MIC 303INDUSTRIAL AND ENVIRONMENTAL MICROBIOLOGY

CHAPTER 9-WATER POLLUTION

Microbial Water Pollution

• Primary interest is microbial population, pathogenic organisms.

• Some pathogens are transmitted to humans in drinking and recreational water.

• Two sources of water pollution:1)Biological Pollution.2)Chemical Pollution.

Biological Pollution

• Microbes are filtered from water that percolates into groundwater.

• Generally, water from springs and deep wells is good quality.

• Pollution occurs when feces enter the water supply, in which a pathogen is shed in human and animal feces.

Chemical Pollution• Sources of Pollution:1)Industrial and Agriculture chemicals

leached from the land to water sources. resistant to biodegradation and may be

concentrated in the aquatic food chain. E.g.: Mercury from paper manufacturing

was allowed to flow into waterways as waste, remain seggregated in the sediments.

Bacteria in sediments converted mercury into methyl mercury (soluble chemical compound) which then taken up by fish and invertebrates in the waters.

Chemical Pollution (con’t)

2) Municipal waste containing detergents, main sources of phosphates in lakes and streams.

Phosphates can lead to ‘eutrophication’ (caused by an overabundance of nutrients in lakes and streams)

Caused in a dense aquatic growths called ‘algal blooms’.

Many cyanobacteria only requires a traces of phosphorus to initiate blooms.

Another effects of eutrophication: Red tides of toxin-producing phytoplankton ingested by seafood, especially clams or similar mollusks and become toxic to humans.

ALGAL BLOOMS

Accumulated phosphates cause “algal blooms”.The blooms supply nutrients to other microbes, which use up oxygen. Aquatic animals and plants die.They accumulate on the bottom where anaerobic bacteria thrive.

Diatom (Bacillariophyta)

Dinoflagellates (Pyrrophyta)

Anabaena sp (Cyanobacteria)

Euglena sp (Euglenophyta)

Common phytoplankton causing a water pollution

Porphyra sp(Rhodophyta)

Bactrachospermum sp

(Rhodophyta)

ALGAL BLOOMS

Algal bloom in OrieltonLagoon, Tasmania,

Australia,1994

Red algal bloom at Leigh,near Cape Rodney, New Zealand, 2004

ANALYTICAL METHODS TO ASSESS THE

STRENGTH OF WATER

POLLUTION

INDICATORS OF WATER POLLUTION

• Chemical• Biological• Physical

CHEMICAL INDICATORS• Total Dissolved Solid• Alkalinity• Water Hardness• Toxic Metals• Organics• Nutrient

CHEMICAL INDICATORS

Total Dissolved Solid

• the material remaining in water after filtration and evaporation of water.

• Sources of TDS:Dissolved material result from solvent

action of water; solid, liquid, gasesous.Dissolved substances may be organic/

inorganic matter. Inorganic – metal, material, water and

gaseous.Organic – may come from decaying/

decayed vegetation atmosphere, organic chemical or gaseous.

Impact of TDS:Most TDS value undesirable in water as give

rise to odor, colours and some may be carcinogenic.

Some maybe toxic such as halogen groups which may combine to give organic complexes and cause skin allergic.

Measured of TDS:Filter sample of fixed volume of water and

evaporated to dryness resultant rate residue. Express in mg/L.

Organic and Inorganic fraction of TDS can be analysed by Atomic Adsorption Sectroscopy (AAS) or HPLC technique.

Used of TDS value:To give broad measurement of dissolve

materials in natural water and waste water.Major metallic ion presence, commonly in

natural water.

Examples of constituents:Major constituents (1-100 mg/L): Ca, Na, Mg,

Bicarbonate, Sulfate chloride.Secondary contituents (0.1-10.0 mg/L): Irons,

Potassium, Nitrate, Boron, Silicon, Fluoride.

Alkalinity• Defined as quantity of ions in water that reach to

neutralize H2 ions or measured of the ability of water to neutralize acids.

• Sources: Constituents in natural water – carbonate, bicarbonate,

hydroxide, HSO3, H2BO3, HPO4, H2PO4, H2S, NH3.

This constituent result of dissolution mineral/ substances in soil and atmosphere.

