Table 1. Classifications for geochemical indices; CD, PLI, Igeo, EF, ER and PERI.
CD
|
Classification
|
|
PLI
|
Classification
|
|
Igeo
|
classification
|
|
EF
|
Classification
|
|
ERI
|
Classification
|
|
PERI
|
Classification
|
8
|
Moderate contamination
|
|
4
|
Moderately polluted
|
|
Igeo < 0
|
Unpolluted
|
|
EF < 0
|
Deficiency to minimal enrichment
|
|
ER < 40
|
Low risk
|
|
PERI < 50
|
Low risk
|
16
|
High contamination
|
|
6
|
Significantly polluted
|
|
0 ≤ Igeo < 1
|
Unpolluted to moderately polluted
|
|
2 ≤ EF < 5
|
Moderate enrichment
|
|
40 ≤ ER < 80
|
Moderate risk
|
|
50 ≤ PERI < 200
|
Moderate risk
|
32
|
Very high contamination
|
|
8
|
Strongly polluted
|
|
1 ≤ Igeo < 2
|
Moderately polluted
|
|
5 ≤ EF < 20
|
Significant enrichment
|
|
80 ≤ ER < 160
|
Considerable risk
|
|
200 ≤ PERI < 300
|
Considerable risk
|
|
|
|
10
|
Extremely polluted
|
|
2 ≤ Igeo < 3
|
Moderately to heavily polluted
|
|
20 ≤ EF < 40
|
Very high enrichment
|
|
160 ≤ ER < 320
|
High risk
|
|
PERI > 300
|
High risk
|
|
|
|
|
|
|
3 ≤ Igeo ≤ 4
|
Heavily polluted
|
|
EF > 40
|
Extremely high enrichment
|
|
ER > 320
|
Very high risk
|
|
|
|
|
|
|
|
|
|
4 ≤ Igeo < 5
|
Heavily to extremely polluted
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Igeo > 6
|
Extremely polluted
|
|
|
|
|
|
|
|
|
|
Table 2. Statistical summary of major soil physico–chemical parameters
Parameters
|
Farm soils (n=20)
|
|
River sediments (n=9)
|
Min
|
Max
|
Mean
|
Median
|
Std
|
|
Min
|
Max
|
Mean
|
Median
|
Std
|
pH
|
6.46
|
7.88
|
6.85
|
6.83
|
0.28
|
|
6.99
|
7.98
|
7.47
|
7.44
|
0.33
|
EC (µS cm–1)
|
280.00
|
857.50
|
518.00
|
506.75
|
152.07
|
|
107.85
|
574.00
|
238.63
|
234.50
|
140.52
|
WHC (mL L–1)
|
6.40
|
18.98
|
10.60
|
2.93
|
10.52
|
|
6.00
|
8.32
|
6.95
|
0.88
|
6.48
|
TOM (%)
|
1.19
|
10.37
|
5.23
|
5.08
|
2.39
|
|
0.80
|
1.98
|
1.43
|
1.49
|
0.46
|
TOC (%)
|
0.69
|
6.01
|
3.03
|
2.95
|
1.38
|
|
0.46
|
1.15
|
0.83
|
0.87
|
0.26
|
PD (g cm–3)
|
1.77
|
3.70
|
2.42
|
2.32
|
0.47
|
|
2.57
|
2.97
|
2.74
|
2.70
|
0.17
|
Na (mg kg–1)
|
504
|
1,176
|
843
|
840
|
165
|
|
721
|
1,635
|
1,174
|
1,119
|
276
|
Mg (mg kg–1)
|
5,035
|
11,235
|
8,118
|
8,189
|
1,839
|
|
1,267
|
9,168
|
5,971
|
6,332
|
2,338
|
K (mg kg–1)
|
1,350
|
2,184
|
1,603
|
1,542
|
225
|
|
972
|
1,959
|
1,383
|
1,295
|
339
|
Ca (mg kg–1)
|
8,062
|
30,643
|
11,009
|
10,031
|
4,726
|
|
5,989
|
11,456
|
9,072
|
9,541
|
1,946
|
EC– Electrical conductivity; PD– particle density; TOC– Total organic carbon; TOM– Total organic matter; WHC– water holding capacity;
Table 3. Statistical summary of heavy metal concentrations in farm soils and river sediments from Vatukoula.
