Water quality facts and statistics (part 4)

WATER QUALITY FACTS AND STATISTICS

Global water pollution

? Every day, 2 million tons of sewage and industrial and agricultural waste are discharged into the world’s water. (UN WWAP 2003)
? The UN estimates that the amount of wastewater “produced” annually is about 1,500 km3. (UN WWAP 2003)

Human waste

? Lack of adequate sanitation contaminates watercourses worldwide and is one of the most significant forms of water pollution. Worldwide, 2.5 billion people live without adequate sanitation. (UNICEF WHO 2008)
? 70% of the people who lack sanitation worldwide, i.e. 1.8 billion people, live in Asia. (UNICEF WHO 2008)
? Sub-Saharan Africa is the slowest of the world’s regions to achieve improved sanitation: only 31% of residents had access to improved sanitation in 2006. (UNICEF WHO 2008)
? 18% of the world’s population, or 1.2 billion people (1 out of 3 in rural areas), defecate in the open. Open defecation significantly compromises quality in nearby water bodies and poses an extreme human health risk. (UNICEF WHO 2008)
? In Southern Asia, 63% of rural people – 778 million people – practice open defecation. (UNICEF WHO 2008)

Human health impacts

? Worldwide, infectious diseases such as waterborne diseases are the number one killer of children under five years old. More people die from unsafe water annually than from all forms of violence, including war. (WHO 2002)
? Unsafe or inadequate water, sanitation, and hygiene cause approximately 3.1% of all deaths worldwide and 3.7 % of DALYs (disability adjusted life years) worldwide. (WHO 2002)
? Unsafe water causes 4 billion cases of diarrhoea each year, and results in 2.2 million deaths, mostly of children under five. This means that 15% of child deaths each year are attributable to diarrhoea – a child dying every 15 seconds. In India alone, the single largest cause of ill health and death among children is diarrhoea, which kills nearly half a million children each year. (WHO and UNICEF 2000)

Impacts on the environment

? There has been a widespread decline in biological health in inland (non-coastal) waters. Globally, 24% of mammals and 12% of birds connected to inland waters are considered threatened. (UN WWAP 2003)
? In some regions, like the Mediterranean and Madagascar and other island groups in the western Indian Ocean, more than 50% of native freshwater fish species are at risk of extinction, and nearly one-third of the world’s amphibians are at risk of extinction. (Vié et al. 2009)
? Freshwater species have faced an estimated extinction rate five times greater than that of terrestrial species. (Ricciardi and Rasmussen 1999)
? Freshwater ecosystems sustain a large number of identified species, including a quarter of known vertebrates. Such systems provide more than US$75 billion in goods and ecosystem services for people, but are increasingly threatened by a host of water quality problems. (Vié et al. 2009)

Drinking water quality

? Point-of- use drinking water treatment through chlorine and safe storage of water could result in 122.2 million avoided DALYs (Disability Adjusted Life Years, a measure of morbidity), at a total cost of US$ 11.4 billion. (UN WWAP 2003)
? Nearly 70 million people living in Bangladesh are exposed to groundwater with arsenic above WHO recommended limits of 10 ug/L. (UN WWAP 2009)
? Naturally occurring arsenic pollution in groundwater now affects nearly 140 million people in 70 countries on all continents. (UN WWAP 2009)

Costs and benefits of water quality

? With the Millennium Development Goals, the international community committed to halving the proportion of people without access to safe water and sanitation by 2015. Meeting this goal would mean an extra 322 million working days per year gained, at a value of nearly US$ 750 million (SIWI 2005), and an annual health sector cost saving of US$ 7 billion. Overall, the total economic benefits of meeting this MDG target are estimated at US$ 84 billion. (SIWI 2005)
? Poor countries with access to clean water and sanitation services experienced faster economic growth than those without: one study found the annual economic growth rate was 3.7 % among poor countries with better access to improved water and sanitation services, while similarly poor countries without access had an annual growth of just 0.1 %. (Sachs 2001)
? Sanitation and drinking water investments
have high rates of return: for every $1 invested, there is a projected $3-$34 economic development return. (UN WWAP 2009)
? Economic losses, due to the lack of water and sanitation in Africa as a result of the mortality and morbidity impacts, are estimated at $28.4 billion or about 5% of GDP. (UN WWAP 2009)

Pollution from industry and mining

? 70% of untreated industrial wastes in developing countries are disposed into water where they contaminate existing water supplies. (UN-Water 2009)
? An estimated 500,000 abandoned mines in the U.S. will cost $20 billion in management and remediation of pollution; many of these sites will require management in perpetuity. (Septoff 2006)
? In the U.S. state of Colorado alone, some 23,000 abandoned mines have polluted 2,300 km of streams. (Banks, et al. 1997)
? Chlorinated solvents were found in 30 %  of groundwater supplies in 15 Japanese cities, sometimes ending up as much as 10 km from the source of pollution. (UNEP 1996)
? Roughly one unit of mercury is emitted into the environment for every unit of gold produced by small-scale miners. A total of as much as 1000 tons of mercury is emitted each year. (UNEP/GRIDArendal 2004)

Pollution from agriculture

? In a comparison of domestic, industrial, and agricultural sources of pollution from the coastal zone of Mediterranean countries, agriculture was the leading source of phosphorus compounds and sediment. (UNEP 1996) Nutrient enrichment, most often associated with nitrogen and phosphorus from agricultural runoff, can deplete oxygen levels and eliminate species with higher oxygen requirements, affecting the structure and diversity of ecosystems.
? Nitrate1 is the most common chemical contaminant in the world’s groundwater aquifers. (Spalding and Exner, 1993) Mean nitrate levels have risen globally by an estimated 36% in global waterways since 1990, with the most dramatic
increases seen in the Eastern Mediterranean and Africa, where nitrate contamination has more than doubled. (GEMS 2004)
? According to various surveys in India and
Africa, 20-50% of wells contain nitrate1 levels greater than 50 milligrams/litre and in some cases, as high as several hundred milligrams per litre. (cited in FAO 1996)

Groundwater impacts

? In Chennai, India, over-extraction of groundwater has resulted in saline groundwater nearly 10 km inland from the sea and similar problems can be found in populated coastal areas around the world. (UNEP 1996)

Infrastructure affects water quality

? 60 % of the world’s 227 biggest rivers have interrupted stream flows due to dams and other infrastructure. Interruptions in stream-flow dramatically decrease sediment and nutrient transport to downstream stretches, reducing water quality and impairing

Source: worldwaterday2010.info

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