МІНІСТЕРСТВО ОСВІТИ І НАУКИ УКРАЇНИ

ХМЕЛЬНИЦЬКИЙ НАЦІОНАЛЬНИЙ УНІВЕРСИТЕТ

Ковтун І.І.

ОСНОВИ ЕКОЛОГІЇ ТА БЕЗПЕКА ЖИТТЄДІЯЛЬНОСТІ

Конспект лекцій

ECOLOGY AND SAFETY

Lectures

Хмельницький 2008

Основи екології та безпека життєдіяльності: конспект лекцій /І.І. Ковтун. –

Хмельницький: ХНУ. – 2008.

Затверджено на засіданні кафедри БЖД

Протокол № 1 від 11 вересня 2008 р.

В конспекті лекцій розглянуто основні питання стосовно аспектів

безпека і екологічність в системі “людина - навколишнє середовище“ з

метою забезпечити відповідні сучасним вимогам знання студентів про

загальні закономірності виникнення і розвитку небезпек, надзвичайних

ситуацій, в першу чергу техногенного характеру, їх властивості, можливий

вплив на життя і здоров’я людини та сформувати необхідні в майбутній

практичній діяльності спеціаліста уміння і навички для їх запобігання і

ліквідації, захисту людей та навколишнього середовища. Конспект лекцій

підготовлений на англійській мові і призначений для студентів напряму

підготовки 0304 “Міжнародні відносини”.

Introduction

Ecology and safety is scientific and practical course that studies aspects

of safety and ecology in interactions between organisms and their natural

environment.

Purpose of the course: providing students with appropriate to modern life

knowledge of hazards, emergencies, their characteristics and possible biological

effects, practical risk management and protection of environment.

Objectives of the course: studying sources of environment contamination

and its health effect; learning practical environmental protection and safety in

emergency situations.

Subject: safety and ecology in interactions between people and their natural

environment.

At completion of the reading students will have knowledge of:

ecology and safety terms;

characteristics of environment and its contamination;

procedure of risk management;

emergency management;

provision of a first aid service;

properties of protective equipment.

At the end of this course students will be able to:

assess contamination of environment;

identify potential hazards, their type, intensity, source and location;

assess the risk of an accident, its likelihood, consequences and rating;

apply the risk controls to improve level of industrial safety and ecology;

use personal protective equipment and equipment to protect personnel and

people from technical accidents and natural disasters .

Chapter 1 - THEORY OF ECOLOGY

1. ECOLOGY TERMS

Ecosystem (biogeocenosis): a system involving the interactions between a

community and its non-living environment.

Biogeocenosis includes biotope and biocenosis.

Biotope: a small area that supports its own distinctive community.

Biocenosis: a diverse community inhabiting a single biotope.

Ecological factors: any environmental condition able to produce direct or

indirect effect on community and its interaction.

They are:

- abiotic – influence of non-living environment;

- biotic – action of living organisms;

- anthropogenic – man’s impact;

- technogenic – industrial impact.

2. ECOLOGY LAWS

Ecology axioms of Commoner:

- everything is interconnected;

- everything should get somewhere;

- nothing comes for free;

- nature knows better.

Multitude law: many occasional factors produce result, which is not

assumed occasional.

Correlation law: all parts of one organism are interconnected, that’s why

changes in one part cause changes in the others.

Le-Shatelie – Braun principle: if system is exposed to external factor, that

takes it to imbalance, balance tends to condition reducing effect of external factor.

Law of minimum (the first law in history of ecology): living potential is

limited by that environmental factor which is in minimum.

Tolerance law: adds law of minimum and asserts that both minimum and

maximum of environmental factors could be limiting.

Diapason between minimum and maximum defines zone of optimum.

3. NATURAL ENVIRONMENT

Environment: totality that includes four components: atmosphere,

hydrosphere, lithosphere and biosphere.

Atmosphere: the gaseous envelope surrounding the earth and reaches about

3000 km from the earth surface. Modern atmosphere consists of: 78.1% nitrogen,

20.93 % oxygen, 0.08% argon, 0.027% carbon dioxide, and additionally it contains

helium, neon, xenon, krypton, hydrogen, ozone, ammonia etc.

