Hi Urban Nomads! Welcome to another episode of the Urban chronicles. This week we will be focusing on the environmental impacts of mass tourism in Halong Bay.
Halong bay, being a World Natural Heritage attracts thousands of tourist every year to marvel at the landscapes that have been molded by nature. This generates big profits for Vietnam’s tourism; in particular the Quang Ninh province ( where the Halong bay resides) . In conjunction with the state’s policy of the development of the provinces in Hanoi, Quangninh has became a Nation Point Economic Trigange area of the North due to the boom in the tourism and service industry.
To cater to the large amount of tourist, the water environment in Halong Bay is under strained by the rising influx of industrial, agricultural, and domestic waste. At present, water sample measurements in Halong Bay shows signs of pollution by oil and coliform. Other pollutants; namely heavy metals, chlorinated pesticides and organic matter are also above the limits set by the state for water management.
- Impacts of inland waste sources to water quality of Halong Bay
The water in Halong Bay has been affected predominantly by industrial and domestic waste. This arises as the tourism activity in Halong bay incites the demand for goods and services to feed the industry. Hence, discharge of heavy metals and big amount of suspended solid into the bay are common, negatively impacting water quality. Furthermore, large amounts of trash have been discarded into the waters. The plastics are not biodegradable, thus posing an environmental issue to the organism residing there.
Table 1. Range of pollutant concentration discharged into the Halong Bay
| Parameter | Industrial waste | Domestic waste | River | |
| Fine days | Rainy days | |||
| BOD5 (mg/l) | 5.54 – 275 | 7.42 – 23.48 | 0.13 – 3.54 | 0.54 – 8.10 |
| COD (mg/l) | 18.42 – 766.27 | 19.2 – 175.73 | 0.98 – 13.46 | 4.22 – 31.69 |
| Oil (mg/l) | 0.5 – 3.6 | 0.4 – 3.3 | 0.7 – 3.1 | 1.3 – 3.0 |
| CN–(mg/l) | 6 – 840 | 0.36 – 13.6 | 6.2 – 10.8 | |
| Phenol (mg/l) | 7.2 – 339 | 0.16 – 1.32 | 0.3 – 0.6 | |
| Coliform (MPN/100ml) | 1680 – 340000 | 18600–108000* | 640 – 73500 | 1240 – 79360 |
| Cr6+ (mg/l) | 2.12 | 1.86 – 3.12 | 0.98 – 1.96 | |
| Pb (mg/l) | 2.91 – 3.26 | 3.75 – 8.75 | 2.94 – 4.21 | |
| As (mg/l) | 1.38 – 3.38 | 0.54 – 3.26 | 1.60 – 2.70 | |
| Cd (mg/l) | 0.34 | 0.24 – 0.46 | 0.39 – 0.50 | |
| T-Hg (mg/l) | 0.19 – 0.32 | 0.16 – 0.49 | 0.27 – 0.46 | |
* Feacal coliform
Table 1 shows the risk of pollution of organic, coliform and oil in the upper limits. In addition, much attention is needed on pollutants such as cyanide, phenol & especially heavy metals as these metals have ability to be stored in not only fat, tissue but also marine sediment.
- Pollutants in Halong Bay water
GESAM (Joint Group of Experts on the Scientific Aspects of Marine Pollution) defines marine pollution as the introduction by “man, directly or indirectly, of substances or energy into marine environment thereby leading to deleterious effects; namely harm to living resources, hazards to human health and the impairment of quality for use of sea water”. This highlights how the problem of pollutant is a multifaceted one. These forms of pollution such as oil slicks and rubbish are easily visible, but there should also be an equal importance on the “invisible” pollution such as heavy metal contamination —where these pollutants can wreak havoc on marine ecosystems and human health.
Pollution along Halong bay
- Oil and grease
The point sources of oil in Halong Bay are a result of tourism activities form the tourist boats. In an interview with a boat operator, he mentions how “there were simply too much tourist and too little boats”. The engine that power such boats are predominately diesel. These engines are unrefined and produce not only thick smog, but also suffer from oil leaks due to the lack of maintenance.
This Oil spot that occur in the bay would spread, evaporate, diffuse and cling into suspended solids; settling into the riverbed. This adversely impacts the landscape environment in Halong Bay. Many species which are part of the underwater ecosystems suffer when oil cling into body, preventing it from respiring, and therefore killing them in the progress. Fun fact: Oil concentration of about 0.1mg/l, in water is enough to kill planktons. (Nhuan, B.D., 2001).
- Heavy metals
Certain heavy metals in minute concentration are essential elements that organism living in river water needs. Some metals are considered as pollutants; Cadmium, chrome, lead, mercury, and nickel. The presence of these heavy metals when in excess level (see in Halong bay) will affect to water body because of their toxicity. Heavy metals have the ability to be stored in fat, tissue, and marine sediments. At Halong bay area, the burning of Coal in nearby processing factories are used for the nearby hotels to meet energy demands. This process releases a lot of metals (Sulphur) into the air ( Sulphur dioxide), which may unfortunately enter the bay area in the form of Sulphuric acid.
