BN 300: ENVIRONMENTAL BIOTECHNOLOGY PRACTICAL 1: POINT AND NON-POINT SOURCES OF CONTAMINATION
INTRODUCTION
One of the job descriptions of an environmental
inspector/officer is to understand contaminants and their origin for effective
environmental management (prevention, consultation, investigation, and
education of the community regarding health risks and maintaining a safe
environment). A contaminant is a
substance found where it shouldn`t be in high enough levels to have
a negative effect on our health or on
the health of animals or plants or the
environment have effects not only on fish, wildlife, and their habitat, but
also on human health. it takes
often years, if not decades
,before we may become aware
that a contaminant is having a harmful
effect on our natural resources
and, even if its use is enter the environment in many different ways. There are many types of contamination
sources, both point and non-point, that undermine and damage the ecosystem. In
Dar-es-salaam city, the contaminant sources of can be divided into two groups
.these consist of point and non –point source. point sources of contaminations occur
when harmful substances are
emitted directly into a part of the environment changes, often over a widespread area and its initial location is difficult to pinpoint, this means that
it is difficult to regulate or
even keep track of the contamination .In many cases, the
origin of contamination may not be as
clear , but if effect can be
observed in the environment .For example,
agricultural pesticides can be carried by runoff and end up contaminating a stream dozens of miles away. Pollutants can also be
carried for long distances through the air and deposited on land and in water
by rain. The more obvious sources of contamination include waste disposal ,gasoline
entering water bodies , chemicals and
salts from roadways washing into rivers,
and harmful toxins being released into the air. Science provides many practical solutions to minimizing the present level at which contaminants are
introduced into the
environment.contamination
prevention means ~ source of
reduction ~ which includes `other practices
that reduce or eliminate
the creation of contaminants
through (1) increased efficiency
in the use of raw materials,energy , water ,or other resources ,or (2) protection of natural
resources by conservation .Although in
developed countries point sources contaminants are generally better regulated , in developing countries point sources contaminants
are generally better regulated
,in developing countries like Tanzania
point sources contamination are not well regulated. therefore the aim of
this practical is to observe both point and non-point sources of contamination in the city of Dar es salaam
from selected site.
PROCEDURE
Our basic task was to visit,observe,take notes from a selected
contaminated site in Dar es salaam city which was the university of dar –es-salaam
landfill/dump using the proposed
guidelines below. With this field observation we examined various aspects of contaminants and their origin
1.
SITE ASSESSMENT
a) What is the
estimated size of the sites?
Answer: The sites was
about ……large and
b) What comprises the
contaminated sites?
Answer:
c) What type of
activity contaminated the sites?
Answer: That
contaminated sites has been contaminated by variety of intended, , or activities and
events such as waste disposal, accidental spills, legal and illegal dumping
d) Are the contaminated
sites in their level of “maturity” ( fully contaminated) or “ state of
progression “( contamination in progress)
Answer: The
contaminated sites in their state of progression “(contamination in progress)
e) Are contaminated
sites visited different? If yes or no give sound reasons for your answer.
Answer:
Yes,
because the contaminant that are on the contamination sites are from different
sources (point source of contamination,
and nonpoint source of contamination,also some emerging contaminants appeared
there )
2.
THE TYPES OF CONTAMINANTS
a) Explain briefly the
types of contaminants categories observed from the contaminated sites,
Answer:
They was some different
categories of contaminants
ü Oxygen
depleting organics: human waste
ü Metals,
we believed that their was the presence of these metals because on the sites
they was some laboratory and hospital wastes like old bottles of chemicals,
bags,.
ü Nuisance
substances: we also suspected the presence of these substances, because of
industrial waste, garage wastes, hospital waste, that appeared at the sites….
b) Are contaminants
organic or in organic in their origin?
Answer:
the contaminants are both organic and inorganic in their origin
c) What are the effects/risks of these contaminants
pose to the ecosystem?
Answer:
People that are exposed to toxic air pollutants at
sufficient concentrations and durations may have an increased chance of getting
cancer or experiencing other serious health effects. These health effects can include
damage to the immune system, as well as neurological, reproductive (e.g.,
reduced fertility), developmental, respiratory and other health problems. In
addition to exposure from breathing air toxics, some toxic air pollutants such
as mercury can deposit onto soils or surface waters, where they are taken up by
plants and ingested by animals and are eventually magnified up through the food
chain. Like humans, animals may experience health problems if exposed to
sufficient quantities of air toxics over time.
3.
CLASSIFICATION OF CONTAMINATION SOURCES
a) From sites
assessment and observation classify the sources of contamination into point and
non-point sources. Give specific examples observed from the contaminated sites.
Answer:
The sources of
contamination
Point sources:
Non-point sources:
b) While researching point
and non-point sources, did your
team discovered types of point and
non-point contaminants being of human origin? If your answer is yes or no give brief explanations
Answer:
Yes
4.
PRATICAL SOLUTIONS
Complete removal of
contaminant is economically and technically not reasonable, but to reach a
level where the risks are minimized, meaning in a more practical sense for the
concentration of the contaminants to fall below a threshold value.
What are the ways can be taken to decrease
contaminants in the sites visited?
Answer:
there are many ways of reducing the
contaminants :
ü Contaminants
should be prevented or reduced at the source whenever
feasible;
ü Contaminants
that cannot be prevented should be recycled
in an environmentally safe manner whenever feasible;
ü Contaminants
that cannot be prevented or recycled
should be treated in an
environmentally safe manner whenever feasible; and
ü Disposal
or other release into the environment should be employed only as a last resort
and should be conducted in an environmentally safe manner
Use the following
criteria questions to judge your action plans for effective and efficient
reduction of contamination
1)
Which way is most cost-effective
Answer: Recyle and Reuse of the contaminants
2)
Which solution will best help us meet our goal
of a sustainable society and sustainable environment?
Answer: Recyling and Reuse of the contaminants
3)
Which solution will the people in the community around the contaminated
sites respond to best?
Answer: Recyling and Reuse of the contaminants
4)
Which solution will limit contamination
by humans the most?
Answer: Recyling and Reuse of the contaminants will limit the contaminations because its has
significant advantages,it leads to less utilization of raw materials, it
reduces environmental impacts
arising from waste treatment and
disposal .makes the surrounding cleaner
and healthier , it can help us to save a landfill space, can save money,
can reduce the amount of energy required
to manufacturer new products , can also help to prevent the creation of waste at the
sourc
5)
A challenge! Draw a flow chart for
general ways, which can be taken to decrease
contaminants in the sites
visited.
REFERENCE
cfpub.epa.gov/eroe/index.cfm?fuseaction=list
published on 10 March 2011 accessed on January,1th , 2014
,5:12PM
www.epa.gov/air/toxicair/newtoxics.htm accessed on January, 1th
, 2014,5:41PM
