APES CHAPTER 17 TOXICOLOGY “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy." Paracelsus ( )

Risk: probability of suffering harm from a hazard that can cause injury, disease, death or economic loss or damage Risk assessment: evaluate risk associated with a hazard Risk management: implement plan of action Cost-benefit analysis Risk-benefit analysis Biological, chemical, natural, cultural and lifestyle hazards Hazard: anything that can cause injury, disease, or death to humans; damage to personal or public property; deterioration or destruction of environmental components

BIOLOGICAL HAZARDS Infectious disease (flu, malaria, TB) Caused by a pathogen (virus, bacteria, protists, fungi, helminths--worms) Transmissible disease (measles, HIV) Non-transmissible disease (cancer, asthma, diabetes, malnutrition) Not caused by pathogen Major concerns include flu, AIDS (HIV), Hepatitis B, malaria and emergent diseases (West Nile, Ebola) 94% of all deaths attributed to infectious disease are from AIDS, respiratory viruses, and diarrheal disease

BIOLOGICAL HAZARDS Factors that contribute to chronic diseases (heart disease, diabetes, emphysema…) more prevalent in developed nations High blood pressure, tobacco use, high blood glucose, obesity In developing countries chronic disease (respiratory and diarrheal infections) risk factors include Unsafe sex, alcohol use, indoor smoke (cooking fires), unsafe water, malnutrition Eliminate through infectious disease prevention, education, vaccines, improving quality of life and decreasing malnutrition

CHEMICAL HAZARDS Toxic chemical: can cause temporary or permanent harm or death to humans or animals Top 5 include: arsenic, lead, mercury, vinyl chloride (plastics) and PCBs Neurotoxin: chemicals that disrupt the nervous system of animals Insecticide, lead, mercury Endocrine disruptor: interfere with normal hormone functioning Medications, atrazine, pesticides Carcinogen: promotes cancer Arsenic, benzene, formaldehyde, gamma and UV radiation, PCBs, radon, tobacco smoke, vinyl chloride, asbestos Mutagen: increases frequency of mutations Teratogen: cause harm or birth defects to fetus/embryo Alcohol, benzene, formaldehyde, lead, mercury, PCBs, phalates, thalidomide, vinyl chloride

EVALUATING CHEMICAL HAZARDS Toxicity: measure of the harmfulness of the product Dose: amount ingested, inhaled, or absorbed Response: damage to health, may be acute or chronic Depends on age, genetic makeup, solubility of compound (water vs. oil) and persistence Dose-response Studies Tests on animals with measure doses of chemical Plot results of chemical tests to determine curve and lethal doses

LD 50 Lethal dose 50: Amount of chemical that kills 50% of a test population within 18 days. Varies depending on substance Determines if a new substance is more or less lethal than other chemicals used Usually tested on rats…then extrapolated to humans Gives values for acute toxicity Lower LD 50 = More toxic

ENVIRONMENTAL POLLUTANTS Pollution: the presence of a substance in the environment that prevents the functioning of natural processes and produces undesirable environmental or health effects Increases with growing population and expanding use of resources Effects can be aesthetic (not pretty), globalized or local Pollutant: any material that causes pollution Usually by-products of normal/essential activities

TOP ENVIRONMENTAL POLLUTANTS Asbestos Indoor air pollutant From ceiling tiles and pipe insulation Impacts human health (lung cancer, mesothelioma) CFCs Atmospheric air pollutant From air conditioners and refrigerators Impacts ozone layer (greenhouse gas) Carbon Monoxide (CO) Air pollutant (indoor/outdoor) From burning of fossil fuels Impacts atmosphere (weak greenhouse gas) and human health Carbon Dioxide (CO 2 ) Air pollutant (indoor/outdoor) From respiration, combustion of organic material Impacts climate change (greenhouse gas) Dioxins Soil/water pollutant From industrial processes (by-product) Impacts endocrine/immune system, toxic to animals, bioaccumulation Disease Agents Water pollutant From animal/human waste Impacts…

TOP ENVIRONMENTAL POLLUTANTS Formaldehyde Indoor air pollutant From building materials, textiles, furniture Impacts… Lead Air, soil, water pollutant From industry, gas, paint Plant/animal impacts Mercury Air, soil, water pollutant From combustion of coal, burning, smelting Mutagenic impacts, bioaccumulation No x Air, water pollutant From combustion of fossil fuels Impacts air quality (smog), acid rain, increase tropospheric ozone Oil Water/soil pollutant Natural source, surface runoff, spills Impacts water quality, aquatic organisms (toxic) Oxygen Demanding Waste Water pollutant From sewage, industry, agriculture Impacts dissolve oxygen in water (anoxic)

TOP ENVIRONMENTAL POLLUTANTS Ozone Air pollutant From photochemical reaction with NO x and VOCs Impacts plants, respiratory irritant (asthma) Particulates Air pollutant From soot, dust, soil, smoke, industry Impacts photosynthesis, air quality Pesticides Air, Soil, water pollutant From agriculture, golf courses, urban runoff Impacts plant/animals, toxic, bioaccumulates Phosphates Water pollutant From fertilizer, sewage Impacts water quality (eutrophication) Radon Indoor air pollutant From radioactive decay of uranium Impacts human health (lung cancer) Sulfur Dioxide (SO 2 ) Air pollutant From combustion of coal Impacts air quality (acid rain), forms smog

LEGISLATION INVOLVED IN MANAGING TOXINS FIFRA (Federal Insecticide, Fungicide, Rodenticide Act)—1910 (1972) Initially set standards for pesticide quality, with little consideration for environmental impact 1972 shifted to EPA control, and focused on protecting environment and human health Clean Air Act to establish air quality standards designed to minimize the air pollution found most harmful to human health. Six pollutants were specifically targeted--particulate matter, sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NOx), and lead (Pb). Clean Water Act establishes and maintains goals and standards for U.S. water quality and purity eliminate the discharge of pollutants into rivers, lakes, streams and other waterways Toxic Substances Control Act—1976 Gave the EPA the ability to track the 75,000 industrial chemicals currently produced or imported into the United States. EPA repeatedly screens these chemicals and can require reporting or testing of those that may pose and environmental or human-health hazard. Stockholm Convention Seeks to protect human health from the 12 most toxic chemicals (includes 8 chlorinated hydrocarbon pesticides). CERCLA Also known as the "Superfund" Act. This regulates mineral processing wastes. Hazardous wastes dumped somewhere can also be cleaned up through government funding

THE DIRTY DOZEN Aldrin Dieldrin Chlordane DDT Endrin Mirex Heptachlor PCBs Toxaphene Dioxins Furans Hexacholorobenzene The following chemicals are classified as persistent organic pollutants (POPs)—they persist in the environment and bioaccumulate. They were identified under the Stockholm Convention of The US did not ratify this treaty.

NATURAL HAZARDS Hurricanes Floods Tornadoes Volcanic eruptions Earthquakes Landslides Forest fires Some effects preventable (warning systems, building techniques) others a consequence of where people choose to live

CULTURAL HAZARDS Where live Criminal activity Political unrest Economic development of the country Risk factors differ substantially between developed/developing (access to food, water, healthcare)

LIFESTYLE HAZARDS Engaging in risky behavior Smoking, drugs, alcohol Eating too much Driving too fast Occupational hazards sunbathing