Emerging techniques in food science: the resistance of chlorpyrifos pesticide pollution against arc and dielectric barrier discharge plasma

Many studies introduced cold plasma as a novel and effective processing technology for microbial decontamination of food and water as well as for the removal of environmental pollution such as pesticide. However, as there are several types of plasma designs, their efficacy in degrading major pesticide residues, such as chlorpyrifos (as a hazardous chemical), should be explored. This study was conducted to assess the decontamination efficacy of 8 min of arc and dielectric barrier discharge (DBD) plasma on chlorpyrifos pesticide-water samples at a concentration of 2 mg·L-1. The plasma-treated samples were assessed by liquid chromatography-mass spectrometry (LC-MS) and compared with the control (untreated) sample. In addition, the effects of plasma processes on some physical properties of samples were studied. According to the results, plasma-treated samples showed similar physical characteristics (e.g., refractive index and color values) to those of the untreated samples. While the temperature of the samples remained steady during the DBD plasma treatment, arc plasma changed the temperature of the sample at a rate of about 3.75°C·min–1 and yielded a sample with a final temperature of 60°C. However, contrary to the general belief that plasma is an efficient technique for pesticide degradation, chemical analyses showed high resistance of chlorpyrifos against both arc and DBD plasma under the conditions used in the present study. Therefore, the possibility of high resistance of pesticide pollution to this emerging technology should be considered. Also, further studies on the efficiency of the selected plasma system for removing pesticide pollution (e.g., during water and wastewater treatment) at industrial scale is needed.