Page 4 - Volume 2, Issue 1, January 2009

Glass and Machera

2

thorization of the product) which has the re-

sponsibility of carrying out risk assessments

for the examined PPPs which contain Annex

I listed active substances. With the informa-

tion from the hazard assessment for the ac-

tive substance(s), as concluded during the

Annex I inclusion, the regulatory authori-

ty for each individual MS decides wheth-

er the PPP can be used safely under nation-

al conditions. With decisions now made on

a European basis for the selection of active

substances for inclusion in the Annex I, it is

important that data and information used

in the initial risk assessment (such as expo-

sure models) are valid for all MS, and not just

for those that have generated the most in-

formation.

There are various tasks involved which

result in occupational exposure to pesti-

cides, but the greatest exposures are often

associated with the operator, during both

the handling of the concentrated pesticide

when mixing and loading, and the appli-

cation of the diluted pesticide in the field.

Studies to measure operator exposure have

been carried out since the 1960’s using a

range of methodologies to determine po-

tential dermal and inhalation exposure.

More recent studies have measured dermal

exposure and the absorbed dose, and data

is now available from a wide range of stud-

ies using different application techniques.

The estimation or measurement of operator

exposure is a key element of occupational

health and a requirement of the risk assess-

ment in pesticide registration (van Hemmen

and Brouwer, 1997), which is carried out ac-

cording to the directive 91/414/EEC.

Three predictive models are used for

regulatory purposes within the EU: the UK

model (Martin, 1990); the German model

(Lundehn

et al.

, 1992) and the Dutch mod-

el (van Hemmen, 1992). These models con-

tain experimental data obtained from par-

ticular use scenarios and were incorporated

into the European Predictive Operator Ex-

posure Model (EUROPOEM) Expert Group

under concerted Action AIR3-CT93-1370.

The EUROPOEM is a database for reference

rather than an actual tool for regulators, and

tends to be used in conjunction with exist-

ing models developed in the UK and Germa-

ny. Data have been added since EUROPOEM

was set up, with field assessments carried

out, especially in southern Europe (Machera

et al.

, 2001; Glass

et al.

, 2002) as part of the

project SMT4-CT96-2048. In North Ameri-

ca, a Pesticides Handlers Exposure Database

(PHED) provides generic mixer/loader/appli-

cator exposure data (Krieger, 1995). Work is

being done to combine PHED and EUROPO-

EM datasets in a new North American mod-

el, the Applicator and Handlers Exposure

Database (AHED).

The modelling of operator exposure still

relies on a number of assumptions related

to the personal protective equipment (PPE)

worn by operators, the protection factor of-

fered by coveralls for example. The degree

of dermal absorption of the compound is a

substantial information for reliable human

risk assessment. This information is usually

derived from

in vivo

animal data and

in vit-

ro

human and animal skin data. When there

are no available data for a substance, default

values of dermal absorption are used.

The methods used to measure operator

exposure, and the subsequent use of these

data together with toxicology data in risk as-

sessments are discussed.

Routes of operator exposure

The most important route for exposure

to pesticides is dermal for the majority of

application techniques. The other routes

are inhalation, particularly with fogging and

misting application techniques, and by acci-

dental ingestion (oral), for example by eat-

ing or smoking while working, or not wash-

ing adequately after work.

Potential dermal exposure is the total

amount of pesticide landing on the body,

including amounts landing on clothing. The

mass of pesticide available on the skin for

absorption into the body is the actual der-

mal exposure, which is the amount depos-

ited directly on the skin plus any that pene-

trates clothing.

Inhalation exposure, generally contrib-

utes much less to the absorbed dose than