complete manual.docx

8/10/2019 Complete Manual.docx

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ENVIRONMENTAL ANALYTICAL TECHNIQUES

Lab Manual

Submitted TO

Prof. Dr. Imran Hashmi

Submitted BY

Abid Hameed

IESE NUST

Islamabad


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Some importantlab. safety rules

DO:

.. Assume any unfamiliar substance is hazardous.

Assume that any mixture is as hazardous as its most hazardous component.

Keep only currently needed chemicals in the lab, and restricts lab work to the lab.

Wear assigned protective clothing and equipment.

Wear sturdy shoes that fully cover the feet.

Know where to go and what to do in an emergency.

Know how to use emergency eyewash, safety shower, and fire extinguisher.

Clean up spills and broken glass immediately.

Keep hazardous substances in unbreakable containers.

If breakable containers must be used, keep them in chemical resistant trays.

Carry chemicals in trays or racks, not your hands.

Keep chemicals out of drains, sewers, and general refuse.

Keep hazardous substances in a separate, identified area, ventilated and

away from heat and sun.

Dispose of hazardous substances properly and safely, following small quantity

generator rules if applicable.

Keep food, food containers, or drinking glasses out of areas or refrigerators that

contain chemicals.

Keep storage areas and labs neat and clean.

Wash thoroughly when leaving the lab and before eating, drinking, smoking,

chewing gum, or applying makeup.


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Post signs to warn others of hazards in the lab.

DON'T:

Work alone in the lab.

Eat, drink, smoke, chew gum, or apply makeup in the lab.

Drink from lab glasses.

Sniff or taste chemicals.

Suction with the mouth.

Wear contact lenses.

Wear contaminated clothing outside the lab.

Use damaged glassware.

Store chemicals on hoods, bench tops, or floors.

Leave operating equipment unattended.

Signature: _________________


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Experiment No 1

Title:

Determination of alkalinity ?

Introduction:

Capacity of water to neutralize acid is called alkalinity. There are three types of

alkalinity which can be classified due to the presence of hydroxyl, carbonate and

bicarbonate ions.

i. OH- or caustic alkalinity (due to the presence of OH- ions)

ii. CO3-2

or phenolphthalein alkalinity (due to the presence of CO3-2

ions)

iii. Total alkalinity (due to the presence of HCO3-ions)

Principle of alkalinity is acid base titration in which standard (H2SO4 of 0.02N) acid is

used for titration. Phenolphthalein and methyl orange are used as indicator in this

regard.

Alkalinity of water may be due to the presence of carbonates, hydrogen carbonates,

silicates, borates, phosphates and hydroxyl ions in Free State. The primary source of

alkalinity in drinking water is due to carbonate containing rocks which come from lands

and mountains due to the erosion and weathering processes of rocks. Runoff of water

from agricultural land where lime is also applied contains carbonate which can cause

alkalinity in water. Phosphates and silicates are rarely found in natural supplies in

concentrations significant in the home.

Moderate concentration of alkalinity in water is also desirable so that corrosion of water

pipelines can be prevented and water can be prevented from contamination of copper

and lead because low alkalinity causes corrosion of pipelines. While high alkalinity

produces soda like taste in water. Water with low alkalinity is also not fit for bathing

purpose because it can remove too much oil from skin and causes dryness.

Alkalinity can be removed by reverse osmosis, distillation and softening.


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= 1.2 X .02 X 5000050

= 24mg / L as CaCo3

Methyl Orange Alkalinity = Volume of Acid used X Normality X 50000Ml of sample= 12.72 X .02 X 50000

50= 250 mg / L as CaCo3

Total Alkalinity = Methyl Orange Alkalinity + Phenolphthalein Alkalinity= 250 + 24 = 274 mg / L as CaCo3

[Co3 2-] = 2P= 2 X 24 = 48

[Hco3-] = T2P= 2742(24)= 226

Discussion:

The desirable limit of alkalinity is 200 mg/l whereas permissible limit is 600 mg/l beyond

this limit taste become unpleasant but our sample value is well in range. So our

sample is suitable for use.

