Page 6 - Volume 2, Issue 1, January 2009

Glass and Machera

4

and other confounding factors on rates of

metabolism. Urine samples, taken over a pe-

riod of at least 24 hours, tend to be used for

biomonitoring studies.

Examples of data for operator exposure

The hand held application technique

is generally considered to represent the

worst-case scenario for applicator exposure,

due to the proximity of the nozzle to the

operator. In the EU-funded project SMT4-

CT96-2048, data for hand held application

techniques were generated in a number of

southern European countries (see Figure 1).

These studies provided data for the devel-

oping EUROPOEM database, which till then

had few datasets for hand held applications,

and those available concerned outdoor ap-

plication in northern Europe.

In considering operator exposure to pes-

ticides, studies should be done to allow ex-

posure during the tasks of mixing/loading

to be determined separately from the ex-

posure during the application. The handling

of the concentrated pesticide during mix-

ing and loading generally results in greater

levels of exposure than the application pro-

cess. However this depends on the type of

containers or transfer mechanism used for

mixing and loading, as the size of the con-

tainer and the number of containers to be

handled is critical and varies greatly. In case

large greenhouses are to be treated, the

mixing and loading procedure of pesticides

is often done by workers not involved with

the application itself.

The data presented in Figure 1, concern-

ing a hand held, upward application tech-

nique, show potential dermal exposure as

ml/hour separately for the hands and the

body. The potential dermal exposure of

the hands was measured by placing cot-

ton gloves on the volunteer operators, so it

is a measure of the pesticide landing on the

hands, and not necessarily what would be

retained by hands or impermeable gloves.

These data are consistent with published

data for potential dermal exposure for the

hand held, upward application technique.

The majority of the data for potential dermal

exposure excluding hands are between 60

and 120 ml/hour. The data are variable, with

coefficient of variation of 122% for the hands

and 139% for the rest of the body. Data in

the German model (Lundehn

et al.

, 1992) for

an equivalent application technique have a

coefficient of variation of 149%.

Several studies have been carried out

in Greece concerning indoor and outdoor

hand held application of pesticides yield-

ing data for potential dermal exposure ex-

pressed in ml spray solution/hour (Machera

et al.

, 2001; Machera

et al

., 2002; Machera

et

al.,

2003). Recent studies have provided the

exposure levels in mg/kg a.i as expressed in

the German Model. Two of them involved

outdoor application in olives and vines in-

dicating a potential dermal exposure be-

tween 61-317 mg/kg a.i. with the respective

value calculated by the German model be-

ing 189 mg/kg a.i. The other two of them in-

volved greenhouse trials, hand held applica-

tion techniques with either spray guns or 4

nozzle lances fed by hoses at 25 bar pump-

ing pressure. In the first greenhouse study

with 11 operators using spray guns and two

types of protective coveralls the potential

dermal exposure ranged from 8.4 to 664.1

mg/kg a.i. applied, with a mean of 179.3 and

a coefficient of variation of 112%. The low-

est value was obtained with an application

where the operator walked backwards away

from the spray cloud. In the same study the

data indicate that the potential dermal ex-

posure measured (mg/kg a.i., 50% percen-

tile) was 5-6 times the value estimated by

Figure 1.

Data for potential dermal exposure of hands and

body (ml/hour).