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Multiarray Biosensors for Toxicity Monitoring
Published in George K. Knopf, Amarjeet S. Bassi, Smart Biosensor Technology, 2018
Omowunmi A. Sadik, Silvana Andreescu, Jason Karasinski
The principle of a gas sensor is based on changes in the electrical resistance when a volatile chemical is absorbed onto its surface. This change in electrical resistance is characteristic to each analyte and can be monitored and used to create a distinct pattern. The samples are collected using a sample collector system, equilibrated, and exposed to the sensor array under controlled temperature, pH, and pressure. In addition to the analyte samples, reference air samples are passed thought the sensor array to produce a baseline signal. Finally, the changes in resistance versus time are monitored and recorded on each channel. We have recently used this technology for the detection and classification of organophosphate nerve agents: paraoxon, parathion, malathion, dichlorvos, trichlorfon, and diazinon (4). In this application, an array of 32 conducting polymer sensors was used as a detector for an AS32/8S commercial gas-sensing Labstation. The sensor array was fabricated electrochemically by electrodeposition of polypyrrole onto a metallic substrate. The deposition was carried out by cyclic voltammetry using a three-electrode system in which the metallic substrate was the working electrode. The sensor responses are analyzed using ANN and compared with a new type of classifier, namely support vector machines (SVMs).
Toxicity of pesticides
Published in Chris Winder, Neill Stacey, Occupational Toxicology, 2004
Some organophosphorus insecticides (that is, chlorpyrifos, dichlorvos, methamidophos, trichlorfon and trichlornat, isofenphos) caused a sensorimotor polyneuropathy known as organophosphate-induced delayed polyneuropathy (OPIDP) (Lotti 1992; Moretto and Lotti 1998; Tracey and Gallagher 1990). Most cases of OPIDP were suicidal, and only a few involved careless occupational exposures to methamidophos. OPIDP is characterised by flaccid paralysis of the lower limbs but the upper limbs might also be affected in severe cases. Sensory peripheral nervous system is affected to a lesser degree (Moretto and Lotti 1998). Histopathology shows degeneration of long and large-diameter axons in peripheral nerves and spinal cord. OPIDP development is unrelated to inhibition of AChE and the putative molecular target is a nervous system protein called neuropathy target esterase (NTE) (Lotti 1992). Since all commercial organophosphorus insecticides display a high potency for acetylcholinesterase, OPIDP always developed after doses causing severe cholinergic syndrome.
Organophosphorus Compounds as Pesticides and Their Detection Using Nanomaterials
Published in Bhupinder Singh, Om Prakash Katare, Eliana B. Souto, NanoAgroceuticals & NanoPhytoChemicals, 2018
Divya Utreja, P. Sharma, S. Singh, M. Kaur
Trichlorfon (15) is a broad-spectrum insecticide of low mammalian toxicity, and it is effective as a stomach and contact insecticide. It is used as a foliar spray against lepidopterous larvae and finds use in the dairy barn as bait for fly control. Trichlorfon (15) is converted readily to dichlorvos, a conversion believed responsible for much of its activity. The LD50 for rats is 630 mg/kg.
Phytoremediation of cadmium-trichlorfon co-contaminated water by Indian mustard (Brassica juncea): growth and physiological responses
Published in International Journal of Phytoremediation, 2023
Chao Zhang, Feng He, Lanzhou Chen
Cadmium (Cd) has attracted increasing attention due to its strong toxicity at even low concentrations (Valderrama et al. 2012). Cd stress can affect the growth and physiological characteristics of plants, such as causing leaf chlorosis and withering, inhibiting biomass and root elongation, and altering metabolic processes and nutrient uptake and distribution (Wang et al. 2008; Gomes et al. 2012). Moreover, Cd also causes severe threats to human health through the food chain (Adhikari et al. 2018). Trichlorfon (TCF) is a widely used organophosphorus insecticide and used as an agricultural pesticide to control pests on crops, a human medicine to combat internal parasites, and an ectoparasiticide in livestock and aquaculture (Li et al. 2011; Chang et al. 2013). However, the long-term widespread use and overuse of trichlorfon pose risks to public and environmental health, for example, causing histopathological injury (Mataqueiro et al. 2009), the toxic effect on hepatocytes (Woo et al. 2018) and immune system (Baldissera et al. 2018), and other biochemical effects (Woo et al. 2018) of animals and even humans. Therefore, conducting remediation research on Cd and TCF combined pollution is of great significance for protecting the agricultural ecological environment.
Physiological response and removal ability of freshwater diatom Nitzschia palea to two organophosphorus pesticides
Published in Chemistry and Ecology, 2020
Yuhang Wang, Weijie Mu, Xiaoli Sun, Xinxin Lu, Yawen Fan, Yan Liu
Organophosphorus pesticides (OPs) are a class of organic chemicals containing phosphorus, which frequently and largely applied throughout the world in agriculture, industry and Public Health due to their biodegradable nature [1]. However, the unreasonable and indiscriminately application of pesticides led to their recurring emerge in water ecosystem [2]. Acephate and trichlorfon are low venomous insecticides and have aroused highly concern on account of its intermediate products, which are more poisonous than other pesticides and its precursor [3]. Acephate [4,5ACP, O, S-dimethyl acetylphosphoramidothioate is a broad-spectrum insecticide, with a half-life of 50 days, degrading to the more toxic methamidophos easily (20°C and pH 7.0) ]. However, the mobility of acephate in soil is slightly faster than that of methamidophos and acephate may lead to the contamination of groundwater much more easily than methamidophos under normal conditions [6]. Trichlorfon [7TCF, dimethyl-(2,2,2-trichloro-1-hydroxyethyl) phosphate is a typically used broad-spectrum organophosphate insecticide produced increasingly at a large scale because of its controlling on a variety of arthropod pests ]. Despite trichlorfon has a short half-time life in the water (approximately 57 h) [8], it can easily be degraded to the highly toxic insecticide dichlorvos [9]. The recommended dosage of trichlorfon is 300 mg L−1 at temperatures below 6°C and 15 mg L−1 between 14°C and 18°C; however, the trichlorfon is often abused by farmers [10]. ACP and TCF be used for long term in agriculture and veterinary leading to accumulation in soil [11]. Organophosphorus pesticides diffuse to water to inhibit arthropods growth through inadvertent overflow or spraying, which contribute to water pollution [12]. The fomite of the water ecosystem with OPs may affect non-target organisms [13]. Kumar et al. found ACP inhibited the growth of Chlamydomonas mexicana seriously at the concentration of 25 mg L−1 [14]. Chen and Jiang found that TCF influenced cell growth in Dunaliella salina due to trichlorfon exposure [15]. In fact, it has been found that different microalgae species have various responses to the same pollution [15,16], and studies on pollutant response of species will provide effective information for biological monitoring. Toxicity of ACP and TCF and their impact on diatom had been not assessed.