chapter 3 - microorganism & pollution.pdf

7/29/2019 Chapter 3 - Microorganism & Pollution.pdf

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Dr. Ong Meng Chuan

Department of Marine Science

Faculty of Maritime Studies and Marine ScienceUniversiti Malaysia Terengganu



Chapter 3: Microorganism & Pollution

Aquatic Pollution | MMS 3202 2

CHAPTER 3

Microorganism & Pollution

MICROORGANISM : DEFINITION

Organism that is microscopic

Very tiny single celled or unicellular organisms

Include protozoan, bacteria, fungi and protists

Primary producers in marine environments

Found almost everywhere in the world in all living things,

plants and animals

Live in the air, on land, liquid water including hot springs, on

the ocean floor, deep inside rocks in Earth‘s crust

Critical to nutrient recycling in ecosystem as they act as

decomposers

Some organism can also fix nitrogen important part of the

nitrogen cycle

Microorganism that can cause harmful disease are called

PATHOGENIC

Pathogenic microbes can invade other organism and cause

diseases

INTERESTING FACT

Marine Microorganisms Hold the Key to Life on Earth

Few people realize that all life on earth evolved from microorganisms in the sea.

Just one liter of coastal seawater contains up to a million microbes including

thousands of different types.

WHAT ARE THEY?

Microorganisms are essential to all forms of life

There are billions of types of microorganisms that serve as building blocks for all

kinds of ecosystem around the world

Most microorganism are beneficial; they fill important roles such as helping human

digest food, aiding in the proper treatment of wastewater and carrying out functions

necessary to sustain the food chain. These useful microorganism ANTIGENIC





DISTRIBUTION OF MICROORGANISMS IN ENVIRONMENT

Normally they are friendly and low in the aquatic environment at the density of 100

– 1000 cells/mL

The level increases when the environment is polluted

EXAMPLE : 1M – 10M cells/mL in Klang River

o Each day, averagely 50 to 60 tons of solid waste are removed from Klang River

and this has not sum up with the solid waste collected from the solid waste trap

which account for 80 tons

o Pollution – due to high level of organic input and discharge

UMT Mengabang – ??

WHERE DO THEY COME FROM?

Microorganisms such as pathogens may enter aquatic environment through point

and non-point sources, while others may occur naturally

Wildlife, domestic animals and birds may also contribute pathogens to the

environment.

The major sources of bacterial contamination are due to the point source

EXAMPLE

Point source : sewage treatment plant; factory introduce materials directly into the

waterway

Non-point source : heavy metals and oils from streets; sewage from the city;

fertilizer and pesticide from farm All make their way indirectly to the waterway





EXAMPLE : Wastewater treatment

Treatment facilities have greatly reduced the number of pathogens that are release

into aquatic environment through disinfectant processes

Problem : Not always 100% effective and breakdown in facilities sometimes occur

During heavy rains, there is too much water for the sewage treatment plants to

handle, and some untreated or partially treated water maybe disposed into the

aquatic system.

HOW ARE WATERBORNE DISEASE TRANSMITTED TO HUMAN?

Through drinking water – accounts for almost one-third of the illness

Through primary contact – swimming, water skiing, fishing, boating

Through secondary contact – ingestion of contaminated shellfish and fish





HOW ARE PATHOGENS DETECTED?

Measure for fecal coliforms and other sewage indicator bacteria

The presence of bacterial indicators suggest that the water may be contaminated

with untreated sewage and pathogen bacterial may potentially be present A criteria based on the indicator bacteria concentration are used to determine if

waters are safe for human use.

Bacteria from the fecal coliform group are used as indicators because they are not

usually present in unpolluted waters and are easily detected by simple laboratory

procedures.

MICROORGANISM AND BIODEGRADABLE PLASTICS

Biodegradable plastics are those that will decompose in the natural environment

Biodegradable plastics can be achieved by enabling microorganisms in the

environment to metabolize the molecular structure of plastic films to produce an

inerthumus-like material that is less harmful to the environment

ADVANTAGE : proper condition (sun, moisture, oxygen), the plastic degrade to the

point where organism can digest them

Reduce problems with litter and reduces harmful effects on wildlife.

MICROBIAL POLLUTION

Microorganisms may cause pollution

The growth of microorganism may produce undesirable or toxic metabolites

They may produce chemical pollutants which can change the water quality of the

environment

They may contaminated the food-chains

MICROORGANISM METABOLISM

Under aerobic condition :

C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy

Optimum DO in the tropical water is around 8 mg/L

Bacteria





If there is a lot of DO in the water, ammonia (NH3) produced will be converted to

nitrate (NO3–) – which is much less toxic compared to ammonia

If there is not enough DO in the water, ammonia and nitrite which are toxic to

organisms will be accumulated in the water.

