Report on the Health Effects of Selected Pesticide Coformulants

Report on the Health Effects of Selected Pesticide Coformulants

Summary

Coformulants are widely used in the formulation of pesticides and thus constitute a potential health risk to humans through exposure to pesticides. In 1999, the Bichel Committee expressed concern that coformulants in some cases were more acutely toxic than the active substances in plant protection products and recommended that the approval system for plant protection products should also include data requirements on coformulants. The committee also recommended considering a ban of carcinogenic coformulants.

This project aims at compiling the available data and assessing the toxicological effects of selected coformulants in order to create at basis for decision making with respect to the possible need to revise the existing legislation. The effects of eighteen pesticide coformulants are assessed for adverse health effects on the basis of available literature. The substances for this project have been selected primarily on the basis of their tonnage on the market, but a number of exclusion criteria were also taken into account in the prioritisation.

The results of this project demonstrate that the data availability for the 18 selected coformulants is limited. Toxicological data are available for 16 of the selected coformulants; for 2 of these coformulants, relevant data are only available for acute toxicity and irritation. For the remaining 2 coformulants, no relevant data are available at all. The database for the individual substances consisted primarily of animal data, as human data were scarce and often of questionable quality and/or relevance. The data found related predominantly to acute toxicity and irritative effects, and only few data were located on sensitisation, repeated dose toxicity, toxicity to reproduction, and carcinogenicity. Furthermore, for many of the coformulants, various endpoints have not been examined thoroughly although data are available. In conclusion, the hazard assessments of most of the selected coformulants may be hampered by the data gaps identified.

The hazard assessments of the selected coformulants showed a number of toxicological effects of the substances. Many of the substances were irritative to the skin, eyes and respiratory tract. Serious effects were reported on some of the coformulants including neurological effects, CNS depression, sensitisation, haemolytic effects, and nephrotoxicity. One coformulant is probably a developmental toxicant following exposure at very high concentrations. For none of the selected coformulants, a carcinogenic potential has been identified; however, data are only available for 10 of the selected coformulants for this end-point.

The scope of the project is too limited to make general conclusions on toxicity and data availability on coformulants. Also, the criteria for the prioritisation of the coformulants in this projects give rise to some bias regarding the representativity of the results obtained and thus, it is not known whether the conclusions made based on the 18 selected substances can be extended to the large number of coformulants used. However, the data indicate that coformulants are not toxicologically inert, but in some cases even have serious adverse health effects.
It should be noted that a proper risk assessment cannot be performed for the selected coformulants as no exposure assessments have been carried out in this project, which only has focused on hazard assessment. Thus, no conclusions can be made exclusive based on the results obtained in this project whether exposures to these coformulants in pesticides may constitute a risk for humans of experiencing adverse health effects during the use of these pesticides.

On the basis of the results obtained in this project, it is recommended that the authorities take further measures to ensure that humans are protected from experiencing adverse health effects following exposure to coformulants used in pesticide formulation. A revision of the current approval scheme in order to include data requirements on all relevant toxicological end-points for either the coformulants or the pesticide coformulations could be considered in order to enable a detailed hazard assessment of every end-point of relevance to human health. Another measure could be a further regulation on the use of coformulants in pesticide formulations, i.e., to prohibit the use of coformulants for which serious health effects are identified.