Estuarine, Coastal and Shelf Science 74 (2007) 539e548
www.elsevier.com/locate/ecss
Metals in suspended sediments from the Changjiang (Yangtze River) and
Huanghe (Yellow River) to the sea, and their comparison
Shuqing Qiao a,b, Zuosheng Yang a,*, Yanjun Pan c, Zhigang Guo a
a
Key Laboratory of Seafloor Science and Exploration Technology, Ocean University of China, College of Marine Geoscience,
238 Songling Road, Qingdao 266003, China
b
Key Laboratory of Marine Sedimentology and Environmental Geology, SOA, Qingdao 266061, China
c
Marine Geological Survey of Hainan Province, Haikou 570206, China
Received 16 March 2007; accepted 9 May 2007
Available online 16 July 2007
Abstract
Thirty-five samples of suspended sediments were collected at Datong Station and Lijin Station, the basin-wide control stations of the Changjiang (Yangtze River) and the Huanghe (Yellow River) during flood and dry seasons in 2000 and 2001. Concentrations of 15 elements (Fe, Mg,
Ca, Al, Na, K, Ti, Mn, Ba, Sr, Pb, Cu, Zn, V, and Ni) in these samples were measured by ICP-AES. The results indicated that Fe, Al, Ti, Mn, Ba,
Cu, Zn, V and Ni concentrations in the Changjiang sediments in May (flood season) were quite close to those in November (dry season), whereas
Mg, Ca, Na, K, Sr concentrations were slightly higher and Pb was relatively lower in the dry season. Ti, Ba, Sr and Zn concentrations in Huanghe
sediments varied little in August (flood season) and December (dry season), while Mg, Ca, Al, Na and K concentrations were higher by approximately 30% and Fe, Mn, Pb, Cu, Zn, V and Ni concentrations were lower in flood season. Concentrations of most metals, except Ca, Na and Sr
were much higher in Changjiang sediments than those in the Huanghe. Such differences of metal concentrations in sediments from these two
rivers could be ascribed to their different sediment sources and weathering processes within their corresponding river basin. Particularly, since
the 1980s, Pb and Zn concentrations in Changjiang sediments have increased significantly due to the releases of waste/contaminants from human
activities, while the variations for these two elements in the Huanghe samples were very little due to the elevated river bed in the lower reaches.
Ó 2007 Elsevier Ltd. All rights reserved.
Keywords: Changjiang (Yangtze River); Huanghe (Yellow River); suspended sediments; metals; sediment source
1. Introduction
Riverine sediments are products of bedrocks within the river
basin from continuous weathering and leaching processes, and
are closely associated with waste drainage (Qu and Yan, 1990;
Chen et al., 2000; Zhang and Liu, 2002), so compositions of
suspended sediments from rivers can provide information of
not only parent materials and climate type in the river basins,
but also impacts from human activities. Furthermore, these riverine sediments are major carriers of elements from the rivers
to the ocean, and have important influences on sedimentary
* Corresponding author.
E-mail address: [email protected] (Z. Yang).
0272-7714/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.ecss.2007.05.042
and ecological systems in the river estuary and adjacent coastal
ocean (Zhang, 1999; Zhang and Liu, 2002).
The Changjiang and Huanghe discharge 0.48 109 t and
1.1 109 t, respectively, of fine-grained sediments annually
to the oceans, accounting for 10% of the world’s annual sediment discharge (Milliman and Syvitski, 1992). This huge
amount of sediment is one of the major factors affecting the
balance of sedimentary and ecological environments in the
Bohai Sea, Yellow Sea and East China Sea (Alexander
et al., 1991; Zhang, 1999). Recently there has been a wide interest in element concentrations of surface sediment from
these two rivers. Recent studies show that Changjiang sediments are characterized by higher concentrations of K, Fe,
Al and most of trace elements, while Huanghe sediments
are relatively enriched in Ca, Na and Sr (e.g., Yang, 1988;
540
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
Zhang et al., 1998; Fan et al., 2001; Yang et al., 2002). The
geochemical characteristics of metals in suspended sediments
from the Changjiang and Huanghe was first documented in the
1980s (Li et al., 1984; Qu et al., 1984), which showed that the
characteristics of metals in suspended sediments from these
two river systems were quite different. Zhang and Huang
et al. in the 1990s published a series of papers about the chemical compositions of suspended sediments from the Changjiang and Huanghe and chemical flux into the coastal areas
(Huang and Zhang, 1990; Zhang et al., 1990a,b; Huang
et al., 1992; Zhang et al., 1994; Zhang, 1999; Zhang and
Liu, 2002). Their results showed that particulate metal levels
had close correlations with rock/soil compositions in the
drainage basins, and they were generally lower in the
Huanghe. Most of these studies were restricted to elemental
compositions of suspended sediments collected from these
two rivers during the period of 1980e1990. However, sediment discharge from the Changjiang and Huanghe has greatly
decreased, mostly due to the impact of dams since 1990 (Xu,
2003; Yang et al., 2006). The average annual sediment discharge of the Huanghe as recorded at Lijin Station during
the 2000e2004 period was only 22.7% of that in the 1980s
according to data from the Huanghe Water Conservation Commission (Wang et al., 2007). The average annual sediment discharge of the Changjiang as recorded at Datong Station during
the period from 2000 to 2004 decreased by more than 40% of
that in the 1980s according to data from the Changjiang Water
Conservation Commission (Yang et al., 2006). But the elemental concentrations and the seasonal differences of metal concentrations in the suspended sediments from these two rivers
in the years of sharp reduction of sediment discharge since
1990 have not been documented. Comparisons of metal
concentrations in these two rivers, and their control factors
have been of little concern until recently.
