Personal Mercury Monitor for Exposure Measurements - Personal Mercury Monitor for Exposure Measurements
Project Summary/Abstract
Workers in the oil and natural gas industry are vulnerable to exposure to toxic mercury (Hg) vapor as a
result of routine inspection and maintenance of equipment such as compressors and other process equipment
that concentrate species of low volatility over time. Exposure of workers to elemental mercury vapor is of
concern in many other industries as well, including the chlor-alkali industry where mercury is used as an
electrode, gold and silver mining where these precious metals are extracted with mercury, manufacture and
recycling of fluorescent lamps, Super Fund site cleanup, dentistry, etc. As a result, there is a great need for a
personal mercury monitor to protect the health of industrial workers. For the oil and gas industry, which is the
largest potential market for a personal mercury monitor, there is an additional requirement that that the monitor
be certified for operation in explosive atmospheres. Currently, no mercury monitor has the required ATEX
(ATmosphères EXplosibles) certification for use in this industry where explosive atmospheres occasionally occur
by accident. Also, for the oil and gas industry, the monitor must have high selectivity against other UV-absorbing
species such as aromatic hydrocarbons (benzene, toluene, xylenes, etc.), which may be present at up to high ppm
levels. In our Phase 1 work, we developed and launched the Hermes 1 Personal Mercury Monitor™ as a product
for measuring mercury vapor in the workplace. This pocket-sized instrument, which is based on atomic
absorbance of the 254-nm emission line of a low pressure mercury lamp, measures mercury concentrations down
to 0.1 g/m3 (compared to the OSHA 8-hr exposure limit of 100 g/m3) and achieves high selectivity against other
UV-absorbing species by the innovative means of modulating the sample flow through a silver wool scrubber to
selectively remove Hg by forming an amalgam. To the extent that aromatic hydrocarbons pass through the
scrubber and are not modulated, they do not interfere with the measurement. The Hermes 1 may be used in
nearly all industrial settings except for the oil and gas industry where explosive atmospheres may be encountered.
Therefore, during the Phase 2 project we will redesign the mechanical and electronic components of the Hermes
1 to meet the requirements of ATEX Zone 1 certification. In Phase 2 we also will optimize the design of the silver
scrubber to provide greater capacity for mercury removal and quantify selectivity factors for species likely to be
found in the oil and gas atmospheric environment. The deliverable for this project will be the product launch of
the Hermes 2 Personal Mercury Monitor™, which can be safely used in the oil and gas industry for personal
monitoring of thousands of workers to protect from exposure to dangerous levels of this potent neurotoxin.
