3.1 Physical and chemical composition of packaged groundwater
The physical and chemical parameters of the packaged/sachet groundwater samples are presented in Table 1. The pH of the packaged/sachet water samples varied from 6.88 ± 0.12 (Makun-Sagamu) to 8.10 ± 0.51 (Isolu). These pH values were within the permissible range of 6.5–8.5 for drinking water (WHO, 2017). The sachet water samples from the Abeokuta metropolis were slightly alkaline, while those from Makun-Sagamu were slightly acidic. Therefore, the pH values of sachet water are comparable to the levels determined in groundwater samples from major cities in the southwestern part of Nigeria (Taiwo, 2012).
There were no significant variations (p > 0.05) in the levels of electrical conductivity (EC) observed in sachet water at different sampling sites, except in the Iberekodo site (Abeokuta). EC ranged from 31.40 ± 12.75 (Makun-Sagamu) to 144.80 ± 77.48 µS/cm (Iberekedo). Although the EC values in water samples were lower than the permissible standard of 1000 µS/cm stipulated by the WHO (WHO, 2004), but level observed in Iberekodo packaged/sachet water was four times higher than those from other sampling sites. The past study by Shiaka et al. (2021) observed a higher value of EC in sachet water from Zamfara, the northern part of Nigeria.
The highest level of total dissolved solids (TDS, 72.60 ± 38.79 mg/L) was also observed in Iberekodo sachet water, while the lowest value (11.85 ± 5.28 mg/L) was determined in Obantoko. Total suspended solids (TSS) values observed in packaged/sachet water were usually very low similar to those reported by Opafola et al. (2020) in sachet water samples from a tertiary institution in Nigeria. The concentrations of TDS, hardness, alkalinity, and chloride were also observed at the highest concentrations in Iberekodo sachet water. The levels of these parameters were within the acceptable limits in drinking water. This indicates possible good quality for these packaged groundwater samples similar to the values reported by Ojekunle et al. (2020) in groundwater from Sagamu.
|
N = 140
|
N
|
Mean
|
SD
|
Minimum
|
Maximum
|
WHO (2017)
|
Table 1
Physical and chemical parameters of packaged/sachet water
pH
|
Iberekodo
|
20
|
7.40b
|
0.32
|
6.92
|
7.84
|
6.5–8.5
|
|
Obada
|
20
|
7.70c
|
0.19
|
7.45
|
8.01
|
|
|
Obantoko
|
20
|
7.65c
|
0.24
|
7.43
|
8.13
|
|
|
Asero
|
20
|
7.46b
|
0.26
|
7.13
|
8.04
|
|
|
Camp-Osiele
|
20
|
7.56bc
|
0.25
|
7.29
|
8.00
|
|
|
Isolu
|
20
|
8.10d
|
0.51
|
7.32
|
9.53
|
|
|
Makun-Sagamu
|
20
|
6.88a
|
0.12
|
6.65
|
7.12
|
|
EC
|
Iberekodo
|
20
|
144.80c
|
77.48
|
32.00
|
256.00
|
1000*
|
(µS/cm)
|
Obada
|
20
|
39.15a
|
24.36
|
23.00
|
84.00
|
|
|
Obantoko
|
20
|
23.85a
|
10.57
|
7.00
|
37.00
|
|
|
Asero
|
20
|
37.10a
|
16.01
|
16.00
|
61.00
|
|
|
Camp-Osiele
|
20
|
36.95a
|
3.39
|
26.00
|
42.00
|
|
|
Isolu
|
20
|
61.80b
|
44.22
|
21.00
|
132.00
|
|
|
Makun-Sagamu
|
20
|
31.40a
|
12.75
|
21.00
|
55.00
|
|
TDS
|
Iberekodo
|
20
|
72.60c
|
38.79
|
16.00
|
128
|
600
|
(mg/L)
|
Obada
|
20
|
19.55a
|
12.20
|
11.00
|
42.00
|
|
|
Obantoko
|
20
|
11.85a
|
5.28
|
3.00
|
19.00
|
|
|
Asero
|
20
|
18.60a
|
8.03
|
8.00
|
31.00
|
|
|
Camp-Osiele
|
20
|
18.50a
|
1.79
|
13.00
|
21.00
|
|
|
Isolu
|
20
|
31.60b
|
22.53
|
11.00
|
67.00
|
|
|
Makun-Sagamu
|
20
|
15.70a
|
6.33
|
11.00
|
28.00
|
|
TSS
|
Iberekodo
|
20
|
0.01a
|
0.00
|
0.00
|
0.02
|
|
(mg/L)
|
Obada
|
20
|
0.12b
|
0.19
|
0.00
|
0.66
|
|
|
Obantoko
|
20
|
0.00a
|
0.00
|
0.00
|
0.02
|
|
|
Asero
|
19
|
0.00a
|
0.01
|
0.00
|
0.02
|
|
|
Camp-Osiele
|
16
|
0.02a
|
0.01
|
0.00
|
0.03
|
|
|
Isolu
|
20
|
0.00a
|
0.01
|
0.00
|
0.06
|
|
|
Makun-Sagamu
|
20
|
0.05a
|
0.03
|
0.00
|
0.13
|
|
Hardness
|
Iberekodo
|
20
|
74.00ab
|
47.32
|
0.00
|
130.00
|
200.00
|
(mg/L)
|
Obada
|
20
|
5.00a
|
9.03
|
0.00
|
25.00
|
|
|
Obantoko
|
20
|
18.30ab
|
29.42
|
0.00
|
135.00
|
|
|
Asero
|
20
|
24.65ab
|
10.99
|
2.00
|
42.00
|
|
|
Camp-Osiele
|
20
|
29.75ab
