H 2 O H 2 O + e - H + H 2 O 2 OH o HO 2 OH - H o H 2 WATER ...

kissimmeemisologistΒιοτεχνολογία

14 Δεκ 2012 (πριν από 4 χρόνια και 6 μήνες)

110 εμφανίσεις

By Dr. Kunal Shinde

Radon

X
-
Rays

Consumer

Products

Nuclear

Power

Radioactive

Waste

Nuclear

Medicine

Solar Radiation

Cosmic Rays

Terrestrial

Radiation

Food &

Drink

Each

Other






Radiation in Life


Non
-
ionizing



Ultraviolet, visible, infrared, microwaves,
radio & TV, power transmission


Ionizing



Radiation capable for producing ions when
interacting with matter


x
-
rays, alpha, beta,
gamma, cosmic rays

10

-
14

10

-
12

10

-
10

10

-
8

10

-
6

10

-
4

10

-
2

1

10

2

10

4

10

6

10

8

Wavelength in Meters

10

10

10

8

10

6

10

4

10

2

1

10

-
2

10

-
4

10

-
6

10

-
8

10

-
10

10

-
12

10

-
14

Broadcast

Short wave

TV

FM

Radar

Infrared

Near

Far

Visible

Ultraviolet

X Rays

Gamma Rays

Cosmic Rays

Power

Transmission

Ionizing Radiation

Nonionizing Radiation

Energy
-

Electron Volts

High

Low



Natural





Man

--

made



Sources


Ultraviolet light


Visible light


Infrared radiation


Microwaves


Radio & TV


Power transmission


Ultraviolet


Black light


induce
fluorescence in some materials


Vision


very small portion that animals
use to process visual information


Heat


infrared


a little beyond the red
spectrum


Radio waves


beyond infrared


Micro waves


Electrical power transmission


60 cycles
per second with a wave length of 1 to 2
million meters.


Sun light


Most harmful UV is absorbed by the
atmosphere


depends on altitude


Fluorescent lamps


Electric arc welding


Can damage the eye (cornea)


Germicidal lamps


Eye damage from sun light


Skin cancer


High ultraviolet


kills bacterial and other
infectious agents


High dose causes
-

sun burn


increased risk
of skin cancer


Pigmentation that results in suntan


Suntan lotions contain chemicals that absorb
UV radiation


Reaction in the skin to produce Vitamin D that
prevents rickets


Strongly absorbed by air


thus the danger of
hole in the atmosphere


Energy between 400 and 750 nm


High energy


bright light produces of
number of adaptive responses


Standards are set for the intensity of light
in the work place (measured in candles or
lumens)


Energy between 750 nm to 0.3 cm


The energy of heat


Heat is the transfer of
energy


Can damage


cornea, iris, retina and lens
of the eye (glass workers


“glass blower’s
cataract”)



Energy between 0.1 cm to 1 kilometer


Varity of industrial and home uses for
heating and information transfer (radio, TV,
mobile phones)


Produced by molecular vibration in solid
bodies or crystals


Health effects


heating, cataracts


Long
-
term effects being studied




Standard in homes and businesses


Highest level of exposure from electric
-
power generation and distribution system
(high voltage power lines)


Medical system


Magnetic imaging


Acute health effects


shock


Long
-
term health effects appear to be few
but may some data do suggest adverse
effects


Ionization Defined



Radiation capable for producing ions when
interacting with matter


in other words
enough energy to remove an electron from
an atom.



X
-
rays,


Radioactive

material

produce



Alpha,


Beta,


Gamma

radiation,


Cosmic

rays

from

the

sun

and

space
.




The

primary

radioactive

elements

in

the

Earth's

crust

are

uranium,

thorium,

potassium,

radium



These

radioactive

elements

can

be

categorized

into

three

general

groups


Primordial


Cosmic

radiation


Human

Produced





typical

exposures

to

radiation

can

come

from

the

following

sources
:


Cosmic

rays,

28

millirem



Rocks

and

soil,

28

millirem



Medical

x
-
rays,

39

millirem



Nuclear

medicine,

14

millirem



Radon,

200

millirem



Radium

wrist

watch,

3

millirem



Cigarettes

(
1

1
/
2

packs

day,

to

lung),

8
,
000

millirem



Building

materials,

masonry,

7

millirem



Uranium

glaze

in

dinnerware,

to

skin,

2
,
400

millirem





about

11
%

of

a

person’s

total

exposure

to

radiation

comes

from

the

person’s

body




Potassium

and

carbon

are

two

of

the

main

sources

of

internal

radiation

exposures

and

they

enter

our

bodies

through

the

food

we

eat

and

the

air

we

breathe
.