References:

http://science.kennesaw.edu/~jdirnber/limno/alkalinity_introduction.pdf

http://freedrinkingwater.com/water-education2/74-alkalinity-water.htm

http://www.ehow.com/facts_5001958_effects-of-alkalinity.html
http://www.ehow.com/facts_5001958_effects-of-alkalinity.htmlhttp://www.ehow.com/facts_5001958_effects-of-alkalinity.htmlhttp://www.ehow.com/facts_5001958_effects-of-alkalinity.html


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Experiment No 2

Title:

Determination of hardness in tap water.

Objectives:

To find out hardness in tap water.

Introduction:

Water having divalent (Ca+2

, Mg+2

, Fe+2

, Mn+2

etc.) and trivalent (Al+3

etc.) cations is

called hard water. Major hardness is due to the presence of Ca+2

and Mg+2

ions. Rain

water is soft naturally but when falls on ground picks up natural hardness minerals like

calcium and magnesium and converts into hard water.

Principle:

Hardness of water is determined by using titrimitric method in which sample is titrated

against chelating agent Ethylene Diamine Tetra Acetic Acid (EDTA) while Eriochrome

Black Tea (EBT) is used as an indicator. Ca+2and Mg+2ions are chelated by EDTA and

complex componds are formed.

Impacts of Hardness (Draw backs):

Hard water causes scaling (CaCO3& Mg(OH)2) in hot water systems, kettles, electric

irons and domestic appliances. Scaling of heating elements shortens their life and

makes appliances less efficient because high fuel/electricity is required to heat them.

Scaling also results the blockage of pipes which may cause huge security hazards.

Ca+2+ 2HCO3- CaCO3+ H2O +CO2


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(scales)

Hard water produces less lather from soap, washing up liquid and washing powders. It

also leaves spots on basins, sinks, baths and toilets.

2C17H35COONa + Ca+2 (C17H35COO)2Ca + 2Na

+

(water soluble) (insoluble ppt)

Health Impacts:

Hard watre is not hazardous for health. Actually, hard water contributes a small amount

of Ca and Mg human dietry needs. In this regard, well known brands of bottled water

supplier maintain hardness of water upto some extant and this characteristic is also

important for the bright appearance of water as well.

Hardness Scale:

A scale is also developed known as hardness scale which is given below:

Hardness Description Hardness mg/l

CaCO3

Soft 0-50

Moderately Soft 50-100

Slightly Hard 100-150

Moderately Hard 150-200

Hard >200

Very Hard >300

Reagents

Standard EDTA solution (0.01M)

Buffer Solution

Eriochrome Black T Indicator

Water Samples


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Procedure

Fill burette with 0.01M STD EDTA.

Add 2ml buffer solutions. Add 2 Drops of Eri-chrome Black T. Red wine color appears if Ca & Mg ions are

present.

Titrate against STD EDTA.

Titrate until blue color appears.

Take 50 ml distilled as blank and proceed as above.

Observations & Calculations

Volume of EDTA used for Tap water Sample

Sr.No Initial reading

ml

Final reading

ml

Volume Used

ml

Mean Volume

ml

1 0 17.5 17.516.32 17.5 33.2 15.7

3 0 16.2 16.2

Mean volume of EDTA used for Tap water sample is 16.3 ml.

Volume of EDTA used for Distilled water Sample


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Pakistan provides maximum limit of 500mg/l as CaCO3for drinking water. So, water is

not hazardous for human health.

Our results show that water is hard.

Reference:

http://dwi.defra.gov.uk/consumers/advice-leaflets/hardness.pdf

http://www.environment.gov.pk/act-rules/DWQStd-MAY2007.pdf

http://www.water-research.net/hardness.htm

National Standards for Drinking Water Quality (NSDWQ), June, 2008, Government of

Pakistan, Pakistan Environmental Protection Agency.


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Experiment No 3

Title:

Determination of Total Chlorine in Water Sample.

Objectives:

Core objective of the analysis is to find out the concentration of total chlorine in water

sample and recommend some mitigation measures to reduce excessive amount of free

chlorine in sample. Importance of free chlorine for disinfection of water will also be

explored.

Introduction:

Chlorine is one of the most widely used disinfectants for water. It is very effective for the

deactivation of pathogenic organisms and makes water fit for human consumption. This

process is also known as chlorination. It is also used for disinfection of pathogens in

swimming pools.

Chlorine forms hypochloric acid on dissolution in water which further dissociates into

HCl and nascent oxygen. Nascent oxygen is a strong oxidizing agent as well as a

disinfectant.

