Effects of temperature on the dissipation of total- and water-extractable pesticides in Japanese soils

Abstract

We investigated the dissipation of 27 pesticides in five Japanese soils at three temperatures and the variability of activation energies (E a). The dissipation of total pesticides extracted sequentially using water and acetone was fitted to a single first-order (SFO) model. The E a values calculated from the dissipation rate constants of the SFO model showed a normal distribution with a median of 61.1 kJ mol −1. The dissipation of water-extractable pesticides (i.e., phytoavailable pesticides) was fitted to a double firstorder in parallel model with two dissipation rate constants: k 1 and k 2. The E a values calculated from k 1 and k 2 showed normal or lognormal distribution, and the medians of the normal distribution calculated from k 1 and k 2 were 62.8 and 45.2 kJ mol −1 , respectively. Furthermore, the method for estimating the biphasic dissipation of phytoavailable pesticides at different temperatures by using the median E a values of the laboratory experiment was demonstrated in a field experiment.

Performance evaluation of lysimeter experiments for simulating pesticide dissipation in paddy fields. Part 1: Submerged application of granular pesticides

“…Ok et al 28) reported that the DT 50 s of butachlor and pyrazosulfuron-ethyl in paddy water tested in the summer crop season were faster than those tested in the summer. Meanwhile, Motoki and Iwafune 29) found that the time-dependent increase in K d of flutolanil became higher as the incubation temperature increased. In 2012 and 2014, the average water temperatures in paddy fields were 2.5-6.0°C higher than those in the lysimeters, whereas the average water temperatures in both the lysimeters and paddy fields were similar in 2015 (see Supplemental Table S6).…”

Relationship between the Vertical Distribution of Pesticides, Including Neonicotinoids, in Soils and Their Uptake by Brassica rapa L. var. peruviridis

“…The daily mean temperatures during the period of 42 days after pesticide application were 27 and 23 °C for EX-1 and EX-2, respectively. Because the dissipation rates of pesticides increase with temperature, 42,43 the temperature was not the main factor responsible for the annual variation of the dissipation rates of THI and FOS in the soil. However, the mean moisture contents of soil samples (0−10 cm depth) during the 42 day period were 42% and 50% of WHC for EX-1 and EX-2, respectively; thus, the high-soil moisture conditions may have accelerated the dissipation of pesticides in soil as previously reported.…”

PESTIPOND: A descriptive model of pesticide fate in artificial ponds: II. Model application and evaluation

“…These results support the link between temperature, HRT, and pesticide behavior. Higher temperatures enhance the microbial activity behind the biotransformation and are accompanied by important solar radiations, which favors photolysis (Kaur and Vishnu, 2022;Law et al, 2014;Motoki et al, 2020;Rani and Sud, 2015). Therefore, significant pesticide transformation was noticed during periods of high temperature.…”