Environment & Ecology 012 Environmental Health & Toxicology Ch 10
Central Case: Lake Apopka alligators In 1985, alligators in Lake Apopka, Florida, had bizarre reproductive problems Non-viable eggs, depressed or elevated hormone levels Endocrine disruptors: compounds that mimic hormones and interfere with the functioning of animals’ endocrine (hormone) systems
There are many types of environmental hazards Environmental health: assesses environmental factors that influence human health and quality of life There are 4 major types of environmental hazards: Physical Chemical Biological Cultural Much of environmental health consists of taking steps to address the impacts and risks of hazards. We can’t avoid risk, but we can minimize its effects.
Health & Environment Perspective of Relations Environmental health Public Health Occupational Health Family Health Personal Health
Chemical and biological environmental hazards Physical hazards: occur naturally in our environment Earthquakes, volcanoes, fires, floods, droughts UV radiation. We increase our vulnerability by deforesting slopes (landslides), channelizing rivers (flooding), etc. We can reduce risk by making better environmental choices.
Antarctica Sept 2011
Both UVA and UVB are responsible for photoaging and sunburn. Tanning beds produce both UVA and UVB rays
Melanoma facts From 1996 to 2000, the national average rate for melanoma was 17.5 for every 100,000 people, while the state of Hawaii average was 15.1 cases per 100,000.
Factors that may also influence the chance of getting melanoma include • Fair skin or freckles. • Being male. • Family or personal history of melanoma. • Chronic UV light exposure. • Severe sunburns. • Unusual moles or a large number of moles. • Weak immune system.
Chemical and biological environmental hazards Chemical hazards:synthetic chemicals such as pesticides, disinfectants, pharmaceuticals Harmful natural chemicalsalso exist.
Common Hazardous Waste Products • Bug spray • Floor care products • Furniture polish • Metal polish with solvent • Swimming pool acid • Glue (solvent based) • Paint, oil based • Paint, auto • Paint, model • Paint thinner • Fertilizer • Fungicide • Herbicide (weed killer) • Insecticide • Rat poison • Artists’ paints, mediums • Ammunition • Dry cleaning solvents • Lighter fluid • Mercury batteries • Moth-balls • Old fire alarms • Photographic chemicals (unmixed) • Antifreeze • Automatic transmission fluid • Battery acid (or batteries) • Brake fluid • Car wax with solvent • Diesel fuel • Gasoline • Kerosene • Motor oil
Hawaii Clean Energy Initiative • Must supply 70% clean energy by 2030. • 40% from renewable • 30% from efficiency Landfill gas (Kapaa) Waste to energy
Harmful Natural Chemicals ciguatera HAB botulism
Medical Waste Waimanalo Gulch Landfill overflowed into Ko’olina Jan 2011
Harmful Natural Chemicals metals (Al, Mg, Na, K, Cu, Zn, Cd, HG, Pb) gases: H2O, H2S, HCl, HBr, SO4, NO2, CO2 VOG
Cultural environmental hazards E. coli Biological hazards: result from ecological interactions • Viruses, bacteria, and other pathogens • Infectious (communicable, or transmissible) disease: other species parasitize humans, fulfilling their ecological roles HIV
Dengue fever Apr 2011 4 confirmed cases Leptospirosis Avian flu (2013) WCC
6/13/2006 Raw sewage dump in Ala Wai. Beaches Close! 48 million gallons 48 million gallons • Why? • 40 straight days of rain • 42-inch pressurized underground pipe broke during heavy rains
Cultural environmental hazards Cultural (lifestyle) hazards: result from the place we live, our socioeconomic status, our occupation, our behavioral choices • Smoking, drug use, diet and nutrition, crime, mode of transportation
Tobacco • There are over 4,000 chemicals found in tobacco smoke and over 400 toxins. • There are over 60 carcinogens proven to cause cancer in humans. • Causes 1 in 5 deaths in U.S. • Leading cause of cancer deaths
Hawaii Stats % of Adults who smoke by race/ethnicity 2010 • Smoking • Obesity (2010) • - 22.7% HI (5th lowest) • Diabetes • - 28.5 million U.S. (8.7%) • - 100,000 in HI (8.3%)
Disease is a major focus of environmental health Despite our technology, disease kills most of us. Disease has a genetic and environmental basis. Cancer, heart disease, respiratory disorders Malnutrition, poverty, and poor hygiene can foster illnesses.
Infectious diseases kill millions • Vector: an organism that transfers pathogens to a host
Many diseases are increasing • Tuberculosis, acquired immunodeficiency syndrome (AIDS), and the West Nile virus are increasing. • Our mobility spreads diseases. • Some diseases are evolving resistance to antibiotics. • Climate change will expand the range of diseases. • Habitat alteration affects the abundance, distribution, and movement of disease vectors.