Cl2+ H2O HOCl + HCl

HOCl HCl + [O]

Mainly chlorine gas and hypochlorites (NaOCl and Ca(OCl)2) are used for chlorination in

water.

NaOCl + H2O OCl-+ Na+

Ca(OCl)2+ H2O 2OCl-+ Ca+2

Different forms of chlorine in water:Free Chlorine

Free chlorine may be available in water in three forms at different pH (Cl 2at pH < 5,

HOCl and OCl- at pH 5-8, OCl- at pH > 10). Best pH range for disinfection is 5-6.

Combined Chlorine


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Chlorine combines with organic compounds and forms chlorinated organic compounds

like in the case of alkyl, amine etc. Chloramines are produced when NH3 and

corresponding chloramines react with HOCl.

NH3 + HOCl H2O + NH2Cl (Monochloramine)

NH2Cl+ HOCl H2O + NHCl2 (Dichloramine)

NHCl2 + HOCl H2O + NCl3 (Trichloramine)

Principle:

Total chlorine is determined by using titrimetric method where sample is titrated against

Sodium Thiosulphate (Na2S2O3) of 0.01 Normality. Starch solution is used as an

indicator.

Advantages:

Highly effective against most pathogens.

Provides a residual to protect against recontamination and to reduce bio-film

growth in the distribution system.

Easily applied, controlled, and monitored.

Strong oxidant meeting most pre-oxidation objectives.

Operationally the most reliable.

The most cost-effective disinfectant.

Limitations:

Byproduct formation (THMs, HAAs) which are toxic for aquatic life.

Will oxidize bromide to bromine, forming brominated organic byproducts.

Not effective against Cryptosporidium.

Requires transport and storage of chemicals.


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Reagents

Acetic acid, conc. (glacial).

Potassium iodide, KI, crystals.

Standard Sodium Thiosulfate Solution: 0.01N

Potassium dichromate solution: 0.01N

Starch solution

Standard Iodine Solution

Procedure

1. Take 5 ml of conc. Acetic acid in conical flask.

2. Add one gram of Potassium iodide in a conical flask.

3. Add 100 ml water sample in conical flask yellow or brown color will appear if cl2

is present.

4. Titrate against STD Na2SO3 (0.01M) Solution.

5. Titrate until yellow color becomes light yellow.

6. Add 1 ml of starch solution. The solution will become blue.7. Titrate until blue color disappears. Take total volume of Na2SO3.

Observations & calculations

Total chlorine = (A+B) N35450

Vol of sample


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Titration for sample

Initial reading Final reading Difference

0 1.1 1.1

Titration for blank

Initial reading Final reading Difference

1.1 1.5 0.4

Total chlorine= (1.1+0.4) 0.0135450

100

=5.31 mg/liter

Discussion:

Result from above calculation show that sample contain 5.31 mg/l total chlorine which is

beyond limit as prescribed in National Standards for Drinking Water Quality, Pakistan.

As mentioned in NSDWQ that concentration of chlorine at consumers end should be

0.5-0.2 ppm while at source concentration of chlorine in drinking water should be 1.5-

0.5 ppm. As mentioned earlier, concentration of chlorine in sample is beyond limit so it

has to be lowered within prescribed limits so that no health hazard can occur. For this

purpose aeration has to be done to lower the value of chlorine.


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References:

http://www.lenntech.com/processes/disinfection/chemical/disinfectants-chlorine.htm

http://www.waterandhealth.org/drinkingwater/wp.html

Chemistry for Environmental Engineers by Dr. Ishtiaq A. Qazi

National Standards for Drinking Water Quality (June, 2008), Ministry of Environment,

Pakistan.


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Experiment:

Determination of Total Dissolved and Suspended Solids in Water

Objective

To characterize the water sample with respect to total solids, total dissolved solids andsuspended solids in the given water samples

Introduction

The total dissolved solids are defined as solids that are filterable in nature and are completely

dissolved in water. After evaporation of filterable sample the residue left is termed as Dissolved

Solids.

Suspended Solids are non-filterable in nature and are not dissolved in water. It is residue of

non-filterable sample upon evaporation.

