Table 1.

Distribution of 85 tubewells manganese and iron concentration categories based on Bangladesh, WHO and JECFA drinking water quality guideline.

	Category	N (%)	Mean	Min	Max	Median	IQR
Manganese (mg/L)	Minimal (0–<0.1a)	11 (13%)	0.05	0.02	0.08	0.04	0.03, 0.06
	Elevated (0.1–0.4b)	36 (42%)	0.22	0.11	0.36	0.21	0.16, 0.27
	High (>0.4)	38 (45%)	0.93	0.40	2.11	0.78	0.55, 1.07
Iron (mg/L)	Minimal (0–<0.3c)	23 (27%)	0.14	0.02	0.29	0.15	0.08, 0.20
	Elevated (0.3–2.0d)	38 (45%)	0.75	0.31	1.94	0.65	0.39, 0.98
	High (>2.0)	24 (28%)	3.72	2.10	6.20	3.56	2.97, 4.40

^aBangladesh drinking water standard^16,18; ^bWHO health-based value¹⁰; ^cWHO aesthetic cut-off¹⁰;^dJECFA provisional maximum tolerable daily intake for iron in water^17,18.