Modeling Remobilization of Neonicotinoid Residues from Tree Foliage in Streams-A Relevant Exposure Pathway in Risk Assessment?

Abstract

Systemic neonicotinoid insecticides are increasingly used as a crop protection measure to suppress insect pests on trees. However, senescent foliage falling from treated trees represents a rarely studied pathway through which neonicotinoids may enter nontarget environments, e.g., surface waters. To estimate risk posed by this pathway, neonicotinoid residues were analyzed in foliage from black alder trees treated with one of three neonicotinoid insecticides (imidacloprid, thiacloprid, or acetamiprid) at five concentrations, each ranging from 0.0375-9.6 g active ingredient/cm trunk diameter at breast height (n = 3). Foliar residues measured at the time of leaf fall were used as input parameters for a model predicting imidacloprid water concentrations over a 100-m-long stream stretch as a consequence of remobilization from introduced foliage (input: 600 g foliage/m(2) containing 80 mu g imidacloprid/g). The water concentration (up to,similar to 250 mu g/L) predicted by the model exceeded the recently proposed Maximum Permissible Concentration of 8.3 mu g/L for 15.5 days. Moreover, dietary uptake was identified as an additional exposure route for aquatic organisms. The alternative pathway (i.e., introduction via leaf fall) and exposure route (i.e., dietary uptake) associated with the systemic nature of neonicotinoids should be accounted for during their registration process in order to safeguard ecosystem integrity.

Published in

Environmental Science and Technology
2017, Volume: 51, number: 3, pages: 1785-1794

SLU Authors

• Bundschuh, Mirco

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


Sustainable Development Goals

SDG3 Good health and well-being
SDG6 Clean water and sanitation


UKÄ Subject classification

Other Natural Sciences not elsewhere specified


Publication identifier

DOI: https://doi.org/10.1021/acs.est.6b05213

Permanent link to this page (URI)

https://res.slu.se/id/publ/86675