Radon


Medical

X
-
rays


Internal


Terrestrial


Cosmic


Nuclear

Medicine


Others



Useful

effects






Harmful

effects





Industrial

uses


Energy



Research


Medical

uses



Diagnostic

purposes


Scientific

research


Therapy



Genetic

Engineering



Environmental

studies




X
-
rays



Computed

Tomography





Radiotherapy




Nuclear

medicine



Fall

under

2

broad

categories



Somatic



harmful

to

person

being

irradicated



Genetic



harmful

to

future

generations



Teratogenic



Effects

to

the

unborn

fetus

irradiated

in
-
utero

Data

are

not

available

to

indicate

if

there

is

a

threshold

below

which

no

harmful

effect

will

occur

therefore

A

recommendation

that

5

R

per

year

is

the

max

permissible

dose

really

means





That

in

light

of

present

knowledge,

this

dose

is

not

expected

to

cause

appreciable

bodily

injury

to

a

person

at

any

time

during

his

lifetime”



General

radiation

doses

to

the

entire

body

and

expected

effects
:


0
-
5

rem

received

in

a

short

period

or

over

a

long

period

is

safe

we

don’t

expect

observable

health

effects
.


5
-
10

rem

received

in

a

short

time

or

over

a

long

period

is

safe

we

don’t

expect

observable

health

effects
.

At

this

level,

an

effect

is

either

nonexistent

or

too

small

to

observe
.


10
-
50

rem

received

in

a

short

time

or

over

a

long

period

we

don’t

expect

observable

health

effects,

although

above

10

rem

the

chances

of

getting

cancer

are

slightly

increased
.

We

may

also

see

short
-
term

blood

cell

decreases

for

doses

of

about

50

rem

received

in

a

matter

of

minutes
.


50
-
100

rem

received

in

a

short

time

will

likely

cause

some

observable

health

effects

and

received

over

a

long

period

will

increase

the

chances

of

getting

cancer
.

Above

50

rem

we

may

see

some

changes

in

blood

cells,

but

the

blood

system

quickly

recovers
.




100
-
200

rem

received

in

a

short

time

will

cause

nausea

and

fatigue
.



100
-
200

rem

received

over

a

long

period

will

increase

a

person’s

chances

of

getting

cancer
.



200
-
300

rem

received

in

a

short

time

will

cause

nausea

and

vomiting

within

24
-
48

hours
.

Medical

attention

should

be

sought
.


300
-
500

rem

received

in

a

short

time

will

cause

nausea,

vomiting,

and

diarrhea

within

hours
.

Loss

of

hair

and

appetite

occurs

within

a

week
.

Medical

attention

must

be

sought

for

survival
;

half

of

the

people

exposed

to

radiation

at

this

high

level

will

die

if

they

receive

no

medical

attention
.


500
-
1
,
200

rem

in

a

short

time

will

likely

lead

to

death

within

a

few

days
.


Greater

than

10
,
000

rem

in

a

short

time

will

lead

to

death

within

a

few

hours
.



Effective dose

Radiation source



0.01
rem

Annual dose living at nuclear
power plant perimeter,

full mouth
dental
x

rays, skull or chest
x

ray

≤ 0.1
牥r

卩p杬攠獰s湥Ⱐ慢摯浥m 潲⁰敬癩挠
☠桩&
x

牡r猬s浡浭m杲gm

≤ 0.5
牥r

䉡物r洠獴畤楥猬

桥慤 捴c 獰s湥
x

牡r 獥物敳Ⱐ浯獴e湵捬c慲a
浥m楣i湥 獣慮猬s慮湵慬 湡瑵牡氠
扡捫杲c畮搠牡r楡瑩潮 摯獥

≤ 1.0
牥r

䉡物r洠獴畤楥猬s灥汶l挠捴

≤ 5.0
牥r

䍡牤r慣a
捡瑨整e物獡瑩潮
Ⱐ捯牯湡特

慮杩o
.