Metal
|
Min
|
Max
|
Mean
|
Median
|
Std
|
SEM
|
Kurtosis
|
Skewness
|
CI (95%)
|
LB
|
UB
|
Farm Soils (mg kg–1, n=20)
|
Pb
|
25.95
|
63.64
|
45.41
|
47.02
|
11.19
|
2.50
|
–0.95
|
–0.33
|
40.17
|
50.65
|
Zn
|
64.02
|
116.85
|
80.03
|
78.40
|
11.44
|
2.56
|
4.91
|
1.67
|
74.68
|
85.38
|
Cd
|
1.29
|
1.97
|
1.74
|
1.77
|
0.18
|
0.04
|
1.96
|
–1.38
|
1.66
|
1.83
|
Ni
|
47.18
|
63.49
|
57.15
|
57.77
|
4.69
|
1.05
|
–0.43
|
–0.68
|
54.95
|
59.35
|
Cu
|
91.08
|
131.24
|
110.37
|
109.29
|
13.12
|
2.93
|
–1.39
|
0.09
|
104.23
|
116.51
|
Cr
|
100.37
|
180.90
|
136.21
|
137.03
|
22.78
|
5.09
|
–0.80
|
0.06
|
125.55
|
146.87
|
Mn
|
442.05
|
544.94
|
503.83
|
508.19
|
24.70
|
5.52
|
1.19
|
–0.95
|
492.27
|
515.39
|
Co
|
29.90
|
38.41
|
35.36
|
36.43
|
2.62
|
0.59
|
–0.62
|
–0.71
|
34.14
|
36.59
|
Fe (%)
|
4.27
|
5.85
|
5.11
|
5.06
|
0.46
|
0.10
|
–0.74
|
0.04
|
4.89
|
5.32
|
|
River Sediments (mg kg–1, n=9)
|
Pb
|
59.25
|
77.57
|
69.31
|
68.59
|
6.65
|
2.22
|
–1.54
|
–0.09
|
64.20
|
74.43
|
Zn
|
53.85
|
80.68
|
69.82
|
73.57
|
9.53
|
3.18
|
–0.97
|
–0.74
|
62.49
|
77.14
|
Cd
|
1.57
|
2.09
|
1.82
|
1.82
|
0.15
|
0.05
|
0.59
|
0.26
|
1.70
|
1.93
|
Ni
|
40.37
|
62.62
|
49.67
|
49.51
|
6.78
|
2.26
|
0.84
|
0.43
|
44.46
|
54.88
|
Cu
|
59.08
|
123.15
|
88.95
|
87.62
|
20.36
|
6.79
|
–0.70
|
0.19
|
73.30
|
104.61
|
Cr
|
91.20
|
205.87
|
143.12
|
135.97
|
34.34
|
11.45
|
0.17
|
0.45
|
116.72
|
169.52
|
Mn
|
416.02
|
643.49
|
506.75
|
501.35
|
73.26
|
24.42
|
–0.11
|
0.74
|
450.43
|
563.06
|
Co
|
24.49
|
42.73
|
32.71
|
32.76
|
5.68
|
1.89
|
0.13
|
0.09
|
28.34
|
37.08
|
Fe (%)
|
3.84
|
5.58
|
4.72
|
4.77
|
0.63
|
0.21
|
–1.13
|
0.07
|
4.24
|
5.21
|
All metal data are expressed in mg kg–1 except Fe, which is expressed in %.
CI– Confidence interval
Std– Standard deviation
SEM– Standard error of the mean
Table 4. Metal concentrations from Vatukoula compared with established soil and sediment quality guidelines
Metals
|
Soil values (mg kg–1)
|
|
Sediment values (mg kg–1)
|
This study
|
WHO MPCa
|
CASQCb
|
Dutch Target Valuec
|
Background concentrationd
|
This study
|
CFSQCb
|
ANZEC DGVe
|
Background concentrationf
|
Pb
|
45.41
|
100
|
70
|
85
|
27
|
|
69.31
|
35
|
50
|
7.3
|
Zn
|
80.03
|
200
|
250
|
140
|
70
|
|
69.82
|
123
|
200
|
29.5
|
Cd
|
1.74
|
3
|
1.4
|
0.8
|
0.41
|
|
1.82
|
0.6
|
1.5
|
0.96
|
Ni
|
57.15
|
75
|
45
|
35
|
29
|
|
49.67
|
–
|
21
|
8.7
|
Cu
|
110.37
|
100
|
63
|
36
|
38.9
|
|
88.95
|
35.7
|
65
|
29.6
|
Cr
|
136.21
|
100
|
64
|
100
|
59
|
|
143.12
|
37.3
|
80
|
20
|
Mn
|
503.83
|
1500
|
–
|
–
|
488
|
|
506.75
|
–
|
1500
|
207.2
|
Co
|
35.36
|
30
|
40
|
–
|
30
|
|
32.71
|
–
|
50
|
8.64
|
Fe (%)
|
5.11
|
–
|
–
|
–
|
2.7
|
|
4.72
|
–
|
–
|
–
|
aWHO Maximum Permissible Concentration.
bCanadian Environmental Quality Guidelines (CEQG).
cDutch Soil Quality Criteria (Denneman and Robberse, 1990).
dGlobal background soil heavy metal concentrations (Kabata–Pendias, 2010).
eAustralian and New Zealand sediment default guideline values.
fsediment heavy metal concentrations reported for the Great Astrolabe reef, Fiji (Morrison et al., 1997).