Environmental health hazards exist indoors Radon: a highly toxic, colorless, undetectable radioactive gas Builds up in basements Can cause lung cancer Lead poisoning: from lead pipes, paint Damages organs, learning problems, behavior abnormalities, death Asbestos: insulates against heat, cold, sounds, and fire Asbestosis: scarred lungs don’t function Also causes a type of lung cancer Not a problem in Hawaii problem in Hawaii (<1978) Asbestos removal can also be dangerous Renovation issues
A recently recognized hazard • Polybrominated diphenyl ethers (PBDEs): has fire-retardant properties • Used in computers, televisions, plastics, and furniture • Persist and accumulate in living tissue • Affect thyroid hormones, may cause cancer, and affect brain and nervous system development • The European Union banned them in 2003. • The U.S. has not addressed this issue.
Toxicology is the study of poisonous substances Toxicology: the study of the effects of poisonous substances on humans and other organisms Toxicity: the degree of harm a chemical substance can cause “The dose makes the poison”: toxicity depends on the combined effect of the chemical and its quantity Toxicant: any toxic or poisonous agent During the past century, we have produced many new chemicals. Public concern for health and the environment
Environmental toxicology Deals with toxic substances that come from or are discharged into the environment Focuses mainly on humans, using other animals as test subjects Animals can serve as indicators of health threats. Don’t forget: chemicals have played a crucial role in giving us our high standard of living. Food, medicine, materials, convenience
Toxic agents in the environment The environment contains countless natural chemicals that may pose health risks. But synthetic chemicals are also in our environment. Every human carries traces of industrial chemicals. Very few chemicals have been thoroughly tested. 100,000 chemicals are on the market today. We don’t know the effects, if any, they have. 80% of U.S. streams contain at least trace amounts of 82 wastewater contaminants.
Silent Spring began public debate over chemicals Rachel Carson published Silent Spring in 1962. Brought together studies to show DDT risks to people, wildlife, and ecosystems In the 1960s, pesticides were mostly untested and were sprayed over public areas, assuming they would do no harm. DDT Powerful Insecticide Harmless to humans
Types of toxicants based on health effects Carcinogens: cause cancer Mutagens: cause DNA mutations Can lead to severe problems, including cancer Teratogens: cause birth defects Neurotoxins: assault the nervous system Heavy metals, pesticides, chemical weapons Allergens: overactivate the immune system Endocrine disruptors:interfere with the endocrine (hormone) system
Endocrine disruption may be widespread Theo Colburn wrote Our Stolen Future in 1996. Synthetic chemicals may be altering hormones. This book integrated scientific work from various fields. Shocked many readers and brought criticism from the chemical industry
Evidence for hormone disruption • Frogs also have gonadal abnormalities. • Male frogs exposed to very low levels of atrazine became feminized. • Levels were below EPA standards for human health. • The shocking drop in men’s sperm counts may be due to endocrine disruptors.
Endocrine disruption research is controversial • Scientific uncertainty is inherent in any young field. • Negative findings pose economic threats to chemical manufacturers. • Bisphenol-A, used in plastics, causes birth defects, but the plastics industry protests that the chemical is safe. • Pthalates affect male fetuses but are still used in toys and makeup in the U.S.
Toxicants are found in water and air • Water carries toxicants from land areas to surface water. • Chemicals can leach through the soil into groundwater. • Chemicals enter organisms through drinking or absorption. • Aquatic organisms (fish, frogs, stream invertebrates) are effective pollution indicators. • Because chemicals can travel by air, their effects can occur far from the site of use. • Pesticide drift: airborne transport of pesticides • Synthetic chemical contaminants are found globally. • Arctic polar bears, Antarctic penguins, and people living in Greenland
Toxic chemicals Pesticides & Herbicides • Designed to kill a variety of pests, such as mosquitoes, agricultural pests and weeds. • Toxin enters food chain and effects non targeted species • Pesticide toxicity often effects human health Bioaccumulation biomagnification
Toxic chemicals Pesticides Halogenated hydrocarbons or organochlorines: Include DDT and PCBs, which are slow to biodegrade • Dichloro-diphenyl-trichloro-ethane (DDT): • used as a pesticidefrom 1939-late 1960s • fatsoluble compound • the world’s production has substantially decreased since it was banned in the West • detected in mud of deep sea and snow & ice of Antarctica
Toxic chemicals • Polychloronated biphenyls (PCBs) • produced since 1944 • banned in U.S. by 1979 • used in production of electrical equipment, paints, plastics, adhesives, and coating compounds… • found everywhere in the ocean • released in env. by unregulated incineration of discarded products • DDT & PCBs affects: • copepod and oyster development • death of shrimp and a variety of fish
Toxic chemicals Polychloronated biphenyls (PCBs) Concentrations of polychlorinated biphenyls (PCB's) in killer whales and humans.
Toxicants can accumulate and biomagnify Biomagnification
Toxic chemicals Toxic Metals Hg, Pb, Cd, Cu, Ar Heavy metals resist biodegredation Natural occurrence- volcanoes • Mercury (Hg)- toxic when attached to short carbon-chain alkyl group, strongly neurotoxic, birthdefects • Lead (Pb)- from batteries, sewage, fuel additives, neurotoxic effects, mental development in children • Cadmium (Cd)- from batteries, sewage, electroplating factories, effects on human kidney function, bone deformities
Heavy Metals • Minamata Disease (1953-1960)– Japan • Industrial pollution from plastic plant; dumped mercuric chloride into bay • Ingestion of Hg tainted shellfish 43 dead and 700 permanently disabled