Chemical dealing with exposures

The popular movie Erin Brockovich, although focusing on the power industry, is an example of how the popular media can simplify the public s perception of chemical exposure. In Erin Brockovich the chemical of concern was hexavalent chromium, Cr +. Hexavalent chromium is listed as a carcinogen by EPA, but complicated questions dealing with exposure (drinking, inhalation, absorption through skin), toxicity levels, and specific health effects were lost in Hollywood s version. 

Safety/Health and Environmental Affairs are often interwoven in practice, especially where process emissions, chemical exposure, and waste disposal can impact on public health. Many, if not most, companies with chemical synthesis plants in populated areas work with local communities to foster good relations sometimes via open house days or in the creation of action plans to deal with adverse events which may occur in plant operation. The presentation on Environment (Chapter 5) addresses the canon that has developed to deal with exposure to chemicals, with the impact of spills and emissions on all life forms and with waste recycle, treatment, and disposal. 

Treatment for Exposure — "First-aid" procedures are reconunended. They deal with exposure to the vapor (gas), liquid, or solid and include inhalation, ingestion (swallowing) and contact with eyes or skin. The instruction "Do not induce vomiting" is given if an unusual hazard is associated with the chemical being sucked into the lungs (aspiration) while the patient is vomiting. "Seek medical attention" or "Call a doctor" is recommended in those cases where only competent medical personnel can treat the injury properly. In all cases of human exposure, seek medical assistance as soon as possible. The sources of these recommendations are entirely from product specific MSDSs. 

Dealing with Exposure to Highly Toxic Chemicals... 

This chapter deals with exposure to common organic solvents which are used in large quantities to dissolve fats, resins, and other materials. Very dangerous chemicals, such as benzene, which are no more used as solvents due to their toxic properties, will not be discussed even though they may have had extensive uses as solvents earlier and even though those may be still important chemicals as petroleum components or as intermediates for other chemicals. Also, solvents with very specialized uses, such as carbon disulfide the use of which is practically limited to viscose rayon industry and laboratories, are only shortly considered. Exposure data presented originate mainly from literature however, some unpublished data obtained from the Finnish Institute of Occupational Health (FIOH) has been added to indicate the order of magnitude of current exposure levels in industrialized countries (data cover the years 1994-1996). 

When working with chemicals that have target organ effects it is critical to prevent exposure. This is especially true if you have a pre-existing condition, disease, or injury to that particular organ. Read the MSDS to fmd out the most effective personal protection equipment (PPE) for dealing with the chemical and be certain to minimize release of the chemical in the first place. 

Ecotoxicology deals with the study of the harmful effects of chemicals in ecosystems. This includes harmful effects upon individuals, although the ultimate concern is about how these are translated into changes at the levels of population, commnnity, and ecosystem. Thns, in the conclnding sections of the chapter, emphasis will move from the distribntion and environmental concentrations of pollutants to conseqnent effects at the levels of the individnal, population, community, and ecosystem. The relationship between environmental exposure (dose) and harmful effect (response) is fundamentally important here, and full consideration will be given to the concept of biomarkers, which is based on this relationship and which can provide the means of relating environmental levels of chemicals to consequent effects npon individuals, populations, communities, and ecosystems. 

In general, it is easier to use models such as these to predict the distribution of chemicals (i.e., relationship between exposure and tissue concentration) than it is to predict their toxic action. The relationship between tissue concentration and toxicity is not straightforward for a diverse group of compounds, and depends on their mode of action. Even with distribution models, however, the picture can be complicated by species differences in metabolism, as in the case of models for bioconcentration and bioaccumulation (see Chapter 4). Rapid metabolism can lead to lower tissue concentrations than would be predicted from a simple model based on values. Thus, such models need to be used with caution when dealing with different species. 

When evaluating the safety of chemicals in humans, it is very important to know the fate of chemicals in the human body and the amounts of exposure in daily activity. This section reviews the metabolic reactions of pyrethroids in humans, and the biomonitoring of pyrethroid metabolites in human urine for the exposure assessment. Mathematical modeling is a useful tool to predict the fate of chemicals in humans. This section also deals with the recent advance of mathematical modeling of pyrethroids to predict the pharmacokinetics of pyrethroids. 

Chemical Exposure Index (CEI) (Chemical Exposure Index, 1994 Mannan, 2005, pp. 8/22-8/26.) The CEI provides a method of rating the relative potential of acute health hazard to people from possible chemical release incidents. It may be used for prioritizing initial process hazard analysis and establishing the degree of further analysis needed. The CEI also may be used as part of the site review process. The system provides a method of ranking one risk relative to another. It is not intended to define a particular containment system as safe or unsafe, but provides a way of comparing toxic hazards. It deals with acute, not chronic, releases. Flammability and explosion hazards are not included in this index. To develop a CEI, information needs include... 

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