Continuing June 2008 paper - section B
Marjorie Henry, Contributor

I started the discussion of Question 9 from the June 2008 paper in the last lesson. Having already discussed section (a), I will now share with you section (b) of the question.

(b) (i) Define the term air pollution. (2 marks)

(ii) Describe THREE causes of river pollution in a named Caribbean country. (6 marks)

This section of the question is based on these specific objectives from the syllabus:

• define pollution
• describe the types of pollution

Please be advised that in answering subsection (ii), you must describe the way the water becomes polluted. In addition, you are to give the name of a Caribbean country where this is happening or has occurred. Here are possible answers to the questions.

(i) Air pollution is the contamination of the air by harmful or toxic substances.

(ii) There are several ways in which river pollution can occur. This can be as a result of industrial discharges or agricultural and urban activities.

• Industrial pollutants include sulphur and nitrogen, particles of heavy metals, persistent chemicals which get into the water supply and accumulate, and reactive organics that contribute to the formation of photochemical oxidants. These enter streams, polluting them.
• Industries discharge large amounts of waste materials. Some of these are raw sewage, livestock manure, discharges from slaughter houses, food-processing plants and other industrial firms. These are examples of organic pollution. When these enter the drainage system, there is an increase in plant growth. This reduces oxygen levels in the water, a process known as eutrophication. This process can kill wildlife in rivers, especially fish, for example in Jamaica.
• Chemicals from fertilisers and pesticides used in agricultural activities are the most common form of pollution from agriculture. They are washed into the soil and streams, thereby contaminating the water supply. For example, a section of the Rio Grande, Jamaica where large quantities of gramazone were found in the water in 2005.
• Clearing of land for cultivation causes erosion and leads to increased sedimentation in rivers. The beds of the rivers become blanketed, causing harmful changes in the spawning and rearing habitat of fish and altering food supply.
• Where there is irrigation, the water that runs off the fields carries with it sediments, fertilisers, pesticides and natural salts leached from the soil. These eventually enter the groundwater supplies and pollute the river.
• Increasing population, urban expansion and new housing projects affect both water quality and water quantity. There is an increase in domestic sewage and solid wastes. Much of this is being dumped into gullies and rivers. In some rivers large numbers of discarded cans and bottles can be seen floating. These, in turn, contribute to organic pollution. For example the Caroni River in Trinidad.
• Garbage in landfills and litter near water sources can also contribute to water pollution. Contaminated water from these landfills may also seep into groundwater reservoirs and pollute them. The polluted groundwater may flow out of the ground into streams and rivers and be consumed by human and animals.

Discussion on the last section of the question will be done in the next lesson.

Sources: CSEC New Integrated Geography by Sheldon G. Bleasdell et al;

Longman Geography for CSEC by Jeanette Ottley et al;

New Caribbean Geography by Vohn A. M. Rahil

José Marti student, Ann Rhoden, was the top achiever in agricultural science in the Caribbean Secondary Education Certificate examination for 2008. - Ian Allen/Staff Photographer