In this paper, 35 suspended sediment samples were collected at Datong Station and Lijin Station, the basin-wide control stations of the Changjiang and Huanghe, in different
seasons of 2000 and 2001. Based on the measurements in
the laboratory, metal concentrations in suspended sediments
from these two major rivers to the sea were presented and
compared with each other. Moreover, the seasonal changes
of metal concentrations in the suspended sediments were examined. The present results indicated that the metal concentrations in the suspended sediments from these two rivers were
closely associated with sediment source, weathering process
and human activities within different river basins.
2. Materials and methods
2.1. Sampling
Datong Hydrographic Station is located at the tidal limit of
the Changjiang estuary, approximately 650 km upstream from
the river mouth (Fig. 1). The water and sediment discharge recorded at Datong Station represent the standard figures from
the Changjiang to the sea (Yang et al., 2006). Lijin Hydrographic Station located 100 km upstream from the Huanghe
mouth is the last station before the river debouches into the Bohai Sea, and the records at Lijin represent the standard figures
from the Huanghe to the sea (Wang et al., 2006) (Fig. 1). Therefore, the suspended sediment samples collected from Datong
and Lijin Stations can be used to examine metal concentrations
in the suspended sediments from these two rivers to the sea.
Fig. 1. Map of the Changjiang and Huanghe basins, as well as Datong and Lijin Stations where suspended sediment samples were collected after Wang et al.
(2006). The dashed outline shows the drainage basin of the Changjiang and Huanghe. The color scale of the relief map indicates the land elevation above the
sea level in meter.
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
A total of 18 water samples were collected at sites located
90 m, 1050 m and 1590 m (marked with A, B and C) away
from the river bank along a transect across the Changjiang
river channel at Datong Station on November 27, 2000 and
May, 2001 (Fig. 2a). A total of 17 water samples from the
Huanghe were collected along a transect at sites located
70 m, 150 m and 180 m (marked with A, C and D) from the
river bank at Lijin Station on December 11, 2000 and August
24, 2001, respectively (Fig. 2b). Two additional sites were
chosen on December 11, 2000 at 120 m and 210 m (marked
with B and E) away from the bank along the same transect
of the Huanghe river channel at Lijin (Fig. 2b). Samples
through the water column were collected at depths of 0.5 m
(surface layer), 0.6 h (h: total water depth) (middle layer)
and 0.5 m from the bottom (bottom layer) at each site, and
the water layers were marked by the numbers of 0 for surface
layer, 1 for middle layer and 2 for bottom layer, respectively
(Fig. 2).
2.2. Analytical methods
Water samples were filtered with a micro-pore filter membrane with a pore diameter of 0.45 mm to acquire suspended
sediments. Grain-size composition of the filtered samples
was analyzed using Malvern Mastersizer 2000. Samples
were preprocessed using 10% H2O2 solution to decompose organic matter and then dispersed and homogenized using ultrasonic vibrator for 30 s before passing through the laser particle
size analyzer.
Element concentration was measured using ICP-AES at
Department of Chemical Engineering, Hong Kong University
of Science & Technology. These suspended sediments were
digested with HNO3-HF-HCl after being dried and weighed.
In order to monitor the analytical accuracy, standard samples
(BCCS1) and three blank samples were digested simultaneously. The solutions were analyzed with ICP-AES to determine the concentrations of 15 elements: Fe, Mg, Ca, Al, Na,
K, Ti, Mn, Ba, Sr, Pb, Cu, Zn, V, and Ni. The recoveries of
these elements were from 81% to 101% except for Ni (76%)
and Zn (135%). These 15 metals are reported as weight %
(Fe, Mg, Ca, Al, Na, K, Ti, Mn) or mg/g (Ba, Sr, Pb, Cu,
Datong station
Zn, V, Ni). Furthermore, statistical analysis including factor
analysis and cluster analysis were conducted using SPSS
11.5 (SPSS Inc.) to examine the relationships among these
metals as well as the relationship with their sources.
3. Results
3.1. Metals in suspended sediments from the Changjiang
As shown in Table 1, the concentrations of suspended sediments from Datong Station varied from 0.03 kg/m3 to
0.23 kg/m3 with averages of 0.16 kg/m3 in November and
0.07 kg/m3 in May, respectively. The grain-size composition
of the suspended sediments collected in November was generally similar to those in May. These sediments consisted mainly
of silt (51.06%e61.79%) and clay (38.08%e48.94%), and
were poorly sorted.