Hydrosphere: the watery part of the earth's surface, including oceans, lakes,

water vapor in the atmosphere, etc (fig. 1).

Earth waters

4%

96%

Salt water

0.02% rivers, lakes, bogs

29.98%

Underground

70%

Ice

Fig. 1 Earth waters chart

Lithosphere: the rigid outer layer of the earth, having an average thickness

of about 75 km and comprising the earth's crust and the solid part of the mantle.

99.5 % of earth's crust are made from 8 components: oxygen, silicium¸ hydrogen,

aluminum, iron, magnesium, calcium, sodium. Amount of oxygen and silicium

makes 75 % of the total.

The top layer of the land surface of the earth that is composed of

disintegrated rock particles, humus, water, and air is soil.

Biosphere: the part of the earth's surface and atmosphere inhabited by

living things. The upper limit of biosphere reaches 20-25 km height to the lower

boundary of ozone layer. And its lower limit lays at 23 km depth from dry land

(bacteria in oil layer) and 1-2 km lower ocean bottom.

The highest achievement of biosphere development advanced by mankind

became forming the sphere of mind, civilization – noosphere.

4. CLASSIFICATION OF NATURAL RESOURCES

The concept «environment» includes all natural elements, and also part of

nature changed by people activity (settlements, agricultural areas, reservoirs and

others). By natural resources we understand objects, conditions and processes,

which are used or can be used in manufacturing for sufficing material, scientific

and cultural needs of society.

The natural resources are divided into exhaustible and inexhaustible.

Inexhaustible natural resources include space (solar radiation and energy

of marine flows and waves) and climatic (wind power and Earth bowels) power

resources. Taking into account huge masses of air and water medium of the planet

atmospheric air and water resources can be referred to inexhaustible resources too.

But such reference is conditional, cause chemical structure and physical condition

of atmosphere and hydrosphere get changed under people activity influence

(anthropogenous influence) what can bring to losses of their biological value and

possibilities of using. That makes necessary to execute a complex of works on

supporting air and water purity.

Exhaustible resources in turn include renewable and nonrenewable natural

resources. The renewable resources can be recreated during their using. The

renewing goes at various velocity: formation of 1 cm of humus ground layer

takes about 600 years, growing of cut down wood - dozens of years, animals’

population - up to 10 years. Thus, the rate of renewed resources using should be

in balance with rate of their restoring. Nonrenewable natural resources are those

which can’t be renewed absolutely or their renewing goes slower than their using.

Minerals which using entails overcrop refer to such resources. Their protection

should consist in economic, rational and complex using so resources will have a

minimum loss. Besides, nonrenewable resource is the space people live in.

5. ECOLOGICAL STANDARDIZATION

The main goal of ecological standardization is to identify all potential

contaminants of environment and find exposure standards for them.

Exposure standards provide us with limits of acceptable concentrations.

THRESHOLD LIMIT VALUE (TLV) refers to maximal concentrations of

substances to which it is believed that nearly all people may be repeatedly exposed

day after day without adverse effect.

More detailed information about TLVs is introduced in further chapter on

airborne contamination.

LIMITS OF ACCEPTABLE EMISSION: limit concentration of

contaminants in the air for some period that shouldn’t exceed TLV within control

area.

CONTROL AREA: territory surrounding enterprise that prevents harmful

emissions from contaminating environment or at least reduces them.

Control areas are divided into 5 classes:

1 – 1000 m (chemical and refinery plants);

2 – 500 m (production of concrete, lime carbonate);

3 – 300 m (thermal power station, ferroconcrete plants);

4 – 100 m (electronic and machine building plants);

5 – 50 m (light and food industry plants).

Compliance of air quality with standards is checked by assessing

concentration of harmful substances against their exposure standards.

Acceptable condition is C ≤ Cst.

In case of presence of several contaminants which action is reinforced by

each other acceptable condition will be:

C

C1

C

+ 2 + ... + N ≤ 1.

C st 1 C st 2

C st n

6. CLASSIFICATION OF ENVIRONMENT CONTAMINATION

Pollution of environment: entry of potentially dangerous components which

destroy or reduce productivity of ecosystem.

