Presence of the β-triketone herbicide tefuryltrione in drinking water sources and its degradation product in drinking waters

Abstract

Triketone herbicides are becoming popular because of their herbicidal activity against sulfonylurea-resistant weeds. Among these herbicides, tefuryltrione (TFT) is the first registered herbicide for rice farming, and recently its distribution has grown dramatically. In this study, we developed analytical methods for TFT and its degradation product 2-chloro-4-methylsulfonyl-3-[(tetrahydrofuran-2-yl-methoxy) methyl] benzoic acid (CMTBA). TFT was found frequently in surface waters in rice production areas at concentrations as high as 1.9 μg/L. The maximum observed concentration was lower than but close to 2 μg/L, which is the Japanese reference concentration of ambient water quality for pesticides. However, TFT was not found in any drinking waters even though the source waters were purified by conventional coagulation and filtration processes; this was due to chlorination, which transforms TFT to CMTBA. The conversion rate of TFT to CMBA on chlorination was almost 100%, and CMTBA was stable in the presence of chlorine. Moreover, CMTBA was found in drinking waters sampled from household water taps at a similar concentration to that of TFT in the source water of the water purification plant. Although the acceptable daily intake and the reference concentration of CMTBA are unknown, the highest concentration in drinking water exceeded 0.1 μg/L, which is the maximum allowable concentration for any individual pesticide and its relevant metabolites in the European Union Drinking Directive.

Removals of pesticides and pesticide transformation products during drinking water treatment processes and their impact on mutagen formation potential after chlorination

“…That these TPs are very hydrophilic (log K ow < 0.1 at pH 7) most likely reduced Ratio of R PAC of TP to that of its parent pesticide in the present study. The recent increase of tefuryltrione use and its low acceptable daily intake suggest that tefuryltrione should be monitored in drinking water and source waters (Kamata et al 2017). Lin and Xing (2008) reported that the extent of adsorption of phenolic compounds to carbon nanotubes was in the order of phenol < catechol < pyrogallol, even though their log K ow were in the same order.…”

“…The implication is that possible health effects related to the induction of gene mutation would be small, even though these compounds are found in tap water. In contrast, the MFP of tefuryltrione has not yet been reported, but chlorination completely transforms tefuryltrione into 2-chloro-4-(methylsulfonyl)-3-[(tetrahydrofuran-2-ylmethoxy)methyl]benzoic acid (CMTBA) (Kamata et al 2017), and CMTBA is reportedly very stable during chlorination (Kamata et al 2017). Because CMTBA does not induce mutagenicity (Food Safety Commission Government of Japan 2009), the MFP of tefuryltrione is expected to be negative.…”

National trends in pesticides in drinking water and water sources in Japan

“…Tefuryltrione decomposes to form 2-chloro-4-(methylsulfonyl)-3-[(tetrahydrofuran-2-ylmethoxy) methyl] benzoic acid (CMTBA) upon chlorine treatment, at a high conversion rate, and CMTBA was frequently detected in treated water and tap water. (Kamata et al, 2017). Fipronil yields its sulfone or additional forms in chlorine treatment (Teerlink et al, 2017).…”

Performance comparison of dispersive solid-phase extraction and multiplug filtration cleanup methods for the determination of tefuryltrione in plant and environmental samples using UHPLC-MS/MS

“…Tefuryltrione, which has a low logK ow (2.62) and high water solubility [7], may impose potential risk to water resources. Recently, Kamata et al reported that tefuryltrione was found in river water with maximum concentration of 1.85 μg/L, and its degradation product, 2-chloro-4-methylsulfonyl-3-[(tetrahydrofuran-2-yl-methoxy)methyl]benzoic acid, existed extensively in drinking water [6]. Besides, diatoms were found to be most sensitive to herbicides that belong to the family of 4-hydroxyphenyl-pyruvate-dioxygenase inhibitors (including tefuryltrione), indicating its potential aquatic toxicity [8].…”

“…Tefuryltrione is now widely used for rice farming in Asian countries including China, Japan, and Korea . It has become quite popular and has begun replacing sulfonylurea herbicides, because of its brilliant herbicidal activity against sulfonylurea‐resistant weeds . However, the large quantity of tefuryltrione being used might not simply cause a high incidence of residual tefuryltrione in crops but might also lead to tefuryltrione dispersed or transferred to soil, and eventually into river systems by rainfall, leaching, or surface runoff, likely causing serial water pollution.…”