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Description
Flashcards by Dennis Jallah, updated more than 1 year ago
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Created by Dennis Jallah
almost 8 years ago
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| Question | Answer |
| Anthropogenic examples of the 20th century | Donora Episode of 1948 - killed 20 and sickened 7K in Donora, PA London Killer Smog (1952) - estimated 4K deaths above the normal daily count due to respiratory problems (i.e. bronchitis, pneumonia) |
| Carbon Monoxide | Source - motor vehicle emissions, burning fossil fuels, and incomplete combustion Significance - Combines with hemoglobin to form carboxyhemoglobin (poisonous) |
| Particle Pollutants | Dust Fumes Mist Smoke Aerosol |
| Natural Air Pollutants | Volcano eruptions Forst Fires Dust storms Salt particle aerosol from ocean Hydrocarbons from trees Pollen and spores from plants |
| Anthropogenic Air Pollutants | Combustion sources Exhaust emissions Industrial Processes Mining and drilling |
| Indoor Air Pollutants | Combustion products from heating, cooking, pesticides, tobacco smoking |
| Which layer of the ozone is considered "bad" ozone? "Good" ozone? | Bad - tropospheric ozone Good - stratospheric ozone |
| What are the six principal pollutants identified by US EPA? | Carbon Monoxide Nitrogen Oxides Sulfur Oxides Ozone Particulate Matter Lead |
| T/F - Chlorofluorocarbons (CFCs) are the major contributors of damage to the stratospheric ozone layer | True |
| Name some common toxicological features of metals | Metal must cross membrane in order to exert toxicity lipid-soluble metals readily penetrate membranes e.g. methyl mercury protein bound metals absorbed via endocytosis e.g. cadmium-metallothionein metals can be absorbed via passive diffusion e.g. lead |
| Major metals associated with toxicity | Lead, Mercury, Cadmium, Chromium and Arsenic |
| Define Water Pollution | Any physical, biological, or chemical change in water quality that adversely affects living organisms or makes water unsuitable for desired uses |
| Define and give an example of Point Source pollution | Discharge pollution from specific locations e.g. factories, power plants and drain pipes |
| Define and give an example of Nonpoint Source pollution | Scattered or diffused with no specific location of discharge* e.g. agricultural fields, feedlots, golf courses, residential construction sites *Also includes atmospheric deposition (contaminants carried by air currents and precipitated into watersheds or directly onto surface waters) |
| Sulfur Oxides | Sources - Coal and oil power plants Significance - Main component of acid deposition |
| Gaseous Air Pollutants | CO H2S CH4 SO2 CO2 NO2 O3 |
| Carbon Dioxide | Sources - product of complete combustion Significance - may cause greenhouse effect |
| Nitric Oxide | Sources - Automobile emissions, fossil fuel power plants Significance - pulmonary edema and impairment of lung function |
| Ozone (O3) | Sources - Automobile emissions, photochemical smog Significance - Damage to vegetation, lung irritant |
| What are the two heavy metals of greatest health concern regarding drinking water exposure? | Lead and arsenic |
| What are the two heavy metals of greatest health concern regarding food chain exposure? | Cadmium (responsible for Itai-Itai disease) and mercury (most widespread in North America) Also, pesticides such as DDT (organochlorine compound) |
| Excess of these nutrients can lead to "algal blooms" or eutrophication | Nitrates and phosphates |
| T/F - One potential adverse health effects of nitrate entering drinking water is anemia or blue baby disease? | True |
| Two most important sources of toxic organic chemicals in water are: | 1) improper disposal of industrial and household wastes 2) Runoff of pesticides from fields, roadsides, golf courses and lawns |
| Threshold limit values (TLVs) | refer to airborne concentrations of substances and represent conditions under which repeated exposure causes no adverse effects |
| Threshold limit value-time-weighted average (TLV-TWA) | concentration for a normal 8-hr workday or 40-hr workweek to which nearly all workers may be repeatedly exposed, day after day, without adverse effects. |
| Threshold limit value - short-term exposure limit (TLV-STEL) | maximal concentration to which workers can be exposed fora period up to 15-min continuously without suffering from irritation, chronic or irreversible tissue change, or narcosis of sufficient degree that would increase accident proneness, impair self-rescue, or materially work efficiency, provided that no more than four excursions per day are permitted, with at least 60min between exposure periods, and provided that the daily TLV-TWA is not exceeded. |
| Threshold limit value-ceiling (TLV-C) | the concentration that should not be exceeded even instantaneously |
| Biologic limit values (BLVs) | represent limits of amounts of substances to which the worker may be exposed without hazard to health or well-being as determined by measuring the workers tissues, fluids, or exhaled breath. |
