Lectures 16-18 + TBL 5 Flashcards
1
Q
Bulk solids covering the bottom of rivers, lakes and oceans
A
Sediments
2
Q
Sediments consist of (5)
A
- clay, 2. silt, 3. sand, 4, organic matter, 5. other biogenic matter
3
Q
Small particles between dissolved and particulate matter such as clays and bacteria
A
colloids
4
Q
The finer the particle size, the more ______ the water, and the less likely it is to _______
A
active, settle
5
Q
Sediments act as a repository of ____, ____ and _____ detritus
A
biological, chemical, pollutant
6
Q
Water that is held in microscopic pores within sediments
A
pore water
7
Q
detrital matter and rock break-down products wash into the water
A
weathering
8
Q
initiated by pH changes, redox, or microbial activity
A
precipitation reactions
9
Q
a hydroxyapatite precipitate is formed when ____ rich wastewater enters water with high ______
A
phosphate, calcium
10
Q
____ _____ precipitates form when water rich in _____ and calcium loses CO2 (g)
A
calcium carbonate, CO3
11
Q
When Fe is oxidized to ____ and ______, a hydroxide (______) precipitates
A
Fe2+, Fe3+, Fe(OH)3
12
Q
Some bacteria use ____ as an electron receptor, while others reduce Fe(OH)3 to _____. Together, this leads to a precipitate forming _____
A
SO4, Fe2+, FeS
13
Q
Organic matter and other _____ _____ materials are delivered to sediments if not _____ in the water column
A
particulate biogenic, decomposed
14
Q
Sediments form in 3 different ways
A
- weathering, 2. precipitation reactions, 3. biological processes
15
Q
Organic compounds interact strongly with ______, similar to organic compounds bound to ______. ____ organic compounds (on surfaces) biodegrade or undergo chemical reactions at different _____ than free organic compounds, meaning they have low ______ ____.
A
sediments, colloids, sorbed, rates, biological activity
16
Q
A measure of how many cations can stick to a particle
A
cation exchange capacity
17
Q
Organic matter complexes with ____ ___ and ____ _____, as they also have a cation exchange capacity
A
clay minerals, humic substances
18
Q
_________ organic compounds are very mobile in pore waters, and most sediments lack ______. They have high ______ resulting in less ______.
A
anionic, anion exchange capacity, biological activity, sticking
19
Q
water _____ organic compounds are strongly bound by ______ _____ (______)
A
insoluble, humic substances (lipophilic)
20
Q
3 properties of colloidal particles
A
- extremely small particles between 1nm-1um. 2. scatter light, 3. intermediate properties between solution and suspended matter
21
Q
When the particle size range is the same as the wavelength of light, light is scattered off the surface of the particles instead of being transmitted through them
A
tyndall effect
22
Q
A larger number of _____ particles has a greater surface area than a large particle of the same total _____, which gives more surface area for interacting with ____ in solution
A
small, volume, ions
23
Q
Most of the atoms as a percentage are in the ______, existing as _____ particles. As particle size grows, less of them are at the surface
A
surface, small
24
Q
Colloids in solution are stabilized by ____ and ____ ____
A
hydration, surface charges
25
When colloids ______, they are bigger and more influenced by ____, thus they stop being colloids
aggregate, gravity
26
A layer of water on the surface of the colloid which keeps it from contacting other colloids and forming larger units
Hydration
27
Colloids of like charge repel one another
surface charge
28
Surface charge of colloids is ____ and ____ ____ dependent. Most colloids and other surfaces in neutral water are ____ charged. When a cation is stuck to the colloid, the colloid is _____. When a cation is not stuck to the colloid it is ______ _____.
