Water contamination: Can we stop the world’s biggest killer?

It may be surprising to some, but water-borne diseases are the leading cause of death in the world. There are an estimated 3.4 million deaths a year according to the World Health Organisation (99% of which occur in developing countries (Prüss-Üstün et al., 2008)), whilst four-fifths of illnesses in developing countries are caused by contaminated water (Fonyuy, 2014). Clearly the problem of water pollution and contamination is now one of the most pressing issues for developing countries.

So how does water get polluted? Surface water is more commonly contaminated, and this can pose a high risk as many public waterways are used for drinking and cooking water as well as sanitation. However, a lack of infrastructure in towns and cities can lead to sewage and garbage being dumped straight into these waterways. Groundwater is usually safer as it gets filtered as it passes through underground layers of sand, clay and rock (Kjellstrom et al., 2006). Nevertheless, industry and mining can affect the mineral and pH levels of both ground and surface water. Arsenic (especially a problem in southern Asia, including Bangladesh) and fluoride, can leech through the soil into groundwater from both natural and anthropogenic sources, and are seen as the most dangerous inorganic contaminants in the world (Farooqi, 2015). 

The overriding contamination of freshwater comes from nitrogen and phosphurus, which are carried into the water from agricultural runoff. This leads to eutrophication of water bodies, and enhanced productivity of algae to form toxic algae blooms. A consequence of the increased respiration rates is that it depletes the water of oxygen, which can create 'dead zones' with devastating effects on local fauna.

It is not just freshwater reserves which are being increasingly contaminated. Go to any beach in Britain and it’s easy to see the amount of waste and debris washed up onto our shores. There are billions of pieces of plastic floating around are oceans, right down to microscale which can have a devastating effect on wildlife. The BP oil spill in the Gulf of Mexico is a well-known example of water pollution, where 780,000 cubic metres of oil were released into the ocean, causing havoc to marine wildlife as well as the local fishing and tourism industries. Meanwhile, Diaz and Rosenburg, 2008 report more than 400 marine dead zones, caused by toxic algae blooms and oxygen depletion. 

 Why is freshwater contamination such an issue in developing countries, whilst in general richer ones are able to get around the problem? The answer, inevitably, focuses around money. Many developing countries lack the finances to build the necessary infrastructure, such as pipes, treatment plants and wells. The problem is being exacerbated in many African countries by high population growth rates, meaning increased use of unsafe water for drinking, cooking and sanitation.

However the developed world has its problems as well. Recently in the USA there have been reports of contaminated groundwater due to deposition of waste water from the hydraulic fracturing, or fracking, process of extracting natural gas. Although natural gas has been hailed as a cleaner alternative to coal, and a transition fuel whilst the world switches to a future which utilises renewable energy sources, it brings its own environmental impacts. Methane concentration has been found to rise with proximity to fracking sites (Holzman, 2011). This video shows an example of how methane levels are so high in some US drinking water supplies that they are actually flammable: 

This has led to a backlash against fracking in regions which are experiencing water pollution. Developed nations have higher expectations with regard to their water supply and are typically willing to take steps to protect the quality of that water.  

How realistic is it though, to expect to radically reduce water contamination in developing countries? Historically poorer agricultural countries are often the ones experiencing the most rapid economic growth, driven by increased globalisation and growing demand for minerals and other commodities.  This typically involves rapid expansion of cities, including the building of new factories and roads, but often without the infrastructure to support dealing with contaminated water.  

However preserving water quality and improving accessibility brings significant potential economic benefits due to a decreased spend on health and less time spent on collecting water, thereby increasing economic productivity. For a developing country to prosper, it is in their interest for economic growth and improvements to the water supply to go hand-in-hand.