Final report on :
WATER FNVINRONMFNTAL QUALI1Y
OFHALONG BAY, VIETNAM
By: Working Group of WEQHB project of HIO
Chief Editor : Dr. Nguyen Chu Hoi Secrectariat : B. Sc. Luu Van Dieu
Submitted Jointly to : VISED, IDRC, MOSIE and HIO.
Haiphong, March, 1995 Acronyms:
HIO : Haiphong Institute of Oceanology IDRC : International Development Research Center MOSIE : Ministry of Sciens, Technology and Envinroment WEQHB: Water Environment Quality of Ha Long Bay VISED : Vietnam Sustainable Economic Development ESSA: ESSA Technologies Ltd. NEA: National Environment Agency of MOSTE DIC : Department for International Cooperation of MOSTE 1-ILBMP : Ha Long Bay Master-Plan Contents Page
Introduction Nguyen Chu Hoi 1
0Japlcr [. G(!n~ral issues 3
1.1. Geographical limits Nguyen Chu Hoi 3
1.2. Research scope Nguyen Chu 1-/oi 3
1.3. Main socio - economic characteristics Nguyen Chu Hoi 3
1.4. Morphological and Geomorphological features of the Halong Bay Dinh Van Huy 6
1.5. Geological feature of I-I along bay area Tran Dinh Lan 8
1.6. Main ecosystems Nguyen Chu Hoi 10 Pham Dinh Trang
1. 7. Human activities Tran Dinh Lan 12
Chapter 2. Methodology Luu Van Dicu 14
2.1. Station net work 2.2. Duration 2.3. Equipments 2.4. Collection and Preservation of samples 2.5. ;\nalyzing methods 2.6. Parameters 2. 7. Prosessing results
Chapter 3. Physical condition of Halong area 18
3.1. Clitnate Do Dinh CIJicn 18
3.2. Marine hydrology Do Dinh Chien 19
3.3. Fluvial hydrology Do Dinh Chien 20 3.4. Hydrochemical characteristics in Halong Bay Pham Van Luong 25
3.5. Comments Pham Van Luong 36
D1aptcr 4. Biological charateristics in Halong Bay 37
4.1. Phytoplankton Chu Van Thuoc 37
4.2.Zooplankton Nguyen 7hi 7hu 42
4.3. Zoobenthos Pham Dinh Trang 43 Lang VanKen
4.4. Marine algae and seagrass Le Thi Thanh 53 Nguyen Van Tien
4.5. Fish Nguyen Nhat 7hi 53 54 4.6. General remark Lang VanKen
OJaplcr 5. Present status of Ha Long Bay water environment 55
5 .1. Organic pollution Luu VanDicu 55
5.2. Oil content in water Luu VanDieu 64
5.3. Pesticides residues in the Ha Long waters Pham Ngoc Hung 66
5 .4. Heavy metals Luu VanDieu 68
5.5. Nutrients Pham Van Luong 72
5.6. Sulphate content (SO/-) Luu Van Dieu 85
5.7. Microorganisms (Escherichia coli) Dam Due Tien 86
5.8. Transparency and light penetration Tran Dinh Lan 88
5.9. CmTent status of garbage in area Tran Dinh Lan 92 Ch~p!cr 6 A<>scssment of Ha L.ong Bay Water Quality 93
6.1. Pollutants. Luu VanDieu 93
6.2. Pollutiant sources to Ha Long Bay Waters Luu VanDieu 94
6.3. Perliminary assessment of the impacts of the pollution on the health of dwellers and ecosystems. Lang Van Ken . 95
6.4. Ha long Bay waters environment in the future Luu Van Dieu 96
Conclusions and Recommendations. Luu Van Dieu 97
Main references 98
Annex 1. Illustration photographs of the survey 99
Annex 2. Illustration photographs of Human activities 102
Annex 3. Long-term water Quality Monitoring 107 (tentative Proposal second phase)
Annex 4. Chromatograms of Gas Chromatographic Procedure for Organochlorine Pesticides 109
Annex 5. Chromatograms of Infrared Specctrophotometric Procedure for oil contents 119 Annex 6. Bottom relief of I Ia Long Bay illustrated on echo sounding papers.
122
Introduction:
• Vietnam is major marine country in Southeast Asia. Like other countries in the region, Vietnam is faced with a number of resource and environmental issues within its coastal zone such as: marine pollution, loss of marine biodiversity, over-fishing ... Because of this, Vietnam recently have adopted a environmental framework entitled National plan for Environmental and Sustainable Development and Environmental protection Law of Vietnam.
• Ha Long Bay is an area of unique natural beauty and has been adopted the natural World Heritage by UNESCO in its 18th annual meeting. It contains numerous limestone islands, coastal and marine ecosystems. So Ha Long Bay attracts thousands of tourists ( both domestic and foreign) every year. Ha Long Bay is one of five top tourist destinations in Vietnam according to World Bank (1992), It held about 10% of total visitors. Other important activities in the study area include fishing, small scale industries and manufacturing. In Hong Gai estuary, just in North of the study area, there arc a number of port industry facilities.
• Ha L.ong city have just been established by Vietnam's government in 1994. The city will cover the study area and its upland area. So environmental impacts of the development project in the future will appear. Because of the environmental importance, IDRC and VISED have assisted the HIO a grant to undertake water quality assessment in I-Ia Long Bay. The purpose of the Grant as following: - To investigate the contaminants, their sources and their influence on environment quality in Ha L.ong Bay waters. - To assess their environmental impact on ecosystem and their influence on the economy. - To provide for the forcca'iting of pollution intensity in the future. The project involved the participation of the scientific staff from Haiphong Institute of Oceanology (1-IIO) in some fields of marine pollution monitoring, marine ecology, marine geo-environment and coastal management. These scientists were ·,'-,>rking in close collaboration and heartfelt support of technical and management experts of IDRC, ESSA and VISED (Canada). This document is the final report of WEQI-IB. It provides the research results concerning the water environmental quality in 1-Ia L.ong Bay based on original fieldworks, sampling and data collection, as well as analytic results. It also combined with synthesizing existing data from other sources. First, the document also provides baseline information about environmental quality which could be prepared for use in Master Plan in Ha Long Bay area. It will help us to plan environmental monitoring strategy for long-term in Ha Long Bay for the next step.
This document is the product of input from many HIO researchers, from Canadian experts (IDRC, ESSA, VISED) and other, who has participated and advised in the project. We particularly wish to thank the international experts for their hard work and effective help in process of project implementation. Dr. W.R. Spence , Regional Director and Dr. Stephen R. Tyler, environmental expert, and o~her from IDRC have had valuable comments, opinions for project establishment and fonnulation of interim reports. Mr. Ashley J. Bansgrove from ESSA Technologies Ltd. has been the technical advisor of the project. Dr. Jingjal Hanchanlash has timely supports and project management. Finally, we also thank very much Prof. Le Qui An, vice-minister of MOSTE, Dr. Nguyen Ngoc Sinh of NEA, Mr. Dau Dinh Loi and Mr. Thach Can of DIC, who assisted in the formulation and implementation of the project. The errors of the report is inevitable due to limitation of the time and English languages, as well as lacking knowledge and experiences of research staff. So we would like to receive opinions of the experts and others.
2 Chapter 1. General issues
1.1 Geographical limits
I-Ia Long Bay study area is located in Quangninh province, Northern Vietnam (fig.l ). It is bordered to the Northern by Bai Tu Long Bay, to the South by Cat Ba islands, to the West by land area Quangninh province and to the East by nearshore water of the Tonkin Gulf. The study area includes two water bodies : Baichay embayment and Ha Long bay, linking with each other by Cua Luc inlet of 600m in width. The water surface area of Baichay embayment 2 and then into Ha Long Bay is about 27 km • The water of rivers are coming directly into Baichay embayment and then into Ha Long Bay throughout Cua Luc inlet.
1.2. Research Scope.
Under the items of the Grant, surveying and assessment pertaining to water environment in the Ha Long Bay have been carried out by 1994. For purposes of the WEQHB project, the HIO and ESSA have defined the I-Ia Long Bay study area consisting of coastal waterbodies, small islands and portions of adjacent upland (fig.l ). There has been very little scientific investigation of marine water quality in Ha Long Bay, and no long- tenn monitoring of any type. It is difficult to comment on current water quality conditions. Thus the key parameters of water environmental quality have been and taken, as following: Safjnity, DO (Dissolved Oxygen), COD (Chemical Oxygen Demand}, BOD (Biochemical Oxgcn Demand), S'M (Suspended meller), Turbidity, Clarity (Secchi disk}, oil, total pho!>phorous, Nitrogen-nitrite (N02), Sulphate (S04}, Heavy metals {Cd, Cu, Hg, Pb}, Pesticide, Fecal Colilorms. In addition, the depth of water, water circulation, biodiversity, bottom sediments and plankton have been newly calculated and collected.
1.3. Main socio-economic characteristics.
• Population and heath ofdwellers.
Population of Quangninh province is approximately 814,000 among which are 12,000 persons in Baichay and 1-Iongai towns. Ar.; estimated by the local authority, there are ten thousands of visitors coming to have short rest in Baichay every year. I
Women labors among which arc 90% working in hotels hold 60% of the total population. 111e rest of women labors arc working on fishery, agriculture and light industry. W hat is more, half of annual visitors who just like swimming are female. Actually, to solve the
3 problem of Halong bay water environmental quality depends largely upon how to solve gender issues. It is women who should be educated at an obligated level of the environment and environmental protection.
However, environments have influence, in tum, on health of dwellers and especially children. From the data of Vietnam- Swedish hospital in Quangninh, there arc 92 diseases often occurring to the children, among which arc 22 diseases found to be the most common, namely.
The diseases which have been found to be the most frequently are and nose and throat inflammation, pneumonia, diarrhoea, dysentery, hemorrhage fever, decline, prodrome of cancer, mcnin gilis and kidney inflammation.
Children often get the disease of nose and throat inflammation, pneumonia, pleurisy and diarrhoea.
Hemorrhage fever sometimes develop into an epidemic disease (in case of the epidemic in 1987, 2,098 persons were diseased). Prodrome of cancer is dangerous disease, but its patients are relatively high. The appearance of various diseases may be related to environments. ·
• Urbanization A" following of development of the country in recent years, urbanization in this area has been expanding rapidly. Particularly the foundation of "Ha Long city" including 1-longai and Baichay towns in early part of this year and future development plans such as Mater plan of Ha Long Bay ... make urbanization more and more violent. Nowaday, the domestic waste by 120,000 persons in coastal area comes directly into the bay without any treating way. In the future, population will be increasing then there will be more waste to penetrate into waters. The construction of infrastructures such as : roads, bridges, buildings, populated areas ... requires flat place for the urbanization. This is why the forest area has been reduced (from approximately 70'1c to 26% now and reducing in future). Another reason for this is over exploration of fuel wood ... Because of these, tendency of flood is increasing and wastes (both liquid and solid) in wastes of temporal streams and rivers flow directly to the bay. On the other hand, the penetration of surface water into the ground has reduced and power of streams have carried solid waste has been intensified.
• Traditional specificities in the coastal area composes coal mining, fishing, processing coal and sea products port and navigation, tourism and some haudicrafts. All sections have been developing for long time, but now there is any kind of treating their wastes and wastes (gas, liquid and solid) arc changed into the bay.
4 Table 1.3.1 The state of diseased children in Quangninh province during the time 1985- 1993.
Number of No Diseases patients in a _year
1 Nose and throat inflammation 413 2 Pneumonia 819 3 Pleurisy 48 4 Dysentery 198 5 Diarrhea 875 6 W hooping cough 69 7 Measles 60 8 Hemorrhage fever 218 9 Kidney inflammation 109 10 Hepatitis 18 11 Brain rever 68 12 Septicemia 48 13 Intussusception 83 14 Diabetes 4 15 Decline 219 16 W eakly horn bodies 181 17 Prodrome of cancer 217 18 Poisoned 18 19 Meningitis 105
5 1.4. Morphological and Geomorphological features of the Ha Long Bay.
1.4 .1. Morphology.
The Ha Long Bay, a coastal water body with an area of 120 sq. km. is surrounded by about 200 limestone islands in the cast and the South, Tuan Chau island in the west and by sandstone hills in the North, and communicating with the Bai Chay embayment, a water body of 30 sq. km. in area.
Communicating with the sea outside through 10 deep channels for navigation CHon Gai, Cat Nang, Hon Mot, Dau Trau, Ac, Gom, Genh Cam, Vcu, Cap Sau, Ba Hen, etc.), the 1-Ia Long Bay satisfies the reads of marine transport in the region.
On average, the Ha Long Bay is about 2.0 m deep and 30-40 per. of the floor is 2.0 m deep and deeper. The maximum depth is 20 m in the Luc Channel and 24 m in the Dau Trau Channel. The floor is gently sloping toward the South with an inclination of 0.001- 0.006 and little engraved by channels because most of them are located in the lateral {except the Hon Mot channel which separates the floor into two parts, the West is 3 times larger than the East.
1.4.2. Geomorphology.
The following are landfonns noticed on the genesis and dynamics of development.
1.4.2.1. Beaches.
Beaches are small in side, about 30-120 m wide and 300 m up to 1200 m long, along the coast of Tuan Chau island and Bai Chay. They are constructed mainly by storm waves (1.5 m high) and southeast wave front (0.25-0.5 m high).
1.4.2.2. High tidal flats.
High tidal flats on which fine sediments arc constantly accumulated and mangroves arc dense develop into a green belt of the tidal zone and are located at a high rang of 2.1- 4.5 m above the lowest low level.
1.4.2.3. Low tidal flats.
Located up to 2.1 m higher than the lowest low levels, they hold a major part of the tidal area, "and are covered by coarser sediments and no vegetation.
1.4.2.4. Sea level marks by chemical erosion.
Surrounding limestone islands, the sea level marks formed by both chemical solution and wave erosion arc cutting the base of clifts and developing into hollows with up to
6 some metres in size dependent on the li·.tological composition of rock. When the hollow is deep enoug~, the cliff overhanging above can be collapse and the sea level mark will develop a new hollow. ·
1.4.2.5. Bed form.
It is the largest surface fmmccl by accumulation of silt, mud, sand, gravels with debris of shells. It is 2 m deep, gently sloping toward the southeast.
1.4.2.6. Tidal creeks and channels.
Tidal creeks with the base at the lowest low level of tides and higher develop densely in the tidal zone and undercut tidal flats into small islets.
On the floor, there arc tidal channels coming from the old elongate depressions or gullies before the Flandrian transgression. Most of the channels have been constantly eroded by tidal currents but some of the others or parts have been filled slowly with fme sediments. The eroded channels arc narrow and deep, located between the island. They arc 20 m deep or deeper.
7 1.5. Geological feature of Ha Long Bay area
The area is in Hong Gai depression, which is between Yen Tu and Cat Ba -: Co To rifts, with the Paleozoic and Mesozoic sediment rock base such as Carboniferous sediment rocks aged Trias in coastal zone, Carboniferous - Permian limestone on islands and the bottom of 1-Ia Long Bay. Basins formed in neotectonic period were filled by Neogene sediments containing brown coal. Quaternary sediments cover coastal area and around islands. Formations in the Pleistocene consist of marine sediment and material of river fans. Sediment in the Holocene were originated from rivers and submarine. In component of alluvial, there arc minerals of ilmenite, leucoxene, rutile, monazite, anatase, rare minerals, such as Gold, Cinonabar, Cassiterite and dispersal fringes of Mercury and Ce La.
Recent sediment on the bottom of Ha Long Bay composes of sands, aleurites and pelites. Sands are observed on beaches of Bai Chay seaside and on tidal flats in Bai Chay embayment and on beaches around Tuan Chau island. Aleurites distribute on tidal flats around limestone islands and Tuan Chau island, on the bottom of channels with strong tide currents and of the Bai Chay embayment. Most of bottom area are covered by pclites.