Table 5. Metal concentrations in soils and sediments compared with values from other parts of Fiji and mining areas around the world.
Location
|
Soil metal concentrations (mg kg–1)
|
Reference
|
Pb
|
Zn
|
Cd
|
Ni
|
Cu
|
Cr
|
Mn
|
Co
|
Fe (%)
|
Vatukoula, Fiji
|
25.95–63.94
|
64.02–116.85
|
1.29–1.97
|
47.18–63.49
|
91.08–131.24
|
100.37–180.90
|
442.05–544.94
|
29.90–38.41
|
4.27–5.85
|
This study
|
Suva, Fiji
|
59.3
|
507
|
3.1
|
32.4
|
265.7
|
34.0
|
–
|
33.2
|
3.95
|
(Maeaba et al., 2019)
|
Torul, Turkey
|
27.38–33.16
|
42.04–55.50
|
1.23–1.45
|
41.50–72.00
|
31.71–41.84
|
47.80–65.25
|
–
|
–
|
–
|
(Sungur et al., 2020)
|
Central Spis, Slovakia
|
30.1–503.5
|
148.9–1697.8
|
1.12–7.4
|
17.9–342.3
|
17.3–1273.7
|
22.2–331.9
|
–
|
8.55–30.2
|
–
|
(Demková et al., 2017)
|
Co Dinh Mine, Vietnam
|
Nd–1.08
|
–
|
–
|
0.06–32.3
|
0.01–0.58
|
0.06–13.2
|
–
|
Nd–3.06
|
–
|
(Kien et al., 2010)
|
Iludun–Oro, Nigeria
|
0–687
|
7–222
|
–
|
1.6–93.1
|
8.8–145
|
1.4–81
|
0.01–0.11
|
–
|
1.64–8.87
|
(Oyebamiji et al., 2018)
|
|
Sediment metal concentrations (mg kg–1)
|
|
Nasivi River, Fiji
|
59.25–77.57
|
53.08–80.68
|
1.57–2.09
|
40.37–62.62
|
59.08–123.15
|
91.20–205.87
|
416.02–643.49
|
24.49–42.73
|
3.48–5.58
|
This study
|
Suva Harbor, Fiji
|
22–93.5
|
40.2–269
|
–
|
–
|
21.4–143.0
|
–
|
–
|
–
|
1.40–4.87
|
(Maata and Singh, 2008)
|
Raohe Basin, China
|
39.63
|
32.31
|
0.51
|
31.03
|
197.21
|
35.26
|
–
|
–
|
–
|
(Wei et al., 2019)
|
Molonglo River, Australia
|
23–1796
|
697–6818
|
0.13–8.7
|
–
|
10–628
|
–
|
–
|
–
|
–
|
(Marasinghe Wadige et al., 2016)
|
Jequetepeque River Basin, Peru
|
62.6
|
241.6
|
7.4
|
10.3
|
91.7
|
5.2
|
1841
|
–
|
1.58%
|
(Yacoub et al., 2012)
|
Ipojuca River, Brazil
|
36.27
|
63.27
|
0.16
|
3.01
|
4.42
|
9.10
|
–
|
–
|
0.11%
|
(Silva et al., 2019)
|
Table 6. Chronic daily intake (CDI), hazard quotient (HQ) and cumulative hazard index (HI) for non–carcinogenic risk.
