Parameterization of a Brazilian scenario in the USEPA Pesticide in Water Calculator tool to estimate the environmental exposure of pesticide in surface waters

Abstract

The current pesticide registration process in Brazil is mainly hazard-based and does not consider exposure and therefore risk. However, the scenario prompted changes and discussions about risk assessments by Brazilian environmental regulatory agencies. The US Environmental Protection Agency's (EPA) Pesticide in Water Calculator (PWC) model is used as a regulatory tool for aquatic exposure assessment in Canada and the USA for exposure evaluation of agrochemical products; nevertheless, the available scenarios only consider North American local conditions. This work aims to demonstrate a parametrization of the PWC model for a Brazilian scenario, considering the active ingredient glyphosate and sugarcane agronomic practices. The estimated environmental concentrations (EECs) obtained were compared with two standard EPA scenarios. Essential parameter data to build a specific local scenario were collected from the literature and official Brazilian databases. The EECs (1-in-10 years) of glyphosate according to the conditions established were 1.427 μg L −1 (1st day), 0.382 µg L −1 (21st day), and 0.2027 µg L −1 (60th day). These values can be used as exposure elements in acute and chronic risk assessments considering the agricultural practices used in the developed scenario. A 4.45-fold and 1.28-fold difference was found comparing the 1-day (1-in-10 years) average concentration of the Brazilian scenario with two EPA standard scenarios. Such a difference may affect the outcome of risk assessments, affecting regulatory decisions. This demonstrates the importance of generating more realistic scenarios for Brazil, yielding surface water EECs that consider local conditions.

Qualitative analysis of the most locally relevant runoff and erosion parameters for constructing Brazilian scenarios

“…The CN had a major influence on EEC SW calculation, especially on Herbicide 2, which has a low K OC . This finding agrees with other publications that also consider the use of local scenarios in Latin America (D'Andrea et al, 2020; De Oliveira Kaminski & Viera, 2021). Because CN data are easily found for Brazil, it is highly recommended that they should be used on the modeling, as well as the slope, which can be taken from topography maps such as the ones available on the PronaSolos database (PronaSolos, 2022).…”

“…In an approach similar to that of De Oliveira Kaminski and Viera (2021), the estimated EECs were compared for Herbicides 1 and 2. In this study, all 12 corn scenarios were tested and compared with the results using local scenarios (UDI and ARA).…”

“…Nonetheless, it is important to assess whether there might be an under‐ as well as an overestimate of the EEC SW . De Oliveira Kaminski and Viera (2021) have evaluated this hypothesis by comparing two sugarcane standard scenarios (Louisiana and Florida) against the results of a local Brazilian scenario (Brotas, SP). The output was similar between the local Brazilian and the US Florida scenarios, whereas the EEC SW was four times higher in the Louisiana scenario than the Brazilian scenario, suggesting that care must be taken when using scenarios from other regions to avoid an overestimation of the exposure.…”

“…In general, scenario‐dependent models have been built for the regulatory agencies of the US (USEPA, 2022b) and the European Union (European Food Safety Authority [EFSA], 2013) in partnership with industry and academics, whereas for other countries, especially tropical regions, there is need for scientific knowledge development including potential adaptations especially regarding the development of local scenarios. The development of local scenarios is important to provide regulators with more locally relevant exposure estimates (Casallanovo et al, 2021; D'Andrea et al, 2020; De Oliveira Kaminski & Viera, 2021) after the generic screening tools are applied and additional mitigations are identified as needed.…”