Photolysis-Induced Neurotoxicity Enhancement of Chlorpyrifos in Aquatic System: A Case Investigation on Caenorhabditis elegans

Abstract

Contamination of the environment by toxic pesticides has become of great concern in agricultural countries. Chlorpyrifos (CP) is among the pesticides most commonly detected in the environment owing to its wide agricultural applications. The aim of this study was to compare potential changes in the toxicity of CP after irradiation. To this end, photolysis of CP was conducted under simulated sunlight, and neurotoxicity assessment was carried out at CP of 20 and 50 μg L–1 and its corresponding irradiated mixture solutions which contain a mixture of identified intermediates using the nematode, Caenorhabditis elegans as a model organism. Photodegradation of 20 μg L–1 CP for 1 h produced no obvious reduction of physiological damage, and more serious effects on animal movement were detected after exposure of the animals to a solution of 50 μg L–1 for 1 h irradiation compared with unirradiated solution. GABAergic and cholinergic neurons were selectively vulnerable to CP exposure, and maximal neuropathological alterations were observed after 1 h irradiation of the CP solutions in coherence with the behavioral impairment. The generation of photoproducts was considered to be responsible for the enhanced disturbance on those biological processes. This work provided useful information on the toxicological assessments of chemicals that were produced during the environmental transformation of pesticides.

Quantification of insecticide spatial distribution within individual citrus trees and efficacy through Asian citrus psyllid reductions under different application methods

“…High‐management commercial citrus groves cannot use fitted knapsack sprayers, which may offer a more targeted application to individual trees in smaller farms or research facilities 30 . In addition, recommended rotations of insecticide types to prevent ACP insecticide resistance development and meet EPA regulations inhibit high‐management groves from repeated applications of the same insecticide within a week of the previous application 44–46 . Therefore, suggestions to increase application frequency or concentration do not offer realistic options for some of the large citrus producers.…”

“…30 In addition, recommended rotations of insecticide types to prevent ACP insecticide resistance development and meet EPA regulations inhibit high-management groves from repeated applications of the same insecticide within a week of the previous application. [44][45][46] Therefore, suggestions to increase application frequency or concentration do not offer realistic options for some of the large citrus producers. In addition, laboratory studies show a 94-100% mortality rate of ACP with direct spray of imidacloprid, even though the same percent reductions are not generated in the field.…”

Caenorhabditis Elegans as a Model for the Study of the Toxicity of Organophosphate Insecticides- A Minireview

“…Further, at sub lethal doses of toxicological equivalence, monocrotophos was found to cause stronger inhibition of AChE [28] than acephate. 14 Products of photolysis of chlorpyrifos induced by 1h-exposure to simulated sunlight have been reported to exert more toxicity to cholinergic and GABAeric neurons in C. elegans as compared to the effect of unexposed chlorpyrifos [29]. 15 AChE-inhibition dependence was studied on inhibition of pharyngeal pumping in C. elegans, in addition to the effect of AChE an activating oxime on above said parameters.…”

Ecotoxicological characterization of micropollutants and wastewater samples from conventional biological and advanced wastewater treatment

“…In addition to these challenges, most pollutants do not fully mineralize during different wastewater treatments, triggering the emission of unknown TPs. TPs may show higher toxicity than their parental compound (Boxall et al 2004, Cao et al 2020b, Cwiertny et al 2014, Knoop et al 2018, Larcher et al 2012, Ma et al 2019, Schlüter-Vorberg et al 2015. The overall situation has thus initiated numerous research projects on the detection and characterization of wastewater-borne (micro)pollutants/TPs (1.2.1) and has strongly challenged WWTP to further reduce emissions such as by technical upgrades (1.2.2).…”

“…2.2) Neurotoxicology and behavioral biology (e.g., Aitlhadj and Stürzenbaum 2013, Avila et al 2011, Bargmann 2006, Cao et al 2020b, Gerhardt et al 2002, Jones and Candido 1999, Ju et al 2014, Leung et al 2008, Liu et al 2019, Matsuura et al 2013, Roh and Choi 2011, Tejeda-Benitez and Olivero-Verbel 2016a, Tseng et al 2013). elegans more research is also needed to correlate these results to other species beholding (more) complex immune systems.…”