pH, ionic strength, negatively, neutral, negatively charged
29
The total number of ions in solution
ionic strength
30
Colloids that strongly interact with water (ex. proteins, synthetic polymers)
large molecules / ions
31
consist of aggregates of ions and molecules called micelles, which have a hydrophilic head and hydrophobic tail, resulting in clusters in which the tails point inward and the heads point outward. (eg. sodium stearate, soap)
association colloids
32
colloids with charged surfaces, surrounded by counter-ions in solution, leading to the electric double layer
clay minerals
33
The condensed layer close to the surface where ions of opposite charge become "fixed" to the surface
stern layer
34
the diffuse layer in the surrounding solution where ions in motion have adjusted to the surface charge
guoy-chapman layer
35
beyond the ___ ___ the bulk solution is unaffected by the _______
double layer, surface
36
3 ways in which surface charges can be generated
1. chemical reaction at particle surface, 2. ion adsorption, 3. ion replacement
37
Chemical reactions at the particle surface generally involve gain/loss of ______ which means it is ____ dependent.
H+, pH
38
Ion adsorption involves attachment of ions onto the colloid surface, but not by ______ bonding. It involves _____ bonding or ____ _____. In other words, they are organic ______ on oxide surfaces
covalent, hydrogen, van der waals, coatings
39
ion replacement involves the replacement of normal _____ constituent in a mineral by an ion of different ______ state. (ex. Si4+ replaced by Al3+)
lattice, oxidation
40
when small particles come together, form bigger particles and settle out
aggregation
41
Involves reduction of electrostatic repulsion
coagulation
42
involves bridging compounds and/or chemical bonds between colloids
flocculation
43
Colloidal particles are normally prevented from ______ by electrostatic _____ of the electric double layer
aggregating, repulsion
44
weak attractive forces between molecules that are minor in small molecules but a major force in colloids (additive)
van der waals forces
45
forces contributing to van der waals forces (4)
1. dipole-dipole, 2. dipole-induced dipole, 3. induced dipole-indued dipole, 4. instantaneous dipole
46
Particles interact through their ____ ____ in solution. Like _____ charges between colloids repel each other. As the distance from the surface of particles increases, ____ _____ decreases. Aggregation occurs when _____ forces are larger than _____ forces.
double layers, negative, electric potential, attractive, repulsive
47
Colloids do not repel each other until the double layers ______, because there is enough ___ ____ between them that is not influenced by the surface
overlap, bulk solution
48
The addition of _____ coagulates colloids. This is because the increased _____ ______, which decreases the _____ _____.
ions, ionic strength, electrostatic repulsion
49
With low ionic strengths, the ______ is felt before the attraction, because it takes many molecules to _____ the charge. This results in a very wide ____ ______, and molecules are less likely to _______
repulsion, neutralize, double layer, stick
50
With medium ion concentrations, the repulsion is still felt before the attraction. However, in high ion concentrations, the _______ is felt before the _____, making particles likely to aggregate.
attraction, repulsion
51
With low ionic strength, there is a net repulsion until the particles are very ______, and must overcome a high activation energy to aggregate. At high ionic strength, there is only a net _____, and no ____ ____, making particles very likely to aggregate
close, attraction, activation energy
52
high molecular weight polymers with ionizable functional groups. Bind to two (or more) colloids causing them to flocculate
polyelectrolytes
53
The most common functional groups on a polyelectrolyte are
SO3-, CO2-, NH3+
54
cationic polyelectrolytes can flocculate _____ colloids by binding and forming a _____ with the colloid charges. Anionic polyelectrolytes bridge with a ______, and this binds to the colloid
negative, bridge, metal
55
The main objective of biological waste treatment is the removal of ________, mostly due to _______
BOD, dissolved organic C (DOC)
56
______ are used to produce biomass in waste treatment. Some DOC is converted to ____ and removed as a gas. Some DOC is converted to ______ biomass and removed as _______, through ___ _____. This can be enhanced by adding polyelectrolytes
microorganisms, CO2, bacterial, floc, chemical bridging
57
aggregated bacteria cells
floc
58
Not all neutral species are _______, and small amounts can be ______., such as _____ complexes, or _____ pairs
solids, dissolved, hydrated, ion
59
the amount of an ionic solid that goes into solution as the neutral form of the salt (NOT dissociated into ions)
intrinsic solubility
60
Total solubility =?