|
14.30
|
15.00
|
68.00
|
|
|
Isolu
|
20
|
84.69b
|
266.51
|
0.70
|
1215.00
|
|
|
Makun-Sagamu
|
20
|
11.25a
|
4.25
|
5.00
|
20.00
|
|
Alkalinity
|
Iberekodo
|
20
|
18.50c
|
6.51
|
5.00
|
30.00
|
120.00
|
(mg/L)
|
Obada
|
20
|
5.25a
|
2.91
|
2.50
|
10.00
|
|
|
Obantoko
|
20
|
11.18b
|
3.73
|
5.50
|
17.50
|
|
|
Asero
|
20
|
7.60a
|
3.90
|
4.50
|
20.00
|
|
|
Camp-Osiele
|
20
|
6.50a
|
3.13
|
2.50
|
15.00
|
|
|
Isolu
|
20
|
11.23b
|
10.25
|
0.00
|
40.00
|
|
|
Makun-Sagamu
|
20
|
6.38a
|
3.08
|
1.00
|
12.50
|
|
Chloride
|
Iberekodo
|
20
|
53.50c
|
20.53
|
30.00
|
80.00
|
250.00
|
(mg/L)
|
Obada
|
20
|
10.38a
|
1.22
|
10.00
|
15.00
|
|
|
Obantoko
|
20
|
10.33a
|
4.12
|
2.50
|
17.50
|
|
|
Asero
|
20
|
16.00a
|
3.66
|
10.00
|
25.00
|
|
|
Camp-Osiele
|
20
|
16.08a
|
2.84
|
12.50
|
24.00
|
|
|
Isolu
|
20
|
30.69b
|
25.27
|
1.50
|
125.00
|
|
|
Makun-Sagamu
|
20
|
8.77a
|
2.53
|
5.50
|
17.50
|
|
SD-Standard deviation, dissimilar alphabets along same column are statistically different at p < 0.05, according to Duncan Multiple Range Test |
3.2 Concentrations of major elements of packaged groundwater
The data of major elements observed in packaged/sachet groundwater samples are shown in Table 2. The levels of Ca were generally less than the permissible standard of 75 mg/L, except in Obantoko samples (86.54 ± 37.34 mg/L). The calcium content of sachet water purchased from this site was significantly higher (p < 0.05) than those collected from other sites, except Makun-Sagamu.
|
N = 56
|
N
|
Mean
|
SD
|
Minimum
|
Maximum
|
WHO (2011)
|
Table 2
Major elements in packaged/sachet groundwater samples
Ca
|
Iberekodo
|
8
|
12.88a
|
3.76
|
8.65
|
17.81
|
75
|
(mg/L)
|
Obada
|
8
|
9.47a
|
14.16
|
0.06
|
35.22
|
|
|
Obantoko
|
8
|
86.54c
|
37.34
|
38.34
|
128.45
|
|
|
Asero
|
8
|
36.31ab
|
6.66
|
27.44
|
42.36
|
|
|
Camp-Osiele
|
8
|
24.12a
|
23.64
|
8.13
|
59.15
|
|
|
Isolu
|
8
|
26.22a
|
19.23
|
8.43
|
52.83
|
|
|
Makun-Sagamu
|
8
|
62.78bc
|
26.99
|
23.61
|
83.86
|
|
K
|
Iberekodo
|
8
|
4.68a
|
2.04
|
2.33
|
6.95
|
12
|
(mg/L)
|
Obada
|
8
|
4.54a
|
2.28
|
2.02
|
8.35
|
|
|
Obantoko
|
8
|
3.05a
|
1.03
|
1.87
|
4.38
|
|
|
Asero
|
8
|
20.36b
|
11.15
|
7.16
|
30.46
|
|
|
Camp-Osiele
|
8
|
4.04a
|
3.62
|
1.8
|
9.42
|
|
|
Isolu
|
8
|
9.26a
|
4.5
|
5.75
|
15.65
|
|
|
Makun-Sagamu
|
8
|
5.58a
|
1.9
|
3.33
|
7.4
|
|
Mg
|
Iberekodo
|
8
|
0.30a
|
0.14
|
0.11
|
0.41
|
50
|
(mg/L)
|
Obada
|
8
|
3.12a
|
3.64
|
0.01
|
10.18
|
|
|
Obantoko
|
8
|
4.93a
|
3.94
|
1.57
|
10.14
|
|
|
Asero
|
8
|
4.22a
|
2.67
|
0.92
|
7.39
|
|
|
Camp-Osiele
|
8
|
0.25a
|
0.11
|
0.12
|
0.36
|
|
|
Isolu
|
8
|
12.33b
|
9.9
|
3.15
|
22.35
|
|
|
Makun-Sagamu
|
8
|
7.43ab
|
6.07
|
2.83
|
15.97
|
|
Na
|
Iberekodo
|
8
|
7.53a
|
3.37
|
3.62
|
11.18
|
50
|
(mg/L)
|
Obada
|
8
|
36.05b
|
29.5
|
5.15
|
64
|
|
|
Obantoko
|
8
|
15.80a
|
11.16
|
6.58
|
31.28
|
|
|
Asero
|
8
|
34.91b
|
42.72
|
4.63
|
97.65
|
|
|
Camp-Osiele
|
8
|
5.78a
|
2.54
|
2.58
|
8.02
|
|
|
Isolu
|
8
|
15.46a
|
1.71
|
13.82
|
17.43
|
|
|
Makun-Sagamu
|
8
|
9.27a
|
2.21
|
6.22
|
10.89
|
|
SD-Standard deviation, dissimilar alphabets along same column are statistically different at p < 0.05, according to Duncan Multiple Range Test |
K indicated the highest concentration (20.36 ± 11.15 mg/L) in Asero sachet water above the WHO permissible level of 12 mg/L (WHO, 2011). The highest significant level of Mg was established in sachet water purchased from Isolu. However, the Mg values in sachet water from all the sites generally fell within the acceptable limit of 50 mg/L (WHO, 2011). Although, the highest significant level of Na (36.05 ± 29.5 mg/L) was observed in Obada sachet water, but was not statistically different from Asero samples (34.91 ± 42.47 mg/L). Mg and Na had values lower than the permissible limits set by the WHO. A previous study by Ndur et al. (2015) observed lower concentrations of Ca, K, and Mg, and higher Na levels in sachet water samples collected from Tarwa, Ghana.
