Persistent organic pollutants are highly toxic synthetic organic (carbon-based) chemicals. These chemicals are fairly recent in their existence Â– it is only since the industrial boom following World War II that they have been produced on a large scale, Most are produced intentionally as commercial products, particularly pesticides. The most harmful pesticides include aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, and toxaphene, furthur they are also produced for use in industrial processes, such as coolants for electrical transformers. This group includes polychlorinated biphenyls (PCBs) and hexachlorobenzene,The third category encompasses POPs that are produced unintentionally in industrial processes, as the by-products of the manufacture, use, or combustion of chlorine and chlorine-containing materials. This group includes dioxins and furan.
Scientific journal is a periodical publication intended to further progress of science, usually by reporting novel research. There are thousands of scientific journals in publication, and many more have been published at various points in the past. Most journals are highly specialized, although some of the oldest journals publish articles and scientific papers across a wide range of scientific fields. Scientific journals contain articles that are peer reviewed, to ensure that articles meet the journal's standards of quality, and scientific validity. The publication of the results of research is an essential part of the scientific method. If they are describing experiments or calculations, they must supply enough details that an independent researcher could repeat the experiment or calculation to verify the results. Each such journal article becomes part of the permanent scientific record.
Last date updated on July, 2014