Phosphate originate from detergent, waste water of fertilizer.

H2SO4 and ammonia product of decomposition of organic materials by microbes.

Most common constituents is HCO3 and CO3 and htydroxide which originate from atmospheric CO2 and organic material compound.

Impact of alkalinity:Can cause a bitter taste in water if large

quantity applied.High alkalinity result of precipitation of

calcium carbonate and fauling water pipes.

Measurement of alkalinity:Perform by titration of water with acid and

determining hydrogen requirement.Express as mg/L of calcium carbonate.

Uses of alkalinity:To determine natural water buffering

capacity.As process control variable for water and

waste treatment system.

Water Hardness• Concentration of multivalent metallic cation in solution at

supersaturated condition.• The hardness cation will react with anion in water to form

precipitate.• Classified as carbonic hardness and non carbonic

hardeness depend on anion which associated with hardness equivalent.

• Carbonic hardness sensitive to heat and precipitate readily and higher temperature.

• Sources of TDS: Dissolved material result from solvent action of water;

solid, liquid, gasesous. Dissolved substances may be organic/ inorganic matter. Inorganic – metal, material, water and gaseous. Organic – may come from decaying/ decayed vegetation

atmosphere, organic chemical or gaseous.

Sources of water hardness: Multivalent metallic cation abundance in natural

water. Ex: In reduced form → Calcium, Mg, Fe, Mn.

Impact of hardness: Increase consumption of soap by users lead to

economic losses. Most soap react with multivalent metallic ion

formed precipitate where loosen. Precipitate cause stains on cloths, clog up pipes.

Measurement of hardness: Using spectrophotometic technique or simple

chemical titration. If titration technique used, often use EDTA.

To determine quantity of Ca & Mg ion in water sample.

Toxic metal

• Harmfull to human and aquatic flora in small quantity.

• Dissolved in water. Ex: Arsenic, Barium, Cadmium, Lead, Mercury, Silver.

• Normally accumulate in food chain and posed greatest danger in life.

Organics constituents

• Divided into:Natural (decay of organic material in

nature).Synthetic (waste water discharge or

agricultural activity).

• Soluble in water and comes from natural source of human activity.

• Dissolved organic:Biodegradable organic.Non- biodegradable organic.

1) Biodegradable organic

• Organic material, in dissolved form can be utilize as food by microorganisms.

• Consist of starch, fat, protein, alcohol, acids, aldehyde and ester.

• There maybe end product of initial microbial decomposition of plant/ animal tissue/ may be result of organic waste water → can cause colour and taste problems to consumers.

• Biochemical Oxygen Demand (BOD) is used to determine the amount of oxygen needed to either biologically or chemically oxidize the polluting material present in waste water.

The test indicates: The oxygen utilized during a specified

incubation period for the biochemical degradation of organic material

The oxygen used to oxidize inorganic material such as sulfides and ferrous iron.

Measurement: BOD – amount of O2 consumed during

microbial utilization of organic. BOD measured by determine O2 consumed

in sample air tight containers and capped in control environment for 5 periods of days in 250-300 ml brown bottle – to exclude light (if algae present, will not affected the result).

Diluted sample is calculated by:DOi – DOf

P where;

Doi : Initial [O2]

Dof : Final [O2]

P : Decimal volumetric fraction of sample used.

2) Non- Biodegradable organic• Organic material resistant to microbial

degradation or slow to be degrade.• Ex: Tannin, lignin, cellulose, phenol,

alkylbenzene sulfonite (ABS).• Being the surfactant, ABS cause frothing

and forming in waste-treatment plant, it is non-degradable.

• Chemical Oxygen Demand (COD) determines the amount of oxygen required to chemically oxidize any oxidizable material present in a waste water such as ammonia and nitrite.

2) Non- Biodegradable organic

• Measurent:Determine their chemical oxygen demand (COD)

or total organic carbon (TOC) content.used to indirectly measure the amount of organic

compound in water.determine the amount of organic pollutants

found in surface water (e.g. lakes and rivers),expressed in milligrams per liter (mg/L), which

indicates the mass of oxygen consumed per liter of solution.

COD and TOC measure biodegradable portion of organic. Therefore, BOD is a substrate from COD or TOC → to quantity non-biodegradable portion.