Pollution is classified as natural and anthropogenic.

Natural pollution is caused by disasters (volcano eruption, mud and stone

flow). Its rating doesn’t change significantly.

Anthropogenic pollution is localized near people activity and has stable

spots of high concentration pollutants. It can be mechanical, physical, chemical

and biological.

Mechanical pollution: with agents which can’t have physical or chemical

reactions.

Physical pollution is divided into thermal (that changes temperature), light

(that changes natural illumination, what in turn changes tempo of plants and

animals), electromagnetic (that causes changes in biological tissues), radiation (that

has ionizing effect).

Chemical pollution changes average concentration of any substance or entry

of substances which had been naturally absent.

Biological pollution is appearing of extremely amount of microorganisms.

Chapter 2 - ENVIRONMENTAL PROTECTION

7. AIRBORNE CONTAMINATION

An airborne contaminant is a potentially harmful substance that is either

naturally absent from air or is present in an unnaturally high concentration, and to

which people may be exposed in their environment.

The uptake of airborne contaminants occurs throughout the respiratory

system, digestive organs, skin and mucous membrane.

The dominant driving force in the uptake of gases, vapors and dust is in

respiratory system, liquid substances – through the skin. Contaminants get into

alimentary tract while swallowing due to dirty hands.

CLASSIFYING HAZARDOUS SUBSTANCES:

1. toxic – substances which cause acute lethal effects, irreversible health effects

such as damage to the central nervous system, kidneys or liver, or which cause

anemia or paralysis after a single dose, may be classified as very toxic, toxic

or harmful (carbon monoxide, lead, mercury);

2. irritant – a substance that causes inflammation of the skin, eye irritation,

serious eye problems or irritation to the respiratory system (chlorine, acetone,

ozone, formaldehyde , phosgene and nitrogen oxides, sulphur oxides;.

3. sensitizer – a substance that causes a substantial proportion of people exposed

to develop an allergic reaction after repeated exposure to the substance

(formaldehyde: used as formalin and in the manufacture of synthetic resin,

various lacquers, solvents);

4. carcinogenic – any substance that produces cancer (nickel and its compounds,

asbestos, chrome oxide);

5. mutagenic – a substance or agent that can induce genetic mutation (lead,

manganese, radioactive substances);

6. teratogenic – any substance that causes malformations in a fetus (mercury,

lead, manganese, radioactive substances).

Dusts are solid particles generated and dispersed into the air by, for example,

handling, crushing and grinding of organic or inorganic materials such as rock,

ore, metal, coal, wood and grain.

The health effects caused by particulate exposure are equally diverse.

Skin contact with some dusts, such as organic dusts from flour and grains,

may cause irritation or allergic responses in sensitized persons, while inhalation of

other organic dusts, particularly some wood dusts, has been shown to cause nasal

cancer in heavily exposed workers. However, the major health effects are usually

found in the lungs

The mixture of dust and air makes dispersion, where air is dispersion media

and dust is dispersed fraction.

Dispersion classifies dusts by particle size:

- inhalable dust has a 50% cut-point of 100 microns (10 < d ≤ 100 microns);

- thoracic dust has a 50% cut-point of 10 microns (5 < d ≤ 10 microns);

- respirable (smoke) dust has a 50% cut-point of 5 microns (d ≤ 5 microns);

that dust is so small in size that it can get through the lung defense

mechanisms of the human body and get down deep into the gas exchange

(alveolar) region of the lung.

Known biological effects:

- silicosis, which results from exposure to silica;

- other lung reactions include bronchitis – inflammation of the bronchi;

- asthma, which is a constriction of the bronchial tubes; and

- cancer;

- restricted lung function can place burden on the right side of the heart and

this additional stress can result in irreversible heart damage over time.

8. MEASURING AIRBORNE CONCENTRATIONS AND AIR

PROTECTION

Personal exposures are measured in the breathing zone of the worker.

Breathing zone: is described by a hemisphere of 300 mm radius extending

in front of a worker's face and measured from the midpoint of an imaginary line

joining the ears.

There are two general types of sampling techniques:

- active Sampling: using pump;

- passive Sampling: no pump.

