a comparative assessment on the pollution



a comparative assessment on the pollution
Water covers over 70% of the Earth's surface and is a very important resource for
people and the environment. Water pollution affects drinking water, rivers, lakes and
oceans all over the world. This consequently harms human health and the natural
environment. (Water-pollution, 2003)
Turbidity is a measure of the degree to which the water looses its transparency
due to the presence of suspended particulates. The more total suspended solids in the
water, the murkier it seems and the higher the turbidity. Turbidity is considered as a good
measure of the quality of water.(1998-2009 Lenntech Water treatment & purification
Holding B.V) . The WHO (World Health Organization), establishes that the turbidity of
drinking water shouldn't be more than 5 NTU, and should ideally be below 1 NTU.
The Secchi disk originated with Fr. Pietro Angelo Secchi, an astrophysicist. The
Secchi disk is used to measure how deep a person can see into the water. It is lowered
into the lake by unwinding the waterproof tape to which it is attached and until the
observer loses sight of it. The disk is then raised until it reappears. The depth of the water
where the disk vanishes and reappears is the Secchi disk reading. The depth level reading
on the tape at the surface level of the lake is recorded to the nearest foot. (The secchi
disk- What is it, MLSA-SERVICES)
Figure 1: A secchi disk being lowered
There are several people who did the Secchi disk test already. The following are
some of the recorded Secchi disk reading. The deepest published Secchi disk reading was
80 m on October 13, 1986 in the Weddell Sea, near Antarctica. Perhaps the strangest
unofficial record for shallow Secchi depths should be given to Bob Kortmann, who,
lowering his disk through foam generated by a blue-green die-off, reported a Secchi
depth of minus 5 inches; the disk disappeared before ever reaching the water. (Soil &
Water Conservation Society of Metro Halifax (SWCSMH), July 26, 2006)
It is lowered into the water of a lake or other water body until it becomea
invisible. This depth of disappearance, also known as the Secchi depth, the Secchi disk
reading, the Secchi disk visibility or the Secchi disk transparency (SDT), is a
conventional measure of the transparency of the water. For the measurement of turbidity,
the disk is lowered into the open water by unwinding the waterproof tape or calibrated
line to which the disk is attached and until the observer loses sight of the disk. The disk is
then raised until it reappears. The depth, measured from the water surface to the level
where the disk vanishes and reappears, is the Secchi disk reading. Also, important is the
orientation to the sun, which should be on our back while taking the measurement. To
achieve the best result, the measurement should be taken off the shady side of a boat in
the shadow of our own head lowered on close to the water surface. (Leszek A. Bledzki,
October 15, 2009).
Use a disk of the appropriate size for the clarity range (20 mm for 0.15-0.5 m, 60
mm for 0.5-1.5 m, 200 mm for 1.5-5 m, 600 mm for 5-15 m), painted matte white or in
black and white quadrants. Use a graduated line, and attach a weight to hold the line
vertical. (Some studies found that, in very clear waters, the disk disappeared, not because
of loss of contrast, but because the disk became too small to see. Hence the authors are
suggesting that by changing the size of the disk, the apparent size of the disk when it
disappears would remain approximately the same). Lower the disk on the sunny side of
the boat. underwater viewer (viewscope) is desirable. Allow sufficient time (preferably 2
min) when looking at the disk near its extinction point for the eyes to adapt completely to
the prevailing luminance level. Record the depth at which the disk disappears. Slowly
raise the disk and record its depth of reappearance. The Secchi depth is the average of the
depth of disappearance and reappearance. The readings should be made as near to midday as possible. (Soil & Water Conservation Society of Metro Halifax (SWCSMH), July
26, 2006)
In order that the Secchi Disk measurement be done to provide the greatest
accuracy, the following conditions should be met: The same person should be taking all
readings since sharpness of vision varies from person to person. The reading should be
taken on the same day of the week, or at least not more than one day before or after the
same day of the week. It is preferable that the measurement be taken between 10:00 a.m.
