Table 1.

Mean, median, range and standard deviation of measured chemical parameters in villages of Poldasht city.

Month	Free residual color		pH		Turbidity
	Mean ± SD	Median (range)	Mean ± SD	Median (range)	Mean ± SD	Median (range)
September	0.25 ± 0.28	0.2 (0 to 1)	7.6 ± 0.1	7.6 (7.4 to 7.6)	0.31 ± 0.13	0.29 (0.12 to 0.54)
October	0.12 ± 0.2	0 (0 to 0.8)	7.6 ± 0.1	7.6 (7.4 to 7.6)	0.27 ± 0.07	0.26 (0.1 to 0.42)
November	0.28 ± 0.27	0.3 (0 to 1)	7.5 ± 0.1	7.6 (7.4 to 7.6)	0.55 ± 0.69	0.34 (0.12 to 3.5)
December	0.2 ± 0.27	0 (0 to 1)	7.5 ± 0.1	7.5 (7.4 to 7.6)	0.32 ± 0.06	0.32 (0.1 to 0.41)
January	0.44 ± 0.53	0.3 (0 to 2)	7.5 ± 0.1	7.6 (7.4 to 7.8)	0.45 ± 0.03	0.46 (0.4 to 0.49)
February	0.21 ± 0.34	0 (0 to 2)	7.6 ± 0.1	7.6 (7.4 to 7.8)	0.67 ± 0.56	0.5 (0.35 to 2.64)
March	0.34 ± 0.37	0.3 (0 to 1.5)	7.6 ± 0.1	7.6 (7.4 to 7.8)	0.45 ± 0.13	0.41 (0.21 to 0.66)
April	0.21 ± 0.4	0 (0 to 2)	7.5 ± 0.1	7.6 (7.4 to 7.6)	0.77 ± 0.58	0.61 (0.31 to 2.45)
May	0.34 ± 0.52	0.2 (0 to 2)	7.5 ± 0.1	7.6 (7.2 to 7.8)	0.46 ± 0.29	0.36 (0.19 to 1.76)
june	0.41 ± 0.53	0.3 (0 to 2)	7.5 ± 0.2	7.5 (7 to 8.2)	0.51 ± 0.08	0.49 (0.39 to 0.68)
July	0.22 ± 0.26	0.2 (0 to 0.8)	7.6 ± 0.1	7.6 (7.4 to 7.8)	0.4 ± 0.05	0.39 (0.31 to 0.54)
August	0.42 ± 0.57	0.2 (0 to 2)	7.5 ± 0.2	7.6 (7 to 7.6)	0.42 ± 0.04	0.43 (0.35 to 0.48)
P-value†	0.005		0.021		<0.001

^†Based on Linear Mixed model.