Xenobiotic compounds pesticides

Many xenobiotic compounds, such as pesticides, are esters, amides, or organophosphate esters, and hydrolysis is a very important aspect of their metabolic fates. Hydrolysis involves the addition of H20 to a molecule accompanied by cleavage of the molecule into two species. The two most common types of compounds that undergo hydrolysis are esters... 

GC-MS has many applications beyond drug screening. Numerous xenobiotic compounds can be readily analyzed by GC-MS. Apphcations for anabolic steroids, pesticides, pollutants, and inborn errors of metabolism have been described. ... 

Most wastewater streams contain significant amounts of carcinogenic, toxic, mutagenic, or genotoxic substances in addition to conventional pollutants. These harmful compounds originate from industrial processes and households. Some of these toxic chemicals may also exhibit endocrine-disrupting effects. Therefore, organic micropollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), nonylphenol, xenobiotics, dioxins, pesticides, and heavy metals create important environmental health risks [3-7]. 

It has been shown in this chapter that the DNA-modified electrodes (electrochemical DNA biosensors) already represent very effective and, at the same time, simple, fast, inexpensive, miniaturized, and mass-producible analytical devices for evaluation and classification of modes of genotoxic effects of individual xenobiotic compounds (e.g., chemical carcinogens, pesticides, dmgs, dyes, or reactive radical species), as well as for prescreening of new drugs and newly synthesized chemicals. Moreover, the evaluation of DNA protection capacity of various natural and synthetic chemical substances (antioxidants) is also possible using the detection of DNA damage caused by prooxidants. 

Historically, organic environmental pollutants were hydrophobic, often persistent, neutral compounds. As a consequence, these substances were readily sorbed by particles and soluble in lipids. In modern times, efforts have been made to make xenobiotics more hydrophilic - often by including ionisable substituents. Presumably, these functional groups would render the compound less bioaccumulative. In particular, many pesticides and pharmaceuticals contain acidic or basic functions. However, studies on the fate and effect of organic environmental pollutants focus mainly on the neutral species [1], In the past, uptake into cells and sorption to biological membranes were often assumed to be only dependent on the neutral species. More recent studies that are reviewed in this chapter show that the ionic organic species play a role both for toxic effects and sorption of compounds to membranes. 

In aquatic environments, reactions are, in many situations, driven by DOC and their interactions with natural compounds and xenobiotics. The more intensive use of spectroscopic tools could help in making headway toward understanding the fate of metals, pesticides, and other xenobiotics in the environment. 

From these inventories and data, it is clear that society is facing an enormous problem of contamination. Many of the polluting compounds that are continuously dispersed are products of industrial activities such as phenols and halogenated phenols, polycyclic aromatic hydrocarbons (PAH s), endocrine disruptive chemicals (EDC), pesticides, dioxins, polychlorinated biphenyls (PCB s), industrial dyes, and other xenobiotics. In this chapter, we critically review the literature information on the enzymatic transformation of these polluting xenobiotics. This work is focused on peroxidases as enzymes able to transform a variety of pollutant compounds with the aim to reduce their toxicity and their environmental impact. 

In addition, a number of natural elements and molecules have been combined through human inventiveness into synthetic compounds that are particularly beneficial to mankind and its present quality of life, many of which are xenobiotic substances (i.e., substances not found in nature). Some of these substances have been introduced into the environment deliberately, like pesticides others have been discharged into the environment either by accident or as wastes, owing in part to the lack of awareness of the possible negative environmental and human impact in the long, or even the short, term or of the dispersion and transformations that such compounds may undergo. This is known as the Law of Ignored or Unexpected Consequences. 

Xenobiotic organic compounds (XOCs) originating from household or industrial chemicals and present in relatively low concentrations in the leachate (usually less than ImgL of individual compounds). These compounds include, among others, a variety of aromatic hydrocarbons, phenols, chlorinated aliphatic hydrocarbons, and pesticides. 

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