Measures for Preventing Water Contamination

Measures for Preventing Water Contamination;- contamination of water sources with compounds that prevent the water from being used for purposes such as drinking, cleaning, swimming, and others. Chemicals, garbage, bacteria, and parasites are examples of pollutants. Water is eventually contaminated by all types of pollution.

Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth’s hydrosphere and the fluids of all known living organisms. It is vital for all known forms of life, even though it provides neither food, energy, nor organic micronutrients. Wikipedia

Sources of Water Supply

Two Main Sources of Water Supply  

• Surface water
• Ground water

Surface Water

• The most common source of water for most people
• Located in rivers, lakes, streams, reservoirs, oceans, dams, and rain water and snow when it falls to the surface

Advantages of surface water

• Easily accessible
• Obtained by hand or by simple pumps
• Large lakes and rivers are permanent supplies of water throughout the year

Disadvantages of surface water

• Easily and frequently polluted as it runs over the ground where humans and animals wash and bathe in it
• May be polluted by chemicals used in agriculture or industry
• Surface water needs to be treated before it becomes drinking water

Types of surface water  

Rain water

• Obtained during the rainy season and collected from roofing or other collecting surfaces

Advantages of rain water

• Purest form of natural water if collected into clean, closed tanks
• Does not need treatment when collected in a clean container

Disadvantages of rain water

• Does not contain essential elements (fluoride, iodine, selenium)

Sea water

• Water from the sea contains some salts
• The water is concentrated by evaporation and become too salty for drinking

Ground Water

• Water which passes through permeable subsoil to the surface
• Ground water can be accessed through:
• Springs
• Wells (shallow well, deep well or Artesian/bore-hole wells)
• Shallow well taps water above the first impermeable stratum
• Deep wells are those derived from water bearing strata below a least one impervious stratum
• Artesian wells are the result of ground pressure in an aquifer being released through a natural fault, or a bore-hole, so that water is forced to the surface of the ground

Advantages of ground water sources

• Underground water is usually clean, often plentiful and permanent
• A reliable resource, especially in dry season
• Not affected by evaporation
• Ground water doesn’t need treatment as surface water

Disadvantages of ground water sources

• Limited resources, extractable quantities are often low compared to surface water
• Ground water extraction is more expensive due to pump cost
• Water from deep wells and deep springs usually has a lot of dissolved salts and other
• Fertilizer and insecticides can get washed into aquifers via rain water and pollute ground water

Sources of Water Contamination

Sources of Water Contamination

Industrial and mining activities

1. Industrial discharge of chemicals wastes and by products
2. Spillage of petroleum products
3. Acidic rain caused by industrial discharge of sulphur dioxide
4. Underground storage tank leakages
5. Heavy metals used in mining industries (mercury in gold mining)
6. Silt in storm water runoff from construction sites or cleared land

Agricultural activities

1. Farmers use of fertilizers and pesticides
2. Food processing wastes, including pathogens
3. Excess nutrients added by runoff containing detergents or fertilizers

Organic materials from human/animals/plants and other living organisms

1. The collecting surface for rain water may have leaves, insects, bird and animal faces
2. When water runs over the earth it may become contaminated with human or animal excreta and solid waste
3. Shallow wells may be contaminated by excreta and refuse being washed into them, if a latrine is near
4. Wells may also be contaminated by the use of dirty containers for drawing water, or by oil from the pump
5. Rivers, lakes or dams may be contaminated by bathing and/or urinating or defecating in the water
6. Even piped water may be contaminated from leaks in the pipes especially when these pass near foul water or dirty drains
7. Water may go bad if it is stored for too long in a pot or cistern
8. Water from any source may become contaminated if it is drunk from dirty or communal drinking vessel

Measures for Preventing Water Contamination

The following are measures for preventing water contamination:

• Protection of springs water
• Construct concrete water-proof protection box over the spring
• Keep off  sources of water from contamination e.g. fencing the source of water
• Protection of well water
• Site the well on a higher level of the source of water
• Put a concrete cover over a well
• Fence the well to keep animals away
• Protection of rain water
• Construct gutter that collects rain water from entire roof-surface and drains into an angled pipe

Key Points 

• There are two major types of water, i.e surface water and ground water
• Water contamination can occur from  industrial,mining,  agricultural activities; and materials from human, animals and  plants
• Various measures can be used to protect water from contamination

References

• Basset W.H. (1992).  Clay’s Handbook of Environmental Health (16^thed).  London: Chapman and Hall.
• Nyamwaya, D. (1994): A Guide to Health Promotion through Water and Sanitation, Nairobi: AMREF
• Subi, S. (2008).Environmental Health Hand Book for Clinical Officer Students. Kilosa, Tanzania.
• Wood C. H. (1997). Community Health (2^nded). Nairobi: AMREF