Statistically controlled clinical studies on humans provide the best evidence linking a stressor, often a chemical, to a resulting effect. In the case of chemical stressors, the process examines the available scientific data for a given chemical (or group of chemicals) and develops a weight of evidence to characterize the link between the negative effects and the chemical agent.Įxposure to a stressor may generate many different adverse effects in a human: diseases, formation of tumors, reproductive defects, death, or other effects. It is also whether the adverse health effect is likely to occur in humans. Hazard Identification is the process of determining whether exposure to a stressor can cause an increase in the incidence of specific adverse health effects (e.g., cancer, birth defects). Step 1: Hazard identification is the first step of a human health risk assessment. Is there a critical time during a lifetime when a chemical is most toxic (e.g., fetal development, childhood, during aging)? Chronic - a significant part of a lifetime or a lifetime (for humans at least seven years).Subchronic - weeks or months (for humans generally less than 10% of their lifespan).Acute - right away or within a few hours to a day.How long does it take for an environmental hazard to cause a toxic effect? Does it matter when in a lifetime exposure occurs?.Example of some health effects include cancer, heart disease, liver disease and nerve disease.Excretion - how does the body get rid of it?.Metabolism - does the body break down the environmental hazard?.Distribution - does the environmental hazard travel throughout the body or does it stay in one place?.Absorption - does the body take up the environmental hazard.What does the body do with the environmental hazard and how is this impacted by factors such as age, race, sex, genetics, etc.?).Non-dietary ingestion (for example, "hand-to-mouth" behavior).Routes (and related human activities that lead to exposure).Non-food consumer products, pharmaceuticals.Pathways (recognizing that one or more may be involved).Non-point sources (for example, automobile exhaust agricultural runoff).Point sources (for example, smoke or water discharge from a factory contamination from a Superfund site).Where do these environmental hazards come from?.Socio-Economic ( for example, access to health care).Nutritional (for example, diet, fitness, or metabolic state).Chemicals (single or multiple/cumulative risk).What is the environmental hazard of concern?.Population subgroups - highly susceptible (for example, due to asthma, genetics, etc.) and/or highly exposed (for example, based on geographic area, gender, racial or ethnic group, or economic status).Lifestages such as children, teenagers, pregnant/nursing women.To start, risk assessors will typically ask the following questions: Before anything though there is a need to make judgments early when planning major risk assessments regarding the purpose, scope, and technical approaches that will be used. Even a human health risk assessment starts with a good plan.
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