3.3 Trace metal concentrations of package groundwater
Table 3 presents the levels of trace metals determined in packaged/sachet water samples. The highest levels of Co and Cu were observed in sachet water from Asero. Unfortunately, there is no permissible standard provided for Co in drinking water by the WHO. Therefore, Co may not be a threat to the packaged/sachet water samples in the study area, despite the high mean value of 347.2 ± 231.5 µg/L established in Asero samples. The Co levels observed in water samples were generally higher than the level of less than 2 µg/L that is often observed in drinking water (ATSDR, 2004). Similar to the present study, Atashi et al. (2009) reported Co that varied between 172 and 204 µg/L in groundwater from Zahedan city in Iran.
The Cu levels in all the packaged/sachet water samples were within the permissible standard of the WHO (WHO, 2011). Samples from Makun-Sagamu had the greatest concentrations of Fe, Ni, and Zn. The average amount of Fe in Obantoko and Makun-Sagamu samples was higher than the acceptable limit of 300 µg/L (WHO, 2011); similar to the past study by Naabil et al. (2014) in sachet water from Bolgatanga Municipality of Ghana.
|
N = 56
|
N
|
Mean
|
Std. Deviation
|
Minimum
|
Maximum
|
|
Table 3
Trace metals in packaged groundwater samples
Co
|
Iberekodo
|
8
|
0.22a
|
0.02
|
0.20
|
0.23
|
|
(µg/L)
|
Obada
|
8
|
26.88ab
|
11.91
|
9.45
|
34.85
|
|
|
Obantoko
|
8
|
4.62ab
|
5.44
|
0.89
|
10.86
|
|
|
Asero
|
8
|
347.2b
|
231.5
|
13.87
|
548.5
|
|
|
Camp-Osiele
|
8
|
0.89a
|
0.00
|
0.89
|
0.89
|
|
|
Isolu
|
8
|
17.13ab
|
19.17
|
2.06
|
45.23
|
|
|
Makun-Sagamu
|
8
|
20.25ab
|
27.94
|
0.49
|
40.00
|
|
Cu
|
Iberekodo
|
8
|
60.51a
|
72.75
|
18.23
|
169.5
|
2000
|
(µg/L)
|
Obada
|
8
|
238.7a
|
337.9
|
46.27
|
990.2
|
|
|
Obantoko
|
8
|
76.77a
|
32.93
|
40.98
|
108.2
|
|
|
Asero
|
8
|
1341b
|
1914
|
110.8
|
4194
|
|
|
Camp-Osiele
|
8
|
83.20a
|
76.10
|
20.24
|
191
|
|
|
Isolu
|
8
|
539.7ab
|
532.9
|
0.95
|
1030
|
|
|
Makun-Sagamu
|
8
|
154.7a
|
163.5
|
1.00
|
363.4
|
300
|
Fe
|
Iberekodo
|
8
|
154.6a
|
133.2
|
8.00
|
420
|
|
(µg/L)
|
Obada
|
8
|
173.1a
|
214.2
|
18.00
|
896.8
|
|
|
Obantoko
|
8
|
491.8a
|
559.1
|
19.00
|
1741
|
|
|
Asero
|
8
|
178.9a
|
162.1
|
16.54
|
555
|
|
|
Camp-Osiele
|
8
|
242.5a
|
317.5
|
23.00
|
901.2
|
|
|
Isolu
|
8
|
172.6a
|
116.9
|
58.00
|
359
|
|
|
Makun-Sagamu
|
8
|
561.4a
|
1090
|
12.00
|
3926
|
|
Mn
|
Iberekodo
|
8
|
7.62a
|
8.59
|
1.00
|
23.25
|
400
|
(µg/L)
|
Obada
|
8
|
1118ab
|
1719
|
26.50
|
4057
|
|
|
Obantoko
|
8
|
340.3ab
|
312.2
|
16.00
|
825.3
|
|
|
Asero
|
8
|
1380ab
|
2675
|
3.00
|
8272
|
|
|
Camp-Osiele
|
8
|
46.45a
|
74.63
|
2.00
|
196.6
|
|
|
Isolu
|
8
|
2393b
|
2455
|
9.00
|
4954
|
|
|
Makun-Sagamu
|
8
|
1727ab
|
2218
|
4.00
|
4949
|
|
Mo
|
Iberekodo
|
8
|
1.37a
|
2.04
|
< 0.1
|
4.00
|
|
(µg/L)
|
Obada
|
8
|
28.00a
|
0.00
|
28.00
|
28.00
|
|
|
Obantoko
|
8
|
13.00ab
|
12.73
|
4.00
|
22.00
|
|
|
Asero
|
8
|
< 0.1a
|
0.00
|
< 0.1
|
< 0.1
|
|
|
Camp-Osiele
|
8
|
< 0.1a
|
0.00
|
< 0.1
|
< 0.1
|
|
|
Isolu
|
8
|
21.00b
|
0.00
|
21.00
|
21.00
|
|
|
Makun-Sagamu
|
8
|
20.00b
|
0.00
|
20.00
|
20.00
|
|
Ni
|
Iberekodo
|
8
|
< 0.1a
|
|
< 0.1
|
< 0.1
|
70
|
(µg/L)
|
Obada
|
8
|
21.56b
|
1.01
|
20.14
|
22.86
|
|
|
Obantoko
|
8
|
14.47b
|
8.09
|
3.31
|
22.65
|
|
|
Asero
|
8
|
< 0.1a
|
|
< 0.1
|
< 0.1
|
|
|
Camp-Osiele
