Assessment of Levels, Speciation, and Toxicity of Trace Metal Contaminants in Selected Shallow Groundwater Sources, Surface Runoff, Wastewater, and Surface Water from Designated Streams in Lake Victoria Basin, Uganda

Table 12

Percentage composition of metal ions in aqueous media as determined by speciation studies of selected surface water samples from streams in Lake Victoria basin, Uganda.

Sampling site	Ni^2+	Cu^2+	Zn^2+	Cd^2+	Pb^2+	Al^3+	Mn^2+	Fe^3+
Jinja Landfill leachate
Bound to DOM	92.5	100	96.3	87.7	99.9	46.9	24.5	100
Free ion	7.0	—	2.9	5.2	—	—	65.5	—
Inorganic	0.5	—	0.8	7.1	0.01	54.1	10.0	—
Dominant ion	FANi^+	FA2CuOH	FA2Zn	FA2Cd	FA2Pb	Al(OH)4^−	Mn^2+	FA2FeOH
Kiteezi Landfill leachate
Bound to DOM	96.5	100	99.4	97.5	100	13.5	37.1	100
Free ion	3.4	—	0.4	0.9	—	—	61.9	—
Inorganic	0.1	—	0.2	1.8	—	86.5	1.0	—
Dominant ion	FANi^+	FA2CuOH	FA2Zn	FA2Cd	FA2Pb	Al(OH)4^−	Mn^2+	FA2FeOH
Lubigi Channel
Bound to DOM	58.5	98.3	35.1	31.8	97.7	4.7	8.2	97.5
Free ion	40.0	0.7	59.8	58.4	1.6	—	86.3	—
Inorganic	1.5	1.0	6.1	10.8	1.3	95.3	5.5	2.4
Dominant ion	Ni^2+	FA2Cu	Zn^2+	Cd^2+	FA2Pb	Al(OH)4^−	Mn^2+	FA2FeOH
Nakivubo Channel
Bound to DOM	9.2	47.1	3.2	2.8	42.6	0.5	0.9	45.7
Free ion	86.9	27.6	87.9	76.6	38.7	—	90.3	—
Inorganic	3.9	25.3	8.9	20.6	18.7	99.5	8.8	54.3
Dominant ion	Ni^2+	FA2Cu	Zn^2+	Cd^2+	FA2Pb	Al(OH)4^−	Mn^2+	Fe(OH)3