Workplace exposure - Strategy for the evaluation of dermal exposure

This Technical Report gives guidance on approaches for awareness and evaluation of dermal exposure in workplaces.
This Technical Report describes strategies to evaluate exposure of the skin to chemical and biological agents qualitatively and quantitatively, e.g. to analyse exposure, as part of the risk assessment process, to investigate associations between exposure and diseases, and to evaluate control measures.
The definitions and procedures given in this document are primarily related to dermal exposure to chemical substances.
The specifications given in this Technical Report are not applicable to microbiological skin contaminants.

Exposition am Arbeitsplatz - Strategie zur Beurteilung der Hautbelastung

Exposition sur les lieux de travail - Stratégie pour l'évaluation de l'exposition dermique

Izpostavljenost na delovnem mestu – Strategija vrednotenja dermalne izpostavljenosti kože

General Information

Status
Published
Publication Date
14-Mar-2006
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
15-Mar-2006
Completion Date
15-Mar-2006

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SLOVENSKI STANDARD
SIST-TP CEN/TR 15278:2006
01-maj-2006
Izpostavljenost na delovnem mestu – Strategija vrednotenja dermalne
izpostavljenosti kože
Workplace exposure - Strategy for the evaluation of dermal exposure
Exposition am Arbeitsplatz - Strategie zur Beurteilung der Hautbelastung

Exposition sur les lieux de travail - Stratégie pour l'évaluation de l'exposition dermique

Ta slovenski standard je istoveten z: CEN/TR 15278:2006
ICS:
13.100 Varnost pri delu. Industrijska Occupational safety.
higiena Industrial hygiene
SIST-TP CEN/TR 15278:2006 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 15278:2006
TECHNICAL REPORT
CEN/TR 15278
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
March 2006
ICS 13.100
English Version
Workplace exposure - Strategy for the evaluation of dermal
exposure

Exposition sur les lieux de travail - Stratégie pour Exposition am Arbeitsplatz - Strategie zur Beurteilung der

l'évaluation de l'exposition dermique Hautbelastung

This Technical Report was approved by CEN on 20 September 2005. It has been drawn up by the Technical Committee CEN/TC 137.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,

Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,

Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15278:2006: E

worldwide for CEN national Members.
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Contents Page

Foreword..............................................................................................................................................................3

Introduction .........................................................................................................................................................4

1 Scope ......................................................................................................................................................5

2 Terms and definitions ...........................................................................................................................5

3 Assessment of dermal exposure .........................................................................................................7

4 Control ..................................................................................................................................................11

Annex A (informative) The conceptual model ..............................................................................................12

Annex B (informative) Estimation and Assessment of Substance Exposure (EASE)..............................14

Annex C (informative) DeRmal Exposure Assessment Method (DREAM).................................................16

Annex D (informative) Determinants of dermal exposure...........................................................................18

Bibliography ......................................................................................................................................................20

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Foreword

This Technical Report (CEN/TR 15278:2006) has been prepared by Technical Committee CEN/TC 137

“Assessment of workplace exposure to chemical and biological agents”, the secretariat of which is held by DIN.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN shall not be held responsible for identifying any or all such patent rights.

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Introduction

Dermal exposure assessment explores the dynamic interaction between environmental contaminants and the

skin. In contrast to inhalation exposure assessment, the assessment of dermal exposure remained a nascent

field of scientific research and applied occupational hygiene for most of the twentieth century, although

multiple fatalities and occupational skin diseases due to dermal exposure have been described in literature.

During the last decade, dermal exposure has received more attention, and one of the important results was

the development of a conceptual model for dermal exposure (see [1]). The model systematically describes the

transport of contaminant mass from exposure sources to the surface of the skin. The model provides a

structure for evaluating dermal exposure both qualitatively and quantitatively.

The purpose of evaluating dermal exposure can differ substantially, as exposure analysis (to give guidance to

control), risk assessment, and evaluation of exposure control can all be objectives to undertake assessments.

In order to give guidance and to harmonise basic concepts and actions a strategy for evaluation of dermal

exposure is proposed.
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1 Scope

This Technical Report gives guidance on approaches for awareness and evaluation of dermal exposure in

workplaces.

This Technical Report describes strategies to evaluate exposure of the skin to chemical and biological agents

qualitatively and quantitatively, e.g. to analyse exposure, as part of the risk assessment process, to

investigate associations between exposure and diseases, and to evaluate control measures.

The definitions and procedures given in this document are primarily related to dermal exposure to chemical

substances.

The specifications given in this Technical Report are not applicable to microbiological skin contaminants.

2 Terms and definitions

For the purposes of this Technical Report, the following terms and definitions apply.

NOTE The definitions are based on the implementation of exposure terminology by IPCS (see [2]) and the

conceptual model (see [1]), see also Annex A.
2.1
agent

any chemical or biological entity on its own or admixed as it occurs in the natural state or as produced by any

work activity, whether or not produced intentionally and whether or not placed on the market

NOTE Adapted from EN 1540.
2.2
dermal contact volume
volume containing the mass of the agent that contacts the exposure surface
NOTE 1 The dermal contact volume is given in litres (l).

