• Direct exposure pathways: ingestion of groundwater (drinking water supply), and
inhalation inside and outside buildings
• Indirect exposure pathways: ingestion and contact through bathing and recreational activities
By measuring contaminants in soil gas (soil-gas well), and in ambient air (inside
and outside the building), it was possible to determine contamination at the source as
well as characterize the concentrations in the exposed media. Because domestic fuel
has moderate volatility, concentrations of monoaromatic compounds (BTEX), Total
Petroleum Hydrocarbons (TPH), and Polycyclic Aromatic Hydrocarbons (PAH)
were compatible with an industrial use beneath the site and a sensible use downstream for domestic use. Therefore, air contamination was not the main priority
within the Management Plan.
As for aqueous media, the groundwater was more vulnerable than the surface
water (because of flow rate differences). Petroleum products were analyzed and
compared with drinking water values against specific parameters [benzene, PAH
(6)]. A predictive Residual Risk Assessment (RRA) was performed on the other
compounds. Immediately downstream of the building, the contents were not
compatible with use as drinking water. About 40 m
3 of free product were
discovered. The close vicinity of the drinking water supply, and observed levels of
groundwater concentration imply that groundwater management should be the key
priority at this site. The volume of contaminated soil was estimated to range from
500 to 800 m
3 .
Fig. 2.26 Conceptual model of the site (Colombano and Hiez 2009)
2 Free Product Recovery of Non-aqueous Phase Liquids in Contaminated Sites:. . .
103
inhalation inside and outside buildings
• Indirect exposure pathways: ingestion and contact through bathing and recreational activities
By measuring contaminants in soil gas (soil-gas well), and in ambient air (inside
and outside the building), it was possible to determine contamination at the source as
well as characterize the concentrations in the exposed media. Because domestic fuel
has moderate volatility, concentrations of monoaromatic compounds (BTEX), Total
Petroleum Hydrocarbons (TPH), and Polycyclic Aromatic Hydrocarbons (PAH)
were compatible with an industrial use beneath the site and a sensible use downstream for domestic use. Therefore, air contamination was not the main priority
within the Management Plan.
As for aqueous media, the groundwater was more vulnerable than the surface
water (because of flow rate differences). Petroleum products were analyzed and
compared with drinking water values against specific parameters [benzene, PAH
(6)]. A predictive Residual Risk Assessment (RRA) was performed on the other
compounds. Immediately downstream of the building, the contents were not
compatible with use as drinking water. About 40 m
3 of free product were
discovered. The close vicinity of the drinking water supply, and observed levels of
groundwater concentration imply that groundwater management should be the key
priority at this site. The volume of contaminated soil was estimated to range from
500 to 800 m
3 .
Fig. 2.26 Conceptual model of the site (Colombano and Hiez 2009)
2 Free Product Recovery of Non-aqueous Phase Liquids in Contaminated Sites:. . .
103