Metals
|
Adults
|
Children
|
CDIing
|
CDIinh
|
CDIderm
|
HQing
|
HQinh
|
HQderm
|
HI
|
CDIing
|
CDIinh
|
CDIderm
|
HQing
|
HQinh
|
HQderm
|
HI
|
Pb
|
7.24E–05
|
1.06E–08
|
2.89E–06
|
2.07E–02
|
3.02E–06
|
5.50E–03
|
2.62E–02
|
6.75E–04
|
2.48E–08
|
1.89E–05
|
1.93E–01
|
7.05E–06
|
3.60E–02
|
2.29E–01
|
Zn
|
1.05E–04
|
1.55E–08
|
4.20E–06
|
3.51E–04
|
5.16E–08
|
7.00E–05
|
4.21E–04
|
9.83E–04
|
3.61E–08
|
2.75E–05
|
3.28E–03
|
1.20E–07
|
4.59E–04
|
3.73E–03
|
Cd
|
2.42E–06
|
3.56E–10
|
9.65E–08
|
2.42E–03
|
3.56E–05
|
9.65E–03
|
1.21E–02
|
2.26E–05
|
8.30E–10
|
6.32E–07
|
2.26E–02
|
8.30E–05
|
6.32E–02
|
8.58E–02
|
Ni
|
7.51E–05
|
1.10E–08
|
3.00E–06
|
3.76E–03
|
5.36E–07
|
5.55E–04
|
4.31E–03
|
7.01E–04
|
2.58E–08
|
1.96E–05
|
3.51E–02
|
1.25E–06
|
3.63E–03
|
3.87E–02
|
Cu
|
1.42E–04
|
2.09E–08
|
5.67E–06
|
3.83E–03
|
5.20E–06
|
4.72E–04
|
4.31E–03
|
1.33E–03
|
4.88E–08
|
3.71E–05
|
3.57E–02
|
1.21E–05
|
3.09E–03
|
3.89E–02
|
Cr
|
1.90E–04
|
2.79E–08
|
7.56E–06
|
6.32E–02
|
9.75E–04
|
1.26E–01
|
1.90E–01
|
1.77E–03
|
6.50E–08
|
4.95E–05
|
5.90E–01
|
2.27E–03
|
8.26E–01
|
1.42E+00
|
Mn
|
6.91E–04
|
1.02E–07
|
2.76E–05
|
1.98E–01
|
2.03E–03
|
5.25E–02
|
2.52E–01
|
6.45E–03
|
2.37E–07
|
1.81E–04
|
1.84E+00
|
4.75E–03
|
3.44E–01
|
2.19E+00
|
Co
|
4.73E–05
|
6.96E–09
|
1.89E–06
|
2.37E–03
|
1.22E–03
|
3.31E–01
|
3.35E–01
|
4.42E–04
|
1.62E–08
|
1.24E–05
|
2.21E–02
|
2.85E–03
|
2.17E+00
|
2.19E+00
|
Fe
|
6.83E–02
|
1.00E–05
|
2.73E–03
|
9.76E–02
|
1.44E–05
|
3.90E–02
|
1.37E–01
|
6.38E–01
|
2.34E–05
|
1.79E–02
|
9.11E–01
|
3.35E–05
|
2.55E–01
|
1.17E+00
|
Table. 7. Carcinogenic risk for different exposure pathways for adults and children.
Metals
|
Adults
|
Children
|
CRing
|
CRinh
|
CRderm
|
ILCR
|
CRing
|
CRinh
|
CRderm
|
ILCR
|
Pb
|
6.15E–07
|
9.05E–11
|
2.45E–08
|
6.40E–07
|
5.74E–06
|
2.11E–10
|
1.61E–07
|
5.90E–06
|
Cd
|
1.52E–05
|
2.24E–09
|
6.08E–07
|
1.58E–05
|
1.42E–04
|
5.23E–09
|
3.98E–06
|
1.46E–04
|
Cr
|
9.48E–05
|
1.39E–08
|
3.78E–06
|
9.86E–05
|
8.84E–04
|
3.25E–08
|
2.48E–05
|
9.09E–04
|
Ni
|
6.83E–05
|
1.01E–08
|
2.73E–06
|
7.11E–05
|
6.38E–04
|
2.35E–08
|
1.79E–05
|
6.56E–04
|
Table 8. Pearson correlation matrix showing the relationships between soil parameters and heavy metal concentration
|
%sand
|
%silt
|
%clay
|
pH
|
EC
|
WHC %
|
SOM
|
PD
|
CEC
|
Pb
|
Zn
|
Cd
|
Ni
|
Cu
|
Cr
|
Mn
|
Co
|
Fe
|
%sand
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
%silt
|
-.97**
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
%clay
|
-.47*
|
.35
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
pH
|
.38
|
-.10
|
-.41*
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
EC
|
-.54**
|
.39*
|
.56**
|
-.635**
