Water quality index for assessment of drinking groundwater purpose case study: area surrounding Ismailia Canal, Egypt

Journal of Engineering and Applied Science

Table 2 Limits of WHO, Egyptian standards and assigned weight, and relative for chemical parameters

Parameters	WHO desirable limit (mg/l) (a)	WHO allowable limit (mg/l) (b)	Egypt limit (mg/l)	Weight (wi)	Relative weight (Wi)
Parameters	WHO desirable limit (mg/l) (a)	WHO allowable limit (mg/l) (b)	Egypt limit (mg/l)	(wi)	(Wi)
EC	1000 (mmhos)	1500 (mmhos)	–	5	0.082
TDS	500	1000	1000	4	0.066
pH	6.5–8.5	8.5	6.5–8.5	2	0.033
K	10	12	12	5	0.082
Na	200	200	200	5	0.082
Ca	75	75	200	3	0.049
Mg	50	50	150	5	0.082
HCO₃	250	500	–	2	0.033
_CO3	100	100	–	2	0.033
Cl	250	250	250	5	0.082
SO₄	250	250	250	4	0.066
Fe	0.3	1	0.3	2	0.033
Mn	0.05	0.1	0.4	2	0.033
Cd	0.005	0.1	0.003	2	0.033
Zn	5	5	3	2	0.033
Pb	0.01	0.01	0.01	2	0.033
Cr	0.05	0.05	0.05	2	0.033
Co	0.05	0.05	1	2	0.033
Cu	1	2	2	2	0.033
Al	0.2	0.2	0.2	2	0.033
				∑w_{i = 61}	∑W_{i = 1}