chapter 4

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Chapter 4: WATER ENVIRONMENT
CHAPTER 4
WATER ENVIRONMENT
63
NATIONAL STATE OF ENVIRONMENT 2010
64
V
ietnam has a large river and canal network including 13 large river systems which cover more than
10,000 sq.km. Surface water resources are rather
plentiful, making up about 2% of the total flow of all
rivers in the world. The annual total flow of the Mekong river is about 500 cu.km, or 59% of the total
annual flow of all rivers in the country. Total flow of the
Red river is about 126.5 cu.km (14.9%) and of Dong
Nai river is 36.3 cu.km (4.3%). Ma, Ca and Thu Bon
rivers have the same total flow, about 20 cu.km each
(2.3 - 2.6%). Ky Cung, Thai Binh and Ba rivers also
have the same total flow, approximately 9 cu.km each
(1%). The remaining rivers have a total flow of about
94.5 cu.km (11.1%) (Source: Department of Water
Resources Management). These precious resources
make an important contribution to the national socioeconomic development. However, the surface water in
Vietnam is facing numerous challenges, particularly
water exhaustion and pollution on an extensive scale.
According to statistics, total reserves of surface water in Vietnam are more than 830-840 billion cu.m,
more than 60% of it generated from foreign countries (Department of Water Resources Management,
2010). Water resources in rivers, lakes and reservoirs
throughout the country are seriously exhausted. Major reasons include over exploitation and the impact
of climate change.
International organisations of Water Resources have
recommended that the sustainable exploitation level is
less than 30% of the total flow. In reality, most of central
and Central Highlands provinces have been exploited
to more than 50% of the total river flow. Particularly in
Ninh Thuan provinces, 70-80% of the total river flow is
exploited. The exploitation of water resources has seriously exhausted the flow and quality of water in 7 to 8
major river basins in Vietnam including the Red, Thai
Binh and Dong Nai river basins.
65
NATIONAL STATE OF ENVIRONMENT 2010
In addition, because Vietnam lies in the lower section of major rivers, over 60% of its total river flow
depends on the flow in the upper sections which are
outside the country’s boundaries. Recently, countries
lying in the upper sections have built large-scale
hydro electric power works which have further exhausted the water flow into Vietnam and seriously affected the areas which are very dependent on these
water sources. 95% of the water flow of Cuu Long
(Mekong) river in Vietnam depends on international
water sources while its rate of reserve is the smallest
of all rivers in the country. At the same time, this region is the largest water user, has the highest population density and the second largest number of poor
households in the country. Similarly, 40% of water
flow in the Red and Thai Binh river basins depends on
the flow from China. Meanwhile, available water per
capita is low and population density and the number
of poor households are also high.
Impacted by climate change, the rainy season
and rainflow in Vietnam is tending to develop abnormally. As a result, drought and partial flooding
happens more regularly and on a larger scale. The
exhaustion and abnormal development of water resources illustrates that Vietnam is confronting a future
risk of water scarcity in the dry season and flooding
in the rainy season which have caused many losses in
lives and property to many regions. In recent years,
the rainy season has ended earlier and begun later
which has resulted in droughts in many areas in the
country. Particularly, the exhaustion of river water has
been clearly seen this year when deltas in the Red,
Mekong, central and Central Highlands rivers all suffered from drought.
Many industrial zones, industrial plants and urban areas have discharged untreated wastewater to
rivers and lakes which has polluted water sources
severely. As a result, water sources in many areas
cannot be used.
Socio-economic development in each river basin
is different and the contribution of pollutants to the
environment from different sectors also varies. However, the pressure of waste water mainly comes from
industrial and domestic activities (Diagram 4.1).
66
Craft villages
Medical waste
waste
Domestic
waste
3.9%
0.1%
22.0%
Cau River basin
Industrial
waste
74.0%
Chapter 4: WATER ENVIRONMENT
67
NATIONAL STATE OF ENVIRONMENT 2010
Quantity of pollutants discharged from industrial
activities
Waste water discharged from industrial establisments and industrial zones exerts the greatest pressure on the surface water environment in the country.
Each productive sector discharges specific pollutants. Waste water from mechanical and metallurgical
industries contain heavy metals, mineral oil; waste
water from the textile, dye and paper industries contain TSS, POPs and pigments; waste water from the
food industry contains considerable SS and particularly impacts on biochemical oxygen demand (BOD)
as well as discharging nutritive substances such as
nitrogen and phosphorus compounds and others.
