thematic framework
Clean water — a future luxury? Clean water is essential to life and the economy. All ancient civilizations developed close to water bodies. Even today, more than half of the global population lives 3 km or nearer to a surface freshwater body and only 10 percent of the population lives more than 10 km away, according to Kummu et al. (2011)1. However, many of our freshwater bodies suffer from high and growing levels of water pollution with adverse
health impacts for humans and animals. Moreover, freshwater aquatic biodiversity is in rapid decline and now more threatened than terrestrial biodiversity. Poor water quality is a key contributor to this decline. Water quality refers to the physical, chemical and biological properties of water. Many substances which could influence water quality, such as organic matter, nitrogen, and phosphorus, are natural elements found in air and water bodies around the globe. However,
water quality deteriorates when excessive amounts of these substances are discharged into aquatic environments due to human activities and natural, climate factors. Human sources of emissions, including household waste, agricultural chemicals, and livestock waste, all find their way into water bodies and cause pollution if untreated or not managed appropriately. Non-human sources of emissions enter into water bodies from uninhabited or uncultivated lands as a result of precipitation, runoff, and other climate factors. Water pollution is generally classified into two categories – point sources and nonpoint sources. Point source pollution stems from easily identifiable distinct sources, such as sewage treatment plants and industrial sources. Non-point source pollution generally consists of sediment, nutrients, organic and toxic pollutants, and originates from more diffuse pollution sources such as agriculture, urban storm water runoff or other land uses. Point sources are easier to monitor and measure, and thus are generally the first to be dealt with in water pollution regulations. In most developed countries point source pollution is already well regulated, while many developing countries are still struggling with regulation for both types of pollution. The future of clean water Projected population growth, socioeconomic development and climate change over the next few decades cast uncertainty on the fate of aquatic environments. It is unclear to what
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen required by microorganisms in the water to break down organic material. It measures the quantity of organic pollutants in water. Nitrogen (N) and Phosphorus (P) are nutrient elements for life. They are important to maintain the health of aquatic ecosystems. However, too much N and P in water lead to pollution. A major consequence of excessive nitrogen and phosphorus in water bodies is eutrophication, when algae grow faster than normal killing other aquatic life by depleting oxygen. The presence of nitrogen-based compounds is also harmful in drinking water.
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Words into Action