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

Chapter 4: Impact assessments Flashcards

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
Q

How has the International Agency for Research on Cancer (IARC) addressed the difficulty in determining the carcinogenicity of specific chemicals?

A

Four toxicity categories have been proposed
by the International Agency for Research on Cancer (IARC)

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26
Q

What does TLV stand for, who sets it, and what is its purpose?

A

TLV (threshold limit value) is set by the American Conference of
Governmental Industrial Hygienists (ACGIH) to address the
airborne exposure concentration limit at workplace.

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27
Q

How are TLV values determined?

A

TLV values are determined based on a concentration level for which no adverse effects would be expected over a worker’s lifetime.

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28
Q

Who sets the PEL (Permissible Exposure Limit) for workplace conditions ?

A

The PEL (Permissible Exposure Limit) for workplace conditions is set by the US Occupational Safety and Health Administration (OSHA).

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29
Q

What organization sets the REL (Recommended Exposure Limits) and what was it based on?

A

The REL (Recommended Exposure Limits) are set by the National Institute for Occupational Safety and Health (NIOSH) based on its research on chemical toxicities.

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30
Q

What is the impact of PEL values?

A

PEL values have legal implications in defining workplace
conditions.

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31
Q

What is the difference between TLV, REL, and PEL values?

A

TLV and REL represent scientific and
professional assessments of chemical hazards, and are preferred
for use in human risk impact assessment.

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32
Q

What is non-carcinogenic toxicity index controlled by?

A

A threshold exposure, such that doses below a threshold value
do not manifest a toxic response.

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33
Q

What is the threshold in Non-carcinogenic toxicity index based on?

A

A dose-response
relationship curve generated by tests on mammals, rats and
guinea pigs.

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34
Q

What is the purpose of defining a reference dose of the no
observed adverse effect level (NOAEL) ?

A

To account for the uncertainties in extrapolating from the test
species to humans and the variation in sensitivity within the human
population

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35
Q

What is the non-carcinogenic impact?

A

The ratio of actual dose over the reference dose RfD.

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36
Q

What level of non-carcinogenic impact is considered to cause health concern?

A

A non-carcinogenic impact of larger than 1 is considered to cause
health concern.

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37
Q

What are the three pathways for human exposure to chemicals?

A

– inhalation by breathing

– ingestion by drinking contaminated water

– direct contact through the skin

38
Q

What is environmental fate?

A

The dispersion of pollutants/toxins through air, water, and soil once released into the atmosphere.

39
Q

How can the pollutant concentration surrounding the source of released chemicals be estimated?

A

Using steady-state Gaussian plume dispersion models.

40
Q

How can health toxicity of a compound be characterized by?

A

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
Q

How can the impact potential of toxic chemicals on ecosystems be characterized?

A

By the environmental lifetime of the
chemical, bioaccumulation factor and lethal
dose/concentration (LD50 or LC50) to animal species.

42
Q

How can the environmental impacts of toxic compounds on global
warming, stratospheric ozone depletion, acid rain
formation and smog formation be assessed?

A

Based on
the process emissions and the impact potential indices.

43
Q

Why is a comprehensive public health impact assessment needed?

A

To combine the characterization factor (including
exposure potential and toxicity potential) and the
emission rate.

44
Q

What type of impact can be assessed similarly to the comprehensive public health impact assessment?

A

The ecosystem impact can be assessed
in a similar way.

45
Q

Write down the general form of a dimensionless environmental impact index.

A

Check the chapter 4 slides

46
Q

What does Wien’s Law describe?

A

The relationship between the wavelength at which radiation
is emitted from a black body and the temperature of the
emitter.

47
Q

Write the energy balance that relates infrared radiation (IR) to ultraviolet light and visibile light.

A

Check the annotated slides.

48
Q

What is the relationship between Qout (energy from infrared radiation) and the temperature of the earth?

A

If Qout decreases then temperature of Earth increases.

49
Q

What type of potential is the chemical’s tropospheric residence time?

A

Exposure Potential

50
Q

What type of potential is the strength of its infrared radiation absorbance/

A

Impact potential

51
Q

How does the depletion of ozone in the atmosphere affect the balance of energy on Earth and the role of greenhouse gases (GHGs)?

A

Depletion of ozone means less energy deflected by Earth and more energy held within atmosphere by GHG

52
Q

How can rain be acidified?

A

Chemical compounds dissolving in rain in atmosphere, releases H+, acidifying the rain.

53
Q

What does the intensity of the photon depend on?

A

Latitude, time of the year, and time of the day.

54
Q

What is the reason that ozone shouldn’t be on the ground level?

A

Because it is a strong oxidizing agent, can cause medical aspiration, and damage to fetuses.

