A. Chemical Analysis
Table -2 Results of Chemical analysis of Vegetables.
S. No
|
Parameters (mg/l)
|
Spinach
|
Okra
|
Chilies
|
Beans
|
Banana
|
1
|
Ni
|
0.41
|
3.8
|
BDL
|
2.31
|
3.114
|
2
|
Pb
|
8.2
|
0.023
|
0.2
|
0.24
|
2.132
|
3
|
Cu
|
0.3
|
0.62
|
BDL
|
0.021
|
1.414
|
4
|
Cr
|
0.027
|
0.033
|
BDL
|
BDL
|
0.78
|
5
|
Cd
|
0.031
|
0.037
|
BDL
|
BDL
|
1.68
|
6
|
Zn
|
0.22
|
3.8
|
0.039
|
3.28
|
2.54
|
BDL=below detectable limit |
Chemical Analysis of Vegetables
Present study was carried out to determine the concentration of heavy metals in vegetables grown with Korangi Drain water at a vegetable farm located in the area of Korangi, Karachi. Five vegetables which includes spinach, okra, beans, chilies, and banana grown at the farm were analyzed for Ni, Pb, Cu, Cr, Cd and Zn. Table 4 and Figure 7,8,9,10,11 indicate the results of chemical analysis of heavy metals concentration in vegetables.
Nickel The Maximum concentration of Nickel (Ni) was found in banana (3.114 mg/l), whereas the lowest was found in green Chilies which was below detectable level. In the remaining vegetables the amount of Ni was successively in the order of okra (3.8 mg/l), beans ((2.31 mg/l) and in Spinach it was found (0.410 mg/l) all of these concentrations were higher than the permissible levels recommended by WHO.
Lead The maximum concentration of Lead (Pb) was found in Spinach (8.20 mg/l), whereas the second lowest was found in Banana (2.132 mg/l), then in beans it was (0.24 mg/l), in okra the value was found (0.23 mg/l) and in chilies it was found (0.020 mg/kg) all of these concentration were higher than the permissible levels recommended by WHO.
Zinc The maximum concentration of Zinc (Zn) was found in Okra (3.80 mg/l), if we see the Table-4 the second lowest was found in Beans (3.28 mg/l), the third lowest was found in Banana (2.54 mg/l) which was within the permissible recommended levels of WHO, similarly in spinach (0.22mg/l) and in chilies (0.039 mg/l) was detected which was also within the recommended level.
Copper The maximum concentration of copper (Cu) was found in Banana (1.414 mg/l), the lowest was found in Chilies which was below the detectable level, whereas in Okra it was found (0.62 mg/l), in Spinach it was (0.300 mg/l) and in Beans it was found (0.021 mg/l).
Chromium In chromium (Cr) the maximum concentration was found in Banana (0.78 mg/l), whereas in Beans and Chilies it was below the detectable level, In Okra it was found (0.033 mg/l) and in Spinach it was (0.027 mg/l), these two parameters were detected within the recommended levels of WHO.
Cadmium The maximum level of Cadmium (Cd) was found in Banana (1.68 mg/l), whereas in Chilies and Beans it was below the detectable level (Table-4). In Okra (0.037 mg/l), and in Spinach (0.031 mg/l) it was detected above the recommended levels of WHO.
Hence, the aforementioned results indicate that all the parameters are exceeding the permissible limits of WHO expect for Cr in Spinach and Okra, and Zinc in bananas, spinach and chilies. This indicate that results are in conformity with the study of William’s (1972) in which he found that this industrial waste causes major health hazards due to the presence of heavy metals like Cu, Cd, Pb, Zn. Similarly, according to FAO (1999) found that metals such as Lead, which is accumulated in the leaves when absorbed by roots of plants and it is investigated that heavy metals concentration are found more in leafy vegetables such as lettuce. In this study we have also seen compliance in the results of our Spinach sample. Moreover, the concentrations of most studied heavy metals are detected above the permissible standard levels of WHO, hence it is a matter of great concern for the human consumers especially in this area of Korangi, Karachi.
B. Bacteriological Analysis of Vegetables
Table-3 the Results of Bacteriological Analysis
S. #
|
Parameters
MPN/100 ml x 104
|
Spinach
|
Okra
|
Green Chilies
|
Green Beans
|
Banana
|
Recommended WHO STANDARD
(mg/l)
|
1
|
Total Coliform Count (TCC)
|
>2400
|
1100
|
240
|
240
|
>2400
|
3
|
2
|
Total Faecal Coliform count (TFC)
|
>2400
|
40
|
<3
|
<3
|
>2400
|
3
|
3
|
Total Faecal Streptococci Count (TFS)
|
>2400
|
<3
|
<3
|
<3
|
210
|
3
|
The vegetables were also analyzed bacteriologically by Total Coliform Count, Total Faecal Coliform Count and Total Faecal Sreptococci. Various pathogens were identified from the surface of these vegetables. The (Table-5) shows that in Spinach amount of Total Coliform Count (TCC) was found >2400, the concentration of Total Faecal Coliform (TFC) count was also >2400 and the amount of Total faecal streptococci count (TFS) was also the same i-e >2400 in Spinach, according to the WHO recommended standards the permissible level is 3; hence it is above the permissible level. In Okra amount of Total Coliform Count (TCC) was found 1100, the concentration of Total Faecal Coliform (TFC) count was 40 and the amount of Total Faecal Streptococci count was found >3 according to the WHO recommended standards the permissible level is 3, hence it is above the permissible level.
In chilies amount of Total Coliform Count (TCC) was found 240, the concentration of Total Faecal Coliform (TFC) count was <3 and the amount of Total Faecal Streptococci Count was found <3, according to the WHO recommended standards the permissible level is 3, hence it is above the permissible level.
In Beans the amount of Total Coliform Count (TCC) was found 240, the concentration of Total Faecal Coliform (TFC) count was <3 and the amount of Total Faecal Streptococci Count was found <3, according to the WHO recommended standards the permissible level is 3; hence it is above the permissible level.
In Banana amount of Total Coliform Count (TCC) was found >2400, the concentration of Total Faecal Coliform (TFC) count was also >2400 and the amount of Total Faecal Streptococci Count was found 210, according to the WHO recommended standards the permissible level is 3, hence it is above the permissible level.
Similarly, as in chemical analysis, the concentrations of the aforementioned bacteriological parameters are also detected above the permissible standard levels of WHO, therefore it is a matter of great concern for the human consumers especially in this area of Korangi, Karachi.
A Perusal of the bacteriological analysis indicates that from human consumption point of view all the vegetables studied (spinach, okra, chilies, beans and bananas) contained higher contaminants than the safe limits established by WHO. As a rule, regarding human consumption safety standards of WHO all the bacteriological parameters TFC, TFS and TCC must be less than 3. Moreover, if any one parameter (TFC, TFS and TCC) if any one parameter exceeds 3 that vegetable becomes unfit for human consumption. Therefore, it is advisable that for consumption purpose regular monitoring should be conducted in order to detect the increasing levels of heavy metals in the vegetables.