0.39
BOD
0.09
0.08
0.18
TSS
1.48 0.33
2.39
9.41
Food and beverage prodution
Products from non-metalic minerals
Wood and forest products
Textile
23.09
23.34
Tobacco and pipe tobacco production
Leather products and leather fake products
18.98
Manufacture and repaire other transports
Chemical substance products and production
59.66
Metal production
1.79
1
0.03
1.79
Paper production and paper made products
2.5
0.01
1.14
68
5.57
0.91
2.09
0.53
0.13
1.76
Costumes production
3.48
Publishing printing and copying
0.5
Production of coke, refined petooleum products
0.01
Rubber and plastic production
Chapter 4: WATER ENVIRONMENT
The quantity of pollutants from agricultural waste water
Agriculture is the largest user of water, mainly for the
irrigation of rice and other water intensive crops. Consequently, waste water discharged by agricultural activities
into surface water makes up the largest proportion.
The irrational use of pesticides and chemical fertilizers
in agricultural production is the major cause of surface
water source pollution. On average, 20-30% of pesticides and chemical fertilizers apllied will not be retained
by plants and will be washed by rain-water and irrigation
water into surface water resources as well as accumulating in the soil and groundwater in the form of residues.
This situation is very common in agricultural production
areas, particularly the Red and Cuu Long (Mekong) river
deltas.
Quantity of pollutants from untreated urban waste water
There is an increasing demand for running water
in urban areas to meet the need of population growth
and the development of urban services. Currently,
most cities do not have a treatment system for domestic waste water. In those cities which have this system,
the rate of treated waste water is much lower than required (Box 4.1). Untreated domestic waste water from
residential and tourism areas and discharged by small
industrial and handicraft establishments are the major
cause of pollution to water sources within cities and
their outskirts.
Year
Flow of urban domestic waste water
(cu.m/day)
Everyday, Ho Chi Minh City discharges about 1.2
million cu.m of domestic waste water into the environment. According to its master plan, the city will build 9
domestic waste water treatment plants. Up to now, the
Binh Hung plant has been built and put into operation. In
phase 1, it has a capacity of 141,000 cu.m/day. Phase 2
is under construction with a capacity of 450,000 cu.m/
day. It is expected to be put into use in 2015. But even
then, the rate of treated waste water will still not reach
50% of the total.
Source: Report “Current situation of State management of environment activities in Ho Chi Minh City” by the City DONRE to the 3rd
National Environment Workshop on Nov. 17 and 18, 2010
Total quantity of waste matter (kg/day)
TSS
BOD
COD
2006
1,823,408
2,450,205
1,128,234
2,131,108
2007
1,871,912
2,515,382
1,158,246
2,187,797
2008
1,938,664
2,605,080
1,199,548
2,265,814
2009
2,032,000
2,730,500
1,257,300
2,374,900
Note: The calculation was based on WHO’s waste discharge coefficient (WHO, 1993)
Source: Center for Environmental Monitoring (CEM) - VEA, 2010
69
NATIONAL STATE OF ENVIRONMENT 2010
Organic pollution has affected many
river sections, particularly in their middle and lower sections. In some areas,
organic pollution has reached a serious
level, particularly in lower sections of
large rivers as well as small rivers, ponds,
lakes and canals within cities.
However, the pollution level depends
on the hydraulic character of the flow.
It is highest in the dry season when the
flow in rivers reduces. It also strongly depends on the degree of control of waste
discharged into the surface resources.
Currently, most waste sources released
to river basins are almost uncontrolled
which results in seriously polluted surface
water.
Variation of surface water pollution in
major rivers
In general, the quality of the surface
water in river sections which run through
urban centers, industrial zones and mining areas decreases considerably after it
receives untreated waste water from these
sources. Monitoring results showed that
the content of pollutants in major rivers
in the country has exceeded the permitted levels by 1.5 to 3 times. This situation
has continued for many years, seriously
affecting people’s lives and the surrounding environment.
Variation of pollution of surface water
within cities
Currently, most of lakes, ponds, canals
and rivers in all cities’ inner precincts and
districts are seriously polluted. The pollution has exceeded the permitted level and
many of rivers and canals have become
effectively waste water discharge canals.
Most pollutants are organic. Many lakes
in inner cities are affected by eutrophication. The surface water in these lakes be70
Tay lake
Ha Noi
Bay Mau
Kim Nguu
To Lich
lake Ha Noi river Ha Noi river Ha Noi
Tam Bạc
river
Hai Phong
Tinh Tam Nhieu Loc Tham Lương river Hue
cannal
Vam Thuat
HCM city
cannal
HCM city
Tan Hoa Lo Gom
cannal
HCM city
Chapter 4: WATER ENVIRONMENT
comes muddy and smells strongly which
spoils the cities’ environment and appearance. Monitoring results show that some
parameters have exceeded the National
Technical Regulation on surface water
quality 08:2008/BTNMT, type B2.
