calculated further for the six pollutants with concentrations beyond the standard
values or highly harmful to human including nitrites, nitrates, boron, arsenic,
ammonia-nitrogen, and cyanide.
② Toxicity assessment
I. Carcinogenic toxicity
According to the findings of the International Agency for Research on Cancer
(IARC) (which is given priority) and the USEPA Integrated Risk Information
System (IRIS), the carcinogenic toxicity of the pollutants of concern was determined. The determination results of carcinogenicity are shown in Table 5.132.
Among them, five kinds of pollutants of concern (nitrites, nitrates, boron,
ammonia-nitrogen, and cyanide) are non-carcinogenic, and one pollutant of interest
(arsenic) is carcinogenic.
II. Value of toxicity parameters
The carcinogenic factor (cancer slope) and non-carcinogenic factor (reference dose)
of the pollutants of concern at the site are inquired in the database, with the results
as shown in Table 5.133.
Table 5.131 Screening of groundwater pollutants of concern in landfill
S/
N
Chemical
substance
Detected highest
concentration (mg/L)
Class III standard for
groundwater quality
1
Nitrate nitrogen
6.88
20
2
Nitrite nitrogen
0.606
0.02
3
Ammonia-nitrogen
0.038
0.2
4
Fluoride
1.15
1.0
5
Zn
<0.001
1.0
6
Copper
<0.009
1.0
7
Boron
0.238
0.05
8
As
0.0125
20
Table 5.132 Determination
of carcinogenicity of
pollutants of concern at the
site
Focus pollutants
Carcinogenicity
Nitrites
No
Nitrates
No
Boron
No
As
Yes
Ammonia-nitrogen
No
Cyanide
No
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