INTRODUCTION
Water is an important necessity for the life and for producing Water is a gift given by natural that any country have However, with the development of economics and society, population explosion, polluted environment, climate change, etc make water become a serious problem in the whole world Because of increasing population and economic growth, water is increasingly being abused The process of urbanization, agricultural activities, industrial and climate change increasingly heavy pressure on the quantity and quality of water
There are also many important issues which need so much care about in the Vietnam, such as pollution of the ecological environment by the production and life of human caused
In big cities, like Hanoi or Ho Chi Minh City, the pollution is also need to pay attention It is the pollution of waste water, waste, medical waste, air, noise In recent years, urban population increased rapidly causing drainage system does not respond well and decrease the quality rapidly Waste water, waste (include inorganic and organic) in the city mostly directly discharged into the environment without any treatment measures environment other than transport According to the authorities, everyday people in the big cities discharged thousands of tons of trash, households also discharge hundreds of thousands of cubic meters of toxic waste
West Lake which locates in the north-west of Hanoi center is the largest natural lake in Hanoi West Lake is the largest natural lake in Hanoi The lake has an area of over 500 hectares (5.3 km²) with a perimeter of 18 km Lake is located in the Tay Ho district, north- west of center Hanoi The coordinate of West Lake is 21°3′18″ N and 105°49′12″ E Type of lake is fresh water lake The main water supply and the main drainage is Red River Researchers have proven, West Lake is a section of the old Red River after changing flow Tay Ho has relatively flat terrain that tends to be lower from the north to the south Tay Ho’s environmental conditions are important West Lake with an area of approximate 526 hectares is considered as the "lungs of the city” The area surrounding West Lake is planned to become the center of city in the near future West Lake’s ecosystem, flora and fauna are considered unique in the North Delta of Vietnam In addition, the lake also contributes to local flood controlling for the northwest area of Hanoi In the dry season (winter months), it plays the role of storing water and partially treating sewage of the city by automatic cleaning mechanism However, in recent years, the lake has been contaminated by overflowing rainwater and domestic wastewater from surrounding residential area This situation has been resulting in a lot of damage to not only the environment but also human life
From all of the reasons above, I decided to implement the student thesis proposal with the title of “Assessing the water quality of West Lake in Hanoi” This project will contribute to protect the environment and improve the water quality in West Lake
Figure 1.1 Map of the study area (Source: Google map)
GOALS AND OBJECTIVES
Goals
Through fact-finding, sampling and analyzing data and statistics on water quality of West Lake in Tay Ho district (Hanoi), the thesis aims to figure out solutions to improve the water quality and protect the ecosystem of West Lake
The thesis was carried out to achieve the objectives as follows:
- Collecting data on natural conditions, population and socio - economic conditions of area surrounding West Lake;
- Sampling, analyzing, and assessing the current status of water quality in the study area around West Lake;
- Initially identifying major impacts of water contamination in the study area around West Lake;
- Proposing solutions to improve the water quality and protect the ecosystem of West Lake.
METHODS
Investigating the study area
Because the lake is large (the diameter is 18km and the area is 5.3 km²) and with the scope of a student thesis, the selected study area will be a part of the lake to investigate the general state of the lake, near the edge for easily taking water samples The thesis also chooses some investigating area surrounding the lake to better assess the situation of the lake
So thesis will choose about 3 investigating area locations Each investigating area must have a distance from other one about 1 km After choosing the study area, thesis will preliminarily investigate the following information:
+ Different types of activities in the study area:
+ Primarily assess the water quality of the lake by some visual indicators;
- Waste water from boathouse which are made to be restaurants, bars in the lake;
- Waste water from households live around the lake;
- Trash from people who throw to the lake.