NOTE 2 The dermal contact volume is equivalent to the volume of the skin contaminant layer, and for practical reasons

it is defined by the mass in kilograms (kg) of all substances contained in this compartment.

2.3
dermal exposure

process of contact between an agent and human skin at an exposure surface over an exposure period

2.4
dermal exposure concentration

exposure mass divided by the dermal contact volume or the exposure mass divided by the mass contained in

the skin contaminant layer

NOTE The dermal exposure concentration is expressed in grams per liter (g/l) or grams per kilogram (g/kg)

respectively.
2.5
dermal exposure loading
exposure mass divided by the exposure surface

NOTE For practical reasons it can be expressed as the time-averaged mass divided by area-averaged skin

contaminant layer surface area in grams per square centimetre (g/cm ).
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2.6
dermal exposure mass
mass of agent present in the dermal contact volume

NOTE 1 For practical reasons it is defined by the amount of agent in grams (g) present in the skin contaminant layer.

NOTE 2 The outcome of the process of dermal exposure, i.e. the contact, can be expressed by different parameters of

exposure.
2.7
dermal exposure surface
skin surface area where an agent is present

NOTE For practical reasons this is represented by a two dimensional representation of the skin contaminant layer in

square centimetres (cm ).
2.8
exposure period
time the agent is present in the skin contaminant layer, i.e. contact time

NOTE 1 The process by which an agent crosses an outer exposure surface of a target is called intake. In case of the

concentration driven transport from the skin contaminant layer into the skin, i.e. crossing the (exposure surface) interface

between skin contaminant layer and the stratum corneum as an absorption barrier, the process is called uptake. Therefore,

relevant for uptake would be the time- exposure concentration profile for an identified area of the skin contaminant layer

over a defined period of time.

NOTE 2 Other relevant types of time intervals, e.g. sampling time (B-C), immission or loading time (A-D), and post

emission time (D-E), are illustrated in Figure 1.
Key
X time
Y exposure loading
A-E exposure/contact time
A-D immission/loading time
D-E post immission time
B-C sampling time
Figure 1 — Different types of time intervals relevant in view of dermal exposure
2.9
immission

transport of an agent from a defined source to the skin or outer clothing contaminant layer compartment

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2.10
potential dermal exposure mass

mass retrieved from (outer and inner clothing contaminant layer and exposure mass, i.e. mass retrieved from

the covered and uncovered by clothing) parts of the skin contaminant layer compartment

NOTE For practical reasons related to sampling methodology and strategy the term potential exposure mass has

been introduced. It refers to the agent mass that has the potential the reach the skin (contaminant layer) since it has

landed on the clothing and the agent mass that has actually reached the skin. The conceptual model distinguishes

between outer and inner clothing contaminant layer compartment, respectively, and characterises the clothing itself as a

buffer layer.
2.11
skin contaminant layer compartment
compartment on top of the stratum corneum of the human skin

NOTE The skin contaminant layer compartment is formed by sebum lipids, sweat and additional water from

transepidermal water loss, rest products from cornification and unshed corneocytes, and is given by its three dimensional

volume.
2.12
workplace
the defined area or areas in which the work activities are carried out
[EN 1540:1998, 3.36]
3 Assessment of dermal exposure
3.1 General

Sampling strategies provide general guidelines to approach dermal exposure issues systematically. This

approach is according to the conceptual model illustrated in Figure A.1. The conceptual model structures the

process of dermal exposure to chemicals and assists in evaluating the performance of sampling methods.

Basically, the model systematically describes the transport of contaminant mass from the source onto the

surface of the skin. Six compartments, i.e. three environmental compartments (air, surface and source) and

three personal compartments (outer and inner clothing, and skin contaminant layer) and eight mass transport

processes onwards and from the compartments are distinguished and their mutual relationship is outlined.

3.2 Objectives
In general, five objectives for assessing dermal exposure can be distinguished:
a) evaluation of exposure processes and pathways

Evaluation of exposure processes and pathways is an important tool for selecting an adequate sampling

strategy and for effective risk management.
b) evaluation of exposure control measures or interventions

Evaluation of control measures is relevant in view of effectiveness of exposure reduction and post-intervention

surveillance.
c) risk assessment

Results for risk assessment purposes should be linked to results of hazard assessment. Hazardous agents

that show local effects are distinguished from hazardous agents that show systemic health effects after uptake

(see [3]). For the first group of agents, quantitative exposure assessment seems to be very difficult, however

some data are available on effect and dosage and duration.
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d) epidemiological investigations

To investigate possible associations between exposure and health effects by epidemiological investigations

estimates of relevant parameters of exposure are needed.
e) compliance

Compliance sampling is relevant in case exposure limits have been set. At the present time no such limits

have been set by National Authorities or other International Bodies. However, in-company exposure limits are

used as action levels or references for compliance. Such limits may be at the level of any parameter of dermal

exposure, i.e. exposure mass, exposure loading, exposure surface area, or at the level of determinants of

exposure, e.g. surface contamination in case of transfer, or at the level of intake by aggregated exposure

routes including the dermal route, e.g. biological monitoring limit values. The last two types of limit values,

however, are beyond the scope of this document.
3.3 Models and semi quantitative estimates
3.3.1 Objectives

