About 70 percent of the Earth’s surface contains water and an estimated 96.5 percent of this is trapped in glaciers. Saline or brackish groundwater and saltwater lakes including large inland seas make up another 1 percent and the remaining 2.5 percent of the water on Earth is fresh and therefore potentially available for drinking, irrigation, and industrial use. Two-thirds of this, however, is frozen in the polar ice sheets and glaciers. The remaining 0.8 percent is held in aquifers, soil pores, lakes, swamps, rivers, plant life, and the atmosphere. As a result, only about 0.3 percent of the total water on Earth is available for human use.
The primary sources of drinking water are groundwater and surface water. Others include: precipitation (rain) can be collected and used. Water within the upper water table can be accessed through dug wells. Groundwater located in deeper reservoirs or aquifers can be accessed through wells that are driven or drilled. Springs represent another source of groundwater. Sources of surface water include lakes, reservoirs, and rivers. Surface water may also come from protected watersheds. Each of these sources has its advantages and disadvantages.
Kenya has an annual renewable fresh water supply of approximately 647m3 per capita and hence is classified as a water scarce nation. 17 million people in Kenya don’t have access to safe drinking water. This water crisis disrupts numerous social and economic activities and also results in poor health and sanitation.
This means that the demand for water is greater than the renewable freshwater resources that Kenya has access to. [source-https://sites.google.com/site/isat380ekenya/_/rsrc/1362105328837/home/water-budget/water%20resources.png]
Surface water sources like rivers, lakes are on the decline due to drought and climate change and very polluted and contaminated making the situation worse and resulting in a decline in water quantity and quality.The constant decline in water quality is due a number of different factors;
a) Population growth.
Population increase results in two things; one is the overuse of resources since the number of people depending on a resource increases. More water will be drawn from a river or lake or reservoir hence leading to a reduction in water quantity. At the same time, population increase results in an increase in wastes. The higher the number of industries and agricultural farms and homes, the higher the wastes generated. When coupled with poor waste management, this leads to massive pollution and degradation and hence a decline in water quality.
b) Unsustainable economic activities.
These include agriculture, industrialization, deforestation and land clearance and to create space for settlements. In the case of agriculture; artificial and potentially harmful fertilizers and pesticides are used in large quantities in order to boost yields. Traces of these may reach streams, rivers and lakes through run-off leading to contamination and pollution of water bodies. Some of these contaminants may also infiltrate and reach underground water sources like springs and wells hence contaminating them. Deforestation on the hand leads to soil erosion and sedimentation of water bodies and also decrease in rainfall quantity.
c) Technology and technological consumption.
Example, use of coal, charcoal or petroleum products that release carbon dioxide, sulphur and nitrogen oxides into the atmosphere resulting in acid rain and hence contamination of water and water sources. Also, the use of charcoal and wood fuel results in deforestation and hence a disruption of rainfall patterns and hence a depletion in water sources.
d) Poor implementation of policies and legislations that protect and conserve water sources, like the five water towers (Mau complex, Aberdare ranges, Mt.Elgon, Mt.Kenya and Cherangani hills) which are critical catchment areas.
The effects of water pollution and poor water quality are far reaching:
i. Every year more than five million people, mostly children die from illnesses linked to unsafe drinking water. The main diseases associated with water quality include diarrhea, ascaris, hookworm, trachoma among others. In addition, the pollution also affects aquatic life which is our food sources. This can be explained through the three concepts bioaccumulation, bioavailability and biomagnification.
A pollutant is said to bio-accumulate when it reaches a concentration within a creature that is higher than found in the environment. For instance, PCBs and dioxins bio-accumulate in fat; strontium (a metal), fluoride and lead bio accumulate in bones; metals such as cadmium bind to proteins and bio accumulate in the liver, kidney, and other soft tissues of aquatic life like the fish we consume.
When a pollutant reaches progressively higher concentrations as it moves through the food chain/web it is said to biomagnify. For instance, Organic pollutants, PCBs biomagnify in the Lakes food web. At each step the PCBs concentration grows higher: phytoplankton, one-celled plants at the base of the food chain, bio accumulate PCBs. Zooplankton, small invertebrate animals eat enough phytoplankton to accumulate PCBs to levels higher than those in phytoplankton. In turn, smelt (small fish) eat enough zooplankton to raise their PCBs level above that of zooplankton. Lake trout eating the smelt have higher levels still. The eggs of herring gulls that eat the fish have a PCB concentration higher than lake trout, and dramatically greater than in the phytoplankton. Not only gulls, but other predators including humans may eat the contaminated fish, and also show very high PCB levels in their fatty tissues.
For a nutrient to be helpful, it must be in a physical and chemical form that an organism can access, it must be bioavailable. Likewise, to be toxic must be bioavailable.
Consider a charcoal administered to a poisoning victim; the charcoal absorbs the poison making it biologically unavailable. Likewise in the environment, certain chemicals including dioxins, PCBs, and PAHs bind tightly to soil or sediment particles. The chemicals may move into, and become trapped within a particle’s interior. There they are largely inaccessible, i.e., they are not bioavailable. An animal may ingest these particles, but the chemicals bound to them are not absorbed across the GI tract.
Consider different chemical form of mercury, methylmercury (CH3Hg+). Methylmercury is often ingested as a fish contaminant. It is easily absorbed across the intestine into the blood stream. It is thus much more dangerous. Chronically ingested, even tiny amounts can lead to health problems especially in small children.
ii. Poor water quality also results in poor sanitation and related illnesses. Water and sanitation go hand in hand; hence the numerous campaigns on importance of hand washing and proper hygiene.
iii. In urban settings traces of pollutants often reach households through tap water. A recent study shows trace elements of harmful pollutants in our household tap water. The treatments are not designed to completely get rid of all pollutants found in water. So the next time you dispose your wastes in a water body remember you are contaminating your own tap water.
iv. Apart from health issues, the aesthetic value of our water bodies is lost. This is instead replaced by rivers of wastes and repelling odors.
Ways to improve water quality.
One way is through improvement of public participation in water management and conservation efforts and proper waste management techniques.
Another way is through increasing the country’s forest cover. Trees not only stabilize the hydrological cycle and rainfall patterns, but some species also help in purification of water bodies.
Protection of water sources and management of catchment areas, like the 5 water towers. example, in order to ptotect lake victoria, we have to conserve the mau catchment first. If the catchment are destroyed then most if not all of our water sources will degrade too and dry up.
Proper waste disposal techniques in order to minimize pollution.
Considering water as of economic and social value. Water should be of maximum value, after all water is life.Water has an economic value in all its competing uses and should be recognized as an economic good. It is vital to recognize first the basic right of all human beings to have access to clean water and sanitation at an affordable price. Past failure to recognize the economic value of water has led to wasteful and environmentally damaging uses of the resource. [http://www.gwp.org/en/ToolBox/]. Managing water as an economic good is an important way of achieving efficient and equitable use, and of encouraging conservation and protection of water resources.
Efficient water use is important since it is an important ‘source’ on its own. Reduce wastage and overuse, use alternative water sources like rain water.