Cau river
Nhue - Day river
Dong Nai river
In the 3 river basins of Cau, Nhue
– Day and Dong Nai, monitoring results show that the water quality has
decreased year by year and pollution
parameters failed to meet the National
Technical Regulation on surface water
quality 08:2008/BTNMT, particularly in
regard to organic pollution.
The Nhue-Day river basin
The surface water on the Nhue-Day
river basin is badly affected by waste water from domestic, industrial, agricultural,
handicraft and aquacultural activities in
the area. Water in some river sections has
been polluted to an alarming level, particularly in the dry season. The value of BOD5,
COD and Coliform in these locations all
exceed the National Technical Regulation
on surface water quality 08:2008/BTNMT,
type A1 many times over.
Lien Mac
sewer
Phuc
La
Cu Da
Cau
Chiec
Dong
Quan
Than Nhat Tuu
sewer
sewer
Do
Kieu
Hong Phu
brigde
Nhue River
Water in the upper section (at its
confluence point with the Red river) is
almost unpolluted. In the section which
runs through Ha Dong (Phuc La area)
to the point before it receives water
from To Lich River, the water begins to
be polluted: the content of pollutants at
the measured points all exceed the National Technical Regulation on surface
water quality 08:2008/BTNMT, type
A1 many times over. Pollution sources
come from domestic waste water from
Ha Dong precinct and waste water from
local industrial plants and craft villages.
71
NATIONAL STATE OF ENVIRONMENT 2010
After receiving waste water from To Lich River,
Nhue River becomes seriously polluted. It clearly
shows that waste water from To Lich River (the main
receiver of waste water from all Hanoi’s inner precincts) is the main cause of pollution in Nhue River
(from To bridge downstream).
In the following section (from where Nhue river
receives water from To Lich river to the end (its confluence with Day river), Nhue river gradually becomes
less polluted due to the river’s self-purification. The
diversion of water from To Lich river to Yen So Lake
in the dry season to dilute the water in Nhue river
reduces the pollution level in Nhue river during this
season.
Day River
Water in Day and other river basins is less polluted than that in Nhue river and the pollution is partial.
Some sections are affected by domestic waste water
while others are affected by domestic and industrial
waste water discharged from Phu Ly town. In some
sections such as the one which receives waste water
from Ha Dong (Mai Linh bridge) and its confluence
with Nhue river (Hong Phu bridge), the water is considerably polluted. All parameters failed to meet the
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Chapter 4: WATER ENVIRONMENT
National Technical Regulation on surface
water quality 08:2008 /BTNMT, type A1.
The water quality at the Day river’s lower
section (from Kim Son - Ninh Binh to the
Day estuary) is better than that in the upper and middle sections. The reason is that
waste water flowing from the upper section
is diluted and the river purifies itself.
Ben De
Nho Quan
Boi River
Dam Tai
Hoang Long River
Loc Ha
Chau Giang River
Dao River
Tributary rivers in the basin
In general, the pollution of tributaries in
Nhue-Day river basin is at different levels.
According to monitoring results, with the
exception of rivers and lakes within Hanoi
City, parameters measuring pollution content on the tributaries of Nhue – Day river
basin still meet the National Technical Regulation on surface water quality 08:2008 /
BTNMT, types A2 and B1.
Cau River basin
Cau River
1.20
1.10
0.80
0.60
0.40
0.20
Many sections of Cau river basin are
badly polluted by industrial activities in the
area with organic pollutants, SS and partially by industrial oil and lubricants (Diagram
4.11). The pollution level in some sections
has tended to reduce in recent years. However, it tends to increase in other sections.
The lower section is the more polluted.
0.00
Gia Bay Bridge
mg/l
There are signs of pollution in the section which runs through Bac Kan province.
Parameters of sources of Type A1 almost
reach the levels provided in the National
Technical Regulation on surface water quality 08:2008/BTNMT. When the river flows
into Thai Nguyen City its pollution level increases considerably, being affected by the
local industrial and mining activities. Pollution parameters collected in some points
in the section crossing Thai Nguyen City
all exceeded the levels set in the National
Technical Regulation on surface water quality 08:2008 /BTNMT, type A1.
2005
Tra Vuon Bridge
2006
2007
Vat Bridge
2008
2009
Hoa Long
QCVN 08:2008 (A1)
QCVN 08:2008 (B1)
25
20
15
10
5
0
Pha
Bridge
Thac
Gieng
Bac Kan
Moi
Bridge
Van
Lang
Hoa
Binh
Son
Cam
Before entrance to Thai
Nguyen province
Hoang Gia Bay
bridge
Van
Thu
Tra
Vuon
bridge
Inside Thai Nguyen city
May
Bridge
Vat
Bridge
Huong
Phuc
Lam
Loc
Phuong
Van
Phuc
Hoa
Long
Thi Cau
Bridge
Yen
Dung
Cross Bac Giang, Bac Ninh province
The lower section of Cau river (which runs
through Bac Giang and Bac Ninh) is affected
73
NATIONAL STATE OF ENVIRONMENT 2010
after receiving water from Ca Lo river in Bac
Giang and Ngu Huyen Khe river in Bac Ninh.