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
WHC %
|
-.56**
|
.57**
|
.60**
|
-.584**
|
.866**
|
1
|
|
|
|
|
|
|
|
|
|
|
|
|
SOM
|
-.62**
|
.55**
|
.67**
|
-.664**
|
.828**
|
.928**
|
1
|
|
|
|
|
|
|
|
|
|
|
|
PD
|
.35
|
-.30
|
-.62**
|
.347
|
-.467*
|
-.552**
|
-.557**
|
1
|
|
|
|
|
|
|
|
|
|
|
CEC
|
-.61**
|
.51**
|
.93**
|
-.543**
|
.737**
|
.817**
|
.893**
|
-.659**
|
1
|
|
|
|
|
|
|
|
|
|
Pb
|
.39
|
-.39*
|
-.46*
|
.690**
|
-.583**
|
-.713**
|
-.729**
|
.473*
|
-.625**
|
1
|
|
|
|
|
|
|
|
|
Zn
|
-.49*
|
.61**
|
.51**
|
-.063
|
.331
|
.522**
|
.445*
|
-.454*
|
.553**
|
-.311
|
1
|
|
|
|
|
|
|
|
Cd
|
.15
|
-.19
|
-.32
|
.235
|
-.163
|
-.295
|
-.545**
|
.259
|
-.455*
|
.385*
|
-.030
|
1
|
|
|
|
|
|
|
Ni
|
-.34
|
.39*
|
.48**
|
-.413*
|
.558**
|
.521**
|
.477*
|
-.566**
|
.534**
|
-.301
|
.640**
|
.202
|
1
|
|
|
|
|
|
Cu
|
-.39
|
.08
|
.40*
|
-.435*
|
.593**
|
.364
|
.447*
|
-.415*
|
.466*
|
-.216
|
.317
|
.128
|
.656**
|
1
|
|
|
|
|
Cr
|
.17
|
.15
|
-.05
|
.180
|
-.159
|
-.064
|
-.150
|
.061
|
-.098
|
.340
|
.220
|
.326
|
.407*
|
-.161
|
1
|
|
|
|
Mn
|
-.03
|
.07
|
.21
|
.002
|
.208
|
.174
|
.230
|
-.400*
|
.253
|
.110
|
.353
|
-.096
|
.280
|
.315
|
-.146
|
1
|
|
|
Co
|
-.32
|
.33
|
.39*
|
-.336
|
.499**
|
.497**
|
.411*
|
-.486*
|
.445*
|
-.140
|
.571**
|
.246
|
.888**
|
.591**
|
.490**
|
.301
|
1
|
|
Fe
|
-.33
|
.44*
|
.45*
|
-.436*
|
.461*
|
.637**
|
.533**
|
-.491**
|
.525**
|
-.51**
|
.500**
|
-.130
|
.616**
|
.121
|
.449*
|
.023
|
.715**
|
1
|
Table 9. Principal component analysis for selected heavy metals in farm soils and river sediments from Vatukoula, Fiji.
Components
|
Initial eigenvalues
|
|
Heavy metals
|
Component matrix
|
Total
|
Variability (%)
|
Cumulative %
|
PC1
|
PC2
|
PC3
|
PC4
|
PC5
|
PC1
|
3.713
|
41.261
|
41.261
|
|
Pb
|
–0.178
|
0.569
|
0.291
|
0.322
|
–0.206
|
PC2
|
1.804
|
20.046
|
61.307
|
|
Zn
|
0.388
|
–0.120
|
0.002
|
0.289
|
0.719
|
PC3
|
1.427
|
15.856
|
77.163
|
|
Cd
|
0.071
|
0.551
|
0.212
|
–0.426
|
0.482
|
PC4
|
0.943
|
10.477
|
87.640
|
|
Ni
|
0.492
|
0.042
|
0.065
|
–0.131
|
–0.059
|
PC5
|
0.505
|
5.610
|
93.250
|
|
Cu
|
0.314
|
–0.139
|
0.478
|
–0.429
|
–0.297
|
PC6
|
0.368
|
4.089
|
97.339
|
|
Cr
|
0.217
|
0.542
|
–0.355
|
0.224
|
–0.160
|
PC7
|
0.156
|
1.728
|
99.067
|
|
Mn
|
0.174
|
–0.127
|
0.546
|
0.609
|
–0.045
|
PC8
|
0.058
|
0.643
|
99.711
|
|
Co
|
0.489
|
0.142
|
0.035
|
–0.033
|
–0.243
|
PC9
|
0.026
|
0.289
|
100.000
|
|
Fe
|
0.393
|
–0.084
|
–0.461
|
0.092
|
–0.170
|
|
|
|
|
|
Eigenvalue
|
3.713
|
1.804
|
1.427
|
0.943
|
0.505
|
|
|
|
|
|
Variability (%)
|
41.26
|
20.05
|
15.86
|
10.48
|
5.61
|
|
|
|
|
|
Cumulative %
|
41.26
|
61.31
|
77.16
|
87.64
|
93.25
|