Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
What is distillation?
|
Vaporizing water and condensing the pure vapors, as in the water cycle, has been used by people as a water purification means.
Distilled water is among the purest forms of water available. |
|
|
What is transpiration?
|
the loss of water vapor from the leaves of plants.
|
|
|
What is eutrophication?
|
The term for this unappealing process in which over fertilization of a body of water affects its matter cycles, with these consequent changes in the ecosystem, is eutrophication.
|
|
|
What is the most important purifying step in the water cycle? How does it work?
|
A key step in the water cycle is evaporation. Water in the ocean or other bodies of water absorbs solar energy, enabling water molecules to escape into the gas phase.
|
|
|
What is an aquifer?
|
Groundwater accumulations can move slowly like great underground rivers through porous layers called aquifers.
|
|
|
What is groundwater?
|
Some infiltrating water is held in the soil, and some is pulled downward by gravity, percolating through the soil and gravelly subsoil until it reaches an impervious layer of rock or dense clay, where it accumulates, becoming groundwater.
|
|
|
Why does groundwater usually contain few organic contaminants (what is its natural purification mechanism?)
|
In the process of percolation, microorganisms and particulate impurities are filtered out, giving clear, purified water. Dissolved materials like ionic compounds, however, are not removed through percolation. Groundwater instead is more likely to pick up an increased concentration of dissolved ionic materials from the soil with which it comes into contact.
|
|
|
Why does groundwater usually contain dissolved inorganic compounds?
|
Groundwater is more likely to pick up an increased concentration of dissolved ionic (inorganic) materials from the soil with which it comes into contact.
|
|
|
Is hard water hazardous to your health? What is hard water?
|
No, there is no health issue. Dissolved calcium, magnesium, and iron ions are common in groundwater; water containing any or all of these dissolved minerals is called hard water. These elements are all required to some degree by our bodies and represent no danger to our health.
|
|
|
How can a household's choice of laundry detergent affect eutrophication of a nearby lake?
|
In many aquatic ecosystems phosphate is the limiting nutrient, the one in shortest supply for promoting plant growth. Which is most important for a given body of water will depend on the nature of the area from which it receives its runoff. It is significant to note, then, that about sixty percent of the phosphate in waste water is from detergents.
|
|
|
In which type of water supply do you think nutrient runoff could lead to the most serious causes of eutrophication?
a) Ocean b) fast-flowing river c) small pond |
A small pond because of the lack of water flow (stagnant). Phytoplankton has a high turnover rate, meaning that its increased growth rate is balanced by an accelerated die off, with a resulting accumulation of dead material throughout the system.
|
|
|
All these compounds have been implicated as carcinogens that can appear in a water supply: carbon tetrachloride,
In the compound above, what functional group do they all have in common? |
Alkyl halide C- Cl
|
|
|
What is Giardia lambia, and what is its effect on public health?
|
Giardia lambia are one-celled animals (Protozoans) (; parasitic protozoans like Giardia need a host like the human gut in which to replicate. In the U.S., from about 1.5% to 20% of the population may carry Giardia, though most may show no clinical symptoms. Symptoms usually appear 1 to 4 weeks after infection, and include diarrhea, weight loss, and chronic fatigue. If untreated, Giardia and its accompanying symptoms can last for months and even years.
|
|
|
Why is chlorination an important step in water treatment?
|
Without chlorination to disinfect the water supply, we would be subject to plagues of disease caused by infectious microorganisms. About 80% of the U.S. population drinks chlorinated water.
|
|
|
Why is filtration an important step in water filtration?
|
Filtration, before chlorination, results in a relatively small increase in chloroform levels. This important insight into the mechanism of chloroform formation is useful and prevents carcinogen accumulation in the drinking water
|
|
|
Is lead usually present at high levels in ground water? in surface water?
|
Lead concentrations in surface water are usually low, ranging 1 to 10 parts per billion gallons.
The first water drawn in the morning from plumbing systems that contain lead should never be used as drinking or cooking water. |
|
|
How does lead enter the drinking water supply?
|
Lead is most likely to dissolve from pipes and when the water is soft and acidic; newly solder is more likely to leach lead than old solder. For that reason, the first water drawn in the morning from plumbing systems that contain lead should never be used as drinking or cooking water.
|
|
|
What can a community water supplier do reduce lead content in tap water?
|
Current EPA regulations allow communities up to 20 years to comply with lead standards by removing old pipes. First, communities may attempt to lower lead levels in water by adding basic materials like sodium bicarbonate and lime to neutralize the acidity of the water.
|
|
|
What can a home owner do to reduce lead in tap water?
|
adding basic materials like sodium bicarbonate and lime to neutralize the acidity of the water.
|
|
|
What are the conditions necessary for the action of aerobic bacteria?
|
Presence of organic matter (dead plants and plankton) and oxygen.
|
|
|
Name some products of decomposition by anaerobic bacteria.
|
Nitrogen compounds, instead of being oxidized to nitrates, form ammonia instead. Sulfur compounds, instead of being oxidized to sulfates, form hydrogen sulfide, the compound responsible for the odor of rotten eggs. The term for this unappealing process in which over fertilization of a body of water affects its matter cycles, with these consequent changes in the ecosystem, is eutrophication.
|
