CES 210 1st Edition Lecture 9Environmental Science Lecture NineEnvironmental HealthHealth: a state of complete physical, mental, and social well-beingDisease: an abnormal change in the body’s condition that impairs physical or psychological function- Diet and nutrition, infectious agents, toxic chemicals, genetics, trauma and psychological stress all play roles in morbidity (illness) and mortality (death)Global Disease BurdenDisability-adjusted life years: combine premature deaths and loss of healthy resulting from illness or disability- Chronic conditions account for premature death and disease in both developed and developing countries today- Diabetes is on the increase. One-third of children born in Northern America today will develop diabetes in their lifetime due to poor diet and little exercise- WHO projects that psychological conditions could increase their share of the global disease burden from 10% to currently 15%Infectious Diseases- Communicable disease are still responsible for about one-third of all disease-related deaths- Majority in countries with poor nutrition, sanitation, and vaccination- New diseases test our defense in developed countries- Better nutrition, clean water, improved sanitation and inoculation of children could eliminate most of the deathsPathogensThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Pathogens are disease-causing organisms that include:- Viruses- Bacteria- Protozoans- Parasitic worms including flukes- Greatest loss of life in a single year from a pathogen was in 1918 when the flu epidemic killed 50 to 100 million people worldwideEmergent DiseasesEmergent Diseases: is one not previously known, or one that has been absent for at least 20 years- Bird flu- Ebola fever- HIV- Air travel makes it possible to spread emergent diseases around the globe quicklyConservation MedicineEcological disease: animal epidemics - White nose syndrome in bats is due to a fungus recently introduced into the eastern US- California sea lions have herpes 1 virus spread to them through human sewage- An imported fungus is killing oak, redwoods, and Douglas tress is California- Dermo, a parasite of oysters is spreading rapidly along the east coast due to climate warmingConservation medicine: examines how environmental changes threaten health of humans and natural communitiesPesticide ResistanceThe protozoan parasite that causes malaria is now resistant to most antimalarial drugs, while the mosquitoes that transmit the protozoan have developed resistance to many insecticides- Natural selection and the ability of organisms to evolve rapidly - Human tendencies to overuse pesticides speeds up this processAntibiotic ResistanceAntibiotics: are chemicals that kill or inhibit that growth of bacteria Many people do not finish the full-course, creating resistant strains of bacteriaAt least half of the 100 million antibiotic doses prescribed in the US every year are unnecessary or are the wrong drugAntibiotics are routinely fed to US farm animals to stimulate weight gain. These are excreted in urine andfeces, and find their way into surface waters where they create more antibiotic resistanceFunding health careHeaviest burden of illness born by poorest people who cannot afford a healthy environment or adequatehealth care- WHO estimates 90% of all disease burden occurs in developing countries where less than 10% ofall health care dollars are spentIncreased financial aid to developing countries could reduce the spread of pathogens and might stabilize population growth since parents whose children have a higher survival rate tend to have fewer offspringToxicologyToxicology: is the study of poisons and their effects on a living systemDangerous chemicals are divided into two broad categories:- Toxic: known poisons that damage of kill cells/tissues- Hazards: dangerous but not toxic Ex: flammable, irritantEcotoxicology deals with the interactions, transformation, fate, and effects of natural and synthetic chemicals in the biosphereToxinsAllergens: substances that activate the immune systemAntigens: substances that are recognized as foreign by white blood cells and stimulate the production of specific antibodies- Other allergens act indirectly by binding to other materials so they become antigenic- For example, formaldehyde and carbon monoxide that cause sick building syndromeImmune system Depressants: pollutants that depress the immune systemEndocrine Disrupters: disrupt normal hormone functions- Environmental estrogens: environmental contaminants which cause reproductive problems in animals even at very low dosesNeurotoxins: metabolic poisons that specifically attack nerve cells; most are extremely toxic and fast actingDifferent types act in different ways- Heavy metals: kill nerve cells- Anesthetics and chlorinated hydrocarbons; disrupt nerve cell membranes- Organophosphates and carbamates: inhibit signal transmission between nerve cellsMutagens: agents that damage or alter genetic material. Can lead to birth defects or turmorsTeratogens: specifically cause abnormalities during embryonic growth and developmentCarcinogens: substances that cause cancerMovement, distribution, and fate of toxinsSolubility: one of the most important characteristics in determining the movement of a toxinChemicals are divided into two major groups:- Those that dissolve more readily in water- Those that dissolve more readily in oilWater soluble compounds more rapidly through the environment and have ready access to cells via tissue fluidFat-soluble compounds need a carries to move through the environment, but once inside the body they penetrate tissues easily and cross membranes. They are stored in body fat and persist for many yearsExposure and susceptibilityAirborne toxins generally cause more ill health than any other exposureFood, water and skin contact are other ways to be exposed to toxinsLargest toxin exposure reported in industrial settingsCondition of organisms and timing of exposure also have strong influences on toxicity. Children more vulnerable than adultsBioaccumulation: selective absorption and storage of toxinsBiomagnification: toxic burden of a large number of organisms at a lower trophic level is accumulated and concentrated by a predator at a higher trophic levelPersistenceSome chemical compounds are very unstable and degrade rapidly under most conditions, thus their