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Table 2 Weights and relative weights of physiochemical parameters

From: Hydrochemical characteristics of surface water and ecological risk assessment of sediments from settlements within the Birim River basin in Ghana

Parameters

Units

WHO standard (2011)

Weight (wi)

Relative weight

\({W_{i}} = \frac{{{\text{w}}_{\text{i}} }}{{\mathop \sum \nolimits_{{{\text{i}} = 1}}^{\text{n}} {\hbox{w}}_{\text{i}} }}\)

pH

 

6.5–8.5

4

0.093

TDS

mg/L

500

4

0.093

SO42−

mg/L

250

4

0.093

Ca

mg/L

75

2

0.047

Mg

mg/L

50

2

0.047

Total harness

mg/L

500

3

0.070

NO3−

mg/L

45

5

0.116

Fe

mg/L

0.3

3

0.070

Zn

mg/L

3.0

3

0.070

Na+

mg/L

200

1

0.023

K+

mg/L

12

1

0.023

Cl−

mg/L

250

5

0.116

HCO3−

mg/L

300

3

0.070

EC

μS/cm

500

3

0.070

   

\(\sum {\text{w}}_{\text{i}}\) = 43

\(\sum {\text{w}}_{\text{i}}\) = 1