Dissolved Concentrations, Sources, and Risk Evaluation of Selected Metals in Surface Water from Mangla Lake, Pakistan

Table 3

Descriptive statistics for selected metals and water quality parameters in water samples in comparison with national/international standards (𝑛=150).

	Summer					Winter					Water quality guidelines
	Range	Mean	Median	SD	Skew	Range	Mean	Median	SD	Skew	WHO	USEPA	PakEPA
Ca (mg/L)	14–48	43	44	5.5	−4.8	41–169	79	71	24	2.4	100	—	200
Cd (mg/L)	<0.01–0.10	0.03	0.03	0.03	1.1	<0.01–0.08	0.03	0.02	0.03	0.81	0.003	0.005	0.001
Co (mg/L)	0.01–0.50	0.25	0.24	0.12	0.12	0.01–0.41	0.16	0.13	0.12	0.92	0.04	—	—
Cr (mg/L)	<0.01–0.21	0.08	0.07	0.05	0.65	0.01–0.19	0.07	0.07	0.04	0.93	0.05	0.1	0.05
Cu (mg/L)	<0.01–0.05	0.02	0.01	0.01	0.71	<0.01–0.06	0.02	0.02	0.02	0.67	2.0	1.3	2.0
Fe (mg/L)	0.02–0.33	0.15	0.15	0.07	0.25	<0.01–0.38	0.13	0.14	0.09	0.53	0.3	0.3	—
K (mg/L)	1.2–1.6	1.3	1.4	0.08	0.32	0.61–2.0	1.3	1.2	0.31	0.75	12	—	—
Li (mg/L)	<0.01–0.03	0.01	0.01	0.01	1.0	<0.01–0.02	0.01	0.01	<0.01	0.02	—	—	—
Mg (mg/L)	3.0–3.7	3.4	3.4	0.18	0.07	3.8–8.4	4.9	4.1	1.3	1.0	50	—	—
Mn (mg/L)	<0.01–0.05	0.01	0.01	0.01	1.4	<0.01–0.06	0.02	0.01	0.01	1.4	0.1	0.05	0.5
Na (mg/L)	2.1–2.8	2.4	2.4	0.21	0.41	3.4–35	6.8	4.2	6.5	3.5	200	—	—
Ni (mg/L)	0.01–0.42	0.13	0.11	0.09	1.3	0.01–0.29	0.11	0.10	0.07	0.36	0.07	0.7	0.02
Pb (mg/L)	0.02–1.5	0.38	0.24	0.32	1.5	<0.01–2.2	0.34	0.21	0.41	3.0	0.01	0.015	0.05
Sr (mg/L)	0.07–0.29	0.19	0.21	0.07	−0.43	0.11–0.39	0.22	0.22	0.06	0.41	—	—	—
Zn (mg/L)	<0.01–0.07	0.03	0.03	0.02	0.10	<0.01–0.08	0.03	0.03	0.02	0.65	3.0	5.0	5.0
Cl^− (mg/L)	9.9–15	11	9.9	1.7	0.83	5.0–15	8.8	8.7	2.8	0.76	250	250	250
DO (mg/L)	3.6–4.9	4.3	4.5	0.38	−0.92	3.6–5.0	4.4	4.6	0.42	−0.29	—	—	—
EC (𝜇S/cm)	131–159	140	139	5.6	1.2	180–477	250	214	69	2.0	1500	—	—
pH	7.6–8.2	8.0	8.1	0.16	−1.2	7.4–8.3	7.8	7.9	0.33	−0.04	6.5–8.5	6.5–8.5	6.5–8.5
𝑇 (°C)	37–38	38	38	0.08	0.26	10–13	11	11	0.41	3.0	—	—	—
TA (mg CaCO3/L)	58–290	144	131	53	0.81	30–195	94	75	42	0.82	200	—	—
TDS (mg/L)	65–80	70	69	2.8	1.2	91–238	125	107	34	1.9	1000	500	1000
Reference	Present study										[27]	[29]	[30]