Experimental Investigation Of The Toxicity And The Chemical Oxidation Removal Of Chlorpyfifos

Organophosphate(OP) pesticides have played an important role in agriculture to control the major insect pests, chlorpyrifos(CPF), i.e. O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate being one of the effective common. CPF has been widely used throughout the world to control the insect pests of crops, fruit, vegetable and ornamental plants, as well as to control flies, mosquitoes and household pests. The excessive use of CPF results in the widespread existence in environments. A major pathway for unintentional introduction of CPF into aquatic ecosystems is surface runoff from fields treated by this kind of OP. CPF can impact a non-target toxicity to aquatic organisms and mammals. CPF was reported that CPF poses a much more danger to children than adults. CPF can induce the formation of reactive oxygen species, and thereby, increasing genomic instability and contributing to the initiation as well as the progression of cancer. Furthermore, CPF has exhibited hepatotoxicity, nephrotoxicity, and immunological abnormalities.The aim of this study is to extend the application of electrochemical and ultraviolet spectrum techniques for evaluating the toxicities of pollutants, and to shed light on some aspects of the molecular mechanism of potential toxicity of CPF. In this research, cyclic voltammetry(CV), anodic differential pulse voltammetry(ADPV), electrochemical impedance spectroscopy(EIS) and ultraviolet spectrum were used to illustrate the interactions of CPF with guanine, adenine, thymine, cytosine and xanthine. The DFT reactivity descriptors chemical potential(μ), electronegativity(χ) and electrophilicity index(ω) were considered to explore the chemical reactivity of CPF, guanine, adenine, thymine, cytosine and xanthine. The local reactivity index of condensed FF(fk+ for electrophilic attack, and fk- for nucleophilic attack) was also calculated to reveal the reactive sites of the six molecules. Furthermore, the contributions of charge transfer(ΔN) to the reactivity of CPF with the DNA bases at 298 K were calculated. To some extent, we believe that this work will be of benefit for the conception of an interaction model of biomolecule with this organophosphate pesticide which would be valuable for further studies on the genotoxicity of OPs.In this research, the chemical Fenton oxidation process was employed to degrade CPF. Fenton oxidation process, as an advanced oxidation technology, has the advantages of high efficiency and cost-efficitive. The effects of parameters including p H, and the dosaged contrations of hydrogen peroxide, metal cations and organic acids on the chemical oxidation degradation of CPF were evaluated. Under the condition of different p Hs, the degradation rates of CPF is different. In additional, the additions of metal cations and organic acids can affect the degradation of chlorpyrifos. The coexistent Cu2+ and Co2+ can promote the degradation of CPF and the presence of succinic acid and oxalic acid also accelerate the oxidation removal of CPF. On the contrary, citric acid and nitilotriacetic acid showed the negative effect in the degradation of CPF.