However, its pollution level is still under the
permitted level set in the National Technical
Regulation on surface water quality 08:2008
/BTNMT, type A2.
Cong river, which crosses Thai Nguyen
City, is the second largest river in the basin.
It is affected by activities of tourism boats,
sand carrying cargo boats and waste water
from the mining industry as well as by the
Song Cong industrial zone. Pollution levels
have tended to increase year by year (Diagram 4.13).
Ca Lo river runs through various industrial zones, industrial clusters and urban
quarters in Vinh Phuc province and a part
of Hanoi (Soc Son and Dong Anh districts).
As a result, it is affected by domestic and
industrial waste water.
Ngu Huyen Khe can be seen as the
most seriously polluted river in Cau river
basin. The water in this section is affected
by activities of production businesses, particularly handicraft villages lying in Dong
Anh district as well as the Hanoi to Van An
culvert in Bac Ninh province. The water is
polluted by organic matter; the content of
nutriants at the measured points all exceed
the levels set in the National Technical Regulation on surface water quality 08:2008 /
BTNMT, type A1 many times over, almost
reaching or in a few cases, even exceeding
B2 level (Diagram 4.13).
Dong Nai river basin
The Dong Nai river basin extends
through many provinces and is strongly
impacted by different pollution sources.
The major pollution sources derive from
industrial activities. The surface water in
sections which run through provinces in
the southern key socio-economic area
where many industrial zones and towns
are located is badly polluted.
74
Phu
Cuong
Huy
Ngac
Lake
Nui
Coc
Lake
Nui
Coc
Lake
Mo
Che
Ben Da
Loc
Song
Dam Phuc
Ha
That
Bridge Bridge Bridge Bridge
Cong River
Van
Dao
Mon
Xa
Bridge Bridge
Yen Kim Giang Tan Long Gia
Ninh Son
Tien Bridge Tan
Bridge Bridge Bridge
Bridge
Ngu Huyen Khe River
Loang
Bridge
Others
12.00
10.00
8.00
6.00
4.00
2.00
0.00
Mui
Den Do
Dong Nai Thien Tan
Loi Hoa
Bridge Water Plant's
Port
Pumping station
Ong Buong
Bridge
Hang Da
Port
Binh Khanh
Ferry
Tam
Thon Hiep
Vam Co
EstuaryBridge
Soai Rap
Chapter 4: WATER ENVIRONMENT
Dong Nai river
The water in the section which runs from the
Thien Tan water plant to Long Dai - Dong Nai
begins to be polluted by organic matter, particularly in the section crossing Bien Hoa City.
DO April 2009
DO August 2008
Some sections in the river basin including Thi Vai river (before 2009) were seriously
polluted by waste water discharged from industrial zones. However, with efforts made by
authorities at all levels, the concerned businesses have been compelled to take polution control measures. As a result, the water
quality has somewhat improved. The polluted
section in Thi Vai river has gradually been
purified and the content of dissolved oxygen
(DO) has increased considerably from early
2009 (Diagram 4.16).
Saigon River
Saigon River begins to be polluted by organic matter and microorganisms from the Thi
Tinh river estuary and the pollution increases in
its lower section. The section crossing Ho Chi
Minh City is particularly affected by organic
matter. The content of BOD5, COD and bioorganisms all fail to meet the standards set for
surface water as a source to supply drinking
water (Diagram 4.17).
Distance (km)
45.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Dau
Dau
Ben Thi Tinh Thi Tinh
Tieng Tieng
Suc
River Estuary
Lake Dam base Bridge
Than
port
Phu
Long
Bridge
An Ha
Bridge
An Loc
Bridge
Binh Sai Gon
Trieu
Bridge
Bridge
Nha
Rong
Port
Tan
Thuan
Bridge
Chu Y
Bridge
Other rivers in the basin
The quality of water in other rivers in the
basin is rather good. The content of COD is
still below limits set in the National Technical
Regulation on surface water quality 08:2008
/BTNMT, type A1 (Diagram 4.18).
Groundwater is a component of water resources and an important supply source for
domestic, industrial and agricultural activities.
Currently, between 35 and 50% of the total
water supply to all cities in the country comes
from groundwater reserves.
