Chapter Twenty: The Environment and Human Health

Section One: Pollution and Human Health Environmental Effects on Health Pollution causes illness by Directly by poisoning Indirectly by spreading infectious diseases People in developing countries suffer more and usually become ill due to polluted water

Section One: Pollution and Human Health Toxicology The study of the harmful effects of substances on organisms Is the concentration of the chemical in the environment high enough to be harmful? Dose: the amount of a harmful chemical to which a person is exposed Dose-response curve: shows the relative effects of various doses of a drug or chemical on an organism

Section One: Pollution and Human Health Epidemiology the study of the spread of diseases Helps scientists try to trace the disease to find the origin Risk Assessment: an estimate of the risk posed by the action of a substance What is the chance that you will get the disease?

Section One: Pollution and Human Health Pollution from Natural Sources Some pollutants occur naturally in the environment Particulates: particles in the air that are small enough to breath into the lungs Ex: dust and soot Heavy metals Elements like arsenic, cadmium, lead and mercury Occur naturally in the rocks and soil Dangerous in high amounts

Section One: Pollution and Human Health Pollution from Human Activities Humans activities release thousands of chemicals Regulations made by the government have helped reduce some pollutants Some scientist believe chemical pollution may be the cause of Parkinson’s and Alzheimer’s diseases Burning fuels causes many health defects Pesticides Waste Disposal Industrial Chemicals Used in building materials, carpets, cleaning fluids, and furniture

Section Two: Biological Hazards The Environment’s Role in Disease Pathogens: organisms that cause disease Host: an organism in which the pathogen lives all or part of its life Waterborne Disease Diseases transmitted through water Vectors: organisms that transmit diseases Mosquitoes Cholera Caused by water polluted with human feces Malaria Caused by parasitic protists found in mosquitoes

Section Two: Biological Hazards Environmental Change and Disease Many ways we alter the environment make it more suitable for pathogens Antibiotic Resistance The overuse of antibiotic has led to pathogens developing resistance to them

Section Two: Biological Hazards Environmental Changes and Disease Malaria Transmitted through mosquitoes Mosquitoes breed in water Have developed resistance to pesticides Emerging Viruses AIDS and HIV No drugs for treatment of viruses Only vaccine to prevent certain viruses Cross-Species Transfer Pathogens can move from one species to another Many diseases started in wild animals and were transferred to humans