Beoordelen van piekblootstelling aan oplosmiddelen...5 TNO KvL, CGC bijeenkomst 12 maart 2009 ... ratioratio 1.2 1.2 1.2 ––––2.422..442.4 >>>> ==== 18 TNO KvL, CGC bijeenkomst

Liesbeth Preller

Beoordelen van piekblootstelling

aan oplosmiddelen Maar welke maat hanteren?

TNO KvL, CGC bijeenkomst 12 maart 20092

Used definitions

• Exposure based• ’High’ exposure during day

• ‘High’ exposure during longer period of time

• Rapid increase in exposure

• Health based• Period during which health effects occur

• Challenge of allergenic effects

• Reactive Airways Dysfunction Syndrome


Relevance

• Prevention of health effects due to peaks in

exposure

• (Effective) reduction of 8hr-TWA/dose by

reduction of exposure peaks


Background

• Role VOC peaks in Chronic Toxic

Encephalopathy suspected

• With similar dose, does exposure pattern with

peaks more harm than constant exposure?

• Do we (therefore) need standardization of

peaks? If yes, how?


‘Evidence’

• Not based on epidemiological data

• Toxicological data: some indications related to solvents

• Subjective acute effects sometimes in relation to chronic effects

• TNO study Bos et al., 1998

• Physiological Based PharmacoKinetic modelling

• Distribution of ‘mother’ compound over body tissues

• Comparison of realistic exposure scenarios with and

without peaks: PER, TRI, Toluene, Styrene

• High doses: peaks lead to higher brain and blood

concentrations


Study

• Evaluate ways to describe exposure profiles in

terms of peak exposure

• Measurements during spraying of VOC

• 27 workers, 15 companies in various sectors

• Direct reading instrument (PID)

• Charcoal tubes







Definition of a peak

Exposure above reference level


Peak characteristics

0 10 20 30

Time (min)

Ex

po

su

rele

ve

l Maximum peak

Reference level

Average peak=[E(A) + E(B) + E(C) + E(D) + E(E)]/5

A

B

C

Duration

of peak

Time between peaks

Number of peaks per hour = 6

Ratio=mean maximum

peak / mean average peakD

E


Peak measures

• Variation in reference level:

• TWA exposure during sampling

• OEL mix during sampling

• Variation in averaging time:

• 5 seconds

• 1 minute

• 15 minute

• Total of 36 peak measures


Averaging times

0 50 100 150 200 250 300 350 400 450 500

Time (sec)

Concentration

VOC (ppm)


Results - basic information

AM (SD )AM (SD )AM (SD )AM (SD ) R angeR angeR angeR ange

D uration (m in)D uration (m in)D uration (m in)D uration (m in) 46.5 (29)46.5 (29)46.5 (29)46.5 (29) 4.6 4.6 4.6 4.6 ---- 159 159 159 159

TW A exposure (ppm )TW A exposure (ppm )TW A exposure (ppm )TW A exposure (ppm )

78.4 (73)78.4 (73)78.4 (73)78.4 (73) 6.8 6.8 6.8 6.8 ---- 341 341 341 341

O ELm ix (ppm )O ELm ix (ppm )O ELm ix (ppm )O ELm ix (ppm ) 78.9 (68)78.9 (68)78.9 (68)78.9 (68) 26 26 26 26 –––– 288 288 288 288


Influence of reference value and

averaging time

Param eterParam eterParam eterParam eter AMAMAMAM O EL O EL O EL O EL vs vs vs vs

TW ATW ATW ATW A

longer av. longer av. longer av. longer av.

tim etim etim etim e

# peaks/hr# peaks/hr# peaks/hr# peaks/hr 1 1 1 1 –––– 71 71 71 71 <<<< <<<<

duration (sec)duration (sec)duration (sec)duration (sec) 33 33 33 33 –––– 1601 1601 1601 1601 >>>> >>>>

tim e betw een (sec)tim e betw een (sec)tim e betw een (sec)tim e betw een (sec) 32 32 32 32 ---- 792 792 792 792 >>>> >>>>

m axim um (ppm )m axim um (ppm )m axim um (ppm )m axim um (ppm ) 106 106 106 106 –––– 161 161 161 161 ==== ====

average (ppm )average (ppm )average (ppm )average (ppm ) 96 96 96 96 ---- 111 111 111 111 ==== ====

ratioratioratioratio 1.2 1.2 1.2 1.2 ––––2.42.42.42.4 >>>> ====


Exposure profile per sector

(OELmix, 5 sec.)

0 200 400 600 800 1000 1200 1400

Time (sec)

To

tal V

OC

co

nce

ntr

ation

Wood assembly

Spray painting of

transportation means

Glass-reinforced

plastics industry


Data analysis

• Principal components analysis

• 24 peak measures (15 min. values excl.),

plus TWA exposure during spraying


Principal Components Analysis

Com ponentCom ponentCom ponentCom ponent EigenEigenEigenEigen----

valuevaluevaluevalue

% Explained % Explained % Explained % Explained

variancevariancevariancevariance

VariablesVariablesVariablesVariables

1111 12.512.512.512.5 50505050 TW ATW ATW ATW A

m axim umm axim umm axim umm axim um

average average average average

2222 4.64.64.64.6 19191919 tim e betw een peakstim e betw een peakstim e betw een peakstim e betw een peaks

3333 3.33.33.33.3 13131313 # peaks/hr# peaks/hr# peaks/hr# peaks/hr

durationdurationdurationduration


Concluding remarks

• Results are situation specific

• Strategy can be used for variable reduction in description of

exposure scenario

• Improvement of exposure-response studies

• Input for standard setting for specific exposure indices

• Little evolution with regard to peak exposure, e.g. REACH.

Documents

Beoordelen van piekblootstelling aan oplosmiddelen...5 TNO KvL, CGC bijeenkomst 12 maart 2009 ... ratioratio 1.2 1.2 1.2 ––––2.422..442.4 >>>> ==== 18 TNO KvL, CGC bijeenkomst