There are three key elements of active sampling:

- a sampling pump - something to pull or push air;

- the sampling media - something to pull or push air through;

- a calibrator - something to indicate how much air has been pulled or pushed.

A variety of sampling media is used in sampling for gases and vapours:

- sorbent tubes;

- filters;

- impingers: are specially designed glass bottles that are filled with a

collection liquid specified in the sampling method for specific chemicals;

- sampling bags;

- passive samplers: the collection of airborne gases and vapours at a rate

controlled by a physical process such as diffusion through a static air layer

or permeation through a membrane WITHOUT the active movement of air

through an air sampling pump.

Requirements for sampling instruments are:

- to detect airborne contaminant at least at concentration a half of exposure

standard in exhaust air;

- and the third of exposure standard in influx air;

- acceptable error is ±25% of measured value.

Airborne contaminants may force to have either antagonistic or synergistic

effects.

In first case they are of multidirectional action, in the second –

unidirectional. Those types should be considered for assessing concentrations

against the standards.

Acceptable condition for multidirectional hazards C1≤TWA1, C2≤TWA2...

Acceptable condition for unidirectional ones

Atmospheric air can be referred to inexhaustible resources. However air

protection takes an important place in ecology and offers variety of purification

methods.

Purification from dust: dust catchers «dry» and scrubbers «wet».

Purification from gases: absorption methods, adsorption methods.

Absorption methods remove airborne contaminants by the liquid.

In absorber gas and liquid move contraflow what’s followed by chemical

reaction.

Absorbers advantages: simple, reliable and have high degree of purification.

Disadvantages: cumbersome equipment, salvaging wastes.

Adsorption methods trap airborne chemicals on the surface of solid bodies

(sorbents).

Adsorbers advantages: no chemical reaction, adsorbed gases and sorbent can

be recycled.

Practice:

Assess the given concentrations of airborne contaminants: 10 mg/m3

of white spirit and 0.01 mg/m3 of lead, which make a group of unidirectional

contaminants, and; 50 mg/m3 of gasoline.

9. EXPOSURE STANDARDS

THRESHOLD LIMIT VALUE (TLV) refers to airborne concentrations

of substances to which it is believed that nearly all workers may be repeatedly

exposed day after day without adverse effect.

There are three categories of exposure standards:

- 8-hour time-weighted averages (TWAs);

- Short-Term Exposure Limits (STELs);

- Peak Limitations or Ceiling Values.

8-HOUR TIME-WEIGHTED AVERAGES (TWAs): average airborne

concentration of a particular substance when calculated over a normal eight-hour

working day, for a five-day working week.

8-Hour TWA exposures are calculated as follows:

CN

C1

C2

+

+ ... +

≤ 1.

TWA1 TWA2

TWAN

C1T1 + C 2 T2 + * + C n Tn

8

,

TWA =

where: C - concentration of contaminant; and T - incremental exposure time.

SHORT TERM EXPOSURE LIMITS (STELs): exposures at the STEL

should not be longer than 15 minutes and should not be repeated more than four

times per day. There should be at least 60 minutes between successive exposures at

the STEL.

It is to avoid both acute and chronic health effects.

Some substances can cause intolerable irritation or other acute effects upon

brief overexposure, although the primary toxic effects may be due to long-term

exposure through accumulation of substances in the body or through gradual health

impairment with repeated exposures. Under these circumstances, exposure should

be controlled not to exceed STEL to avoid both acute and chronic health effects.

PEAK LIMITATIONS OR CEILING VALUES: concentrations that should

not be exceeded even for an instant during any part of the workday.

For some rapidly acting gases or vapors, the averaging of the airborne

concentration over an eight-hour period is inappropriate.

These substances may induce acute effects after relatively brief exposure to

high concentrations and so the exposure standard for these substances represents

a maximum or peak concentration to which workers may be exposed. Examples

of gases or vapours with peak limitation exposure standards are hydrogen

fluoride, acetic anhydride, n-butyl alcohol, chlorine, ethyl acrylate, ozone and

glutaraldehyde.

