Table 4.

Results for Cr, Cu, Fe, Mn, Ni and Zn from tap water and lake water samples

Element	Added (µg L−1)	Found (µg L−1)
		Tap water	Lake water
Cr	-	24.2±1.2	34.4±1.2
	50	70.6±2.1	80.2±2.1
Cu	-	30.6±1.3	40.6±1.6
	50	74.6±2.2	84.4±2.6
Fe	-	45.6±2.6	57.6±2.2
	50	88.0±2.8	102±2.8
Mn	-	35.4±1.2	42.4±1.6
	50	80.2±2.6	88.2±2.8
Ni	-	10.2±0.4	16.4±1.8
	50	56.4±1.6	60.2±2.6
Zn	-	24.0±0.4	34.2±1.8
	50	70.0±1.4	80.0±3.2

^aMean of five determinations at 95 % confidence level.