The fraction less than 0.05 mm in bottom sediment of Ha Long Bay ranges from 22% - 78% but this one in llai Chay embayment bottom sediment doesn't exceed 20% and the predominance is of coarse factions (classes of 0.05 mm - 0.1 mm and 0.1 mm - 0.2 mm). It is, showed that there have been influences of inputs from rivers and streams in adjacent area (Fig.l. !}.1).
Particularly, from the result of the survey in July, 1994, there is a concentration of coal in bottom sediment and somewhere the concentration exceeds 10% in the fraction coarser than 0.05 mm. This one is high in areas near the coal mining places and ports. Besides this, organic matter is often concentrated on North-South axis through Luc inlet.
Heavy minerals in sediment can be grouped in two assemblages: The first one consisting of leucoxene - tourmaline - ilmenite is characteristic for Bai Chay embayment and I-Ia Long Bay. The second one composes of tourmaline - zircon - ilmenite and silimanite - garnet - stauronite having poor roundness. It is said that minerals in this assemblage was resulted from rock base under the basin. ----··--1.0.1?.1"107" ' (d '
1)lJ
• ···., ..... • ..... :·
Fig{5.1. , Spatial distribution of percentages bottom sediments with particle sizes less than 50 ~tm in 1994
LE • <30% • 30-50% • 50- 70% • >70% 9 1. 6. Main ecosystems some of the coastal and marine ecosystems characteristic of Ha Long Bay study area will be shown in the table 1.6.1 On rocky littoral, especially on benches with boulders around islands called Trinh nu, Mat qui, Co ngua, Hang luon, Bo hon, l-Ion dam, May den, etc. , invertebrate faunas consist of typical representatives such as : Balanus spp., Crabs-families Portunidae, Xanthidae, Grappsidac, Snails of Nereidae, Potamididae, Muricidae, Cypraeidae, ( Shell money), Trochidae, some of bivalve molluscs of Arcidae (Area spp.), Ostreidae ( Otrea spp.), Mytilidae (Brachydontes spp.,Mdiolus spp.) and black Holothurians. On marshy littorals of Cai Dam, Vai islet, Dau Go cave, there are some of other Crabs ( Ocypodidae, Grapsidae, ect. ... ) and Polychaetes. Mangrove forests distribute on Fruit- Garden, Tuan Chau, wood - head cave with plants of Avicenia marina without distorting mangrove forest, plants can be 2 meters in height and on the contrary , at other places, plants are shorter, smaller, thinly populated and regenerated . 1l1e fauna of Zoobenthos is composed of Balanus spp., Area spp.) and Sipunculids. They are important objects of coral (both hard and soft) reefs arc found only in the South around Trinh nu , May den, Co ngua islands, ... On these reefs, 4 species of Area, 3 species of Mytilidae, 5 species of Crabs, 6 species of Snaifs, 8 species of Polychaeta and 3 species of echinoderms have been found. The sublitoral water of this bay also are the exploiting ground for commercial Shrimps (Parapenaeopsis spp., Penaeus spp.) According to the survey materials in 1971- 1972, the mean densities and biomass of Zoobenthos in these waters of the Bay are in Tablcl.6. 2. 10 Table 1.6.1. Coao;;tal and marine ecosystems of 1-la Long Bay area Ecosystems Characteristics aquaculture systems • backish water fish and shrimp. (limited) • frequently_ reclaimed from mangroves beaches (very limited) • important for tourism estuaries and embayment • semi-enclosed, brackish water • important fish/shrimp spawning, nursery and feeding areas. mangroves and wetlands • a~ong shoreline zone of Ha Long Bay and Baichay embayment. • important for shrimp, crab production • shllon water of the islands in the Bay. seagrass beds (very little) • salt - brackish water. • unique ecosystems, often no predactors. islands • limestone small islands with beautiful caves • important for sea birds and sea turtles • tourism potential • salt water soft bottom • important for benthos • important for invertebrates, fish, sea turtles and coral red dugongs. • very fragile and sensitive. Table 1.6.2. Density and biomass of zoobenthos in Ha L.ong Bay and adjacent area Time Ha L.ong Bay Adjacent waters (month - year) (inds. - gr per sq.m) (inds. - gr per sq.rn) 9- 1971 31.06 - 0. 96 30.00 - 0.93 12- 1971 25.60- 13.00 32.30- 3.70 2- 1972 24.08 - 2.16 42.9 - 1.93 11 1.7 .Human activities. • Port and navigation lines have a direct effect on water environment quality of Ha Long Bay. Most of ports and harbours in Quangninh province are concentrated in coastal area such as Cailan, Hongai, B12 oil port and domestic and international navigation lines across the bay consist of: Haiphong- Quangninh, Hongai- Campha, 1-Iaiphong-Catba lines and Haiphong- foreign , Hongai- foreign lines ... Besides these, there exist many small harbours along the coast and islands of Halong Bay. • Industrial development is increasing . A part from long aged industry such as factories processing coal and sea products, four brick fields (Halong, Giengday, Hakhau ... ), there have been new factories of Halong beer, Halong building ship and sections consisting of tourism, coal mining and a lot of small scale manufactories. Their waste have been carried directly into 1-Ia Long Bay water without treatment in any way. It is estimated that there are 12,000,000kg of solid waste from all factories charged into waters of Ha Long Bay every year. • In particular, coal mining is an over hundred developing section. In present, in Quangninh province, there arc five surface coal mines, seven coal mining wells and about hundred small scale mines. In Hongai area, there arc five mines having significant effect on environment (1-Iatu, Halam, Caoson, Caothang, Thongnhat). W astcs arc in fonns of solid, water. dust and gas. W aste from Thongnhat mine, for example, is from 1 ,500 to 2,000 m3 per 24 hours, dust concentration in the air is 3 98mg per m with 93-96% of grain size under 5J..tm measured where explosives are used to mine, an currents from well carry 113.17 kg of mud per 24 hours. ~ Bccau~e of its natural beauty, I-I along attracts a lot of visitors every year and tourism operations have developed intensitively. There exist 26 nationalized units have tourist services in independence, about 26 guest houses with 1096 rooms in all, 10 mini hotels, about 60 servicing boats. On the bay, there arc 12 limestone islands with unique caves that arc usually visited (e.g. Daugo, Bonau, Trinhnu, Doi, Trang, Loun caves ... ). In 1992, it was estimated that Halong bay attracted 2,000,000 tourist visitors. Accompanying tourist grow, domestic wastes which are not treated in any way is more and more such as :stuff paper, dink cas, plastic envelopes, empty bottles, pieces of trees on beaches and waters. • Halong bay is also a potential fishing field. Fishing is performed on small boats with many kind of nets, besides this, living life on beaches and tidal flats is caught b~ dweller with handle instruments. Baichay and Hongai beaches are places of marketing sea products and fuel for fishing boats. Noted operations take part in polluting water environment with wastes from fuel loss in loading and transport and putrid sea products. • The effects of fertilizer, pesticide and insecticide from agriculture area in the north of Hongai estuary and livestock breeding and cultivation in the hills and urban sewage on water environment of the bay through the local streams and river that drain 12 directly into the bay are possible. Besides these, it is said that there will be a 1 ,200 ha reclamation project in the north of Hongai estuary and if the project is c~ried out, there will be impacts on coastal and water environments. Table 1.·7.1 Human activities pertaining to water environment quality of I-Ia Long Bay Rank Human activities JSSUCS. 1 Port and navigation - Hongai coal port, B 12 oil port and many coal harbours on coastal area. - four navigation lines across the bay and several lines adjacent to the bay. -four brick fields (I-Ialong, Giengday, Hakhau ... ) and 2. Industrial development factories of processing coal and seaproducts. - new factories of 1-Ialong beer, Halong building ship. - other sections : tourism, coal mining. - many small scale manufactories. -five mines: Hatu, I-Ialam, Caoson, Caothang, Thong Coal mining nhal in Hongai area. 3. - waste water from mining of from is l ,500-2,000m3. - dust concentration in the air is 98mg/m3 - air currents from well mining carry ll3.17kgs of dust per 24hours. - 20 guest houses with l 096 rooms Tourism operation - 10 mini hotels 4. - 60 servicing boats - about 2,000,000 tourist visits in 1992 - boats equipped with many kinds of nets Fishing and maketing - 1-Iongai market and adjacent area arc places of buying 5. seaproducts and selling scaproducts and fuel for boats. - fertilizer, pesticides and insecticides from agriculture Livestock breeding areas were charged into the bay through streams -a 1,200 ha reclaimation project will be done 6. and cultivation 13 Chapter 2: Methodology 2.1. Station network. Station network is carried out from modified Triangular Grid (see Fig.2.1.). There arc 3 stations for repeatedly sampling in 24 hours and 12 spatial stations, among which are 1 station (No 4) for taking samples every 2 hours. Two are (No 6 and 12) every four hours. Hydrochemical factors, plankton and suspended matter were taken in both surface and bottom layers. The stations were located from the National marks and local marks set up along the coast. 2.2. Duration: 19 -31 July, 1994. 2.3. Equipmenl~: A motorboat of 23 CV was used to work on the sea and a car used to work in the coast. Two water samplers (1 litter and 4 litter volume) were used for collecting hydrochemical and plankton samples at two layers (surface and bottom). Pcterscnd Grab was used for taking sediment and zoobenthos samples. 2.4. Collection and preservation of samples : • Dissolved oxygen samples were collected into oxygen bottles and fixed by Chlorure Manganium (MgC12) and iodure Kalium in Sodium hydroxide solutions. • Oil samples were collected into cleaned Te11on bottles and added sulfuric acid for preserve. • Heavy metals samples were taken into cleaned Teflon bottles and preserved by superiority chlohydric acid (HCl) 6N. • Nutrient samples were preserved by Mercuric chloride solution. • Plankton and zoobenthos were preserved by formalin 5% or alcohol 70% • Coliform samples were put into cleaned bottles and kept at 4°C in the field thctmally - insulated box (ice box). 14 Fig 2.1. Scheme of sample stations 15 2.5. Analyzing methods : • pH was measured by Palicse standard colorimetry with ceresol red indicator and using "Water Quality Checker" WQC-lAmade in Japan. • Dissolved oxygen (D 0) and Biochemical Oxygen Demand (BOD) determined by Winkler method and using the" Water Quality Checker". • Salinity was t."itrated by silver nitrate solution (Mohr - Knudsen method). 3 2 tt Nutrient contents (N03-, N02-, NI-13, P04 -, Si03 -) total phosphoruswere determined by colorimeter. • Chemical oxygen demand (COD) was measured by oxygenize of permanganate kalium in alkaline medium. • Sulfate was measured by Precipitating BaS04 with BaC12 in hydrochloric medium. • Heavy metals (Cd, Cu, Pb, Hg) were determined by polarograph PAR 364 (USA). (Carried out by Analytical Chemistry Department of Hanoi University). • Organic chlorinated Pesticide Residues in water were determined by following method: - 1 liter of sample was extracted by chloroform (CHCJ3) ,(pesticide analysis grade, 3 times). - Chlorofonn extracts were dried by Na2S04 and cleaned up on Florisil Column, active Carbon and Celitte; then concentrated and remove solvent in rotation evaporator - Concentrate was dissolved by n-hexane and then Pesticide residues was determined by Gas-chromatograph 9A-Shimadzu (at the Technical and Environmental Chemistry Department of Hanoi University); • Oil content was determinated by Partition- Gravimetric Method and c~mtrolled by Infrared Spectrophotometer IR-470 Shimaclzu (at Hanoi University). • Colifmm was detetminccl by Vincent culture method . 2.6 Parauneters 2.6.1. N. the stations of 24 hours: 3 2 Paran1eters of Salinity (9tJo). pH, DO, COD, BODS, N03-, N02-, NH3, P04 -, Si03 -, 2 total phosphorus, S04 - and turbidity, temperature were taken and analyzed in both surfaeial and bottom layers in every two hours at station 4 and four hours at stations 6 and12. Oil and heavy metals were collected at the moments of maximum and minimum tidal heights; phytoplankton and zooplankton - in two layers and every 4 hours; Pesticide and coliform- only in the surface layer at the moments of - max and min tidal heights. Sediment and zoobcnthos were also taken. 16 2.6.2. N. the spatial stations: Parameters were collected and analyzed as: Salinity (o/oo), pH, DO, COD, BODS, 3 2 N03-, NO£, NH3, P04 -, Si03 -, total phosphorus, SO/- and turbidity, temperature and suspended matter and plankton in the two layers, sediment and zoobenthos. The Colifonn samples were collected only in the surface at the stations: 1, 3, S, 8, 9, 13, 14 and 1S. Heavy metals- in the two layers at the stations: 1, 3, 8, 9, 13 and 14. Beside, the bed-form was investigated by Echor sounder (Furuno -400) on S transects. A additional investigation for sea-grass and algae was carried out. 2.6.3. Obtained results. A total of parameters were collected and analyzed as following: 76 Indexes for every parameter: Salinity (o/oo), pH, DO, COD, BODS, N03-, N02-, 3 2 NH3, P04 -, Si03 -, total phosphorus, so:~ turbidity and temperature. 36- oil. 24 - Heavy metals. 11 - Pesticide residues. 20 - Colifom1. 36 - Suspended matter. lS -sediment. 66 - plankton. lS -zoobenthods. S -transects for echor sound bathymetry. 2. 7. Processing results : • Hydrochemical and water quality datum were processed on computer by EXCEL. e Modeling current by wind was carried out on computer by program written in FORTRAN 17 Glaptcr 3. Physical condition of Ha Long area 3.1. Climate. Situated in the monsoon subtropical region, the Ha Long Bay area is influenced by the climate characterized by hot and wet air and the monsoon circulation developing annually into two seasons and, of course, the variation of climatic factors with season and between day and night. TI1ough the Ha Long Bay area is tempered by the climate of open sea, in summer (from May to October), it is hot and wet heavily rainy and in winter (from November to April), it is cold, dry and drizzly. 