harmful

to

person

being

irradicated

Cellular Organization



Absorption of Radiation


Ionization


Chemical Change


Repair or Damage

High Dose Effects

Cell

death

Tissue or organ effects

Whole body effects

Low Dose Effects

Mutations

Cancer

Effects to unborn

H
2
O

H
2
O
+

e
-

H
+

H
2
O
2

OH
o

HO
2

OH
-

H
o

H
2

WATER


Radiation Induced Decomposition
of Water Within a Cell

Incoming

Radiation

Production of free radicals within the cell can result in indirect effects

Most abundant molecule within humans: Water


Potential Outcomes of Radiation

Damage to Parent Cells


Actively

dividing

cells

are

most

sensitive

to

radiation

damage
.


Tissues

that

are

more

sensitive

include

skin,

hair,

early

blood

cells,

and

lining

of

the

intestine
.


Tissues

that

are

less

sensitive

include

muscle,

bone,

brain,

and

connective

tissue
.


Relative Sensitivity of

Cell and Tissue Types


Lymphocytes





Spermatogonia


Hematopoietic (Blood Forming)


Intestinal Epithelium


Skin


Nerve Cells


Muscle Tissue


Bone


Collagen





Biological Effects from


Low Doses of Radiation

Biological effects from low doses potentially occur
due to chronic exposures. A
chronic exposure

occurs when a relatively small amount of radiation is
absorbed by tissue over a long period of time.



Under 5 rad of exposure
-

No detectable health
effects in exposed individual


Chronic exposures result in an increased risk
in latent adverse health effects


Health effects could be genetic effects or
somatic effects



Skin

lesions


Cancer

(leukemia,

tumors)


Cataracts


Sterility


Epilation

(hair

loss)


Hematological

effects



skin

erythema



thinning

of

skin



blistering



poorly

healing

ulcer



malignancy



WBC

count

drops

in

2
days



Platelets

by

6

days



RBC

count

drops

by

110

days



A

single

radiation

of

250

rad

produces

non
-
progressing

cataract,

whereas

500

rad

produce

progressive

cataract



it

is

a

STOCHASTIC

effect



STOCHASTIC

effect



defined

as

an

effect

in

which

the

probability

of

occurrence

increases

with

increased

dose
.

But

the

severity

does

not

depend

on

magnitude

of

the

absorbed

dose



NON
-
STOCHASTIC

effect



defined

as

a

somatic

effect

which

increases

in

severity

with

increasing

magnitude

of

absorbed

dose



Occurs

in

industrial

accident

with

high

level

radioactive

material,

in

nuclear

plant,

explosion

of

nuclear

weapons



Sub
-
clinical

syndrome




Hematopoietic

syndrome




G
.
I
.

syndrome




Neurovascular

syndrome




Below

25

rad



no

change

in

blood

count,

but

chromosomal

aberrations



25
-
50

rad



WBC

temporary

fall



50
-
200

rad



nausea,

vomiting,

moderate

recoverable

WBC

count

fall




Exposure

200
-

800

rad



Prodromal



2

hours

to

2

days


nausea,

malaise



Latent



2

days

to

3

wks


bone

marrow

&

lymph

shows

loss

of

cells



Manifest



full

blown

syndrome

fever,

malaise,

diarrhoea
,

petechiae
,

pancytopenia



Recovery





lower

dose

200
-
300

rad

5
wks

to

6

months



incomplete

recovery,

more

than

500

rad

fatal

outcome

due

to

severe

leucopoenia,

infection

&

haemorrhage







Exposure

800
-
5000

rad



Prodromal



within

2

hrs

nausea,

vomiting




Latent



may

not

be

present


last

2
-
5

days



Manifest



1
-
2

wks

--

fever,

increasing

diarrhoea

due

to

denudation

of

small

bowel

lining

epithelium,

dehydration

due

to

associated

no

fluid

reabsorption
,

sepsis,

depletion

of

WBC,

shock,

death




Exposure

5000

rad




Symptoms

start

in

few

min


nausea,

vomiting,

rapid

dehydration,

drowsiness,

ataxia,

convulsion

due

to

cerebral

edema,

vasculitis

&

injury

to

nerves



Death

occurs

within

few

days




Bone

marrow

&

G
.
I

syndrome

may

be

associated



Pre
-
implantation

stage

(
0

to

10

days)



