Remediation of PAH-Contaminated Soils and Sediments: A ...

PAH in humans
The carcinogenicity of PAHs was first discovered in the mid-1930’s and gave way
to new research on the influences of PAHs on human health and the
environment. Data concerning human exposure and carcinogenicity of PAHs
have been from occupational workers exposed to PAHs during coke production,
roofing, oil refining and coal gasification (Wynder and Hoffman, 1967; Lloyd,
1971; Mazumdar et al., 1975; Hammond et al., 1976; Maclure and MacMahon,
1980). However, human exposure is not limited to inhalation, absorption or
ingestion through working environments. Nearly every person is exposed to
PAHs on a daily basis due to widespread atmospheric distribution.
As stated earlier, PAH concentrations are generally higher in the winter months
as a result of fossil fuel combustion (Harvey, 1997), making human exposure
during this time higher than in summer months. Particulate matter containing
PAHs are a major contributor to accumulation of PAHs in urban areas. A study
in Taiwan found human exposure through inhalation to be between 0.4 and 1.55
ng day -1 (Kuo et al., 2003). Menzie et al. (1992) found PAH levels to be 15-50 ng
m -3 in urban areas. In addition to particulate matter, inhalation of cigarette smoke
greatly increases human exposure to PAHs. Tobacco smoke contains more than
150 compounds in the gas phase and >2000 in the particulate phase (Harvey,
1997), making tobacco use the single greatest factor contributing to respiratory
cancers. Humans are also exposed to PAHs through ingestion and absorption.
Drinking water has been found to contain 1-10 ng PAH L -1 and high levels (10’s
of ng PAH kg -1 ) have been found in leafy vegetables, grains, fats, oils, grilled and
smoked meats (Menzie et al., 1992). It is suspected that humans inhale, ingest
and absorb 1-5 ng PAH per day from food, 0.02-3.0 ng PAH per day from air,
and 0.0002-0.12 ng PAH per day from water (Menzie et al., 1992).
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