The Clam Pseudodontpsis euphraticus (Bourguignat,
1852) as a Bioaccumulation Indicator Organism of
Heavy Metals in Euphrates River-Iraq
Jasim Mohammed Salman
Biology Dep./ Coll. of Science/Babylon
University-Iraq
Abstract
The Fresh Water Clam Pseudodontpsis euphraticus (Bourguignat, 1852) used as bioindicator to
study the Bioaccumulation of some heavy metals into food chain in Euphrates river in mid. Of Iraq.
This study deals with nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in the aquatic
system: water-sediments-clam to investigate bioaccumulation of this metals by use fresh water clam
Pseudodontpsis euphraticus from Euphrates river in middle of Iraq seasonally from Spring 2005 to
Winter 2006. The heavy metals were studded in dissolved and particulate phase of water and in
exchangeable and residual phase of sediments and in soft tissues of clam. Heavy metals accumulated
according the system: water-sediment-clam because filter-feeding of this aquatic organism, and
recorded bioaccumulation factor: 16.81, 20.73, 12.36, 12.44, 15.79, 15.06, 12.8, 12.04, 15.69
respectively.
Keyword: Bioaccumulation, Heavy metals, Water pollution, Sediment, clam Pseudodontopsis
euphraticus.
‫الخالصة‬
‫ الواسع االنتشار في ميياه ن ير التي ار في المنلوية الوسيل‬Pseudodontopsis euphraticus ‫استخدم محار المياه العذبة‬
.‫وسط العراق‬- ‫من العراق كمؤشر لدراسة تراكم بعض العناصر الثويلة من خالل سلسلة غذائية ف ن ر الت ار‬
‫ محيار ليييان التيراكم‬- ‫ رواسي‬- ‫) في النايام المائ اميا‬Cd,Co,Cr,Cu,Fe,Mn,Ni,Pb,Zn
‫تم دراسة تسيعة نناصير ثويلية‬
‫ مين ن ير التي ار وسيط العيراق بصيورة فصيلية‬Pseudodontopsis euphraticus ‫الحيوي ل ذه العناصر باستخدام محار المياه العذبية‬
‫وفي‬
‫واليدمائو مين الميا وفي ال يل المتبيادل والمتبوي مين الرواسي‬
‫العناصير في ال يل اليذائ‬
‫إذ درسي‬,2006 ‫شيتا‬-2005 ‫من ربييع‬
‫وا ر إن تراكم العناصر يتبع الناام التصانديا‬.‫األنس ة الرخوة للمحار‬
.‫الدراسة‬
‫ للكائن المائ تح‬Filter-feeding ‫ومد يكون ذلك بتعل التغذية الترشيحية‬, ‫– محار‬
‫ رواس‬- ‫ما‬
‫ (ف أنس ة المحار والذي كانا‬Zn,Pb,Ni,Mn,Fe,Cu,Cr,Co,Cd ‫ للعناصر‬B.A.F. ‫معامل التراكم الحيوي‬
‫تم حسا‬
. ‫ ) مره بودر تركيلها ف الما نل التوال‬16.81,20.73,12.36,12.44,15.79,15.06,12.8,12.04,15.69
Introduction
Heavy metals occur in aquatic systems from natural sources and anthropogenic
activities. The pollution of aquatic environment by heavy metals affects aquatic biota
posses considerable environmental risks and concerns (Amisah et al., 2009).
Compared with other types of aquatic pollution, heavy metal pollutants less visible
but its effects on the ecosystem and humans are intensive and very extensive due to
their toxicity and their ability to accumulate in the biota (Shanmugam et al., 2007;
Edem et al., 2008).
The analysis of water and sediment samples does not allow for the estimation of
the quality of the metal which is biologically available (Etim et al., 1991).
Bivalves are effective biomonitors and have been widely used for heavy metal
monitoring purposes worldwide due to their ability to accumulate different chemicals,
long life span, high density and sessile (Otchere, 2003 ; Rainbow, 2007).
