Dental Materials
Volume 23, Issue 5 , Pages 527-532, May 2007

Mercury vapor levels in exhaust air from dental vacuum systems☆

Naval Institute for Dental and Biomedical Research, Building 1-H, 310A B Street, Great Lakes, IL 60088-5259, USA

Received 5 December 2005; received in revised form 2 March 2006; accepted 21 March 2006.

Abstract 

Objective

This study was undertaken to determine mercury (Hg) vapor levels in the air exhausted from dental vacuum systems.

Methodology

Hg vapor concentrations from the dental vacuum system exhaust ports of three dental clinics were measured utilizing the Jerome 431-X™ mercury vapor analyzer and the United States Occupational Safety and Health Administration's (OSHA) method ID-140 in units of ngHg/m3. Air velocity measurements and temperatures were determined with a constant temperature thermal anemometer. Hg emissions per unit time were then calculated in ngHg/min. Ambient Hg concentrations from a location approximately 1000 feet away from the closest clinic sampled in this study were measured with an Ohio Lumex Inc. RA-915+™ Hg vapor analyzer.

Results

Mean Hg vapor concentrations analyzed with the Jerome 431-X™ were: 46,526, 72,211, and 36,895ng/m3 for clinic I (110 chairs), clinic II (30 chairs) and clinic III (2 chairs), respectively. Mean Hg vapor concentrations utilizing OSHA method ID-140 were 45,316, 73,737, and 35,421ng/m3, respectively. Air flow values were: 11.6, 1.8, and 0.5standard m3/min, respectively. Hg emission data utilizing air flow measurements were calculated to be 532,684, 131,353, and 18,079ng/min, respectively, (P<0.001). There was no statistical difference between the two methods used to measure Hg vapor concentrations. The mean Hg concentration in ambient air approximately 1000 feet from the nearest clinic sampled was 13.2ng/m3.

Conclusion

The two different methods used to measure Hg vapor concentrations provided similar estimates of Hg concentrations from the exhaust air of three dental vacuum systems. Hg vapor release to the atmosphere from dental vacuums can be substantial and can exceed human exposure limits.

Keywords: Mercury vapor, Dental vacuum systems, Air flow determinations

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☆ The views expressed herein are those of the authors and do not necessarily reflect the official policy or position of the Departments of the Navy or Defense, nor the US Government. The use of commercially available products does not imply endorsement.

PII: S0109-5641(06)00088-1

doi:10.1016/j.dental.2006.03.011

Dental Materials
Volume 23, Issue 5 , Pages 527-532, May 2007

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