Nutrient• Main: Carbon, nitrogen, Phosphorus • Most these nutrient derived from decomposition

animal and plant from atmosphere through electrical discharge/ lihtening reaction.

• Other sources:Waste water discharge.Chemical fertilizer ran off.

• Over fertilization by chemical fertilizer (nitrogenous compound) result in discharge nitrate in the H2O wastes → give rise in algal bloom (eutrophication).

BIOLOGICAL INDICATORS

Biological Water Quality1) PATHOGEN• The occurance in fresh water system, important in

biological parameters influence water quality.• Pathogenic microorganisms:

not native in aquatic system and usually require animal host for growth and reproduction.

Can be transported by natural water system and can live in these habitat.

Can survive in water and maintain infectious capability for significant period of time.

2) WATER BORNE DISEASES

Ex: Cholera, diptheria

Biological Water Quality

3) PATHOGEN INDICATOR• The procedure for total coliform count.• These occurance pathogen microorganisms in

water capable of infecting and transmitting disease is most important biological parameter influencing water quality.

• To identify pathogen in fresh water is a very expensive process.

• Usage of indicator organisms is best approach to check biological activity.

• Indicator organisms is first present in water system, presumed contamination occur.

Biological Water Quality

3) PATHOGEN INDICATOR (CON’T)• Ideal indicator organisms/ pathogen indicator:

Applicable in all type of waterAlways present when other pathogen present.Always absence when other pathogen absence.Lane itself to routine quantitative procedure

(allow itself)Most water borne pathogen introduced to water via faecal contamination.Indicator pathogen which poses all characteristics belongs to coliform groups.

• Measurement of Faecal Coliform.

Biological Water Quality

4)MEASUREMENT OF FAECAL COLIFORM• Membrane filtration technique.• 100 ml sample of water filtered

through 0.22 µl sterile membrane filter and placing on selective media, incubated at specific incubation temperature.

• Colonies found expressed as cfu/ 100 ml of water sample.

• Alternative method is Multiple tube fermentaion technique.

WATER PURITY TEST

Water Purity TestsPresence of indicator organisms shows that water has been contaminated by feces.

Coliform bacteria live in mammalian intestines, but can survive in water.

The membrane filter technique and standard plate count are used to determine numbers of bacteria in a water sample.

The most probable number test determines number of bacteria by observing carbon dioxide gas production.

The ONPG and MUG Coliform Test

• Aerobic or facultatively anaerobic, gram-negative, non–endospore forming rods that ferment lactose to acid plus gas within 48 hours, at 35°C.

• ONPG causes E. coli to make -galactosidase.

MUGfluorescent compound

- galactosidase

Multiple-Tube Method

Membrane Filtration Method

WATER-BORNE

DISEASES

Physical pollution occurs when sand and soil or cyanobacterial blooms cloud the water.Chemical pollution occurs when inorganic and organic waste enter the water.Biological pollution occurs when microorganisms enter the water from anthropogenic sources.

Cause a water borne diseases

Types of Water Pollution

Diseases spread by contaminated water consumption include:• typhoid fever• cholera• shigellosis • Legionnaires’ disease

Erysipeloid is an infection caused by the marine pathogen Erysipelothrix rhusiopathiae

Diseases Transmitted by Water

Mycobacterium marinum can cause a lesion (granuloma) at the sight of a wound

Vibrio vulnificus can cause:

intestinal illness if consumedwound infections involving gangrene and necrotizing fasciitis

Viruses like: hepatitis A rotavirus gastroenteritis polio virus

Eukaryotic microorganisms like: Entamoeba histolytica Giardia lamblia Crytosporidium

Toxin-producing dinoflagellates which cause ciguatera poisoning in humans. For example, Gambierdiscus toxicus

Water can also transmit

Other Syndrome

Excessive nitrates also causes nitrate poisoning in animal and human.In human, nitrate poisoning heve been refered as “Blue baby syndrome”, cause blood poisoning and death.High nitrate in water may result in low blood pH → resulting in conversion of blood nitrite to blood nitrate (NO3 to NO2).

Nitrate in blood is strong affinity to haemoglobin than O2 and the victim suffered lack of O2.