Sammanfattning

Systemic neonicotinoid insecticides such as imidacloprid are increasingly applied against insect pest infestations on forest trees. However, leaves falling from treated trees may reach nearby surface waters and potentially represent a neonicotinoid exposure source for aquatic invertebrates. Given imidacloprid's susceptibility towards photolysis and high water solubility, it was hypothesized that the leaves' toxicity might be modulated by UV-irradiation during decay on the forest floor, or by leaching and remobilization of the insecticide from leaves within the aquatic ecosystem. To test these hypotheses, the amphipod shredder Gammarus fossarum was fed (over 7 d; n = 30) with imidacloprid-contaminated black alder (Alnus glutinosa) leaves that had either been pre-treated (i.e., leached) in water for up to 7 d or UV-irradiated for 1 d (at intensities relevant during autumn in Central Europe) followed by a leaching duration of 1 d. Gammarids' feeding rate, serving as sublethal response variable, was reduced by up to 80% when consuming non-pretreated imidacloprid-contaminated leaves compared to imidacloprid-free leaves. Moreover, both leaching of imidacloprid from leaves (for 7 d) as well as UV-irradiation reduced the leaves' imidacloprid load (by 46 and 90%) thereby mitigating the effects on gammarids' feeding rate to levels comparable to the respective imidacloprid-free controls. Therefore, natural processes, such as UV-irradiation and re-mobilization of foliar insecticide residues in water, might be considered when evaluating the risks systemic insecticide applications in forests might pose for aquatic organisms in nearby streams. (C) 2018 Elsevier Ltd. All rights reserved.

Nyckelord

Neonicotinoids; Imidacloprid; Gammarus; Leaf fall

Publicerad i

Environmental Pollution
2018, Volym: 236, sidor: 119-125
Utgivare: ELSEVIER SCI LTD

SLU författare

• Bundschuh, Mirco

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    
  • Universität Koblenz-Landau

Associerade SLU-program

SLU Nätverk växtskydd


Globala målen

SDG6 Säkerställa tillgången till och en hållbar förvaltning av vatten och sanitet för alla
SDG3 Säkerställa hälsosamma liv och främja välbefinnande för alla i alla åldrar


UKÄ forskningsämne

Miljövetenskap


Publikationens identifierare

DOI: https://doi.org/10.1016/j.envpol.2018.01.050

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/98136