Major Environmental Concerns  

[ Land | Forest | Biodiversity | Water | Marine & Coastal Environments | Urban & Industrial Environments ]

Underlying Causes

[ Social | Economic | Institutional | Environmental ]

Most people in the region live along the coasts, with one quarter of the world's 75 largest cities being near or on the region's coastlines (ESCAP, 1995a). Growth rates of coastal populations are generally higher than the national average due to migration to coastal urban areas and industrial centres. Most of these large cities and industrial areas are located in highly productive low-lying estuarine areas.

The marine resources of the region are economically important to most countries, with 47 per cent of world fisheries production being found in this region. Of this, marine and fresh-water fisheries account for 76 per cent and 24 per cent of production, respectively (FAO/RAPA, 1994). The region is also the centre of global mariculture (87 per cent of total world production) (FAO/RAPA, 1994), with major consequences for coastal habitats and water quality.

For insular and archipelagic states, marine resources are the key source of external earnings for development and marine-based tourism is playing an increasingly important role. Several countries rely almost exclusively on fisheries products for dietary protein. Trends show that the marine fish catch is rising steadily in almost all subregions. The average annual fish catch is comparatively higher in South-East Asia .

Coastal and marine pollution in this region is mainly due to direct discharge from rivers, surface runoff and drainage from port areas, domestic and industrial effluents, and various contaminants from ships. River waters are generally heavily contaminated by municipal sewage, industrial effluent, and sediments. Asian rivers account for nearly 50 per cent of the total sediment load (13.5 billion tons) transported by the world's rivers each year (UNEP, 1992).

As much as 70 per cent of the waste effluent discharged into the Pacific Ocean has no prior treatment (Fuavo, 1990). More than 40 per cent of marine pollution in the region is derived from land-based activities through riverine discharge, with maritime transport contributing a further 12 per cent (Weber, 1993). The Government of Korea estimates that at least 80 per cent of pollutants in the Yellow and South seas of the Korean Peninsula come from inland activities (domestic and industrial) through the four largest Korean rivers (Government of Korea, 1994).

The major sources of heavy metal contamination are industrial effluent and dumping of land-based solid waste into the sea. In India , for example, exceptionally high concentrations of lead, cadmium, and mercury have been observed in Thane creeks on the Bombay Coast , and sediment along the creeks and offshore stations was reported to contain significant concentrations of lead ( India , 1993). In Pakistan , heavy metal contaminations have been detected in water and sediment from the coastal area within the mouth of the Indus River (Tariq et al., 1993). Moreover, there is increasing evidence of these toxic substances getting into the food chain.

The sources of marine pollution from sea-based activities include marine transportation and offshore mineral exploration and production activities. Accidental oil spills have been frequently reported along these routes.

In the Straits of Malacca alone, 490 shipping accidents were reported in 1988-92, resulting in a considerable amount of oil spillage (Straits Times, 1993). It has been reported that beach tar along the west coast of India is a severe problem, with total deposits of up to 1,000 tons per year (GESAMP, 1991). In the port of Chittagong in Bangladesh , an estimated 6,000 tons of crude oil is spilled annually, while crude oil residue and wastewater effluent from land-based refineries amount to about 50,000 tons per year (Khan, 1993). Approximately 5 million tons of oil enter the Arabian Sea each year, while the Bay of Bengal receives some 400,000 tons from similar sources (ESCAP, 1995a). Similarly, oil pollution from shipping and offshore oil rigs is a concern in East Asian seas.

Increased use of agro-chemicals in this region is also a matter to be considered. Fertilizer consumption rose 74 per cent in 1982-92, from 33.3 million to 57.8 million tons (ESCAP, 1995a). Use of pesticides, which contribute to enhanced agricultural productivity, appears to be increasing, especially in developing countries. An estimated 1,800 tons of pesticides enter the Bay of Bengal annually (Holmgren, 1994), and increased use of pesticides in some areas has resulted in contamination of shell-and finfish.

Loss of coastal habitats includes substantial loss of mangrove forests in South-East Asia , particularly for the construction of shrimp ponds and for paddy rice cultivation, with negative impacts on commercial fisheries that rely on species using the mangroves as nursery areas. Thailand and the Philippines are clear examples: some 208,218 hectares and 200,000 hectares of mangroves, respectively, were cleared between 1961 and 1993 (GESAMP, 1993). Identical problems because of shrimp culture have occurred in Bangladesh , India , and Sri Lanka . One example of this destructive sequence of events is the Chakaria Sundarbans in eastern Bangladesh , which have been almost completely cleared for aquaculture (ESCAP, 1995a).

Similarly, coastal construction (particularly for tourist facilities), inland mining, and poor land use practices have increased sediment loads in coastal waters in countries such as Fiji, Indonesia, Malaysia, and Thailand, with adverse impacts on sensitive coral reef systems. At present, the status of coral reefs has been significantly improved in Thailand , thanks to the efforts of non-governmental organizations and local people (OEPP, 1996).

Occurrences of "red tides," a special plankton bloom, has been an environmental problem of major concern in the coastal areas of the region. In addition to severely depleting oxygen levels, leading to the mass death of aquatic organisms, the red tides also cause a paralytic shellfish poisoning, with serious risks to human health. For example, an outbreak of red tides in the Philippines in 1990 proved costly for the fisheries and shellfish industries (ESCAP, 1995a). The frequency of the appearance of red tides in Tolo Harbour , Hong Kong , ranged from 2 in 1977 to 9 in 1994. China is also experiencing an increasing threat of red tides in its coastal waters; there were a total of 19 incidents of red tide in 1993 (ESCAP, 1995a).

A major cause for concern throughout the region is overfishing and the use of destructive fishing techniques, particularly in the highly diverse coral reef systems. Most stocks throughout the region are currently being fully harvested, while a number are being exploited at unsustainable levels. Increasingly frequent and severe toxic algal blooms and the eutrophication of bays and semi-enclosed water bodies are growing problems throughout the region. Coastal erosion resulting from increased land subsidence from ground-water extraction, sediment starvation as a consequence of inland dam and irrigation barrage construction, and offshore mining of sand are notable problems in some localities. The high volume of maritime traffic and rising numbers of international tourist arrivals pose additional threats to marine and coastal environments.

United Nations Environment Programme