Interviewing
From the results of investigating the study area, I will interview 20 people who live near the edge of West Lake, with random address Thesis uses interviewing method to investigate information on the understandings of local people about water quality of West Lake The information is summarized on Table 3.1
Table 3.1 Results of interviewing people live around West Lake area
Their knowledge on the status of water quality of West Lake
Activities affecting the lake’s water quality
Major impacts of water contamination that they can feel
Their proposed solutions to improve and protect the lake’s water quality
Assessing the water quality of West Lake
Based on the purpose of research and analysis conditions, the thesis chooses the following indicators to analyze and assess:
- Physical criteria: pH, turbidity, temperature, content of suspended solids (TSS) and content of dissolved solids (TDS)
- Chemical criteria: BOD 5 (Biological Oxygen Demand), and COD (Chemical Oxygen
3.3.2 Selecting locations and sites of sampling
Because the area of the lake is large and the thesis’s scale is limited, the selected study area is from the beginning of Thuy Khue street to Phu Tay Ho The total length of West Lake is 18km The red dots present for 3 positions for taking water samples Each place is about 1km far away from each other The time for taking samples is 9.00 in the morning (at that time, demand of using water from resident is much)
The data of water samples will be filled in the following table:
Table 3.2 Water samplings of West Lake
The middle of the lake
Take water from lake by plastic bottle
Distance about 1km from the edge
Take water from lake by plastic bottle
The edge of the lake
Take water from lake by plastic bottle
3.3.3 Tools and methods for sampling
Tools and methods used for sampling follows the standards:
TCVN 6663-1:2011 (ISO 5667-1: 2006) – Water quality- Sampling Part 1: sampling guides and techniques
TCVN 6663-3:2008 (ISO 5667-3:2003) – Water quality- Sampling Guidelines of sample preserving and processing
TCVN 6663-6:2008 (ISO 5667-6:2005) – Water quality - Sampling Sampling guidelines on rivers and streams a Sample container
Sample containers should resist the loss due to evaporation, absorption and contamination by strange substances The desired factors when selecting sample containers are: durable, solid, easy-sealed, easy to open, withstand heat, weight, reasonable shape and size, easy to clean and can be reused, easy to find and cheap
To ensure the above requirements I selected the white bottle of plastic of 500ml for sample container While sampling should clean the bottle and sampling at any location have to rinse 3 times with water at that location b Sampling tools
All sampling bottles and containers must be clean It is possible to use detergent and acidic solution to sterile instruments and then rinse thoroughly with distilled water The samples were taken by plastic bottles with a capacity of 1.5 liters Additionally, when conducting sampling, it is required to prepare tapes, markers, sealed barrel sponge c Preserving and transporting of samples
All water samples in bottles have to cool about 4 o C and transport to the laboratory, separate target pH, and temperature measured directly in place Make cold and put in the dark place, most of the samples usually durable to 24 hours
This thesis took 03 water samples at the same time Water samples were taken in the morning at about 9.30, because at that time, demand of using water from resident is the most, in one day and sunny day
+ Step 1: Selecting and cleaning 03 bottles which are used for collecting water samples; + Step 2: Cleaning again by the West Lake’s water, douse bottles into the lake with the depth of 0 – 20 cm, preventing trash goes into bottles;
+ Step 3: Covering the bottle and writing background of the water sample clearly (time, collector…)
+ Step 4: Preserving the water samples following the standard
3.3.4 Analysis Methods a pH measurement method pH was measured by litmus paper and then compared the color of litmus paper with color table to determine the pH of the water b Temperature measurement method
Use a thermometer directly at the sampling location and record the results c Turbidity measurement method
The turbidity of the water samples was measured by fast measuring device as Micro TPI d NH 4 + measurement method
The N + measurement method of the water samples was measured by TCVN 5987-1995 e PO 4 3- measurement method
The PO4 3- measurement method of the water samples was measured by TCVN 2322 f COD measurement method
The COD measurement method of the water samples was measured by strong oxidation factors like K2Cr2O7 g Method of analysis of Total Dissolve Solid (TDS)
The total dissolve solid of water was measured by fast measuring device as TDS Meter h Method of analysis of suspended solids
Suspended solids SS is calculated by the formula:
Where: m1: Weight of filter paper dried at 105 0C until constant weight before filtrating (g) Drying time is about 45 minutes m2: Weight of filter paper dried at 105 0C until constant weight after filtrating (g) Drying time is about 45 minutes
