Table 2.

Mean concentration (mg/L) of heavy metals in water samples from Nangodi and Tinga.

Study Area	Metal	n	Minimum	Maximum	Mean	SD	WHO Limit a
Nangodi (5 sites)	Mercury	30	0.001	0.191	0.038	0.001	0.010
	Arsenic	30	0.001	0.115	0.031	0.005	0.010
	Lead	30	0.005	0.791	0.250	0.008	0.010
	Zinc	30	0.005	786.0	0.034	0.001	3.000
	Cadmium	30	0.001	2.227	0.534	88.0	0.003
Tinga (7 sites)	Mercury	42	0.001	0.259	0.064	0.007	0.010
	Arsenic	42	0.001	0.003	0.002	0.001	0.010
	Lead	42	0.001	0.227	0.031	0.001	0.010
	Zinc	42	0.001	0.005	0.003	0.001	3.000
	Cadmium	42	0.002	0.071	0.023	0.008	0.003

Samples were collected from five and seven sample sites in Nangodi and Tinga, respectively (over six months), these concentrations are the general values and averages. n represents sample size; WHO limit ^a represents WHO 2008 permissible limit for drinking water.