The major elements in suspended sediments from the
Changjiang were Fe (1.69e4.18%), Mg (0.51e1.57%), Ca
(0.57e2.54%), Al (3.24e7.96%), Na (0.04e0.37%), K
(1.12e3.07%), Ti (0.22e0.58%), and Mn (0.05e0.11%). Concentrations of Mg, Ca, Na, and K were higher in samples collected in November, while Fe, Al, Ti and Mn concentrations
had little seasonal difference. The concentrations of all determined elements were obviously lower in the samples of C17
and C18. Concentrations of most trace metals (Ba, Cu, V
and Ni) varied little in the samples of C1eC16 and had no evident seasonal change. Zn concentration was higher in the surface samples than those in the middle and bottom samples, and
the averages in November and May were 213.87 mg/g and
253.76 mg/g, respectively. Concentrations of Pb and Sr had
no significant variation in the suspended sediments through
the water columns at all sites, however the average concentration of Sr was 35.29 mg/g higher in November than that in
May, whereas the average concentration of Pb was 41.89 mg/g
higher in May than that in November (Table 1).
Three factors were extracted from factor analysis, covering
96% of the total variance (Table 2). Factor 1, which describes
55% of the variance, had high loadings for such heavy metals
and elements as Ba, Cu, V, Ni, Fe, Al, K, Ti and Mn. Parent
rock and weathering conditions may be the source of this
Lijin station
B
A
0
C
0
0
A
Water level
0.5
2
1
2
1
2
Depth (m)
Depth (m)
1
10.0
20.0
541
C D E
B
0
0
0
1
1.0
2
1.5
2.0
0
Water level
0
2
2
2
2
2.5
(a)
(b)
Fig. 2. Sampling transects and sites of suspended sediments at Datong (a); and Lijin (b) Stations. Samples from Datong station were collected at sites located 90 m,
1050 m and 1590 m (marked with A, B and C) away from the river bank along a transect, and samples from Lijin at sites located 70 m, 120 m, 150 m, 180 m and
210 m away from the river bank. Water samples along the water column were collected at depths of 0.5 m (surface layer), 0.6 h (h: total water depth) (middle layer)
and 0.5 m from the bottom (bottom layer) at each site, and marked by 0, 1 and 2, respectively.
542
Table 1
Elemental and grain-size compositions of suspended sediments collected at Datong Station from the Changjiang in November, 2000 and May, 2001
Cruise
Sampling Water layer Turbidity Concentration (mg/g)
sitea
(kg/m3)
Ba
Sr
Pb
C1 11-2000 A
C2 11-2000
C3 11-2000
C4 11-2000 B
C5 11-2000
C6 11-2000
C7 11-2000 C
C8 11-2000
C9 11-2000
Average in November
C10 05-2001 A
C11 05-2001
C12 05-2001
C13 05-2001 B
C14 05-2001
C15 05-2001
C16 05-2001 C
C17 05-2001
C18 05-2001
Average in May
Average in the study
Coefficient of variation
a
b
surface
middle
bottom
surface
middle
bottom
surface
middle
bottom
surface
middle
bottom
surface
middle
bottom
surface
middle
bottom
0.14
0.21
0.23
0.13
0.15
0.15
0.1
0.13
0.17
0.16
0.08
0.11
0.05
0.06
0.07
0.03
0.06
0.07
0.11
0.07
0.11
48.48
468.18
442.48
485.33
531.14
501.65
536.71
537.01
560.78
488.69
505.77
535.85
526.04
509.52
538.2
533.76
544.56
531.45
363.92
215.36
477.63
491.70
16.94
94.25
108.12
109.32
110.49
103.48
105.51
109.43
111.21
103.19
106.11
80.48
81.44
82.3
76.83
77.68
81.38
72.51
51.9
32.9
70.82
88.47
24.77
47.74
48.07
51.44
64.33
107.95
67.11
57.76
67.16
74.12
65.08
76.12
73.71
68.74
150.29
93.36
135.11
217.08
108.13
40.2
106.97
86.02
51.69
Weight %
Fe
Zn
V
Ni
56.64
59.86
62.27
62.94
60.22
61.11
67.53
54.73
62.48
60.86
53.45
55.73
59.46
59.38
51.87
61.79
71.54
40.67
23.25
53.02
56.94
18.75
308.6
193.85
182.77
246.19
183.51
190.95
202.87
208.49
207.62
213.87
239.17
209.45
194.06
265.33
208.68
248.8
534.07
261.22
123.02
253.76
233.81
36.5
105.83
117.09
120.24
122.1
119.69
118.57
133.33
111.86
119.52
118.69
105.82
119.11
122.77
119.68
117.15
125.22
118.41
80.38
48.43
106.33
112.51
17.23
