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48 Cards in this Set
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Toxic metals include:
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-heavy metals (e.g., lead, mercury, nickel, cadmium)
-other metallic compounds (e.g, aluminum, iron, tin) -Featured in the CERCLA priority list of hazardous substances |
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CERCLA Priority list of Hazardous substances
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-The agency for toxic substances and disease registry (ATSDR) has identified a list of ranking ordered hazardous substances, known as the CERCLA priority list of Hazardous Substances.
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The list is revised and published on a 2 year basis, with a yearly informal review and revision
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Characteristics of Hazardous substances on the CERCLA priority list
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-Pose the most significant potential threat to human health because thy have
-frequency of occurrence at NPL sites -known or suspected toxicity and -potential for human exposure at NPL sites -it is possible for substances with low toxicity but high NPL frequency of occurrence and exposure to be on the priority list. |
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Top 20 hazardous substances from the 2011 CERCLA Priority list of Hazardous Substances
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1. arsenic
2. lead 3. mercury 4. vinyl chloride 5.polychlorinated biphenyls 6. benzene 7. cadmium 8. Benzo(a)pyrene 9. Polycyclic aromatic hydrocarbons 10. Benzo(b)fluoranthene 11. chloroform 12.arclor 1260 13. DDT 14. Arclor 1254 15. Dibenzo (a, h) anthracene 16. Ticholoethylene 17. Chromium, hexavalent 18. Dieldrin 19. phosphorus, white 20. Chlordane |
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National Prorities List (NPL)
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-This is "EPA's list of the most serious uncontrolled or abandoned hazardous waste sites in the United States identified for possible long-term remedial action under Superfund."
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sites are scored basedon the Hazard ranking system and updated at least once a year.
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Heavy metals
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-A heavy metal has a high atomic weight with a specific gravity that exceeds the specfic gravity of water by five or more times.
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Classification of toxic effects of metals
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1-Major toxic metals with multiple effects
2-essential metals with potential for toxicity 3-metals related to medical therapy 4-minor toxic metals |
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1. major toxic metals with multiple effects
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Arsenic (As)
Beryllium (Be) Cadmium (Cd) Chromium (Cr) Lead (Pb) Mercury (Hg) Nickel (Ni) |
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Bioaccumulation
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Toxic substances such as heavy metals become more concentrated and potentially more hamful as they move up the food chain
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modes of exposure
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-lungs (through inhalation of dusts, metal fumes, and vapors)
-skin (through contact with dusts) -Mouth (by ingestion) |
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High and low level contacts
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contact with high concentrations of toxic metals is most likely to occur in an occupational setting, e.g., among persons who work with metals
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lower level exposures may result from contact with the ambient environment (e.g., children may ingest toxic metals present in paint).
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Acute toxic metal poisoning
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The symptoms of acute poisoning from exposure to metals generally have rapid onset-from a few minutes to approximately one hour
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Symptoms of acute poisoning from toxic metals
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-depending upon portal of entry, symptoms may consist of gastrointestinal effects (vomiting and stomach pain) and neurological effects (headaches, suppression of normal breathing, and convulsions)
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Symptoms of long-term exposure at lower levels
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difficult to differentiate fomr those of chronic medical conditions
-reduced cognitive fucntioning (e.g., learning impairment) |
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Potential exposure media
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-air
-soil/dust -water -biota/food |
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Gender differences and heavy metal exposure effects
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-The health effects of exposure to heavy metals (e.g. nickel, cadmium, lead and mercury) are different for women then they are for men.
-These differences have been aattibuted to hormonal and metabolic processes related to menstruation, pregnancy and menopause. |
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Fetuses, infants, and children and exposure to heavy metals
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For these groups, heavy metals are known to present serious hazards, which can include:
-impairment of physical and mental development -damage to internal organs and the nervous system -some forms of cancer -mortality |
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Children and Exposure to heavy metals
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nervous system damage:
-memory impairment -difficulty in learning -range of behavioral problems, such as hyperactivity syndrome and overt aggressiveness |
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heavy metal exposure among children versus adults
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Because a child's body weight is smaller than that of adults, children consume more food in proportion to their body weight and consequently receive higher doses of heavy metals that my be present in their food.
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Fetal exposure effects
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lead and mercury have the capacity to cross the placental barrier, causing potential fetal brain damage
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Major toxic metal with multiple effects
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-Arsenic
-beryllium -Cadmium -Chromium -Mercury -Lead -Nickel |
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Arsenic
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Varies in toxicity depending upon its chemical forms
-byproduct of refining gold and other metals -used in pesticides, wood preservatives and in manufacturing processes -exposure can come from ingestion and inhalation |
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Standards for Arsenic
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In 2001, the EPA announced the standard of 10 mg of arsenic per liter of drinking water, with the yera 2006 set as the compliance date for this standard.
