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Pollution & Bioremediation > Midterm > Flashcards

Midterm Flashcards

1
Q

Number of chemicals in commerce?

A

85k-250k

Unclear true number since not all are admitted

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2
Q

What is an HPV?

A

High production volume chemicals

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3
Q

What is the number of HPVs?

A

3,000

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4
Q

How much HPV (percentage wise) have basic risk information? And what is the number of basic screening tests?

A

7%
43% are missing every test
57% have at least one test
There are 6 basic screening tests (called SIDs: screening information dataset)

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5
Q

How many people have water stress (pollutants) in their local rivers?

A

~ 5,000 mill

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6
Q

What are NAQs?

A

National air quality standards

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7
Q

How many Americans live in areas that exceed NAQs?

A

1/3rd

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8
Q

How many liters of air does a person inhale every day?

A

~11,000

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9
Q

How many people die every year due to pollution?

A

~9 mill

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10
Q

What is the GBD and how does pollution affect it?

A

Global burden of disease

Inc. due to pollution

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11
Q

What does the Lancet Commission (science reports) say about pollution?

A

Inc. GBD (connect multiple exposures to health effects)
It is not being dealt with
Vulnerable groups are disproportionately impacted
There are win-win solutions
Advocates usually skip over the necessary processes

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12
Q

What is the dilution paradigm?

A

Solution to pollution is dilution
It was a widespread belief
Ex. factories made tall stacks so smoke would be sent up and disperse in air (created acid rain)

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13
Q

What is the boomerang paradigm?

A

What is thrown away can come back and hurt you
Precautionary steps should be taken to stop any unknown longterm effects
Ex. Love canal

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14
Q

What is DDT?

A

Dichlorodiphenyltrichloroethane

Used in 1940s+ as first modern pesticide (opens sodium channels in insect neurons; caused hyperstimulation)

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15
Q

Problems with DDT?

A

Doesn’t break down
Soluble: can pass through membranes b/c it looks like cholesterol-based hormone
T1/2 is 2-15 years
Accumulates in fatty tissues
Metabolizes to DDE in liver (a reactive metabolite that is more toxic and impairs reproductive enzymes and reduces calcium)
DDT + congeners induce CYTP450 (oxidative stress)
Biomagnifies 10 mill-fold (trophic birds are high risk)

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16
Q

Benefits of DDT?

A

Used in WWII: the first war more people died from trauma than disease
Against malaria: dec from 1 mill cases to 9 in Taiwan over 24 years

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17
Q

What is biomagnification?

A

The increase of chemical concentrations through the foodchain

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18
Q

What is bioaccumulation?

A

The accumulation of a chemical concentration in ONE individual over their lifespan
From ALL external sources and ALL internal processes

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19
Q

What is the importance of “Silent Spring”?

A

Realization that humans alter the ecosystem and have long-term consequences through “invisible” technology
- Look at DDT, Agent Orange,, and Love Canal

Caused a policy change through a congressional hearing initiated by Kennedy

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20
Q

What does the general population use that affect pollution?

A

Disposing meds (most are tossed or flushed: 89.4%)
Organic wastewater contaminants (common are coprostanol, cholesterol, and caffeine)
PPCPs (pharmaceuticals & personal care products)
Endocrine disruptors (ex. artificial hormones) (highest concentration was detergent metabolites, then steroids and plasticizers)
Antibiotics
*These all are ‘pseudo’-persistent

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21
Q

What is ‘pseudo’-persistence?

A

chemicals that might break down easily, but are used on a daily basis so never leave the environment

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22
Q

What is a contaminant?

A

A substance that is present in greater than natural concentrations as a result of human activity

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23
Q

What is ecotoxicology?

A

(ecology + toxicology)
Definitions change over time; but are generally the same:
- Toxicology branch concerned with study of toxic effects, caused by natural & synthetic pollutants, to the constituents of the ecosystem (animals, vegetable, microbial)
- The study of poisons on individual organisms, to the ecological effects of pollutants

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24
Q

What is a pollutant?

A

A substance that occurs in the environment at least in part of human activity and which has a deleterious effect on living organisms

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25
Q

What is xenobiotic?

