Lipophiles water pollution

Water pollution causes the introduction of a very wide variety of toxic chemicals to those drinking, cooking, and bathing with impure water. There are numerous sources of pollutants that end up in potable water, and the mixtures produced by many of these pollutants result in unexpected toxic effects in people who consume such water. Mixtures of lipophilic and hydrophilic chemicals have been demonstrated to be causative for many of these unanticipated toxic effects. 

For analyzing water pollution it is necessary to know the area where the sample(s) were harvested. Among the primary water pollutants are pesticides, since they are slowly degraded and require dissemination. The chlorinated pesticides are lipophilic and are slowly accumulated in animals. The effect is due to metabolic system perturbation. Other water pollution sources are heavy metals, which are determined by the highly sensitive and selective analytical method ICP-AES.29 The sampling process, in this case, consists of chromatographic separation techniques for pesticide separation.30... 

After uptake, lipophilic pollutants tend to move into hydrophobic domains within animals or plants (membranes, lipoproteins, depot fat, etc.), unless they are biotransformed into more polar and water soluble with compounds having low Metabolism of lipophilic compounds proceeds in two stages ... 

In phase 1, the pollutant is converted into a more water-soluble metabolites, by oxidation, hydrolysis, hydration, or reduction. Usually, phase 1 metabolism introduces one or more hydroxyl groups. In phase 2, a water-soluble endogenous species (usually an anion) is attached to the metabolite— very commonly through a hydroxyl group introduced during phase 1. Although this scheme describes the course of most biotransformations of lipophilic xenobiotics, there can be departures from it. 

Ahel M, McEvoy J, Giger W (1993) Bioaccumulation of the lipophilic metabolites of nonionic surfactants in fresh-water organisms. Environ Pollut 79 243-248... 

The vertical distribution of pollutants originates from water movements and sinking of organic particulate matter operating as carriers for lipophilic substances. PFOA enters ocean water exclusively in the surface level and instantaneously establishes... 

For the purpose of the following discussion, the xenobiotics studied in the dogfish shark were divided into three classes 1) those relatively hydrophilic (Table V) those relatively lipophilic (i.e., solubility in water less than 1 mg/ml, Table VI) and, 3) metal-containing pollutants (Table VII) Most of these data have been previously reported (18-23) using C compound, for assay, with the exception of sodium lauryl sulfate (SLS) ( S), cis-Pt (atomic absorption spectroscopy) and phenol red (spectrophotometry). Unless otherwise stated these data are presented as total radioactivity and the hazards of doing so are recognized (24). 

Chlorinated micropoUutants are harmful for man and environment due to their toxicity, persistence, and bioaccumulation. Persistent compounds are very stable and difficult to get metabolized and mineralized by biological and chemical processes in the environment, and as a result, they have become ubiquitous in water, sediments, and the atmosphere bioaccumulation is the result of the lipophilicity of these compounds. Polychlorinated dibenzodioxins and -furans (PCDD/F) are not produced purposely like many of other chlorinated technical products, such as chlorinated biocides DDT, lindane, and toxaphene. The production and use of persistent organic pollutants (POPs), the dirty dozen has now been banned worldwide by the Stockholm protocol. It should be mentioned that about 3000 halogenated products have now been isolated as natural products in plants, microorganisms, and animals," but the total amount of these products is much smaller compared to xenobiotics. 

The hydrophobicity of an organic molecule is quantified by means of its partition coefficient between octanol and water (Kow)- Kow is equal to the ratio of compound concentrations at saturation in n-octanol and in water at equilibrium and at a specific temperature. n-Octanol possesses structural properties analogous to lipidic tissues of organisms, and so Kow allows evaluation of the lipophilic character of the contaminant and thus of its capacity to be accumulated in the lipidic tissues of living organisms. The Kow value of hydrophobic organic pollutants (HOPs) is higher than 100. They are nonpolar molecules with a low water solubility. Their weak solubility and their hydrophobicity... 

Some pollutants are assimilated by oiganisms to a greater extent than others, and, if they are lipophilic, they may accumulate. Measures of exposure to chemicals which bioaccumulate in tissue are easily accomplished through an analysis of tissue residues. In the absence of tissue residues, empirical constants are often derived and used by ecotoxicologists to predict bioaccumulation examples include the octanol—water partition coefficient, which approximates a chemical s behavior between the lipid and water phase (see Section 8.3), the bioconcentration factor (BFC), and the bioaccumulation factor (BAC). These last two are defined as follows ... 

Soil contamination can contribute to human toxic exposure via a number of routes. These include plant uptakes of soil pollutants, including fertilizers and pesticides, that are either eaten by people directly or passed up the food chain, absorption onto the skin and subsequently into the bodies of grazing animals to be passed up through the food chain by animals, and via contaminated airborne soil particles that are ultimately inhaled by humans. Soils contain large lipophilic components that absorb lipophilic chemicals which are subsequently transferred to plants, animals, and to the air. Water distributed in soil dissolves hydrophilic chemicals and acts as a conduit for ultimate human absorption, through plants and thus up the food chain from whence they ultimately impact humans. 

The sources of lipophilic/hydrophilic chemical exposure include environmental pollution (air, water, and soil contamination), pesticide, herbicide, and fertilizer residues in foods and drinking water, excipients (non-active additives such as colors, flavors, rheological agents, etc,) in foods and pharmaceuticals, industrial chemicals, household chemical products, personal care products, cosmetics, and environmentally synthesized chemicals that are formed from reactions with released chemicals with each other and with naturally present species. 

Biological processes in nature can also create the opposite effect—formation of more stable, less degradable compounds. Phenols are biomethylated in the environment to their corresponding anisoles which are more stable and lipophilic. This means that phenol pollution studies must also take into account formation and bioaccumulation of anisoles. Biomethylation of phenols to more bioaccumulating anisoles has not only environmental, but also economic consequences, as chloroanisoles are extremely bad-tasting compounds. For example, in sensory panel studies of water solutions, the concentration fimit of detectable odor was lowered 3 to 10 orders of magnitude during anisole formation in... 

Interest In the phylogenetic aspects of xenobiotic metabolizing enzymes has motivated several Investigators to study xenobiotic conjugation In aquatic animals. In addition, evidence of extensive chemical pollution of some bodies of water which results In the exposure of aquatic animals to xenobiotics has provided a practical reason to study the ability of aquatic animals to biotransform lipophilic foreign chemicals to more polar metabolites which should be more readily excreted. 

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