PCBs in caulk and indoor air quality
Posted on Thu, Dec 10, 2009 @ 11:07 AM
By Kristina Florentino, Environmental Compliance Specialist
An emerging environmental health issue is information published
by the Environmental Protection Agency (US EPA) that caulk containing
polychlorinated biphenyls (PCB) was used in many nonresidential
buildings, including schools, throughout the 1950s through the 1970s.
PCBs are man-made toxic chemicals that persist in the environment and
bioaccumulate in animals and humans. Exposure to PCBs can affect the
immune system, reproductive system, nervous system, and endocrine
system and is potentially cancer-causing. Caulk is used in construction
to seal gaps to make windows, door frames, masonry and joints in
buildings watertight or airtight. Before the prohibition of PCBs in all
U.S.-manufactured products in 1977, caulk was prepared with PCBs due to
the flexibility and other valuable properties of the compound such as
persistence and low reactivity. Buildings that were constructed or
renovated during this period could contain caulking with elevated
levels of these hazardous compounds.
Until recently, testing was seldom conducted for PCB levels and
there have been few studies to determine the environmental exposures to
building occupants, remediation or construction workers, or related
environmental contamination. The material will evidently deteriorate
and leach PCBs into nearby soil, concrete pads, bricks, mortar, storm
drains and potentially volatilize. Studies have shown a correlation
between PCBs in caulking and elevated levels of PCBs in indoor air and
dust, in addition to ambient soil surrounding the buildings. The
deteriorating caulk has the highest potential for creating dust
exposing occupants via inhalation. In addition to inhalation from PCBs
in the air or dust, dermal exposure may occur when a person comes in
contact with the caulk, surrounding porous materials, or
PCB-contaminated soil adjacent to buildings.
The US EPA recommends indoor air monitoring to determine if PCB
levels exceed the suggested public health levels. If testing reveals
PCB levels above these levels, the potential sources of PCBs need to be
identified. Typically testing of samples of caulk, dust, and soil is
performed. If elevated air levels of PCBs are found, it is also
recommended that the ventilation system be evaluated to determine if it
is contaminated with PCBs, since it may have been contaminated before
other sources of PCBs were removed from the building and may be
contributing to elevated air levels. Contaminated ventilation systems
need to be decontaminated along with removal of any sources of PCBs
that are found to avoid recontamination of the system.
EPA is currently researching PCB exposure related to
contaminated caulk and looking into methods for mitigating exposure and
potential risks associated with PCBs in caulk. In addition to the risk
posed by PCBs caulk can also contain as much as 20 percent asbestos,
requiring additional management during sampling and disposal.
Resources:
MA DEP PCB Q&A,
US EPA, Target Indoor Air Levels published by the EPA
Herrick,
R. F., Lefkowitz, D. J., & Weymouth, G. A. (2007). Soil
Contamination from PCB-Containing Buildings. Environmental Health
Perspectives , 115 (2), 173-175.
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