75
NATIONAL STATE OF ENVIRONMENT 2010
Region
Northeast
Northern plain
Central coast
Groundwater contained
formation
A
B
C1
Loose sediments
15,047
19,150
166,298
31,812
Carbonates
35,284
27,861
190,935
466,031
Other formations
30,592
35,050
102,842
84,960
Loose sediments
353,800
380,726
773,585
1,723,893
Central Highlands
24,377
22,591
110,958
573,965
1,200
26,452
119,917
222,285
Loose sediments
4,000
4,400
107,982
1,503,960
22,280
19,020
133,230
0
1,176
24,988
64,654
Loose sediments
12,000
150,800
232,211
1,417,830
Loose sediments
0
0
10,068
339,138
8,281
26,820
125,244
2,114,663
0
0
1,930
78,462
506,861
714,946
2,108,188
8,721,653
Carbonates
Basaltic
Other formations
Total
Groundwater in Vietnam is rather plentiful due
to abundant rainfall which is distributed widely
and is stored within some major water-bearing
strata. 80% of ground water is pumped from loose
sediments from the Quaternary period which are
concentrated in all major deltas in the country. It
is followed by the carbonate rocks in the northwest, northeast, northcentral and some other
locations, and young weathered basalt which is
concentrated in the Central Highlands and the
southeast. Only very little quantity of groundwater
comes from other geological formations..
Currently, there are more than 300 water
plants and smaller water supply units in cities
and town operating to supply water to people
and industrial activities. Most of them use drilled
wells. Hanoi and Ho Chi Minh City pump the
largest amount of groundwater.
Average depth of drilled wells is less than
100 m for those in the northern, central and
Central Highlands plains and more than 300m
for drilled holes in the Mekong delta.
Currently, total reserves of groundwater in the
country reaches nearly 20 million cu.m, and total
pumping capacity of urban water supply plants is
76
C2
Other formations
Carbonates
Other formations
Southern plain
Supply volume (cu,m/day)
Water supply for domestic and industrial activities in Hanoi
mostly comes from groundwater. Currently in the City there are 29
concentrated large-scale water plants and water supply stations with
a total volume of pumped water of about 650,000 cu.m/day. In
addition to this, there are about 650 industrial wells run by industrial plants with a total volume of pumped water of about 150,000
cu.m/day. So, the total volume of groundwater pumped reaches
more than 800,000 cu.m/day.
Source: Centre for Water Resources Monitoring
and Forecast (CWRMF), 2010
Chapter 4: WATER ENVIRONMENT
about 1.47 million cu.m/day. However, in reality they can use only 60 -70% of their designed
capacity.
Small diameter
In rural areas, the supplied water mainly comes
from small-diameter wells, of the type initiated by
UNICEF, deep wells, driven wells and gravity flow
pipelines. The percentage of rural people who
have benefitted from safe water has considerably
increased over time.
No.
Name of region
Small drilled
wells
Water flow
(cu.m/day)
1.
Northern mountainous region
8080
45331
2.
Red river delta
551157
1634399
3.
Northcentral
21125
61100
Currently, groundwater makes up the largest
percentage in the total volume of water supply
to domestic activities every year. Groundwater
in the northern plain has a high iron content,
so it is treated before supply and the rate of usable water is about 60-70%. Meanwhile, water
plants in central and southern provinces deliver
groundwater directly from wells to pipes without
treatment, or is only treated by traditional techniques.
4.
Central Highlands
2592
9003
5.
Central coast
60835
245609
6.
Southeastern part
136363
1308941
7.
Mekong delta
62798
302164
Total
842950
3606547
Source: Tong Ngoc Thanh (From survey documents up to 2008)
It is very common in southern provinces (from
Quang Nam-Da Nang southward) to pump
groundwater to irrigate crops. Local people have
pumped groundwater to irrigate coffee crops for
many years with a volume of tens of thousands
of cubic meters a day.
Major reasons leading to the decrease of
groundwater quality include geological characteristics of the strata, the endosmosis of polluted surface water, change in land-use purposes and illogical exploitation of water. In
addition, rising sea levels are resulting in salt
water intrusion into coastal groundwater layers.
The impact of those factors is different, and
the consequent groundwater quality is also different, between different geographical regions.
Currently, the quality of most groundwater
sources in Vietnam remains rather good and
meets the requirements for water use: The water is soft (hardness level <1.5 mg/l), its pH
content is between 6.0 and 8.0, and the content of organic compounds and bacteria is low.
The content of heavy metals which exceeds the
permitted level is negligible in most cases.