V: Sample volume filtered (L) i Methods for determination of BOD 5
The samples analyzed were considered are very high levels of BOD 5 , they are diluted to the appropriate factor before analysis Water used to dilute the oxygen was bubbled to saturation and the nutrients necessary
After diluting the sample, measured the value of DO0 at 200C then incubated in a BOD dedicated pocket at 2000C in 5 days Re-measured the value of DO5 after incubating we calculated the value of BOD 5 (mg / L) BOD 5 value is the value obtained after subtracting the values of BOD5 in the blank sample
BOD 5 : BOD values after 5 days (mg/L)
DO0: DO values at 200C after diluting (mg/L)
DO 5 : DO values at 200C after 5 days incubating at 200C (mg/L)
F: dilution factor j Method for determination of COD ( Ferroin Indicator reagent)
- b is the volume of FAS (Ferrous Ammonium Sulfate) used in the blank sample,
- s is the volume of FAS in the original sample,
- n is the normality of FAS k Methods for determination of coliform
The analysis results will be filled below:
Table 3.3 Analyzing results of some water indicators of West Lake
The thesis uses the following standards of Vietnam to assess the water quality at the research area:
- QCVN 38:2011/BTNMT: National technical regulation on Surface Water Quality for protection of aquatic lifes
- QCVN 39:2011/BTNMT: National technical regulation on Water Quality for irrigated agriculture
- QCVN 40: 2011/BTNMT: National Technical Regulation on Industrial Wastewater
- QCVN 02: 2009/BYT: National technical regulation on domestic water quality
Table 3.4 Limits of water quality indicators
QCVN 38:2011/BTNMT: National technical regulation on Surface Water Quality for protection of aquatic lifes
3 Total Suspended Solids (TSS) mg/L 100
4 Total Dissolve Solids (TDS) mg/L 1000
QCVN 39:2011/BTNMT: National technical regulation on Water Quality for irrigated agriculture
3 Total Dissolve Solids (TDS) mg/L 2000
QCVN 40: 2011/BTNMT: National Technical Regulation on Industrial Wastewater
- Column A is the limit values regulation of pollution indicators in discharging of industrial wastewater into water sources used for domestic water supply purposes
- Column B is limit values regulation of pollution indicators in discharging of industrial wastewater into water sources not used for domestic water supply purposes
QCVN 02: 2009/BYT: National technical regulation on domestic water quality
RESULTS AND DISCUSSION
Socio - economic conditions of Tay Ho district
Socio - economic conditions of Tay Ho district
Since its foundation day, Tay Ho District has been building and developing the economic structure that follows the trend of "Services – Industry - Agriculture" The value of industrial production has reached an average growth of 31.2%/year; value of traveling services and trade has increased on average of 14.9% / year; value of agricultural production and fisheries has decreased an average of 3.8% / year (Portal gate of Tay Ho district)
In 2008, the industrial production value reached 177.2 non-state billion VND; commercial sales-service-tourism reached 4992.4 billion VND; agricultural production value was estimated at 15.45 billion VND Particularly the first 6 months of 2009, industrial production value reached 79.13 nonstate billion VND, reaching 45.3% of the plan; commercial revenue-services reached 2847.02 billion VND, reaching 47.3% of the plan; agricultural production value reached 6 billion VND, reaching 42.9% of the plan State budget revenues in the district has been increasing pace of development, in 2008 reached 368.75 billion VND; 6 months of 2009 reached 148.19 billion VND (Tay Ho district portal gate)
The issue of social policy, employment, poverty reduction is concerned and implemented effectively In the first 6 months of 2009, Tay Ho district had jobs for 2608 workers They reduced poverty to 21 households, reached 35% of the plan Material life and spirit of the people is improving effectively Information and cultural activities are promoted and implemented with the results The policy of government "All people unite to build cultural life" went into the life of all residents, the people in the area support with a strong enthusiastic If in 1996, the ratio of household standards of cultural families is 78%, then by
West Lake is a land of ancient cultural monuments, 62 historical monuments which is ranked 31 national monuments such as Tran Quoc Pagoda, Phu Tay Ho Van Nien pagoda, the temple of Tao Books, Uc Nien Pagoda, Kim Lien Pagoda Additionally, Tay Ho district also includes West Lake scenic area - one of the largest freshwater lakes in Hanoi capital, with about
526 ha area is considered the "lungs of the city"; Publicity and lake West Lake Water Park.
Current status of West Lake’s water quality
Water samples were taken from 9h30 to 10h30 on 17 th August 2015 at the edge of West Lake The samples were analyzed in the laboratory The results are shown in table 4.1.