Airborne contaminants are classified into 4 classes by their TWA:

1. 1st class – extremely hazardous substances with TWA less 0.1 mg/m3 (lead,

mercury, ozone);

2. 2nd class – highly hazardous substances with TWA within 0.1 - 1.0 mg/m3

(sulfuric and hydrochloric acid, chlorine, phenol);

3. 3rd class – medium hazardous substances with TWA within 1.1 - 10.0 mg/m3

(toluene, methyl spirit);

4. 4th class – low hazardous substances with TWA greater 10 mg/m3 (ammonia,

gasoline, acetone).

Standard may have a letter that points effect to be produced by contaminant

being exposed to the person, for example “O” – acute effect; “A” – allergic

effect; “K” – carcinogenic effect; “F”- fibrotic effect.

10. WATER POLLUTION AND PROTECTION

Economics in relation to the water resource can be either consumer or user.

Consumer: takes water from a source, uses it for needs of production and

returns it but in the other place, less quantity and different quality.

User: doesn’t take water from a source, but uses it as media (shipping,

fishing, sport) or source of energy (hydro-power stations). However they change

water quality also.

Water pollution is classified as:

Chemical pollution: is caused by harmful non-organic (acids, alkaline,

mineral saline) or organic (oil, oil-products, surface active substances, washers,

pesticides) substances incoming to water surface layers. Most of non-organic

substances are toxic for community inhabiting waters (compounds of arsenic, lead,

mercury, copper, cadmium, chromium, fluorine). They are absorbed by plankton

and then transmitted through feed links to other organisms. It’s accompanied by

cumulative effect that 10 times increases amount of harmful compounds in every

next feed link. Metal manufacture, mineral resource industry, chemical industry,

agriculture (fertilizers) are the main sources of mineral pollution. Sewages of

chemical plants contain great quantity of organic compounds. Most of synthetic

washers contain phosphorus. Increased quantity of phosphates in sewages causes

intensive growing of blue-green water plants - water “blossom” what lowers

oxygen in water and kills water animals.

Physical pollution: changes physical characteristics of water – clarity,

contents of suspension and insoluble agents, radioactivity. Power stations emitting

thermal waters are sources of thermal pollution (especially Nuclear Power Stations,

t = 45 deg C).

Biological pollution: is caused by microorganisms incoming to water

through sewages (virus, bacteria, fungus, protist). Biological pollution is examined

by the following parameters:

1. “koli-index”: quantity of intestinal bacillus in 1 Liter of water (TLV = 3);

2. biochemical oxygen consumption (BOC): amount of oxygen needed to

decompose organic substances into inorganic (BOC TLV = 3 mg/l in potable

water within 5 days).

Water protection:

1. recycling;

2. wasteless technologies;

3. burying sewages;

4. purifying water;

5. reducing use of chemicals in agriculture;

6. imroving tankers.

11. MONITORING WATER POLLUTION

To provide normal life activity of the human’s organism it’s important to

know the concentration of harmful substance in solutions (for example in sewage).

This is the photoelectric method of quantitative analysis based on capability of

the investigated substance to absorb the electromagnetic waves in optical range

applied for.

Colorimetry is one of the photometric methods of analysis. The essence of

the method consists in coloring a component (if it was colorless) and determining

its concentration by the quantity of light it absorbs.

The main law of colorimetry - Bouger-Lambert-Behr law states dependence

between luminous flux a solution absorbs and concentration of a substance which

absorbs the light in it:

,

(3)

where , - intensities of the luminous flux falling on solution and passed through

the solution with thickness correspondingly, - molar coefficient of light-absorbing,

or extinction, which doesn’t depend on concentration of investigated substance,

but depends on its nature, wavelength of the luminous flux and temperature, C -

concentration of the substance absorbing the light, gram-molecule/liter.

Optical density of solution is calculated by the formula:

.

(4)

What means that if the light-absorbing obeys to Bouger-Lambert-Behr

law, then optical density of solution is directly proportional to concentration of

substance in it. In that case the optical density D dependence on concentration C is

linear beginning form coordinate origin, as shown in the fig 2.

Fig. 2 Optical density dependence on concentration by Bouger-Lambert-Behr

law

Various substances absorb light waves with various wavelength differently.

