ENVIRONMENTAL MONITORING STUDY USING BIVALVES AS BIOINDICATOR FOR
POLLUTION CONTROL AND SUSTAINABLE DEVELOPMENT IN THE CENTRALCOASTAL REGION OF VIETNAM
1. INTRODUCTION
There have been studies on the use of organism species as bioindicators for environmental
quality monitoring and pollution control. Depending on the physic- chemical properties andenvironmental of pollutants as well as biological characteristics, accumulate ability of theorganism can be select as environmental bio- indicators accordingly.
Pollutants affecting marine ecosystems include a wide range of synthetic organic chemicals,(Substances of particular concern are PCBs, pesticides, dioxin and some industrial solvents);
diverse heavy metals and alloys, but also, alternatively, toxins and pathogenic species;
pharmaceuticals.v.v. All these pollutants reach the ocean floor through coastal region, whichconnects pollutions to the marine ecosystem. Though coastal region are highly productive,
dynamic and much diversified regions, the entry of these chemicals in the biotic system ismuch easier. From the marine biotic communities the bottom dwelling mollusks have atremendous capacity of bioaccumulation. Since the coasts are more prone to theaccumulation of all toxic chemicals and there is a higher chance of accumulation in the bodyof mollusks.
Bivalves species are good bioindicators considering their ability to filter large volumes of sea
water and thus highly to accumulate trace contaminants. Bivalves have been particularly
used as bioindicators in many countries for marine pollution monitoring. These species aremollusks, lives at bottom depths, directly strongly affected by tides and coastal waters. These
animals are adaptable or very sensitive to the environment. These species are often highly
susceptible to physiological and biochemical conditions.
Over the last three decades, Vietnam has undergone rapid economic development.
Recently, human health concerns related to the occurrence of pollutants such as POPs andheavy metals in aquatic environments in Vietnam have been greatly increasing. In recent
years, there are industry and tourism that has strongly developed in the Central region
Vietnam. In coastal marine areas of the Central region Vietnam is still receiving the large
discharges sources containing pollutants from the mainland to the sea. To manage
contaminated coastal sites and prevent adverse effects on human health, the Vietnamese
government has undertaken a number of monitoring program. However, very few extensive
monitoring studies carried out in the coastal areas of the Central Vietnam.
2. AIMS-

Determination concentration PCBs and heavy metals in sediment and bivalvesorganisms in coastal areas in Quy Nhon, Binh Dinh province-

Determination the bioaccumulation of POPs/PCBs and heavy metal for each bivalvesorganisms-

Assessment the current contamination status by heavy metals and PCBs/POPs in Quy
Nhon, central coastal region of Vietnam-

Based on the findings of this study can be proposed the monitoring measurement using
bivalve’s species in order to pollution control and coastal marine environmental
management of Vietnam.

3. PROCEDURES

3.1. SAMPLING-Location: The coast long of Quy Nhon is 72 km. Quy Nhon citis located13.78 latitude and 109.22 longitude and it is situated at elevation 7 meters
above sea level. (Figure 1).
-Collection: Sediment samples and 3 bivalves species samples were collected in Augustand September 2019 from tens location in coastal areas Quy Nhon belong to Binh Dinhprovince, central Vietnam (Figure.1).
+ Sediment collection: The sediment samples of the top 20cm surface centimeter werecollected with a polyethylene spool or Ekman grab, then placed in a plastic bag, whichwere stored in an ice box at 40C, to be transported to the laboratory. There sediment
samples were dried at room temperature, and then were sieved through a nylon meshto obtain particles smaller than 0.2mm in diameter for determination of heavy metal
concentration. For each sediment sample, 3-5Ige gram was taken for heavy metal andPOPs/PCBs analysis.
+ Bivalves collection: About 10-15 numbers of the same sizes of each bivalve species(Crassostrea rivularis, Chlamys nobilis, and Anadara grasnosa) were picked by hand fromthen locations and then put in ice box at 40C to be transported to the laboratory. The
tissues were separated by a plastic knife and dried at 110oC during two days to constant
dry weight. These dried tissues were then stored in a polyethylene bag to be kept
laboratory condition for the determination of heavy metals and PCBs concentrations.

