Elimination of toxic materials

The kidney is an important organ for the excretion of toxic materials and their metaboHtes, and measurement of these substances in urine may provide a convenient basis for monitoring the exposure of an individual to the parent compound in his or her immediate environment. The Hver has as one of its functions the metaboHsm of foreign compounds some pathways result in detoxification and others in metaboHc activation. Also, the Hver may serve as a route of elimination of toxic materials by excretion in bile. In addition to the Hver (bile) and kidney (urine) as routes of excretion, the lung may act as a route of elimination for volatile compounds. The excretion of materials in sweat, hair, and nails is usually insignificant. 

A consequence of this hindrance to elimination of toxic materials by complex organisms was the development of specialized routes of elimination. These routes generally evolved in concert (i.e., co-evolved) with biotransformation processes that render chemicals amenable to these modes of elimination (see Chapters 7-9). 

Doring FR, Doring N (inventors). (1997). Method and device for the elimination of toxic materials from, in particular, top soil. US Patent 5,595,644. P + P Geotechnik GmbH, assignee. 

It is now recognized that Haber s law does not apply for long exposures to low concentrations. Apparently, there are metabolic processes in the human body (and in animals) that can (for many toxic materials) result in biotransiormation or detoxification, elimination, or excretion of toxic materials, or can repair damaged cells or tissues (Elkins, The Chemistry of Industrial Toxicology, 2d ed., p. 242,1959 U.S. Federal... 

Invasion of the tissues by an infective agent initiates an inflammatory response in the animal. This is non-specific and is mediated primarily by substances released from tissues that are damaged as a result of either trauma or the toxic effects of the infective agent. The major mediator is the vasoactive amine histamine, which causes an increased local blood flow and capillary permeability, resulting in local oedema. A major aspect of the inflammatory response is the involvement of large numbers of phagocytic cells, particularly the polymorphonuclear leucocytes. These are chemotactically attracted to the inflamed tissues and are mainly responsible for the elimination of particulate material. This often results in the destruction of many of these cells and the formation of pus. 

Barriers to the Environment. Through evolution, increased complexity of organisms led to increased exploitation of various environments. In order to survive in these environments, organisms developed barriers such as skin and scales that protect from harsh conditions on the outside and minimize loss of vital constituents such as water on the inside. Likewise these barriers impede the elimination of toxic constituents by the organisms, requiring the development of specialized membranes and organs through which toxic materials can be eliminated. 

Elimination of toxic reagents and intermediates [via novel catalysis] ...Anhydrous hydrofluoric and fuming sulfuric acids are used as catalysts throughout the chemical and petroleum industry. Replacing these materials with safe, solid catalysts could have a profound positive impact on industry. 

Clean Production Action promotes the use of products that are safer and cleaner across their life cycle for consumers, workers, and communities. Our mission is to advance clean production, which we define as the design of products and manufacturing processes in harmony with natural ecological cycles, the elimination of toxic waste and inputs, and the use of renewable energy and materials. 

DOE 0 450.1, CRD sec. 9 EO 13101, sec. 401 4.5.1 In developing plans, drawings, work statements, specifications, or other product descriptions, contractors shall consider, as appropriate, a broad range of factors including elimination of virgin material requirements use of biobased products use of recovered materials reuse of product life-cycle cost recyclability use of environmentally preferable products waste prevention (including toxicity reduction or elimination) and ultimate disposal. ... 

Numerous studies are underway to find surface treatment methods that minimize or eliminate use of toxic materials or polluting substances. Some progress is being made, " but replacement of such degreasing solvents as trichloroethane and such toxic materials as the dichromates will take time. For polymeric surfaces, plasma or corona discharge treatments are receiving much attention. 

DMC low toxicity and low environmental impact elimination of toxic and polluting chloride materials creation of not-dangerous and not- polluting products technology and market leadership... 

It is important to appreciate that the magnitude of the absorbed dose, the relative amounts of bio transformation product, and the distribution and elimination of metaboUtes and parent compound seen with a single exposure, may be modified by repeated exposures. For example, repeated exposure may enhance mechanisms responsible for biotransformation of the absorbed material, and thus modify the relative proportions of the metaboUtes and parent molecule, and thus the retention pattern of these materials. Clearly, this could influence the likelihood for target organ toxicity. Additionally, and particularly when there is a slow excretion rate, repeated exposures may increase the possibiUty for progressive loading of tissues and body fluids, and hence the potential for cumulative toxicity. 

Health and Safety Factors. The Material Safety Data Sheets provided by the suppUers should be consulted for each product. In general, products are aqueous emulsions with low levels of toxicity. Products with high solvent content have mostly been eliminated. Personnel handling the chemicals should always avoid contact of the products with skin and eyes, and avoid exposure to vapors if the product contains volatile components. 

Oxidation and reduction reactions can be carried out usiag reformer hydrogen and oxygen from the air. To decide when electroorganic synthesis is likely to be a viable option for a desired product, some opportunity factors are use of cheaper feedstock elimination of process step(s) or a difficult reaction avoidance of waste disposal, toxic materials, and/or abiUty to recycle reagent and abiUty to obtain products from anode and cathode. 

Heavy-walled drums once used for lead antiknock chemicals have been used for water storage or as barbecue pits, with subsequent risk to the user from residual toxic material. Equipment from the industry cited has for many years been cleaned, cut up, and sent under supervision to steel mills for recycle to eliminate the possible misuse of scrapped containers. 

Often an organization will strive for the elimination of a specific toxic material from a given process. Alternatives will also have other hazards and risks that require an informed choice. The industrial hygienist, chemist, and safety engineer play an important role in developing the information for making the selection between alternatives. 

---