and 4:00 p.m. so that the light rays from the sky are at a similar angle each time the
reading is taken. Avoid taking the measurement when the lake is choppy or rough. (The
secchi disk- What is it, MLSA-SERVICES)
There is a great effect in river of having high turbidity.In Physical Impacts, Fine
sediment can affect the stream channel by:altering the substrate composition, clogging
invertebrates;causing marginal changes to the instream channel morphology, and general
habitat availability;reducing the permeability of the bed material.High suspended
sediment concentrations can also affect water resources by:damaging turbines in
procedures;reducing reservoir and diversion dam storage capacity.Chemical Impacts and
high turbidity levels can cause a decline in the intergravel concentration of dissolved
oxygen (DO).
In biological impacts, an increase in stream water turbidity can cause a reduction
in the depth of light penetration into the water column. This effectively decreases rates of
photosynthetic activity and thus primary productivity in submerged plants (a basic food
source for aquatic animals). A reduction in the food source at the primary level may then
have a knock-on effect upon higher trophic levels.High turbidity levels can also cause
physical damage to leaf surfaces by abrasion and by smothering.High turbidity levels can
adversely affect invertebrate populations, interfere with the behaviour, feeding and
growth of salmonids and other fish species. It can also cause damage to fish gills by
abrasion (hyperplasia), and clogging. Research indicates that fine particles between 23(p.m are mostly responsible for gill abrasion in salmonid populations. High suspended
sediment concentrations may also increase the susceptibility of fish to disease. Mucus
secreted by fish in response to high concentrations of suspended solids attracts bacteria
and fungus. Turbidity can increase surface water temperature and lead to thermal
stratification, a problem not only in rivers, but also for downstream reservoirs and
lakes.Deposition of suspended sediment during high flood events can replenish nutrients
and soil materials on the flood plain. (Rachel Bronsdon, Jonathan Clark, Earth
Sciences Branch, Scottish Natural Heritage).
The suspended particles absorb heat from the sunlight, making turbid waters
become warmer, and so reducing the concentration of oxygen in the water (oxygen
dissolves better in colder water). Some organisms also can’t survive in warmer water.
The suspended particles scatter the light, thus decreasing the photosynthetic activity of
plants and algae, which contributes to lowering the oxygen concentration even more. As
a consequence of the particles settling to the bottom, shallow lakes fill in faster, fish eggs
and insect larvae are covered and suffocated, gill structures get clogged or damaged.
(Lentech, 1993)
pH is a measure of the concentration of hydrogens ions (= H+) (= protons) in a
solution. Solutions with a higher concentration of H+ than occurs in pure water have pH
values below 7 and are acidic.Solutions containing molecules or ions that reduce the
concentration of H+ below that of pure water have pH values above 7 and are basic or
alkaline. The properties of most proteins, enzymes for example, are sensitive to pH.
(Biology pages, August 5 2003). Living organisms must function with narrow range of
pH 6.5-8.5.Higher pH makes ammonia compounds more toxic. Lower pH enable
dissolving of heavy metals if present in the water.Higher pH increase respiratory
efficiency. Lower pH generally indicated lower mineral concentrations (TDS). Ph affects
rates of biochemical reactions. (Raymond RaLonde University of Alaska Fairbanks).
Fresh water sources with a pH below 5.0 or above 9.5 may not be able to sustain plant or
animal species. (center for innovation and science education).
Electrical conductivity is one way to determine the salt content of water.
Electrical conductivity (EC) is measured by passing an electric current between two
metal plates (electrodes) in the water sample and measuring how readily current flows (ie
conducted) between the plates. The more dissolved salt in the water, the stronger the
current flow and the higher the EC. Measurements of EC can be used to give an estimate
of TDS. Electrical conductivity is the measure of total concentration of dissolved salts in
water. When salts dissolve in water, they give off electrically charged ions that conduct
electricity. The more ions in the water, the greater the electrical conductivity it has.