36.12 3.42 1.32 2.12 6.16 0.26 2.41 0.46 0.09 0
40.34 4.09 1.57 2.35 7.1
0.35 2.84 0.58 0.11 0
39.69 4.03 1.56 2.5
7.32 0.36 3.05 0.56 0.11 0
42.89 4.01 1.54 2.5
7.41 0.37 3.04 0.55 0.1
0
38.82 4.03 1.5
2.09 7.32 0.34 3.04 0.54 0.1
0
41.46 4.04 1.52 2.18 7.33 0.36 2.99 0.55 0.1
0
43.96 4.18 1.54 2.31 7.61 0.32 3.07 0.55 0.1
0.05
38.89 3.96 1.51 2.54 7.23 0.34 2.96 0.54 0.1
0
39.78 3.9
1.46 2.29 7.1
0.33 2.94 0.53 0.1
0.04
40.22 3.96 1.50 2.32 7.18 0.34 2.93 0.54 0.10 0.01
34.01 4.01 1.19 1.09 7.95 0.2
2.82 0.52 0.1
0.13
39.1
4.05 1.16 0.99 7.94 0.23 2.89 0.54 0.11 0.14
40.28 3.97 1.14 0.89 7.77 0.3
2.99 0.54 0.11 0.13
41.75 4.03 1.13 1.2
7.96 0.05 2.81 0.51 0.1
0.14
40.88 3.98 1.12 0.99 7.91 0.19 2.83 0.51 0.1
0.12
40.37 4.1
1.17 1.17 7.86 0.22 2.81 0.52 0.11 0.13
41.94 4.01 1.14 1.34 7.66 0.06 2.64 0.49 0.1
0.04
27.75 2.68 0.76 0.73 5.14 0.08 1.87 0.34 0.07 0.06
15.01 1.69 0.51 0.57 3.24 0.04 1.12 0.22 0.05 0.11
35.68 3.61 1.04 1.00 7.05 0.15 2.53 0.47 0.09 0.11
37.95 3.79 1.27 1.66 7.11 0.24 2.73 0.50 0.10 0.06
17.93 16.54 23.2 42.82 16.81 48.06 18.11 17.48 15.51 97.86
The sampling site were marked with A, B and C for 90 m, 1050 m and 1590 m away from the river bank, respectively.
Mz: mean grain-size.
Mg
4
%
Cu
Ca
Al
Na
K
Ti
Mn
sand
silt
clay
Mzb
56.96
57.91
56.77
53.84
55.66
54.4
55.46
51.06
57.47
55.50
58.87
59.9
61.79
58.97
56.85
58.36
54.83
56.79
56.93
58.14
56.82
4.31
43.04
42.09
43.23
46.16
44.34
45.6
44.49
48.94
42.49
44.49
41
39.96
38.08
40.89
43.03
41.51
45.13
43.15
42.96
41.75
43.12
5.78
7.8
7.75
7.78
7.86
7.85
7.85
7.83
7.88
7.75
7.82
7.81
7.77
7.72
7.8
7.85
7.81
7.89
7.87
7.87
7.82
7.82
0.64
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
No.
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
Table 2
Varimax rotated loadings and communalities for Changjiang suspended
sediments (n ¼ 18)
Element
Factor 1 Factor 2 Factor 3 Communalities (h2)
Ba
0.91
Sr
0.56
Pb
0.24
Cu
0.77
Zn
0.10
V
0.91
Ni
0.88
Fe
0.94
Mg
0.57
Ca
0.19
Al
0.98
Na
0.40
K
0.91
Ti
0.89
Mn
0.94
Explained variance (%) 55.16
0.20
0.81
0.35
0.47
0.02
0.35
0.38
0.31
0.81
0.97
0.07
0.74
0.40
0.43
0.24
26.35
0.19
0.16
0.85
0.38
0.96
0.12
0.21
0.10
0.10
0.07
0.13
0.47
0.05
0.06
0.00
14.49
0.907
0.995
0.901
0.956
0.930
0.966
0.955
0.992
0.989
0.977
0.988
0.938
0.986
0.985
0.935
96
factor. Factor 2, with high loadings of the active elements Sr,
Mg, Ca and Na, accounted for 26% of the total variance. This
factor source could be due to weathering conditions. Pb and
Zn described 14% of the total variance, thus comprising the
third factor, whose source could be anthropogenic.
3.2. Metals in suspended sediments from the Huanghe
At Lijin Station, the concentrations of suspended sediments
varied from 0.52 kg/m3 to 2.33 kg/m3, higher than those from
Datong Station. Similar to those from Datong Station, sediment concentrations were of seasonal variety and seemed to
be higher in dry seasons than in flood seasons. Suspended sediments collected in December were composed mainly of silt
(67.19%) and clay (32.00%). Compared with those in December, suspended sediments in August were characterized by
higher sand and lower silt and clay constituents with averages
of 30.97%, 56.62% and 12.37%, respectively, and were more
poorly sorted (Table 3).
Concentrations of Mg, Ca, Al, Na and K were found to be
relatively higher in samples collected in August than those collected in December, while concentrations of Fe, Mn, Pb, Cu, V
and Ni were relatively lower, and Ti, Ba, Sr and Zn concentrations were similar in all samples. The concentrations of Mg,
Ca, Al, Na and K were positively related with coarse fractions,
whereas Fe, Mn, Pb, Cu, V and Ni were negatively related to
the coarse fractions, suggesting that grain-size had distinct impact on element concentrations in suspended sediments from
the Huanghe.