Figure 1. Map of sampling location in Quy Nhon coastal area belong to Binh Dinhprovince, central of Vietnam
Table 1: Characteristic description of sampling location in Quy Nhon coastal area
Site markLocation

Coordinates(Longitude-latitude)

Characteristics description

1

VT1

Quy Nhon Beach

13°45'06.7"N
109°12'60.0"E

Beach area

2

VT2

Port of Hai Doan 48

13°46'07.9"N

It is a big harbor with109°15'05.2"E3

VT3

Hà Thanh River mouth

13°47'02.3"N
109°13'34.7"E

4VT4Nhon Hoi Bridge

13°48'40.0"N
109°16'39.7"E5VT5Thị Nại lagoon(outside of lagoon)

13°46'00.3"N
109°17'33.3"E

6

VT6Nhơn Hội area

13°53'15.0"N
109°16'58.0"E

7VT7Nhon Ly coastal area

8

VT8

9

VT9

Ky co coastal area

10

VT10

Thị Nại lagoon(inside of lagoon )many boats and ships fortrade
It is the location ofconcentrated aquaculture
activities
There are civil transport
activities
The location ofconcentrated aquaculture
activities
Location near the area isbuilding factories locatedin Nhon Hoi economic zone
Human activities: people
living, trading…
Port area, many boats,ships anchored

13°52'39.4"N
109°17'44.8"E
13°53'19.0"N
109°17'44.8"E
13°51'02.6"N
109°17'32.4"E
13°49'42.5"N
109°15'28.7"ENhơn Lý port bridge

Beach area
Location is under the
middle of Thi Nai bridge

3.2. ANALYTICAL METHODS
3.2.1. For Heavy metals: Concentration of Hg, Pb, Cd, Cu, Cr, were analyzed in 10
sediments and 30 bivalves samples using ICP-MS. The methods used for sample
preparation, digestion, and quantificational analysis were established, generating
satisfactory analytical precisions which represented by relative standard deviations(RSD) ranging and recoveries showing in Table 2.
Table 2. Estimation of the repeatability of the heavy metals analysis by the Relative
standard deviations (%) and recovery (%)
RSD (%)
Hg

Pb

Cd

Cu

Zn

Sediment

0,27

0,900

0,070

1,63

0.85

Bivalve organism

0,42

0,16

0,0102

1,08

0,50

Recovery (%)
Sediment

95-101 92-105

93-10599-10988-102

Bivalve organism 89-102 91-110

95-11097-10990-1053.2.2. For PCBs and organochlorin pesticides
PCBs in the dried samples were analyzed using GC-MS, after extraction withhexane/acetone (1:1 v/v) and clean-up with gel-permeation chromatography andactivated silica-gel.
3.3. Data analysisa) Concentration of heavy metals in sedimentCs =(mg/kg dry sediment)

In which: Cs: heavy metals contents (mg/kg dry sediment).

Cđo: heavy metals concentraion measured (mg/L).
Vđm: sample volume; m: sample weight (g); K: dry coefficient of sedimentb) Concentration of heavy metals in bivalves species
Ct =(mg/kg dry organism)

In which: Ct: content of heavy metals (mg/kg) in bivalve species.
Cđo: metal concentration measured (mg/l).
Vđm: volume of solution measured on (ml). m: sample weight (g)c) BSAF (Biota-sediment Accumulation Factor)

BSAF

Ct / f L
Cs / f OC

In which: Cs: content of heavy metals (mg/kg) in sediment-Ct is the concentration of heavy metal in the tissue of bivalves species (µg /g of dried meat tissue).
- fL: lipid content in the tissue of living organisms (%).
- foc: content of organic carbon in sediments (%)d) Igeo (Geological accumulation Index)
Igeo=Log2 Cx/1,5 Bx
In which: Cx: content of heavy metals (mg/kg) in sediment
Bx : background concentration value of metal x in the Earth's crust(Bx value according to Turekian K. K., and Wedepohl K. H. (1961):
4. RESULTS AND DISCUSSION
4.1. Concentration of heavy metals in sediment
Concentration of Hg, Pb, Cd, Cu, Zn were found in almost sediment
samples and collecting location. The concentrations of heavy metals were
showed a variation between the metals and between sites. Metal concentrationsin the sediments ranked in the following order: zinc > copper > lead >cadmium> mercury. Elevated concentrations of heavy metals were showed highlevels from 5 locations, such as VT1, VT2, VT3, VT4 and VT5, as show in Table
3 and Fig. 2. With the described characteristics of each sampling location (Table1), the VT1 location is the stationed area of naval army units 48, VT 2 and VT4
are the big ports, VT3 and VT5 farming and aquaculture areas. . The area isrich in the cultivation, manufacturing, transportation and tourism activities of
Quy Nhon City....

