What is in the dust inside your carpets?
Dust is a fine heterogeneous mixture of organic and
inorganic materials composed of animal fibers, vegetable
fibers, pollen, silica, silt, clay, bacteria and fungi.
Indoor environments typically accumulate large
quantities of dust, particularly in carpets.
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Poor
indoor air quality (IAQ) or indoor environmental quality (IEQ) is
typically associated with contaminated air, and samples are collected
accordingly, often yielding potentially false negative results.
Air analyses, unfortunately yield only a single snapshot in time.
In sharp contrast, dust acts as a concentrator for many chemical and
biological pollutants. Even when indoor contaminants are
undetectable in the air, they may be at significant levels in dust.
For example, the quantity of lead per square meter of carpet appears
to be the single best predictor for blood lead levels in toddlers.
The US Agency for Toxic Substances and Disease Registry (ASTDR)
estimates that 17% of pre-school children in the United States suffer
from reduced learning ability as a result of lead intake. Young
children ingest lead in floor dust through frequent hand-to mouth
contact. In fact, one study reported that children ingest 0.1 to
0.5 grams of dust per day. The necessity of monitoring and
controlling toxic compounds in air, water and food is largely accepted
and well documented. However, traditional risk models for these
routes cannot predict the toxicology of floor dust.
Other
toxic and carcinogenic contaminants that are frequently found or
linked with indoor floor dust include, benzo(a)pyrene, chlordane and
other pesticides, 2,4-D, cadmium, mycotoxins, endotoxins, dust mites,
pet allergens, allergenic and toxigenic fungi.
A 1998 Scientific American article, titled "Everyday
Exposure to Toxic Pollutants", stated "If truckloads of dust
with the same concentration of toxic chemicals as is found inside most
carpets were deposited outside, these locations would be considered
hazardous waste dumps." Floor dust may be the next smoking
gun in indoor environments.
