PH Finals Review 7 PDF

Chapter 7: Environmental Factors Study notes Environmental factors play a large role in the actual causes of death e.g., microbial agents Environment --> everything outside the body Environmental health --> public health discipline concerned with preventing human disease and injury from...

Chapter 7: Environmental Factors Study notes Environmental factors play a large role in the actual causes of death e.g., microbial agents Environment --> everything outside the body Environmental health --> public health discipline concerned with preventing human disease and injury from hazards in the environment Emphasis on the impact in humans (not just environmental science) Environmental hazards Chemicals ○ Particularly when there is an unexpected release of chemicals e.g., chemical spills e.g., DDT Radiation ○ e.g., radon Metals ○ e.g., lead Particles and fibers ○ e.g., air pollution Biological agents Toxins Environmental pathways --> carries the hazards Air Water (surface and groundwater) Soil Food Solid waste Non-food products Routes of exposure Inhalation (breathing) Ingestion (eating, drinking, hand-to-mouth) Absorption (contact with skin) Common health effects Cancer Neurological damage  Poisoning Lung and kidney disease Skin problems Endocrine system disorders Birth defects Food- and water-borne diseases Air - air pollution Causes ○ Combustion Power plants, motor vehicles ○ Industrial processes Toxic chemicals ○ Livestock Gases from animal waste Clean Air Act (1970) ○ Required EPA to set air quality standards ○ EPA has set National Ambient Air Quality Standards for 6 common "criteria pollutants" ○ Also addresses hazardous or toxic air pollutants known to cause serious health problems ○ Clean air act = legislative, EPA = executive branch ○ Criteria air pollutants Particulate matter Sulfur dioxide Carbon monoxide Nitrogen oxides Ground level ozone Lead Air pollution in the United States ○ Emissions have gone down despite the population going up ○ Progress on air pollution in US - figure in textbook Indoor air pollution ○ Tobacco smoke (second-hand smoke) ○ Radon gas ○ Formaldehyde from particleboard, plywood, and other building materials ○ Airborne microbes ○ Mold, dust mites, pet dander Water - water pollution Causes ○ Point-source pollution Sewage, industrial discharge  ○ Nonpoint source pollution Runoff from farms and roads Clean Water Act (1972) ○ Originally the federal water pollution control act (1948) ○ Objective: "to restore and maintain the chemical, physical, and biological integrity of the nation's waters" ○ Set quality standards for surface waters Lakes, rivers ○ Imposed controls on point-source pollution into lakes and rivers ○ Authorized funding for municipal wastewater treatment facilities Safe Drinking Water Act (1974) ○ Authorized EPA to establish minimum standards for local drinking water systems ○ Required monitoring of water quality and reporting of results to state governments ○ Maximum contamination levels have been set for ~100 contaminants ○ Note: does not regulate private wells Solid waste - garbage Solid waste disposal ○ 1972 - Marine Protection, research and sanctuaries act (ocean dumping act) Generally prohibited dumping of waste in the ocean Not completely prohibited ocean dumping Required EPA to develop criteria for evaluating permit applications for ocean dumping ○ 1976 - Resource conservation and recovery act Banned open dumps, set standards for sanitary landfills for municipal waste disposal Regulated handling of hazardous waste, requires tracking and permitting ○ 1980 - Comprehensive Environmental Response, Compensation, and Liability Act (superfund program) Required EPA to identify waste sites that threatened public health or the environment Authorized funding for emergency cleanup of these sites Food Food safety ○ Foodborne illness Salmonella, E. coli, listeria, norovirus, etc. ○ Pesticides ○ Mercury in fish ○ Other contaminants - anything that shouldn't be in your food and is harmful ○ Additives - vitamins/minerals, preservatives ○ Antibiotics and growth hormones  ○ Genetically modified organisms? FDA ○ Created by federal food and drug act (1906) ○ Regulates the manufacture, labeling, and sale of food and drugs ○ Responsible for safety of produce, seafood, and most packaged food US department of Agriculture (USDA) ○ Responsible for safety of meat and poultry Why is there so much federal legislation concerning environmental health? ○ Sometimes it's hard for individual states to control natural things e.g., the air doesn't care, it's just going to move e.g., fire in Idaho - the smoke moves to different states ○ Keeping the environment clean The environment can be polluted by individuals, but it cannot be kept clean only by individual efforts Pollution is an "externality" = it has costs to people other than those who produce it Can polluters be expected to voluntarily limit their level of polluting? ○ Government regulation Some important federal agencies in the US EPA - air, water, waste disposal FDA - packaged foods, produce, drugs, cosmetics, medical devices USDA - meat and poultry OSHA - workplace exposures CPSC - consumer products Set standards Limits for emissions, discharge, exposure Labeling requirements Safety specifications Government provision of services Water, sewer, trash collection Usually in metropolitan areas Laboratory testing Clean up spills Taxes, fees Research Identify hazards ○ How do we know something in the environment is harmful to human health? - epidemiology ○ When is exposure considered a public health problem - when a lot of people are affected Risk assessment ○ An analytic process leading to a judgment about the likelihood of adverse health effects to result from exposure to an agent in the environment ○ 4 steps Step 1 --> hazard identification Determining whether exposure to a particular agent causes adverse health effects in humans How? Epidemiological studies linking exposure to health outcomes Animal studies Step 2 --> dose-response assessment Determine the relationship between dose (amount of the agent) and response (adverse health effects) How much exposure to the agent is necessary before adverse health effects occur? Step 3 --> exposure assessment Estimate how many people are exposed to the agent and in what amounts Is the general population exposed? Is exposure limited primarily to people working in certain occupations? What is the duration of exposure? What concentrations of the agent are people exposed to? Step 4 --> risk characterization Overall conclusion about the presence or absence of risk and nature of the risk based on synthesis of steps one to three ○ Limits and challenges Tens and thousands of chemicals used Only a fraction have been studied for human health risk Even fewer are regulated (exposure limits) Most studies have focused on individual agents --> little is known about health effects resulting from exposure to combinations of various agents