A

A foreign chemical not produced in nature and not considered a constitutive component of a biological system

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26
Q

What are the SCALES of an interdisciplinary field?

A

Molecules to ecosystems
Complexity of hierarchical scales
Learning adverse outcome pathways (toxicant to population response)

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27
Q

What are the SPECIALTIES of an interdisciplinary field?

A

Complexities of different specialities (different fields working together to determine outcomes)

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28
Q

List the organic legacy pollutants…

A

PAHs (Polycyclic aromatic hydrocarbons)
PCBs (polychlorinated biphenyls)
POP (Persistent organic pollutants) “dirty dozen”
Organophosphate insecticides

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29
Q

What are organic pollutants?

A

Contain carbon and at least 1 C-H covalent bond
Behavior dependent on the structure
Source is natural or anthropogenic

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30
Q

What are the characteristics of the C-H covalent bond?

A

Low polarity

Low water solubility

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31
Q

What are the basic characteristics of PAHs?

A

2+ fused benzene rings
Persistent (years -> decades)
Natural and anthropogenic (most common)
Have pyrolysis reactions (decomposes at high temps w/out O2)

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32
Q

Examples of natural sources of PAHs…

A

Volcanos
Fires
Natural oil seep

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33
Q

Examples of anthropogenic sources of PAHs…

A

Industry generators
Internal combustion engines
Grills
Offshore oil platforms

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34
Q

What happens to PAHs as their molecular weight increases?

A 
Dec. volatilization
Inc. bioaccumulation
Inc. absorption to particles
Dec. solubility (inc. Kow)
Inc. environmental persistence
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35
Q

What happens to PAHs released on land?

A

Evaporate

Penetrate soil -> metabolized by plants/soil invertebrates

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36
Q

What happens to PAHs released in water?

A

Evaporate
Float
Degradation by microbes
Metabolized by algae/zooplankton/fish…

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37
Q

How do PAHs affect thermoregulation of birds?

A

?

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38
Q

What are the ecotoxicological effects of PAHs?

A

Physical: smothering, reduced light
Habitat change: alter pH, dec. O2, dec. food availability
Toxicity: cellular membranes and enzyme-bound membranes

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39
Q

What are the properties of PCBs?

A 
Low water solubility (high in solvents & fats)
Low vapor pressure
High dielectric constant
High flashpoint
High thermal conductivity
Inert
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40
Q

What are the industrial uses of PCBs?

A

Used in transformers and capacitors

A coolant, lubricant, PVC in electrical wires, caulking sealant, and wood floor polish

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41
Q

How are PCBs different from PAHs?

A

PCBs are chlorinated

- It adds a charge to the chemical

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42
Q

How does chlorine affect PCBs?

A

More chlorine = more oily

Percentage of chlorine changes the properties

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43
Q

What happens to PCBs in the environment?

A

Persistent: resist breakdown (can take a century) and cycle between air, water, & soil
Transportable: absorb to particles so carried long distances (lighter compounds move further)
Accumulate: move up food chains in fatty tissues (a PBT)

44
Q

What is a PBT?

A

A Persistent Bioaccumulant Toxin

45
Q

List the characteristics of POPs…

A

Persist in environment
Bioaccumulate through food web
Pose risk of causing adverse effects to human health & environment

46
Q

What happened to the “dirty dozen”?

A

They were banned
12 POPs that were deemed unsafe
Ex. DDT

47
Q

What are organophosphate insecticides?

A

Initially developed as nerve gas agents
Inhibit acetylcholinesterase activity -> blocks acetylcholine metabolism
- Causes muscular rigidity & paralysis in insects
High water solubility
Low soil persistence
T1/2 = days to week (however, consistent use)

48
Q

Why are metals ubiquitous (everywhere)?

A

Because they are used in countless industries, commercial and consumer products
* They are the most common ubiquitous chemicals

49
Q

What is a unique property of metals?

A

They are elemental: they do NOT breakdown

50
Q

How would you treat acute metal toxicity?

A 
Using chelators (compounds that form complexes with metal ions)
Useless with chronic toxicity
51
Q

What is a problem with chelators?

A

Can bind to the wrong thing: there are many useful metals in the body that might be taken instead

52
Q

What are toxic mechanisms of metals?