Aquatic invertebrates as bivalves take up and accumulate trace metals whether
essential or not, all of which have the potential to cause toxic effects; the body
concentrations of accumulated heavy metals show enormous variability across metals
and aquatic organism taxa (Rainbow, 2007).
884
Journal of Babylon University/Pure and Applied Sciences/ No.(3)/ Vol.(19): 2011
Any aquatic bivalves will take up heavy metals into the body from solution
through permeable body surface and from gut and that uptake of metals from water,
sediment and diet (Wang, 2002), or by biosorption (Soliman, 2006). The
accumulation of metals in bivalves is variable according to age and sex of organism
and temperature and salinity of water (Barsytelovjoy, 1999).
Metal concentrations in aquatic mollusks are influenced by many external factors
such as season, pH, hardness of water, concentration and composition of particulate
matter (Barsytelovejoy, 1999). Accumulated metal that has been detoxified and metal
that is available metabolically to play an essential and in extreme circumstances a
toxic role in biochemistry (Rainbow, 2002). Many studies deal with the
bioaccumulation of heavy metals in aquatic mollusks (e.g. clam, oysters & other) in
different aquatic systems and in many sites of world such as (Demina et al., 2009;
Netpae & Phalaraksh, 2009; Amisah et al., 2009; Shanmugam et al., 2007; Liu et al.,
2007; Turkmen et al., 2005; Ohimain et al., 2008; Gaber et al., 2008; Salman, 2006).
The aim of this study is to evaluate the seasonal bioaccumulation of nine heavy
metals in dissolved and particulate phase of water and residual and exchangeable
phase of sediments and soft tissue of fresh water clam Pseudodontopsis euphraticus
(Bourguignat, 1852) living in Euphrates river in middle of Iraq .
Material & Methods
Fresh water clam Pseudodontopsis euphraticus collected from Euphrates river (in
middle of Iraq) near Hindia, Kafel, and Kufa Townes, during Spring 2005 to Winter
2006.
After all samples were removed from the substratum with a new stainless steel
scraper, they were washed with clean river water at the site of collection, separated to
species, placed in a clean plastic bag and transferred in a cool box to laboratory at the
same day and then frozen at( -20 C°) until dissection (Turkmen et al., 2005). All
bottles were cleaned with 10% HNO3 then rinsed with distilled water prior to use.
Clam samples were cleaned to remove mud and debris and subsequently washed
with double distilled water, specimens were divided according to their size and 25
individual were obtained for each size class. There were (3) replicates for clam under
study. Soft tissue of clam dried at 40-45 C° in overnight. The extraction and
determination of heavy metals in clam soft tissues doing according to (Davies et al.,
2006).
Water samples were collected from same site of clam collection by polyethylene
bottles in 3 L to replicate and filtration by Millipore filter paper 0.45 µm, 47 mm
diameter and preconcentration according to (Riley & Taylor, 1968), to determined
the concentration of dissolved heavy metals.
Filter paper digested to determined the particulate heavy metals in water
(Sturgeon, 1982). Sediment samples collected from the region near clam by Grab
sampler, surface layer to 5 cm used to study of exchangeable and residual of heavy
metals in these sediments according to (Madkour, 2005).
The analytical blanks were run in the same way as the samples and concentrations
were determined using standard solutions prepared in the same acid matrix (Turkmen,
2003).
Concentrations of heavy metals in water, sediments and soft tissues of clam were
determined using pyeunicam Sp9 air-acetylene scientific model of flame atomic
absorption spectrophotometer (FAAS).
Bioaccumulation factor determined according to (Demina et al., 2009) as:
885
conc. of metals in clam ( g/g)
conc. of metals in water ( g/L)
Statistical variation analysis and correlation coefficient (r) were obtained.
B.A.F. 