Using factor analysis, three factors for Huanghe samples
were extracted, which accounted for 35%, 35% and 24%, respectively, of the total variance. Factor 1 had high positive
loadings of heavy metals of Pb, Cu, Zn, V and Ni that were
positively correlated with each other, indicating that this factor
could be named as a source factor. Factor 2 had high positive
loadings of Sr, Ca, Mg, Al, Na and K. This factor source could
be explained by contributions mainly from sources and
543
chemical weathering conditions. Factor 3 had high loadings
of Fe, Ti and Mn, and the factor source was parent material
(Table 4).
3.3. Comparison of metals between Changjiang and
Huanghe suspended sediments
The Changjiang suspended sediments were characterized
by relatively higher heavy metals concentrations (e.g. Pb,
Cu.), while the suspended sediments from the Huanghe
were enriched in Ca, Na and Sr (Fig. 3). This result was similar to that in the previous studies (Li et al., 1984; Yang, 1988;
Yang et al., 2002). Sediment composition (i.e. grain-size and
mineralogy) could account for 80e90% of metal concentrations in the Changjiang estuary (Zhang, 1999). In both the
flood and dry seasons for Changjiang, grain-size compositions
of suspended sediments were similar, while the concentrations
of Mg, Ca, Na, K, Pb and Sr were clearly different, thus it
could be concluded that variation of metal concentrations
was not induced by the difference in grain-size. In contrast,
Mg, Ca, Na, etc. concentrations in the Huanghe suspended
sediments varied largely in different seasons, illustrating the
impact of grain-size on metal concentrations. Generally, the
concentrations of Fe, Mn, Pb, Cu, V and Ni had negative correlation with mean grain-size (Mz), but concentrations of Mg,
Ca, Al, Na and K were positively correlated with Mz.
Based on Q-mode cluster analysis the suspended sediments
from the Changjiang and Huanghe could be classified into two
main groups at a distance of 12.7 (Fig. 4). The first main group
consisted of 17 samples from the Huanghe and two samples
from the Changjiang. Except Ca, Na and Sr, the metal concentrations were lower in these samples compared with the remaining samples. The second group was comprised of 16
samples from the Changjiang, and samples collected in November and May were clustered into two sub-groups, with
some outliers. Cluster analysis confirmed the differences in
metal concentrations between the Changjiang and Huanghe
samples and showed that metal concentrations in samples
from these two rivers had seasonal changes. Fig. 3 shows
the changes of elemental concentrations in suspended sediments collected from the Changjiang and Huanghe during
the past 20 years. Compared with data in 1980s, the concentrations of metals in the Huanghe suspended sediments varied little (e.g. Pb, Cu, Zn, Al.) or slightly decreased (Ba, Sr, Fe,
Mg, Ca.). Pb and Zn concentrations in the Changjiang suspended sediments showed substantial increase from ca.
50.80 mg/g and 114.55 mg/g to 86.02 mg/g and 233.81 mg/g, respectively, during the past two decades. While Ba, Sr, V, Ni,
Fe, Ca, and Na decreased slightly and Cu, Mg, Al, K, Ti,
and Mn varied little.
4. Discussion
4.1. Sources and weathering conditions
The range of the Huanghe drainage basin is 32 e42 N and
95 e120 E with the drainage area of 750,000 km2.
544
Table 3
Elemental and grain-size compositions of suspended sediments collected at Lijin Station from the Huanghe in December, 2000 and August, 2001
Cruise
Sampling
sitea
H1
12-2000 A
H2
12-2000
H3
12-2000 B
H4
12-2000
H5
12-2000 C
H6
12-2000
H7
12-2000 D
H8
12-2000
H9
12-2000 E
H10 12-2000
Average in December
H11 08-2001 A
H12 08-2001
H13 08-2001 C
H14 08-2001
H15 08-2001
H16 08-2001 D
H17 08-2001
Average in August
Average in this study
Coefficient of variation
a
b
4
Water
layer
Turbidity
(kg/m3)
Ba
Sr
Pb
Cu
Zn
V
Ni
Fe
Mg
Ca
Al
Na
K
Ti
Mn
sand
silt
clay
Mzb
surface
bottom
surface
bottom
surface
bottom
surface
bottom
surface
bottom
1.36
1.45
1.61
1.84
1.83
2.07
1.43
2.33
1.26
1.56
1.67
0.87
1.12
0.52
0.71
0.7
0.65
0.68
0.75
1.29
42.23
315.98
391.15
256.42
487.47
425.19
328.79
327.89
272.39
335.24
289.37
342.99
359.21
349.23
386.8
458.52
427.06
409.47
363.54
393.4
363.75
17.75
129.92
177.2
115.05
173.41
144.6
131.07
151.33
114.29
159.13
139.04
143.5
146.82
141.23
160.93