If to draw a graph of dependence of substance’s optical density D on wavelength λ

of a light going through a substance, that graph will be a curve to have maximum

and minimum. The measuring of optical density should be carried out on such a

wavelength which corresponds to the maximum light absorbing in investigated

substance. Here is the highest sensitivity and fidelity of measuring achieved.

Needed wavelength is picked out by means of light filter which is selected so that

it passes through the light of that part of the spectrum where investigated substance

absorbs light maximally. In other words, minimum of the light filter absorbing is

to coincide with maximum absorbing of investigated substance, as it’s shown in

fig. 3.

Fig. 3 For measuring optical density of substance by means of light filter:

1 - light filter absorbing, 2 - substance absorbing.

Optical density if additive value, i.e. consists from optical densities of all the

components present in solution:

.

(5)

If for comparison to place in the cell solution containing all the components

in the same concentrations that investigated solution has but without component

which is to be found then optical density of that component will be defined. That’s

why solution placed in cell for comparison is called zero-solution. In case of two

component system the zero-solution is a solvent, for example water.

There’re couple of ways to analyze light absorbing. Quite simple and

convenient, especially for serial measuring, is method of calibration curve. The

essence of method consists in the following. First the optical densities of a number

(5-10) of solutions with known concentration (here’re mentioned solutions of

the substance concentration of which needs to be found) are measured. Then

calibration graph is built tracing on ordinate axis optical density, and on abscissa

axis - concentration, as in fig. 2.

When it’s done optical density of investigated solution will measured, and

its concentration will be found by the graph. If in some range of concentration

calibrated graph gets deflected from linear, i.e. the deviation from Bouger-

Lambert-Behr law, then measuring are carried out in concentration, where that law

is fulfilled.

The reasons why Bouger-Lambert-Behr law is not fulfilled can be various.

In some cases dependence D(C) deflects from the line when not monochromatic

D = ( A C A + ε B C B + ...)l

ε

light is used. Dissociation, polymerization of colored components, their interaction

with solvent or other components of solution also influence on light absorbing.

Frequently solution’s color and optical density depend on pH-value. Optical

density changes can occur in consequence of coagulation, in some cases because

of component destruction under the light influence etc. That’s why only newly

prepared solutions are used or they are added by stabilizers. If measuring

is distorted by outside colored substances, measuring is carried out on such

wavelength in which those substances don’t absorb light, or they are masked.

For determining concentration of harmful substances in solutions

concentration photoelectric colorimeter «КФК-2» can be applied.

It’s implemented to measure, in separate parts of wavelength diapason

315 .. 970 nanometer which is picked out by light filters, light-transmission

factor and optical density of liquid solution and solid bodies, and also determining

concentration of substances in solutions by drawing calibration graphs.

Colorimeter «КФК-2» allows to measure light transmission factors of

suspension dispersion, emulsion and colloidal solution in light passing through.

It’s applied at water-supply factories, in metallurgy, chemical, food industry,

agriculture, medicine etc.

Electrical scheme consist from light-electrical signal converters

(photodetector), measuring amplifier of direct current, voltage stabilizer 63 V

(supplying illuminating lamp) and 62 V (supplying photoelectric cell), and also

power supply ±18 V (supplying measuring amplifier of direct current).

Photodetectors and direct current amplifiers with all control and connecting

components are set in optical block, and voltage stabilizers with supplying

transformer - in power unit.

Optical block contains: illuminant; frame with optical instruments; light-

filters; cell holder; photometric device with direct current amplifier and control

buttons; indicator.

The general view of colorimeter is shown in fig. 4.

Fig. 4 Colorimeter «КФК-2»:

1 - microammeter; 2 - illuminant; 3 - light-filters switch; 4 - cell switch in

luminous flux; 5 - sensitivity switch (amplification factor).

Light-filter is moved into the luminous flux by knob 3.

Cells are switched in luminous flux turning knob 4 against stop, and

photodetectors - knob 5.

Microammeter 1 graduated in light-transmission factor T and optical density

D scale is as the indicator implement.

Switching light-filters knob 5 «Чувствительность» should be turned into

minimum position (minimum sensitivity). That prevents indicator from overload

and breakage.