|
8
|
13.18b
|
0.00
|
13.18
|
13.18
|
|
|
Isolu
|
8
|
5.97ab
|
0.00
|
5.97
|
5.97
|
|
|
Makun-Sagamu
|
8
|
25.17b
|
2.86
|
23.30
|
29.40
|
|
Zn
|
Iberekodo
|
8
|
549b
|
653.5
|
5.56
|
1737
|
3000
|
(µg/L)
|
Obada
|
8
|
191.7ab
|
300.3
|
0.31
|
863.8
|
|
|
Obantoko
|
8
|
428.1ab
|
435.4
|
33.04
|
1073
|
|
|
Asero
|
8
|
298.7ab
|
222.9
|
147
|
779.7
|
|
|
Camp-Osiele
|
8
|
83.77a
|
72.28
|
5.39
|
224.00
|
|
|
Isolu
|
8
|
234.2ab
|
367.6
|
7.64
|
850
|
|
|
Makun-Sagamu
|
8
|
429.7ab
|
281.4
|
53.00
|
734.4
|
|
SD-Standard, deviation, Dissimilar alphabets along same column are statistically different at p < 0.05, according to Duncan Multiple Range Test |
A high level of Fe in water is more associated with aesthetic quality (e.g., taste, smell, and colour) rather than health-based issues (WHO, 2017). A previous study by Emenike et al. (2017) reported similar high concentrations of Fe greater than the permissible standard of the WHO in packaged/sachet water collected in Ado Odo Ota, Ogun State, Nigeria.
The highest Mn value was observed in Isolu sachet water samples. Approximately, 57% of the sampling sites had Mn contents greater than the permissible limit of 400 µg/L (WHO, 2011). In groundwater, Mn concentration up to 1300 µg/L is attainable due to reducing reaction in natural conditions, while the level could reach 9600 µg/L in an acidic medium (WHO, 2011). High levels of Mn in water can cause brain damage in infants and young adults (HealthLink BC, 2019).
Obada water samples had the highest concentrations of Mo. Since there is no priority limit for Mo in drinking water; hence the levels that could initiate health implication may not be ascertained. However, WHO (1996) documented that the level of Mo in drinking water rarely exceeds 10 µg/L. This concentration was exceeded in samples from Obada, Obantoko, Isolu, Makun-Sagamu. Ni and Zn values of all the water samples were within the admissible limits of the WHO (WHO, 2011).
3.4 Water quality index (WQI) of packaged groundwater
Figure 2 shows the overall water quality index (WQI) data of packaged groundwater from different sampling locations in the study area. The individual WQI of samples (Table S1 in the supplementary information) was generally less than the acceptable limit of 100, indicating good quality. However, the WQIs of sachet water from Iberekodo, Obada, Obantoko and Camp-Osiele were less than 50, thereby indicating excellent quality. The highest WQI of 76 was documented in Isolu samples, of which Mn contributed the highest level of 69%. In other sampling sites such Obada, Makun-Sagamu and Asero, Mn constituted 60, 59 and 53% of the total WQI, respectively. Although, the WQIs at these sampling sites indicated good quality with values less than 100, however, it should be noted the dominance of Mn in the sachet water could pose health threats to consumers.
3.5 Health risk assessment of metals in packaged groundwater
The estimated daily intake (EDI) values of metals in packaged groundwater are presented in Table S2 (in the supplementary material). Mn was the most dosed metal in sachet water by adults and children. At four sites, the EDIs of Mn were higher than the adequate intake values of 1200 µg/day (equivalent to 80 µg/kg body weight) for children and 1800–2300 µg/day (equivalent to 30–38 µg/kg body weight) for adults (ATSDR, 2008).
