Risk characterization, human health

Risks to human health and the environment will vary considerably depending upon the type and extent of exposure. Responsible authorities are strongly encouraged to characterize risk on the basis of locally measured or predicted exposure scenarios. To assist the reader, examples of exposure estimation and risk characterization are provided in CICADs, whenever possible. These examples cannot be considered as representing all... 

In this chapter the risk assessment is briefly introduced. Risk assessment is divided into four steps hazard identification, hazard characterization, exposure assessment, and risk characterization. This chapter also highlights five risk and life cycle impact assessment models (EUSES, USEtox, GLOBOX, SADA, and MAFRAM) that allows for assessment of risks to human health and the environment. In addition other 12 models were appointed. Finally, in the last section of this chapter, there is a compilation of useful data sources for risk assessment. The data source selection is essential to obtain high quality data. This source selection is divided into two parts. First, six frequently used databases for physicochemical... 

Due to this, it is necessary to assess the risk to human health and the environment due to the exposure to these chemical additives. In this chapter the impacts that a substance can cause to a certain receptor (humans and the environment) and the harms to the receptor at different exposure levels are identified in hazard identification and hazard characterization steps, respectively. Exposure assessment takes into account the amount, frequency, and duration of the exposure to the substance. Finally, risk characterization evaluates the increased risk caused by such exposure to the exposed population. 

However, the exceptional size-specific behavior of nanomaterials in combination with their relatively large surface-to-volume ratio might result in potential risk for human health and the environment [26-28]. For example, fullerene (C60) particles suspended in water are characterized by antibacterial activity against Escherichia coli and Bacillus subtilis [29] and by cytotoxicity to human cell lines [30]. Single- and multiwalled carbon nanotubes (CWCNTs and MWCNTs) are toxic to human cells as well [31, 32]. Nano-sized silicon oxide (Si02), anatase (Ti02), and zinc oxide (ZnO) can induce pulmonary inflammation in rodents and humans [33-35],... 

See also Benchmark Dose Exposure Assessment Exposure Criteria Hazard Identification Hormesis, LD50/ LC50 (Lethai Dosage 50/Lethai Concentration 50) Levels of Effect in Toxicoiogicai Assessment Maximum Allowable Concentration (MAC) Maximum Tolerated Dose (MTD) Pharmacokinetics/Toxicokinetics Reference Concentration (RfC) Reference Dose (RfD) Risk Assessment, Ecological Risk Assessment, Human Health Risk Characterization Toxicity, Acute. 

See also Ames Test Analytical Toxicology Animal Models Biomarkers, Human Health Epidemiology Good Laboratory Practices (GLP) In Vitro Test In Vivo Test Risk Assessment, Human Health Risk Characterization Toxicity, Acute Toxicity, Chronic Toxicity, Subchronic. 

See also Clean Air Act (CAA), US Clean Water Act (CWA), US Federal Insecticide, Fungicide, and Rodenti-cide Act, US Food, Drug, and Cosmetic Act, US Risk Assessment, Ecological Risk Assessment, Human Health Risk Characterization Risk Management Safe Drinking Water Act, US Toxic Substances Control Act, US. 

See also Risk Assessment, Ecological Risk Assessment, Human Health Risk Characterization Risk Management. 

Low dose radiation research - to understand and characterize the risks to human health from exposures to low levels of radiation. 

As discussed in the previous problem set, the four major steps in a health risk assessment are hazard identification, dose-response assessment, exposure assessment, and risk characterization. A health risk assessment initially involves the identification of human health effects attributed to exposure to a chemical, usually on a continuous basis. A dose-response assessment determines how different levels of exposure to a hazard or pollutant affect the likelihood or severity of the health effects. An exposure assessment determines the extent of human exposure. These are combined to provide a risk characterization value. 