NH3 + 3/2 O2 NO2– + H2O + H+

NH3 + 3/2 O2 NO2– + H2O + H+

Under anaerobic condition :

Anaerobic bacteria will use other oxygen-rich substances such as nitrate ( NO 3– ),

sulfate ( SO4

2–

) and carbon dioxide ( CO2 ) as electron acceptors instead of oxygen inthe process of metabolism

These types of reduction process normally carried out in soil contaminated with

high load of organics such as aquaculture ponds

Under this condition, toxic gases such as hydrogen sulfide ( H2S ) and methane ( CH4 )

are produced and they are highly toxic to aquatic organisms

Nitrate reduction

C6H12O6 + NO3– NO2

– + CO2 + …..

Sulfate reduction

C6H12O6 + SO42– H2S + CO2 + …..

Carbon dioxide reduction

C6H12O6 + CO2 CH4 + CO2 + …..

METABOLISM OF NITROGEN COMPOUNDS

Ammonia is produced during the decomposition of organic materials in soil and

water

The safety level of NH3 (gas) to organism is <0.025 mg/L

Nitrate is the end product of microbial breakdown of organic matter in oxygen rich

water.

Nitrate is less toxic compared to NH3

Bacteria

Bacteria

Bacteria

Bacteria

Bacteria





However, if the nitrate reaches beyond 22 ppm, it becomes toxic to organisms and

human.

The disease is known as methaemoglobinaemia which affects the oxygen uptake

system

The permissible level of nitrate in drinking water is less than 10 ppm.

Nitrite is the intermediate byproduct in the oxidation of NH3 to NO3–

It also causes the disease of methaemoglobinaemia Safety level of NO2

– is <0.1 ppm

METABOLISM OF SULFUR COMPOUNDS

Under anaerobic condition, microbial breakdown of sulfur organic compounds

yields H2S

The safety level of H2S ( unionized ) in water is < 3 μg/L

Microorganisms are also capable of producing other volatile sulfur gases such as SO2 and CH3SH ( methyl mercaptan ) which are toxic to organisms.

ACID RAINS





ECOLOGICAL EFFECT

In extreme cases, anaerobic conditions ensue, promoting growth of bacteria such as

Clostridium botulinum that produces toxins deadly to birds and mammals





HARMFUL ALGAL BLOOMS (HABS)

Marine and fresh waters teem with life, much of it microscopic, and most of it

harmless; in fact, it is this microscopic life on which all aquatic life ultimately

depends for food Harmful algal blooms may cause harm through the production of toxins or by their

accumulated biomass, which can affect co-occurring organisms and alter food-web

dynamics

Impacts include human illness and mortality following consumption of or indirect

exposure to HAB toxins, substantial economic losses to coastal communities and

commercial fisheries, and HAB-associated fish, bird and mammal mortalities.

To the human eye, blooms can appear greenish, brown, and even reddish- orange

depending upon the algal species, the aquatic ecosystem, and the concentration of

the organisms





RED TIDE

"Red tide" is a common name for a phenomenon known as an algal bloom, an event

in which estuarine, marine, or fresh water algae accumulate rapidly in the water

column, or "bloom“

These algae, more specifically phytoplankton, are microscopic, single-celled protists,

plant-like organisms that can form dense, visible patches near the water's surface

Not all algal blooms are dense enough to cause water discolouration, and not all

discoloured waters associated with algal blooms are red.

Additionally, red tides are not typically associated with tidal movement of water,

hence the preference among scientists to use the term algal bloom





Certain species of phytoplankton contain photosynthetic pigments that vary in

colour from green to brown to red, and when the algae are present in high

concentrations, the water appears to be discoloured or murky, varying in colour

from purple to almost pink, normally being red or green

Some red tides are associated with the production of natural toxins, depletion of

dissolved oxygen or other harmful impacts, and are generally described as harmful

algal blooms.

The most conspicuous effects of red tides are the associated wildlife mortalities

among marine and coastal species of fish, birds, marine mammals and other

organisms





Assignment 1 : RED TIDE ?

1. Where are RED TIDE found recently in Malaysia and Asia ?

2. What factors cause RED TIDE phenomenon ?

3.

How are RED TIDE harmful ?4. RED TIDE health effect to aquatic organism and human ?

5. How to prevent RED TIDE phenomenon ?

chapter 3 - microorganism & pollution.pdf

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