77
NATIONAL STATE OF ENVIRONMENT 2010
Specific characteristics
Permitted level
Mn
As
Cr
Se
NH4+
Hg
0.5
0.05
0.05
0.01
0.001
0.1
0.68
0.024
0.001
0.001
0.0001
8.70
0.58
0.002
0.008
-
-
0.51
0.59
0.004
0.008
-
0.001
4.24
0.71
0.005
0.006
-
0.000
0.000
0.18
0.001
-
-
0.001
0.05
Northern plain
Average value
Southern plain
Water layer pq3
Average value
Water layer pq2-3
Average value
Water layer pq1
Average value
Central Highlands
Average value
Source: Center for Water Resources Planning and Investigation, MoNRE, 2009
Because of its natural character, the groundwater
in the Quatenary period layers in Cao Bang - Quang
Ninh provinces and loose sediments along river valleys
in Lao Cai - Hoa Binh are polluted by iron.
Meanwhile, groundwater in some other areas is facing saline intrusion on a large scale as well as serious
microorganism and heavy metal pollution as a result
of unplanned pumping and lack of protection of water
sources.
Saline intrusion
Saline intrusion is very common in coastal areas.
Over exploitation has resulted in the groundwater reserve in the soil being insufficient to re-charge the
groundwater layers and as a result, saline water has
intruded into and has destroyed the freshwater layers.
Groundwater in many areas on the coastal edge and
southern part of the northern plain and the whole of
the Mekong delta is badly affected by saline intrusion
and fails to meet the requirements of drinking water.
Microorganism and heavy metal pollution
In addition to over exploitation, industrial activities
have discharged a large quantity of pollution into the
environment. The pollution is distributed by surface water, infiltrating into groundwater layers and subsequently
polluting them. Coliform pollution has been detected in
many areas and the pollution level is hundreds to thousands times higher than the permitted level.
78
Currently, many households in Ho Chi Minh City are
using seriously microorganism polluted water. 54% of
the 107 water samples taken from households living in
Precincts 9 and Thu Duc, Binh Chanh, Hoc Mon, Nha
Be and Cu Chi are seriously affected by microorganisms
(E.coli, Coliform, Coliform fecal) from 2,100 to 3,700
MPN/100ml. Meanwhile, regulations provided by MOH
do not allow those microoranisms in drinking water.
Recent reports by Ho Chi Minh City’s DONRE show
that the quality of groundwater in Ho Chi Minh City has
reached an alarming level, particularly water in the second layer (out of the 3 layers of groundwater).
Source: HCM City’s Center of Drinking Water and Rural
Environmental Sanitation and the City’s Center for Preventive
Medicine, Feb. 2009
Chapter 4: WATER ENVIRONMENT
Sign of phosphate pollution has been detected in
groundwater in Vietnam and the pollution level tends
to increase with time. In Hanoi, 71% of well water
has a P-PO4 content higher than the permitted level
(0.4 mg/l).
Analysis of chemical composition of groundwater
in Hanoi showed that water from both the Holocene
Groundwater in some areas in Ha Giang and
Tuyen Quang provinces has an iron content higher
than the permitted level, often more than 1mg/l and
even more than 15 - 20 mg/l in locations around the
sulphur mines.
(qh) and Pleistocen (qp) layers has amonium, asenic
The over exploitation of groundwater from the
holocene layer has increased the asenic content to
a level which exceeds the permitted level of 10mg/l.
Notably, the distribution of arsenic affected areas are
almost the same as areas having high amonium content. This is very common in the northern plains and
the Mekong delta.
pounds tend to increase with time in both content and
and organic contents higher than permitted levels.
Asenic content in groundwater in Hoai Duc area
is higher than 20mg/l, and the amonium content in
Ha Dong town is higher than 100mg/l. These comcoverage. Chemical compounds are concentrated in
areas which have landfills and industrial zones, and
downflow areas as well as waste water concentrated
areas such as Thanh Xuan, Thanh Tri, Hoang Mai, Tu
Liem, Gia Lam and Long Bien, Dan Phuong, Hoai Duc,
Thanh Oai and Ha Dong districts. Groundwater in Phu
Xuyen and Thuong Tin has a mineral content higher
than 1g/l.
Source: Center for Water Resources Planning
and Investigation, 2009
Pressure of population growth and urban development in coastal areas
Population growth in coastal areas has increased
the quantity of solid waste and waste water which is discharged into the environment and the sea through rivers
and canals. The quantity of waste is highest in coastal
cities and towns where socio-economic activities have
Type of waste
Average
quantity
Unit
Total quantity of waste
discharged from coastal
provinces
Unit
Solid waste
0.35-0.70
kg/people/day
5,200-10,300
ton/day
Waste water
80
L/people/day
11,800,000
m3/day
Suspended matter
70-145
g/people/day
1,030-2,140
ton/day
BOD5
45-54
g/people/day
660-790
ton/day
COD
85-102
g/people/day
1,250-1,500
ton/day
Amonium (NH4-N)
3.6-7.2
g/people/day
50-100
ton/day
6-12
g/people/day
90-180
ton/day
Total Phosphate
0.6-4.5
g/people/day
9-66
ton/day
Non-mining oil
10-30
g/people/day
150-440
ton/day
Total Nitrogen
Source: Institute of Mechanics, 2010
79
NATIONAL STATE OF ENVIRONMENT 2010
developed and attract more labourers from other cities
and provinces.
