The pollinator risk assessment framework laid out by US EPA, PRMA, and CDPR (2014) is primarily focused on pesticide active ingredients. In recent years, there has been increased interest in the potential impact, if any, to human health and the environment of inert ingredients (i.e., non-pesticidally active components of pesticide products) and chemical substances used as tank mix adjuvants and surfactants. Trisiloxane polyethers represent a class of superspreader surfactants with the unique ability of significantly reducing the surface tension of water to promote a rapid spreading of aqueous solutions on the surfaces of leaves. Since limited data is available regarding routes of exposure to honeybees from trisiloxanes, there are some challenges in the evaluation of exposure characterization. The objective of this presentation is to layout the challenges in the exposure characterization of three trisiloxane polyether surfactants and discuss various methodologies employed to conservatively quantify exposure for use in a screening-level pollinator risk assessment framework for these surfactants. The BeeREX Tier I screening-level risk assessment model uses maximum application rates to estimate worst-case exposure concentrations in various honeybee matrices via model default residue assumptions, for instances where available residue data are not available. The model also provides a refinement option using available residue data. The CDPR Pesticide Use Registry (PUR) database was used to determine reasonable maximum surfactant application rates, which were modeled to determine worst-case exposure rates using default residue assumptions. In addition, refined exposure estimates were determined by incorporating surfactant residues generated in a field residue study.

Screening-level pollinator risk assessment for trisiloxane polyether surfactants (Part I): Challenges and methodologies for estimating exposure of honeybees (<i>Apis mellifera</i>)

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Screening-level pollinator risk assessment for trisiloxane polyether surfactants (Part I): Challenges and methodologies for estimating exposure of honeybees (Apis mellifera)