Ecological risk assessment is an integral part of theRI/FS process, which is designed to support risk management decision-making for Superfund sites. (The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 [CERCLA, or Superfund], as amended by the Superfund Amendments and Reauthorization Act of 1986 [SARA], authorizes the USEPA to protect public health and welfare, and the environment from the release or potential release of any hazardous substance, pollutant, or contaminant.) The RI component of the process characterizes the nature and extent of contamination at a hazardous waste site and estimates risks to human health and the environment posed by contaminants at the site. The FS component... 

Product stewardship means "responsibly managing the health, safety, and environmental aspects of raw materials, intermediate, and consumer products throughout their life cycle and across the value chain in order to prevent or minimize negative impacts and maximize value" [7], Chapter 2 of this book discusses the technical tools that a product steward uses to achieve this goal. These tools include the techniques to characterize and predict the fate and transport of chemicals in the environment upon their manufacture and use. The tools also include the methods used to calculate the possible risks to human health and the environment that may result. Chapter 2 also describes the formal process of life cycle assessment, which uses these tools to evaluate the potential effects on the environment as a result of the production, use, and disposal or recycling of a product. 

Risk characterization combines the results of the hazard assessment and exposure assessment to project the potential risk to human health or the environment. The way in which it is done in the European Union under REACH illustrates the process [76]. 

A risk characterization comprises a series of evaluations, each pertaining to a specific population, route of exposure, and frequency and duration of exposure. (ECHA refers to this combination of factors as the "exposure pattern") Assessors characterize the risk to human health by comparing the estimated exposure level for a given exposure pattern with the lowest DNEL/DMEL value for that exposure pattern. If the exposure could exceed the DNEL/DMEL, resulting in a risk characterization ratio (RCR) above 1, then the risk could be significant. 

Most human or environmental healtli hazards can be evaluated by dissecting tlie analysis into four parts liazard identification, dose-response assessment or hazard assessment, exposure assessment, and risk characterization. For some perceived healtli liazards, tlie risk assessment might stop with tlie first step, liazard identification, if no adverse effect is identified or if an agency elects to take regulatory action witliout furtlier analysis. Regarding liazard identification, a hazard is defined as a toxic agent or a set of conditions that luis the potential to cause adverse effects to hmnan health or tlie environment. Healtli hazard identification involves an evaluation of various forms of information in order to identify the different liaz.ards. Dose-response or toxicity assessment is required in an overall assessment responses/cffects can vary widely since all chemicals and contaminants vary in their capacity to cause adverse effects. This step frequently requires that assumptions be made to relate... 

Dose-Response Evaluation The process of quantitatively evaluating toxicity information and characterizing the relationship between the dose a contaminant administered or received, and the incidence of adverse health effects in the exposed population. From a quantitative dose-respoiise relationship, toxicity values can be derived that are used in the risk characterization step to estimate the likelihood of adverse effects occurring in humans at different exposure levels. 

Risk characterization is lire process of estimating llie incidence of a health effect under the various conditions of human or animal exposure described in lire exposure assessment. It is performed by combining the exposure (see Cliapter 12) and dose response (see Cluipter 11) assessments. The summary effects of the uncertainties in lire preceding steps should also be described in lliis step. 

A risk estimate indicates the likelihood of occurrence of the different types of health or enviromiiental effects in exposed populations. Risk assessment should include both human healtli and environmental evaluations (i.e., impacts on ecosystems). Ecological impacts include actual and potential effects on plants and animal (otlier than domesticated species). The numbers produced from the risk characterization, representing tlie probability of adverse health effects being caused, must be evaluated. 

Hazard characterization is a quantitative or semi-quantitative evaluation of the nature, severity, and duration of adverse health effects associated with biological, physical, or chemical agents that may be present in food. The characterization depends on the nature of the toxic effect or hazard. Eor some hazards such as genotoxic chemicals, there may be no threshold for the effect and therefore estimates are made of the possible magnitude of the risk at human exposure level (dose-response extrapolation). 

Encouraged by recent legislations all over the world aimed to protect human health and environment, alternative methods have proved their abilities to assess the toxicity of chemicals. Hence, a possible solution to the characterization of the toxicological and ecotoxicological risk of the chemicals could be represented by the application of in silico and in vitro techniques. 

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