Environment naturally occurring chemicals

Chemicals are ubiquitous as air, carbohydrates, enzymes, lipids, minerals, proteins, vitamins, water, and wood. Naturally occurring chemicals are supplemented by man-made substances. There are about 70000 chemicals in use with another 500-1000 added each year. Their properties have been harnessed to enhance the quality of life, e.g. cosmetics, detergents, energy fuels, explosives, fertilizers, foods and drinks, glass, metals, paints, paper, pesticides, pharmaceuticals, plastics, rubber, solvents, textiles thus chemicals are found in virtually all workplaces. Besides the benefits, chemicals also pose dangers to man and the environment. For example ... 

The solubility of most metals is much higher when they exist as organometallic complexes.4445 Naturally occurring chemicals that can partially complex with metal compounds and increase the solubility of the metal include aliphatic acids, aromatic acids, alcohols, aldehydes, ketones, amines, aromatic hydrocarbons, esters, ethers, and phenols. Several complexation processes, including chelation and hydration, can occur in the deep-well environment. 

A specialty of geology concerned with earth processes, earth resources, and engineering properties of earth materials and relevant to (1) the protection of human health and natural ecosystems from adverse biochemical and/or geochemical reactions to naturally occurring chemicals or to chemical compounds released into the environment by human activities and (2) the protection of life, safety, and well-being of humans from natural processes, such as floods, hurricanes, earthquakes and landslides, through land-use planning. 

Organization formed to promote the understanding of interactions between organisms and their environment that are mediated by naturally occurring chemicals. do Dr. Stephen Foster, Dept, of Entomology,... 

Sixty to eighty percent of all human cancers are associated with our environment and environmental agents. The environment is a complex mixture of chemicals that originate from industrial and technological development and, most importantly, natural sources. Many industrial chemicals, pesticides, insecticides and food additives have exhibited carcinogenic properties in various animal model systems, and occupational and drug exposure has led to human cancers. However, estimates attribute the majority of human cancers associated with the environment not to intentional or accidental chemical exposure, but to the vast number of naturally occurring chemicals in our environment (Doll and Peto, 1981). 

To understand chemical reactions and chemical transfer between phases, knowledge of the various types of chemicals that occur in the environment is necessary. Furthermore, understanding some of the bonds that occur within chemicals is useful because many of the properties of a chemical arise from the nature of the bonds that hold it together. Chemicals foimd in the environment include not only pollutants but also the myriad of naturally occurring chemicals that shape the entire face of the natural world. 

Reductive reactions typically occur in anaerobic environments where there is an abundant supply of electron donors. Electron donors are typically of microbial origin, eg, porphyrins or cysteine, which sometimes leads to confusion regarding the nature, ie, chemical vs enzymatic, of the reductive reaction. By definition, all reductive reactions which are not enzymatically catalyzed are chemical. The most significant chemical reductive reaction is reductive dechlorination. 

The environment has negative effects on most metals thus, when metallic archaeological objects are eventually found, they are generally in an advanced state of decay. The decay of metals and alloys caused by the chemical action of gases and/or liquids in the environment is known as corrosion. Corrosion processes are natural destructive processes that result in the waste of most metals and alloys. The ultimate result of all corrosion processes is the reversion of most metals from the metallic condition in which they are used, to the chemically combined form in which they naturally occur in the crust of the earth. Rust, the reddish-brown corrosion product that forms on... 

Chapter 4 discusses chemical and physical transformations of matter, both those that occur naturally in the environment and in living organisms and those that are invented by chemical scientists. The study of transformations spans the range from efforts to gain a fundamental understanding of naturally occurring... 

There is compelling evidence for the existence of methyltins in the environment, but it is not certain that methylation of naturally occurring inorganic tin compounds account for their presence. However, various biological or chemical processes have been described under laboratory conditions in which methyltin products have been formed from inorganic tin starting materials70. 

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