Table 4.1 Analyzed results on water quality of West Lake
West Lake is used for purpose of tourism and business Therefore, water quality of West Lake can be compared with standards of B2 Chemical, biological and physical indicators of West Lake exceed to the limits listed in column of B2 In addition, the analytical turbidity results are 5 times greater than the standard of 02:2009/BYT In general, from observing when working with samples, investigating residents or from indicators, this kind of water can not be used for daily purposes of local people
Graph 4.1 Analyzed results of pH for West Lake’s water
As we can see, pH of West Lake’s water of all 3 samples are in the limits of levels of B1 and B2 of QCVN08
Sample 1 Sample 2 Sample 3 pH pH pHAverageLower limit QCVN 08Upper limit QCVN 08
Graph 4.2 Results of turbidity indicators in West Lake
The analytical turbidity results on the table show that the values of this indicator are greater about 5 times than the standard of 02:2009/BYT Therefore, this kind of water can not be used for daily purposes of local people
Graph 4.3 Results of COD indicators in West Lake
Turbidity Average Limit of QCVN 08
CODAverageLimit of QCVN 08
In this table, the COD indicators of water samples taken in West Lake are below of QCVN 08 The highest COD indicators is just only 12.5 mg/l in sample 1, on the other hand, permitted level indicators of QCVN 08 B1 and B2 is 30 - 50 This thing is acceptable of water quality in West Lake
Graph 4.4 Results of NH 4 + indicators in West Lake
With this table, the NH4 + indicators of water samples taken in West Lake are above of QCVN
08 for purpose B1 and B2 The lowest indicator is 7.21 mg/l, it is 7 times higher than permitted level of QCVN 08 The highest indicator is 9.64 mg/l, it is more than 9 times higher than the permitted level of QCVN 08 That means it is very polluted and can’t be used for living
Graph 4.5 Results of PO 4 3- indicators in West Lake
In this PO4 3- table, all of indicators taken in West Lake are lower than 0.1 That mean the amount of PO 4 3- in water of West Lake is very small, or may do not have This is good indicators of PO4 3- in West Lake
Graph 4.6 Results of TSS indicators in West Lake
TSSAverageLimit of QCVN 08
Like COD and PO 4 3- , TSS indicators of West Lake are also below the QCVN 08 for purpose of using water B1 and B2 The highest TSS indicator is only 53, higher a little bit than QCVN 08 level B1 That is accecptable of water quality in West Lake
Graph 4.7 Results of coliform indicators in West Lake
In this table, the indicators about coliform show that this indicator at all the positions meet the standards of QCVN 08 B1 and QCVN 08 B2
Coliform Average Limit of QCVN 08
For TDS, the results analyzing water samples of West Lake show that this indicator atmeet the standards 38:2011/BTNMT and 39:2011/BTNMT
Graph 4.9 Results of BOD 5 indicators in West Lake
And the last indicator, BOD5, is also meet all the standards of QCVN 08 for purpose B1 and B2 of all 3 place
Major impacts of water contamination on the ecological functions and living quality
Table 4.2 Knowledge of people about water quality of West Lake
Knowledge about water quality of West Lake
As we can see from table, no one agree that water quality of West Lake is clean, some people even do not know the water quality of West Lake (5 people, take 25% of people asked) And a large numbers of people asked think that West Lake is polluted seriously
BOD5AverageLimit of QCVN08
Table 4.3 Impacts affecting the water quality of West Lake Impacts that affecting the water quality of West Lake
Numbers of people know about it
People live near the lake 17 35.2
From the table above, almost people who were asked agreed that behavior of people live near the lake affect most to the water quality of West Lake (35.2%) Besides that, awareness of people and business around the lake also contribute a large part to pollute to the lake (18.7%) Some people thought major caused to the status of water quality in West Lake may be producing, from visitors, or entertainment, but it is not the main major Waste water, mainly from restaurants, boats and from residential area are flowed directly to the lake without treatment This is very dangerous, heavily impacts the purity of West Lake
There are many reasons for West Lake become seriously polluted as today, but the main cause of the situation, is action and human consciousness Everyday, West Lake likes a enormous ''trash'' for people to litter every kind of waste Resident who live near West Lake throw waste into the lake for "convenience" Although around the lake have public trash but many residents and tourists often do not hesitate always discharged into the water With all kinds of garbage and thousands of bamboo poles down because people do spot for fishing everyday, everyhour is one of the direct causes to environmental of West Lake water pollution
Besides household waste, the yacht floating houses along the West Lake activities is the day that the condition of the lake are becoming increasingly worse It seems that for- profit, business owners restaurant may forget about the protection of "lungs" of the capital Around the floating restaurant on Thuy Khue Street, Tay Ho District, Hanoi City, flooded waste sludge all tobacco shells, cans, wrappers, nylon unpleasant odors This is the environment to grow rampant dirt, bacteria proliferate so that no species can survive
With a situations such as West Lake, the authorities have no action to react to this situation for affecting people Ms Hong, people living along West Lake said: "Since the day had little yacht floating house, west of the lake water is increasingly polluted The ever- expanding restaurant, littering directly to West Lake makes source Water smelled very unpleasant”.