Most models provide estimates of the likelihood of skin exposure or skin contamination that can be used as a

first tier in exposure assessment processes. Application of the models is analogous to the first two steps, i.e.

initial appraisal and basic survey, of a tiered approach as given for airborne contamination by EN 689. The

estimates provided by the models can be used for an initial evaluation of the exposure process, initial

exposure assessment in view of risk assessment processes, and estimation of exposure levels for

epidemiological studies. Moreover, the results will be helpful to select an appropriate sampling strategy for

quantitative exposure assessment and to prioritise control measures.
3.3.2 Methods

Categorical estimates, e.g. ever-never, yes-no or exposure classes (low, medium, high) can result from

human expert approaches. More structured approaches in combination with computer or human expert

systems can provide semi-quantitative estimates of dermal contamination. Basically, structured approaches

use identified or assumed determinants of exposure (or contamination). Examples of such approaches are

EASE (Estimation and Assessment of Substance Exposure, see [4]) and the semi-quantitative DREAM

(DeRmal Exposure Assessment Method, see [5]).

The decision logic of EASE is outlined in Annex B. According to EASE three key selections are made:

a) compound-specification physical state;
b) pattern-of-use one (range from non to wide dispersive use;
c) selection of level of contact.

The end-points of the decision logic (five boxes) are linked to ranges of exposure levels (see [6]).

DREAM consists of an inventory and an evaluation part. The inventory part comprises a hierarchically

structured questionnaire with six modules: company, department, agent, job, task and exposure (see Table

C.1). Information is obtained by observations and interviews. The modules address general information as

well as possible determinants of exposure as identified by the conceptual model and by evaluating literature.

In the DREAM model evaluation of exposure takes place on the level of tasks. A summary of the evaluation

module is given in Figure C.1. Examples of determinants of dermal exposure are identified (see [7]) and given

in Annex D.

For an initial systematically description of dermal exposure situations in different industry sectors, so called

dermal operation (DEO)-units can be used, as developed by the RISKOFDERM project (see [8]). The DEO-

units handling of contaminated objects, manual dispersion, hand tool dispersion, spray dispersion, immersion,

and mechanical treatment include several task-groups or scenarios.
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In the RISKOFDERM project a so-called toolkit for dermal exposure assessment and management has been

developed (see [9]). The toolkit provides some first estimates to determine the risk associated to dermal

exposure to hazardous substances. Default values for potential exposure loading per unit time for hands and

body for the DEO-units were derived from literature (see [10]). In addition, the magnitude of the effect of

determinants or modifiers of exposure was estimated (see [11]).

Semi-deterministic models or mixed subjective (semi-) deterministic models have been developed for specific

exposure scenario’s, e.g. paint spraying (see [12] and [13]), and non-industrial pesticide application, and re-

entry work (see [14]), and biocides (see [15]).
3.4 Measurements to quantify dermal exposure
3.4.1 Objectives and sampling strategy

For the objectives for assessing dermal exposure (see 3.2), the following should be taken into consideration:

a) for evaluating exposure processes and pathways and in view of the conceptual model it is relevant to

know mass transport rates from different compartments to the skin contaminant layer and how the

different transports contribute to total contamination;

b) to evaluate exposure control measures it would be appropriate to measure compartment agent

(contaminant) mass;

c) for risk assessment it would be relevant to measure the concentration/time profile in the skin contaminant

layer;

d) for compliance measurements the definition of the exposure limit would prescribe what should be

measured;

e) for epidemiological investigations the mechanisms of the health effect or other considerations will

determine the relevant parameters of exposure.

Developing an appropriate sampling strategy related to the sampling objectives should include the selection of

the relevant:
 agent;
 workplace;
 population/ jobs/ tasks;
 sample size;
 time of sampling;
 sampling duration;
 frequency of sampling;
 body locations;
 sampling method(s).
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3.4.2 Measurement principles

Selection of the measurement principle depends very much on the sampling objective and is a key issue in

designing a measurement strategy. Measurement methods for dermal exposure assessment, i.e. taking a

substance and identify and quantify an agent, can be grouped into three major principles:

 sampling: interception of agent mass transport by the use of collection media placed at the skin surface or

replacing work clothing during the sampling time, i.e. interception techniques. Detection e.g. chemical

analysis of extracts from the collection matrix;

 sampling: removal of the agent mass from the skin contaminant layer at any given time or the end of the

sampling period, i.e. removal techniques. Detection e.g. chemical analysis of extracts from the removal

matrix such as wash liquid, wipe fabrics;

 direct assessment: In situ detection of the agent or a tracer at the skin surface, e.g. by image acquisition

and processing systems, at a given time.
The different sampling and measurement principles estimate different quantities:
 interception techniques estimate exposure mass;
 removal and in situ (direct) techniques estimate exposure loading;
Furthermore the results obtained by different sampling principles
...

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