Principle

A properly mixed sample is filtered through a Glass Fiber Filter paper. Filtrate is dried in a

weighted porcelain china dish to constant weight at 179-181 0C in the oven or on the burner.

Weigh the china dish, increase in weight represents the Dissolved Solids.

A properly mixed sample is weighted through a preweighted glass fiber and the residue

retained on filter paper is dried at constant weight 103-105 0C. The increase in the weight of

filter represents the weight of Suspended Solids.

A properly mixed sample is added in pre weighted china dish. It is evaporated in water bathand dried in oven 103-105 0C for one hour. Weigh the china dish, increase in weight represents

Total Solids

Sample Handling and Preservation

Sample preservation is necessary because biological activity will continue after collection of

sample and changes may occur during handling and storage. These things may change the

characteristics of amount of solids.

To avoid the change certain measures are taken which are as follows

Preserving the samples at 40C Do not freeze samples Analysis should be carried out as soon as possible


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Precautions

Water or waste water samples which contain high amount of chlorides, magnesiumor sulfate rapidly absorbs moisture from air. Therefore, samples are kept indesiccators to achieve reasonable constant weight

Samples with high concentration of bicarbonates need additional drying at 180 0C toensure all bicarbonates to carbonates

Prolong drying may lose constituents from samples particularly nitrates or chlorides


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Observations and Calculations

Tabulation for Total Dissolved Solids

Weight of clean porcelain dish (g) W1 (ECTL04) = 56.5855mg/l

Weight of Dish and the residue (g) W2 = 56.6162mg/l

Weight of residue W2 W1 = W= 0.0307mg/l

(W2-W1) * 1000 * 1000/ volume of sample = 614 mg/l

Tabulation for Total Suspended Solids

Weight of clean glass fiber disc (g) W1 = 0.0891mg/l

Weight of filter paper and residue (g) W2 = 0.1069 mg/l

Weight or residue (g) W2 W1 = 0.0178mg/l

(W2-W1) * 1000 *1000 / volume of sample = 356mg/l

Tabulation for Total Solids

Weight of clean porcelain dish (g) W1 (ECTL05) = 55.2180mg/l

Weight of dish and residue (g) W2 = 55.2582mg/l

Weight of residue W2 W1 = W = 0.0402mg/l

(W2-W1) * 1000 * 1000 / volume of sample = 804mg/l


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Discussion

The Total Dissolved Solids of the given sample (614mg/l) is under the permissible limit of the

National Environmental Quality Standards (1000mg/l). There are no available quality

standards for Total Suspended Solids and Total solids in National Environmental Quality

Standards and World Health Organizations. Reliable data on possible health effects associated

with the ingestion of TDS in drinking water are not available. The results of early

epidemiological studies suggest that even low concentrations of TDS in drinking-water may

have beneficial effects, although adverse effects have been reported in two limited

investigations.

Water containing TDS concentrations below 1000 mg/liter is usually acceptable to consumers,

although acceptability may vary according to circumstances. However, the presence of high

levels of TDS in water may be objectionable to consumers owing to the resulting taste and to

excessive scaling in water pipes, heaters, boilers, and household appliances. Water with low

concentration of TDS is also unacceptable for consumers because of its flat and insipid taste

Environmental Significance

Dissolved mineral , gases and organic constituents may produce displeasing taste,odor or color

Dissolved organic chemicals may deplete the dissolved oxygen in receiving waterand may be inert to biological oxidation

High concentration of dissolved solids may produce distress in livestock.

Estimation of total dissolved solids is useful to determine the quality of drinkingwater

Suspended organic solids which are degraded anaerobically may release obnoxiousodor

Biological active suspended solids may include disease causing organisms as well asorganisms such as toxic producing strains of algae

Suspended solids exclude light, thus reducing growth of oxygen producing plants


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References

Hydrology project; World Band and Government of Netherlands funded. 1999. How tomeasure dissolved suspended and total solids. Training module. New Delhi. India

APHA Standard Methods of Examination for water and waste water- 20th Edition.Method 2540 C and 2540 D

Tihansky DP. Economic damages from residential use of mineralized water supply.Water resources research, 1974, 10(2):145

International Organization for Standardization. Water qualitydetermination ofelectrical conductivity. Geneva, 1985 (ISO 7888:1985).