169.28
166.84
159.34
146.8
155.89
148.6
12.71
18.45
27.3
18.53
17.14
12.81
21.08
24.32
13.08
19.53
21.59
19.38
10.64
11.92
12.64
10.13
9.23
11.67
9.49
10.82
15.86
35.13
25.75
29.61
22.15
21.31
18.98
20.9
25.96
17.98
22.8
24.46
22.99
11.36
12.03
16.04
12.24
12.87
16.11
12.51
13.31
19
30
79.93
130.71
54.43
66.34
55.36
83.61
105.23
49.77
70
72.41
76.78
80.72
73.61
46.05
75.01
70.8
76.62
67.42
70.03
74
27.45
77.34
90.69
59.17
60.69
55.03
73.82
83.41
48.72
64.76
66.54
68.02
45.53
42.82
54.54
49.22
51.35
51.13
46.86
48.78
60.1
23.45
28.64
33.17
19.68
21.19
19.81
26.15
32.52
15.71
21.31
21.04
23.92
15.35
13.06
18.49
16.71
17.77
16.77
16.53
16.38
20.82
28.53
2.66
3
2.12
3.54
3.23
2.4
2.35
1.93
2.41
2.38
2.6
1.65
1.55
1.89
1.99
1.99
1.89
1.69
1.81
2.27
24.81
0.51
1.09
0.36
0.98
0.46
0.42
0.99
0.45
1.06
0.71
0.7
0.81
0.79
0.94
0.96
0.96
0.93
0.87
0.89
0.78
31.59
1.88
3.27
1.8
3.76
2.48
2.19
2.69
2.03
2.67
2.13
2.49
2.52
2.52
3.03
3.27
3.22
3
2.74
2.9
2.66
20.7
2.14
4.23
2.13
3.86
2.26
2.61
3.95
2.81
4.02
3.08
3.11
4.4
4.28
4.75
4.89
4.88
4.68
4.46
4.62
3.73
26.86
0.52
0.69
0.45
0.79
0.61
0.68
0.73
0.59
0.74
0.65
0.65
1.24
1.18
1.19
1.3
1.26
1.18
1.15
1.21
0.88
34.23
2.24
2.57
0.79
1.81
1.6
1.19
2.37
1.5
2.35
1.65
1.81
2.36
2.28
2.21
2.34
2.3
2.22
2.19
2.27
2
24.62
0.27
0.32
0.24
0.38
0.36
0.3
0.28
0.24
0.28
0.28
0.3
0.27
0.24
0.29
0.32
0.31
0.29
0.27
0.28
0.29
13.41
0.06
0.07
0.05
0.08
0.07
0.05
0.05
0.04
0.06
0.05
0.06
0.04
0.04
0.05
0.05
0.05
0.05
0.04
0.05
0.05
21.91
0.29
0.27
0.39
0.5
0.46
3.73
0.37
1.3
0.4
0.38
0.81
35.33
37.2
23.53
31.22
32.73
27.94
28.86
30.97
13.23
117.8
64.98
66.32
66.38
67.7
66.2
69.13
68.16
69.67
66.37
66.97
67.19
54.36
53.04
61.07
56.38
52.62
60.81
58.08
56.62
62.84
9.35
34.73
33.41
33.23
31.79
33.34
27.14
31.47
29.03
33.23
32.65
32
10.07
9.76
15.4
12.39
14.65
11.25
13.06
12.37
23.92
42.62
7.13
7.11
7
6.93
7.01
6.58
6.94
6.71
6.99
6.98
6.94
4.3
4.24
4.89
4.38
4.83
4.51
4.5
4.52
5.94
20.9
surface
bottom
surface
middle
bottom
surface
bottom
Concentration (mg/g)
Weight %
%
The sampling site were marked with A, B, C, D and E for 70 m, 120 m, 150 m, 180 m and 210 m away from the river bank, respectively.
Mz: mean grain-size.
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
No.
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
Table 4
Varimax rotated loadings and communalities for Huanghe suspended sediments (n ¼ 17)
Element
Factor 1 Factor 2 Factor 3 Communalities (h2)
Ba
Sr
Pb
Cu
Zn
V
Ni
Fe
Mg
Ca
Al
Na
K
Ti
Mn
Explained variance (%)
0.31
0.05
0.95
0.92
0.75
0.97
0.95
0.50
0.09
0.13
0.30
0.62
0.09
0.05
0.42
34.64
0.59
0.85
0.15
0.27
0.49
0.03
0.01
0.22
0.94
0.78
0.93
0.74
0.89
0.21
0.03
34.55
0.72
0.51
0.06
0.19
0.06
0.14
0.16
0.82
0.14
0.56
0.07
0.14
0.08
0.95
0.88
23.81
0.957
0.979
0.931
0.952
0.805
0.969
0.926
0.978
0.904
0.939
0.968
0.957
0.798
0.943
0.945
93
Approximately 90% of the Huanghe sediment is derived from
the Malan Loess distributed along its middle reaches (Ren and
Shi, 1986). Consequently, the Huanghe suspended sediments
inherit characteristics of the loess with high concentrations
of Ca, Na and Sr (Yang, 1988). Ti is usually used as criterion
to evaluate the differences in abundance of elements due to its
chemical stability (Shotyk et al., 2003). A coefficient RL was
defined to characterize the relationship of suspended sediments from the Changjiang and Huanghe with the loess (Wu
et al., 1995), which was calculated as:
RL ¼ ðX=TiÞsample =ðX=TiÞloess
where X is the concentration of other elements and Ti is the
concentration of Ti in the Changjiang or Huanghe suspended
sediments and the loess. As shown in Fig. 5, RLs of the
Huanghe sediments, ranging from 0.6 to 1.4, were much closer
to 1, compared with those of the Changjiang varying between
0.1 and 2.5, which suggested that metal concentrations in the
Huanghe sediments were similar to that of the loess. Changjiang sediments consisted of complex sources and were mainly
from the upper reaches through tributary inflow of the Jinshajiang, Jialingjiang and the middle reaches of the Hanjiang
(Chen et al., 2002). Igneous rocks and various ore deposits
were ubiquitous in the Changjiang basin, so Changjiang sediments were characterized by high Fe-group and Cu-group elements with high background levels of Fe, Ti, Mn, V, Ni, Cu,
Pb, and Zn (Yang et al., 2002).
