**1. Introduction**

Pesticides sprayed on crops attach to their surfaces, fall to the soil, and either remain in the soil or transported to water systems [1,2]. Pesticides decompose and dissipate over time through various physico-chemical and biological processes, but in some cases a significant amount of the pesticide can be introduced into the soil, resulting in soil contamination. When plants are grown in contaminated soil, trace amounts of pesticides can be taken up by the plant roots and transferred to other parts of the plant [3,4], leading to pesticide contamination of the plants. Leafy vegetables and leaf-and-stem vegetables are more prone to this type of contamination compared to fruits, as they have a higher chance of accumulating pesticides due to their edible parts [5–7]. This accumulation can result in unintentional contamination of agricultural products and pose health risks to consumers.

Fluopyram is a benzamide-based fungicide that inhibits the function of succinate dehydrogenase (SDH) inside the mitochondrial membrane, thereby controlling pathogenic fungi in plants [8]. Fluopyram is widely used in Korea to control fungal growth, such as grey mold (*Botrytis*) and powdery mildew in fruits and vegetables. The organic carbon adsorption coefficient for fluopyram (Koc), which is a representative indicator of the mobility

**Citation:** Yun, M.-S.; Choi, H. Uptake of Fungicide Fluopyram from Soil by Scallions during Greenhouse Cultivation. *Foods* **2023**, *12*, 1996. https://doi.org/10.3390/ foods12101996

Academic Editors: Dapeng Peng, Massimo Castellari and Yongzhong Qian

Received: 26 March 2023 Revised: 8 May 2023 Accepted: 11 May 2023 Published: 15 May 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

of pesticides in soil, is 233–400 mL/g, indicating a moderate level of mobility [9]. Additionally, fluopyram is heat-stable and very stable during hydrolysis and photolysis in acidic, neutral, and alkaline conditions, and the half-life in soil was reported as 119 days [10]. Therefore, owing to high soil persistence and moderate mobility of fluopyram, there is a strong possibility that it would remain in the soil and be absorbed into crops. Furthermore, the Korean cropping system has the characteristics of a short uncultivated period and frequent continuous/mixed cultivation, which has increased the possibility of pesticide uptake and contamination of rotational crop plants. In a survey on pesticide residues conducted by the Korean Ministry of Agriculture, Food and Rural Affairs in 2019, the residual amount of fluopyram was the highest among 13 unregistered pesticides detected in scallions, a leaf-and-stem vegetable [11]. A positive list system (PLS) has been implemented to strengthen domestic pesticide safety management. In this system, the maximum residue limit (MRL) applies a standard legal limit of 0.01 mg/kg to all non-registered pesticides. As a result, unintentional contamination of agricultural products due to pesticides remaining in the soil has become a more considerable problem than before the implementation of PLS. Therefore, it is necessary to establish safety management standards for residual pesticides in the soil by evaluating the uptake and translocation of soil residual pesticides into crops.

Scallion (*Allium fistulosum*) belongs to the genus *Allium* of the Liliaceae family and is a major leaf-and-stem vegetable in Korea with a cultivation area of 17,170 ha and an annual production of 463,721 tons [12]. In addition, unintentional persistence of fluopyram has been reported for scallions, raising safety concerns [11]. To the best of my knowledge, there are no previous reports on the potential for fluopyram residues to be present in scallions as a result of uptake from soil. Therefore, this study assesses the uptake of the fungicide fluopyram from the soil by scallions and proposed a management concentration for fluopyram in the soil to ensure the safety of agricultural products. The residual patterns of fluopyram in soil and scallion were analyzed, and the bioconcentration factor (BCF) was calculated as the absorption rate of fluopyram into scallions.
