State and Trends
and higher turbidity from stronger, frequent storms and erosion from deforestation provides favourable growth conditions in tropical estuaries for bacteria such as Vibrio that causes cholera (Lara et al. 2009). Other diseases related to water, sanitation and hygiene include intestinal nematode infections,
protein-energy malnutrition, trachoma,
schistosomiasis, lymphatic filariasis, malaria and dengue. Disability-adjusted life years lost due to unsafe water, sanitation and hygiene in the region totals 24.78 million per year (Anand 2012).
Another factor affecting human health from water pollution is the accumulation of heavy metal in plants that are then consumed as food. Many studies have looked at accumulations of arsenic, cadmium, copper, lead and mercury in vegetables, rice and other edible plants (Arunakumara et al. 2013; Lu et al. 2015). The extent of bioaccumulation depends on irrigation methods, much less arsenic accumulation has been observed in rice grown by sprinkler irrigation compared to that grown using continuous flooding irrigation (Spanu et al. 2012).
Water pollution affects mammals and birds using inland water sources: globally 24 per cent of mammals and 12 per cent of birds are estimated to be threatened by it (Pacific Institute 2010). Freshwater fish and amphibians also face the risk of extinction. Changes in river flows due to infrastructure developments, which can reduce the transport of nutrients downstream, also impact ecosystems. Freshwater ecosystems provide more than USD75 billion in goods and services that can be threatened by water quality problems (Pacific Institute 2010). Fragmentation of rivers by dams has an adverse effect on the ecosystems besides impacting humans due to loss of flood plain fisheries and flood recession agriculture (Nilsson et al. 2005).
The risk of floods is increased due to soil erosion, accumulation of solid wastes in rivers, and changes in land- use patterns affecting flood plains and water runoff.
Because of frequent severe floods and droughts, the region’s water security is adversely affected by contamination of water and falling availability.
Rapid urbanization has led to increases in water demand and extraction of groundwater, particularly when surface waters are polluted. Extraction is one of the causes of land subsidence in coastal cities (Deltares 2015) including Bangkok, Ho Chi Minh City, Jakarta and Manila and increases the risk of flooding and damage to critical infrastructure and buildings.
Water security is a concern in this region that is undergoing rapid urbanization, and climate change could lead to conflicts due to competition for this limited resource.
2.5 Coasts and oceans
2.5.1 Introduction Asia and the Pacific’s coastline (Table 2.5.1) has multiple shore types. The region contains the world’s two largest archipelagic nations (Indonesia and Philippines) and all five of the world’s nations that are entirely atolls (Kiribati, Maldives, Marshall Islands, Tokelau and Tuvalu).
Approximately 45 per cent of the world’s mangrove forests are on its tropical and subtropical coasts and approximately 40 per cent of the world’s coral reef area is in Southeast Asia (Hijioka et al. 2014). The Coral Triangle of 5.7 million square kilometres covering the ocean waters of Indonesia, Malaysia, Papua New Guinea, the Philippines, Solomon Islands and Timor-Leste (Hijioka et al. 2014) is recognized as the global centre of marine biodiversity based on its extremely high biodiversity and goods and services value (APEC 2014). In the South Pacific, the exclusive economic zones (EEZs) and the connecting high seas of 15 island states that cover nearly 40 million square kilometres of the Pacific
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