2.2.7 Status Quo Evaluation
(1) Groundwater quality
Based on collected data and survey results, groundwater quality is evaluated using
the single factor standard index method and the comprehensive evaluation method
proposed in the Quality Standards for Groundwater (GB/T14848–93).
Groundwater quality assessment adopts the standard index method for individual
factor evaluation. The standard index greater than 1 means that the water quality
factor has exceeded the prescribed limit, and the larger the index value, the more the
excess. For water quality factors whose evaluation criteria are fixed values, the
equation for standard index calculation is written as follows:
P i ¼
C i
C si
ð2:1Þ
Wherein P i is
the
standard
index of
water
quality
factor i,
dimensionless; C i and C si denote the monitored mass concentration and standard
mass concentration of water quality factor i respectively, expressed as mg/L.
For water quality factors (e.g. pH) whose evaluation criteria are value ranges,
the equations for standard index calculation are written as follows:
P pH ¼
7:0 À pH
7:0 À pH sd
pH 7:0
ð2:2Þ
P pH ¼
pH À 7:0
pH su À 7:0
pH [ 7:0
ð2:3Þ
Wherein P pH is the
standard
index of pH,
dimensionless; pH denotes
the monitored pH value, and pH su and pH sd represent the standard upper and lower
limits respectively.
(2) Groundwater contamination status
Groundwater pollution is assessed using the single factor index method. According
to the definition of groundwater contamination, groundwater is contaminated when
a chemical component exceeds its natural background value. A higher excess
indicates more serious contamination. Using the single factor index method proposed by China Geological Survey (2008), the degree of contamination of
groundwater samples by specific component is evaluated, with the equation written
as follows:
I ¼
C i
C 0
ð2:4Þ
30
2 Environmental Background Investigation of Groundwater …
(1) Groundwater quality
Based on collected data and survey results, groundwater quality is evaluated using
the single factor standard index method and the comprehensive evaluation method
proposed in the Quality Standards for Groundwater (GB/T14848–93).
Groundwater quality assessment adopts the standard index method for individual
factor evaluation. The standard index greater than 1 means that the water quality
factor has exceeded the prescribed limit, and the larger the index value, the more the
excess. For water quality factors whose evaluation criteria are fixed values, the
equation for standard index calculation is written as follows:
P i ¼
C i
C si
ð2:1Þ
Wherein P i is
the
standard
index of
water
quality
factor i,
dimensionless; C i and C si denote the monitored mass concentration and standard
mass concentration of water quality factor i respectively, expressed as mg/L.
For water quality factors (e.g. pH) whose evaluation criteria are value ranges,
the equations for standard index calculation are written as follows:
P pH ¼
7:0 À pH
7:0 À pH sd
pH 7:0
ð2:2Þ
P pH ¼
pH À 7:0
pH su À 7:0
pH [ 7:0
ð2:3Þ
Wherein P pH is the
standard
index of pH,
dimensionless; pH denotes
the monitored pH value, and pH su and pH sd represent the standard upper and lower
limits respectively.
(2) Groundwater contamination status
Groundwater pollution is assessed using the single factor index method. According
to the definition of groundwater contamination, groundwater is contaminated when
a chemical component exceeds its natural background value. A higher excess
indicates more serious contamination. Using the single factor index method proposed by China Geological Survey (2008), the degree of contamination of
groundwater samples by specific component is evaluated, with the equation written
as follows:
I ¼
C i
C 0
ð2:4Þ
30
2 Environmental Background Investigation of Groundwater …