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CHBE 370 (Fundamentals of Sustainable Engineering) > Chapter 4: Impact assessments > Flashcards

Chapter 4: Impact assessments Flashcards

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1
Q

What follows the development of materials, energy, and emissions inventories in environmental assessments?

A

After the materials, energy, and emissions inventories are developed, the impacts of those wastes and pollutants on the environment, human health, and economics can be evaluated.

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2
Q

What are examples of impact categories for environmental assessments?

A

Global impacts:

-Global warming (greenhouse gas emissions).

-Stratospheric ozone depletion.

Regional/local impacts:
-Acid rain formation.

-Smog formation.

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3
Q

What is the global warming potential mostly influenced by?

A

The chemical’s tropospheric
residence time and the strength of its infrared
radiation absorbance.

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4
Q

Where is monatomic oxygen located?

A

Upper atmosphere (chemosphere) above stratosphere.

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5
Q

Where is oxygen gas and ozone formed?

A

In the lower stratosphere.

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6
Q

What is the role of the ozone layer in the stratosphere?

A

To absorb ultraviolet (UV) radiation that penetrates through the upper atmosphere.

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7
Q

Why does the ozone layer form in the stratosphere?

A

As a result of reaction equilibrium and to absorb UV radiation.

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8
Q

What is the criteria for a compound to cause stratospheric ozone
depletion?

A

It must have a lifetime in the
atmosphere sufficient to reach the stratosphere and
reacts with atomic oxygen

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9
Q

What is the potential for acidification for any compound related to?

A

The number of moles of H+ created per number of moles
of the compound emitted

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10
Q

What is nitrogen dioxide?

A

A light absorbing gas,
which converts the light energy (photons)
into its internal energy and forms excited monatomic oxygen, and ozone and smog in the
troposphere due to photochemical reactions

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11
Q

What is incremental reactivity?

A

The amount of O3
formed per unit amount of VOC added to a VOC
mixture that is representative of conditions of urban
and rural areas.

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12
Q

What componets are apart of an ecosystem?

A

Plants, animals, their physical
environment, and the dynamic processes that link them.

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13
Q

What are the factors that determine the impact of releases of toxic chemicals into the ecosystem on living animals?

A
  1. The toxicity of the chemicals to the animals.
  2. The exposure potential of the animals to these chemicals.
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14
Q

What does the persistence of toxic chemical release in the environment depend on?

A

Partitioning in
dispersion media (e.g. air, water and soil) and their
degradation (both biological and oxidative).

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15
Q

How can the risk of animals/mammals exposure to toxic chemicals be characterized?

A

By the LC50 or LD50, the
lethal concentration or lethal dose to 50% of the
population over a certain exposure period

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16
Q

Where can LC50 and LD50 data be found?

A

Health database
or, for daphnids, fish and guppies, can be calculated
based on its water-octanol partition coefficient Kow.

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17
Q

What is the water-octanol partition coefficient

A

The ratio of the chemical’s concentration in
octanol to the chemical’s concentration in water,
representing its partitioning between organic and
aqueous phases.

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18
Q

What does it mean when a compound has a high value of BCF?

A

It indicates
that a living organism will tend to extract a
material from an aqueous phase.

High BCF means the chemical easily dissolves in the oil phase and is very toxic to the point where you have to be hospitalized

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19
Q

How are toxic chemicals emitted to the environment degraded?

A

Through various reactions, including photo-oxidation and biodegradation.

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20
Q

How can the lifetime of toxic compounds in the environment be estimated?

A

By considering their reactions in different environmental media. This estimation helps assess how long these chemicals persist in the environment.

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21
Q

What is risk in human health risk assessment?

A

Risk is the probability of suffering harm or loss.

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22
Q

How is the degree of risk determined?

A

By the
probability of the exposure and the severity of
consequence, i.e. Risk = f (Exposure, Hazard)

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23
Q

What would a quantitative risk assessment associated with pollution include?

A

– Hazard identification

– Exposure potential assessment

– Toxicity assessment

– Risk characterization.

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24
Q

How are toxic chemicals categorized?