Table 3: Concentration of Hg, Pb, Cd, Cu, Zn in sediment (mg/kg dry weight)
Site
mark

Hg

Pb

Cd

Cu

Zn

0.072

4.109

3.23

20.91

41.62

0.083

6.225

2.34

41.62

165.04

0.039

3.694

4.15

163.04

58.37

0.016

0.756

1.66

58.37

51.20

N.D.

4.651

1.78

51.20

39.77

0.040

2.321

1.54

39.71

51.42

0.014

0.754

2.03

51.42

57.91

VT8

0.012

1.173

2.35

57.91

23.99

VT9

0.029

2.023

1.28

23.99

36.35

VT10

0.032

3.028

1.97

28.65

41.62

VT1
VT2
VT3
VT4
VT5
VT6
VT7

Fig.2. Concentration of heavy metals in sediment collected at Quy Nhon coastal area (a) Hg, b)
Cu and Zn, c) Pb and Cd
Table 4. Assessment of environment status of heavy metal based on Sediment Quality
Guideline (mg/kg dr.wt)
Quy Nhon coastal area (n=10)

Hg

Pb

Cu

Cd

Zn

Minimum

0.012

0.754

20.91

1.28

23.35

Maximum

0.083

6.225

163.044.15

165.04

Threshold effect level (TEL)a

0.70

112

108

42

271

Probable Effect Level (PEL)b

0.70

250

110

10

110

0.15

112

108

4,2

160

0.13

31

16

0,6

26

Threshold effect level (TEL)bb

Effect range – low (ERL)Note:a QCVN 43/2012/BTNMT National Regulation for Sediment Quality of Vietnam
bSediment Quality Guideline of CanadaIn order to assess the current environmental heavy metal pollution in sediments, themethod of SQGs (Sediment Quality Guideline and Igeo values were used. The result of thecontent of some heavy metals in sediments in Quy Nhon coastal area is compared with the
National Technical Regulation on Sediment Quality – QCVN 43: 2012/BTNMT and
Guideline on Sediment Quality of Ontario, Canada (1993) - the prescribed values to protect
aquatic systems to assess the level of pollution and accumulation of heavy metals in the
study area (Table 4)
The results of Hg content in sediment samples ranged from 0.012 mg/kg (at VT8 location)
to 0.083 mg/kg dry wt (at VT4 location). Concentration of Hg in all samples did not exceed
the limit value of sediments (0.7 mg/kg dr wt) is regulated in QCVN 43: 2012/BTNMT
sediment quality standards.
The results of Pb content in sediment samples ranged from 0.754mg/ kg (at VT8) to 6.225
mg/kg dry weight (at VT2 location). The content of Pb in all samples are within the limits of
QCVN 43:2012/BTNMT National Technical Sediment Quality Standards as well as inOntario - Canada sedimentary quality guideline.
The metal content results in Table 2 also show that Cu content in sediment samples ranges
from 20.91 to 163.04 mg/ kg dry weight. The content Cu of almost location were foundwithin the limits of QCVN 43:2012/BTNMT, exception of VT3 location (163.04 mg/kg dr wt)
However, according to the Ontario - Canada sediment quality guidelines, Cu concentrationin sediment of all location were higher the Effect low Level (LEL).(16mg/kg dr wt).
With the content range from 23.99 to 165.04 mg/kg dry weight, concentration of Zn in
sediment samples at all location do not exceed the limit value specified in QCVN 43: 2012 /BTNMT. However, according to the Ontario - Canada sediment quality guidelines, Cu
concentration in sediment of all location were higher the Effect low Level (LEL).(23 mg/kg
dr wt).
Zinc has a similar trend to copper with location differences: the highest concentrations inthe surface sediment occur in the VT2 and VT3 as Cu:163,04 mg/kg dr wt and Zn:165,04
mg/kg dr.wt, respectively. These location are closed the big harbour and concentrated
aquaculture. The sampling period in August and September is the time when the most
exciting activities of the year in Quy Nhon area. In this study, the sampling period in
August and September is the time when the most exciting activities of the year in Quy
Nhon area. Because the weather is good at the moment, no rain, no floods or storms, so
crowded tourists, ports with busy boats and aquaculture areas are also very developed.
High concentration of Zn and Cu can showed high sign of anthropogenic contamination
sources. Sometime Zn and Cu in sediment are from natural source as their natural presence inthe lithosphere.
4.2. Concentration of heavy metals in sediment (not finished yet and to be continued)
Table 5. Concentration of Hg, Pb, Cd, in 3 bivalve species (mg/kg dry weight)

