MAN-MADE CHEMICALS

Those man-made chemicals which have been identified as being oestrogenic belong to several major groups of chemicals including organochlorine pesticides, polychlorinated biphenyls, alkylphenolic compounds, ... 

Axokine is another new drug under development. Axokine is a synthetic (man-made) chemical that mimics a hormone produced in the brain that is responsible for protecting the body from injury. Axokine was initially developed as a treatment for Lou Gehrig s disease, but researchers noticed that... 

Acrylonitrile is a colorless, liquid, man-made chemical with a sharp, onion-or garlic-like odor. Acrylonitrile is used mostly to make plastics, acrylic fibers, and synthetic rubber. Because acrylonitrile evaporates quickly, it is most likely to be found in the air around chemical plants where it is made. Acrylonitrile breaks down quickly in the air. It has been found in small amounts in the water and soil near manufacturing plants and hazardous waste sites. In water, acrylonitrile usually breaks down in about 1 to 2 weeks, although this can vary depending on conditions. For example, high concentrations of acrylonitrile (such as might occur after a spill) tend to be broken down more slowly. In one case, measurable amounts of acrylonitrile were found in nearby wells 1 year after a spill. Further information on the properties and uses of acrylonitrile and how it behaves in the environment may be found in Chapters 3, 4, and 5. 

Furthermore, following concerns over the way the ozone layer is being damaged by man-made chemicals, some UV-c now reaches the Earth s surface, particularly in Australasia and some parts of South America. People living in such places are not adequately protected against the harmful effects of the sun s rays by the melanin in their skin. 

It is briefly reported that flame retardants were among the chemicals discovered in the blood of Margot Wallstrom, European Commissioner for the Environment. Wallstrom submitted a sample for testing to illustrate the presence of persistent chemicals in the human body. The Department of Environmental Sciences at Lancaster University tested for the presence of 77 man-made chemicals. The laboratory discovered 28 chemicals in Wallstrom s blood, including polybrominated diphenyl ethers, commonly used as flame retardants. 

Phenol is both a man-made chemical and produced naturally. It is found in nature in some foods and in human and animal wastes and decomposing organic material. The largest single use of phenol is as an intermediate in the production of phenolic resins. However, it is also used in the production of caprolactam (which is used in the manufacture of nylon 6 and other synthetic fibers) and bisphenol A (which is used in the manufacture of epoxy and other resins). Phenol is also used as a slimicide (a chemical toxic to bacteria and fungi characteristic of aqueous slimes), as a disinfectant, and in medicinal preparations such as over-the-counter treatments for sore throats. Phenol ranks in the top 50 in production volumes for chemicals produced in the United States. Chapters 3 and 4 contain more information. 

Steen, W.C. Microbial transformation rate constants of structurally diverse man-made chemicals. Environmental Research Laboratory, Athens, GA., U.S. EPA Report-600/S93-91/016, 1991, 2 p. 

At issue is a group of man-made chemicals called chlorofluorocarbons (CFCs), which are used as the refrigeration fluids (Freon) in the air-conditioning and refrigeration units of automobiles, homes, and industry and which, in the past, were used as the pressure gas in spray cans of paint, deodorants, and so forth. There are a number of compounds containing... 

The industrial revolution brought many advances in technology it also brought increased problems with pollution and environmental toxins. Humans now live in an environment that is rich in man-made chemicals. Currently, there are more than 65,000 chemicals in common use with approximately 400 new chemicals entering the environment on a yearly basis. Not surprisingly, toxicology may assume a role of increasing importance within the realm of human health. 

The process of redesigning the European Union s Chemical Policy was triggered by several factors. A large number of man-made chemicals has been released into the environment, is still being and will inevitably be released in the near future. There are several cases of chemicals which had been considered to be safe but which due to their persistent nature manifested environmental harm in areas outside of their initial assessment. 

What sort of chemistry controls the formation of an ozone layer What effects might man-made chemicals have on the ozone layer These... 

In the following discussions we first look at hydrolytic reactions of ester functions. As already mentioned in Chapter 2, ester functions are among the most common acid derivatives present in natural as well as man-made chemicals (e.g., lipids, plasticizers, pesticides). In a general way, an ester bond is defined as ... 

The air-water interface plays a key role among all natural boundaries. It controls the global distribution of many important natural and man-made chemicals (C02, CH4,... 

Along these lines, other test systems in combination with concentration methods were developed and applied. Although most chemicals have been introduced into the environment in ways that did not result in immediate effects on the environment, the total load of chemical pollutants has certainly contributed to observed changes in the structure and function of aquatic ecosystems. We now rely on aquatic toxicology to give reliable and proper information on the possible effects of man-made chemicals. This information enables the protection of aquatic ecosystems and, in particular, provides for the required scientific guidance in legislation and enforcement. 

Water with relatively insignificant amounts of man-made chemicals but having appreciable TOC levels that yield mutagens as chlorination byproducts. These mutagenic mix-tines generally do not require metabolic activation but rather are less active when assayed +S9. 

OC are man-made chemical substances that encompass a wide range of compounds with different structures and applications. They are known for their high chemical stability, which stems from their large proportion of halogen substituents, either chlorine, bromine or others. Some of them were synthesised for use as pesticides and others for industrial applications. 

Bis(chloromethyl) ether (BCME) is a man-made chemical with a strong, unpleasant odor. It is a clear liquid at room temperature, but it readily evaporates into air. BCME undergoes chemical reactions easily, so it is broken down very rapidly when it comes into contact with water. Consequently, any BCME that might escape from a chemical plant or a chemical waste site into water or moist soil would be destroyed within a few minutes. BCME that escapes into air is also broken down by reacting with water and other chemicals, but this takes a few hours. 

About ten years ago when people were told there were 70.000 man-made chemicals in use globally, they reared back in their seats in amazement. Five years ago that number jumped to 87,000, and today the figure is over 100,000. Of those 100,000, 5,200 are produced in quantities of over 2 million pounds a year, and one chemical was produced in quantities of oven.2 billion pounds in one year in the United States alone. Not one of these 100,000 chemicals was thoroughly tested for what it might do to a baby before it is born. 

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