## 1 Introduction  
According to the definition in the document of the International Code of Conduct on Pesticide Management of the Food and Agriculture Organization of the United Nations (FAO), pesticides are chemical and biological substances or mixtures thereof that serve the function of repelling, destroying, and controlling pests and regulating plant growth [1]. Pesticides have played an important role in modern agricultural production, and according to their characteristics, they can improve crop yield and quality, making a huge contribution to the development of the entire green revolution [2]. There are various types of pesticides, which are used in agricultural production, such as acaricides, insecticides, herbicides, fungicides, etc. It has a wide range of applications globally. According to FAO's database, global agricultural pesticide use will total 3.7 million tonnes in 2022, an increase of 4 percent from 2021 and 13 percent from a decade ago. Global pesticide use in the last decade has increased by 121% for herbicides, 54% for fungicides, and 48% for insecticides. The top five countries in terms of global pesticide use are Brazil (801,000 tonnes), the UnitedStates (468,000 tonnes), Indonesia (295,000 tonnes), Argentina (263,000 tonnes), and China (236,000 tonnes) [3]. Improper use of pesticides can cause pesticide residues in water and food. This study showed that about 113 pesticide residues were found in drinking water samples from 31 countries around the world. Of these, 61 insecticide, 31 herbicide, and 21 fungicide residues were found [4]. Pesticide residues are also common in food. The report on pesticide residues in food published by the European Union showed that of the 87,863 samples analyzed, 3.9% exceeded the MRLs, of which 2.5% were non-compliant [5]. In China, more than 40,000 batches of 135 types of fruits and vegetables collected from 45 key cities were analyzed for pesticide residues. Among them, 81.6 percent of the samples were detected with pesticide residues, and 532 pesticides were detected 115,981 times [6]. Pesticide residues can enter the ecosystem through surface water and groundwater and pollute water bodies. In water bodies, pesticides negatively affect algae, protozoa, fungi, and bacterial species; chlorpyrifos, carbofuran, and DDT pesticides inhibit algal growth and photosynthesis; diuron inhibits bacterial metabolism at high concentrations; and propiconazole significantly inhibits mycelial and spore development [7]. Exposure to pesticide residues poses a serious threat to human health. Human exposure to triazine herbicides can cause endocrine disorder [8], heart disease [9], and other symptoms [10]. Human exposure to sulfonylurea herbicides can induce hypoglycemia [11] and cardiovascular disease [12]. Human exposure to organophosphorus insecticides may cause general malaise, fatigue, headache, poor memory, concentration, anorexia, nausea, and other symptoms [13; 14; 15]. Human exposure to organochlorine pesticides can produce symptoms such as blindness, confusion, convulsions, and chronic bronchitis [16; 17; 18]. In recent years, there have been physical, chemical, and biological methods to solve the problem of pesticide residues. Table 1 shows a comparison of the different methods of treating pesticide residues. Chlorine dioxide and ozone are typical green oxidants that react with organic matter with high efficiency and do not produce harmful substances such as trihalomethanes [19; 20]. In addition, chlorine dioxide and ozone can react with organics in both gaseous and solution forms compared to traditional chemical oxidation techniques. Chlorine dioxide and ozone have low treatment costs and are widely used in the food and wastewater industries [21; 22; 23].