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