3.1.1. Air temperature. Air temperature varies with season. In summer, it is over 25 °C average and in Winter, it is below 20 °C average. Annual average temperatupe of the air is 22.7 °C. In January, it is lowest, in range of 14.5-16.5 °C and in July, it is highest, in range of 27.5-29 °C. The highest high temperatupe is 39 °C and the lowest low temperatupe is 4.2 °C. Temperatupe amplitude is 3.5-7 °C in a day and night. 3.1.2. Air humidity. The highest absolute humidity is 38.9 mb and the lowest - 4.1 mb. The mean absolute humidity in Winter is in range of 15-20mb, in Summer-30-32mb and annual-23mb. Annually relative humidity is in range of 82-86%. The highest relative humidity is in March and April, 90% and the lowest - in November and December, 76%. 3.1.3. Rainfall. Annually total rainfall is 1993 mm, approximate to the annually averaged total rainfall in localities in the whole country. The monthly rainfall in rainy season is 293.6 mm and in dry season - 36 mm. The highest rainfall is 463.7 mm in August and the lowest- 18.2 mm in January. 3.1.4. Heat radiation. 2 Annual heat radiation is in range of 11 0-125 kcal/cm • The highest heat radiation is in May and July and the lowest - in January and February, and annual balance - 55-60 2 kcal/cm • 3.1.5. Wind. In winter, northeast wind is predominant with frequency of 25% and mean velocity of 4 m/s, and there arc two periods of northeast wind a month. In summer, east and southeast wind fronts arc predominant with total frequency of over 50% and mean velocity of 3-4 m/s. The wind velocity is sometimes 15-20 m/s but in storms, it can be 18 3.1.6. Storm and tropical depression. Storms and tropical depressions coming from the west Pacific and the East Sea often occur to the area in summer, especially in July, August and September. Wind velocity is always 30-40 m/s and sometimes 50 m/s. In a year, there are 3 or 4 storms and tropical depressions, which are often accompanied by heavy rain, overflowing the area. 3.2. Marine hydrology 3.2.1. Tide. Ha Long bay is constantly influenced by the diurnal tide with a range of 4.6 m. In a month, there arc 2 spring tide periods with the mean level of 3.9 m and 2 neap tide periods with the mean level of 1.9 m. The mean sea level is 2.06 m. 3.2.2. Current. Currents in the 1-Ia Long Bay arc combined from rivers, wind, tides and the bedform of which the tide is always the major factor. Flood tidal current is in the direction of north northwest and contrarily, the ebb tidal current - south-southeast. Inside the Luc inlet, the direction of tidal currents changes by 45° into north-northeast when flood and south southwest when ebb. The velocity of currents is dependent upon phases of a cycle (flood and ebb) and periods of tides (spring and neap) as well as river flow in seasons. In the spring tide, the velocity of currents is 2.5 to 3 times higher than that in the neap tide. Moreover, the velocity of ebb tidal currents is 1.5 to 2 times higher than that of flood tidal currents. In the Bai Chay embayment (Courbct in French), the velocity of current along the Cai L,an navigation channel is 1.34 m/s in ebb tide and 0.89 m/s in flood tide. Toward the Luc inlet, the velocity of ebb tidal currents is 1.05 m/s and that of flood tidal currents - 0.64 m/s. In the Luc inlet, the velocity of ebb tidal currents in the spring tide can be up to 2.0 m/s. In the Ha Long Bay, the velocity of currents in all directions is much lower than that in Courbct. It is 0.1 m/s average and even, outside the Luc inlet, it is 0.19 m/s. Toward the cast and southeast of the Ha Long Bay, the velocity of currents can be over 0.20-0.30 m/s but westward the bay, it is below 0.20 m/s. Because of being larger than Courbet bay, the Ha Long Bay has more influence of wind, one of the facile conditions in water exchange with the sea outside. Wind - generated currents, field of atmospheric pressure and tidal characters are fonnularized by a system of hydrodynamic equations used for shallow waters with pronts 19 of wind at 5 m/s average in probable directions which have the highest frequencies with season. The result is discribcd in the Pig.3.2.2.1, to 3.2.2.8. The result shows that velocity of facial tidal currents are various in places. In the east and southeast of the I-Ia Long Bay, it is often up to 0.20-0.30 m/s but in the west, it is lower. Wind fronts differential in direction often generate local whirlpools in a small scale, and east and west wind fronts often generate tidal currents in the latitudial direction. 3.2.3. Wave Because the Ha Long Bay is a relatively enclosed coastal body of water, it has almost no int1ucnce of waves from the open sea and even no high waves in power wind conditions. Wave fronts, which arc 1.0 m (Ha Long and 0.6 m (Bai Chay) in hight, varies with season. In winter (from November to April), east and northeast waves are predominant with a hight of 0.52 m but in summer (from May to October), south and southeast waves arc predominant with 1.5-2.0 m in hight, especially in August, September and October. Through not having high frequency (12%), the southwest wave is up to 2.5 m in height. Anyway, the time of calm sea or very low waves holds 87.35%. 3.3. Fluvial hydrology. The main rivers inilowing to the I-Ia Long Bay are Troi, Mi, Man and Vu Oai rivers which have hydrologic characters varying with season. Hydrologic characters of the Ha Long Bay arc influenced mainly by rivers in rainy season and tides in dry season because river flow can be decatcs times higher than usual t1ow. Current velocity in the Ha Long Bay in 'ebb tide, for exan1ple, is 1.5-2 times higher than that in ilood tide. In the spring tide in rainy season, the time of iloocl tide is equal to 77% of the time of ebb tide and even in the neap tide, there is the only direct current from Bai Chay to Ha L.ong Bay. 20 _ _j ,---- ·------1 I ,#" ~· ,. / l . - - -_---:)_· --~---· . . ,,.~,,~,~~··-· ---···~·~~~&- .. , ~ -c---r-,A·;·~ ...... «.," ...... "" / i 11: ,. ~· ~ ~ ~· #" I ~· 1· #" _, ' I r_j ..- , ~· ¥ .... .:.-•-..··-~+~~-..~ .• -~ .... - •. • ' ' LJ ; ~- ;: ; I ; :. :· :: : : : :: : : I - - ~· .#' I" I II"~ Ill" ;• a:- -I:"..,_ ~..c.-:--.;;.~~_...-1-. ( r"t-1 ; ·.... 21 .------ Seal~ ... 10 cri'1 '! _I.- ... -lr.-. I 1 '\,.• \t-,·,_ "0· - . \•,t.. ~.":.·.. '- ...... ,.;_ ... _' ...... ,...... "" ...... ,.,,~~~,~~~~.~~~, .. ~.~ ·a··-···--• • -· ~ ~- # ·- .i - .. ,~~'~,~~~~--·--~·-~'-'· • • • ' , ;' ,. ~ ,. ¥ ., ...... ~.~,~~~-~~~~~~-~-·---'''--z -- •• .1' I 1111" II'...... J,.' .... + .,. .:... "'- ..... ' • ...... __ "..,_...t_...c....-L...... ,- ...... "'-.,..'-""·---...... -~-c... • ..:.. .. <1- .,. + ... <.. ... "t. 1t ...._ ... _ ... _ of.- ... ~..,.-""'.~"-"'.. -'#-''~- "'·•-"'-""'""--t..-L-..,...... ,_ ...... -c...... ~ ., .,. .. "- -·- ..... "'-"'- ..... '""-•- ...... _ ...... c.,..._.._~~-~-'"-"· D ::::_.~~·:~~:·.~--~_~ ..!-~,. ,. # ., .... ~ ...... , ... _.,....,.,.""-""-""-""'-..,.-"-.... +-..-.&-..·-~.._~ ... ~~-~--,. ... "' ...... -l::_S ~ ~ \ ·- ·, { , / -· #' 1111"' .....- ...... ~ ...-:.-.=a~.,;~:.:·::~.S:~-.;:..- 1 ·, ." ~ ~ ., ··. ·. ·, ., ··. ... ' ·, ~ ••. J/ ,.... e·.;c-;,:·:;.;-~~ ...:~:s;:...,.":-..;... I· I '~I I '·, ·, ., ... " .. ·., j •'./jc'•/·"-" .....~.,. .... ~..,...,...... --~; J : [l;; ~ ~ : ; r ;~;t,~:~~~.:: ;J-·: l I • "I r--~ li •.:;:-- L I , • . • " I J :~··;..·"-e-r;.._.,_ "'· •. . l______----·------···--······ -- Fig :i.2.2. I ~: ~~; (ff_l ______ I ~·~~~~r ~;C I I I ' f I 4 I 'I I I I r 1 + , 1 r ~ ~ \ I ' I i t "' ~ • I ~ I I I I ~ ~ \ \ "' I I • I ~ "' ! ~ t I l.... ------·------ 22 r------.,------~ 1 l "------.. I Il ______ r- 1 ·------ I (•:•.- I I r-~~ I --.-.-. -.--'. . . . . '":'"1 I [ _____ ·------···----- Fig ~-::!.2.6. 23 ------ Fig3.2.~.7. H;;:ionq S.:Jt,: circub1ion p2tt2rr. (ujriCJ I·JIJ 5 ,r,/f.) -----'I. "'··'-~·+.,;.· .... ·- •. .1- ... 't: .,.. .._ or .._ ., .,. I ., - -1... . .· ·. 1: r.'H ) -~-----· 24 3.4. Hydrochemical characteristics of Halong Bay water. 3.4.1. Water temperature. In the whole bay, it is in range of 28.8°C - 30.2°C (table 3.4.1.): Based on temperature variation, the whole bay can be separated into four parts, (fig 3.4.1.) namely - In the west part, water temperature is below 29°C. - In the northeast part, it is in range of 29°C - 30°C. The part is frequently influenced by run-off, mainly through the Luc inlet. - In the northwest part, shallowest of all, it is in range of 30°C - 31 °C. - In the south part (shallow), it is in range of 30°C - 31 °C. · Based on the temperature space between the two layers, it is possible to recognize two parts: - In Bai Chay embayment and Luc inlet where the stations 1, 2, and 3 are situated, it is 1.5°C bottom layer and the surface one (table 3.4.2.) due to being influenced by run-off. - In the other part where the stations from 4 to 15 are situated, it is 0.1 °C average between the bottom layer and the surface one. It has shown that there is the stability of Ha Long Bay water in raining season. The following arc comments on the temperature based on data from the stations 4, 6 and 12. (Table 3.4.3., figs 3.4.2., 3.4.3., and 3.4.4.) • TI1e day and night amplitude of water temperature of the surface layer is higher than that of the bottom layer. • There is the decrease in temperature amplitude (or increase in stability) toward the sea. • The influence of tides on water temperature is considerable. 3.4.2. Salinity (%o) The salinity of Halong Bay waters is in range of 18.54 - 27.60 o/oo (table 3.4.1. ), increasing toward the sea (fig. 3.4.5.). It is lowest in Bai chay embayment due to running -off. The is remarkable difference of salinity between the two layers based on which the Halong Bay waters can be separated into two parts (table 3.4.2.). - In the Baichay embayment, salinity of the bottom layer is 10 o/oo higher than that of the surface one. - In the other part of the Halong bay, it is only 5 %o higher than that of the surface layer. - So intense stratification of salinity must have been due to the running-off, which frequently influences on coastal waters. Based on data in the table 3.4.3., it is right to make same comments as follows. 25 - The amplitude of salinity of the surface layer is higher than that off the bottom one, especially at the station 4 where there is always river water into the Halong Bay through Luc inlet. - There is intense influence of tides on Salinity (Fig. 3.4.6., 3.4.7. and 3.4.8.). A1 the station 6, instead of the being mixed with the bottom layer, the surface layer in flood tide surges and rises through not deep. The result is that salinity of the surface water layer is not equally increasing with the amplitude of ties (fig. 3.4.7.) and amplitude of salinity is lowest, about 0.92%o (table 3.4.3.). 3.4.3. The pH of water. Based on changes of the pH of 1-Ialong bay water, parts with their own property can be divided as follows (fig. 3.4.9, tab. 3.4.1., 3.4.2). -.In Baichay embayment, the pH of water is low, 7.25 in the surface layer and 7.69 in the bottom layer. -In the other part of the Halong bay, it is 7.89 average in the surface layer and 7.69 in the bottom layer. Difference of pH between the two layers in Baichay is higher than that in the other part. In Baichay embayment pH in the bottom layer is 0.44 higher the surface. In the other part, it is about 0.1. Difference of pH readings from place to place is due to indirect or direct influence of fresh water on waters of the Halong bay. Besides, There is influence of tides on pH as shown in the figures 3.4.1 0., 3.4.11. and 3.4.12. AI. the station 6 (fig. 3.4.11.). However, intense increase in pH of surface water during the time from 1O.OOh till 14.00h is not only related to tides but phytoplankton activities in the clay light as well. It is possible to give some general comments on pi-I as follows: - Halong Bay water is intensely influenced by both water from the Tonkin Gulf due to tides and water from mainland due to run-off, especially raining season. - Hydrochemical characteristics of the Ha Long Bay is function of the interaction between fresh water and sea water, which frequently changes with season, and summarized in the table 3.4.4. - In our cndeav,or to give more detail information on the hydrochemical characteristics, it is necessary to make additional investigations in dry and transitional season. 26 Table 3.4.1. Mean value of hydrochemistry of the Halong Bay Waters in July 1994 Station Temperature (0 C) Salinity (%o) pH 1 29.2 18.54 7.11 2 29.4 21.26 7.54 3 29.8 20.44 7.76 4 29.4 21.51 7.70 5 30.2 23.87 7.90 6 28.8 25.48 7.84 7 30.0 23.24 7.90 8 30.0 26.02 7.86 9 29.9 24.36 7.91 10 30.2 25.76 7.87 11 30.0 25.68 7.91 12 30.1 26.70 7.84 13 29.0 27.60 7.86 14 29.7 24.80 7.90 15 29.8 25.83 7.94 Average 29.7 24.07 7.79 Table 3.4.2. Hydrochemical characteristics of the Halong Bay waters in July 1994 Objects Layer Station 4-15 (1-Ialong) Station 1-3 (Baichay) range average range average Temperature surface 29.0- 30.8 29.8 28.2-29.4 28.7 (OC) bottom 29.0- 30.4 29.9 30.2-30.2 30.2 . Salinity surface 20.62-25.01 22.96 10.51-18.45 15.12 (%o) bottom 25.87-30.()6 27.51 22.43-26.58 25.04 pH surface 7 .R5-7 .92 7.89 6.45-7.78 7.25 bottom 7.83-7.97 7.90 7.56-7.78 7.69 27 Table 3.4.3. One day and night amplitude of hydrochemical characteristics of the Halong Bay waters in July 1994 Object Station layer range average space Temperature 4 surface 28.2-30.0 29.3 1.8 (oC) bottom 28.2-29.8 29.4 1.6 6 surface 27.2-29.0 28.5 1.8 bottom 28.3-29.4 29.0 1.1 12 surface 29.5-30.8 30.1 1.3 bottom 29.9-30.5 30.1 0.6 Salinity 4 surface 11.18-24.75 18.87 13.57 (%o) bottom 21.90-26.99 24.15 5.09 6 surface 24.03-24.95 24.47 0.92 bottom 24.17-29.10 26.48 4.93 12 surface 24.17-28.24 25.76 4.07 bottom 25.92-30.37 27.65 4.45 pH 4 surface 7.32-7.89 7.61 0.57 bottom 7.64-7.89 7.79 0.25 6 surface 7.76-7.86 7.83 0.10 bottom 7.84-7.87 7.84 0.04 12 surface 7.78-7.91 7.83 0.13 bottom 7.83-7.96 7.86 0.13 28 Table 3.4.4. Hydrochemical generali::t..ation of the 1-Ialong Bay water. Objects Range Average Properties Temperature 27.2 -30.8 29.4 High, stability increasing toward the (OC) sea, space of 0.2°C between the bottom and surface layer. Salinity (%o) 11.18- 24.56 Stability increasing toward the sea, 30.37 space of 3.06 between the bottom and the surface layer. pH 7.32- 7.96 7.80 Stability increasing toward the sea, space of 3.06 between the bottom and the surface layer. 29 U("p' .., I I w 0 Fig.3.4.5. Map showing the distribution of salinity (S%o) in the Ha Long Bay · water in July 1994 LEGEND ~<21.) ~ 2~-30 ~ 30-31 ~ lS-22 ~ 22-24 § 24-26 rrrrm26-28 Fig.3.4.2. Change of water temperature at the station 4 on 22-23 July 1994 T (oC) H (m) 31.0 .