Crassostrea rivularis

Chlamys nobilis

Hg

Pb

Cd

Hg

Pb

VT2

0.098
N.D

2.941
3.323

1,26
1,68

0.205
0.469

VT3

0.018

3.575

1,45

VT4

0.108

3.126

VT5

N.D

VT6

0.002

VT1

Cd

Anadara granosa
Hg

Pb

1.499
4.463

0.028
0.025

11.382
5.134

0.029

0.249

0.039

8.954

1,48

0.124

4.870

0.015

5.164

3.541

1,28

0.059

3.615

0.080

3.559

3.462

0,16

N.D

1.474

0.019

7.711

Cd

VT7

0.012

1.270

2,34

0.029

1.137

0.006

4.683

VT8

0.032

3.426

1,45

0.024

1.258

0.038

6.362

VT9

0.024

3.157

1,03

0.035

1.984

0.085

4.194

VT10

0.038

3.146

1,97

0.127

2.035

0.073

8.654

Table 6. Concentration of Cu, Zn in 3 bivalve species (mg/kg dry weight)
S
TT

Crassostrea
rivularis

Chlamys nobilis)

Cu

Zn

Cu

Zn

Cu

Zn

Site

Anadara granosa

1

VT1

66.71

602.61

4.64

86.0081.32

110.088

2

VT2

65.80

568.5815.16

77.44364.80

69.347

3

VT3

75.24

573.9718.17

56.91261.68

89.378

4

VT4

60.03

685.6319.67

58.25489.31

111.955

5

VT5

59.73

804.5017.92

55.90080.5480.367

6

VT6

76.82

757.4215.87

94.049-83.663

7

VT7

49.53

486.2013.84

69.94575.10

115.570

8

VT8

59.73

581.1919.49

73.065-102.009

9

VT9

55.08

548.7020.91

63.854

10

VT10

48.37

593.00

18.02

53.3

-

83.4

117.51

101.5

4.3. Concentration of PCBs in bivalve species (7 samples)
Table 6. Concentration of PCBs (ng/g wet weigh)Sample1

Sample2

Sample3

Sample4

Sample5

Sample6

Sample7

Total PCBs(61
PCB
congeners)

7.63

8.18

9.59

8.69

0.05

0.03

0.02

Total
indicator
PCBs
(6
PCB
congeners)

2.94

3.19

3.77

3.34

0.05

0.03

0.02

Total dioxin
like-PCBs(12
PCBcongeners)

0.28

0.27

0.38

0.32

0.00

0.00

0.00

Total

0.008

0.008

0.011

0.010

0.000

0.000

TEQ

0.000

dioxinlike-PCBs(12
PCBcongeners

Table 7. Concentration of PCBs (ng/g lipid wet weigh)Sample1

Sample2

Sample3

Sample4

Sample5

Sample6

Sample7

Total PCBs (61PCB
congeners)

91.69

84.70

77.36

211.54

1.36

0.81

0.71

Total indicator
PCBs (6 PCB
congeners)

35.29

33.00

30.46

81.34

1.36

0.81

0.71

Total
dioxinlike-PCBs (12PCBcongeners)

3.33

2.83

3.03

7.79

0.000

0.000

0.000

Total
TEQ
dioxinlike-PCBs (12PCB congeners

0.000100.00008

0.00009

0.000230.00000

0.00000

0.00000

5. RECENT PUBLICATION

1. Le Thu Thuy, Le Thi Hai Le, Nguyen thi Thuc Anh, Luong Ngan Ha, Nguyen Thanh
Thao (2018). Concentration of some heavy metals (Cd, Pb, Zn) in bivalve species in Quy
Nhon coastal area, Binh Dinh province. Journal of Analytical Science (ISSN-0868-3234),

T-23, Vol 4A, 214-2019

2. Le Thi Hai Le, Tran Hong Con, Le Thu Thuy (2018). The retention and transformationof some heavy metals in urban dredged sludge. Journal of Analytical Science(ISSN-0868-3234), T-23, Vol 4A, 169-176
3. Le Xuan Sinh, Le Thi Hai Le, Mai Huong (2019) Bioaccumulation of mercury in clams(meretrix lyrata) cultured at Bach Dang estuary: A recommendation for safely daily
dosage consumption of Clam in Vietnam (2019). The 20th International Conference on
Pollutant Responses in Marine Organisms (PRIMO 20) in May 19-22, 2019, Charleston,South Caroline, USA. P59

4. Le Thi Hai Le, Le Thu Thuy, Do Le Chinh (2019). Concentration of Hg, Pb and Cd in ovsters(Crassostrea rivularis) and surface sediments in coastal areas of Binh Dinh province.
Journal of Analytical Science (ISSN-0868-3234), T-24, Vol 4A, 132-13810