Table 4 presents the hazard quotient (HQ) and hazard index (HI) values of metals in the packaged groundwater. Ca indicated the highest level of HQ in packaged groundwater consumed by adults and children with values greater than the acceptable limit of 1.0, thereby establishing non-carcinogenic adverse health effects. All the monitoring sites revealed HQ greater than 1.0 for Ca in water samples consumed by both adults and children. Mn also exhibited HQ > 1.0 in water samples consumed by children at all the monitoring sites; however, for adults, only one site has HQ < 1.0. This also established the adverse health effects of Mn through the consumption of the packaged groundwater samples. Mn is an essential trace metal required for providing assistance to many enzymes for their catalytic and regulatory functions. It is also needed for healthy cartilage, and bone; and also plays a key role in wound healing (ATSDR, 2008).
High contents of Mn may result in a neurological disorder known as ‘manganism’; a condition characterized by body weakness, lethargy, slow and clumsy gaits, speech disturbances, a masklike face, tremors, and psychological disturbances (WHO, 2011).
An adverse health effect was also estimated for Mo with HQs greater than 1.0 in water samples taken by adults (at 3 sites) and children (at 4 sites). Mo is a mineral the body requires to process proteins and genetic material such as DNA, and the metabolism of xenobiotics in the body (NIH, 2021). Specifically, Mo is involved in the activation of enzymes that assist in breaking down deleterious sulfites and prevent toxins from building up in the body (Health line, 2022). Furthermore, the reaction of Mo with sulphur can assist in reducing the amounts of copper in the body - a possible future treatment for some chronic diseases (Health line, 2022). Toxicity due to Mo rarely occurs in humans; however, high concentrations have been linked to kidney failure, diarrhea, reduced growth, and infertility in animals (Health line, 2022).
Table 4
HQ and HI of metals in the packaged groundwater samples
|
|
Adults
|
Children
|
Metal
(RfDs, µg/kg/day)
|
|
Mean
|
SD
|
Min.
|
Max.
|
Mean
|
SD
|
Min.
|
Max.
|
Ca
|
Iberekodo
|
412
|
120
|
277
|
569
|
823
|
240
|
553
|
1139
|
(0.001*)
|
Obada
|
303
|
453
|
2
|
1126
|
605
|
905
|
4
|
2252
|
|
Obantoko
|
2766
|
1194
|
1226
|
4106
|
5533
|
2387
|
2451
|
8212
|
|
Asero
|
1161
|
213
|
877
|
1354
|
2321
|
426
|
1754
|
2708
|
|
Camp-Osiele
|
771
|
756
|
260
|
1891
|
1542
|
1511
|
520
|
3782
|
|
Isolu
|
838
|
615
|
269
|
1689
|
1676
|
1229
|
539
|
3378
|
|
Makun-Sagamu
|
2007
|
863
|
755
|
2681
|
4014
|
1726
|
1509
|
5361
|
Co
|
Iberekodo
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
(60)
|
Obada
|
0.01
|
0.01
|
0.01
|
0.02
|
0.03
|
0.01
|
0.01
|
0.04
|
|
Obantoko
|
0.002
|
0.003
|
0.000
|
0.01
|
0.005
|
0.01
|
0.001
|
0.01
|
|
Asero
|
0.18
|
0.12
|
0.01
|
0.29
|
0.37
|
0.25
|
0.01
|
0.58
|
|
Camp-Osiele
|
0.000
|
0.000
|
0.000
|
0.000
|
0.001
|
0.000
|
0.001
|
0.001
|
|
Isolu
|
0.01
|
0.01
|
0.001
|
0.02
|
0.02
|
0.02
|
0.002
|
0.05
|
|
Makun-Sagamu
|
0.01
|
0.01
|
0.000
|
0.02
|
0.02
|
0.03
|
0.001
|
0.04
|
|
Mkun-Shgmu
|
0.19
|
0.11
|
0.08
|
0.29
|
0.38
|
0.22
|
0.16
|
0.58
|
Cu
|
Iberekodo
|
0.10
|
0.12
|
0.03
|
0.27
|
0.19
|
0.23
|
0.06
|
0.54
|
(20)
|
Obada
|
0.38
|
0.54
|
0.07
|
1.58
|
0.76
|
1.08
|
0.15
|
3.17
|
|
Obantoko
|
0.12
|
0.05
|
0.07
|
0.17
|
0.25
|
0.11
|
0.13
|
0.35
|
|
Asero
|
2.14
|
3.06
|
0.18
|
6.70