Al is the second most abundant metal in the earth’s crust
and combined closely with fine-size fraction. In addition Al
mostly resides in aluminum-silicates and its migration capability is low. Al is mostly used as a reference element to normalize metal concentration (e.g., Schropp and Windom, 1988).
The M/Al rations in the Changjiang suspended sediments
are higher than those in the Huanghe (Fig. 6). This confirms
that the suspended sediments from the Changjiang are more
enriched in Pb, Cu, Zn and Ni than those from the Huanghe.
The Huanghe drainage basin is located in a temperate
and semi-arid climate zone with annual precipitation of
(b)
700
600
500
1980
Aug., 1981
1984-1986
Nov., 2000
May, 2001
Weight %
Concentration (µg/g)
(a)
400
300
200
100
0
Ba
Sr
Pb
Cu
Zn
V
10
9
8
7
6
5
4
3
2
1
0
Fe
Ni
Sep., 1981
600
1984-1986
Dec., 2000
500
Aug., 2001
Weight %
Concentration (µg/g)
Jul.,1980
400
300
200
100
0
Ba
Sr
Pb
Cu
Elements
Aug., 1981
1984-1986
Nov., 2000
Mg
Ca
Al
Na
K
Ti
Mn
Elements
(d)
700
1980
May, 2001
Elements
(c)
545
Zn
V
Ni
10
9
8
7
6
5
4
3
2
1
0
Jul.,1980
Sep., 1981
1984-1986
Dec., 2000
Aug., 2001
Fe
Mg
Ca
Al
Na
K
Ti
Mn
Elements
Fig. 3. Comparisons of metal concentrations in suspended sediments from the Changjiang ((a) and (b)) and Huanghe ((c) and (d)) during 1980e2001. Note that the
suspended sediments from the Changjiang are enriched in most metals except Ca, Na and Sr; Pb and Zn increase clearly in the Changjiang samples during the past
20 years, while metal concentrations vary little in the Huanghe samples. Data in 1980, 1981 and 1984e1986 are from Qu et al. (1984), Li et al. (1984) and Zhang
et al. (1995), respectively.
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
546
Dendrogram using Complete Linkage
Rescaled Distance Cluster Combine
CASE
Label
0
5
10
15
20
25
Hh14
Hh15
Hh13
Hh16
Hh11
Hh17
Hh12
Hh7
Hh9
Hh2
Hh4
Hh3
Hh8
Hh6
Hh10
Hh1
Hh5
Chj17
Chj18
Chj13
Chj15
Chj11
Chj12
Chj10
Chj14
Chj2
Chj3
Chj4
Chj6
Chj7
Chj5
Chj9
Chj8
Chj1
Chj16
Fig. 4. Q-cluster analyses of suspended sediments from the Changjiang and
Huanghe.
600e800 mm, of which 70e80% is from July to September
(Ren and Shi, 1986). Zhang et al. (1995) indicated that the
physical erosion rate in the Huanghe basin was w1.4 106 kg km2y1, while the chemical erosion rate of 25 103 kg km2 y1 was relatively weak. Low chemical erosion
rate and precipitation are propitious to the preservation of minerals (carbonate, smectite, etc.), resulting in less leaching of
alkaline and alkaline earth metals (Ca, Sr and Na) and their
relatively higher concentrations in the suspended sediments
from the Huanghe (Fig. 3). Furthermore, concentrations of
active elements such as Mg, Ca, Na and K were positively
correlated with Al in the Huanghe suspended sediments,
which could be ascribed to the relatively weak chemical
weathering process. The Changjiang drains through a region
of temperate to subtropical monsoon climate zone with precipitation of 1000e1200 mm annually, where the climate is much
warmer and wetter than that along the Huanghe basin (Chen
et al., 2002). Consequently, the chemical erosion rate in the
Fig. 5. RL values of samples collected at Datong Station from the Changjiang
and Lijin Station from the Huanghe. RL represents relationship between samples and loess; the data of elemental concentration in the loess are quoted from
Wu et al. (1995).