------, 4 30.0 3 29.0 + 2 28.0 2 7 .o l______l__ ___.JL__.....__ ___.___ ..J._ _ _.__ ___.JL__.....__ ___.___ ..J.______L_ _.J 0 8 10 12 14 18 18 20 22 24 2 8 8 Time (h) -Tidal high! (m) -+- eurlace water ~bottom water Fig.3.4.3. Change of water temperature at the station 6 on 20-21 July 1994 T (oC) H (m) 31.0 .------~ 4 /------·-,, 30.0 ///' ' 3 ______.----.!.----~~~\ / 29.0 2 +___ ~ ''\~~-=--- ~-- 28.0 ~- ~ / + 27.0 '------J'------'------L-----'-----..J.______J 0 10 14 18 22 2 8 10 Time (h) -Tidal hlght (m) -+- aurlece water ~bottom water 31 Fig.3.4.4. Change of water temperature at the station 12 on 24-25 July 1994 T (oC) H (m) 31.0 .------'------, 4 + 30.0 3 29.0 2 28.0 27.0 L------''------L------'-----...l-----.l..------' 0 9 13 17 21 9 Time (h) -Tidal hlght (ml -f- aurtace water ~bottom water Fig.3.4.6. Change of salinity at the station 4 on 22-23 July 1994 H (m) .------,4S% . 30.0 25.0 3 20.0 15.0 2 10.0 5.0 o.oL--~---~~--J---~--~---L-~~--J--~--~-~-~0 8 10 12 14 18 18 20 22 24 2 8 8 Time (h) -Tidal hlght (m) -f- surface water ~bottom water 32 Fig.3.4.7. Change of salinity at the station 6 on 20-21 July 1994 S% . H (m) 30.0 .------.4 29.0 28.0 3 27.0 28.0 25.0 2 24.0 23.0 22.0 21.0 20.0 '------''------'------.....I...------.....______.______J 0 10 14 18 22 2 8 10 Time (h) -Tidal hlght (m) -+-surface water ~bottom water Fig.3.4.8. Change of sanility at the station 12 on 24-25 July 1994 S%. H (m) 3 2.00 ,------, 4 30.00 3 28.00 28.00 2 24.00 22.00 2o.oo'------~------L------~------L-----___J ______~o 9 13 17 21 5 9 Time (h) - Tlda_l hlght (m) -+- surface water ~bottom water 33 Fig.3.4.10. Change of pH at the station 4 on 22-23 July 1994 pH H (m) 8.00 ~------, <4 7.80 3 7.60 2 7.40 + 7.20 7.0 0 L___ __!__ ___JL__ _J.___--.J.__ _.___...... ~.-. _ __JL.__..J..__ _....__ ..L.._ _ __.______, 0 8 10 12 14 18 18 20 22 24 2 8 8 Time (h) -Tidal hlght (m) -!-surface water ~bottom water Fig.3.4.11. Change of pH at the station 6 on 20-21 July 1994 pH H (m) 8.00r------~· 2 7.70 7.80 7.50 L______JL______l ____ -L. ____ _j_ ____ J.______j 0 10 14 18 22 2 8 10 Time (h) ~Tidal hlght (m) -!- aurface water +bottom water 34 Fig. 3.4.12. Changes of pH at the station 12 on 24-25 July 1994 pH H (m) 8.00 r------, 4 •7.80 3 7.80 2 7.70/ 7.60 7.60 '------'-----'----'------'------'------' 0 8 13 17 21 6 9 Time (h) -Tidal hlght (ml -+-surface water ~bottom water ... ·---=-"'-,21'... rig.3.4.9. Map showing the distribution of pH in the I Ia Long Bay water in July 1994 LEGEND [[[0 <7.8 ~ 7.8-7.9 ~7.91 35 3.5. Comments. Being in monsoon subtropical region with hot and wet properties, the Ha Long Bay area is also tempered by the open sea climate and frequently influenced by climate factors (air temperatupe and humidity, atmospheric pressure, heat radiation, rain, wind, etc.) varying with season and between day and night. Flow and current velocity of the main rivers inflowing to the bay and influencing on the bay vary with season. Wave and current characters of the Ha Long Bay are controlled by diurnal tide, wind fronts, bedform and rivers which determine ~ydrochemical characteristics of the Ha Long Bay water. 36 OJ.aptcr 4. Biological characteristics in Halong Bay 4.1. Phytoplankton 4.1.1. Species composition and ecological characteristics. The results of analyzing collected from 12 spatial stations and 3 stations of 24-hr (Fig. 4.1.4) as follow: A total of 178 species, 46 genera belonging to 3 phyla are identified. Percentages of phyla are presented in Fig.4.1.1. It is obvious that Bacillariophyta obtained the highest rate: 78.7% (140 species, 39 genera), then was Pyrrophyta: 20.2% (35 sp., 15 gen.) and the lowest rate belonged to Cyanophyta 1.1% (2 sp., 2 gen.). In 46 genera which distributed in Halong Bay, C'haetoceros was the dominant genus (consist or 30 sp.), then are Coscinodiscus (14), Peridinium (11 ). Nitzschia (1 0), Bactcriastrum (1 0), Rhizosolenia (9). The rest genera consist of 1-6 species. The number of species at the spatial stations arc presented in Fig.4.1.2. In which, station No.9 had the highest number (62 sp.) and then were. the stations: 11, 14, 13,1 O... and the lowest number of species belonged to station No.1 (31 species). Fig.4.1.3 showed that the number or species at the 24-hr stations were not similar. The highest number belongs to station No.6 (110sp.) and the lowest one- No.4 (84 sp.). Most or phytoplankton species in llalong Bay are the tropical and sub-tropical ncar shore species. Some ones such as: Chaetoceros curvisetus, 7halassiolhrix [raucniddii... usually distributed in the places where salinity and temperature changes strongly, were very common in this area. Besides, the indicator species for the warm water 1low in tropical and sub-tropical seas: Chaetoceros diversus and the other for brackish water: Ch. abnmmis also presented in I-I along Bay, although their density were not high. Simultaneously, some fresh water phytoplankton species (1 sp. belonging to Cyanophyta and 2 sp. to Bacillariophyla) also distributed in this area. 4.1.2. Density of phytoplankton cells and their dynamic in 24 hours. In general, the density of phytoplankton cells at the 24-hr stations in Halong Bay is rather high, more lOOOOcells/1. The mean density contours are presented in Fig.4.1.4. It showed that the stations in Cailan port and Luc inlet had low density and ranged from 10000 to 40000 cells/1. The density of cells at the stations (No. II, 12,14) in the east of Halong Bay is higher than the ones (No. 6,8,5,7) in the west. The different in density in the surface and bottom water at the spatial stations arc presented in Fig.4.1.5. In the most or stations the density of bottom water is usually higher than the surface one except stations No.9 and No.5. Dynamic of density at the 24-hr stations are showed in Figs: 4.1.6, 4.1. 7 ,4.1.8. It is obvious that the surface water obtained the maximum density early than the one or bottom water 4 hours or more. 37 Cyanophyta Pyrrophyta 1.1% 20.2% ' / ~ ~/------Bacillariophyta 78.7% Fig 4.1.1 . Percentages of phytoplankton phyla in Halong Bay. 70 60 I 50 (/) Q) "(j Q) l 40 0. .,_(/) 0 30 0 2 20 10 0 Stations Fig 4.1.2. The number of phytoplankton species at the spatial stations. ~- 38 120 100 80 60 40 20 0 4 6 12 Fig 4.1.3. The number of phytoplankton species at the 24-hr stations. 350000 TI I 300000 T ! • Surface water 250000 ::::::: t D Bottom water ~ Qi (,) -1- Ill 200000 I Qi I (,) I .... I 0 150000 .....>- 'iii tI c:: aQ) i 100000 t I I I I I 50000 T 0 N No. of stations Fig 4.1.5 . Density of phytoplankton cells at the spatial stations. 39 ·-·- 120000 T ! i nI I I I j_ I I 100000 I I ! ! I ::::: Vl 80000 ~ QJ ! u en • Surface wat Q) u 60000 '+- 0 0 Bottom wat1 >- Vl c ' Q) 40000 0 t I r-l I 20000 I I 0 + 08 12 04 08 12 04 08 a.m. a.m. p.m. p.m. p.m. a.m. a.m. July July July July July July July 22. 22. 22. 22. 22. 23. 23. Time of sampling Fig 4.1.6. Density of phytoplankton cells at the 24-hr station No. 4 18000 16000 ::::: U) 14000 4i u 12000 U) • Surface wate1 4i 10000 u ..... 0 8000 0 Bottom water > .!:: U) 6000 c: C1l 0 4000 2000 0 > <:::1" <:::1" <:::1" > <:::1" > ::; . en . en . en :J . en :J }"<:j" E -- E -- E -- }"<:j" E - }"<:j" . en ·0 ·0 ·0 . en • 0) E -- C.N C.N C.N E - ci.N E - ·0 N > CD> 0> CD > roN .-- o-:J o-:J :J raN o:; roN 0 -, -, -, N -, 0 0 .- Time of sampling Fig 4.1. 7. Density of phytoplankton cells at the 24-hr station No. 6 300000 - ::::: 250000 _;_ U) 4i (.) 200000 - Vl Surface water C1l • u 150000 - 0 0 Bottom water - I > ·;; 100000 - ~ __ _j c: C1l Q 50000 - 0 E <:::t E <:::t .>en E. >en<:::t E. >;t_'"' .>en c.:;-. c.:;-. ro::;-. ro :; -. ,_-,<:::1" 1..0-,<:::t ,_-,LO en'LO 0 N 0 N 0 N 0 N Time of sampling Fig 4.1.8. Density of phytoplankton cells at the 24-hr station No. 12 41 The high contribution to density of phytoplankton cells in Halong Bay were the species, such as: Chaetoceros curvisetus, 1halassionema nitzschioides, Ceratium furca, 1hallassiothrix frauenfeldii, Ch. pseudocurvisetus, Bacteriastrum varians. B. hyalinum, B. meditcrraneus, Ditylum sol, Cyclotella striata. The most important of which were Ch. curvisetus, Th nitzchioides. The density of Ch. curvisetus obtained from 10000 to 200000 cells per litre and 771. nitzchioides from 1000 to 60000 cells per litre. Their density affected strongly on the whole phytoplankton density in Halong Bay. Although the density of phytoplankton in Halong Bay is rather high abundant but it have not reached to eutrophication level yet. Some species belonging to Pyrrophyta distributed in this area but their density very low. So their effect' on water quality were not worth mentioning. 4. 2. Zooplankton. 4.2.1. Composition and their ecological characteristics. The results of analyzing of 60 samples as follow: A total of 53 ·species were identified. Most of them are tropical coastal species which usually adopt widely and distribute in coastal waters (10-30%.) such as: Paracalanus crasiostrie, Oithoina flumilcra, Acartia pacifica and Evadre nordmani. Some species that usually distribute in coastal waters with rather high salinity (25-30%.), obtained low rate such as: Acrocalanus gilbcr, Calonopia thompsoni, Labidocera dehuncata.. .In the zooplankton composition of Halong Bay have not seen the species: lhdinula vulgaris, Canthocalanus pauper and Neocalanus gracilis. It indicated that the influence of sea-open waters on this area were not strong. Even in the rainy season, the numbers of fresh and brackishwater species as Acartiella sinensis and Mesocyclop leukati were also rare . It showed that the influence of fresh-waters from the continent on this area were weak. This characteristic is different from the species composition characteristis in coastal estuary waters of Namtrieu and Red river. 4.2.2. Distribution of the number of species. Fig. 4.2.1 presented the distribution of number of species. In the most of stations, the number of species in bottom water was higher than in the surface one. Some stations where had the high number of species such as: No. 5,8,9,13,14. The station No.· 13 where closed to coral reefs, had the number of species in bottom water higher than 3 times in the surface one. The composition of zooplankton at the station of 24-hr No. 12 were the thost abundant (see Fig. 4.2.2). 4.2.3. Distribution of density of individuals at the spatial stations. The density of individuals are presented in Figs 4.2.3, 4.2.4. It is obvious that the density of zooplankton individuals in the bottom water at the spatial stations is higher 42 than the surface one many times. In the surface water the lowest value belonged to the stations: No.1 ,2,3 and the highest at station No.5. In the bottom water the highest belonged to station No.9. 4.2.4. The changes of density of individuals in 24 hours. The results of analyzing samples of the 24-hr stations (No. 4,6, 12, are showed in the Figs (4.2.5,4.2.6,4.2.7). It is obvious that in the station No.4, the density of individuals obtained the highest value at 08 a.m. in bottom water (117860 ind./cub.m.) and at 12 a.m.in surface water (1144). In the station No.12, the density obtained the highest value at 5 a.m. in bottom water (147740) at 09 a.m~ in surface one (87769 ind./cub.m). 4.2.5. The effect of water quality on zooplankton community. The studied results of Chan and Kimwong at Tolo Harbour was indicated that the percentage of Cyclopoida group will be increased dramatic if the eutrophication happen. The percentages of zooplankton groups at the station of 24-hr observation (No. 4,6.12) are presented in Figs 4.2.8,4.2.9,4.2.10. Percentage of Cyclopoida obtained the highest value at the station No.6 (31.3% ). This rate in Halong Bay is lower than in Tolo Harbour (66.7%). It is obvious that the water quality of Halong Bay have not been polluted by eutrophication. 4.3. Zoobcnthos. 4.3.1. Biodiversity. 4.3.1.1. Structural diversity. Analyzing result of materials from sub-littoral area of Halong Bay showed on Fig.4.3.1, 85 species belonging to 74 genera, 51 families of 4 principal groups were recorded. Among them 27 species, 23 genera, 13 families of Polychaeta, 34 species, 32 genera, 25 families of Molluscs, 11 species, 8 genera, 6 families of Crustaceans and 11 species, 11 genera, 7 families of Echinodennata (Fig. 4.3.2). There arc two sub-littoral communities in Halong Bay: - Soft bottom community consisting of sampling sites 1-15 and sites 7190 (sampling· in 1971 ). - Hard bottom community, consisting of sites 16-18 on coral reefs (Fig.4.3.3). The family diversity of communities of Halong Bay showed on Fig. 4.3.2. It showed that, species dominance belongs to Molluscs, Polychaeta is second, Crustaceans 43 14 TI i 12 10 r C/) ·c:;Cl) Cl) 8 c. • Surface water .....C/) 0 6 l 0 Bottom water 0 2 n 4 II 2 I ' I I 0 N ("') 1.0 ,...... CXl en 0 ("') <:t 1.0 No. of stations Fig 4 .2.1 . The number of zooplankton species at the spatial stations 40 35 30 C/) ·uCl) 25 Cl) c...... C/) 20 0 0 15 2 10 5 0 4 6 12 No. of stations Fig 4 .2.2. The number of zooplankton species at the 24-hr stations 44 3000 2500 E I I .0 ::l ~ "'C 2000 c: + VI ro I ::l 1500 l ·:;"'C I :0 i c: I ..,_ 1000 ..j_ 0 I I ....> I ·v; i c: Q) 500 0 + I 0 2 3 5 7 8 9 10 11 13 14 15 No. of stations Fig 4 .2.3. Density of zooplankton individuals in the surface water at the spatial stations 250000 T I I E 200000 .0 ::l ~ "'C c: - 150000 VI ro tI ::l ·:;"'C :0 c: 100000 ..,_ ~I 0 > I .... i c:VI i Q) j_ 0 50000 I i 0 2 3 5 7 8 9 10 11 13 14 No. of stations Fig 4 .2.4. Density of zooplankton individuals in the bottom water at the spatial stations 45 120000 -E 100000 .0 :J -:u 'tl c: 80000 (/) "iii • Surface water :J 60000 ·s'tl :a 0 Bottom water j c: .... 0 40000 ....> "iii c: -- - Q) 20000 Q II 0 I D, DU > N > > N > (") N ~v :Jv N :Jv :;v N > . en ~en > ~en ~en > "'Sv E - E - "Sv E - E - "Sv ~en "N ci.N ~en ci.N ci.C'".i ~en roN vN NN vN E - N E - E - ro 0 c. 0 c. co co co 0 0 0 Time of sampling Fig 4 .2.5 . Density of zooplankton individuals in the 24-hr station No. 4 35000 T - 30000 - E .0 :J ~ 25000 - 'tl c: -(/) 20000 - "iii :J ~· Surfac~ :ater I 'tl .---- ~ 15000 --'- Bottom watej c: I! LD nI I I I n I I- I I -1 > ~ > ~ -> ~ > 3 :J :J -:J :J :J 3 l' Fig 4 ·.2.6 Density of zooplankton individuals in the 24-hr station No. 6 46 160000 ,. I I 140000 t -E I .D 120000 j_ ::I I ~ 't:l c: I 100000 T -(/) I i6 • Surface water ::I 80000 ·:.;'t:l +I water :.a i ~Bottom c: 60000 0 t -....