A

Carcinogenic and non-carcinogenic

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25
How has the International Agency for Research on Cancer (IARC) addressed the difficulty in determining the carcinogenicity of specific chemicals?
Four toxicity categories have been proposed by the International Agency for Research on Cancer (IARC)
26
What does TLV stand for, who sets it, and what is its purpose?
TLV (threshold limit value) is set by the American Conference of Governmental Industrial Hygienists (ACGIH) to address the airborne exposure concentration limit at workplace.
27
How are TLV values determined?
TLV values are determined based on a concentration level for which no adverse effects would be expected over a worker's lifetime.
28
Who sets the PEL (Permissible Exposure Limit) for workplace conditions ?
The PEL (Permissible Exposure Limit) for workplace conditions is set by the US Occupational Safety and Health Administration (OSHA).
29
What organization sets the REL (Recommended Exposure Limits) and what was it based on?
The REL (Recommended Exposure Limits) are set by the National Institute for Occupational Safety and Health (NIOSH) based on its research on chemical toxicities.
30
What is the impact of PEL values?
PEL values have legal implications in defining workplace conditions.
31
What is the difference between TLV, REL, and PEL values?
TLV and REL represent scientific and professional assessments of chemical hazards, and are preferred for use in human risk impact assessment.
32
What is non-carcinogenic toxicity index controlled by?
A threshold exposure, such that doses below a threshold value do not manifest a toxic response.
33
What is the threshold in Non-carcinogenic toxicity index based on?
A dose-response relationship curve generated by tests on mammals, rats and guinea pigs.
34
What is the purpose of defining a reference dose of the no observed adverse effect level (NOAEL) ?
To account for the uncertainties in extrapolating from the test species to humans and the variation in sensitivity within the human population
35
What is the non-carcinogenic impact?
The ratio of actual dose over the reference dose RfD.
36
What level of non-carcinogenic impact is considered to cause health concern?
A non-carcinogenic impact of larger than 1 is considered to cause health concern.
37
What are the three pathways for human exposure to chemicals?
– inhalation by breathing – ingestion by drinking contaminated water – direct contact through the skin
38
What is environmental fate?
The dispersion of pollutants/toxins through air, water, and soil once released into the atmosphere.
39
How can the pollutant concentration surrounding the source of released chemicals be estimated?
Using steady-state Gaussian plume dispersion models.
40
How can health toxicity of a compound be characterized by?
The threshold limit values (TLV) and/or permissible exposure limits (PELs) of chemicals, or the clinically defined reference dose (RfD) for toxic non-carcinogenic chemicals, and the cancer slope/potency factor (CSF, CPF) for carcinogenic chemicals.
41
How can the impact potential of toxic chemicals on ecosystems be characterized?
By the environmental lifetime of the chemical, bioaccumulation factor and lethal dose/concentration (LD50 or LC50) to animal species.
42
How can the environmental impacts of toxic compounds on global warming, stratospheric ozone depletion, acid rain formation and smog formation be assessed?
Based on the process emissions and the impact potential indices.
43
Why is a comprehensive public health impact assessment needed?
To combine the characterization factor (including exposure potential and toxicity potential) and the emission rate.
44
What type of impact can be assessed similarly to the comprehensive public health impact assessment?
The ecosystem impact can be assessed in a similar way.
45
Write down the general form of a dimensionless environmental impact index.
Check the chapter 4 slides
46
What does Wien's Law describe?
The relationship between the wavelength at which radiation is emitted from a black body and the temperature of the emitter.
47
Write the energy balance that relates infrared radiation (IR) to ultraviolet light and visibile light.
Check the annotated slides.
48
What is the relationship between Qout (energy from infrared radiation) and the temperature of the earth?
If Qout decreases then temperature of Earth increases.
49
What type of potential is the chemical's tropospheric residence time?
Exposure Potential
50
What type of potential is the strength of its infrared radiation absorbance/
Impact potential
51
How does the depletion of ozone in the atmosphere affect the balance of energy on Earth and the role of greenhouse gases (GHGs)?
Depletion of ozone means less energy deflected by Earth and more energy held within atmosphere by GHG
52
How can rain be acidified?
Chemical compounds dissolving in rain in atmosphere, releases H+, acidifying the rain.
53
What does the intensity of the photon depend on?
Latitude, time of the year, and time of the day.
54
What is the reason that ozone shouldn't be on the ground level?
Because it is a strong oxidizing agent, can cause medical aspiration, and damage to fetuses.
55
What is the relationship between residence time and exposure potential?