Results & Discussion
Tables (1, 2) and Fig.(1;2) showed the seasonal concentrations and yearly
average of nine heavy metals studied in ecosystem of water, sediments and soft tissue
of fresh water clam P.euphraticus. The dissolved concentrations of heavy metals
under study in water ranged between 0.5 µg/L of Ni as lowest metal levels and 124
µg/L of Fe as highest metal levels. The study found highly variation in heavy metals
concentration between different season in same metal or different metals, may be due
to variation of heavy metals pollution source and differ of amount discharge to river
through seasonal studies (Soliman, 2006), or because dilution factor or unstable of
water levels in river under study (Kalff, 2002).
High concentration of heavy metals were showed in particulate phase of water.
The highest concentration of Fe is 632.41 µg/g dry weight was observed in Spring
2005 (Table-1). These concentrations increased in particulate phase compare to
dissolved phase of heavy metals due to the increase in level of suspended matter by
erosion process or soil drift from near land and rise of river slop (Rainbow, 2007), and
tendency of heavy metals to adsorption on particulate matter surface in water column
(Demina et al., 2009).
Sediment analysis showed that the highest concentration of heavy metals was
found in Euphrates river in period of study. The amount of heavy metals of (Cd, Co,
Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in exchangeable phase of sediment ranged (5.076.75), (4-4.11), (0.14-0.20), (6.97-7.46), (300.50-340.9), (17.25-17.50), (0.088-0.099),
(0.241-0.273) and (29.99-31.20) µg/g dry weight respectively, but in residual phase
the study showed high similarity in metals concentration with values of these metals
in exchangeable phase of sediments (Table-1), of what to signal of similarity in
pollution source through different time sequence (Barsytelovejoy, 1999), of what
make the sediments as potential source to heavy metals pollution and transplantation
of this metals through food chain to aquatic system (Ardalan et al., 2006).
The increase of heavy metals concentration in sediments may be correlated with
sediment count of organic matters and these concentrations were negative correlation
with sediment grain size. These result agreed with study of (Salman, 2006) at refer to
small grain size and tendency to (silt-clay) of Euphrates river sediments addition to
exposure this sediment to discharged of industrial and domestic waste and mining
(Chindah et al., 2004). Higher concentration of heavy metals in sediment than in
water was observed in different studies and the major depository of metals in some
cases, holding more than 99 percent of total amount of a metal present in the aquatic
system (Netpae & Phalaraksh, 2009).
In soft tissues of fresh water clam under study mean concentrations of metals
followed the sequence Fe<Zn<Mn<Cu<Cd<Co<Pb<Cr<Ni and the yearly average of
this heavy metals at (3.30), (26.96), (1.36), (47.15), (1964), (117.35), (0.64), (1.71)
and (200.11) µg/g dry weight respectively. The rise of metals concentration in clam
may be return to ability of bioaccumulation in soft tissues in high levels (Hedouin et
al., 2007). In this field (Barsiene et al., 2002) referred to the bivalve have ability of
metal accumulation in 1000/100 concentration in water the results of this study
showed that the bivalves from Euphrates river follow normal patterns of heavy metal
content variability, related to differences between stations and seasons.
886
Journal of Babylon University/Pure and Applied Sciences/ No.(3)/ Vol.(19): 2011
The metal concentrations measured reflect a clear influence of anthropogenic
activities, additionally, the effective exposure of organisms to different metals may be
influenced by either changes in metal speciation or relative distribution of metals
between particles of different sizes and densities (Turkmen et al., 2005). The strong
relationship showed between metal concentration in clam soft tissues and
concentrations of these in particulate phase of water this due to the filter-feeding and
detritus feeding of this organisms and the organism under study may be accumulate
the different pollutants more than sediments and water (Madkour, 2005).
The results of the study to show clear variance in concentration of heavy metals
through study seasons may be due to effective of metals availability in aquatic
organisms by different environmental factors such as pH, water hardness and amount
and compound of particulate matters (Phillips, 1977), or may be as result of biological
action change of this organisms and effected of amount of food and productivity by
photoperiods (Chindah et al., 2004; Gbaruko & Friday, 2007).
