Handskers beskyttelsesevne ved arbejde med pesticider i jordbrugene, samt modeller for håndeksponering

Protective Ability of Gloves Used for Handling Pesticides in Agriculture, and Dermal Exposure Models

Summary and conclusion

In the risk assessment of pesticide handling in agriculture, carried out by the Danish Environmental Protection Agency, different models are used in estimating the dermal exposure to which spraying crew and people who work with sprayed plants (re-entry) are exposed to pesticides. There are only few Danish data for this area. Instead, one has to use models that are made under conditions aiming to be comparable with Danish conditions. British, German, Dutch, and by now, common European models are available. The models are generic models and do not consider specific local cultivation conditions. The models are regarded as being a starting point in the risk assessments and will ideally result in knowledge as to whether a pesticide, for which there has been an application for registration for a specific purpose, e.g. spraying in grain against fungus diseases, exposes the spraying crew to higher exposure than permitted.

The Danish Environmental Protection Agency has expressed a wish for better knowledge as to the protective ability of the glove types used in Danish agriculture, including greenhouses. Hand protection is important when handling pesticides. There is general agreement that 85-95% of the potential exposure to which a sprayer in agriculture is exposed, occurs at the filling of the spraying tank with pesticides. 5-15% of the potential exposure happens during the spraying of the tank liquid. 90-95% of the exposure that he gets on his whole body at the filling of the tank gets on his hands. Therefore, hand protection is an important factor in this working environment.

In studies performed under practical conditions with the fungicide Amistar (active ingredient azoxystrobin), long-sleeved nitrile gloves have given a hand protection of about 97% at the filling of a tank with a hydraulic boom sprayer in agriculture or at the filling of the spraying tank and subsequent spraying of the spraying liquid in a greenhouse with handheld equipment when the potential exposure was between 1 and 45 mg. In the interval from 50 µg to 1 mg potential exposure, the gloves gave 92% protection. When spraying with hydraulic boom sprayer in agriculture, the protection was 80%. This scenario showed a potential exposure up to 1 mg in the experiments.That is to say that the percentage glove protection depended on the level of potential exposure. The potential exposure is the dose that you totally get on the whole body, bare skin as well as clothes. The actual exposure is the exposure that reaches the skin, either by direct contact or through protective clothing.

Model experiments have shown that special attention must be paid at the change of protective gloves. The actual exposure increases if one touch the outside of an exposed glove with the bare hand.

This protective ability for nitrile gloves only applies if a new pair of gloves is used every day. It has appeared that pesticides probably entered the bare hand even at the opening of this long-sleeved glove round the actual protective glove material.

In the work with sprayed plants (re-entry) in greenhouses, we tested a light nitrile glove and a latex glove. The light nitrile glove gave a protection of 97% for a 2-hour period. The latex glove gave 93% protection. We could not measure any penetration of the light nitrile glove with azoxystrobin, but a 4% break-through was registered in the latex glove in a 2-hour period. For both glove types, we have explained the remaining 3% by the fact that this exposure was transferred to the bare hand when the gloves were taken off. To a great extent, this dose can be avoided by taking care when the gloves are taken off. The gloves must be regarded as disposable gloves for a period of 2 hours for re-entry work. 2 hours fit a working period when lunch and coffee breaks are to be taken. Furthermore, the latex gloves had inferior physical stability. 17 single gloves out of 57 pairs of latex gloves were damaged compared to 6 single light nitrile gloves after 2 hours.

It is important that information about the penetration of pesticides in protective gloves is available, when recommending gloves.

Hand exposure models for tank filling in agriculture (hydraulic boom sprayer):
5 mg potential exposure/kg a.i. handled
0.1 mg actual exposure/kg a.i. handled

Hand exposure models for spraying in agriculture (hydraulic boom sprayer):
0.15 mg potential exposure/kg a.i. handled
0.015 mg actual exposure/kg a.i. handled

Hand exposure models for tank filling and spraying in greenhouses (handheld spraying equipment):
25 mg potential exposure/kg a.i. handled
0,7 mg actual exposure/kg a.i. handled

For the risk assessment of re-entry in green houses, knowledge is required as to how much pesticide occurring loosely bound to the plant surfaces (DFR, dislodgeable foliar residue) one has to work with. For azoxystrobin this value varies according to culture, but a 90% percentile was found to be about 3 µg/cm²*kg a.i./ha within 24 hours after spraying.

For estimation of the potential hand exposure at re-entry work in greenhouses, transfer coefficients, TC, that are characteristic of the type of work performed are required together with DFR (dislodgeable foliar residue). TC’s for 15 cultures of ornamental potted plants (making cuttings, planting cuttings, nursing and prepare for packing and packing) and cucumbers (picking), was found to be 1,033 cm²/t at the 75% percentile.