Currently, there are almost no treatment systems for
solid waste and waste water in coastal cities. As a result,
the pressure of waste discharging into the coastal environment has become very serious.
Pressure of maritime activities
Waste water is also discharged from ocean-going
ships, other maritime facilities, ship building and repair plants, seaports, and freight yards and stores.
Industrial waste water discharged from these sources
contains significent mineral oil, detergents and heavy
metals which seriously threaten the quality of sea water and waste water receiving areas. In recent years,
about 400 units of international shipping passes
through Hai Phong - Quang Ninh seaport complex
every month and the discharged ballast water is estimated at about 430,000- 710,000 cu.m. In 2008
alone, the quantity of waste water and oil mix released
from 394 ocean-going ships to Hai Phong port was
4,578 tons, including 2,561 tons of waste oil.
In addition to this, sea accidents cause chemical
and oil leakage which also affect the marine and
coastal environments.
Pressure of fishing and aquaculture
Aquaculture areas (in brine and brackish water)
has increased in recent years. As part of the rearing
process, this industry discharged into the environment
considerable waste food matter and antibiotic residue which seriously pollute the coastal waters. Many
locations develop aquaculture in estuary areas which
degrade or even destroy many eco-systems such as
the mangrove forests, seaweed and tidal areas. In
addition, the use of hazardous chemicals in fishing
activities has also increased the pollution level.
The pressure of coastal resources exploitation has
reached an alarming level with more than 80% of
fishing boats concentrated in coastal areas. The sustainable fishing output in areas which are less than
50m deep is estimated at 0.6 million tons while the
actual output has already reached 1.1 million tons.
Pressure of coastal industrial development
The rapid development of coastal industrial zones
and economic areas (which make up 79% of industri80
Chapter 4: WATER ENVIRONMENT
al zones in the whole country) has put more
pressure on the marine environment.
Coastal areal
Whole country
Waste water from coal mines has a negative impact on the coast. It silts up the coastal
estuaries, destroys marine creatures and reduces the water quality. Every year, coal mines
release about 25-30 million cu.m of waste
water to the environment with a high acid
content (the pH of coal mines’ waste water is
about 3.1-6.5). Solid waste discharged from
coal mines is about 150 million cu.m a year.
Landfills in Quang Ninh, particularly in areas
close to Ha Long and Bai Tu Long bays, badly
pollute the local marine environment.
The oil and gas industry also poses big risks
to the environment. The risks of oil leak during
the exploitation and transportation process, as
well as hazardous pollution, are very high.
Pressure of coastal tourism development
Solid waste and domestic waste water
from tourism services, specifically tourists’
activities, directly pollute the surface water
in areas close to hotels, guest houses and
other tourism and travel-related facilities. In
Vietnam, waste water from coastal areas,
where tourism contributes a major part,
makes up one fourth of the total quantity of
waste water from the whole country. In addition to the over exploitation of water supply to meet the needs of the tourist industry, tourism also increases the risk of water
source pollution.
a
Tr
Co
Cu
a
Lu
c
Do
So
n
Ba
La
t
Sa
m
i
t
n
h
n
g
o
o
g
et
uy Tau
An ang
An Gia
ua
Ho n C
yn
ho
an Thi
an
So ua L
Q
n
Q
h
N
nh
Tr
u ng
Hu y N
ng
Ng
ua
C
Co
a
Di Rac
ng
an
u
o
Ph Vu
Da
Do
Th
Sa
Q
Nh Ph
Du
De
Total suspended solids (TSS)
TSS are mainly carried to the sea by rivers.
Therefore TSS content is often high in coastal
areas of the northern and Mekong deltas,
particularly in estuaries such as Ba Lat, Dinh
An and Rach Gia. The content of TSS is lower
in the central coast than other locations and
has tended to decrease over the 2005-2009
period.
81
NATIONAL STATE OF ENVIRONMENT 2010
Chemical oxygen demand (COD)
Annual average COD content in coastal water in
the 2005-2009 period tends to increase along the
southern coast where annual average COD in water oscilates between 11.23 and 20.50mg/l and all
monitored values are generally higher than the permitted levels set in QCVN 10:2008/BTNMT (4mg/l),
with particularly highs in 2006 and 2008. Meanwhile
on the northern coast, annual average COD content
does not exceed the National Technical Regulation
with the exception of water in areas, strongly affected
by river water such as Cua Luc and Ba Lat estuaries
and Do Son beach often has a higher COD content
than other coastal areas such as Tra Co, Sam Son
and Cua Lo.