small

dose

of

5
-
15

rad

can

kill

the

embryo,

but

surviving

embryo

are

normal

except

chromosomal

damage



Organogenesis

stage

(
11

to

41

days)



every

embryo

surviving

radiation

develops

an

anomaly

especially

in

organs

undergoing

most

active

multiplication

(mitosis)

&

differentiation

(maturation)





From

17
th

day

till

delivery



neuroblasts
,

which

are

very

radiosensitive,

are

present

throughout

the

CNS

&

a

small

dose

of

25

rad

can

be

lethal

this

is

reason

for

such

large

CNS

anomalies



Less

than

2
-
3

wks



lethal

effect

with

absorption,

low

anomalies



4
-
11

wks



severe

anomalies

of

many

organs



11
-
16

wks



microcephaly
,

stunted

growth

,

genital

organ

anomalies



16
-
20

wks



mild

microcephaly
,

stunted

growth,

mental

retardation




More

than

30

wks



rare

visible

abnormalities





harmful

to

future

generations


Genetic

mutations

occur

from

incorrect

repair

of

damaged

chromosomes

in

egg

or

sperm

cells
.


Ovaries

can

repair

mild

radiation

damage
.


Genetic

mutations

may

show

up

in

future

generations
.


Radiation
-
caused

genetic

mutations

have

been

shown

in

animal

studies

at

very

high

radiation

doses

(>
25

rem
)
.


Radiation
-
caused

genetic

mutations

have

not

been

seen

in

exposed

human

populations
.


Potential Radiation Damage to DNA

Most critical molecule within humans: DNA


Direct

effect

on

molecule

by

ionization

or

excitation

of

the

molecule

and

subsequent

dissociation

of

the

molecule



Indirect

damage


Water

molecule

is

ionized,

breaks

apart,

and

forms

OH

free

radical
.


OH

free

radical

contains

an

unpaired

electron

in

the

outer

shell

and

is

highly

reactive
:

Reacts

with

DNA
.


75

percent

of

radiation
-
caused

DNA

damage

is

due

to

OH

free

radical
.



Direct

damage


DNA

molecule

is

struck

by

radiation,

ionized,

resulting

in

damage
.

Chromosome Damage

Formation of a ring and fragments followed
by replication of chromosomes.

Chromosome Damage

Interchange between two chromosomes
forms a chromosome with two centromeres
and fragment, followed by replication.


The

cell

might
:


Repair

mild

damage
.



Have

some

mild

damage

that

sits

inactive

until

another

agent

interacts

with

the

same

cell
.



(If

it

is

a

reproductive

cell

like

sperm

or

egg

cells)

have

damage

to

the

genetic

code

that

doesn’t

show

up

until

future

generations

(your

children,

their

children,

etc
.
)
.



Have

some

damage,

causing

it

to

become

a

cancer
.



Stop

functioning
.



Be

killed
.



All

radiation

may

not

be

harmful


However,

data

does

not

contradict

the

linear,

non
-
threshold

theory

for

some

effects

(cancer,

genetic

effects)


Effects

from

high

doses

are

known

fairly

well


Depending

upon

dose,

radiation

may

affect

various

cells,

tissues,

and

organs


Without

medical

treatment,

about

50
%

of

people

exposed

to

approximately

450

rad

of

radiation

are

expected

to

die

within

1
-
2

months


Acute

(short
-
term)

effects

below

100

rad

are

relatively

minor


Genetic

effects

have

not

been

detected

in

people


Genetic

effects

may

occur,

but

at

rates

so

low

that

they

have

not

been

detected

over

the

rate

that

occurs

in

the

absence

of

radiation


The

unborn

child

and

young

children

appear

to

be

more

sensitive

to

the

effects

of

radiation

than

adults

are


The

rate

that

effects

occur

is

very

low