– Toxicity values
The toxicity values (reference doses) are all obtained from the aforementioned
databases, as shown in Table 5.54.
• Exposure assessment
– Types of land use
In this health risk assessment, the site is categorized into sensitive land, considering
the way of groundwater utilization in the site and the surrounding area.
• Source-pathway-receptor analysis
– Pollution sources
Based on the assessment of human health risks of contaminated groundwater, the
source of pollution is: contaminated groundwater from oil-contaminated sites.
Since this study aims to assess the human health risks of groundwater in contaminated sites, the pollution sources are deemed to be contaminated groundwater
in the oil-contaminated site.
– Pollutant migration pathways
Pollutants penetrate into the groundwater through the soil and contaminate the
groundwater in the site. Further, groundwater pollutants migrate, transform, and
spread as groundwater flows.
– Receptors
During the use of the site, groundwater pollutants will pose hazards to the exposed
residents in the surrounding areas. According to the site use and the surrounding
population, residents in the vicinity of the site are identified as sensitive receptors.
• Exposure pathway analysis
Receptors in a polluted environment may be exposed through such pathways as
groundwater intake and outdoor and indoor inhalation of vapor from groundwater.
Groundwater in this site does not support drinking, so the oral pathway is excluded.
According to the results of HERA calculation that consider pollutant characteristics,
receptors will not be exposed through outdoor and indoor inhalation of vapor from
groundwater. In other words, there is no exposure pathway for pollutants in the
groundwater of the study site to threaten human health.
(b) Conclusions
Based on the screening, toxicity analysis and exposure assessment of groundwater
pollutants in the site, it is concluded that there are no pathways of exposure to
hazardous and toxic pollutants that undermine human health. In other words,
groundwater pollutants in the site will not lead to risk in human health.
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195
The toxicity values (reference doses) are all obtained from the aforementioned
databases, as shown in Table 5.54.
• Exposure assessment
– Types of land use
In this health risk assessment, the site is categorized into sensitive land, considering
the way of groundwater utilization in the site and the surrounding area.
• Source-pathway-receptor analysis
– Pollution sources
Based on the assessment of human health risks of contaminated groundwater, the
source of pollution is: contaminated groundwater from oil-contaminated sites.
Since this study aims to assess the human health risks of groundwater in contaminated sites, the pollution sources are deemed to be contaminated groundwater
in the oil-contaminated site.
– Pollutant migration pathways
Pollutants penetrate into the groundwater through the soil and contaminate the
groundwater in the site. Further, groundwater pollutants migrate, transform, and
spread as groundwater flows.
– Receptors
During the use of the site, groundwater pollutants will pose hazards to the exposed
residents in the surrounding areas. According to the site use and the surrounding
population, residents in the vicinity of the site are identified as sensitive receptors.
• Exposure pathway analysis
Receptors in a polluted environment may be exposed through such pathways as
groundwater intake and outdoor and indoor inhalation of vapor from groundwater.
Groundwater in this site does not support drinking, so the oral pathway is excluded.
According to the results of HERA calculation that consider pollutant characteristics,
receptors will not be exposed through outdoor and indoor inhalation of vapor from
groundwater. In other words, there is no exposure pathway for pollutants in the
groundwater of the study site to threaten human health.
(b) Conclusions
Based on the screening, toxicity analysis and exposure assessment of groundwater
pollutants in the site, it is concluded that there are no pathways of exposure to
hazardous and toxic pollutants that undermine human health. In other words,
groundwater pollutants in the site will not lead to risk in human health.
5.2 Northwest China
195