Sunday, 11 January 2015

What is Carcinogenicity? Carcinogens used in the textile industry…


Carcinogenicity

The term carcinogen denotes a chemical substance or a mixture of chemical substances which induce cancer or increase its incidence. An alternate definition is that carcinogenic substances are ones that "induce tumors (benign or malignant), increase their incidence or malignancy, or shorten the time of tumor occurrence when they are inhaled, injected, dermally applied, or ingested".

Carcinogens are classified according to their mode of action as genotoxic or nongenotoxic carcinogens. Genotoxic carcinogens initiate carcinogenesis by direct interaction with DNA, resulting in DNA damage or chromosomal aberrations that can be detected by genotoxicity tests. Nongenotoxic carcinogens are agents that do not directly interact with DNA and are believed to enhance tumor development by affecting gene expression, signal transduction, and/or cell proliferation. In animal studies, most potent mutagens are also found to be carcinogenic. Substances that induce tumors in animals are considered as presumed or suspected human carcinogens until convincing evidence to the contrary is presented.

Cancer Causing Agents

Arsenic is a naturally occurring element. It is most commonly used as a wood preservative (in pressure treated wood) and can be found in building materials, industry, and water (inorganic) as well as fish and shellfish (organic compounds). Exposure is through inhalation or ingestion (intentional poisoning). Arsenic is linked to lung cancer, skin cancer, and urinary tract cancer. Arsenic is a known human carcinogen. It can also be found in the poorly processed polyester and leather products.
Asbestos is a group of naturally produced chemicals composed of silicon compounds. It is used in textile products due to its short fibers and ability to spun and woven. Its fire proofing capabilities make it used in fire proof products and clothing. It is also used in insulation materials due to heat resistance. Human exposure is through inhalation (from disruption of materials containing asbestos) and ingestion (contaminated food/water). Tiny asbestos fibers in the air can get trapped and accumulate in the lungs. Asbestos is linked to increased risk of lung cancer, and development of mesothelioma (cancer of the thin lining surrounding the lung (pleural membrane) or abdominal cavity (the peritoneum)) and laryngeal cancer. Cancer may appear 30 to 50 years after exposure. Asbestos is a known human carcinogen.
Bisphenol A (BPA), a building block of polycarbonate plastic, is one of the most widely produced chemicals in the world. In the textile industry it is used in the finishing process of woven fabrics usually polyester and other synthetic woven fabrics. It is used in hard plastics, food cans, drink cans, receipts, and dental sealants. BPA is ubiquitous. CDC bio monitoring surveys indicate that more than 90% of Americans have the substance in their bodies. BPA is an endocrine disruptor linked to breast and prostate cancer. The International Agency for Research on Cancer has listed BPA as "not classifiable as to its carcinogenicity in humans."
Chromium Hexavalent compounds. Elemental chromium does not occur naturally; chromium (IV) compounds are highly corrosive and strong oxidizing agents rarely found in nature. Coal-burning power plants are our nation's largest industrial source of chromium (IV). Such compounds are also used as corrosion inhibitors in the leather tanning process, in the manufacture of dyes and pigments, and in wood preserving, chrome plating, and steel and other alloy production. Exposure is through inhalation, ingestion (chromium leached into soil and water), and dermal contact. They are linked to lung, nasal, and nasopharyngeal cancer. Chromium hexavalent compounds are a known human carcinogen.
Dioxins are a group of chemicals formed as unintentional byproducts of industrial processes involving chlorine, such as waste incineration, chemical manufacturing, and pulp and paper bleaching. Dioxins include polychlorinated dibenzo dioxins (PCDDs), polychlorinated dibenzo furans (PCDFs), and the polychlorinated biphenyls (PCBs). Exposure is through the ingestion of contaminated foods and, to a lesser extent, dermal contact. Dioxins accumulate in fat cells and degrade very slowly in the environment.
Formaldehyde can be found in a variety of building and home decoration products (as urea-formaldehyde resins and phenol-formaldehyde resin). It is also used as a preservative and disinfectant. Exposure is through inhalation and dermal contact. Automobile exhaust is the greatest contributor to formaldehyde concentrations in ambient air. Construction materials, furnishings, and cigarettes account for most formaldehyde in indoor air. Formaldehyde has caused nasal cancer in rats after long term exposure; it is linked to leukemia and nasopharyngeal cancer in humans. It is a known human carcinogen.
Polybrominated diphenylethers (PBDEs) are used as flame retardants in furniture, computers, electronics, medical equipment, and mattresses. Exposure is through inhalation, ingestion and dermal contact. Two of the common commercial formulations, penta- and octa-BDE, have been voluntarily phased out of US production. Deca-BDE continues to be produced. Highly persistent in the environment, they are endocrine disruptors. PBDEs are linked to liver cancer in laboratory animals, but are not classifiable as to carcinogenicity in people.
Vinyl Chloride, which is used by plastics companies in the production of PVCs, PVC fibers and copolymers. Exposure is largely occupational, and results from inhalation, ingestion or dermal contact. Exposure is very low in the general population. Exposure to vinyl chloride is linked to the development of liver cancer and weakly associated with brain cancer. Vinyl chloride is a known human carcinogen.

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