Environmental Monitoring and Contaminants Research Vol.1, pp.17–27 (2021) DOI: https://doi.org/10.5985/emcr.20200004 Environmental Monitoring & Contaminants Research Environmental Monitoring and Contaminants Research Vol.1, pp.17–27, 2021 https://emcr-journal.org/ Article Contamination levels, monthly variations, and predictions of neonicotinoid pesticides in surface waters of Gifu Prefecture in Japan Yoshitaka HAYASHI1), Nozomi SASAKI2), Mari TAKAZAWA3)＊, Tomomi INAGAKI4), Hiroki NAKAMURA4), Atsushi YAMAMOTO1) and Shigeru SUZUKI1) 1) Graduate School of Bio Sciences and Bio Technologies, Chubu University, 1200 Matsumoto, Kasugai City, Aichi Prefecture 487-8501 Japan 2) School of Public Health, Department of Environmental Health Science, University at Albany, State University of New York, 1400 Washington Avenue, Albany, New York 12222 USA 3) Water Environment Research Group (Water Quality), Public Works Research Institute, 1-6 Minamihara, Tsukuba City, Ibaraki Prefecture 305-8516 Japan 4) Gifu Research Center for Public Health, 4-6 Akebono, Gifu City, Gifu Prefecture 500-8148 Japan [Received September 28, 2020; Accepted November 5, 2020] ABSTRACT The neonicotinoid pesticides acetamiprid (ACE), clo- thianidin (CTD), dinotefuran (DIN), imidacloprid (IMI), ni- tenpyram (NTP), thiacloprid (THI), and thiamethoxam (TMX) are widely used in over 120 countries. These pesti- cides have been regulated in many jurisdictions, including the European Union (EU), the United States, and the United Kingdom, due to adverse effects on non-target organisms, whereas some of these pesticides are permitted in Japan. In the present study, we have 1) measured levels of these pesti- cides at 103 locations (n = 672) across Gifu Prefecture, 2) analyzed the monthly trends and regionality using R and ArcGIS, and 3) created a predicted contamination map by an ordinary kriging analysis. The concentration levels of the seven neon- icotinoid pesticides in surface waters were determined using liquid chromatography with tandem mass spectrometry (LC/ MS/MS) and ranged from < 2.0 to 530 ng/L during the ten-month period. In a total of 672 samples, the top three pesticides detected at high frequency were DIN (76.9%), CTD (48.4%), and IMI (19.6%). The concentration of the neonicotinoid pesti- cides in environmental waters varied with the time periods of application, physiochemical properties of the pesticides, land use, geological properties of the contamination sources, and other factors. Potential contamination sources were depicted in the predicted contamination maps by using ordinary kriging models, which showed that DIN and CTD are widely pres- ent in Gifu Prefecture. Monthly variance of the concentration of IMI differed in the two geological regions, due to differenc- es in the time of application and agricultural products yield. The results of our study contribute to a better understanding of the contamination status of neonicotinoid pesticides by providing reference data (actual pesticide concentrations) as well as predicted contamination maps. Key words: neonicotinoid pesticide; surface water; Gifu Prefecture; predicted contamination; environmental behavior; dinotefuran flowers and fruits (National Institute for Environmental INTRODUCTION Studies, 2018). The seven major neonicotinoid pesticides are Neonicotinoid pesticides are currently the most widely acetamiprid (ACE; CAS RN®: 160430-64-8), clothianidin (CTD; used class of pesticides in over 120 countries (Simon-Delso et CAS RN®: 210880-92-5), dinotefuran (DIN; CAS RN®: 165252- al., 2015). In Japan, an estimated 431 tons of neonicotinoid pes- 70-0), imidacloprid (IMI; CAS RN®: 138261-41-3), nitenpyram ticides were used in 2018 in the production of rice, vegetables, (NTP; CAS RN®: 150824-47-8), thiacloprid (THI; CAS RN®: 111988-49-9) , and thiamethoxam (TMX; CAS RN®: 153719-23- ＊ Corresponding Author: [email protected] 4) , all of which are hydrophilic in nature (Chemicalize, 2020). This article is licensed under a Creative Commons [Attribution These pesticides dissolve in water and enter vegetation 4.0 International] license. © 2021 The Authors. through the roots, and, in small quantities, these pesticides are 17 Japan Society for Environmental Chemistry Neonicotinoid concentrations in surface waters effective insecticides (Wood and Goulson, 2017). Nicotinoids Chemical Co., Inc. (Tokyo, Japan). Pure water ( ≤ 0.5 μS/m) are considered to be less toxic to vertebrates than other com- was purchased from ADVANTEC (Tokyo, Japan). Solid phase monly used pesticides and are relatively safer for the environ- extraction cartridges (InertSep Slim-J Pharma FF, 230 mg), ment (Nauen et al., 2001; Tomizawa and Casida, 2005) due to and graphite carbon-SPE cartridges (InertSep Slim-GC, 400 their specific mode of action as inhibitors of insect nicotinic mg) were purchased from GL Sciences (Tokyo, Japan) and acetylcholine receptors (nAChRs) (Palmer et al., 2013). How- both were conditioned with 5 mL acetone and 10 mL pure ever, the findings of prior studies suggest that these pesticides water prior to use. L-column 2 (2.1 mm × 150 mm, 3 μm) was may have adverse direct or indirect effects on children and purchased from Chemicals Evaluation and Research Institute non-target organisms in the environment (Hallmann et al., (Tokyo, Japan). 