The Health Risk Evaluation Process

In recent years, several guidelines and liandbooks have been produced to help c.xplain approaches for doing healtli risk assessments. As discussed by a special National Academy of Sciences comiuittec convened in 1983, most 

Risk assessment iinoKes the integration of the information and analysis associated with the above four steps to provide a complete characterization of the nature and magnitude of risk and the degree of confidence associated with tliis characterization. A critical component of the assessment is a full elucidation of the uncertainties associated witli each of die major steps. Under this broad concept of risk assessment are encompassed all of the essential problems of toxicology. Risk assessment takes into account all of the available dose-response data. It should treat uncertainty not by the application of arbitrary safety factors, but by stating them in quantitatively and qualitatively explicit tenns, so tluit they tire not hidden from decision makers. Risk assessment defined in tliis broad way, forces an assessor to confront all the scientific uncertainties and to set fortli in e.xplicit terms tlie means used in specific cases to deal with these uncertainties. An e. panded presentation on each of the four hcaltli risk assessment steps is provided telow. 

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The health risk evaluation process consists of four steps hazard identification, dose-response assessment or hazard assessment, exposure assessment, mid risk cliaracterization. 

Significance of the predicted impacts should be assessed in the process of impact evaluation or interpretation. At this stage the health risk estimates (quantitative and qualitative) are analyzed in terms of their acceptability against relevant regulatory and/or technical criteria environmental quality standards or exposure limits. 

To avoid the damage of human health and contamination of particular elements of the environment it is necessary to apply the risk management process which is significant and still rmderrated tool in the Czech Republic. No matter the characteristic and sector classification of the researched risk in the risk evaluation process it is possible to identify common elementary steps like the risk resources identification, to evaluate, to semi-quantify or quantify all risks, to propose and then to implement adequate preventive countermeasures for the critical risks. Within the waste disposal process in this phase this method must be applied, i.e. in the phase of a landfill planning, operations and closing. Just only in this was it is possible to reach an efficient risk control and reduction. 

After each issue outlined in the evaluation criteria has been developed for each corrective measure, the selection of the most appropriate alternative can be made. Trade-offs among health risks, environmental effects and other pertinent technical, environmental and human health factors enter into this decisionmaking process. In the RCRA context, cost is not a factor in the selection process except when two or more corrective measure alternatives are determined by EPA to provide similarly adequate levels of protection of human health and the environment. 

The first step is to identify the substances present at the workplace. As a starting point, knowledge of the process is needed in order to formulate a list of all chemical agents used in the establishment. The list should include not only primary products but also intermediate and final products, as well as reaction products and by-products. For the chemical agents in the list, it is necessary to know their chemical properties, especially hazardous ones their OEL values, including biological limit values and, where these are not available, other technical criteria that can be used to evaluate the risk. It is also helpful to include any information on the safety and health risks of those substances provided by the supplier or other readily available sources. This information on dangerous substances and preparations, in the form of safety data sheets, is intended primarily for industrial users, to enable them to take the measures necessary to ensure the safety and health of workers. 

The process for assessing environmental health risks Is complex Information regarding 1) the environmental agent, 2) the pathways by which exposure occurs, and 3) the biologic effects observed after exposure must be assembled and simultaneously evaluated Incomplete knowledge or Inadequate methodology In any of these three areas can severely Inhibit accurate or useful estimates of health risk ... 

Hazard identification is the process of collecting and evaluating information on the effects of an agent on animal or human health and well-being. In most cases, this involves a careful assessment of the adverse effects and what is the most sensitive population. The dose-response assessment involves evaluation of the relationship between dose and adverse effect. Typically, an effort is made to determine the lowest dose or exposure at which an effect is observed. A comparison is often made between animal data and any human data that might be available. Next is exposure assessment, in which an evaluation of the likely exposure to any given population is assessed. Important parameters include the dose, duration, frequency, and route of exposure. The final step is risk characterization, in which all the above information is synthesized and a judgment made on what is an acceptable level of human exposure. In the simplest terms, risk is the product of two factors hazard and exposure (i.e. hazard x exposure = risk). In real risk assessments, all hazards may not be known and exposure is often difficult to quantify precisely. As a result, the calculated risk may not accurately reflect the real risk. The accuracy of a risk assessment is no better than the data and assumptions upon which it is based. 

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