Longer residence time = higher exposure potential
56
What is the relationship between the strength of infrared absorbance and impact potential?
Increase in strength of infrared absorbance = increase in impact potential
57
What is the impact of the destruction of the ozone layer on global warming?
Destruction of the ozone layer contributes to global warming
58
How can ozone concentration increase?
By increasing the amount of nitrogen dioxide which leads to more ozone.
59
What is DDT?
A pesticide that kills insects.
60
What species are LC50 or LD50 values based on?
Algae (green) , daphnid (daphnid magna), and fish (rainbow trout or blue gill)
61
What is the BCF?
Ratio of chemical’s concentration in the tissue of an aquatic organism to its concentration in water.
62
What is the difference between carcinogenic and non-carcinogenic impact in terms of time assumptions?
Carcinogenic impacts are focused on long-term impacts on health Non-carcinogenic impact is focused on the shorter-term health impact of the compound.
63
How can you obtain the CPF (carcinogenic potency factor) or CSF (cancer potency slope factor)?
You can obtain these numbers through animal testing.
64
What is the intake fraction?
How much pollution is absorbed by humans.
65
What does the intake fraction account for?
The dispersion in multimedia environment (Fate) and the exposure
66
What does the characterization factor account for?
Dispersion, exposure, and toxicity, which is equivalent to the human impact potential index.
67
Why is the characterization factor not constant?
Because exposure (iF) varies with the population.
68
What was the first generation of refrigerants?
Chlorofluorocarbons (CFCs)
69
What is the new generation of refrigerants?
Hydrochlorofluorocarbons (HCFCs)
70
What is the difference between most CFCs and HCFCs in terms of stratospheric ozone depletion?
Most CFCs have a higher ozone depletion compared to HCFCs
71
What happens when chemical compounds dissolve in the rain?
They release H+ ions, thus acidifying the rain.
72
What is the relationship between incremental reactivity and ozone formed?
The more reactive the compound, the more ozone is formed.
73
What is the relationship between nitrogen oxide and incremental reactivity?
Incremental reactivity increases with increasing nitrogen oxide levels
74
What does ROG refer to when it comes to smog formation potential and maximum incremental reactivity?
Base reactive organic gas mixture
75
What is the water-octanol partition coefficient widely used for?
To estimate the toxicological and environmental fate parameters.
76
What is the carcinogenic potency factor (CPF)/cancer potency slope factor (CSF)?
the change in incremental “lifetime” probability of contracting cancer due to a daily chemical dosage of the carcinogen of 1 mg/kg/day
77
Compare the availability of Carcinogenic Toxicity and Impact values compared to PEL and TLV values
Carcinogenic toxicity and impact values are not as widely available as PEL and TLV values.
78
What is the dermal absorbed dose a function of?
* The contact skin area * Quantity deposited on the skin per unit area per event * The weight fraction of chemical of concern in the mixture (W) * The fraction of the “applied dose absorbed (ABS)” and the number of exposure events per day
79
Where is the intake fraction higher based on population density?
Higher in more population dense areas
80
What is a similar impact that can be assessed similarly to the comprehensive public health impact assessment?
The ecosystem impact.
81
Write the reaction that forms monatomic oxygen in the stratosphere
O2 + hν(~0.2 µm) = 2O* (monatomic oxygen)
82
Write the reaction that forms ozone in the stratosphere.
O* + O2 + M = O3 + M (M is an energy accepting body)
83
Write the reaction that forms diatomic and monatomic oxygen
O3 + hν (~0.32 µm) = O2 +O*
84
What are chloroflourocarbon (CFC) compounds and what are their properties.
Chlorofluoro compounds (CFCs) are synthetic chemicals. Chemically inert and used as solvent and coolants. Their residence times are more than 100 years
85
How do CFCs move up into the stratosphere due to long residence times?
Diffusion or dispersion.
86
What must NO be converted to before ozone builds up in the lower atmosphere?
Nitrogen dioxide
87
What happens if the carcinogenic impact exceeds 10^(-4)?
Unsafe; leads to increased cancer risk.
88
What do TLV values depend on and what are they set as?
The length of exposure time and are set as time-weighted average (TWA) values over a specified period, such as 1-hour or 8-hours.
89
What influences PELs?
PELs are also directly influenced by political, economic and feasibility issues.
90
How is a reference dose defined to account for the uncertainties in extrapolating from the test species to humans and the variation in sensitivity within the human population?
A reference dose (RfD) is defined as 1/(10x10) of the no observed adverse effect level (NOAEL), expressed as mg/kg/day
91
How do you estimate the overall impact for a particular category "k" of all chemical compounds from a process?
Sum the contributions for each chemical weighed by their emission rate

CHBE 370 (Fundamentals of Sustainable Engineering) (11 decks)

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