intrinsic solubility + ksp contribution(half the ksp) (both that which goes into solution intact and that which goes into solution by separating into ions
61
These pollutants are toxic and harmful to aquatic biota
inorganic pollutants, trace elements/heavy metals, pesticides
62
These pollutants are toxic
radionuclides, organic pollutants
63
This pollutant is harmful to human health
asbestos
64
These pollutants can cause eutrophication
nutrients, detergents
65
This causes metal transport
organic ligands
66
these pollutants affect water quality and aquatic biota
salinity, acidity, suspended sediments
67
These pollutants affect water quality and oxygen levels
sewage, BOD
68
7 main sources of water pollution
sewage, mining (AR), industrial waste, fertilizer runoff, pesticides, garbage, oil leaks/spills
69
elements or other chemical compounds which exist at very low levels in a given system (ie. < ppm)
trace substance
70
refers to elements at very low levels
trace element
71
Some elements such as ___, ____ and ____ are extremely toxic even at trace levels, because they attack ____ bonds in enzymes and bind ______. Some metalloids such as _____, ____ and ____< are also important pollutants. Some trace elements are essential _____ at low levels, but toxic at high concentrations, such as _____ and _____
Cd, Pb, Hg, S, proteins, As, Se, Sb, nutrients, Se, Cu
72
metals that interact with plankton and are essential elements at low concentrations, but can but toxic in high concentrations
biologically active metals
73
For a non-essential element, there is no ____ effects, and increasing concentration just makes it more _____. For essential elements, there is a _____ stage at low concentrations, an ____ stage a medium concentrations, and as concentrations increased above the required level, the element becomes ______
beneficial, toxic, limiting, optimal, toxic
74
Cadmium occurs in the ____ oxidation state and undergoes no redox changes. It's main sources are from ____ and ____ , of reduced sediments, (ie. dredging of harbours) metal ______ (industrial wastes), and runoff from ______ and ______. In aerobic conditions, it forms a soluble ______ complex, while in anaerobic conditions, it precipitates as an insoluble _______. It results in severe _____ effects, such as _______ and _____ (itai-itai disease). Cadmium can replace ____ in some enzymes and has similar chemistry to it
2+, mining, aeration, plating, pesticides, fertilizers, CdClx(2-x), CdS, poisoning, brittle bones, kidney failure, Zn
75
Lead occurs in a _____ oxidation state in water and undergoes no redox changes. Its main sources are from _____ and ____ operations, natural _______, _______ (leaded gasoline), and _______ and _______ (in old buildings). Acute lead poisoning results in _____ _____ and _____ dysfunction as well as ______. It is particularly harmful to children as it can cause _________
2+, industrial, mining, minerals, fuels, lead pipes, paints, kidney, liver, brain, death, mental retardation
76
Mercury is the heavy metal of most concern. It is a trace component of many ______ (ie. HgS), is released from _____, _____, and ______, _______, _______, etc. Although liquid Hg is not very hazardous, the ______ is, as it can be absorbed through the skin. Bacteria in water can form _______ species, which is the most ______ and ______. ______ is also volatile. It is concentrated in biological systems (_______). _____ _____ results when people ingest contaminated ______ or drink water containing soluble species. When mercury ______ in aquatic environments, it can be carried to remote regions through the _______
minerals, broken batteries, thermometers, lawn fungicides, amalgam tooth fillings, pharmaceuticals, vapour, methylated, soluble, toxic, dimethyl mercury, biomagnified, minamata disease, fish, cycles, atmosphere
77
The sources of Arsenic are _____ minerals, ____ _____, combustion of ____ ____ (via atmosphere), and ______ (in past). Acute poisoning results from ingestion of _____mg, and chronic poisoning from long term exposure can result in _______. Bacteria and _____ convert As to a variety of forms. _____ is more toxic, while ________ is less toxic
phosphate, mine tailings, fossil fuels, pesticides, 100, death, plankton, arsenite (AsO3), methylated forms
78
Complexation / chelation of metals by organic ligands typically _____, which leads to less free ion, but more total ion in solution
increases their concentration in water, decreases metal bioavailability
79
Metals are bound to organic ligands through _____ ______, bridging between O, S, or N between metal and carbon (not a M-C bond). The degree of complexation is a function of ______ and _______ (ie. ML + 2H+ --> M2+ + H2L)
functional groups, pH, concentration
80
Bioaccumulation often leads to ______ as the substance is not _____ as fast as it is _____
biomagnification, released, taken up
81
With ______ ligands, cells are able to thrive and do better up to a higher ______, because there is more metal bound (more mobile cells)
stronger, [free metal]
82
Toxicity corresponds to _____ not ______.