55
Q

What is the relationship between residence time and exposure potential?

A

Longer residence time = higher exposure potential

56
Q

What is the relationship between the strength of infrared absorbance and impact potential?

A

Increase in strength of infrared absorbance = increase in impact potential

57
Q

What is the impact of the destruction of the ozone layer on global warming?

A

Destruction of the ozone layer contributes to global warming

58
Q

How can ozone concentration increase?

A

By increasing the amount of nitrogen dioxide which leads to more ozone.

59
Q

What is DDT?

A

A pesticide that kills insects.

60
Q

What species are LC50 or LD50 values based on?

A

Algae (green) , daphnid (daphnid magna), and fish (rainbow trout or blue gill)

61
Q

What is the BCF?

A

Ratio of chemical’s concentration
in the tissue of an aquatic organism to its
concentration in water.

62
Q

What is the difference between carcinogenic and non-carcinogenic impact in terms of time assumptions?

A

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
Q

How can you obtain the CPF (carcinogenic potency factor) or CSF (cancer potency slope factor)?

A

You can obtain these numbers through animal testing.

64
Q

What is the intake fraction?

A

How much pollution is absorbed by humans.

65
Q

What does the intake fraction account for?

A

The dispersion in multimedia environment (Fate) and the exposure

66
Q

What does the characterization factor account for?

A

Dispersion, exposure, and toxicity, which is equivalent to the human impact potential index.

67
Q

Why is the characterization factor not constant?

A

Because exposure (iF) varies with the population.

68
Q

What was the first generation of refrigerants?

A

Chlorofluorocarbons (CFCs)

69
Q

What is the new generation of refrigerants?

A

Hydrochlorofluorocarbons (HCFCs)

70
Q

What is the difference between most CFCs and HCFCs in terms of stratospheric ozone depletion?

A

Most CFCs have a higher ozone depletion compared to HCFCs

71
Q

What happens when chemical compounds dissolve in the rain?

A

They release H+ ions, thus acidifying the rain.

72
Q

What is the relationship between incremental reactivity and ozone formed?

A

The more reactive the compound, the more ozone is formed.

73
Q

What is the relationship between nitrogen oxide and incremental reactivity?

A

Incremental reactivity increases with increasing nitrogen oxide levels

74
Q

What does ROG refer to when it comes to smog formation potential and maximum incremental reactivity?

A

Base reactive organic gas mixture

75
Q

What is the water-octanol partition coefficient widely used for?

A

To estimate the
toxicological and environmental fate parameters.

76
Q

What is the carcinogenic potency factor (CPF)/cancer potency slope factor (CSF)?

A

the change in
incremental “lifetime” probability of contracting cancer
due to a daily chemical dosage of the carcinogen of 1
mg/kg/day

77
Q

Compare the availability of Carcinogenic Toxicity and Impact values compared to PEL and TLV values

A

Carcinogenic toxicity and impact values are not as widely available as PEL and TLV values.

78
Q

What is the dermal absorbed dose a function of?

A
  • 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
Q

Where is the intake fraction higher based on population density?

A

Higher in more population dense areas

80
Q

What is a similar impact that can be assessed similarly to the comprehensive public health impact assessment?

A

The ecosystem impact.

81
Q

Write the reaction that forms monatomic oxygen in the stratosphere

A

O2 + hν(~0.2 µm) = 2O* (monatomic
oxygen)

82
Q

Write the reaction that forms ozone in the stratosphere.

A

O* + O2 + M = O3 + M (M is an energy
accepting body)

83
Q

Write the reaction that forms diatomic and monatomic oxygen

A

O3 + hν (~0.32 µm) = O2 +O*

84
Q

What are chloroflourocarbon (CFC) compounds and what are their properties.

A

Chlorofluoro compounds
(CFCs) are synthetic chemicals.
Chemically inert and used as
solvent and coolants. Their
residence times are more than 100
years

85
Q

How do CFCs move up into the stratosphere due to long residence times?

A

Diffusion or dispersion.

86
Q

What must NO be converted to before ozone builds up in the lower atmosphere?

A

Nitrogen dioxide

87
Q

What happens if the carcinogenic impact exceeds 10^(-4)?

A

Unsafe; leads to increased cancer risk.

88
Q

What do TLV values depend on and what are they set as?

A

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
Q

What influences PELs?

A

PELs are also directly influenced by
political, economic and feasibility issues.

90
Q

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

A reference dose (RfD) is defined as 1/(10x10) of the no
observed adverse effect level (NOAEL), expressed as mg/kg/day

91
Q

How do you estimate the overall impact for a particular category “k” of all chemical compounds from a process?

A

Sum the contributions for each chemical
weighed by their emission rate

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

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