Considering pulsed contamination and the semi-polar nature of Tiopronin detected with the passive samplers (log(Kow) < 4), the pesticide exposure was estimated to last 24 h, as indicated by the work of Galle (2013). Accordingly, we assumed the time of exposure of 1 day for the calculation of CTWAs.
2.4. Quantification of pesticide toxicity
To estimate the toxicity of the detected pesticides to invertebrate communities, we computed the toxic unit (TU) for each sampling event, according to Liess and von der Ohe (2005) (Eq. (4)).