Ambient air concentrations of plant protection products: Data collection for the combined air concentration database and associated risk assessment.

CropLife Europe collected literature values from monitoring studies measuring air concentrations of Plant Protection Products (PPPs) that may be inhaled by humans located in rural areas but not immediately adjacent to PPP applications. The resulting "Combined Air Concentration Database" (CACD) was used to determine whether air concentrations of PPPs reported by the French "Agency for Food, Environmental and Occupational Health & Safety" (ANSES) are consistent with those measured by others to increase confidence in values of exposure to humans. The results were put into risk assessment context. Results show that 25-90% of samples do not contain measurable PPP concentrations. Measured respirable fractions were below EU default air concentrations used for risk assessment for resident exposure by the European Food Safety Authority. All measured exposures in the CACD were also below established toxicological endpoints, even when considering the highest maximum average reported concentrations and very conservative inhalation rates. The highest recorded air concentration was for prosulfocarb (0.696 µg/m³ measured over 48 h) which is below the EFSA default limit of 1 µg/m³ for low volatility substances. In conclusion, based on the CACD, measured air concentrations of PPPs are significantly lower than EFSA default limits and relevant toxicological reference values.

A comparison between field measurements of vapour concentrations of plant protection products and predictions by the BROWSE model.

A database of field measurements of air concentrations of pesticide active ingredients has previously been compiled by CropLife Europe with an aim to revise the default air concentration values and assumptions applied in assessing vapour exposure in the risk assessment of bystanders and residents. The BROWSE model, released in 2014, which is a regulatory risk assessment model that includes the exposure of residents and bystanders has a component relating to post-application vapour inhalation. Predictions of concentration deduced from exposures obtained using the BROWSE model were compared with field measurements of 24-h and 7-day average concentrations. The methodology for obtaining concentration estimates from the BROWSE model is described, and the criteria for including field studies in the comparison are given. The field data were adjusted to account for differences between the field experiment and the BROWSE scenario using factors derived from a separate plume dispersion model. This showed that BROWSE provides a satisfactory level of conservatism in determining potential exposures of residents and bystanders to vapour and could be a reliable alternative to replace the current EFSA approach for predicting vapour inhalation exposures for pesticides where no compound-specific data are available.

Measured air concentrations of pesticides for the estimation of exposure to vapour in European risk assessments.

There is an identified need to revise the default air concentration values and assumptions applied in assessing vapour exposure in the risk assessment of bystanders and residents to plant protection products. To address this, we evaluated inhalation exposure via vapour using previously unpublished data from 29 field and wind tunnel studies. The database comprises 35 trials with 11 active ingredients covering a wide range of scenarios with respect to vapour pressure, crops, application rates and European regions. Of the 961 individual measurements, 634 were below the Limit of Detection (LOD), 282 were between the LOD and Limit of Quantification (LOQ) and only 45 (4.7%) were quantifiable. Ten individual non-normalized samples exceeded 0.1 µg/m³. Of the 81 first-day measurements after the application, 36 were

Review of air concentrations of pesticides for estimating exposure to vapour in European risk assessments.

In current European non-dietary risk assessment for bystanders and residents, one of the plant protection product exposure pathways to be addressed is vapour inhalation. At present, active ingredients are grouped according to vapour pressure and assigned corresponding values. Risk assessments are driven by only two default air concentration values. Sampling is inconsistent, background data are sparse and many factors having an impact on air concentrations are not considered. Within the changing regulatory landscape over the last 20 years, criteria for volatility grouping and consequently for vapour exposure estimation have been applied heterogeneously. Here we review the background data currently used in the exposure assessment guidance to demonstrate the arbitrary nature of derived air concentration values and their inconsistent application in exposure assessment. In doing so we discuss air concentration from a risk assessment perspective and how active ingredients are grouped according to vapour pressure. We examine the database which at present forms the basis for predicting inhalation exposure to PPPs, particularly the two concentration levels driving risk assessments, and we discuss several other factors having an impact on air concentration. In conclusion, we recommend an urgent revision of the default air concentration values and assumptions applied in assessing vapour exposure.