Measuring with light-filters 315, 364, 400, 440, 490, 540 nanometer,

marked on bezel in black color, knob «Чувствительность» is set into one of the

positions «1», «2», «3» marked on bezel the same color.

Measuring with light-filters 590, 670, 750, 870, 980 nanometer,

marked on bezel in red color, knob «Чувствительность» is set into one of the

positions «1», «2», «3» marked on bezel the same color.

Do not touch with your fingers working section of cell surface (lower liquid

level in cell) placing cells into cell holder.

Contamination and solution drops on working section bring about obtaining

error data. Liquid should be poured into the cell up to the mark on the side wall

of cell. Sometimes liquid in the limited space of cell forms meniscus. It rises to a

significant height equal to 4 .. 6 mm through capillaries and especially through cell

edges. If a liquid level exceeds the mark on the side wall of cell, creeping over the

edges are observed, what makes an image of cell leakage.

Do not cline the cell with liquid placing it into cell holder.

After light-filter was switched or when the cell block was uncovered

for some time (over 5 minutes) measuring can be started passing 5 minutes of

photodetector light-striking.

Finishing

colorimeter

operation

before

power

is

off

knob «Чувствительность» should be placed in position 1, marked in red color,

and knob «Установка 100 грубо» - in ultimate left position, only when it’s done

turn the power off (switch «Сеть»).

Preparing to work includes steps listed below.

1. Take into volumetric flask (beginning from volumetric flask #1)

accordingly 2; 4; 6; 8; 10 ml of standard solution of colored component. Then add

distilled water into each flask (up to lower mark on flask neck) and mix water with

the component. That way each flask contains solution of colored component with

different concentration. Pour the researched solution into the volumetric flask.

2.

Turn on colorimeter for 15 minutes before starting measurement. During

warm up period the cell block should be opened (shutter over the photodetector

shields luminous flux).

3.

Pick appropriate to measuring color light-filter out (670 - red color).

4. Set minimum sensitivity of colorimeter. This is to turn the

knob «Чувствительность» into position «1» (red color), knob «Установка 100

грубо» - into ultimate left position.

5. Before every measuring and switching photodetectors check the

colorimeter indicates «0» in the scale of light-transmission T when the cell block

is opened. When indication is shifted from the «0» position it’s to be adjusted by

grooved potentiometer.

Measuring optical density:

1. place into luminous flux cell with a solvent (water), relative to which the

measuring is carried out;

2. cover the cell block;

3. set «0» in colorimeter scale by knobs «Чувствительность», «Установка

100 грубо» and «Точно». The knob «Чувствительность» can take any of

three positions «1», «2», «3»;

4. replace the cell with solvent or control solution by the cell with researched

solution turning the knob 4;

5. record indication of D scale for 5 standard and researched solutions;

6. carry on measuring for 3-5 times and take the mean value of all obtained

data as the result.

Steps to determine concentration of a substance are:

1. pick the light-filter out;

2. pick the cells out;

3. build the calibration graph for given substance;

4.measure the optical density of researched solution and determine

concentration of substance in given solution.

Calibration graph is drawn as following. Prepare the range of solutions with

known concentrations, covering range of possible concentrations of this substance

in researched solution.

Measure optical densities of all the solutions and build a calibration graph,

tracing on abscissa axis known concentrations and on ordinate axis - corresponding

to them optical densities.

Further built calibration graph is used to determine unknown concentration

of the substance in researched solution. For it pour the solution into the same cell,

calibration graph is built for, and switching the same light-filter determine optical

density of solution. After it find the concentration corresponding to measured value

of optical density in calibration graph.

Problem 1

Find concentration of X component in solution using following data:

optical density of X component in researched solution = 2.5; optical densities of

calibration solutions: D1= 4; D2 = 6; optical density of solvent = 2; concentrations

of X component in calibration solutions: C1= 10 mg/l; C2 = 35 mg/l.

Problem 2

Find optical density of X component in solution using following data:

concentration of X component in researched solution = 30 mg/l; optical

densities of calibration solutions: D1 = 3; D2 = 4; optical density of solvent = 1;

concentrations of X component in calibration solutions: C1 = 10 mg/l; C2 = 45 mg/

l.