1. Field of the Invention
The present invention relates to an improved device and method for monitoring the presence of toxic metals in workplace air, and more particularly, to real-time detection of such toxic metals.
2. Description of Related Art
Toxic metals have a negative impact on human health. The term toxic metals is used herein to include hazardous, inorganic species, such as cadmium, lead, mercury, and thallium and their soluble compounds. These compounds include any oxides, chlorides, acetates, nitrates, perchlorates, phosphates, and other salts that can be dissolved in water or in acidic solutions. The use of toxic metals in the workplace necessitates stringent precautions against accidental release. The Occupational Safety and Health Agency (OSHA) has recently reduced the permissible exposure limit of personnel to airborne cadmium particles to 5.0 micrograms/cubic meter and stipulated an action level for airborne cadmium particles at 2.5 micrograms/cubic meter. Corporations are now faced with a significant liability associated with the exposure of personnel to these materials.
At present, the most commonly used personnel monitors rely upon adsorbent or absorbent tubes and miniature air sampling pumps, followed by laboratory chemical analysis of compounds collected over long periods of time. Organizations that do not have in-house laboratories must often wait days for these analytical results. The detection limits of many of these monitors often lack the sensitivity required by OSHA and suffer from interferences that are difficult or impossible to resolve.
Prior personnel monitors for cadmium require the collection filter from a personnel air sampling pump to be sent to an off-site laboratory for analysis by skilled chemical technicians. Results of these tests are not available for several days. Personnel may experience multiple days of cadmium exposure before corrective action can be taken.
Thus, a need exists for a sensitive, real-time monitor for toxic metals such as those listed above, with detection limits that meet the new, lower OSHA exposure limits for toxic metals, to safeguard both workers and the environment.