Solutions
As in part 4 of thesis (Results and discussions), the thesis has proved that this kind of water can not be used for daily purposes of local people Water quality of West Lake is declining due to operational activities and economic development of the people live near the lake To control water quality of West Lake, thesis give some solutions below:
4.4.1 Locations and characteristics of the waste generator discharged to West Lake
- Residential area around the lake: including in the area of Thuy Khue Street, Lac Long Quan Road, Au Co Road, Yen Phu Street,, Trich Sai Road It need to determine the location, population; water standards; percent waste of water
- Three boats on the lake: Taboo bar on the boat, and Tay Long 2, Tay Long 3 boat used for tourism It need to find out the numbers of customers, waste water treatment systems, how these boats interactive to the lake
- Restaurants, coffee in the area around the lake, such as Maxx coffee, Poseidon coffee Also need to find out how these restaurants and coffee deal with waste water and how they interactive to the lake
As the study results above, people in the study area do business a lot, and without properly water treatment system They litter around the residential areas and West Lake So education to raise awareness for environmental protection should be more concerned:
+ Organizing the contests to research about knowledge of environmental protection and West Lake water quality, create governmental agencies and community
+ Providing some educational contents about the awareness of environmental protection in schools and extracurricular meetings villages
4.4.3 Enhancing the management capacity of local authorities
Local authorities are managers who understand community the most In fact, the management in the study area is still shortcoming due to the limited capacity of some cadres Therefore, the training and fostering the capacity of leadership, expertise and scientific knowledge for cadres also need to concern We can open some extra-curricular meetings at local with the participation of some experts and environmental organizations
The policies are to open the way for the project, the model is implemented smoothly,
In addition it helps to contribute, promote and replicate of the project
- The planning policies of using the cultivation land along the river, particularly forest land
- Preferential policies for organizations, households with actively participate in the environmental protection and development of forests
- Policies to support capitals and techniques to the infrastructural construction to protect the dike and river bank
- Policies on environmental management and forest management
The scientists said that for the West Lake and other lakes of Hanoi city, the need to modify and complete sewer system around the lake to collect and prevent 100% of wastewater, run-off into lake There is such a new water reservoirs quickly recovered as clean as the water in the 60s of last century Moreover, these measures also need to conserve bio- diversity of species of the West Lake
The responsibility to preserve, conserve green space Westlake is not only the work of the scientists, professional bodies, local authorities, but the consciousness of the people also need to be improved and strengthened to contribute to the cause of keeping clean Westlake.
CONCLUSIONS 26 REFERENCES
From the time do the student thesis proposal, internship and do the field trips in the area of West Lake, this thesis proposal make clear some points:
The area surrounding West Lake is planned to become the center of city in the near future Therefore, actions which relate to business are increasing The numbers of restaurants and cafe are increasing rapidly People from other places come here to live is also increasing
In addition, awareness of people to protect the lake is not good Those things make West Lake becomes more and more polluted
With the purpose of using water for tourism and business, West Lake may be listed for B1 or B2 standard Indicators about chemistry, biological and physical overcome a little with a standard of B1 and B2, such as pH, NH4 + but it can be acceptable
Generally, water quality of West Lake become polluted gradually because of business, waste water flow directly to the river, and bad awareness of people live around.