Amonium content
In general, the content of Amonium (N-NH4+) in
the northern coastal waters is higher than that in the
central and southern coasts. In Cua Luc, Do Son, Ba
Lat and Rach Gia estuaries, the amonium content in
82
Chapter 4: WATER ENVIRONMENT
coastal water where aquaculture and marine conservation projects exist, all exceed standards set in the
National Technical Regulations.
Oil content
Oil pollution along the coast has been a problem
of special concern because of its serious impacts on
the coast and its direct relation to aquaculture and
coastal tourism.
In all monitored areas, the average oil content
in coastal water in the 2005-2009 period did not
meet the requirements set in the National Technical Regulation for coastal water used in aquaculture
and marine life conservation. Most of the monitoring values in fact exceeded the regulations for any
use purposes.
Along the northern coast, the oil content in
coastal water shows clearly the impact of marine
transport activities on water quality. The oil content
in water at Cua Luc estuary measuring point, which
83
NATIONAL STATE OF ENVIRONMENT 2010
Tra Co
Cua
Luc
Do Son
Ba Lat
Sam
Son
Cua
Lo
Deo
Ngang
(*)
Dong
Hoi
(*)
Con
Co
(*)
Thuan
An
(*)
is close to Cua Luc passage and Bai Chay ferry is
far higher than that in the water in other measured
points. Along the central coast, the oil content in
water increased suddenly in 2007, particularly during the monitoring visit in the 1st quarter of 2007.
The unknown source of the oil leak detected in February 2007 badly affected 20 coastal provinces and
cities, particularly central provinces. Total oil quantity collected was higher than 1.7 thousand tons. The
oil content in sea water in the southern coast tends
to increase steadily each year.
Cyanide content
In the 2005-2009 period, the cyanide content in
water along the northern coast tended to increase
from 2005 to 2008 and reduced in 2009. The trend
in the central coast is not clear, but the monitored
value was higher than that in the northern coast.
Monitoring of Cyacide content in water along the
southern coast has not beencarried out yet.
84
Da
Nang
(*)
Dung
Quat
(*)
Sa
Huynh
(*)
Quy
Nhon
(*)
Phu
Quy
Nha
Trang
Phan
Thiet
Vung
Tau
Dinh
An
Rach
Gia
Chapter 4: WATER ENVIRONMENT
µg/l
Monitoring of water used in aquaculture, marine
life conservation, seaside resorts and entertainment
centers on the central coast showed a higher cyanide
content than the permitted level (5μg/l), particularly
in Sa Huynh area, the cyanide content monitored in
2006 exceeded the regulation set for all water use
purposes (1μg/l). This development resulted from
the use of cyanide in fishing activities.
Content of heavy metals
Monitoring results showed that all indicators of
pollution of heavy metals such as copper, lead, zinc,
cadmium, mercury and arsenic are within the permitted limits according to National Technical Regulations for coastal water quality 10: 2008/MONRE.
Only the water in Ba Let showed signs of pollution,
where all indicators were higher than the limits set in
the National Technical Regulation for water used in
aquacullture and marine life conservation.
Content of Dissolved Oxygen (DO)
The DO content ensures the quality of water used
in marine life conservation (ASEAN permitted standards). The content of DO in water in the southwest
sea is lower than others.
85
NATIONAL STATE OF ENVIRONMENT 2010
Standard
Marine area
86
Chapter 4: WATER ENVIRONMENT
Nutrition Content
The nutrition content of sea water is
lower than that in coastal water. However, water in the southwest and Con Son
high seas has a higher content of nutritious substances than other areas.
2006
µg/l
2007
2008
ASEAN Standard
2009
140
120
100
80
60
40
20
0
Southern
Southern
Western
Southern
East oil
East
Spratly
West area
potential
Islands
exploited
Content of heavy metals
Con Son sea
East (1)
West (2)
petrol area
Marine area
The value of heavy metals content in
sea water is by far higher than that in
coastal water.
Coastal area
Oil content
Oil content in sea water is lower than
that in coastal water. However, water in
the oil and gas exploiting area in the
southeastern seas has a higher oil content than other seas. Most values are
higher than ASEAN standards (0.14μg/l)
for marine life conservation water.
Standard
12.00
10.00
8.00
6.00
4.00
2.00
0.00
Southern East Southern East
oil exploited potential petrol
area
Western
Spratly
Islands
Southern
West area
Con Son sea
East (1)
Marine area
West (2)
Coastal area
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Southern East
oil exploited
Southern East
potential petrol
area
Western
Spratly
Islands
Marini area
Southern
West area
Con Son sea
East (1)
West (2)
Coastal area
87