2014; Blacquière et al., 2012; Millot et al., 2017; Van Dijk et al., 2013; Han et al., 2018; Woodcock et al., 2016; Gupta, 2018). SAMPLE COLLECTION AND EXTRACTION Due to the adverse effects of neonicotinoid pesticides, the Surface water samples were collected at 37 locations of governments of several European countries and the United seven major river systems (Ibi-, Jintsuu-, Kiso-, Nagara-, Shou-, States (US) have established restrictions. The governments of Shonai-, and Yahagi-river) and 66 locations in their tributaries the US and the United Kingdom restricted the use of all neon- (n = 672) in Gifu Prefecture, Japan, from May 2016 to February icotinoid pesticides in 2017 (US Congress, 2017; Department 2017 (Fig. S1). The samples were collected after the approval for Environment, Food and Rural Affairs, 2017). In 2018, the of local laws, and the GPS coordinates of the sampling loca- European Union (EU) banned all outdoor uses of the three ne- tions are given in Table 1. All water samples were collected at onicotinoid pesticides (CTD, IMI, and THI) (European Com- the surfaces of the center streams and stored in polypropylene mission, 2018). In contrast, Japanese regulators, with the aim bottles in a refrigerator at 4°C until sample extraction. of promoting widespread application of neonicotinoids in agri- The extraction procedure of the neonicotinoid pesticides cultural production, had loosened relevant laws in 2015 (Minis- in surface water is shown in Fig. S2. The pesticides in the sam- try of Health, Labour and Welfare, 2015) and in 2017 (Ministry pled water were collected by passing 250 mL of the water of Health, Labour and Welfare, 2017). Therefore, particularly through an InertSep Slim-J Pharma FF cartridge (Pharma in Japan, evaluating the effects of neonicotinoid pesticides on FF). After loading the samples, an InertSep Slim-GC (Slim-GC) human bodies, organisms, and the environment is important. cartridge was connected to the exit of the sample containing There have been a number of reports in Japan of contami- Pharma FF, the pesticides were eluted by passing 5 mL ace- nation from these pesticides in surface waters (Yamamoto et tone through the Pharma FF connected to the Slim-GC. The al., 2012; Sato et al., 2016; Nishino et al., 2018), effluents eluted solution was collected in a glass tube and concentrated (Nishino et al., 2018), tap water (Sato et al., 2016; Kamata et al., to 0.1 mL or less under a gentle stream of nitrogen gas. The 2020), and underground water sources (Hayashi et al., 2017). concentrated solution was reconstituted with ACN/water Due to the hydrophilic nature of nicotinoids, there is the possi- (1/9, v/v) to 1 mL, and 1 μL of this solution was applied to bility that these pesticides, when applied to agricultural fields, LC/MS/MS measurement. will enter the environment through runoff (Pietrzak et al., 2020). Most of the agricultural fields in Japan are used to grow INSTRUMENTAL CONDITIONS rice, and 70% of these are “wet fields.” (Ministry of Agriculture, The pesticides were analyzed by selected reaction moni- Forestry and Fisheries, 2019). Thus, runoff of hydrophilic pes- toring (SRM) with an API5500 electrospray tandem quadru- ticides from rice paddy fields is a major concern when examin- pole mass spectrometer (Sciex Pte., Ltd., Framingham, MA, ing contamination of the aquatic environment. USA) interfaced with LC800 HPLC systems (GL Sciences Inc., In this study we carried out a monthly survey (over 10 Tokyo, Japan) equipped with L-column 2 and mobile phase of months) of the occurrence of seven neonicotinoid pesticides ACN and 0.1 v/v% formic acid in water. The details of the in- (ACE, CTD, DIN, IMI, NTP, THI, and TMX) in surface waters strumental parameters are presented in Table S1. Analyte at 103 locations in seven river systems across Gifu Prefecture. peaks were identified with the retention times ( ± 0.05 min), We found that nicotinoids had been widely applied to rice pad- and the ratio of quantitative to quantitative transition-ion re- dy fields, vegetable fields, orchards, and golf courses. We used sponses ( ± 20%) as well as predefined sets of SRM transitions. geostatistical analysis (ArcGIS) with ordinary kriging to obtain ACE, TMX, and IMI were quantified with