Table 3.

Showing the levels (ppb or micrograms per liter) of heavy metals (Hg, Pb, Cr, Cd, Tl, and Ni) for the HNO₃ digested. water samples (waste and clean) obtained from different sites.

Site of samples collection	Sample code	Heavy metals analyzed (ppb or µg/L)
		Hg (0.1)a	Pb (0.1)	Cr (0.5)	Cd (0.05)	Tl (0.01)	Ni (0.2)
Waste water:
Tetrapak	A2	<0.1	9.5	0.7	0.09	<0.01	1.7
Chief’s Camp	B3a	<0.1	29.5	2.9	0.08	0.04	2.1
Chief’s Camp	B3b	<0.1	28.2	2.7	0.11	0.09	2.6
Railways Lower	C2	<0.1	8.3	9.8	0.17	0.08	21.1
Railways Upper	D2	<0.1	6.9	2.1	0.09	0.08	6.1
Davis & Shirtliff	E2	<0.1	24.2	1.9	0.13	0.05	2.6
Kartasi	F3	<0.1	17.3	1.4	0.08	0.03	6.5
Sinai	G3	<0.1	0.4	50.7	<0.05	0.03	<0.2
Donholm	H2	<0.1	13.5	0.9	<0.05	0.02	1.7
Mean concentration ± SE (ppb)		<0.1 ± 0.00	15.31 ± 3.39	8.12 ± 5.40	0.09 ± 0.01	0.05 ± 0.009	4.96 ± 2.13
Mean concentration (ppm or mg/l)		<0.0001	0.01531	0.00812	0.00009	0.00005	0.00496
Tap water (control) - ppb:
Roysambu (House)b	I3	< 0.1	1.6	0.6	<0.05	<0.01	<0.2

^aThe value in bracket shows the method detection limit (MDL) measured in ppb. ^bTap water samples were acidified with HNO₃ before metal analysis.