> I 'iii 40000 c: t 4l 0 20000 0 09 01 05 01 05 09 a.m. p.m. p.m. a.m. a.m. a.m. July July July July July July 24. 24. 24. 25. 25. 25. Time of sampling Fig 4 .2. 7 Density of zooplankton individuals in the 24-hr station No. 12 Others Harpaticoida _ % 8 9 1.8% Cyclopoida 26.1% ,I I // Calanoida 62.8% Fig 4 .2.8 .• Percentages of zooplankton groups at the 24-hr stations No. 4 47 Others 10.6% Harpaticoida 7.8% Calanoida 49% / Cyclopoida 31.3% Fig 4 .2.9. P~rccntages of zooplankton groups at the 24-hr stations No. 6 Others Cladocera 9.2% 2.8% Harpaticoida 5.8% Cyclopoida 24.1% Calanoida 58.2% Fig 4.2.1 0. P~rcentagcs of zooplankton groups at the 24-hr stations No. 12 48 Fig 4.3.1. Scheme of sites investigate. d cora. . 1s (o) and marine algae 4J 49 Echinodermata 13% Polychaeta 34% 40% Crustacea 13% Fig 4.3.2 ,Percentage of benthic phylla in Halong Bay Echinodermata Polychaeta 13% 26% Crustacea Mollusca 14% 47% Fig 4.3.3 . Percentage of benthic phylla in the soft bottom Echinodermata Polychaeta 19% 19% Crustacea 5% Mollusca 57% Fig 4.3.4 .Percentage of benthic phylla in the hard bottom 50 and Echinodennata are third. Crustaceans are mobile animals so it is difficult to cat and identify them on coral reefs. Basing on Sorensen Index of similarity between sites, four areas are established: Area I consisting of sites 1,2,3. Area II 4,5,7,9,11,12,14 Area III 6,8, 10, 13,15 Area 4 16, 17, 18 Using the diversity Index H' (Shannon Wiener Index) for areas, we have: H' 1 = 0.477, H'2 = 3.915, I-1'3 = 2.029 and 1-1'4 = 3.279. 4.3.1.2. Relative dominance. Relative dominance of zoobcnthic communities is estimated by density of group species (after Sasekumar, 1992). The result of analyzing is showed on Fig.4.3.2, where Molluscs and Polychaeta have the higher density in comparing with crustaceans and echinodennata. Among molluscs, on the soft bottom, dominance belongs to Scaphopo dcs, on hard bottom - Bivalvia. 4.3.1.3. Biomass distribution pattern. Biomass distribution of zoobenthos is showed on Fig. 4.3.3. Biomass at centre of Bay is higher than the around area, here density of individuals is higher 100 ind./sq.m and biomass is higher 2 gr./sq.m in some sites (6 and 7). The density reachs 300-400 ind./sq.m and biomass is 40-144 gr./sq.m. The density and biomass of zoobenthos are index for estimating the level of pollution (Warwick at al., 1987). The studying results showed that central area of 1-Ialong Bay is effected by pollution component, may be, nutrients with high concentration. 4.3.1.4. Biological resource and fishery implements. Among 85 species of recording zoobenthos, many species have high economic value, for example, Mctapcnacopsis stlidulans (belongs to Penaeidae), crabs belong to Portunidac (Portunus pelagicus. Ozaryhdis helleri... ), Molluscs Trochus spp., Turbo, Lunella, Nelita, Area ... They are objects of fishery of people in Halong Bay. Crabs and shrimps are fishing by trammel nets in centre area of Bay. 4.3.2. Corals and coral reefs. Corals and coral reefs distribute in south-east area of Halong Bay (Fig.4.3.1 ), in some bayments of limestone islands. In general, coral reefs have a small range of development, depending on geomorphology and turbidity of marine water. In 1994, we have studied 6 sites in Halong area. 51 4.3.2.1. Species component and richness. Ninety species of hard corals belonging to 35 genera, 12 families were recorded in survey. There are 24 species at Capde, 26-Hangluon, 46- Congua, 55 - Bulau and 77- Vungha. N Trinhnu- only 5-7 species. On family level, higher in number are Faviidae with 32 species, Acroporidae-17 species, Poritidae-1 0 species and on the genus level are Acropora with 12 species, Favia-8 species. 4.3.2.2. Living coral cover. The living coral cover is low in area, ranging from 10- 15% (at Capped) to 30- 50% (at Bull). The dead coral cover is the highest at Trinhnu, reaches 80-90%. In the living coral cover, the highest is a massive form with Favia, Porites ... , which reaches 80%, a branching coral form-only 5-8%. 4.3.2.2.Similarity between sites. The result of similarity between sites computed by Sorensen Index is shown on Table 4.1 and Fig.4.3 .5 Table 4.1. Sorensen Index between sites 1 2 3 4 2 0.35 3 0.28 0.23 4 0.21 0.22 0.36 5 0.35 0.37 0.23 0.26 52 " 6'0 1~0 1 4 Fig.4.3 .5. Dendrogram to show the levels of similarity based on coral species. Basing on Sorensen Index, two areas were established: inner area, consisting of sites 3 and 4, outer- 2, 5 and 1. 4.3.2.4. Biodiversity. Basing on number of species at sites, the Vungha had the highest diversity with If= 0.159, the lowest is Capped- 0.103. It is showed that the environment of Halong Bay has a negative int1uence on corals and coral reef community. 4.4. Marine algae and seagrac;s. A total of 78 species of marine algae were recorded at 9 sites (Fig.4.3.1) on south cast of Halong Bay. Among them the Cyanophyta has 17 species, Rlwdophyt;r21 species, Phaeophyta-19, C'lJ/orophyta-15. On the hard bottom are most of component species, on the soft one IS only Enteromorpha and one species seagrass Cymodocea rotunda/a. Biomass of marine algae raechcs maximum in March and April with dominance of Phacophyta species, such as Sargassum (4060 gr./sq.m), Hydroclathrus (4800 gr./sq.m.) 4.5. Fish. A total of 131 species belonging to 96 genera, 62 families were recorded at Halong Bay. Among them, the pelagic group has 17 species (13%), near bottom group - 41 51 species (31.3%), bottom group- 43 species (32.8%) and coral reef group- 30 species (23%). The list of fish species showed that the fauna of fish has high diversity on genus and family level. Among them, 84 species are the objects of fishing in area for food and decorate aquarium. 4.6. General remark. • The fauna and flora of I-lalong Bay have a high biodiversity with 178 species of phytoplankton, 78 species of marine algae and seagrass, 53 species of zooplankton, 90 species of corals, 85 species of zoobenthos and 131 species of fish . • Many species of fauna and flora of Halong Bay have a high economic value, for example, marine algae - Gracilaria verrucosa, crabs, shrimps, molluscs, fishes and branching corals . . The fishing of a high economic value species have been intensively continued, especially shimps, molluscs and branching corals. The intensive fishing especially by dynamite, push nets causes a negative impact on flora and fauna of Halong Bay. 54 OJaptcr 5. Present status of Halong Bay Water Environment. 5.1. Organic Pollution. 5.1.1. Dissolved oxygen. A part of organic matters discharged into waters will be decomposed by microorganisms. During the process, oxygen is consumed, dissolvedoxygen of waters will be decreased. Based on the decrease in oxygen organic pollution will be assessed. By generalizing data from the investigation made in July 1994, Halong waters can be separated into two parts with their own content of dissolved oxygen (fig. 5.1.1.1 and 5.1.1.2). The first part, it covers Baichay embayment, water along the Baichay beach and Hongai coast, and another in the center (where the stations I, 2, 3. 5. 7, 9, I1 and 14 were situated) in which the dissolved oxygen content of the surface layer is in range of 3.99 - 4.73 ml/1 and 4.39 average and that of the bottom layer is in range. of 3.()4 - 4.69 ml/1 and 4.06 ml/1 average. The other part, the part covers the south and the southeast of the Halong bay where the station 6, 8, I 0, I3 and 15 were situated. The content of dissolved oxygen in the two layers of the part is higher than that of the first part. The content is in range of 5 .(>4 - 5.60 ml/1, on average, 5,24 ml/1 in the surface layer and 4.35 - 5.14 ml/1 and 4.83 ml/1 average in the bottom one. There arc evidences for reducing the content with depth as recorded at the stations shown on the figure 5.I.l.3. and the content is high in the day light and low at night. 5.1.2. Oxygen saturation. Dissolved oxygen in waters is as function of numerous factors of water temperature. salinity, water disturbance, etc. It will be very difficult to detennine the lack of oxygen in water, especially in coastal water if it is based on the dissolved oxygen. Therefore. the oxygen saturation is used here. The spatial distribution of the oxygen saturation of the surface layer is shown in the figure 5 .1.2.1. and that of the bottom one - in the figure 5 .1.2.2. There are three levels of the oxygen saturation, dependent on places in the Halong bay. the lowest level as found in Baychay bay, water along the Baichay beach and Hongai coast and the center is in range of 78 - 90% in the surface layer and 60 - 90% in the bottom layer (fig. 5.1.2.3). The highest level recorded in waters in the south and southeast of the Halong bay is more than 100% and up to 114%. The medium level found in other places is in range of YO - I 00% . 55 The vertical distribution of the oxygen saturation as shown in the .figure 5 .1.2.4. indicate that the oxygen saturation in the surface layer is always higher than that in the bottom one, it is high in the day light and low at night. TI1c problem noticeable is that in Baichay embayment, Water along Baichay beach and 1-Iongai coast which are frequently influenced by river water causing low salinity, both oxygen saturation and dissolved oxygen content should have been higher than that in other places (fig. 5.1.2.3). It is one of the possible evidences for the increase in dissolution of organic matter in water. 5.1.3. Chemical oxygen demand (COD). Spatial distribution of COD is presented in the figure 5.1.3.1 for the surface layer and 5.1.3.2. for the bottom layer. In water of Baichay embayment, Baichay beach and 1-Iongai, especially at the station 12, COD level is highest of the 1-Ialong bay. It is 4.18 mg/1 average and up to 4.99 mg/1. In others adjacent to Catha islands and Bai Tu Long Bay, it is rather low, in range of 2.0- 3.6 mg/1. In the center of the 1-Ialong Bay, COD level in the upper layer is lower than that in the lower layer. In water along the coast, on the contrary, COD level in the upper layer is higher than that in the lower one. It proves that there is concentration of the organic matter from the mainland in the surface layer of coastal waters and accumulation of organic matter in the bottom layer of water in the center (fig. 5.1.3.3.). 5.1.4. Biochemical oxygen demand (BOD). BOD averaged for both the two layers is in range of 0.- I 2.2 mg/1 and its distribution is shown in the figure 5. I .4. In Baichay emb.aymcnt, water along the Baichay beach and Hongai coast and at the station 12, it is above 0.6 mg/1. In the south and southeast of the Halong bay, it is below 0.6 mg/1. AI. the station I, 6 and ·. I 2, it was found higher than 1.0 mg/1. Particularly, at the station 6, it is in range of 0.49 - 4. I 5 mg/1 and on average, 2.2 mg/1. BOD level in I Ialong Bay waters is low except the station 6 in which there is evidence for pollution. 56 - ---~---~--.. _____ l?z.:t··' .I ,,.. Vt -...) ,,.1"'1•_!' 1o~,-::;a Fig 5.1.1.1. Spatial Liistribution of surrJce water Liissolved nxygen Fig 5.1.1.2. Spatial distribution nt bottom wato:r dissnlved oxygen LECEND LEGEND (0.0) ~ <5.0mltl [[[[I] > 5.0 mill - J-4mltl ~ 4-4.Jmltl § >4Jmltl ~·- ''! I t llf ~~·1 \ /1 "=' :'- -, r Ill ..,, I DCTJ='I I I I I I I I I I I ! I I~ ~£·1 -· .. •m 1 /1 ""'='\, ,q t' /I.[":: I O..a£1 I I I I I I I I 1 I I If IQf,~j~' 0 1 2, l k"' loJi. IV IO&~sa' a 1 1 ~ k"' Fig 5.1.3.1. Spatial distribution nf surface water chemical oxygen demand Fig 5 .1.3.2. Spatial distribution of Bottom water chemical oxygen demand LEGEND (C.O.Dl LEGEND (C.O.D) ITITIIII2.40- 3.60 mg/l a 3.60 - 4.30 mg/1 [ill]] 1.80- 3.60 mg/l ~ 3.60- 5,00 mg/l Fig.5.1.1.3.Dissolved oxygen at station 12 on 24-25 July 1994 uD~.O~(~m~l~/1~)------~ 5r------.------~------~----.. - 4 3 - 2 1 I- I oL------L------~------_J·------L------s~- 9 9 13 17 21 Time (h) l::= surface water ~bottom water \ Fig.5.l2.4. Saturation of dissolved oxygen at station 4 on 22-23 July 1994 Satn% DO 1 2 0 .------ 110 ·------100 ' . ------...... (~~------. . ------!._-- ---. __ ...... _ ___ _ 90 80 70 60 ._L 8 10 12 14 18 18 20 22 24 2 4 8 8 Time (h) --surface water ~bottom water I 59 '"''i.,21' I 0\ 0 Fig 5.1.:!.2. Spatial distribution of surface water dissolved oxygen saturation Fig 5.1.2.1. Spatial distributiL>n of bLJttom water oxygen saturation LEGEND D.O ( 0/o satn) LEGEND 0.0 C % Satn.) [[[[] 78 -90 % 90-100% >100%-114% [[[[] 60 - 90 % ~ 90-100% 8 > 100'7c ~ a. 100 no ~ 1- ;.i !- r- ~ eo ~ f- r 70 c ·,-. 6(l ~ so ~ 40 0"' JO 0 20 10 0 '- '-- . 7 11 .. Stlllont 21' 01' ,,. 0 ~· Q 0~ [/ . .. ~ o:j5 O ••• ...J) Qc;: ;_, "0 100 l 80 -~ GO ~ c:i 40 ci 20 0 • B 10 13 15 St~tlions Fig ..5.1.2.3. Dissolved oxygen saturation in various areas of Halong Bay 61 Bai Chay Bay 4.4 4.:1 4.3 4.2 4.1 4.2 "' 4 ~ 4.1 'l 3 9 E • Surface wa1er ci :J.O 0 3.7 ~ 3.9 8nttom W-'lf!f 0 0 11'; c_j 3.8 ~ ----- 3 r, 3.7 3.4 3.6 3 3 3. 5 -IJI""---'+ Fig 5.1.3.3. Various areas of C.O.D in Ha Long Bay waters 62 .. (=:"'J--<.:""c._' --,..,...... ------.:~~ _...J!Q' 21' u!': .,. Fig 5.1.4. Spatial uistrihution of BODS LEGEND [[[[[) < 0,6 mg/l 8 0.6- 1.0 mg/l - 1 -:!,2 mg/l 63 5.2. Oil content in water. Oil content in Ha Long Bay waters is in range of 0.02-0.70 mg/1. Among the 36 samples for oil taken at the 15 stations in the two layers are. + 7 samples (19.4%) with the content below 0.005 mg/1. + 24 samples (66.7%) with the content in range of 0.05 mg/1 up to 0.3 mg/1. + 5 samples (13.9%) with the content in range of 0.3 mg/1 up to 0.7 mg/1. Ha Long Bay waters is polluted in comparison with the Vietnam standard. In most of the samples (80% ), oil contents arc beyond the value 0.05 mg/1· which is the permitted limit for aquaculture. For swimming, all the samples has contents beyond the limit of 0.00 mg/1. Spatial distribution of oil contents is discribcd in the Fig.5.2 and . Fig 5.2.1. Fig 5.:2. Spatial tlistrihution of average •Jil content in water IHIEND ITIIIJI1 < 0,16 mg/1 ~ 0.16 - 0.50 mg/1 64 0.5 0.45 ' 0.4 0.35 0.3 :::: e o.25 0.2 0.15 0.1 0.05 0. V1 0 .: 1 2 4 9 11 12 13 ,_, 8 5 6 7 10 14 15 3 Stations il) ~u 0 -Navigation channels. 