Residual Level of Chlorpyrifos in Lettuces Grown on Chlorpyrifos-Treated Soils

Kyu-Won Hwang,Joon-Kwan Moon,Soo Yoo,Sung-Eun Lee

doi:10.3390/app8122343

Kyu-Won Hwang, Joon-Kwan Moon + Show 2 more

Open Access

https://doi.org/10.3390/app8122343

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Abstract

This study was conducted to investigate the residual loss of chlorpyrifos and the amount transferred to lettuce from soil. Field trials on lettuce were conducted in two different greenhouses located in Yongin (field 1) and Gwangju (field 2) in Korea. Soil and lettuce samples were collected on different days after the treatment of chlorpyrifos at two different levels. The initial residue of chlorpyrifos (0.86 and 2.31 mg/kg) in soils decreased to 0.06 and 0.18 mg/kg, respectively, at 36 days after treatment (DAT) in field 1, and the initial residue with values of 11.10 and 22.59 mg/kg decreased to 1.20 and 3.04 mg/kg, respectively, at 43 DAT in field 2. In field 1, the half-lives of chlorpyrifos were approximately 8.4 and 9.0 days for soils treated with 0.86 and 2.31 mg/kg, respectively, while in field 2, the half-lives of chlorpyrifos were approximately 18.7 and 13.9 days for soils treated with 11.10 and 22.59 mg/kg, respectively. Residue levels of chlorpyrifos on lettuce were 0.66–5.98% and 2.71–13.26% compared to the initial concentration in the soil. Therefore, the management guideline of chlorpyrifos for lettuce-cultivating soils could be suggested to be 0.75 mg/kg with regards to the Positive List System level of chlorpyrifos on lettuce of 0.01 mg/kg.

Highlights

Pesticides are generally utilized to manage agricultural pests, such as fungi, insects, and weeds, in order to increase crop productivity
We reported the decline in residue in the soil after treatment with chlorpyrifos at different application rates, as well as the level of chlorpyrifos in lettuce grown in the treated soil to ensure the safety of lettuce products
According to the analysis of standard solutions, 0.1 ng was determined as the limit of quantitation (LOQ), which was satisfactory for the residual analysis of chlorpyrifos

Summary

Introduction

Pesticides are generally utilized to manage agricultural pests, such as fungi, insects, and weeds, in order to increase crop productivity. Chlorpyrifos is one of the violating compounds that were not registered on the detected crops [10] These results could have been due to the use of an unregistered pesticide on the crops or translocation from soil contaminated with the pesticide because some of the detected pesticides were systemic chemicals [11]. The PLS has been used on unregistered pesticides for crops on a non-detected basis and the standard of non-detection in PLS is established as 0.01 ppm (mg/kg) or less In this regard, various reports have well-documented the levels of retained pesticides in crops/plants translocated from contaminated soils [12,13,14,15,16,17,18], especially for persistent organochlorine insecticides. We reported the decline in residue in the soil after treatment with chlorpyrifos at different application rates, as well as the level of chlorpyrifos in lettuce grown in the treated soil to ensure the safety of lettuce products

Materials and Methods

Results and Discussion

36 DATto the amount of