A

Promoter of oxidation
Competition for divalent cation binding sites
Binding of sulfhydryl groups

53
Q

What are the sources of arsenic?

A

Industrial: from use in wood preservation & in microelectronics industry
Human environment: from fallout of smelters and arsenic pesticide spraying
Natural: Deep-water well water ingestion

54
Q

What are key exposure routes of pollutants?

A

Ingestion
Inhalation
Dermal contact

55
Q

What is the percentage of natural mercury sources? What are they from?

A

30-40%

Soil, ocean, geogenic, evapotranspiration, recycling

56
Q

What is mercury most used for?

A 
Small-scale gold mining (30%)
Chlor-Alkali (21%)
Batteries (18%)
Dental amalgam: cavity caps (8%)
Catalyst for vinyl chloride monomer... (8%)
57
Q

What is the cycle of mercury from coal burning to the environment?

A

Hg-S in coal ->
releases Hg^0 as vapor when burned -> lasts up to a year in atmosphere as Hg^0 ->
oxidizes to Hg^2+ ->
drops to ground ->
converts to MeHg via sulfate reducing bacteria (SRB) ->
Biomagnifies

58
Q

What does methylmercury do to the body (MeHg)?

A

A neurodevelopment threat (especially in pregnant women)
- Crosses membranes (including blood brain barrier & placenta)
- High affinity for protein thiols (multiple targets)
Bioaccumulates in muscles

59
Q

What is the movement of the neurotoxicity of MeHg due to continued exposure?

A

Molecular & neurochemical disruption ->

Sub-clinical neurophysiological impacts -> overt neurotoxicity & clinical “Minimata” disease

60
Q

What is the “Minimata” disease?

A

Minimata was the name of a Japanese town exposed to chemicals from a plant
Caused disease form MeHg

61
Q

What is a point source?

A

Any single identifiable source of pollution from which pollutants are discharged

62
Q

What is the NPRI?

A

National pollutant release inventory
Canada’s inventory of pollutant releases, disposals, and transfers
Has over 320 pollutants from over 7,000 facilities

63
Q

What is a non-point source?

A

Pollutants from diffuse sources

This is mainly due to precipitation

64
Q

How does the polarity affect pollutants?

A

Determines if they are water soluble

More negative = more water soluble

65
Q

What is the Kow?

A

Concentration in octanol/concentration in water

66
Q

What happens if there is a high Kow?

A

Hydrophobic (water-resistant)

Lipophilic (fat-soluble)

67
Q

What happens if there is a low Kow?

A

Hydrophilic (water-soluble)

Lipophobic (fat-resistant)

68
Q

When does the vapor pressure decrease?

A

With inc. weight

69
Q

What is fugacity?

A

The combination of the polarity, Kow, and vapor pressure to determine:

  • escaping tendency from compartment
  • establish equilibrium in chemicals between environmental phases
70
Q

What is the biota?

A

Air, soil, and water

71
Q

What is exposure?

A

Any condition which provides an opportunity for an external environment agent to contact human body
Magnitude x frequency x duration

72
Q

What is exposure assessment?

A

Measure or estimate the intensity, frequency, or duration of human exposure to an agent

73
Q

Dose-response assessment?

A

Characterize relationship between varying exposures and incidences of adverse effects in exposed populations

74
Q

What is PPM?

A

part per million

75
Q

What is PPB?

A

part per billion

76
Q

Bioconcentration is…

A

Net accumulation of a contaminant in an organisms from water ONLY

77
Q

What are the key components of bioaccumulation?

A

Uptake
Biotransform
Eliminate

78
Q

What is biotransformation?

A

Biologically mediated transformation of a chemical compound to another
Involves enzymes
Leads to inc. elimination

79
Q

How does biotransformation occur in metals?

A

Organic conversion by microbes
Sequestration by metallothioneins
Biomineralization

80
Q

How does biotransformation occur in organic chemicals?

A

Add polarity to more easily leave body (water soluble)

Conjugate polar chemicals

81
Q

What are the types of elimination of chemicals from the body?

A

Excretion: physical process
Biotransformation: chemical process
Depuration: contaminated organism placed in clean environment (loss of contaminant over time)

82
Q

How does the liver help with excretion?

