01/13/2011

Understanding Potential Exposure Sources of Perfluorinated Carboxylic Acids in the Workplace

This paper integrates perspectives from analytical chemistry, environmental
engineering, and industrial hygiene to better understand how workers may be
exposed to perfluorinated carboxylic acids when handling them in the workplace
in order to identify appropriate exposure controls. Due to the dramatic
difference in physical properties of the protonated acid form and the anionic
form, this family of chemicals provides unique industrial hygiene challenges.
Workplace monitoring, experimental data, and modeling results were used to
ascertain the most probable workplace exposure sources and transport mechanisms
for perfluorooctanoic acid (PFOA) and its ammonium salt (APFO). PFOA is
biopersistent and its measurement in the blood has been used to assess human
exposure since it integrates exposure from all routes of entry. Monitoring
suggests that inhalation of airborne material may be an important exposure
route. Transport studies indicated that, under low pH conditions, PFOA, the
undissociated (acid) species, actively partitions from water into air. In
addition, solid-phase PFOA and APFO may also sublime into the air. Modeling
studies determined that contributions from surface sublimation and loss from
low pH aqueous solutions can be significant potential sources of workplace
exposure. These findings suggest that keeping surfaces clean, preventing
accumulation of material in unventilated areas, removing solids from waste
trenches and sumps, and maintaining neutral pH in sumps can lower workplace
exposures.


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AplusA-online.de - Source: Annals of Occupational Hygiene