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Determination of Chemical Oxygen Demand

Objective

To determine the organic strength of synthetic waste water sample in terms of COD by

Closed Reflux Method.

Introduction

COD test is widely used to measure the organic strength of domestic & industrial

wastewater [1]. Chemical oxygen demand (COD) is defined as a measure of the oxygen

equivalent of the organic matter content of a sample that is susceptible to oxidation by a

strong chemical oxidant [2]. COD, which can indicate the level of pollution for water

contaminated by reductive pollutants, is the main determinant used to assess organic

pollution in aqueous systems and is one of the most important parameters in water

monitoring.

Observations and Calculations :

Blank Volume of Sample (ml) Volume of FAS used (ml)

2.5 1.4

Synthetic Waste

Water Sample

2.5 0.9

2.5 0.92

2.5 0.9

Mean Volume of FAS used to titrate waste water sample = 0.9 + 0.95 + 0.9 = 0.9

3

COD as mgL-1 O2 = [(A-B) x N x 8000] / Volume of sample (ml)

Where

A = Volume of FAS used to titrate the blank (ml)

B= Volume of FAS used to titrate the sample (ml)


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N= Normality of standardized FAS solution = 0.10 N

COD as mgL-1 of O2 = (1.4 - 0.9) 0.10 8000 / 2.5

COD as mgL-1 of O2 = 160 mg/L

RESULT AND DISCUSSION

According to the Revised National Environmental Quality Standards for Municipal and

Liquid Industrial Effluents Water the COD standard for sewage treatment is 400 mg/L

[3]. Synthetic waste water sample analyzed had a value of 160 mg/ L which is under the

permissible limit of standard. As the result suggest that the COD of waste water sample

is lower than the standard so it is not necessary to be treated. In case the COD value

exceeds the permissible limit of 400 mg l1 then it is necessary to be treated before

discharging it to any water body. The COD value determines the level of organic matter

present which when exceeds the standard limit can cause damage to the aquatic life if

discharged without treatment.

Chemical oxygen demand (COD) is one of the most relevant chemical parameters for

the management of wastewater treatment facilities including the control of the quality of

an effluent. The adequacy of decisions based on COD values relies on the quality of the

measurements. The effect of interfering substances on the determination of COD has

the following aspect. Chloride ions present in waste water cause very high results in the

COD test. As with the standard reflux method, interference occurred because of the

oxidation of some reducible substances, mainly halides, during the digestion. The

difficulties caused by the oxidation of halides can be overcome largely, though not

completely, by complexing with mercury (II) sulfate before refluxing.


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REFERENCES

1- Standard Methods for the Examination of Water and Wastewater. (1989),

American Public Health Association, Washington, DC, 17th Edition, p. 510.

2- Alexandra M.E. Viana da Silva, Ricardo J.N. Bettencourt da Silva, M. Filomena,

G.F.C. Camoes. (2011), Optimization of the determination of chemical oxygen

demand in wastewaters, Analytica Chimica Acta.

3- Revised National Environmental Quality Standards for Municipal and Liquid

Industrial Effluents Water. (1999) Pakistan Environmental Legislation And the

NEQS, Government of Pakistan, p. 4-5.


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BACTERIOLOGICAL EXAMINATION OF WATER BY MEMBRANE

FILTRATION TECHNIQUE

OBJECTIVE

Determination of number of colonies of E.coli present in tap water sample by using Membrane

Filtration Technique.

INTRODUCTION

Escherichia coli, also referred to asE. coli, is a type of fecal coliform bacteria that is found in the

intestines of healthy warm-blooded animals and humans. Most E. coli strains are harmless and

serve a useful function in the body by stopping the growth of harmful bacteria species and by

making necessary vitamins. However, some strains can be opportunistic pathogens, while others

can cause gastrointestinal illness in healthy humans when ingested. An opportunistic pathogen is

an organism that normally lives inside a host without causing injury, but can cause infection in

people with weakened immune systems. E. coli is present in the large intestine, so it will be

present in fecal matter from humans and animals. If recent contamination of water sources with

sewage or animal waste has occurred,E. coli will be present[1]

.

OBSERVATIONS AND CALCULATIONS

Calculate the number of E.coli count (CFU) per 100ml of sample according to the following

general rule.