|
4.29
|
6.12
|
0.35
|
13.41
|
|
Camp-Osiele
|
0.13
|
0.12
|
0.03
|
0.31
|
0.27
|
0.24
|
0.06
|
0.61
|
|
Isolu
|
0.86
|
0.85
|
0.002
|
1.65
|
1.73
|
1.70
|
0.003
|
3.29
|
|
Makun-Sagamu
|
0.25
|
0.26
|
0.002
|
0.58
|
0.49
|
0.52
|
0.003
|
1.16
|
Fe
|
Iberekodo
|
0.01
|
0.01
|
0.000
|
0.02
|
0.01
|
0.01
|
0.001
|
0.04
|
(700)
|
Obada
|
0.01
|
0.01
|
0.001
|
0.04
|
0.02
|
0.02
|
0.002
|
0.08
|
|
Obantoko
|
0.02
|
0.03
|
0.001
|
0.08
|
0.04
|
0.05
|
0.002
|
0.16
|
|
Asero
|
0.01
|
0.01
|
0.001
|
0.03
|
0.02
|
0.01
|
0.002
|
0.05
|
|
Camp-Osiele
|
0.01
|
0.01
|
0.001
|
0.04
|
0.02
|
0.03
|
0.002
|
0.08
|
|
Isolu
|
0.01
|
0.01
|
0.003
|
0.02
|
0.02
|
0.01
|
0.01
|
0.03
|
|
Makun-Sagamu
|
0.03
|
0.05
|
0.001
|
0.18
|
0.05
|
0.10
|
0.001
|
0.36
|
Mg
|
Iberekodo
|
0.01
|
0.00
|
0.003
|
0.01
|
0.02
|
0.01
|
0.01
|
0.02
|
(1.1*)
|
Obada
|
0.09
|
0.11
|
0.000
|
0.30
|
0.18
|
0.21
|
0.001
|
0.59
|
|
Obantoko
|
0.14
|
0.11
|
0.05
|
0.29
|
0.29
|
0.23
|
0.09
|
0.59
|
|
Asero
|
0.12
|
0.08
|
0.03
|
0.21
|
0.25
|
0.16
|
0.05
|
0.43
|
|
Camp-Osiele
|
0.01
|
0.00
|
0.00
|
0.01
|
0.01
|
0.01
|
0.01
|
0.02
|
|
Isolu
|
0.36
|
0.29
|
0.09
|
0.65
|
0.72
|
0.58
|
0.18
|
1.30
|
|
Makun-Sagamu
|
0.22
|
0.18
|
0.08
|
0.46
|
0.43
|
0.35
|
0.16
|
0.93
|
Mn
|
Iberekodo
|
0.49
|
0.55
|
0.06
|
1.49
|
0.97
|
1.10
|
0.13
|
2.97
|
(0.5)
|
Obada
|
71.48
|
109.90
|
1.69
|
259.38
|
142.95
|
219.80
|
3.39
|
518.76
|
|
Obantoko
|
21.76
|
19.96
|
1.02
|
52.76
|
43.51
|
39.92
|
2.05
|
105.53
|
|
Asero
|
88.23
|
171.02
|
0.19
|
528.86
|
176.46
|
342.04
|
0.38
|
1057.71
|
|
Camp-Osiele
|
2.97
|
4.77
|
0.13
|
12.57
|
5.94
|
9.54
|
0.26
|
25.14
|
|
Isolu
|
152.99
|
156.96
|
0.58
|
316.73
|
305.98
|
313.91
|
1.15
|
633.45
|
|
Makun-Sagamu
|
110.41
|
141.80
|
0.26
|
316.41
|
220.83
|
283.61
|
0.51
|
632.81
|
Mo
|
Iberekodo
|
0.09
|
0.13
|
0.003
|
0.26
|
0.18
|
0.26
|
0.01
|
0.51
|
(0.5)
|
Obada
|
1.79
|
0.00
|
1.79
|
1.79
|
3.58
|
0.00
|
3.58
|
3.58
|
|
Obantoko
|
0.83
|
0.81
|
0.26
|
1.41
|
1.66
|
1.63
|
0.51
|
2.81
|
|
Asero
|
0.00
|
0.000
|
0.003
|
0.003
|
0.01
|
0.000
|
0.01
|
0.01
|
|
Camp-Osiele
|
0.00
|
0.000
|
0.003
|
0.003
|
0.01
|
0.000
|
0.01
|
0.01
|
|
Isolu
|
1.34
|
0.000
|
1.34
|
1.34
|
2.69
|
0.000
|
2.69
|
2.69
|
|
Makun-Sagamu
|
1.28
|
0.000
|
1.28
|
1.28
|
2.56
|
0.000
|
2.56
|
2.56
|
Na
|
Iberekodo
|
0.07
|
0.03
|
0.03
|
0.11
|
0.14
|
0.06
|
0.07
|
0.21
|
(3.4*)
|
Obada
|
0.34
|
0.28
|
0.05
|
0.60
|
0.68
|
0.55
|
0.10
|
1.20
|
|
Obantoko
|
0.15
|
0.10
|
0.06
|
0.29
|
0.30
|
0.21
|
0.12
|
0.59
|
|
Asero
|
0.33
|
0.40
|
0.04
|
0.92
|
0.66
|
0.80
|
0.09
|
1.84
|
|
Camp-Osiele
|
0.05
|
0.02
|
0.02
|
0.08
|
0.11
|
0.05
|
0.05
|
0.15
|
|
Isolu
|
0.15
|
0.02
|
0.13
|
0.16
|
0.29
|
0.03
|
0.26
|
0.33
|
|
Makun-Sagamu
|
0.09
|
0.02
|
0.06
|
0.10
|
0.17
|
0.04
|
0.12
|
0.20
|
Ni
|
Iberekodo
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
(20)
|
Obada
|
0.03
|
0.00
|
0.03
|
0.04
|
0.07
|
0.00
|
0.06
|
0.07
|
|
Obantoko
|
0.02
|
0.01
|
0.01
|
0.04
|
0.05
|
0.03
|
0.01
|
0.07
|
|
Asero
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
|
Camp-Osiele
|
0.02
|
0.000
|
0.02
|
0.02
|
0.04
|
0.000
|
0.04
|
0.04
|
|
Isolu
|
0.01
|
0.000
|
0.01
|
0.01
|
0.02
|
0.000
|
0.02
|
0.02
|
|
Makun-Sagamu
|
0.04
|
0.005
|
0.04
|
0.05
|
0.08
|
0.01
|
0.07
|
0.09
|
Zn
|
Iberekodo
|
0.06
|
0.07
|
0.001
|
0.19
|
0.12
|
0.14
|
0.001
|
0.37
|
(300)
|
Obada
|
0.02
|
0.03
|
0.000
|
0.09
|
0.04
|
0.06
|
0.000
|
0.18
|
|
Obantoko
|
0.05
|
0.05
|
0.004
|
0.11
|
0.09