A

Deals with organics mostly

Deals with large compounds

83
Q

How does the kidney help with excretion?

A

Deals with metals mostly

Deals with smaller compounds

84
Q

What is toxicology?

A

Study of adverse effects of chemicals on living organisms

85
Q

What is a dose response curve?

A

Describes how response to a toxicant changes with the dose

Supports causality between exposure and effect

86
Q

What are the assumptions of the dose response curve?

A

Response is due to the chemical
Magnitude of response due to the dose
Quantifiable method used to assess response

87
Q

What are biomarkers?

A
  • Biological response to a chemical that gives a measure of exposure & toxic effect
  • Alterations in cellular or biochemical components, or processes, structure, or functions that is measurable in a biological system or sample
88
Q

What biomarkers are used to study PAHs

A

DNA adducts (chemical covalently binds to DNA)
COMET assay
Phase 1 or 2 biomarkers
CYP1a/EROD

89
Q

Genotoxicity is…

A

When chemicals effect DNA

Cause DNA adducts

90
Q

What does a Comet assay do?

A

Measures DNA strand breaks in cells

91
Q

What are oxidative stress biomarkers?

A

Enzymes turned on when chemicals are polarized. There are reactive byproducts that attack DNA or oxidize lipids

92
Q

What does CYP1a do?

A

Chemical binds in cell that is taken to nucleus. Enzymes are turned on to attack chemical
CYP1a is a marker via EROD Assay to test if chemical is in nucleus.

93
Q

What do scientists care most about with pollution?

A

Growth
Reproduction
Survival

94
Q

What are endocrine disrupting chemicals (EDCs)?

A

Exogenous substance or mixture that alter functions of the endocrine system and consequently cause adverse health effects in an intact organisms, its progeny, or the population

95
Q

What can EDCs do to cells?

A

Mimic natural hormones by binding to their receptors

Alter recognition, biosynthesis, storage, release, transport, and clearance of hormones

96
Q

What do EDCs do to the body?

A 
Decline sperm quality
Impari fertility
Inc. spontaneous abortions
Decline sex ratios (less men)
Endometriosis
Early puberty
Neurobehavioral disorders
Pop. decline
97
Q

What is the endocrine system?

A

Collection of ductless tubes

Synthesize and secrete hormones

98
Q

How much EDCs are needed to cause effects?

A

About ppb

99
Q

Why would whole lakes be used as experiments?

A

Need ecosystems to show compelling evidence of changes in the environment due to pollution (such as acid rain, mercury, eutrophication…)
Biggest: 58 pristine lakes set aside in 1968 (was shut down for a time due to budget, but reopened by scientists as a non-profit)

100
Q

What is tiered testing?

A

Level 1: sorting & prioritization based upon existing info
Level 2: In vitro assays providing mechanistic data
Level 3: In vivo assay providing data about single endocrine mechanisms and effects
Level 4: in vivo assay providing data about multiple endocrine mechanisms and effects
Level 5: in vivo assays providing data on effects from endocrine and other mechanisms

101
Q

What is the adverse outcome pathway?

A

Showing step by step (concept model) the toxicant from making to outcomes

102
Q

What is the general adaptation syndrome (GAS)?

A

Non-specific changes constituting the body’s attempt to reestablish or maintain homeostasis while under the influence of a stressor. Hormones are released to get body to fight, but deplete after time.
Ex. getting sick when continually stressed

103
Q

What does the GAS have to do with pollutants?

A

The cortisol stress response can be impaired due to chemicals such as PAHs, PCBs, mercury, etc.
Can’t mount response b/c hormones deplete over time

104
Q

What is behavioral ecotoxicology?

A

Interaction of organisms with its external environment

105
Q

What are challenges of behavioral ecotoxicology?

A

Latency period
Inter species sensitivity
Are behavioral changes due to ecology or toxicology?
Not easy to monitor in nature
Is there any tolerance, resistance, or adaptation?

106
Q

What is commonly measured in behavioral ecotoxicology?

A

Avoidance (change in response to stimulus)
Activity level
Feeding
Performance

Pollution & Bioremediation (2 decks)

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