From statistical analysis the study showed significant variation (P<0.05) in
metals concentration in water, sediment and clam between seasons, and showed some
correlation between heavy metals under study such as dissolved Cd and Cd in clam
soft tissue (P<0.05, r=-0.98), particulate Cd and residual Cd (P<0.05, r=0.99),
dissolved and particulate Co (P<0.05, r=0.95), particulate, residual Mn, dissolved Mn
and Mn in clam (P<0.05, r=-0.45, r=-0.98) respectively, but not found any correlation
between other heavy metals.
The present study deals with determination the mechanism of heavy metals
accumulation through the system water-sediment-clam, than to observe the most
metal under study to seize the same place in metals sequence in water, sediments and
soft tissue of clam to confirm the interaction between the compound of this system,
these result confirm in many studies (Soliman, 2006; Ardalan et al., 2006; Madkour,
2005; Barsytelovejoy, 1999; Turkmen, et al., 2005; Shanmugam et al., 2007; Netpae
& Phalaraksh, 2009; Ohimain et al., 2008; Gabr & Gab-Alla, 2008; Liu et al., 2007;
and Gbaruko & Friday, 2007).
The pattern of variation of heavy metal accumulation in whole soft tissues of the
clam appears to be influenced largely by the reproductive stage of the organism
(Amisah et al., 2009).
From the results (Table-2) become clear the different heavy metals under study
Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were accumulated in soft tissue of fresh water
clam P.euphraticus by bioaccumulation factor (BAF) as (16.81, 20.73, 12.36, 12.44,
15.79, 15.06, 12.8, 12.04, & 15.69) than concentration in water respectively. This
results provide good evidence of metals accumulation in aquatic organisms more than
water and sediment that help use this organisms as bioindicators and as a good
environmental tools to study of aquatic pollution (Hedouin et al., 2007).
The study of bioaccumulation factor (BAF) in aquatic organism's tissues useful
to explain the best organism have the ability of heavy metals bioaccumulation in
environment and help to used this organisms as clam in environmental monitoring
programs (Rainbow, 2007). Determination of harmful and toxic substances in water,
sediments and biota, gives direct information on the significance of pollution in the
aquatic environment (Gbaruk & Friday, 2007).
887
Table (1): Concentrations of heavy metals in water, sediments and soft tissues of
fresh water clam P.euphraticus
(µg/L to dissolved phase, µg/g to particulate phase and sediment and clam).
Element concentration in
water
Element concentration
sediment(ug\g)
Dissolved
2.50
1.55
1.70
2.65
0.90
1.91
1.35
0.94
0.05
0.15
0.11
0.13
3.73
4.52
3.99
2.90
144.75
189.60
Particulate
10.90
11.00
10.40
11.25
8.70
9.10
8.90
9.07
0.40
N.D
0.80
0.18
14.90
15.01
14.89
15.11
632.41
613.06
Exchangeable
5.10
6.75
5.07
5.18
4.01
4.09
4.05
4.11
0.14
0.17
0.20
0.19