|
0.09
|
0.01
|
0.23
|
|
Asero
|
0.03
|
0.02
|
0.02
|
0.08
|
0.06
|
0.05
|
0.03
|
0.17
|
|
Camp-Osiele
|
0.01
|
0.01
|
0.001
|
0.02
|
0.02
|
0.02
|
0.001
|
0.05
|
|
Isolu
|
0.02
|
0.04
|
0.001
|
0.09
|
0.05
|
0.08
|
0.002
|
0.18
|
|
Makun-Sagamu
|
0.05
|
0.03
|
0.01
|
0.08
|
0.09
|
0.06
|
0.011
|
0.16
|
HI
|
Iberekodo
|
413
|
|
|
|
825
|
|
|
|
|
Obada
|
377
|
|
|
|
753
|
|
|
|
|
Obantoko
|
2789
|
|
|
|
5579
|
|
|
|
|
Asero
|
1252
|
|
|
|
2503
|
|
|
|
|
Camp-Osiele
|
774
|
|
|
|
1548
|
|
|
|
|
Isolu
|
994
|
|
|
|
1988
|
|
|
|
|
Makun-Sagamu
|
2119
|
|
|
|
4239
|
|
|
|
*mg/kg/day, SD-Standard deviation, Min.- Minimum, Max.–Maximum, RfD – Reference dose |
Ca is an essential major element required for the growth and strength of bones, maintenance of proper hormone level, and optimal function of nerves (Cleveland Clinic, 2022). However, a high level of Ca can cause a condition known as hypercalcemia, which is characterized by headache, fatigue, kidney stone, excessive urination and thirst, nausea, and abdominal pain (Marcin, 2018). Hypercalcemia may result from high Ca absorption due to lung diseases, cancer of the lung, and hyperthyroidism (Cleveland Clinic, 2022).
High HQs greater than the acceptable limit of 1.0 were documented for Cu in the packaged groundwater consumed by adults (at one site) and children (at three sites). Correspondingly, the past work of Emenike et al. (2017) reported the HQs > 1.0 for Cu in selected brands of sachet water from Ado Odo Ota, Ogun State, Nigeria. The hazard index (HI) values of metals in sachet water were generally greater than the acceptable limit of 1.0, indicating unsafe consumption. The HI distribution in sachet water at the sampling locations followed the descending order of Obantoko > Makun-Sagamu > Asero > Isolu > Camp > Iberekodo > Obada. Children were two times more at adverse health risk than adults.
Figure S1 (in the supplementary information) shows the contributions of metals to non-carcinogenic adverse effects in sachet water. Ca was the highest contributor to the adverse health effects showing fractions ranging between 80% (Obada) and 100% (Iberekodo). Mn was second the largest contributor to the non-carcinogenic effects with values varying from 5%(Makun-Sagamu) to 19% (Obada).
The cancer risk (CR) data of Co and Ni in the packaged/sachet groundwater are shown in Table 5. The CR values of Co were higher than the acceptable limit of 1.0 x 10− 4 (USEPA, 2007) at all the sampling sites, except in Iberekodo. Furthermore, the CRs of Ni at Obada, Obantoko, Camp-Osiele, and Makun-Sagamu were also higher than the permissible limit, establishing the probable development of cancer. The research of the International Agency for Research on Cancer (IARC) based on animal data suggested possible human carcinogenicity of Co (ATSDR, 2004). The carcinogenic effects of Co and Ni in different drinks from Abeokuta were established in the past study of Taiwo et al. (2020). The contributions of Co and Ni to the sum of cancer risk are shown in Figure S2 (in the supplementary information). Co formed the largest portion (42–100%) of the total cancer burden, corresponding to the recent study of Taiwo et al. (2020) in different drink samples. However, at Camp-Osiele, Ni was the largest contributor (58%) to the total cancer risk. In 2015, cancer was reported to have been responsible for 8.8 million global deaths; out of which 70% occurred in low and middle income countries (WHO, 2021).
