Toxic chemicals contamination

It is beyond the scope of this book to examine all the sources of toxic chemical contamination of foods consumed by humans. The sections that follow address the absorption of xenobiotic chemicals via plant and animal growth and by the addition of toxic chemicals to food during its preparation and packaging. 

During the past decade, the State Water Resources Control Board, California s environmental protection agency for water quality, has learned that we have not done enough to prevent the growing problem of toxic chemical contamination of our ground water. 

The types of chemical contaminants that are present in water are numerous. The chemical species emerging as contaminants is ever increasing. It is estimated that 1000 new chemicals are identified in water each year. Setting standards for and monitoring such a wide array of chemicals are impractical. Acute health problems are seldom associated with toxic chemical contaminants in water except on rare cases of massive accidents where a chemical may be introduced into the water supply in very large amounts. This type of contamination is also rarely dangerous, because often the toxic chemical makes the water unsuitable for consumption due to unacceptable taste, odor, or color. Microbial contaminants, on the other hand, have acute and widespread effects, and thus require a higher priority. 

Chen H, Zheng J, Zhang X, Luo M, Wang Z, Qiao X (2007) Surface desorption atmospheric pressure chemical ionization mass spectrometry for direct ambient sample analysis without toxic chemical contamination. J Mass Spectrom 42 1045-1056... 

A monitor is defined as a device used to locate chemical agent (toxic chemical) contamination and/or to confirm decontamination of chemical agents (toxic chemicals). The use of a monitor implies a requirement for an operator to perform judgements with respect to the response of the device prior to taking action. Speed of response and recovery from an exposure is critical in the design of a monitor. 

Chen, H. Zheng, J. Zhang, X. Luo, M. Wang, Z. Qiao, X. Surface Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry for Direct Ambient Sample Analysis Without Toxic Chemical Contamination. J. Mass Spec-trom. 2007,42, 1045-1056. 

In nonindustrial settings, MCS substances are the cause of indoor air pollution and are the contaminants in air and water. Many of the chemicals which trigger MCS symptoms are known to be irritants or toxic to the nervous system. As an example, volatile organic compounds readily evaporate into the air at room temperature. Permitted airborne levels of such contaminants can still make ordinary people sick. When the human body is assaulted with levels of toxic chemicals that it cannot safely process, it is likely that at some point an individual will become ill. For some, the outcome could be cancer or reproductive damage. Others may become hypersensitive to these chemicals or develop other chronic disorders, while some people may not experience any noticeable health effects. Even where high levels of exposure occur, generally only a small percentage of people become chemically sensitive. 

Costs of downstream processing for purely chemical synthesis would be increased by 1) low specificity of reactions (giving rise to chemical contaminants closely related to the desired product) and 2) the toxic/corrosive nature of the chemicals. 

False. When someone smokes tobacco, the air becomes contaminated with tobacco smoke over a wide area. This can be particularly thick when several people smoke in the same room. This smoke contains high levels of toxic chemicals and can lead even in the non-smoker to all of the diseases associated with smoking. 

Swoboda-Colberg NG (1995) Chemical contamination of the environment sonrces, types, and fate of synthetic organic chemicals. In Microbial transformation and degradation of toxic organic chemicals (Eds LYYoung and CE Cerniglia), pp. 27-74. Wiley-Liss, New York. 

J.N. Seiber, Analysis of chemical toxicants and contaminants in foods, in Food Toxicology, ed. W. Helferich and C. K. Winter, CRC Press, Boca Raton, FL, Chapt. 9 (2001). 

One of the most obvious benefits of plants is the potential for production scale up, leading to the production of virtually limitless amounts of recombinant antibody at minimal cost Plants are easy to grow, and unlike bacteria or animal cells their cultivation is straightforward and does not require specialist media, equipment or toxic chemicals. It has been estimated that plantibodies could be produced at a yield of 10-20 kg per acre at a fraction of the cost associated with production in mammalian cells [2,18] The use of plants also avoids many of the potential safety issues associated with other expression systems, such as contaminating mammalian viruses or prions, as well as ethical considerations involving the use of animals. 

Immobilized cells have been extensively used for the production of useful and biologically important chemicals [42, 43], for the treatment of wastewaters [44 -6], and for bioremediation of soil contaminated with numerous toxic chemicals. Immobilization not only simplifies separation and recovery of the immobilized bacteria and the binding agent, but it also makes the application reusable, which... 

In addition to its broad occurrence under contrasting conditions, easy collection, relatively long life span, and resistance to the accumulation of toxic chemicals, zebra mussels provide a link between the pelagic and benthic food webs, possibly creating a rapid pathway for contaminant transfer from sediments to predators such as common carp (Cyprinus carpio) and, occasionally, humans [32, 42—4-7]. Consequently, zebra mussel has been considered a potential sentinel organism for assessing Hg redistribution from point sources in the Ebro River and the degree of bioavailability to river and wetland food webs. 

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