- Pesticides
Pesticides are used widely in agriculture in Vietnam to ensure crop stability for farmers. With the large influx in tourist, there is a need to feed them. Thus, local farmers have been pressured to use pesticides to ensure that to ensure a stable crop supply which can be sold off to nearby restaurants. The use of chlorinated pesticides are so toxic impart as they are not only carcinogen but also can accumulate in the environment with half-time decompose of 10 years. These pesticides can penetrate the environment through any stages in crop production, package, transportation and usage; suggesting its difficulty in containing it.
Table 2. Average concentration of some pollutants in Halong Bay water
| Parameters | Cua Luc | Bai Chay | Hon Gai | Average |
| DO (mg/l) | 5.19 | 4.03 | 5.15 | 4.79 |
| BOD5 (mg/l) | 1.35 | 1.65 | 1.05 | 1.35 |
| COD (mg/l) | 7.45 | 6.45 | 9.3 | 7.73 |
| Oil and grase (mg/l) | 3.5 | 1.25 | 2.4 | 2.38 |
| CN- (mg/l) | 6.55 | 8.55 | 7.55 | 7.55 |
| Phenol (mg/l) | 1.2 | 1.55 | 1.8 | 1.52 |
| Cu (mg/l) | 6.59 | 8.16 | 5.88 | 6.88 |
| Pb (mg/l) | 2.46 | 2.42 | 1.99 | 2.29 |
| Zn (mg/l) | 12.51 | 9 | 12.56 | 11.36 |
| Cd (mg/l) | 0.22 | 0.15 | 0.23 | 0.20 |
| Cd6+ (mg/l) | 1.21 | 0.96 | 1.28 | 1.15 |
| Ni (mg/l) | 2.86 | 2.25 | 2.85 | 2.65 |
| Mn (mg/l) | 22.91 | 16.48 | 24.83 | 21.41 |
| Fe (mg/l) | 25.6 | 16.34 | 25.03 | 22.32 |
| As (mg/l) | 2.07 | 2.39 | 2.31 | 2.26 |
| Hg-T (mg/l) | 0.22 | 0.39 | 0.23 | 0.28 |
Table 3. Average concentration of some pollutants in Halong Bay water
|
Parameter |
Unit |
Surface |
Bottom |
Permitted limit | ||
| Bathing | Aquaculture | Others | ||||
| CODMn | mg/l | 5.95 | 6.57 | |||
| BOD | mg/l | 1.19 | 1.30 | <20 | <10 | <20 |
| Oil and grease | mg/l | 1.4 | 1.0 | None | None | 0.3 |
| Coliform | MPN/100ml | 5986 | 3627 | 1000 | 1000 | 1000 |
| CN– | mg/l | 7.61 | 8.50 | 10 | 10 | 20 |
| Phenol | mg/l | 1.62 | 0.98 | 1 | 1 | 2 |
| Pb | mg/l | 2.48 | 2.84 | 100 | 50 | 100 |
| Cd | mg/l | 0.19 | 0.25 | 5 | 5 | 10 |
| Cr | mg/l | 1.68 | 1.95 | 50 | 50 | 50 |
| As | mg/l | 2.26 | 2.50 | 50 | 10 | 50 |
Conclusion
Mass tourism places a huge environmental strain in Halong Bay. Limited resources are being stretched thinly to ensure that it meet the needs of both the tourist and locals. As more people flock from all corner of the globe to see the beautiful and pristine sights of Halong Bay, little do they know that of the environmental impact it brings about. In an ironic twist, such natural sties rely heavily on funds of the tourism industry for site preservation —but it is precisely due to this industry that destroys the pristine environment of Halong Bay (thereby threatening its existence). Perhaps, the next time you embark on trips to see such natural heritage sites, you would be more aware of your ecological footprint on the environment. The sties you see now might only exist in postcards in the near future if no measures are implemented.
References:
News, T. (2015). Half of Ha Long Bay tourist boats face suspension for waste treatment failure. Retrieved from http://www.thanhniennews.com/travel/half-of-ha-long-bay-tourist-boats-face-suspension-for-waste-treatment-failure-53016.html
Vietnam News Agency (2018). Plastic waste – serious threat to environment. Retrieved from https://en.vietnamplus.vn/plastic-waste-serious-threat-to-environment/129846.vnp
Ho, H. H., Swennen, R., & Van Damme, A. (2010). Distribution and contamination status of heavy metals in estuarine sediments near Cua Ong Harbour, Ha Long Bay, Vietnam. Geologica Belgica, 13, 37-47.
S., & MINAMI, T. (2020). Water quality index analysis of water pollution of ha long bay, vietnam. Kankyō Gijutsu, 49(4), 209-213. doi:10.5956/jriet.49.209ca, 13(1-2), 37.