used in these facilities to remove gold by forming a mercury-gold amalgam. The gold was purified either by heating the amalgam in the open with a propane torch or by using a small retort. Thirty-eight workers participated in this study. Some participants were employed by a large mining company, while others were considered "informal miners" (self-employed). Mercury exposure was monitored by sampling air from the workers' breathing zones. These full-shift air samples were used to calculate time-weighted average (TWA) mercury exposure concentrations. A questionnaire was administered and a spot urine sample was collected. Each urine sample was analyzed for mercury, creatinine, and N-acetyl-beta-D-glucosaminidase (NAG). The range for the 8-h TWA airborne mercury exposure concentrations was 0.1 to 6,315 micrograms/m3, with a mean of 183 micrograms/m3. Twenty percent of the TWA airborne mercury exposure measurements were above the NIOSH recommended exposure limit (REL) of 50 micrograms/m3, and 26% exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 25 micrograms/m3. The mean urine mercury concentration was 101 micrograms/g creatinine (microgram/g-Cr), and the data ranged from 2.5 to 912 micrograms/g-Cr. Forty-two percent of the study participants had urine mercury concentrations that exceeded the ACGIH biological exposure index (BEI) of 35 micrograms/g-Cr. Urinary NAG excretion is considered a biological marker of preclinical, nonspecific microdamage to the kidney's proximal tubule cells. The mean urine NAG concentration was 3.6 International Units/g-Cr (IU/g-Cr) with a range of 0.5 to 11.5 IU/g-Cr. Three workers had urine NAG levels in excess of the reference values. Correlation analyses found statistically significant correlations between airborne mercury exposure and urine mercury level (P = 0.01), and between urine mercury level and urine NAG excretion (P = 0.01). In addition, the airborne mercury exposure data and urine mercury data were segregated by job tasks. A Wilcoxon rank sum test revealed significant correlations between tasks and mercury exposure (P = 0.03), and between tasks and urine mercury level (P = 0.02). The tasks with the highest mean airborne mercury exposures were "burning the mercury-gold amalgam" and "gold refining/smelting". Recommendations were provided for improving the retort design to better contain mercury, for ventilation in the gold shops, and for medical surveillance and educational programs. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Dust Environmental Monitoring Mercury Mining Occupational Exposure Occupational Health Particulate Matter Safety Surveys And Questionnaires Urogenital Diseases Urogenital System

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• Keywords:
  Air-samples Air-sampling Airborne-dusts Airborne-particles Author Keywords: Gold Mining Biological-monitoring Biological Monitoring Breathing-zone Exposure-assessment Exposure-levels Exposure-limits Gold-mines Kidney-damage Mercury Mercury-compounds Miners Mining-industry NAG Occupational-exposure Occupational Exposure Questionnaires

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• Series:
  Mining Publications
• ISSN:
  0340-0131
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 10 ; OSHA Region 5 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  SRL - Spokane Research Laboratory ; DSHEFS - Division of Surveillance, Hazard Evaluations, and Field Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  206-212
• Volume:
  74
• Issue:
  3
• NIOSHTIC Number:
  nn:20021719
• Citation:
  Int Arch Occup Environ Health 2001 Apr; 74(3):206-212
• Contact Point Address:
  National Institute for Occupational Safety and Health, Spokane Research Laboratory, 315 East Montgomery, Spokane, WA 99207, USA
• Email:
  pcd8@cdc.gov
• CAS Registry Number:
  Mercury (CAS RN 7439-97-6)
• Federal Fiscal Year:
  2001
• Peer Reviewed:
  True
• Source Full Name:
  International Archvies of Occupational and Environmental Health
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b4d74af6afa8bc2861bf9aa231c9390496c7a482e9e7c13a9ea9ef05876d8bb8ecd51ec03e2d05a9f4f381fcb7ae8296016b2ce6f10960d8512ade04d73246f5
• Download URL:
  https://stacks.cdc.gov/view/cdc/220505/cdc_220505_DS1.pdf
• File Type:
  [PDF - 108.85 KB ]