[free metal] total Cu
83
In the _____ _____, there are strong Cu-binding ligands, which lower the free concentration of copper, and makes it almost ______ complexed. The free Cu concentration in the surface is ______, while in the deep is ________
upper ocean, 100%, 10^-13, 10-^-10
84
_______ such as ______ make ligands to _____ their environment. In the ____ ____, organisms show a toxic response at a _______, while in the _______, there is a response at higher levels. In lab, when ____ is added slowly, ligands are produced
phytoplankton, synechococcus, detoxify, open ocean, lower [Cu2+], coast, Cu
85
Complexes that are bound by a metal-carbon bond. They do not dissociate at a lower pH or with dilution, and have a stronger association than complexation
organometallic complexes
86
Examples of organometallic complexes include _______ _____ groups such as ____ _____, or ______. Metal-carbon bonding can either increase or decrease the _____ of metals in aquatic ecosystems. ______ are usually involved in transformations
alkyl organic, methylated mercury, carbonyls, toxicity, microorganisms
87
_____ and _____ are likely carcinogenic, but _____ may be beneficial at low levels
Cd, As, Cd
88
As contamination in water occurs when As is released from ______. ______ particles are good at oxidizing organic matter, resulting in release of ____ and any As bound to the surface of _______.
particles, FeOOH, Fe2+, FeOOOH
89
It is still unclear where the organic matter that FeOOH oxidizes comes from, but a possibility is from the _______ ____ below the shallow ground water
clay layer
90
In order to combat poisoning, you could identify which wells are ______, develop low cost _______, install ____ ____ that draw from deep (below 200m) uncontaminated water, or harvest _____ instead (cleanest water)
contaminated, filters, tube wells, rainwater
91
The As poisoning resulted from the As in the ____ in Bangladesh. ____ ____ were contaminated, leading to cancer. _____ and _____ are both harmful, but the latter is coprecipitated and adsorbed on the surface of ______ in the sediments. In anoxic conditions, the insoluble ______ is reduced during the breakdown of organic carbon to ______, and at the same time, As is released and reduced to a more soluble _____. Thus, the solubility of As follows the solubility of ______.
bedrock, tube wells, As3+, As5+, FeOOH, FeOOH, Fe2+, As3+., FeOOH
92
water found underground in the cracks and spaces in soil, sand and rock
groundwater
93
Water containing As3+ can be treated by first oxidizing it to ______, and the reacting it with a solution in which ______ is added. This leads to the ______ precipitate. However, it is not a feasible solution in _______ pollution, and has no effect if clean water cannot get to individual homes
As5+, FeCl3, FeAsO4, widespread
94
Selenium comes from natural sources such as _____, and _____. It is essential at ____ levels but ___ at higher levels
soil, coal, higher, toxic
95
Copper mostly comes from ____ ____, ____ and ____ waste. It is essential at low levels but toxic at higher levels
metal plating, mining, industrial
