Environmental Engineering Reference
In-Depth Information
complaints in buildings. Such research has been limited, and considerable
additional effort is required to elucidate the potential role of indoor chem-
istry and its by-products in contributing to symptoms and health complaints
in indoor environments.
III. Pesticides
Because of their known toxicity, pesticides are used to control one or more
pest organisms. As such they are unique contaminants of indoor environ-
ments. There is a limited level of understanding by users that such products
represent a potential toxic hazard to them and other building occupants,
albeit the toxic risk to users is perceived to be very low. Pesticide contami-
nation of indoor spaces can also occur inadvertently by passive transport
(track in) from lawn, garden, and agricultural applications.
Based on a 1990 National House and Garden Pesticide Use Survey, over
85% of the 66.8 million American households use pesticides, with 20% com-
mercially treated for indoor pests such as cockroaches, ants, and fleas.
Approximately 18 million households use pesticides on lawns, 8 million on
gardens, and 14 million on ornamental plants.
There are approximately 20,000 different household pesticide products,
which include 300 active ingredients and 1700 so-called inert (having no
pesticidal activity) ingredients. Such an extensive presence and use in U.S.
households, not surprisingly, results in unintended exposures and misappli-
cations. In 1993, Poison Control Centers reported over 140,000 cases of likely
pesticide exposure, with approximately 93% associated with home use.
Twenty-five percent of these had frank symptoms of pesticide poisoning;
half occurred in children under the age of six.
Pesticide products used indoors include a large variety of substances
and applications. These include biocides used by manufacturers to prevent
the biodegradation of products and by homeowners/tenants to disinfect
surfaces such as toilet bowls, nursery surfaces, etc. They also include insec-
ticides to control cockroaches, flies, ants, spiders, and moths; termiticides;
flea and tick sprays and shampoos for pets; and insecticides for both indoor
and outdoor plants (lawn, garden, and ornamentals). Fungicides are used
primarily in lawn treatments and garden sprays and, except for some bio-
cidal applications, are not commonly used indoors. Herbicides are used
exclusively for lawn care, brush control, and agricultural applications.
A. Biocides
Biocides are pesticidal compounds/formulations that are used to control the
growth of microorganisms such as bacteria (which include actinomycetes)
and fungi. They control microorganisms by killing them directly or limiting
their growth. A biocide that kills bacteria behaves like an antibiotic; it is
either bactericidal, bacteriostatic, or both.
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