Table 5
Cancer risk values of Co and Ni in the packaged groundwater
|
|
|
Adults
|
|
|
|
Children
|
|
|
Metals
(CSF, 1/mg/kg/day)
|
|
Mean
|
SD
|
Min.
|
Max.
|
Mean
|
SD
|
Min.
|
Max.
|
Co
|
Iberekodo
|
3.8x10− 5
|
3.4x10− 6
|
3.4x10− 5
|
4.0x10− 5
|
2.8 x10− 4
|
2.5x10− 5
|
2.5x10− 4
|
2.9x10− 4
|
(9.8)
|
Obada
|
4.6 x10− 3
|
2.1x10− 3
|
1.6x10− 3
|
6.0x10− 3
|
3.4 x10− 2
|
1.5x10− 2
|
1.2x10− 2
|
4.4x10− 2
|
|
Obantoko
|
8.0x10− 4
|
9.4x10− 4
|
1.5x10− 4
|
1.9x10− 3
|
5.8 x10− 3
|
6.8x10− 3
|
1.1x10− 3
|
1.4x10− 2
|
|
Asero
|
6.0x10− 2
|
4.0x10− 2
|
2.4x10− 3
|
9.5x10− 2
|
4.4 x10− 1
|
2.9x10− 1
|
1.7x10− 2
|
6.9x10− 1
|
|
Camp-Osiele
|
1.5x10− 4
|
0.0
|
1.5x10− 4
|
1.5x10− 4
|
1.1 x10− 3
|
0.0
|
1.1x10− 3
|
1.1x10− 3
|
|
Isolu
|
3.0x10− 3
|
3.3x10− 3
|
3.6x10− 4
|
7.8x10− 3
|
2.1 x10− 2
|
2.4x10− 2
|
2.6x10− 3
|
5.7x10− 2
|
|
Makun-Sagamu
|
3.5x10− 3
|
4.8x10− 3
|
8.4x10− 5
|
6.9x10− 3
|
2.5 x10− 2
|
3.5x10− 2
|
6.1x10− 4
|
5.0x10− 2
|
Ni
|
Iberekodo
|
8.0x10− 7
|
0.0
|
8.0x10− 7
|
8.0x10− 7
|
5.8 x10− 6
|
0.0
|
5.8x10− 6
|
5.8x10− 6
|
(0.91)
|
Obada
|
3.5x10− 4
|
1.6x10− 5
|
3.2x10− 4
|
3.7x10− 4
|
2.5 x10− 3
|
1.2x10− 4
|
2.3x10− 3
|
2.7x10− 3
|
|
Obantoko
|
2.3x10− 4
|
1.3x10− 4
|
5.3x10− 5
|
3.6x10− 4
|
1.7 x10− 3
|
9.4x10− 4
|
3.9x10− 4
|
2.6x10− 3
|
|
Asero
|
8.0x10− 7
|
0.0
|
8.0x10− 7
|
8.0x10− 7
|
5.8 x10− 6
|
0.0
|
5.8x10− 6
|
5.8x10− 6
|
|
Camp-Osiele
|
2.1x10− 4
|
0.0
|
2.1x10− 4
|
2.1x10− 4
|
1.5 x10− 3
|
0.0
|
1.5x 10− 3
|
1.5x10− 3
|
|
Isolu
|
9.6x10− 5
|
0.0
|
9.6x10− 5
|
9.6x10− 5
|
6.9 x10− 4
|
0.0
|
6.9x10− 4
|
6.9x10− 4
|
|
Makun-Sagamu
|
4.0x10− 4
|
4.6x10− 5
|
3.7x10− 4
|
4.7x10− 4
|
2.9x10− 3
|
3.3x10− 4
|
2.7x10− 3
|
3.4x10− 3
|
|
Iberekodo
|
3.9x10− 5
|
|
|
|
2.9x10− 4
|
|
|
|
|
Obada
|
5.0x10− 3
|
|
|
|
3.7x10− 2
|
|
|
|
|
Obantoko
|
1.0x10− 3
|
|
|
|
7.5x10− 3
|
|
|
|
|
Asero
|
6.0x10− 2
|
|
|
|
4.4x10− 1
|
|
|
|
|
Camp-Osiele
|
3.6x10− 4
|
|
|
|
2.6x10− 3
|
|
|
|
|
Isolu
|
3.1x10− 3
|
|
|
|
2.2x10− 2
|
|
|
|
|
Makun-Sagamu
|
3.9x10− 3
|
|
|
|
2.8x10− 2
|
|
|
|
SD-Standard deviation, Min. - Minimum, Max. – Maximum, RfD – Reference dose |
3.5 Regression model of WQI vs. health risk indices
Table 6 presents the regression model of the WQI against the hazard index and cancer risk. The model indicated quantified weak relationship between the water quality index and health risk indices. Even though, Mn appeared to contribute mostly to both the WQI and HI, however the regression model revealed very weak non-significant association, probably due to other parameters involved in their computation. For CR, none of the carcinogenic metals was included in the WQI estimation, and thus are weakly related. Despite being weak, the positive correlation that existed in this model indicated probable influence of the WQI of the packaged/sachet groundwater on the health risk of the consumers, especially from non-carcinogenic health issues. The regression model of the WQI versus health risk indices suggests safe consumption of the packaged/sachet groundwater in the study area.
Table 6
Regression of water quality index and human health risk of packaged/sachet water samples
|
Regression model
|
R
|
R2
|
Significance
|
WQI
|
33.94 + 0.01 HI + 307.56 CR
|
0.387
|
0.149
|
0.723
|
WQI – water quality index; HI- hazard index; CR – cancer risk |