this standard has been lowered from 50 mg of arsenic per liter of water |
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Potential health effects of arsenic exposure
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-skin, bladder, kidney, and liver cancer when ingested
-lung cancer when inhaled -peripheral vascular disease -cerbrovascular disease -CVD, hypertensive heart disease -Diabetes -Adverse pregnancy outcomes--spontaneous abortions, still births, and perterm births |
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Beryllium
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used widely in industry because of its special properties (lighter than aluminum, stronger than steel)
-employeers in the metal processing industry are most likely to be exposed -inhalation one of the most common methods of exposure -class A carcinogen |
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Cadmium and the general population
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-primary sources of cadmium exposure for the general population are cigarette smoke and dietary cadmium
-cadmium bioaccumulates in shellfish and is found in some species of mushrooms |
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Occupational exposures to cadmium
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comes from production of nickel cadmium batteries, zinc smelting, manufacture of paint pigments, soldering, and from employment in metal factories
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Effects of cadmium exposure
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-osteoporosis in women, height loss in men,
kidney damage, elevated blood pressure, cardiovascular dieseases, 'ltai-ltai"disease |
ltai-ltai disease- hunched over picture
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Chromium
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Naturally occurring element in the earth's crust (e.g., rocks, soils and materials of volcanic origin)
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most common forms:
Chromium (0) Chromium (III) essential ingredient Chromium (VI) classified as a carcinogen |
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Effects of Hexavalent Chromium (Cr VI) exposure
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-digestive problems and damage to the organs such as the kidney and liver when ingested
-produces skin ulcers when applied to skin -inhalaing chromium (VI) in high concentrations may cause respiratory problems, for examples nose bleeds, perforation of the nasal septum and runny nose |
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Erin Brockovich
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Advocated for residents of Hinkley, CA against a power company accused of polluting the town's water with chromium (VI)
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Mercury (Hg)
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Naturally occurring metal that is highly toxic
-released into the environment as a by-product of industrial processes |
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Mercury deposition in lakes and rivers
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even at low levels, mercury deposited in bodies of water represents a potential hazard to human health
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Methylation-microorganisms convert elemental mercury into methyl mercury.
-the process of bioaccumulation causes Mercury level to become more concentrated in aquatic invertebrates |
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Legacy of Mercury Contamination
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minamata disease
-water contamination around the new almaden mine in California |
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Lead (Pb)
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Sources of environmental lead include leaded gasoline, tap water from soldered pipes, and painted surfaces in older buildings
-another common source of household lead exposure is imported pottery that is used in food service. |
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Lead exposure
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-serious central nervous system effects and other adverse health consequences occur even when ingested at low levels
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lead poisoning is one of the most common environmental pediatric health problems in the U.S.
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Nickel (Ni)
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Classified as a heavy metal, nickel is one of the constituents of the earth's crust
-human exposure to low levels of nickel is probably universal and unavoidable -Employed in the production of many of the appliances and tools that are used in everyday life, such as nickel cadmium batteries |
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Effects of nickel exposure
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one of the most common reactions to skin contact with nickel is nickel allergy, manifested as contact dermatitis.
-Cardiovascular-related and renal diseases as well as fibrosis of the lungs -potential carcinogenic action |
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Essential metals with potential for toxicity
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Copper, zinc, and iron are essential for human nutrition but can be toxic if ingested in excessive amounts
-an optimal range of these essential metals is necessary to maintain health. |
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Copper (Cu) and the Environment
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Copper appears in electrical wires, pipes, in combination with other metals to form alloys, as a mildew inhibitor and as a wood and leather preservative.
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The ATSDR estimates that in the year 2000 alone, approx. 1.4 billion lbs of cooper were released into the environment during industrial processing
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Effects of copper exposure
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concentrated amounts (far above trace levels) can produce respiratory and gastrointestinal disturbances
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Respiratory effects form copper dust include irritation of the respiratory tract (e.g., nose and mouth)
-very high levels are known to cause liver damage, renal damage and death. |
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Exposure to copper
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occurs by inhalation, ingestion of copper containing foods and water and direct contact with skin.
small amounts may dissolve into tap water from copper piping, causing copper levels to become more concentrated when the water remains in the pipes overnight. |
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Zinc (Zn)
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a frequently occuring element found in the earth's crust, zinc permeates air, soil water and to some degree all foods.
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used commercially as a coating for rust inhibition, as a component of batteries, and in combination with other metals to make brass bronze and other alloys
a nutritional element that is important for maintaining health |
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Negative effects of excessive amounts of Zinc
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consumption of large quantitites is associated with gastrointestinal problems such as stomach cramps, nausea, and vomiting
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Zinc can also cause enemia and damage to the pancreas
Breathing high concentrations of zine in the workplace causes a disease known as metal fume fever, This condition appears to be an immune-mediated response that originates in the lungs |
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Iron (Fe)
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one of the most ubiqitous metals in the earth's crust
-vital to human health, iron is important to the growth of cells and the transport of oxygen within the circulatory system. |
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Iron toxicity
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acute iron intoxication (accidental poisoning) is amoing the most common childhood poisonings
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other groups at risk from iron overload (iron toxicity) include adult men and post menopausal women.
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metals used in medical therapies
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aluminum
bismuth (Bi) (heartburn, upset stomach) Gold (Au)-Arthritis lithium-bipolar disease |
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Aluminum
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This silver white metal is used widely in food and beverage containers, in pots and pans and in construction sites.
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An ingredient in various medicines and cosmestics. for example, buffered aspirin and antiperspirants
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