Exposure management toxicity

One shortcoming in many field studies is a failure to address adequately exposure to toxic transformation products. In efforts to manage time and cost constraints, the concentrations of parent materials and transformation products are often added together to produce a total toxic residue amount. However, it is more appropriate to evaluate individual transformation products as their toxicity may be significantly increased (e.g. active oxons) or decreased (e.g. dehalogenation or dealkylation products) relative to the parent compound. 

Where complete containment is impractical, exhaust ventilation (preferably to a scrubber) can limit or eliminate exposure to toxic materials. The exhaust ventilation rate (velocity or volumetric rate) may be calculable for volatile liquids from spill size and vapor pressure (U.S. Environmental Protection Agency, Risk Management Program Guidance for Offsite Consequence Analysis, Appendix D, Equation D-l, 1999), but tests to determine concentrations in air usually would be needed for dusty processes and fugitive releases of gases. 

Environmentally Induced Illnesses Ethics, Risk Assessment and Human Rights. Thomas Kerns, Jefferson, NC McFarland, [in press]. Addresses the ethics of managing environmental health and ubiquitous toxicants (such as solvents, pesticides and artificial fragrances). The work includes recent medical literature on chronic health effects from exposure to toxicants and the social costs of these disorders relevant historic and human rights documents recommendations for public policy and legislation and primary obstacles faced by public health advocates. 

The poor are at higher risk of exposure to toxic and hazardous chemicals because of their occupations, living locations, and lack of knowledge about chemicals. Sound chemicals management can improve their living environment, and consequently their health, and can help increase their revenue (e.g. proper use of pesticides can boost crop yields and protect the productivity of freshwater and marine fisheries). 

The history of risk management reveals that the risk management options which are selected do influence the risk assessments that are performed. They are not independent. The fundamental aim of risk management is the reduction of exposure, because toxicity to humans is an inherent (and unchangeable) property of each chemical. Examples of exposure reduction include ... 

Managing pediatric victims of chemical terrorism is an especially difficult challenge. In addition to the obvious physiologic and anatomic differences compared to adults (Table 61.1), there are important psychological and behavioral differences that put children at risk (Rotenberg and Newmark, 2003). Anecdotal reports have claimed that children are likely to be the first to manifest symptoms, to develop more severe manifestations, and to be hospitalized for other related illnesses. In fact, it is anticipated that children will be overrepresented among the initial index cases in a mass civilian exposure to toxic chemicals. Children have many characteristics that make them vulnerable to toxic exposures. The smaller mass of a child automatically reduces the dose of toxic agents needed to cause... 

Although our military experience managing toxicity from nerve agent exposure is limited, exposures to related chemicals such as the OP class occur commonly each year in the USA. In 2006, there were a total of approximately 5,400 OP exposures across the USA (Bronstein et al, 2007). OPs, such as malathion, are commonly used as pesticides. OP toxicity manifests in a similar fashion as toxicity from nerve agents however, this chemical class is considerably less toxic. One case series of 16 children who experienced poisonings with OPs confirmed that pediatric patients present with toxicity differently than adults (Lifshitz et al, 1999). These children often did not manifest the classic muscarinic effects (such as salivary secretions and diarrhea) seen in adults. 

A variety of chemical agents were used as toxic inhalants during World War I of these, several are considered current threats. Some toxicants have current military relevance either because of their presence in stockpiles or because of their current or recent use in military operations in other countries. Other toxicants exist in large quantities as a result of their industrial use. Because of the military s preparedness in managing large-scale exposure to toxicants, such as poisonous gases, military assistance may be required in the event of a major accident involving toxic inhalants. 

Effects of Exposure to Toxic Gases-First Aid and Medical Treatment and Medical Management Guidelines for Acute Chemical Exposures [8, 9]. 

Additional acute toxic symptoms involve cardiac abnormalities, liver dysfunction, and kidney inflammation. Agitated psychotic behavior can occur. For additional information, refer to Effects of Exposure to Toxic Gases-First Aid and Medical Treatment and Medical Management Guidelines for Acute Chemical Exposures [1,2]. 

The key to managing toxic chemicals judiciously is the dose-effect relationship. This relationship correlates degrees of exposure with manifestations of toxicity. It shows the percent of exposed individuals who get sick as a function of their degree of contact with a toxic chemical. The dose-effect relationship has the potential to serve as a toxicological road map for how to use chemicals to improve the quality of life while lowering to acceptable levels the risk of making people sick. 

Controlling exposure is the principal strategy for managing toxic chemical risk. Risk consists of two components the toxicity of a chemical and the conditions of its use. Toxicity is an inherent property and cannot be controlled. Exposure can be reduced by managing the conditions under which a chemical is used. 

Although our military experience managing toxicity from nerve agent exposure is limited, exposures to related chemicals such as the OP class occur commonly each year in the United States. In 2006, there were a total of approximately 5,400 OP exposures across the United States (Bronstein et al., 2007). OPs, such as malathion, are... 

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