Environmental Engineering Reference
In-Depth Information
Table. 6.5. Groundwater quality in Ward 1,
Epworth.
Sample
pH
Na
(mg/l)
Fe
(mg/l)
Zn
(mg/l)
Ni
(mg/l)
Co
(mg/l)
Cu
(mg/l)
Cl
(mg/l)
NO
3
(N
mg/l)
P
2
O
5
(mg/l)
Total
coli-
forms
(cfu)
Faecal
coliforms
(cfu)
Control
7.55
17.67
0.07
0.02
0.34
0.46
0.01
0.00
1.00
0.00
0
0
EPZ1
7.42
53.96
2.87
1.22
0.27
0.54
0.02
0.40
7.00
1.01 18,500
14,400
EPZ3
7.93
51.85
0.00
0.24
0.26
0.69
0.02
0.27
6.00
2.03 27,000
20,000
EPZ4
7.78
71.18
17.90
0.18
0.32
0.59
0.02
0.13
14.00
5.01 52,800
13,000
EPZ5
8.12
73.60
3.05
0.17
0.29
0.79
0.02
0.31
12.00
27.2 33,200
9,500
EPZ6
7.61
92.09
9.52
4.32
2.46
2.29
0.61
0.35
1.00
17.2
0
0
EPZ7
7.60
60.79
47.00
0.16
0.19
0.63
0.03
0.18
0.00
3.01 34,000
10,000
EPZ8
7.13
40.72
3.71
0.37
0.30
0.76
0.01
0.09
1.00
2.02
0
0
EPZ9
7.07
36.48
4.24
0.10
0.22
0.74
0.02
0.04
0.00
5.01 20,500
12,400
Mean
7.58
60.08
11.04
0.85
0.54
0.88
0.09
0.22
5.13
7.81 23,250
9,913
SD
0.37
18.39
15.56
1.45
0.78
0.58
0.21
0.13
5.57
9.38 17,781
6,911
Maximum recommended levels for different water uses
Domestic
(WHO,
1996)
---
---
---
---
0.02
---
2.00
---
50.00
---
0
0
Domestic
(DWAF,
1996)
6.0-
9.0
100
0.10
3.00
---
---
1.00
100.00
6.00
---
5
0
Livestock
(DWAF,
1996)
---
2000
10.00
20.00
1
1
1.00 1500.00 100.00
---
---
200
Crops
(DWAF,
1996)
7.5-
8.4
70
5.00
1.00
0.20
---
0.20
100.00
5.00
---
---
1
The small proportion of households served by sewerage (about 5%, as per Table 6.2)
indicates that high coliform levels in Ward 1 of Epworth are unlikely to be derived from
sewer leakages - unlike in better-serviced urban environments, e.g. city of Bulawayo as
reported by Mangore & Taigbenu (2004). Accordingly it is suggested that high coliform
levels are a result of the widespread use of pit latrines of various types - which is 95% in
Ward 1 of Epworth (Table 6.2).
The shallow depth of wells-as well as the incomplete lining of most wells-is liable to
lead to very high bacterial contamination drinking water (Conboy 1999). Gastro-