0 -OtherS ::I ro 0 Fig. 5.2 .1 Avarage oil content in various areas 5.3. Pesticide residues ~n the Ha Long Bay water. Ha Long Bay, a small coastal body of water relatively enclosed, is frequently supplied with water from the rivers whose basins are forestry, agriculture and reclamation activities are going on increasingly. Pesticide has been used to protect crops and trees for decades of years. Especially, a large amount of pesticide were for agriculture, forestry and prevention of epidemic. In the frame of the project of "Ha Long Bay water environmental quality", II samples for pesticide were taken and analyzed in order to determine pesticide residues in water and to see whether Ha Long Bay water has been polluted by pesticide or not. The result is give in the table 5.3. • Lindane content in the surface water is rather low, 0.0003 mg/l average. The lowest content is 0.0002 mg/l (at the station 8) and the highest content is 0.0005 mg/l (at the station 6, next to the station 8). The is considerable difference among the stations and between the highest and the lowest tides. Lindane content from sample taken in Balat river mouth in the same rainy season (August I994) is 0.00059 mg/l and, of course much higher than that in Halong bay waters. • DDT content in the surface water is very low except the station 3 and 8 at which the content is considerably high, about 0.003 mg/l through much lower than the permitted content. The high content at the station 3 is likely to be related to agriculture and forestry activities in the North and Northeast of l-Ion Gai where are large amount of the pesticide must have been used. It is also explained similarly to the station 8 in relation to Ca Ba forest. A1 the station 4 and I2, DDT content at the moment of highest tide is often higher than that at the moment of the lowest tide. A1 the same time of sam piing, DDT was not found in samples from the Balat river mouth. It proves that there is inlluencc of Pesticide used for forests around the Ha Long Bay. In order to make more detail comments on pesticide residue pollution of the Ha Long Bay water, it is necessary to perfonn the work both in raining and dry season and analyze pesticide residues in water, sediments as well as organisms. 66 Table 5.3. Time (in Pesticide residues No Station hour) and Water Tide (mg/1) date layer (m) Lind an DDT 11 1 6 14 surface 3.6 0.0005 0.0003 c2on) 11 2 6 02 surface 0.6 0.0003 0.0003 c21n) 11 3 4 16 surface 3.8 0.0003 0.0003 c22n) 4 4 04h surface 0.5 0.0003 0.000 C23n) 11 5 12 17 surface 3.5 0.0003 0.0001 (24n) 11 6 12 05 surface 0.9 0.0003 0.0001 c2sn) 11 7 8 13 40' surface 1.9 0.0002 0.003 (2Rn) 11 8 14 08 30' surface 1.8 0.0003 0.0001 (29n) 11 9 9 10 17' surface 1.9 0.0004 0.003 (29n) 11 10 1 07 35' surface 2.0 0.0004 0.0003 (3on) 11 11 3 09 45' surface 2.1 0.0002 0.003 67 5.4. Heavy metals. Heavy metals which are referred to for assessing Ha Long Bay water quality are copper (Cu2+), lead (Pb2+), cadmium (Cd2+) and mercury (I-Ig2+). Their contents are relatively low, particularly for mercury, which often has a content below 0.1 IJ.g/1. The other heavy metals not only have higher contents but more complicated distribution as well. 5.4.1. Copper. Copper content in Ha Long Bay waters is in range of 4.7-57.0 !J.g/1, on average, 11.35 IJ.g/1 and highest of the whole heavy metals . Copper content in the bottom layer of waters is in range of 5.1-57.0 !J.g/1, 16.3 ~tg/1 average, and about 2 or 3 times higher than the content in the surface layer, which is in range of 4.5-10 IJ.g/1 and 6.4 IJ.g/1 average. Distribution of copper in the surface layer of water is represented in. the Fig.5 .4.1-a and in the bottom layer - Fig.5 .4.1-b. In Bai Chay embayment, watersalong the Bai Chay beach and l-Ion Gai coast, and at the stations 12 and 15, copper content is rather high, in range of 6-10 ~tg/1 in the surface layer and 16-35.5 !J.g/1 in the bottom layer. 5.4.2. Lead. Lead content in 1-Ia Long Bay waters is relatively low, about 2.15 IJ.g/1 average. the content in the bottom layer of waters is in range of 1.4-5.0 !J.g/1 and 2. 9 IJ.g/1 average, often 2 times higher than the content in the surface layer, which is only in range of 1.1- 2.1 ~tg/1 and 1.4 ~tg/1 average. Spatial distribution of lead as given in the Fig.5.4.2 (in the bottom layer of water) shows that the content is often high in Bai Chay embayment, wate13'along the Bai Chay beach and l-Ion Gai coast including the station 12. The content in the bottom layer is in range of 2.5-5 IJ.g/1. In other areas of the 1-Ia Long bay, it is below 2.5 IJ.g/1. 5.4.3. Cadmium. Cadmium content in I-I a Long Bay waters is very low, in range of 0.1-0.4 IJ.g/1 and average, 0.2 ~tg/1. The content in the bottom layer of waters is 0.2-0.4 IJ.g/1 and 0.3 ~tg/1 average, 2 or 3 times higher than that in the surface layer where it is only in range of 0.1- 0.2 !J.g/1 ana on average, 0.1 ~tg/1. In the bottom layer of waters of Bai Chay embayment, Bai Chay beach and Hon Gai coast including the station 12, the content of cadmium is high, in range of 0.3-0.4 IJ.g/1 while in other areas of the 1-la Long Bay, it is below 0.3 !J.g/1. 111e spatial distrihution of. cadimium in the bottom water is discribered at the fig. 5.4.3. 68 u~~-:~121' -- I ,•,~· ;:\ ·------l~!~ I I l I I ~ i I '"" I ) /!1• 'I I I I !s I 0'\ \C I06o"ss· wJ- ~~,· Fig 5.4.I.a,Spatial distribution of copper (Cu+2) in surface water Fig 5.4.l.b. Spatial distribution of Copper in Bottom water LEGEND LEGEND ITIJII]< 6 mg/1 6-!0mg/1 ~ ITIIIIIJ<16 mg/1 § 16-35.5 mg/1 I~<,"5 ;' ~ ----~.!-:.·!.•r· I ]I~· -.J 0 ... lk"' Fig 5.4.3. Spatial distribution of Cadimium in the bottom water Fig 5.4.:!. Spatial distrihution of Lead in &>uom water LEGEND LEGEND - < 0,3 mg/1 0,3 -0,4 mg/1. ITiill1J< :!,5 mg/1 § :!.5 - 5.0 mg/1 § 5.4.4. Comment~. TI1e content of the whole heavy metals (Cu, Pb, Cd and Hg) in the Ha Long Bay waters is low and lower than the fermitted limit and the Ha Long Bay wateit has, of course, not been polluted by heavy metals. Their content in the bottom layer of water is often 2 or 3 times higher than that in the surface layer. More over, the content is high in the areas of Bai Chay embayment, Bai Chay beach and l-Ion Gai coast, including the station 12. In reason for this, we can say, as it were, bottom sediment is the major source of heavy metals. 71 5.5. Nutrients. 3 Nutrients from the investigation made in July 1994 include phosphate (P04 ·), total 2 phosphorus (!J.g), ammonia (NI-13), nitrite (N02 -), nitrate (N03 -) and silicate (Si03 -) They were investigated in the same way as hydrochemical objects (in the part 3.4.) and results are summarized in the table 5.5.1 and 5.5.2. 5.5 .1. Phosphate and total phosphor1.1s In the northwest part of the Ha Long Bay, the content of phosphate and total phosphor-us: is higher than that in the centre and the northeast part of the Ha Long Bay (table 5.5.1 and Fig.5.5.1). Fresh water from the mainland in to Bai Chay embayment and wastes from populated areas surrounding are reasons for this. The northwest coast of the Ha Long Bay is where there are numerous tourists and a tourist harbour with hundreds of tourist boats in operation. Most of tourists often have visits to Dau Go Cave (next to the station 6). In the area of the station 6, the content of nutrients is high. The content of total phosphorus , for example, is 14 j.lg/1 and highest of the Ha Long Bay. The contents of total phosphorus in the two layer are similar hut the content of phosphate in the surface water is always higher than that in the bottom water and it changes frequently (Fig. 5.5.5, 5.5.6 and 5.5.7). 5.5.2. Ammonia, nitrite, nitrate and silicate. Data in the table 5.5.2 show that in Bai Chay embayment (stations 1, 2 and 3), the contents of ammonia and nitrite are higher than those in the centre (stations 14 to 15) of the Ha Long Bay. Rapid transfonnation of NH3 => N02- => N03- of fresh water charged into the Bai Chay embayment ceates an area with high content of No1- as found in I ,uc inlet (Fig.5.5.2). It is obvious that fresh water takes an important part in charging nutrients with nitrogen into the I-Ia Long Bay. In the area of the station 6, content of ammonia, especially in the bottom water, nitrite and nitrate are relatively high (table 5.5.2, Fig.5.5.8 and 5.5.10). So high contents are due to tourists themselves who littered rubbish when coming to visit the Dau Go Cave. The distribution of silicate in the 1-la Long Bay is rather complicated though there is no remarkable difference in content among the stations. In some places, it is below 800 1-L g/1. This is due to activities of phytoplanktons, especially Diatoms (Fig.5.5.12). In most t)f the stations, the content of nutrients in the surface water is higher than that in the bottom water (table 5.5.2). Results obtained from the one day and night stations show that the content of nutrients varies complicately and depending upon factors (Figs.5.5.9 to 5.5.11, Figs 5.5.13 to 5.5.21). 72 5.5.3. Prclimilary comments. It is possible to make some prelimilary comments based on the results as represented. • Distribution of nutrients. The content of nutrients in the surface water is higher than that in the bottom one. It is quite contrary to the distribution which occurs to the open sea and ocean. High content of nutrients was found in the area of Luc inlet into which fresh water is frequently charged and in the northwest coast disturbed by tourism operations. Complicated changes in the content of nutrients are as a result of influence of factors such as fresh water from mainland, tides, wastes and plankton activities. • Nutrient sources. Two sources which provide the Ha Long Bay water with nutrients arc from the mainland owing to fresh water and on the spot due to tourism operations. • Water quality. TI1ere is no evidence for eutrophication in the Ha Long Bay water as based on data from the investigation. • We can say, as it were, the lla Long Bay waters has not been polluted in form of nutrients. In order to have a full assessment of the Ha Long Bay water quality in form of nutrients, it is necessary to add investigations both in dry and transitional seasons. AI. that time, sources of nutrients and the amount of nutrients extracted by organisms in the Ha L..ong Bay water should be paid close attention. Q z UJ Ci J ~ 73 Table 5.5 .1. Average content in (J..lg/1) of nutriens in the Ha Long Bay waters in July 1994. No - NO- Si0 -2 Station Po4-3 LP NI--13 2 3 3 (~LgP/1) (~LgP/1) (~LgN/1) (JlgN/1) (llgN/1) (JlgSi/1) ] 3.8 11.7 24.4 1.4 7.3 950 ') "- 5.0 11.8 19.0 1.6 7.8 820 3 4.4 12.7 20.4 1.5 7.0 850 4 4.7 11.9 19.8 2.6 13.0 540 5 4.0 13.1 17.0 1.7 6.8 880 6 4.2 14.4 18.9 4.7 9.4 460 7 4.0 14.8 18.4 1.7 8.0 1010 8 3.5 8.6 22.4 1.4 8.0 840 9 3.8 14.2 17.0 1.7 8.0 980 10 3.8 9.4 20.4 1.2 7.5 870 11 3.8 7.2 19.0 1.8 9.1 820 12 5.0 9.8 18.6 1.6 9.5 600 13 4.0 10.6 14.3 1.1 6.4 980 14 3.4 11.6 20.4 1.3 8.7 770 15 3.4 7.4 23.8 1.4 8.6 820 Average 4.0 11.3 19.6 1.8 8.3 810 Table 5.5 .2. Content (~Lg/1). of nutrients in layers of the Ha Long Bay Water in July 1994. Stations 4 to 15 (Ha long) Nutrients Layer Stations 1 to 3 (Bai Chay) Range Average Range Average P04-3 s 4.0- 5.0 4.4 4.8- 5.6 5.3 b 2.8 - 3.8 3.1 2.9-4.3 3.5 LP s 7.2 -15.0 10.8 11.5-12.3 12.0 b 6.8 -15.8 10.7 11.3-13.1 12.2 NI-h s 16.3-29.8 24.4 25.8- 31.2 28.0 b 12.2-17.7 13.9 10.9- 7.7 14.5 NO-,- s 1.1-1.9 1.6 1.7-1.8 1.8 b 1.0-1.7 1.3 1.2- 1.3 1.2 N01- s 7.0-10.8 9.1 9.3- 0.8 10.0 b 4.5-7.4 6.6 4.7-4.9 4.8 Si01-2 s 940-1200 1070 970-1070 1010 b 6oo-~no 710 670-830 730 Legend: s- surface layer ; b- bottom layer; L P- Total phosphorus 74 Fig.5.5.2. Change of total phosphorous content at station 4 on 22-23 July 1994 Total P!f.gll) ______H_(m-,) 16.0 ,---_...!~------4 + 14.0 3 12.0 1o.o 2 8.0 6.0 4.oL__ _L__ L_ _ _l___ L_ __ _l ____L_ __ _L ____ L_ __ _L ____ ~-~--~o 8 10 12 14 16 18 20 22 24 2 4 6 8 Time (h) -Tidal hlght (m) -+--surface water ~ bottom water Fig.5.5.3. Change of total phosphorous content at station 6 on 20-21 July 1994 Total PfiJ.9P!I) H (m) 20.0.---~~------~4 18.0 3 16.0 ------~-~ 2 14.0 + 12.0 + 10.0L______L_ ____ ~-----~------i_------~------'0 10 14 18 22 2 6 10 Time (h) -Tidal hlght (m) -+--surface water ~bottom water 75 Fig.5.5.4. Change of total phosphorous content at station 12 on 24-25 July 1994 Total P !,).l.gP/1) H (m) 13.0.-----~------.• 12.0 3 11.0 2 10.0 9.0 8.0~------~~------+------~------~------+------~o 9 13 17 21 5 9 Time (h) -Tidal high! (m) -1-- surface water ~bottom water Fig.5.5.5. Change of phosphate content at station 4 on 22-23 July 1994 Phosphate lJ.tgP/1) H (m) 5.6.------~------·· + / "" ~""' 3 j\x}- ~-~~d / /'~ ±~_, 2 ' . •. '" - ''.----.------/ ~'- ~ 4.1 ~ ",, I • , --- 3. 6 1'------L..----'- _L___I ______l ____L_ __ __L ____ L.... __ ___L______L______L__ ---- 0 8 10 12 14 18 18 20 22 24 2 4 6 8 Time (h) -Tidal hlght (m) -1-- surface water ~bottom water 76 Fig.5.5.6. Change of phosphate content at station 6 on 20-21 July 1994 Phosphete Y..,gP/1) H (m) 10.0~------~------·4 8.0 3 6.0 + 4.0 ~ ... 2.0 0.0 L._.______.______L______[ ______]_ ____ ------·- 0 10 14 18 22 2 6 10 Time (h) -Tidal hlght {m) + aurlace water ~bottom water Fig.5.5.7. Change of phosphate content at station 12 on 24-25 July 1994 Phosphate ~gP/1) H (m) 8.0r-----~------4 --... --- 3 + 2 4.5 4.0 1-----+------1------+------+------1------0 9 13 17 21 5 9 Time (h) -Tidal hlght {m) + aurtace water ~bottom water 77 Fig.5.5.8. Map showing the distribution of No3- (llgN/1) in the Ha Long Bay water in July 1994 LEGEND ~ <7 E§ 7-9 [ill]]] 9- II Ia II - 13 ~ 7-. II mm 9.4 78 Fig.5.5.9. Change of ammonia content at station 4 on 22-23 July 1994 Ammonia {.ugN/1) H (m) 25.0.-----~~-----+------,4 24.0 23.0 3 22.0 21.0 20.0 2 19.0 18.0 17.0 18.0 15.0~--~----~--~----~--~----~--~----~---L----~--~--~o 8 10 12 14 18 18 20 22 24 2 4 6 8 Time (h) -Tidal hlght (m) -+-surface water ~bottom water Fig.5.5.10. Change of ammonia content at station 6 on 20-21 July 1994 Ammonia Y-LgN/1) H (m) 30.0.-----~~------.4 28.0 26.0 3 24.0 22.0 / 2 _____L______------0 10 14 18 22 2 8 10 Time (h) -Tidal hlght (m) -+-surface water ~bottom water 79 Fig.5.5.11. Change of ammonia content at station 12 on 24-25 July 1994 Ammonia Y-wN/1) H (m) 23.0.-----~~------,4 + 22.0 21.0 + 3 20.0 19.0 18.0 17.0 16.0 + /" 15.0 ----- 14.0~------+------+------+------+------+------40 9 13 17 21 6 9 Time (h) -Tidal high! (m) -l- surface water ~bottom water Fig.5.5.13. Change of nitrite content at station 4 on 22-23 July 1994 Nit rite £Ag N/1) H (m) 4.0.------.4 3 2 0.0 , ___...._L_ ____ ._L._ __ ...... J. ___ _j ____j ___L ___ _j _____ j_ ____L_____j ___ _L_ ---. 