Quantitative risk assessment of skin sensitising pesticides: Clinical and toxicological considerations

Legislation and Current Practices Concerning Risk Assessment of Skin Sensitizers in the European Union: A Comparative and Survey Study

BACKGROUND

Despite legislation aimed to protect the population against skin sensitization in the European Union (EU), over one quarter of the general population is sensitised to at least one chemical.

OBJECTIVES

To provide an overview and comparison of European legislation concerning skin sensitization. In addition, we gathered the opinions of experts and stakeholders regarding improvements in the legislation and risk assessment process in the EU, to provide suggestions for improvement.

METHODS

Legislation was identified and compared. Four questionnaires were created towards industry, competent authorities and regulators, researchers/clinicians, and non-governmental organisations. The questions concerned the legislation, the risk assessment process, data collection and potential improvements.

RESULTS

Seven areas of legislation were analysed. The legislation was found to be unharmonised, for example, differing modes of restriction and accepted tests for skin sensitization. Approximately 40% of the questionnaire respondents found that the EU legislation and tools were not sufficiently protective. To improve the legislation 83% suggested harmonisation and 68% suggested better data sharing. Other areas were: improved exposure data (78%), better understanding of the skin sensitization mechanism (67%) and non-animal tests (66%).

CONCLUSIONS

Stakeholders had varying confidence towards the protection of European citizens against skin sensitization. Multiple areas for improvement regarding the legislations and the risk assessment process were identified.

GARD™skin and GARD™potency: A proof-of-concept study investigating applicability domain for agrochemical formulations

Several New Approach Methodologies (NAMs) for hazard assessment of skin sensitisers have been formally validated. However, data regarding their applicability on certain product classes are limited. The purpose of this project was to provide initial evidence on the applicability domain of GARD™skin and GARD™potency for the product class of agrochemical formulations. For this proof of concept, 30 liquid and 12 solid agrochemical formulations were tested in GARDskin for hazard predictions. Formulations predicted as sensitisers were further evaluated in the GARDpotency assay to determine GHS skin sensitisation category. The selected formulations were of product types, efficacy groups and sensitisation hazard classes representative of the industry's products. The performance of GARDskin was estimated by comparing results to existing in vivo animal data. The overall accuracy, sensitivity, and specificity were 76.2% (32/42), 85.0% (17/20), and 68.2% (15/22), respectively, with the predictivity for liquid formulations being slightly higher compared to the solid formulations. GARDpotency correctly subcategorized 14 out of the 17 correctly predicted sensitisers. Lack of concordance was justifiable by compositional or borderline response analysis. In conclusion, GARDskin and GARDpotency showed satisfactory performance in this initial proof-of-concept study, which supports consideration of agrochemical formulations being within the applicability domain of the test methods.

Use of guinea pig data to obtain starting points for skin sensitisation risk assessment - A commentary

The increasing drive to understand the likelihood of skin sensitisation from plant protection products (PPPs) in workers and the general public has resulted in recent initiatives to establish a quantitative risk assessment (QRA) methodology applicable to these products and their exposure scenarios. The effective evaluation of skin sensitising substances requires not only the identification of that toxicological hazard, but also determination of relative sensitising potency. Typically, this has been achieved by interpretation of local lymph node assay (LLNA) dose response data, delivering what is known as the EC3 value. This permitted regulatory division of skin sensitisers into defined potency sub-categories, but more importantly enabled derivation of a no expected sensitisation induction level (NESIL) as the point of departure for QRA. However, for many existing substances there is no LLNA data, only older guinea pig results exist. To avoid additional (in vivo) testing, an approach has been outlined to employ guinea pig data and existing regulatory guidelines on the determination of potency sub-categorisation to provide a guinea pig based NESIL. The approach adopts a conservative extrapolation from LLNA NESIL benchmarks to deliver points of departure as the basis for the type of QRA process already in successful use by other industries.