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EXPOSURE ASSESSMENT

 

Dr Norlen Mohamed

M.D, M.COMM.MED (ENV.

HEALTH)

Environmental Health Unit

Disease Control Division

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DEFINITIONS

• Exposure – The contact with a cheica!" #io!o$ica!" or ph%sica!

a$ent at the #oun&ar% o' the #o&% o(er a speci'ie&tie)

• Exposure assessent – Is the &eterination or estiation o' the route"

a$nitu&e" 're*uenc%" &uration" an& characteristics o'the expose& popu!ation)

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DEFINITIONS +cont),

• Exposure Pathwa% – -ow a su#stance o(es 'ro the source to the receptor +in this

case" peop!e,)

• Exposure Route

 – -ow a su#stance contacts the #o&% an& resu!ts in an interna!&ose +inha!ation" in$estion" &era! penetration,)

• Dose – Internal Dose. the aount o' a su#stance crossin$ one o' the

route #arriers into the #o&% – Biologically-effective dose. the aount o' a su#stance reachin$

a tar$et or$an)

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Exposure E!eents

containantsource

 transport an&

trans'oration

 exposure point

e&ia

 exposure

route

 receptor

concentration in Air" water" soi!"

'oo&

 Inha!ation

In$estion

Dera!

Inta/e

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Exposure Assessent

 Assessent o#0ecti(es

• To &eterine the route o' exposure

 – Inha!ation" in$estion" &era! route• To esta#!ish the a$nitu&e o' exposure

• To estiate the 're*uenc% o' exposure

• To i&enti'% the characteristics o' expose&popu!ation

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Exposure Assessent

 Assessent o#0ecti(es

• To &eterine the route o' exposure

 – To consi&er tota! inta/e 'ro a!! en(ironenta!e&ia +air" 'oo&" water" soi!,

 – To consi&er tota! inta/e throu$h a!! route o'

exposure +Inha!ation" in$estion" &era!,

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From:

Paustenbach, DJ.

(2000) The practice of

exposure assessment:

a state-of-the-artrevie. J Toxicol Env

 Health, !:"#$-2$"

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%ifetime cancer ris& ' F  x CDI  *  +fD or +f '

here to /et this here to /et this

o to /et this

1P34+1

51617T

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Toxicit% Data

Exposure Data

 Data Input

Ris/ Estiation

 

1ontainants

!e(e!s in

En() e&ia

  1onsuptionData

  pop)atRis/

 -a2ar&3t%pe o' toxicit%

 &ose3response3R'D" NOAE4

31SF

Estimating Intake

For &i''erent route o'exposure

 Inha!ation  In$estion  Dera!

 In'oration nee&e& 'or -RA

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Exposure Data

 

1ontainants

!e(e!s in

En() e&ia

  1onsuptionData

  Pop)atRis/

Monitorin$ &ata

3F51

3Drin/in$ 6ater 

3Air

3ri(ers

Sur(e%

Mo&e!in$

Nationa! &ietar%

1onsuption

Data

Site speci'ic

Sur(e% &ata

 6ho7

6here7

 DATA INPUT

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Estimating IntakeFor &i''erent route o'

exposure

 Inha!ation  In$estion  Dera!

Inha!ation o' air#orne particu!ates

Inta/e +$8/$3&a%, 9 1AP x IR x ET x EF x ED

  +:6 x AT,

1AP 9 cheica! conc in air +$8;,IR 9 Inha!ation Rate +;8&a%,

ET 9 Exposure tie +hours 8

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Estiatin$ Inta/eFor &i''erent route o'

exposure

 Inha!ation  In$estion  Dera!

In$estion o' containate& 'oo& +e$. (e$eta#!es,

Inta/e +$8/$3&a%, 9 1AP x IR x FI x EF x ED

  +:6 x AT,

1AP 9 cheica! concentration in 'oo& +$8/$,IR 9 In$estion Rate +/$8ea!,

FI 9 Fraction In$este& 'ro containate& area +> to ?,

EF 9 Exposure Fre*uenc% +&a%s8%ear,

ED 9 Exposure Duration +%ears,

:6 9 :o&% 6ei$ht +/$,

 AT 9 A(era$in$ Tie +perio& o(er which exposure a(era$e& in &a%s,

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Estiatin$ Inta/eFor &i''erent route o'

exposure

 Inha!ation  In$estion  Dera!

In$estion o' containate& 'oo& +e$. (e$eta#!es,

Inta/e +$8/$3&a%, 9 1AP x 1F x SA x AF X EF x ED

  +:6 x AT,

1AP 9 cheica! concentration in soi! +$8/$ soi!,

1F 9 1on(ersion Factor 

SA 9 S/in sur'ace area a(ai!a#!e 'or contact +c to ?

EF 9 Exposure Fre*uenc% +e(ent8%ear,

ED 9 Exposure Duration +%ears,

:6 9 :o&% 6ei$ht +/$,

 AT 9 A(era$in$ Tie +perio& o(er which exposure a(era$e& in &a%s,

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Exap!e //

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Exposure Assessent

 Assessent o#0ecti(es

• To i&enti'% the characteristics o' expose&popu!ation – Si2e

 – A$e $roup

 – Sex

 – Ethnicit% – 4ocation

 – -ea!th status

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SUMMAR@ OF EXPOSURE ASSESSMENT 

-a2ar& 1oncentration

In en() e&ia

routes 1DI 'oreachroute

Tota!1DI

 Air Foo& water Soi! inha!ation

in$estion

&era! 1DII

1DIO

1DID