0 8 10 12 14 16 16 20 22 24 2 4 6 8 Time (h) -Tidal hlght (m) + surface water ~bottom water 80 Fig.5.5.14. Change of nitrite content at station 6 on 20-21 July 1994 Nitrite (julN!i) H (m) a.or---~~------~4 5.5 3 5.0 2 4.5 + 4.0 c...__------'------..l. ______j ______] ______·- L.-... . ··- 0 10 14 18 22 2 6 10 Time (h) -Tidal hlght (m) +surface water ~bottom water Fig.5.5.15. Change of nitrite content at station 12 on 24-25 July 1994 Nitrite \f.LgN/1) H (m) 2.5 ,------·------4 + 2 3 1.5 - 2 '------~-- 0.5 0 J------J------1------t-- 0 9 13 17 21 5 9 Time (h) I -Tidal hlght (m) +surface water ~bottom water I 81 Fig.5.5.16. Change of nitrate content at station 4 on 22-23 July 1994 Nitrate ~N/1) H (m) 16.0.-----~------.4 15.0 3 14.0 13.0 2 12.0 11.0 1o.oL----L----L---~----~--~----~--~----~--~----~---_J--~o 6 10 12 14 16 18 20 22 24 2 4 6 8 Time (h) -Tidal hlght (m) -1- surface water ~bottom water Fig.5.5.17. Change of nitrate content at station 6 on 20-21 July 1994 Nitrate (J.l.gN/1) H (m) ------4 13.0 t-- + 3 ·-+-- ,J ···------+------+------I + 9.0..=-----. \ ------. ~ -. ----~- I 7.0 k _j______...... [___ 5.0 L______.______0 10 14 18 22 2 8 10 Time (h) -Tidal hlght (m) -1- aurlace waler ~-bottom water 82 Fig.5.5.18. Change of nitrate content at station 12 on 24-25 July 1994 N_lt_r_at_e_vw~_N_t_O ______~------H __ (m ) 12.0 .- 1 4 11.5 + 11.0 3 10.5 + 10.0 2 9.5 9.0 6.5 6.0 i-----t----1----t-----+------j 0 9 13 17 21 5 9 Time (h) --Tidal high! (m) +surface water ~-bottom water Fig.5.5.19. Change of silicate content at station 4 on 22-23 July 1994 Silicate {I.LgSI/1) H (m) 700~--~------/'------~-.-----~------+------.4 Boo' / '"'-- +_..------....__1=~---- 500 L __~t -+-·· ~ '--._~'''}~ 3 400 2 300 200 100 -~~ 0 L___ _L______l _ ___j_ __,_ ) ____ ----'-----.L_----'-----..L____L_ _ __.__---'o 6 10 12 14 16 16 20 22 24 2 4 6 6 Time (h) I -Tidal high! (m) -+-surface water ~bottom wa.:J 83 Fig.5.5.20. Change of silicate content at station 6 on 20-21 July 1994 Silicate (p.gSi!l) H (m) aoo.-----~------,4 550 + ------.... 3 //------. 500 + + 450 400 350 300L______L______l ____L ______l______L ------0 10 14 18 22 2 6 10 Time (h) I -Tidal high! (m) -+-surface water ~bottom water J Fig.5.5.21. Change of silicate content at station 12 on 24-25 July 1994 Silicate {p.gSI/1) H (m) 750 r---- 4 700 3 650 600 2 550 ----;z______- 500 ;/ + 450 - 4001------+------~ 0 9 13 17 21 5 9 Time (h) I Tidal -high! (m) --!-surface water ~bottom water] 84 2 5.6. Sulphate content (S04 -). Sulphate is a common anion in water and it's content varies from several to thousands of milligrams per litre. In water from the Red River, Da or Luc Nam systems, the sulphate content is in range of 0.5-55 mg/l. Yet, in sea water, it is higher. In sea water which has salinity of 35%o, the sulphate content can be up to 2. 7 g/1. Sulphate, one of the factors causing pollution of water, is inherent in wastes from mining and cellulose plants. When it is beyond the content of 250 mg/k:g which is the pennitted limit for domestic water, it has an ability of cathartic. In the 1-Ia Long Bay waters, sulphate content is rather high, in range of 1.7-3.0 g/l (1.7- 3.0 ppt). Particurlarly, along the Cai Dam, Bai Chay and Hon Gai coast, it is relatively high, in range of 2.0-3.0 g/l (Fig.5.6). The Fig.5.6. shows that the increase in sulphate content can be related to wastes from mining for coal. What is more, areas of reclamation and production of bricks in Hoanh l3o are also reasons for this. ~~· CAT llA 10&"!-a' l km Fig 5.6. Spatial distrioution of sulfate content ~ 1,6-1,70mg/l ~ 1.70-:!,0mg/1 ~ 2,0- J.Omg/1 85 5.7. Microorganisms (Escherichia coli) Escherichia coli is use as a biological indicator for assessing thec.ontamination of the coastal waters. In Vietnam, Escherichia coli indicator has been used mainly for runing water, drinks and liquid food and not use commonly for natural waters with provisional standard promulgated in 1993. E. coli levels in 20 samples, among which are 14 samples in the surface layer and 6- in the bottom layer, are as follows: Table 5. Zl. E. coli levels in the surface layer - Common levels. Maximum 5,700 Minimum 9 Mean 562 - Levels at the moment ol the highest tide. Maximum 5, 700 Minimum 9 Mean 954 - Levels at the moment of the lowest tide. Maximum 186 Minimum 9 Mean 35 Table-'- 7.2. E. coli levels in the bottom layer. - Common level~·. Maximum 420 Minimum 30 Mean R4 - Levels the moment of the highest tide. Maximum 5,700 Minimum 9 Mean 954 -Levels a/the moment of the lowest tide. Maximum 1R6 .Minimum 9 Mean 35 Commom levels in the two layers Maximum 5,700 Minimum 9 Mean 418 86 The result shows that E. coli levels in the surface layer of water are often higher than those in the bottom layer and they are below the permitted limit of of the Vietnam standard. The highest level of E. coli is 5,700 the lowest is 9 and the mean is 1466 as found at the station 4 which is frequently in fluenced by waste water from urban and-tourism operations. E. coli level here is beyond the permitted limit of Vietnam's current standard. Table 5. ZJ. E. coli levels in the surface layer of Ha Long Bay Waters. No Station Sea level E. coli levels Coliform Fecal coliform 1 4 highest 4600 1100 2 4 lowest 93 09 3 12 highest 09 0 4 12 lowest 09 0 5 6 highest 09 09 6 6 lowest 93 93 7 13 mean 43 23 8 8 mean 2400 93 9 15 mean 150 23 10 14 mean 09 0 11 9 mean 460 93 12 5 mean 240 15 13 1 mean 1100 93 14 3 mean 4600 460 Table 5.7.2. ·; E. coli levels in the bottom layer of Ha Long Bay Waters. No Station Sea level E. coli levels Colifmm Fecal coliform 1 4 highest 93 23 2 4 lowest 15 15 3 12 highest- 23 04 4 12 lowest 240 93 5 6 highest 210 210 6 6 lowest 43 43 87 5.8. Transparency and light penetration. • The transparency can be determined by making visual observation on Secchi disc. The variation of Secchi disc depth is presented in Fig. 5.8.1, 5.8.2. In general, four districts having Secchi disc depth in difference that demonstrates the transparent range was distinguished. Bai Chay embayment waters had the lowest Secchi disc depth of less than 1 m. The poor transparency results from the turbid discharges from rivers as well as streams in adjacent mining area. The waters the district around Tuan Chau island had Secchi disc depth from 1.0 to 1.4 m. The worst situation is due to effective discharges from Western river system flowing in to the Bay and small depth of waters (less than 2.0 m). Secchi disc depth from 1.4- 3.0 m was recorded in the centre composing of most of Ha Long Bay waters. The better transparency was observed in the waters bordering Bai Tu Long Bay with the Secchi disc depth was more than 3 m. This is because the waters area rather deep (more than 5 m) and turbid discharge effect from rivers is hardly significant. • Turbidity and suspended solids. In the rainy season in 1994, turbidity in Ha Long Bay waters ranged from 30 to R7 mg/l and varied in districts. The high value of turbidity (more than 70 mg/l) was recorded in the waters around Tuan Chau island. The Bai Chay embayment waters had the value of 50 - 70 mg/l and another ones had the value of 30 - 50 mg/l. The difference in turbidity gave a note of in11ucncy of material supply from main land corresponding with the transparent variation (Fig.5 .€.3 ). Suspended solids had higher level in Bai Chay embayment waters and Hon Mot navigation channel ranging from 40 to 60 mg/l. In the other waters, suspended solid content was from 20 to 40 mg/l, the lowest level (less than 30 mg/l) was found in the centre of the Bay (Fig.5.8.4). In general, there are a correspondence between turbidity and suspended solids. In the waters, the greater turbidity, the higher content of suspended solids. However, a particular situation was found in l-Ion Mot navigation channel and in the centre of the Bay. In the channel, turbidity was not greater than that in adjacent waters hut suspended solid content was higher than that in the same waters and vice versa in the centre. This situation can he explained by phy~oplankton present. Turbidity and suspended solids in waters or I Ia Long Bay arc affected by run -off from rivers and in. a part by activities of coal mining in Hong Gai. Turbidity alteration in 24 hours is controlled by tidal range (Fig.5 .. ·.1 ). Comparing to the standard of turbidity in swimming waters in Vietnam (less than 25 mg/1), turbidity in the waters is high in rainy season particularly in Bai Chay embayment due to coal mining activities and reclamation in northern areas. 88 F'lg.5.o ~ I Sec h · at the st.at· c I disc depth 1ons in J 1 "" '""" •• u y 1994 0 - btJymanl luc ~nler 2 D e p t h 4 - I n m e t 6 r e 8 1 2 Fig5$" . . . -· Sp:Jlral distrihut·"'" nf a vcragc. Sccchi drsc. .rn July I !)94 LHiEND ~ 89 :'.;'"Sl!' ~/·1 ..:·:.:!·'i~.· I !-'-~ j', I: '" - ~ ) ,.~I "'0 106~59' Fig 5.8.4. Spatial distribution of avt:rage suspended matter in July 1994 Fig 5.8.3. Spatial distribution of verrage turbidity in July 1994 LEGEND LEGEND illiiiiJ20- 40 mg/1 g 40 - 50 mg/1 >50 mg/1 ~ illiiii]] 30-50mgfl ~ 50-70m9/l ~ >70mg/l " Fig.5.8 5. Turbidity change in 24 hours at Luc inlet (station 4} Turbldlty(mg/1) 110.------ 100 90 80 70 ~ 60 // 50 _,/"'',,' / ~--~----' 40 '-,/ 30 20 10 0 2 3 4 5 6 7 8 9 10 11 12 13 Observed points of time -surface layer --•- bottom 18Y:] 91 5.9. Current status of garbage in area. Up till now, kinds of garbage have been discharged and dumped without disposition and any way of treatment. Places concentrating garbage are distributed on the coast from Bai Chay swimmimg beaches to l-Ion Gai town, particularly on the 1-Ia Long market and the eastern coast of Bai Chay embayment. Kinds of garbage have been discharged into waters near the coast for construction flats in these places. Several islands being attractive tourist spots are sites of garbage accumulation. Besides these, garbage moves everywhere on water surface. There are many kinds of garbage discharged such as: old papers, carton, cans, empty bottles, plastic containers, pieces of wood, pieces of tree coming from river flows or from mangroves exploited around the area. All of them have been discharged and dumped by man on the coast or by currents on water surface. Garbage discharges are from industrial activities such as: from factories of processing coal, beer, making brick, ship building being on Bai Chay embayment coast, from activities of ports and coal mining. They are contributed by exploiting· and cutting upstream forests and mangroves and reclamation in the northern area of Bai Chay embayment. A considered source of garbage results from everyday life activities and tourist service activities. Kinds from these are found everywhere: on swimming beaches, on water surface, around hotels, restaurants, habours and in attractive islands. With current status of garbage in Ha Long Bay area the waters of Bai Chay embayment and 1-Ia Long Bay can be polluted in the coming time. 92 Chapter 6. Assessment of Ha Long Bay water quality. Based on data from the in vcstigation made in July 1994 and data before, it is reasonable to generalize the problem as follows. 6.1. Pollutants. 1-Ia Long Bay waters arc in pollution by the followsing: 6.1.1. Oil and products from oil. In the 1-Ia Long Bay, oil and products from oil are main pollutants, which should be paid close attention to. Though different from each other, Ha Long Bay waters are polluted. A<; many as 80% of the total of 36 samples taken in July 1994 have oil contents up to 0.05 mg/1. Especially, in the navigation channel to Hon Gai and B12 port, the oil content is considerably higher than that mentioned. 6.1.2. Organic matter. The evidence that there arc frcqently Nitrit (N02-) and decrease in content of dissolved oxygen and oxygen saturation in coastal waters of Bai Chay bay, Bai Chay beach and Bon Oai coast, increasing COD beyond 4 mg/1 at some moments of obsrvation shows that Ha Long Bay arc polluted through in a low level and small scale. 6.1.3. Wa<;tes. Wastes, in which we should take interest, arc changed into the bay without treatment. Along the coast from lion Oai to Bai Chay, they can be seen floating and in littered crowds. It is possible that they have not had serious influence on water environment but they should be referred to. 6.1.4. Suspension and turbidity. Suspension ilil-la Long bay waters is mainly from suspended sediments. Transparency of I Ia Long Bay waters higher than that of adjacent sea waters. In watcli of Baichay bay, baichay beach and l-Ion Gai coast and the area of the Dau Oo cave. However, suspension is often over 50 mg/1 and beyond the pcnnitcd limmit. 6.1.5. Sulphate (Sq~.2- ). Sulphate- content in the Ha Long bay waters is relatively high, in range of 1.7 - 3.0 g/1, particularly 2.0- 3.0 g/1 as found in West Baichay bay and l-Ion Gai coast which arc ncar the mining area (Ha Tu and 1-Ia Lam) as well as in Cai Darn coast. This content is beyond the pcnnittccl limit for drinking and domestic life. 6.1.6. E.coli Results from the investigation in July I t)t)4 show that colifonn levels in waters of Baichay hay, Cua Luc and at the station X (ncar the Dau Clo cave) arc over I ,000/1 OOml, higher than those in other areas of the Ha Long bay. With such an evidence, we can say I Ialong bay waters arc polluted by fecal materials though in a low level and small scale. Ha Long Bay waters arc polluted. Besides the pollution by sulphate (so42-), organic waters. suspension and fecal materials in a low level and small scale, the pollution by oil is in the highest level. t)J 6.2. Pollutant sources to Ha Long Bay waters. Based on data from the investigation in July 1994, data on physical conditions and socio - economic activities of Ha Long city, it is possible to define pollutant sources to Ha Long Bay waters as follows. 6.2.1. Ports and habours. Besides a group of large ports as l-Ion Gai coal port, B12 oil port and Cai Lan commercial port, there are harbours for fishing, passengers and tourists, Bai Chay ferry and car stations scattered along the coast of the Ha Long Bay. Their activities can cause sensitively oil, coal dust or rubbish pollution of waters nearby of the Ha Long Bay. 6.6.2. Marine transport operations. All kinds of mean of transportation in operation in the Ha Long Bay are ships for oil, cargo and coal transport, bigger and smaller boats for fishing, tourism, market and passengers. For fishing alone, the number of boats which are in frequent operation in the Ha Long Bay and adjacent waters is about 3,000. Marine transport is a notable source of oil waste, rubbish, including empty bottles to the bay. 6.6.2. Tourism. Tourism is one of the economic sectors on the way of development, especially in the future. The Ha Long Tourism possesses a system of hotels and restaurants by the Bai Chay and Hon Gai coast, swimming beaches, beauty spots, fanciful sights and a larger number of tourist boats. It is easy for waters to be polluted by microorganisms (E. coli) from rubbish and wastes clue to tourism operations. 