Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
ENSC 201* Winter 2005 Winn Natural chemical hazards: ENSC 201 Any type of chemical hazard caused by earth’s natural processes Geological hazards: -earthquakes, volcanoes, landslide Natural chemical hazards Weather/climate: -hurricanes, tornadoes, wildfires, avalanches Louise Winn School of Environmental Studies Rm 3127, BioSciences Complex [email protected] Biological hazard: -plant toxins, bacterial toxins, aflatoxin, snake venom, Environmental Toxicology. D.A. Wright and P. Welbourn. Cambridge Press, 2002 1 2 Forest Fires Volcanoes Significant force for environmental change • Primary: direct contact with the eruption and its material • • Carbon dioxide • Methane • Nitrous oxide Lava, ash-respiratory-also efficient at grabbing and holding molecules of gas like sulfuric acid ∴ can release these gases into the ground killing crops and upsetting the chemistry of ground water • • • • • Landslides (water combining with ash) Iceland-lava melts ice Climate change • • SO2 + H2O ⇒ H2SO4 – Stays aloft for 2-3 years, cooling effect of 0.2-0.3C, can shorten the growing period by 1 week Trap heat • Smoke and aerosol • Secondary: effects that arise from products or derivatives of the eruption Cooling effect-trap and block sunlight Indonesia-1997 released as many greenhouse gases as all the cars and power plants in Europe emit in an entire year Soames Summerhays/Photo Researchers, Inc. 3 4 Definitions Toxic effects of plants • Toxin: toxic substance produced by plants, animals, fungi or bacteria (biological) • Different portions of the plant often contain different concentrations of a chemical • Age • Climate and soil • Genetic differences within a species • Toxicant: toxic substance produced as a result of human activity • EXPOSURE • • • • • • Xenobiotic: compounds not known to occur in nature » Foreign chemical 5 Major part of diet Agriculture Plant contamination in food Accidental ingestion Herbal medicines 6 1 ENSC 201* Winter 2005 Winn Toxic effects of plants Discourage herbivores and inhibit bacteria or fungal pathogens Bacterial toxins • Foxglove • Lipopolysaccharides-endotoxins-associated with the cell wall • Exotoxin: soluble proteins secreted by living bacteria – Digitalis purpurea – Digoxin • Strengthens heart contraction, used to treat congestive heart failure – Bacterial protein toxins are the most powerful human poisons known • Strychnine – Strychnos nux-vomica – Causes powerful convulsions – Used as a pesticide • Diphtheria toxin – Corynebacterium diphtheriae – Inhibits protein synthesis • Ricin – Ricinus communis – Castor bean plant, seeds that are poisonous-ricin is water soluble therefore not in oil – When ingested, ricin causes severe gastrointestinal symptoms followed by vascular collapse and death- acts by inhibiting protein synthesis • Anthrax toxin – Bacillus anthracis • Poison ivy-toxicodendrol, sticky sap 7 8 Fungal Toxins Toxic Effects of Animals • Venom: proteolytic enzymes, blood coagulation, cardiac and pulmonary dynamics snake frog Spiders • Mushroom poisoning (Amanita muscaria, Psilosybe) -Hallucinogenic-psilocibin, psilocin -Muscimol and ibotenic acid proteolytic enzymes blood coagulation cardiac and pulmonary dynamics destabilization of cell membranes • Aflatoxin – Aspergillus flavus – Corn, peanuts, cotton seed – Necrosis (cell death) and cancer in animals • Puffer fish – – – – • Ergot Alkaloids – Infect grasses/grains/rye – Produce mycotoxin - ergotoxine 9 Tetradodoxin Neurotoxin-Synaptic transmission Death following paralysis Found in roe, liver, intestine, and skin BUT not meat 10 • Mussels and domoic acid • Toxin produced by marine algae • Part of structure is similar to glutamic acid • Neurotransmission-memory loss, coma, seizures 11 2