| Immediately dangerous to life or health (IDLH) | conditions pose a threat of sever exposure to contaminants that are likely to have adverse cumulative or delayed effects on health |
| T/F - Metals interacting with enzymes may induce toxic action via either inhibition or activation | True |
| Carcinogenic metals | Known: arsenic, nickel, and certain chromium compounds Probable: beryllium, cadmium, cisplatin |
| What organ is most susceptible to metal toxicity | Kidney, main excretory organ, is particularly susceptible to cadmium and mercury. Note: water solubility increases nephrotoxicity |
| Metals can act directly on sex organs | Acute cadmium exposure can produce testicular injury Lead accumulation in the testes is associated with testicular degeneration, inhibition of spermatogenesis, and Leydig cell atrophy |
| How does acute metal exposure differ from chronic metal exposure? | Acute metal exposure causes irritations and inflammation of the respiratory tract Chronic exposure leads to fibrosis or carcinogenesis |
| What is the name of the metal binding protein responsible for regulating the intracellular bioavailability of cadmium, copper, mercury, silver, and zinc | Metallothionein (MT) |
| What are the main targets of lead toxicity? | Hematopoietic and nervous system |
| Organic mercury primarily affects the _____ system. | nervous system Note: Elemental mercury absorbed by the respiratory system and permeates the BBB, effecting the nervous system |
| Cadmium inhibits what organelle function? | Lysosomes Note: Very slowly excreted from the body. Long-term exposure damages the kidney. Transported via MT |
| What two forms of chromium are of biological significance? | Trivalent (Cr^+3) and hexavalent (Cr^+6) |
| T/F - High levels of arsenic may result in gangrene of the lower extremities or cancer of the skin? | True |
| What is used to reverse or prevent metal toxicity? | Chelating agents - formation of metal ion complex in which the metal ion is associated with an electron donor ligand |
| How does a "general" use pesticide differ from a "restricted" use pesticide | Restricted - generally causing undesirable effects on the environment, applicator, or workers. Can only be purchased by state licensed individuals General - causes no unreasonable, adverse effects when used according to the label. Can be purchased and applied by anyone. |
| Chlorinated hydrocarbons are _____ and cause acute effects by interfering with the transmission of _____ | Neurotoxicants; nerve impulses |
| Published by Rachel Carson in Silent Spring, this pesticide was identified as a neurotoxicant that interferes with the transmission of nerve impulses | DDT Note: insecticide |
| How do organophosphorus (OP) insecticides exert their toxicity? | Via inhibition of acetylcholinesterase Note: principle site of action is the PNS |
| Carbamates share a similar mode of action to OPs, inhibiting acetylcholinesterase. What is a notable difference between carbamates and OP insecticides? | Carbamates are more rapidly reversed than OP compounds |
| Pyrethroid Insecticides | Affect nerve membranes by modifying the sodium and potassium channels, resulting in depolarization of the membranes. |
| Herbicides | The most widely used class of pesticides e.g. TCDD aka Agent Orange |
| Fungicides | Relatively nontoxic Note: Hydrolyze to produce known carcinogens such as ethylenethiourea (ETU) |
| Examples of food additives and containinants | Antioxidants, fungistatic agents, emulsifiers, stabilizers, humectants, dyes, vitamins, amino acids, inorganics, chelating agents |
| Microbial toxins | toxic substances produced by microorganisms that are of high molecular weight and have antigenic properties e.g. Clostridium tetani (tetanus), C. botulinum (botulinum) Note: toxic compounds produced by bacteria that do not fit these criteria are referred to as poisons |
| Mycotoxins | Ergot alkaloids consist of three groups: ergotamine, dihydroergotamine, and ergonovine. Affect the nervous system and induce vasoconstriction Aflatoxins undergo hepatic metabolism to form reactive epoxide intermediate |
| Algal toxins | Represent the array chemicals derived from cyanobacteria, dinoflagellates, and diatoms |
| Plant toxins (phytotoxins) | Common drugs of abuse (e.g. cocaine, caffeine, nicotine) and components of food (e.g. safrole found in black pepper) |
| Animal toxins | Actively Venomous - injecting poisons through specially adapted strings or mouthparts Passively Venomous - inadvertent ingestion |
| Solvents | Common classes: Aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, aliphatic alcohols, glycols and glycol ethers, and aromatic hydrocarbons |
| Drugs of abuse | either have no medicinal function or are taken at dose levels higher than would be required for therapy |
| Combustion products | polycyclic aromatic hydrocarbons (PAHs) are the most widely studied for aspects of chemical carcinogenesis |
| Cosmetics | Little risk of systemic poisoning. Most common deleterious effects are allergic reactions and contact dermatitis. |
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