7.30
7.46
6.97
7.09
300.50
332.27
Residual
5.35
6.97
5.47
5.31
4.60
4.54
4.78
4.89
0.29
0.47
0.25
0.41
7.90
7.85
7.20
7.89
354.60
378.65
93.32
619.43
340.19
360.30
69.54
625.11
321.18
381.09
Autumn 2005
8.90
10.61
6.70
4.98
0.02
0.06
0.04
0.05
0.10
0.18
0.14
34.85
35.09
36.07
36.19
0.182
0.198
0.201
0.220
0.550
0.540
0.561
17.50
17.33
17.25
17.50
0.095
0.091
0.099
0.099
0.264
0.241
0.273
17.90
17.89
17.46
17.57
0.098
0.10
0.12
0.12
0.271
0.2 82
0.292
Total
10.45
13.72
10.54
10.49
8.66
8.63
8.83
9.00
0.43
0.64
0.45
0.60
15.20
15.30
14.17
14.98
655.1
710.9
2
700.4
9
702.2
7
35.40
35.22
34.71
35.07
0.193
0.191
0.219
0.219
0.535
0.523
0.565
Winter 2006
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
0.142
15.06
17.91
10.15
8.59
0.601
59.91
61.22
58.80
63.30
0.256
30.07
29.99
31.20
30.11
0.298
31.40
32.09
32.29
34.06
0.565
61.47
62.08
63.49
64.17
Element
Seasons
Cd
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
Spring 2005
Co
Cr
Cu
Fe
Summer 2005
Autumn 2005
Winter 2006
Mn
Ni
Pb
Zn
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
Spring 2005
Summer 2005
Autumn 2005
Winter 2006
Spring 2005
Summer 2005
888
in
Element
concentration
in clam(ug\g)
35.29
35.32
35.31
35.29
26.98
26.97
26.96
26.96
1.38
1.33
1.33
1.38
47.16
47.14
47.11
47.10
1937.9
1942.6
1956.1
2006.4
117.20
117.69
118.13
117.30
0.63
0.65
0.66
0.66
1.70
1.71
1.70
1.70
200.04
199.96
200.14
200.09
Journal of Babylon University/Pure and Applied Sciences/ No.(3)/ Vol.(19): 2011
Table (2): Yearly average of heavy metals concentration in water, sediments and
clam soft tissues P.euphraticus and Bioaccumulation factor (BAF) in clam tissue.
( Dissolved= ug\l ; particulate ; sediment and clam =mg\g)
Element
in water
concentration
Element concentration in
sediment
Element
Total
Element
concentration
in clam
BAF
Dissolved
Particulate
Exchangeable
Residual
Cd
2.1
10.89
5.53
5.78
5.66
35.30
16.18
Co
1.3
8.94
4.07
4.70
4.38
26.96
20.73
Cr
0.11
0.13
0.18
0.36
0.27
1.36
12.36
Cu
3.79
14.98
7.21
7.54
7.38
47.15
12.44
Fe
124.30
622.50
323.53
368.66
346.10
1963
15.79
Mn
7.79
35.55
17.39
17.71
17.55
117.35
15.06
Ni
0.05
0.199
0.093
0.10
0.097
0.64
12.80
Pb
0.142
0.56
0.26
0.29
0.28
1.71
12.04
Zn
12.75
60.81
30.34
32.46
31.4
200.11
15.69
889
Cd
Co
40
30
35
25
25
20
Cd
15
Concentration
Concentration
30
10
20
15
Co
10
5
5
0
0
0
0
1
2
3
4
5
1
2
3
4
5
6
6
1-Dissolved Co 2-Particulat Co 3-Exchangeable Co 4Residual Co 5-Co in Clam
1-Dissolved Cd 2-particulate Cd 3-Exchangeable Cd 4Residual Cd 5-Cd in Clam
Cr
Cu
50
1.6
45
1.4
35
1
0.8
Cr
0.6
Concentration
Concentration
40
1.2
30
25
20
0.4
15
0.2
10
0
Cu
5
0
1
2
3
4
5
6
0
0
1-Dissolved Cr 2-Particulat Cr 3Exchangable Cr 4-Residual Cr 5-Cr in Clam
1
2
3
4
5
6
1-Dissolv ed Cu 2- Particulate Cu 3-Exchangeable Cu4Residual Cu 5-Cu in Clam
Fig.(1): Yearly average of(Cd ,Co, Cr, Cu) concentrations in water; sediment,; and clam
soft tissues P. euphraticus.