Changjiang basin is 104 103 kg km2 y1, which is 79 103 kg km2 y1 higher than that in the Huanghe basin (Li
et al., 1984). The degree of chemical weathering can be estimated by the chemical index of alteration (CIA) (CIA ¼
Al/(Al þ Ca þ Na þ K)), SF (SF ¼ ((Fe þ Al)/(Ca þ K þ
Na þ Mg)) and ratios of K/Ca, Al/Na and K/Na according
to their different mobility during chemical weathering and
different occurrences in minerals. Generally, Ca is mostly enriched in calcite, dolomite and plagioclase, and Na is primarily
resides in plagioclase. K resides mostly in K-feldspar and
partly in illite and mica. They are all active metal, whereas
Fe and Al are inert elements. The values of CIA, SF and ratios
of K/Ca, Al/Na and K/Na in the suspended sediments from the
Changjiang were clearly higher than those from the Huanghe
(Fig. 7). This indicated that chemical weathering in the Changjiang basin was more intensive. As a result, more alkaline and
35
Chj 1980
Chj 2000-2001
Hh 1980
Hh 2000-2001
30
25
20
15
10
5
0
Pb/Al
Cu/Al
Zn/Al
Ni/Al
Fig. 6. Metal-to-Al (M/Al) ratios of suspended sediments from the Changjiang
and Huanghe. Data of metal concentrations in 1980 are from Qu et al. (1984).
S. Qiao et al. / Estuarine, Coastal and Shelf Science 74 (2007) 539e548
Compared with data from the 1980s, Pb and Zn concentrations
increased distinctly (Fig. 3); Fig. 7 shows that Pb/Al and Zn/Al
rations are higher than those in the 1980; in addition, Pb and Zn
were anthropogenic based on factor analysis (Table 2), possibly
indicating that the impact of human activities on Pb and Zn
concentrations in the Changjiang basin is significant.
50
45
Chj
547
Hh
40
35
30
25
20
5. Conclusions
15
10
5
0
CIA
SF
K/Ca
K/Na
Al/Na
Fig. 7. CIA, SF, K/Ca, K/Na and Al/Na in the Changjiang and Huanghe suspended sediments. The higher values of CIA, SF, K/Ca, K/Na and Al/Na in the
Changjiang sediments indicate stronger chemical weathering in the drainage
basin.
alkaline earth metals were leached in Changjiang sediments,
while Al and heavy metals relatively enriched.
4.2. Anthropogenic impacts
Sediment discharges from the Changjiang and Huanghe
have been sharply decreased since 1990 due to dam construction and natural impact (Xu, 2003; Yang et al., 2006). The average annual sediment discharge of the Huanghe recorded at
Lijin Station was 0.639 109 t in the 1980s, verses
0.145 109 t during the period of 2000e2004 according to
the data from the Huanghe Water Conservation Commission.
While the amount of waste water discharge increased sharply
from ca. 2.0 109 t/yr in the 1980s to 4.18 109 t/yr during
the above period (Huanghe Water Resources Commission,
2000e2004). It has been found that the concentrations of
metals in the Huanghe suspended sediments had been stable
in the past 20 years, with slight fluctuations (Fig. 3). Furthermore, M/Al ratios vary little in the Huanghe suspended sediments during the past 20 years (Fig. 6). Two reasons can
explain this: First, the lower reaches of the Huanghe downstream of the Taohuayu Station (Fig. 1) is characterized by
unique elevated riverbed above the surrounding area. Therefore the surrounding landscape cannot drain into the river
nor can tributaries enter, preventing pollutants from entering
the Huanghe to some extent. Second, the pollutants released
from the upper and middle reaches are absorbed by the large
amount of suspended sediments, precipitate and are deposited
as hydroxides/oxides due to the high pH values (Huang et al.,
1992).
During 2000e2004, an average of ca. 0.25 109 t/yr of
sediment was discharged past the Datong Station, a decrease
by more than 40% of the level in 1980s, whereas water discharge
has not appeared decrease (Yang et al., 2006), with increasing
ore fields, industrial factories and residents in the Changjiang
basin. Waste water discharge along the Changjiang was
127 109 t in the early 1980s, which increased to 234 109 t
in 2000 (Changjiang Water Resources Commission, 2000).
Variation of metal concentrations in suspended sediments
from the Changjiang and Huanghe can reflect contributions
of parent material, weathering process and anthropogenic activities along their drainage basins. Suspended sediments
from the Changjiang had higher concentrations of most metals
compared with those from the Huanghe, due to widespread ore
deposits and relatively strong chemical weathering. Seasonal
variations of most metal concentrations in Changjiang suspended sediments were not as obvious as those in the Huanghe
sediments, with seasonal differences between dry and flood
seasons less than 15%. Furthermore, comparison with data
in 1980s showed that the Changjiang had been polluted by
Pb and Zn due to human activities in the past 20 years. In contrast, suspended sediments from the Huanghe were characterized by higher concentrations of Ca, Na and Sr, which were
related to loess deposits and relatively weak chemical weathering processes in the river basin. Seasonal differences in most
metal concentrations of the Huanghe samples were more than
20%, and as much as 60% due to the effect of grain-size.
Moreover, anthropogenic impacts on metals concentrations
in the Huanghe samples were not obvious in the last 20 years.
Acknowledgements
We are grateful to the anonymous reviewers whose constructive comments were critical to improving the scientific
quality of our original manuscript. We thank Professor Dejiang Fan from OUC for sample collections. We thank Dr.
Baozhu Liu from LSU, USA and Dr. Houjie Wang from
OUC, China for their help in polishing the manuscript. This
work is supported by the National Natural Science Foundation
of China (Grant No. 2002CB412404 and 90211022).
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