E-CONTENT
WATER POLLUTION
CLASSIFICATION
OF WATER POLLUTANTS
ANALYSING
Water pollution is
defined as the addition of an excess material or heat that is harmful to the
living organism or which impairs the beneficial uses of water. Pollution makes
water physically impure, foul or filthy.
·
Pollution changes the natural qualities
of water, so that it becomes unsuitable for the uses to which it is normally
put to.
·
Pollutants may be present in water
either as suspended particles or as dissolved compounds or both.
·
The dissolved compounds are more
difficult to remove and hence these taint the water resources more seriously
than the suspended impurities.
DESIGNING
Related to the topic,
four images and a video are shown. The video gives information about water
pollution and the images are shown to get an idea about different types of
water pollutants.
DEVELOPMENT
INTRODUCTION
Water pollutants are classified
in to four broad categories chemical, physical, physiological and biological.
The introduction of these contaminants in to the aquatic system is likely to
cause health hazards, harm to ecology, damage to structures or amenities and
interference with legitimate uses of water.
CHEMICAL POLLUTANTS
Chemical contaminants are
subdivided into organic and inorganic pollutants.
ORGANIC
POLLUTANTS
Organic pollution is the most common form of
water pollution. It is caused by the naturally
occurring compounds like proteins, fats, carbohydrates etc as well as by
synthetic compounds like dyes, pesticides, herbicides etc. The synthetic
organic pollutants cause more harm to the environment than naturally occurring
ones.
INORGANIC
POLLUTANTS
These pollutants largely
originate from industrial wastes. Inorganic acids and alkalis can do extensive
damage to a water body by breaking down its natural buffer system and altering
its normal pH values.
PHYSICAL POLLUTANTS
The onslaught on the natural
qualities of water occurs not only when chemical constituents are introduced in
the aquatic systems, but also when the physical parameters of water are
drastically altered. Physical pollution is less damaging than chemical
pollution.
COLOUR
Many trade wastes
discharging in to watercourses have a distinct colour which these may impart to
the water. The colour in most cases is due to organic dyes.
TURBIDITY
A distinct physical characteristics
of sewage and industrial waste is their degree of turbidity which is caused by
the presence of colloidal matter.
SUSPENDED
MATTER
Insoluble matter suspended in water is the
most common form of physical pollutant.
FROTH
Froth or foam consists of a
dispersion of gas bubbles in water. The formation of foam is a physical
phenomenon, arising due to lowering of surface tension of water by impurities.
THERMAL
POLLUTION
Thermal or temperature pollution
refers to the discharge of heated water from electricity generating plants in
to water resourses.
PHYSIOLOGICAL POLLUTANTS
Physiological
pollution is always a secondary phenomenon, arising from the presence of trace
quantities of chemicals.
TASTE
Industrial wastes
contain many chemical compounds which impart characteristic and unpleasant
taste to water, even when present in extremely small quantities.
ODOUR
Under the influence of
microorganisms, proteins undergo putrefaction giving intermediates having
offensive odours.
BIOLOGICAL POLLUTANTS
The aquatic organisms
which either multiply excessively or are otherwise undesirable, harmful or
injurious are classified as biological pollutants.
WEEDS
Excessive growth of
fresh water weeds is because of discharge untreated sewage or effluents in to
water.
ALGAE
Algae multiply at an
accelerated pace, causing odours in water.
BACTERIA
The faecal
contamination of water can introduce a variety of pathogenic bacteria into
waterways.
VIRUSES
Viruses are introduced
into natural waters through faeces. Although these organisms are present in
water in much lower members than bacteria, yet they pose a considerable health
hazard because they possess a greater resistance to disinfection.
PROTOZOA
Faecal contamination of
drinking water is the major sourse of transmission of pathogenic protozoa.
TESTING
The content was tested
by an expert teacher in the subject. The way of expressing the topic, the
language used, spelling mistakes, content errors, clarity of pictures was
checked and suggestions were given. The testing was also done on how much the
content was applicable and understandable to the readers.
IMPLEMENTATION
Finally the content was
uploaded in a learning management system where the students can easily get
access to the knowledge they want and they can get a clear idea on the topic that they want to
learn.
EVALUATION
The Feedback from the learners and
instructors are considered for further evaluation. After checking the feedback,
the content is re-designed for effective delivery of the topic.
