Throstur Thorsteinsson ThrosturTh@hi.is Atrazine Herbicide, lead to widespread contamination in drinking water and is associated with birth defects and menstrual problems when consumed by humans at concentrations below government standards TBT Tributyltin compounds The main active ingredients in certain biocides used to control a broad spectrum of organisms DDT Silent Spring book written by Rachel Carson and published by Houghton Mifflin on 27 September 1962 Context important Not all natural state is harmless Pollution: refers to the occurrence of an unwanted change in the environment caused by the introduction of harmful materials - introduced through a) Point Sources b) Area Sources c) Mobile Sources Contamination: making something unfit for a particular use through the introduction of an undesirable material. Toxicity: Materials that are poisonous to living things. Carcinogen: a type of toxin that increases the risk of cancer. Synergism: the interaction of different substances resulting in a total effect greater than the sum of the effects of the separate sources. Measuring depends on the substance Common Units ppm: Parts per million (milligram per kilogram) ppb: Parts per billion (microgram per kilogram) mg/m 3 : Micrograms per cubic meter Always interested in concentration when the issue is levels of pollution. Infectious Agents Toxic Heavy Metals Organic Compounds Radiation Thermal Pollution Particulates Asbestos Electromagnetic Fields Noise Pollution Diseases are classified as infectious or noninfectious. Infectious agents: interact between individuals, soils, food, water, air etc. Environmental health concerns: Legionellosis - Lyme disease Giardiasis - Malaria Salmonella - Ebola Anthrax Throstur Thorsteinsson (ThrosturTh@hi.is) 1
Outbreaks of various infectious diseases Ebola Bird flue Incidents may increase with increased land conversion Incidents may increase with climate change Number of laboratory-confirmed cases of human infection with highly pathogenic avian infl uenza A(H5N1) virus Virus spread by Bats and Monkeys Causes internal bleeding 80% die that become infected High atomic weight Mercury, Lead, Cadmium, Nikkel, Gold, arsenic, selenium, chromium, tallium Been around since the stone age Stored in living tissue accumulate over time - biomagification in tissue. 10% of energy moved, but 100% of THM. Biomagnifications: the accumulation or increase in concentration of a substance in living tissue (e.g. fatty tissue) as it moves through a food web. Body burden: the quantity of metals that is toxic to humans. Drinking water inorganic mercury Maximum contaminant level: 2 ppb (0.002 mg/l) Pathways: Cadmium from burning coal. is absorbed by plants from ash. Concentration increases from ash to plant to humans Mercury from burning coal, processing metals Goes into waterways and is methylated by bacteria creating Methyl mercury (CH3HG). Absorbed by fish Concentration increases up food chain Throstur Thorsteinsson (ThrosturTh@hi.is) 2
Organic Compounds: Produced naturally and or synthetically - composed of carbon and hydrogen Persistent Organic Pollutants (POP): Synthetic organic compounds often containing chlorine. Do not easily break down in the environment Example PCB, dioxin Persistent Organic Pollutants: Carbon based structure, contain often highly reactive Cl Synthetic Polluting and toxic Soluble in fat accumulate in tissue Transported by wind, water and sediment Example PCB s, Dioxin The most toxic chemical ever made Colorless crystal (H, C, O, Cl) Byproduct from a chemical reaction created e.g. with the burning of municipal waste Hormonally Active Agents: Chemicals in the environment able to cause reproductive and developmental abnormalities in animals TBT DDT Phthalates Herbicides Pesticides Radiation: Radiation from nuclear power plants Natural radiation Radon baths Thermal pollution Heat released into water Changes average water temp and BOD causing changes in biota Small particles of dust Asbestos Soot Road dust Cause respiratory illnesses, cancer etc. Depending on type. Size matters the smaller the more dangerous Throstur Thorsteinsson (ThrosturTh@hi.is) 3
Radiation from electromagnetic fields Power lines Cell phones Appliances TV s No conclusive link to heath effects. Defined as unwanted sound Intensity measured in decibels (db) Average level at home 45 db Jet engine taking off 120 db Hearing loss 110 db But what really is noise pollution? Anything above 80 db is potentially dangerous. Changes in Abundance Changes in Distribution Changes in Birth Rates Changes in Death Rates Changes in Growth Rates The effect of a certain chemical on an individual depends on the dose Individuals differ in their response to chemicals Dose-Response Curve: - LD-50 (lethal dose 50) - ED-50 (effective dose 50) - TD-50 (toxic dose 50) Threshold Effects: - the level below which effects are not observable and above which effects become apparent Throstur Thorsteinsson (ThrosturTh@hi.is) 4
Changes in vegetation with distance from a toxic source Tolerance: The ability to resist or withstand stress resulting from exposure to a pollutant or harmful condition Acute and Chronic Effects Determines potential adverse environmental health problems. 4 steps 1. Identification of the hazard 2. Dose-Response assessment 3. Exposure assessment 4. Risk characterization The idea that in spite of the fact that full scientific certainty is often not available to prove cause and effect, we should still take cost-effective precautions to solve environmental problems where there exists a threat of potentially serious and/ or irreversible environmental damage Throstur Thorsteinsson (ThrosturTh@hi.is) 5