Water Pollution

Question 1

Any physical, biological, or chemical change in water quality that adverselyaffects living organisms or makes water unsuitable for desired uses.

Answer 1

water pollution

Question 2

The most serious water pollutants in terms of human health worldwide

Answer 2

pathogenic organisms

Question 3

The main source of these pathogens is

Answer 3

untreated or improperly treated human wastes

Question 4

The WHO estimates that ______________ of all
sickness and disease in less-developed countries can be attributed to waterborne infectious agents and inadequate sanitation

Answer 4

80%

Question 5

The amount of oxygen dissolved in water is a good indicator of water quality and of the kinds of life it will support.

Answer 5

oxygen level

Question 6

Water with an oxygen content of ________ will support game and other desirable forms of aquatic life.

Answer 6

6 ppm

Question 7

Water with less than _____ oxygen will support mainly worms, bacteria, fungi, and other detritus feeders and decomposers.

Answer 7

2 ppm

Question 8

Oxygen is removed from water by ____________ and chemical processes that consume oxygen

Answer 8

respiration

Question 9

is the amount of dissolved oxygen that must be present in water in order for microorganisms to decompose the organic matter in the water, thus a useful test for the presence of organic waste in water

Answer 9

biochemical oxygen demand (bod)

Question 10

uses a strong oxidizing agent (dichromate ion in 50% sulfuric acid) to completely breakdown all organic matter in a water sample.

Answer 10

chemical oxygen demand (cod)

Question 11

the oxygen decline downstream.

Answer 11

oxygen sag

Question 12

• Further downstream, the water may become so oxygen-depleted that only the most resistant microorganisms and invertebrates can survive.

Answer 12

dead zone

Question 13

rivers and lakes that have clear water and low biological productivity.

Answer 13

oligotrophic

Question 14

waters that are rich in organisms and organic materials. Eutrophication is an increase in nutrient levels and biological productivity.

Answer 14

eutrophic

Question 15

Some toxic inorganic chemicals are released from rocks by ____________, are carried by runoff into lakes or rivers, or percolate into groundwater aquifers.

Answer 15

weathering

Question 16

Some soils contain naturally high concentrations of soluble salts, including toxic selenium and arsenic.

Answer 16

nonmetallic salts

Question 17

Salts, such as _________-, that are non-toxic at low concentrations also can be mobilized by irrigation and concentrated by evaporation, reaching levels that are toxic for many plants and animals.

Answer 17

sodium chloride

Question 18

Globally, 20% of the world’s irrigated farmland is estimated to be affected by __________

Answer 18

salinization

Question 19

Acids are released as by-products of industrial processes, such as leather tanning, metal smelting and plating, petroleum distillation ,and organic chemical synthesis

Answer 19

acids and bases

Question 20

is an especially important source of acid water pollution.

Answer 20

coal mining

Question 21

due to acid precipitation has been reported in about 200lakes in the Adirondack Mountains of New York State and in several
thousand lakes in eastern Quebec, Canada.

Answer 21

aquatic damage

Question 22

Include drugs, pesticides, and other industrial substances

Answer 22

organic pollutants

Question 23

from shipwrecks and well blowouts, such as the 2010explosionofthe Deepwater Horizon in the Gulf of Mexico, can be disastrous for ecosystems and local economies.

Answer 23

oil spills

Question 24

Erosion and runoff from croplands contribute about 25 billion metric tons of soil, sediment, and suspended solids to world surface waters each year

Answer 24

sediments

Question 25

Raising or lowering water temperatures from normal levels can adversely affect water quality and aquatic life

Answer 25

thermal pollution

Question 26

The cheapest and most effective way to reduce pollution is usually to avoid producing it or releasing it to the environment in the first place.

Answer 26

source reduction

Question 27

The first step in municipal waste treatment. It physically separates large solids from the waste stream

Answer 27

primary treatment

Question 28

Consists of biological degradation of dissolved organic compounds. The effluent from primary treatment flows into a trickling filter bed, an aeration tank, or a sewage lagoon

Answer 28

secondary treatment

Question 29

a hybrid between a traditional septic tank andafull sewer system. A tank near each dwelling collects and digests solid waste just like a septic system. Rather that using a drain field, however, dispose of liquids effluents are pumped to a central treatment plant.

Answer 29

effluent sewerage

Question 30

can cut secondary treatment cost to one-third of mechanical treatment costs, or less. Effluent from these operations can be used to irrigate crops or even raise fish for human consumption if care is taken to first destroy pathogens

Answer 30

constructed wetlands

Question 31

There are two basic methods used to purify water of dissolved minerals:

Answer 31

filtration and distillation

Question 32

means finding remedies for problems. New developments in environmental engineering are providing promising solutions to many water pollution problems

Answer 32

remediation

Question 33

confine or restrain dirty water or liquid in situ or cap the surface with an impermeable layer to divert surface water or groundwater away from the site and to prevent further pollution.

Answer 33

containment methods

Question 34

pump out polluted water so it can be treated. Manypollutants can be destroyed or detoxified by chemical reactions that oxidize,reduce, neutralize, hydrolyze, precipitate, or otherwise change their chemical composition.

Answer 34

extraction techniques

Question 35

living organisms used effectively and inexpensively to clean contaminated water. This can be carried out in tanks or troughs

Answer 35

bioremediation