6.2.4. Urban life. Besides the Ha Long city population of 120,000 persons, nummerous visitors frequent hotels, restaurants, markets, clubs, harbours, etc. Though not dense, the population and visitors provide the Ha Long Bay with a lot of wastes which become the main source of pollutants. 94 6.3. Preliminary assessment of the impacts of the pollution on the health of dwellers and ecosystems. The results, as given in the two parts above contaminants (6.1. and 6.2.), show that which have more abilities the cause pollution are oil waters, organic matter from rubbish, suspensions, sulphate and E. coli. 6.3.1. Oil and products from oil may have certain influence on the health of dwellers visitors on the way of respiration and digestion. For those who like swimming, their eyes are easy to be influenced by suspensions and their digestion - by E. coli. 6.3.2. There is influence ofpollutions on flora and fauna of the Ha Long Bay. Different pollutants, however, affect differently communities. Planktons, for example, which often migrate owing to currents, may be affected by oil and products from oil and changes of salinity for which the density of the planktons in the surface layer is always low than that in the bottom layer. In waters along the coast and of the center, benthos may be affected most by industrial and domestic wastes (not including oil) which cause the increase in the number of some species belonging to Polychaeta and Scaphopoda. Corals and coral reef in the 1-Ia Long Bay are influenced by suspensions which can cause the death of corals after losing zooxanthellae when deposited on the face of reefs. The photosynthesis of zooxanthellae must have been affected intensely by high turbidity for which the cover and species composition of corals increase toward the sea. Evidences for environment impacts on algae and fish have not been focused on these objects. 95 6.4. Ha Long Bay water environment in the future. From the results obtained in the 1994 and before in association with data on planning for development of Ha Long City, it is possible to predict the state of pollution of Ha Long Bay water environment in the future, as follows. 6.4.1. Oil pollution and accidents. This is the most important problem that should be solved prior. The plan to enlarge and upgrade capacities of the group of the Cai Lan commercial port (up to 20 mil. ton. of cargo a year), the B12 oil port (2-3 mil. ton of oil a year), Hon Gai coastal port and the 1-la Long Ship building yard and feasibility to intensify marine transport operations in area will cause pollution at the higher level and oil accidents with higher probabilities. Oil pollution with higher content, especially oil spills if possible, will do harm not only to landscapes but visitors as well. Beside these, diseases will develop, marine organisms can be dead, ecosystem will be deteriorated and marine resources, of couse, will be degraded. 6.4.2. The plan to develop economic base in the basin of the river ·flowing into Baichay embayment in which there will be a cement plant with the capacity of 3 mil. ton. a year, 3 brick plants with total capacity of 50 mil. bricks a year, new reclamation with an area of 1,200 ha and promotion of processing and mining for coal will be a cause to enrich suspensions and sulphate in the water environment. Besides the intensification of siltation in navigation channels and the degradation of water quality, especially in swimming beaches, it will have negative affects on marine ecosystems sensitive to environment changes such as coral reefs, algae and sea grass due to the reduction of water transparency. 6.4.3. In the master plan Lo develop J-/a Long City till the year 2010, pollution will be as many as 7 ,000,000, 5 times higher than the present number and tourism will be invested greatly in order to upgrade servicing capabilities and the number of tourists. Kinds of the wastes, therefore, especially fecal materials and waste water, will be enriched. These will be not only do harm to swimming water but also increase the density of harmful organisms (coliform and feacal coliform) and be a source of diseases for dwellers and tourists. The economic development and enlargement of Ha Long City in the future will be followed by the increase in that to pollute environments, among which is water environment, both in various fonns and levels whose impacts on life will include economy, health, etc. Conclusions and Recommendations The Project of Ha Long Bay Water Environment Quality has taken interest in full problems of the physical conditions, socio-economic conditions as well as hydrobiological featues. In the project, some major indicators were used to . determine water environment quality, pollutant suppliers, to assess possible affects . on ecosystems and the health of dwellers, to predict probable state of pollution in the future and propose strategies for managing and monitoring water environment of the area. The results obtained have indicated the present status of pollution of Ha Long Bay waters caused mainly by oil feacal materials, domestic, suspensions, etc. as found in Baichay embayment, water along the Baichay beach and Hon Gai coast. Though in a low level and small scale, there are certain affects on the health of dwellers and ecosystems among which arc coral reef. Faced with the plan for development of "A 1-Ia Long City in the future", promoting tourism and port economy, the problem of pollution will be more serious, both in a higher level and larger scale. It is obvious that the plan for developing Ha Long City in the future into a big center of industry, port and tourism in the Northeast of Vietnam is in conflict interest with the protection of environments for sustainable development in the common. In our endeavour to solve the problem of the conflict, it is necessary to make right away a detailed plan for managing and protecting environments consisting of appropriate measures to promote propaganda and community education of knowledge of environments and enforcement of state functions. Beside these, the problem also requires strategies for treatment of water, prevention of pollution, a system of warning, finding and treating accidents, especially oil spills able to pollute. There will be abilities to protect sustainably 1-Ia long Bay water environment in which beautiful landscapes arc famous and no where to be seen, as it were, if provided with help from local authorities and the Government as well as international organization. Our heartfelt gratitude for the great and efficient help is to the state of the Canada owing to and the organiza~ions of IDRC and VISED, ESSA, Environment Department and International Coope~ation Service (MOSTE, Vietnam), People's Administration Committee of Quangninh Province, service of science, Technology and Environment of Quangninh Province and the Haiphong Institute of Oceanology. 97 MAIN REFRENCES 1. Alice LC. Chan and C. Kim Wong, 1993. Impact of eutrophication on marine plankton into Tolo Harbour. 1988-1989. Proceedings of the First International Conference on the Marine Biology of Hong Kong and South China Sea. Hong Kong, 28 October - 3 Nov.ember, 1990. 2. &hley Bangrove, 1994. Consultancy Report on Water Environmental Quality of Halong Bay, Vietnam. 3. Dean F. Martin, 1972. Marine Chemistry. New York. 4. Dieu L V. and others, 1994 Survey Report on Water Environmental Quality of Halong Bay. Interim Report, Haiphong. 5. Hoi N. C., Dieu L V. and others, 1994. Background report on diagnostic review of the state of water environment in Halong Bay, Vietnam. Interim report. Haiphong 6. 1-Iy N. D. and others, 1993. Provisional Environmental Criterias. Scien. and Tech. Publishing House, Hanoi. 7. James E. Brower and Jerrold H. Zar, 1984. Field and Laboratory Methods for general ecology. 2nd Edit. Wm C. Brown Publishers, Dubuque, lOW A 8. Jean Pierre Quignaux, I 992. Halong Bay Project 2000 (in French). Hanoi. 9. Kong M. F, 1990. Marine Water Quality in Hong Kong. Annual report of Hong Kong Government. 10. Marry Ann Franson, 1975. Standard Methods for the Examination of Water and Wasterwater. 141h Edit. Washington. 11. UNEP, 1988. Determination of DDTs and PCBs by Capillary Gas Chromatography and Election Capture Detector. Regional Seas. Reference methods for marine pollution studies No. 40. 12. UNEP, 1983. Detennination of total coliform in sea-water by the membrane filtration culture method. Regional seas. Reference methods for marine pollution studies No. 2. Rev. 1. • 98 ILLUSTRATION PHOTOGRAPHS OF THE SURVEY. 1. 1l1e boat with a power engine used to work in Halong Bay. 2. Sampling plankton on boat. 99 3. Taking hydrochemical samples. 4. Measuring hydrochemical factors on the boat by "W ater Quality Checker W QC-1 A". 100 , ... ·- ~ ' . ·:;1. l I.t r ~-- -... \ . . -- . . ~- ' i '( ~ 5. Taking sediment samples. 101 ILLUSTRATION PHOTOGRAPHS OF HUMAN ACTIVITIES. I. The oil port in Halong Bay. 2. Bai Chay ferry. 102 3. A coal port in I-Ialong Bay. 4. A floating oil market on the sea. 103 5. Tourism boatt , 6. Fishing ground and market on the sea. 104 7. Rubbish dump on the beach. 8. A hotel at the Bai Chay beach. 105 9. Filled up ground at lion Cai shore. 106 Annex 3: Long - term water Quality Monitoring. (Tentative proposal of Second phase) Ha Long Bay has been given World Heritage Listing by UNESCO. So Ha Long Bay Master Plan (HLBMP) a long - term project. However, it provides initial valuable data on pollution sources which will quid the economic, industrial, urban and social development of the Ha Long Bay region into the next century. The WEQHB project is shoot-tenn project. However, it provides initial valuable data on pollution sources and water quality conditions in the Ha Long Bay and can be of considerable use in the 1-ILBMP. in addition, the WEQHB project can provide the baseline environmental data required for long-term monitoring of water quality in the Ha Long Bay are. This is absolutely necessary if the environmental impacts of HLBMP are to be identified, measured and evaluated in a scientifically valid manner over next decade. In order to ensure the highest degree of utilization by 1-ILBMP agencies, ESSA suggested and HIO would like to submit to VISED and IDRC a proposal which is a simplified water quality monitoring strategy in Ha Long Bay. The proposal is to be implemented as a follow-up to the WEQHB project, if funding can be obtained. 1. Purpose. The purpose of the proposed strategy is to, following on the initial work conducted by the WEQHB project, continue monitoring water quality in order to : • Assess current water quality conditions. • Identify long-term water quality trends. • Identify priority pollution sources. • Evaluate the overall water quality impacts of the 1-ILBMP. 2. Pollution source identification. Based on the results of the WEQI-IB project, the rank of pollution sources have been confirmed and suspected : • Oil poiiutant from seaport ( Oil port B12). • Oil spill from ship accident (if possible). • Domestic waste from settlement and 1-Ia Long City. • Suspended solid from coal dust (coal mining) and coal transport across the Ha Long Bay. 3. Develop Sampling strategy : • Bi-annual sampling is required in order to determine short-term and long-term domestic waste and suspended solid fluctuations. • Sampling should be monthly for oil pollutant. • Analysis parameters are :oil content, suspended solid, feacal coliform (or total coliform), BOD, COD, NI-13, N02-, N03-, Phosphorus-total, Dissoved Oxygen and Oxygen Saturation. 107 • Number of stations : (see fig. A3. ) • The Sediment samling and analysis at each station. 4. Review existing sampling and analysis Equipment : A boat, a water sampler and a computer for processing and managing data, A water quality checker should be purchased. Budged accordingly is about 10,000 USD. 5. Purchase required sampling and equipment. 6. Conduct field work as per Schedule developed in step 3. 7. Conduct laboratory analysis as per Schedule developed in step 3. 8. Reporting. Bi-annual rcport.5: Procedure bi-annual summaries of environmental conductions in Ha Long Bay and submit then at the minimum to the following agencies: • National Environmental Department (MOSIE). • National Information Center (MOSIE). • People's committee of Quang Ninh Province. • Department of Science, Technology and Environment of Quang Ninh Province. Annual reports: These reports should provide: • An overview of current environmental conditions in Ha long Bay. • Identification of the priority pollution sources. • Assessment of long-term environmental Quality trends. • Assessment of environmental impacts arising directly from development occurring as a results of the Ha Long Bay Master Plan. • Appropriate policy and legislation recommendations to address the above noted concerns. Annual reports should be submitted the same agencies as are the semi-annual reports. 108 ~H_._f0.: ,,. ~~' . ,,. 0 . 0 d. [) "c~-1 .. ~ 0 0 ······-n b;, Fig A3. Scheme of station network for sampling water quality 109 Annex4 Chromatograms of Gas Chromatographic Procedure for Organochlorine Pesticides 110 ~-.~ <..) •.0 I Cf'\ lf\ ~ 0 ~ - - ~ ~ - ·_ ------·- - -~ ...... , I I ~ ~ (1\1 ----- 0 \: -!'._ ~ o-.J I ("I ~ "'1 H .. ,~ ..... 0 ~t i:' ""tr.... ~ c ~~ --'~--7- "1_ " ~1 ~ I ""< \- u! f- I' #"o ~ co \ll .... 1-l ,., ~ .c ~I I,) ;,..:: <) r£ 4' ~ ... C'l C'·l I - ~~ Cf'\ " .-... C"!) Cf'\ "".!' .--< .--< 0 0 ~ ... .-... <"1 0 l.f\ ~t .-... u ·~> ...... z 0 u ...... II ~ 0: (') 0 f- ~· .:-s b ~ (Y' .~: :::;: I u I I .'I ~• if\ If\ •.0 0 If\ "'i' "'i' •.0 -::1' <'·1 1.0 I\:)"" ll 0 'I \ I 'I f'\ . I • I In ' ::' i \ ·I ~~• I :~I 0• ~r C'l ·,, I OJ 0 w 9 (jl 0 ·- ..... ~ \ , • r ··'I )': \ .01 J:>o ""() "J . \ I ~ 'Y.) 00 ,_ --:!' ...... I.(\ ""1' •.0 •.0 I I I(') In <:> ...... I I .- . - -- - '- - - -· .. - L -- 112 223·02000·12 00207.1A mJSHfMADZU ev(~ I~ -vi...... i I 0 .:.;;..------:______' t>J "' I ~ ~ ~{ I t:,' 1f" 1' 4'; .. 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