890
Journal of Babylon University/Pure and Applied Sciences/ No.(3)/ Vol.(19): 2011
Fe
Mn
2500
140
120
2000
Concentration
100
concentration
1500
Fe
1000
80
Mn
60
40
500
20
0
0
0
0
1
2
3
4
5
6
1
2
3
4
5
6
1-Dissolv ed Mn 2-Particulat Mn 3-Exchangable Mn 4-
1- Dissolv ed Fe 2-Particulat Fe 3- Exchangabel Fe 4-
Residual Mn 5- Mn in Clam
Residual Fe 5- Fe in clam
Pb
Ni
1.8
0.7
1.6
0.6
1.4
1.2
Concentration
Concentration
0.5
0.4
Ni
0.3
1
Pb
0.8
0.6
0.2
0.4
0.1
0.2
0
0
1
2
3
4
5
0
6
0
1-Dissolv ed Ni 2-Particulat Ni 3-Exchangaeble 4-
1
2
3
4
5
6
1-Dissolv ed Pb 2-Particulat Pb 3- Exchangable Pb 4-
Residual Ni 5-Ni in Clam
Residual Pb 5-Pb inClam
Zn
250
concentration
200
150
Zn
100
50
0
0
2
4
6
1-Dis s olve d Zn 2-Particulat Zn 3Exchangable 4-Ris idual 5- Zn in Clam
Fig.(2): Yearly average of (Fe ; Mn ; Ni ; Pb ; and Zn ) Concentrations in water ,
sediment and Clam soft tissue P. euphraticus.
891
References
Amisah, S.; Adjei-Boateng, D.; Obirikorang, K.A. & Quagrainie (2009). Effects of
clam size on heavy metal accumulation in whole soft tissues of Galatea paradoxa
(Born, 1778) from the Volta estuary. Ghana. Inter. J. Fisher. Aquacul., 1 (2):
014-021.
Ardalan, A.A; Khoshkhoo, Z.; Rabbani, M. & Moini, S. (2006). Comparative study
for heavy metals concentration (Zn, Cu, Pb, Cd, and Hg) in water, sediments and
soft tissue of Anzali lagoon Anodont (Anodonta cygnea) sampled in two seasons,
Autumn and Spring (2004-2005). Pajouhesh & Sazandegi, No. 73: 103-113.
Barsytelovejoy, D. (1999). Heavy metal concentrations in water, sediments and
Mollusks tissues. Acta Zoologica Lituanica, Hydrobiologia, 9 (2): 12-20.
Chindah, A.C.; Braide, A.S. & Sibeudu, O.C. (2004). Distribution of hydrocarbons
and heavy metals in sediment and acrustacean (Shrimps-Penaeus notialis) from
the Bonny/New Calabar river Estuary, Niger Delta. Ajeam-Regee, 9: 1-17.
Christopher, E.A.; Vincent, O.; Grace, I.; Rebecca, E. & Joseph, E. (2009).
Distribution of heavy metals in bones, gills, livers and muscles of (Tilapia)
oreochromis niloticus from Henshaw Town Beach market in Calabar Nigeria.
Pak. J. Nutr., 8 (8): 1209-1211.
Demina, L.L.; Galkin, S.V. & Shumilin, E.N. (2009). Bioaccumulation of some trace
elements in the biota of hydrothermal fields of the Guaymas Basin (Gulf of
California). Boletin De LA Sociaeded Geologica Mexicana, 61 (1): 31-45.
Edem, C.A.; Akpan, .B. & Dosunmu, M.I. (2008). A comparative assessment of
heavy metals and hydrocarbon accumulation in Sphyrena afra, Orechromis
niloticus and lops lacerta from Anantigha Beach market in Calabar-Nigeria. Afr.
J. Environ. Pollut. & Health, 6: 61-64.
Etim, L.; Akpan, E.R.; Muller, P. (1991). Temporal trends in heavy metal
concentrations in the clam E.radiata (Bivalvia: Tellinacea Donacidae) from the
cross river, Nigeria. Rev. Hydrobiol. Trop., 24 (4): 327-333.
Gabr, H.R. & Gab-Alla, A.A, (2008). Effect of transplantation on heavy metal
concentrations in commercial clams of lake Timsah, Suez canal, Egypt.
Oceanologia, 50 (1): 83-93.
Gbaruko, B.C. & Friday, O.V. (2007). Bioaccumulation of heavy metals in some
fauna and flora. Int. J. Environ. Sci. Tech., 4 (2): 197-202.
