lecture 7 (3)- environmental hazard and health impact (toxic metals and elements)

16/10

how are metals man-made? __________ from smelters and coal-fired power plants, leaching from hazardous waste sites 

emissions 

what is the toxic metals and elements exposure? contaminated air, ________, water, occupational exposure, contact with _________ in occupations related to metal working

food, metals

metals are natural components of the Earth’s crust, they ___________ be degraded or destroyed. to a small extent, they enter our bodies via food, drinking water, and air

cannot

what are the dosage and effects of metals in our bodies? as trace elements, some heavy metals are __________ to maintain the metabolism of the human body. however, at higher concentrations, they may lead to ___________

essential, poisoning

what is the four category method for classifying metals? 
1. major ________ metals with ___________ effects

2. ________ metals with potential for _________

3. metals related to __________ therapy 

4. _________ toxic metals 

toxic, multiple, essential, toxicity, medical, minor 

what are some features of major toxic metals with multiple effects?
comprises the toxic heavy metals, toxic to life-forms and are not _________ to sustain life, toxic at ______ concentration, capacity of _____________ (more concentrated and harmful as they move ______ the food chain)

necessary, low, bioaccumulate, up

what are some features of essential metals with potential for toxicity? consists of metals that are considered to be __________ for life when present in trace amounts, however, concentrations greater than ______ amounts have the potential for toxicity

essential, trace

what are some features of metals related to medical therapy? metals used in medical therapy such as mood ____________ 

stabilization 

what are some features of minor toxic metals? toxicity generally is _________, they are ________ essential

lower, not

what is the definition of a heavy metal? any metallic chemical element that has a relatively _______ density and generally is _________ or poisonous at low concentrations

high, toxic

what is the criterion of “heavy”? has a high atomic weight with a specific gravity that exceeds the specific gravity of water by _________ or more times 

five 

many heavy metals are toxic to human health. what are some common heavy metals? _________, mercury, cadmium, and _______. indoor concentration is generally less than outdoor concentration, mainly produced by ______________ activities and deposit slowly in surrounding water and soil

lead, arsenic, industrial

what is arsenic? a common poison used for _________, used widely as __________ before the organic chemicals era.

acute poisoning: ingestion of 100 mg

chronic poisoning: common, low level in ___________ water and food

murder, pesticides, drinking

what are some sources of arsenic? pesticides, mining, __________ of iron and steel, combustion of coal, leachate from abandoned gold minds, used as a ________ preservative, tobacco ________, wallpaper paste and pigments in wallpaper 

production, wood, smoke 

what is the mode of entry of arsenic? __________, mostly through contaminated water and food. inhalation and skin _________ reported

ingestion, rarely

what are the health effects of arsenic? __________ defects, vascular disease, gastrointestinal damage, severe vomiting, diarrhea, death

birth

what is mercury? most volatile of all metals, it is the only common metal which is ___________ at ordinary temperatures, highly toxic in _________ form, liquid mercury itself is not highly toxic, and most of that is ingested is ____________ 

liquid, vapor, excreted 

what are the sources of mercury? elemental is employed in many applications due to unusual property of being a liquid that conducts ___________, large industrial operations, unregulated burning of _________ and fuel oil, emissions from mercury containing products (__________, thermometers)

electricity, coal, batteries

what is mercury mode of entry? ___________ (common), ingestion, absorption through skin (rarely reported)

inhalation

what are the health effects of mercury? dysfunctions of the central ___________ system, severe _________ damage, damage to cognitive skills, damage to kidneys, death

nervous, brain

what is lead? a bluish-white lustrous metal, very ________, highly malleable, ductile, and a relatively ________ conductor of electricity.

soft, poor

what are the sources of lead? lead industries (air and dust emissions), __________ emissions in some developing countries, piping, fixtures, leaching from __________ 

vehicle, landfills 

what are the modes of entry of lead? ingestion (usually through contaminated __________ and food), inhalation

water

what are the health effects of lead? effects the neurological and __________ systems, breaks the blood-brain barrier and interferes with the normal development of ________ in infants, observed to lower _____ levels in children, eventually result in death

reproductive, brain, IQ