Table 5.50 Groundwater quality test results
Items
Unit
Detection limits
Samples
1
2
3
pH
Dimensionless
–
8.06
7.86
7.89
COD
mg/L
4
26
90
90
Sulfide
mg/L
0.02
<0.02
<0.02
<0.02
Ammonia nitrogen
mg/L
–
8.73
0.154
0.351
Suspended matter
mg/L
4
14
6
6
Total nitrogen
mg/L
–
19.6
12.7
7.22
Total phosphorus
mg/L
–
0.0538
0.0400
0.0799
Hexavalent chromium
mg/L
0.004
<0.004
<0.004
<0.004
Total chromium
mg/L
0.02
<0.02
<0.02
<0.02
Total nickel
mg/L
0.006
0.0138
0.0309
0.0236
Total lead
mg/L
0.04
<0.04
<0.04
<0.04
Total vanadium
mg/L
0.01
<0.01
<0.01
<0.01
Total mercury
mg/L
0.0001
0.0002
0.0003
0.0002
Total arsenic
mg/L
0.001
0.0102
0.0204
0.0114
Benzene
lg/L
1.0
<1.0
<1.0
<1.0
Toluene
lg/L
1.0
<1.0
<1.0
<1.0
Ethylbenzene
lg/L
1.0
<1.0
<1.0
<1.0
M-/p-xylene
lg/L
1.0
<1.0
<1.0
<1.0
O-xylene
lg/L
1.0
<1.0
<1.0
<1.0
Table 5.51 Quality Standards for Groundwater (GB/T14848–2017)
Indicators
Groundwater quality standards
Grade I
Grade II
Grade III
Grade IV
Grade V
pH
6.5–8.5
5.5–6.5
8.5–9.0
<5.5,
>9.0
Ammonia nitrogen
0.02
0.10
0.50
1.50
>1.50
Permanganate index
1.0
2.0
3.0
10
>10
Hexavalent chromium
0.005
0.01
0.05
0.10
>0.10
Arsenic
0.001
0.001
0.01
0.05
>0.05
Lead
0.005
0.005
0.01
0.10
>0.10
Mercury
0.0001
0.0001
0.001
0.002
>0.002
Nickel
0.002
0.002
0.02
0.10
>0.10
Benzene
0.5
1.0
10.0
120
>120
Toluene
0.5
140
700
1400
>1400
Ethylbenzene
0.5
30.0
300
600
>600
Xylene
0.5
100
500
1000
>1000
Note The unit for water quality indicators except pH is mg/L
5.2 Northwest China
191