Using the equation
S ¼ b 1 Â Y1 þ b 2 Â Y2 þ b 3 Â Y3 þ b 4 Â Y4 þ b 5 Â Y5 þ b 6 Â Y6;
S ¼ 0:3130 Â 10 þ 0:2049 Â 1 þ 0:1707 Â 8 þ 0:1262 Â 8 þ 0:0993
 10 þ 0:0861  4
The hazard index of the given hazard is calculated to be 7.0475, rated Grade III.
(5) Health risk assessment of groundwater environment
(a) Hazard identification
• Preliminary screening of pollutants
According to the results of groundwater quality assessment in Table 5.6, the toxic
and harmful components detected in the groundwater of the given landfill in Hubei
Province do not reach the Grade III standards under the Quality Standards for
Groundwater (GB/T 14848–93). Considering the current situation of groundwater
utilization in the landfill site, groundwater is not used as a source of drinking water.
Based on groundwater indicators listed in Tables 5.3 and 5.4, pollutants covered by
this assessment are initially screened according to the drinking water standards
(Appendix H) for toxic and harmful components in the Guidelines for Health Risk
Assessment of Groundwater Pollution (Trial). Among them, the organic components include m-xylene and p-xylene, o-xylene, 1,3-dichlorobenzene,
1,2,4-trichlorobenzene, chloroform,
bromodichloromethane, and dibromochloromethane. The inorganic components include ammonia nitrogen, fluoride
and chloride.
• Identification of focus pollutants
The screening levels for pollutants in the given landfill are obtained by means of
HERA calculation (Table 5.7).
For these selected pollutants, the observed levels shown in Tables 5.3 and 5.4
are compared with the screening levels listed in Table 5.7. Among them, the
observed levels of 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, chloroform, bromodichloromethane and dibromochloromethane exceed the corresponding screening levels. Ammonia, fluorine and chlorine are not considered in this calculation
due to actual exposure pathways, and they are deemed to have no hazard in this
assessment. Therefore, the focus pollutants are finally identified to include
1,3-dichlorobenzene, 1,2,4-trichlorobenzene,chloroform, bromodichloromethane
and dibromochloromethane.
106
5 Application Cases
S ¼ b 1 Â Y1 þ b 2 Â Y2 þ b 3 Â Y3 þ b 4 Â Y4 þ b 5 Â Y5 þ b 6 Â Y6;
S ¼ 0:3130 Â 10 þ 0:2049 Â 1 þ 0:1707 Â 8 þ 0:1262 Â 8 þ 0:0993
 10 þ 0:0861  4
The hazard index of the given hazard is calculated to be 7.0475, rated Grade III.
(5) Health risk assessment of groundwater environment
(a) Hazard identification
• Preliminary screening of pollutants
According to the results of groundwater quality assessment in Table 5.6, the toxic
and harmful components detected in the groundwater of the given landfill in Hubei
Province do not reach the Grade III standards under the Quality Standards for
Groundwater (GB/T 14848–93). Considering the current situation of groundwater
utilization in the landfill site, groundwater is not used as a source of drinking water.
Based on groundwater indicators listed in Tables 5.3 and 5.4, pollutants covered by
this assessment are initially screened according to the drinking water standards
(Appendix H) for toxic and harmful components in the Guidelines for Health Risk
Assessment of Groundwater Pollution (Trial). Among them, the organic components include m-xylene and p-xylene, o-xylene, 1,3-dichlorobenzene,
1,2,4-trichlorobenzene, chloroform,
bromodichloromethane, and dibromochloromethane. The inorganic components include ammonia nitrogen, fluoride
and chloride.
• Identification of focus pollutants
The screening levels for pollutants in the given landfill are obtained by means of
HERA calculation (Table 5.7).
For these selected pollutants, the observed levels shown in Tables 5.3 and 5.4
are compared with the screening levels listed in Table 5.7. Among them, the
observed levels of 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, chloroform, bromodichloromethane and dibromochloromethane exceed the corresponding screening levels. Ammonia, fluorine and chlorine are not considered in this calculation
due to actual exposure pathways, and they are deemed to have no hazard in this
assessment. Therefore, the focus pollutants are finally identified to include
1,3-dichlorobenzene, 1,2,4-trichlorobenzene,chloroform, bromodichloromethane
and dibromochloromethane.
106
5 Application Cases