Hedouim, L.; Pringault, O.; Metian, M.; Bustamante, P. & Warnau, M. (2007). Nickel
bioaccumulation in Bivalves from the New Caledonia Lagoon: Sea water and
food Exposure. Chemospher, 66: 1449-1457.
Kalff, J. (2002). Limnology, Inland water Ecosystem prentice Hall, upper Saddle
River, New Jersey, 7458. pp. 592.
Liu, C.W.; ;Liang, C.P.; Lin, K.H.; Jang, C.S.; Wang, S.W.; Huang, Y.K. & Hsueh,
Y.M. (2007). Bioaccumulation of arsenic compounds in aquaculture clams
(Meretrix lusoria) and assessment of potential carcinogenic risks to human health
by ingestion. Chemosphere (2007) (in press) 2007. 04.038.
Madkour, H.A. (2005). Distribution and relationships of heavy metals in the Giant
clam (Tridacna maxima) and associated sediments from different sites in the
Egyptian Red Sea coast. Egyptian J. of Aquatic Research, 31 (2): 45-50.
Netpae, T. & Phalaraksh, C. (2009). Water quality and heavy metal monitoring in
water, sediments, and tissues of Corbicula sp. From Bung Boraphet Reservoir,
Thailand. Chiang Mai. J. Sci., 36 (3): 395-402.
892
Journal of Babylon University/Pure and Applied Sciences/ No.(3)/ Vol.(19): 2011
Ohimain, E.; Jonathan, G. & Abah, S.O. (2008). Variations in heavy metal
concentrations following the dredging of an oil well access canal in the Niger
Delta. Advan. Biol. Res., 2 (5-6): 97-103.
Otchere, F.A. (2003). Heavy metals concentrations and burden in the bivalves
(Anadara (Senilia) senilis, Grassostrea tulipa and Perna perna) from lagoons in
Ghana: Model to describe mechanism of accumulation/excretion. Afr. J.
Biotechnol., 2 (9): 280-287.
Philips, D.J.H. (1977). The use of biological indicator organisms to monitor trace
metal pollution in marine and Estuarine Environments A review.
Environ.Pollut.,13:281-317.
Rainbow, P.S. (2002). Trace metal concentrations in aquatic invertebrates: Why and
so What?. Environ. Pollut., 120: 497-507.
Rainbow, P.S. (2007). Trace metal bioaccumulation: Models, metabolic availability
and toxicity. Environment International, 33: 576-582.
Salman, J.M. (2006). Environmental study of some possible pollutants in Euphrates
river between Hindia dam and Kufa-Iraq. Ph.D.Thesis. College of Science/
Babylon university, Iraq.
Shanmugam, A.; Palpandi, C. & Kesavan, K. (2007). Bioaccumulation of some trace
metals (Mg, Fe, Zn, Cu) from Bowl Cymbium melo (Solander, 1786). (A marine
Neogastropod). Res. J. Environ. Sci., 1 (4): 191-195.
Soliman, Z.I. (2006). A study of heavy metals pollution in some aquatic organisms in
Suez cannal in port-said Harbour. J. Applied Sci. Res., 2 (10): 657-663.
Turkmen, A. (2003). Iskenderun Korfezinde Deniz suyu, Askidaki Kati madde,
sediment ve Dikenli Tas Istiridyesinde (Spondylus spinosus Schreibers, 1793)
Olusan Agir metal Birikimi uzerine Arastirma, Ph. D. Thesis, Erzurum: Ataurk
Univ. Fen. Bilimleri Enstitusu.;
Turkmen, A.; Turkmen, M. & Tepe, Y. (2005). Biomonitoring o heavy metals from
Iskenderun Bay using two Bivalve species Chama pacifica Broderip, 1834 &
Ostrea stentina Payraudeau, 1826. Turk. J. Fish. Aquat. Sci., 5: 107-111.
Wang, W.X. (2002). Interactions of trace metals and different marine food chains.
Mar. Ecol. Prog. Ser., 243: 295-309.
893