To determine the predominant exposure pathways leading to
the potential non-cancer risks, Crwas taken as an example to reveal the contribution of each pathway to the total HI. As shown in the contribution from food ingestion and PM10 inhalation to the potential non-carcinogenic health risk was nearly comparable, accounting
for 56.18% and 43.82% to the total Cr HI, respectively.
Different from which indicated that food ingestion was the
largest contributor to the children's Cr ADD, food ingestion and
PM10 inhalation were both predominant contributors to the Cr HI.
This result revealed that slight environmental pollution still had a
great possibility to pose potential adverse health effects to human
beings if the RfD value is low. Whereas, though the environment
was heavily polluted by contaminants, detrimental effects to human
would be unlikely to happen due to the low intake. Except
from the neglected contribution from ingestion through water and
dust/soil and inhalation through dust and soil, the harmful health
effects through dermal contact were regarded to be acceptable.
Among the PM10 inhalation, the outdoor air was the larger
contributor, which accounted for 67.47%. This could be mainly
attributed to that the Cr in indoor air was less polluted compared to
that of outdoor. In addition, home indoor air contributed less than
that of school indoor air. The latter was 1.5 times higher than the
former. One explanation is that the school was surrounded by
traffics and typical urban activities, and thus school interior air was
more polluted than the home interior air. On the basis of home
investigation, the dwelling houses of most volunteer participants
were situated in the residential area with little traffic, which might