Total number of E.coli colonies found: 10

E.coli/100ml = Number of E.coli colonies 100

Volume of sample filtered (ml)

= 10 100

100

= 10 E.coli/100 ml


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DISCUSSION

The discharge of municipal wastes is one of the most important water quality issues world-wide

that results in contamination of drinking water. The sewage contains human feces and water

contaminated with these effluents may contain pathogenic organisms which are hazardous tohuman health if used as drinking-water or in food preparation. Fecal contamination of water isroutinely detected by microbiological analysis. For this purpose membrane filter technique is

used for the analysis of water samples. It gives a direct count of total coliforms and fecal

coliforms present in a given sample of water. The organisms used most commonly as indicatororganisms for the detection of the recent contamination are E.coli and coliform group (bacteria

having fecal origin) as whole, as they are easy to detect. By using membrane filtration technique,

10 E.coli colonies per 100ml are found in the tap water sample.

According to National Standards for Drinking Water Quality (NSDWQ) the number of coloniesshould be zero per 100ml of the water so that it could be fit and safe for drinking water

[2].

Similarly World Health Organization (WHO) guidelines give the same standard for drinking

water [3]. It shows that the sample we have tested is not fit for the drinking purpose as it contains10 E.coli per 100ml of water which is far exceeding the standard value. The presence of E.coli in

water sample is a strong indication of recent sewage or animal waste contamination. Some E.colioutbreaks are also caused by some lakes and private wells. These bacteria are capable of causing

illness. The presence of total coliformbacteria may also indicate a breakdown in the treatmentprocess, or growth in the distribution system. So it is important to discover and remove the

source of pollution for safe drinking water purpose. That is why tap water contains chlorine and

has undergone ozone or ultraviolet treatment[4]

.

REFRENCES

1. http://www.safewater.org/PDFS/resourcesknowthefacts/Detailed_Escherichia_Coli.

pdf

2. National Standards for Drinking Water Quality. (2008), Pakistan EnvironmentalProtection Agency (Ministry of Environment), Government of Pakistan.

3. European standards for drinking water, second edition, World Health OrganizationGeneva, 1970.

4. "What Is E. Coli? (Escherichia Coli)." Medical News Today. MediLexicon, Intl., 8 Jun.2011. Web.


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X-ray Fluorescence (XRF) Spectroscopy.

Objective:

Find out the elements present in the soil sample to check the feasibility of soil for plant growth.

Principle:

The sample is irradiated by an intense X-ray beam which knocks out inner shell electrons. Then

outer shell electrons move towards inner shells to fill the vacant space due to which photons of

specific characteristic are emitted known as fluorescent X-rays. Fluorescent X-ray is a

characteristic of the element from which it is emitted.

Observation:

Elements Percentage

Si 66.02

K 3.69

Ca 16.06

Ti 1.34

V 0.036

Cr 0.0425

Mn 0.2478

Fe 12.3651

Rb 0.0373

Sr 0.0572

Zr 0.0866

Discussion:


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There are 16 nutrient elements required to grow plants.

Three essential nutrients carbon, hydrogen and oxygen are taken up from atmospheric carbon

dioxide and water while other 13 nutrients are taken up from the soil and are usually grouped as:

primary nutrients , secondary nutrients , micronutrients

The primary nutrients N, P and potassium K are commonly found in soil. Primary nutrients are

needed in larger amounts by crops, and therefore, are required at higher rates than secondary

nutrients and micronutrients.

The secondary nutrients Ca, Mg and S are required in smaller amounts than the primary

nutrients..

Micronutrients Fe, Mn, Zn, Cu, B and Mo are required in even smaller amounts than secondary

nutrients.

Elemental analysis of soil sample shows that this soil sample dont have phosphorus (P) and

nitrogen (N) and only primary nutrient present is potassium (K) having 3.69% While, among

secondary plant nutrients Ca (16%) is present but not in sufficient amount. This shows that this

soil sample is deficient of primary and secondary plant nutrients. To grow plants or crops somefertilizers (having these nutrients) has to apply on this soil.

References:

Libranza, A. K. (2012). SOIL and LEAF Sampling and Analysis more.

M. Ray Tucker, (October, 1999), Essential Plant Nutrients.

Tandon, H. L. S. (2005).Methods of analysis of soils, plants, waters, fertilisers & organic

manures. Fertiliser Development and Consultation Organisation.


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