Cu2+ and Fe2+ mediated photodegradation studies of soil-incorporated chlorpyrifos

Abstract

The influences of Cu(2+) and Fe(2+) on the photodegradation of soil-incorporated chlorpyrifos were investigated in the present study. The soil samples spiked with chlorpyrifos and selected metal ions were irradiated with UV light for different intervals of time and analyzed by HPLC. The unsterile and sterile control soil samples amended with pesticides and selected metals were incubated in the dark at 25 °C for the same time intervals. The results of the study evidenced that photodegradation of chlorpyrifos followed the first-order kinetics. The dissipation t0.5 of chlorpyrifos was found to decrease from 41 to 20 days under UV irradiation. The rate of chlorpyrifos photodegradation was increased in the presence of both metals, i.e., Cu(2+) and Fe(2+). Thus, initially observed t0.5 of 19.8 days was decreased to 4.39 days in the case of Cu(+2) and 19.25 days for Fe(+2). Copper was found to increase the rate of photodegradation by 4.5 orders of magnitude while the microbial degradation of chlorpyrifos was increased only twofold. The microbial degradation of chlorpyrifos was only negligibly affected by Fe(2+) amendment. The studied trace metals also affected the abiotic degradation of the pesticide in the order Cu(2+) > Fe(2+).

Zn2+ and Cd2+ assisted photo-catalytic degradation of chlorpyrifos in soil

“…1-b]. A Similar relation has already been reported by Rafique et al. (2016a, as well as by Racke et al.…”

“…For example, Zn 2+ and Cu 2+ are known to reduce the dissipation of deltamethrin and cypermethrin in the soil but Fe promotes their dissipation rate (Yang et al., 2010) . Similarly, our previous studies have also reported the degradation of CLP, and a number of other pesticides in the presence of some metals (Rafique et al., 2016a, Rafique and Tariq, 2015). It is important to determine the metals that have pronounced influence on the photodegradation of pesticides but have minimal hazardous effect on the environment so that a strategy may be developed for safer remediation of these pesticides from the soil.…”

“…The repeated use of chlorpyrifos (CLP) for eradication of pests from cotton, wheat and vegetable fields has increased the public concerns on potential human health risks. Several reports indicate the presence of CLP in soil, crops, grains and blood of farmers around the world (Mansour et al., 2009, Rafique et al., 2016a,). Excessive use of fertilizer, organic manure and waste water for irrigation is main source of heavy metals in these soils (Rafique et al., 2016b).…”

Pesticide Pollution in Agricultural Soils and Sustainable Remediation Methods: a Review

“…The major mechanism of those technologies was that the pesticide was removed from the contaminated soil to the flushing fluids through adsorption, desorption, and volatilization. Some chemical remediation technologies, such as enhanced electrokinetic-Fenton [10], advanced oxidation process [86], and photo-degradation [84] were used for pesticide-contaminated soil through special chemical reactions (abiotic degradation). Both physical and Table 1 Current research work on the remediation and efficiency of treatment strategies of pesticide-polluted soils (2015-2017)…”