Measures for Preventing Water Contamination
Session 7: Measures for Preventing Water Contamination
Total Session Time: 120 minutes + 2 hours Assignment
Prerequisites
Learning Tasks
By the end of this session studentsare expected to be able to:
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |5 minutes |Presentation |Introduction, Learning Tasks |
|2 |25 minutes |Presentation |Sources of Water Supply |
| | |Buzzing | |
|3 |30 minutes |Presentation |Sources of Water Contamination |
| | |Small Group | |
| | |Discussion | |
|4 |30 minutes |Presentation | Measures for Preventing Water |
| | |Small Group |Contamination |
| | |Discussion | |
|5 |10 minutes |Presentation |Key Points |
|6 |10 minutes |Presentation |Evaluation |
|7 |10 minutes |Presentation |Assignment |
SESSION CONTENTS
STEP1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing
STEP 2: Sources of Water Supply (25 minutes)
|Activity: Buzzing (10 minutes) |
| |
|ASK students to pair up and buzz on the following question for 2 |
|minutes |
| |
|What are sources of water supply? |
| |
|ALLOW few pairs to respond and let other pairs to add on points not |
|mentioned |
| |
|WRITE their response on the flip chart/board |
| |
|CLARIFY and SUMMARIZE by using the content below |
Two Main Sources of Water Supply
Surface Water
water and snow when it falls to the surface
Advantages of surface water
year
Disadvantages of surface water
and animals wash and bathe in it
Types of surface water
Rain water
collecting surfaces
Advantages of rain water
Disadvantages of rain water
Sea water
o The water is concentrated by evaporation and become too salty for
drinking
Ground Water
o Springs
o Wells (shallow well, deep well or Artesian/bore-hole wells)
one impervious stratum
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
o Underground water is usually clean, often plentiful and permanent
o A reliable resource, especially in dry season
o Not affected by evaporation
o Ground water doesn’t need treatment as surface water
Disadvantages of ground water sources
o Limited resources, extractable quantities are often low compared to
surface water
o Ground water extraction is more expensive due to pump cost
o Water from deep wells and deep springs usually has a lot of dissolved
salts and other
o Fertilizer and insecticides can get washed into aquifers via rain
water and pollute ground water
STEP 3: Sources of Water Contamination (30 minutes)
|Activity: Brainstorming (10 minutes) |
| |
|ASKstudents to brainstorm on the following question: |
| |
|What are the sources of water contamination? |
| |
|ALLOW few students to respond |
| |
|WRITE their responses on the flip chart/ board |
| |
|CLARIFY and SUMMARISE by using the content below |
Sources of Water Contamination
o Industrial discharge of chemicals wastes and by products
o Spillage of petroleum products
o Acidic rain caused by industrial discharge of sulphur dioxide
o Underground storage tank leakages
o Heavy metals used in mining industries (mercury in gold mining)
o Silt in storm water runoff from construction sites or cleared land
o Farmers use of fertilizers and pesticides
o Food processing wastes, including pathogens
o Excess nutrients added by runoff containing detergents or fertilizers
o The collecting surface for rain water may have leaves, insects, bird
and animal faces
o When water runs over the earth it may become contaminated with human
or animal excreta and solid waste
o Shallow wells may be contaminated by excreta and refuse being washed
into them, if a latrine is near
o Wells may also be contaminated by the use of dirty containers for
drawing water, or by oil from the pump
o Rivers, lakes or dams may be contaminated by bathing and/or urinating
or defecating in the water
o Even piped water may be contaminated from leaks in the pipes
especially when these pass near foul water or dirty drains
o Water may go bad if it is stored for too long in a pot or cistern
o Water from any source may become contaminated if it is drunk from
dirty or communal drinking vessel
[pic]STEP 4: Measures for Preventing Water Contamination(30 minutes)
|Activity: Small Group Discussion ( 15 minutes) |
| |
|DIVIDE students into small manageable groups |
| |
|ASK students to discuss on the following question |
|What are the measures of preventing water contamination? |
| |
|ALLOW students to discuss for 10 minutes |
| |
|ALLOW few groups to present and the rest to add points not mentioned |
| |
|CLARIFY and SUMMARIZE by using the contents below |
The following are measures for preventing water contamination:
o Construct concrete water-proof protection box over the spring
o Keep off sources of water from contamination e.g. fencing the source
of water
o Site the well on a higher level of the source of water
o Put a concrete cover over a well
o Fence the well to keep animals away
o Construct gutter that collects rain water from entire roof-surface and
drains into an angled pipe
STEP 5: Key Points (10 minutes)
activities; and materials from human, animals and plants
STEP 6: Evaluation (10 minutes)
STEP 7: Assignment (10 minutes)
|Activity: Take Home Assignment (10 minutes) |
| |
|DIVIDE in small groups assignment |
| |
|ASK the students to work individually on the following Assignment |
|Prepare a list sources of water contamination |
|Describe preventive measures against the list you have mentioned |
|ALLOCATE time for students to do the assignments and submit |
| |
|REFER students to recommended references |
References
Basset W.H. (1992). Clay’s Handbook of Environmental Health (16thed).
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 (2nded). Nairobi: AMREF
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