Because there are almost no ions in distilled water, it has almost no electrical
conductivity. Hard water contains more salts, and therefore more ions, has a high
electrical conductivity (electrical conductivity, Shirlie Sharpe ). It is measured by ability
of water to carry an electrical Current. It is the reverse of resistance, the higher ionic
content the better the conductance. It is expressed as microhms/cm of conductance and is
related to pH – Generally high conductivity means high pH. (Raymond RaLonde
University of Alaska Fairbanks).
All substances have properties that we can use to identify them. For example we
can idenify a person by their face, their voice, height, finger prints, DNA etc.. The more
of these properties that we can identify, the better we know the person. In a similar way
matter has properties - and there are many of them. There are two basic types of
called Physical are: color, smell, freezing point, boiling point, melting point, infra-red
spectrum, attraction (paramagnetic) or repulsion (diamagnetic) to magnets, opacity,
viscosity, conductivity, and density. There are many more examples. Note that measuring
each of these properties will not alter the basic nature of the substance.
Examples of chemical properties are: heat of combustion, reactivity with water, pH, and
electromotive force.The more properties we can identify for a substance, the better we
know the nature of that substance. These properties can then help us model the substance
and thus understand how this substance will behave under various conditions.
These are the characteristics that can be oberserved without changeing the substance into
another substance. Melting point, boiling point, odor, color, taste, solubility, density,
hardness, softness, volatility, ductility, malleability, viscosity, physical state, turbidity,
heat conductivity, and electrical conductivity are all physical properties. For example, to
determines the melting point of ice, we must change the ice to water. In this process, the
appearance changes, but there is no change in composition. Water has a boiling point of
100C at sea level where pressure is one atmospheric pressure. It is a clear, colorless
liquid and with a density of about 1g/mL. Pure liquid water does not conduct electricity
and is not a great conductor of heat.
The ability of water to undergo a precess called electrolysis is among its chemical
properties. A change in compisition occures when an electric current is passed through a
cintainter of liquid water (H2O), and the water is broken down to yield the gases
hydrogen (h2) and oxygen (O2). A chemical property is evident when a subtance reacts
with another substance. For example, iron slowly corrodes or rusts when exposed to air or
moist environment to form iron oxide. - The reddish brown rust. It is also a chemical
property if a substance does not react with another substance because it is inert or more
stable than the other subtance. (2011 Hubpages).
Iligan City is bounded on the north by the municipality of Lugait, Misamis
Oriental, to the south by the municipalities of Baloi, Linamon and Tagoloan, Lanao del
Norte, to the east by the territories of Lanao del Sur and Bukidnon, and to the west by
Iligan Bay. This is also the 2nd largest city in Northern Mindanao next to Malaybalay
City.Known as the City of Majestic Waterfalls, there are around 23 waterfalls in and
around Iligan. Among them is the magnificent Maria Cristina Falls, home of Mindanao's
primary hydroelectric power station, and Limunsudan Falls. Iligan is also the Industrial
Center of the South. It produces hydroelectric power for the Mindanao region through the
National Power Corporation (NAPOCOR), the site of the Mindanao Regional Center
(MRC) housing Agus IV, VI and VII hydroelectric plants. It also houses industries like
steel, tinplate, cement and flourmills. The National Steel Corporation, one of the largest
steel manufacturers in the Southeast Asian region, now Global Steelworks International
Incorporated was re-opened in 2003 after heavy setbacks resulting to its closure in 1999.
Iligan along with its neighboring city, Cagayan de Oro City, are the two major
components for the Cagayan de Oro-Iligan Corridor, the fastest developing area in
Northern Mindanao. (Sol Erwin Diaz, July 7 2007)
Figure 4 Map of Tambacan River
Figure 5 Map of Bayug River

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