Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Environmental Toxicology > Midterm 2 (Lectures 6-10) > Flashcards

Midterm 2 (Lectures 6-10) Flashcards

1
Q

Name 4 things about organic compounds

A
  1. contain carbon
  2. carbon atoms form stable bonds with one another, thus numerous molecules (rings, chains, etc)
  3. low polarity
  4. low water soluble, fat soluble
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How to make organic compounds polar?

A

add polar functional groups (O, N, F)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

name 3 things about polar molecules

A
  1. have electrical charge
  2. more water soluble
  3. more chemically reactive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

name 3 things about polar molecules

A
  1. have electrical charge
  2. more water soluble
  3. more chemically reactive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Organic pollutants may be:

A
  • naturally occurring (hydrocarbons, nicotine)
  • non-naturally occurring (anthropogenic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the difference in evolution between naturally and non-naturally occurring compounds?

A

naturally: plants and animals and their toxins coevolve and have some detoxification mechanisms
non-naturally: detoxification mechanisms not evolved in organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Lipophilicity is:
hydrophilicity is:

A

a) associated with hydrocarbons
b) promoted when the substance carries a charge or when the organic compound has a high proportion of polar groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Name 3 types of organic pollutants

A
  • polycyclic aromatic hydrocarbons (PAHs)
  • polychlorinated biphenyls (PCBs)
  • pharmaceuticals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why are so many organic pollutants toxic?

A

they’re lipophilic = higher uptake potential, can pass right through lipid bilayer/diffuse through plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you measure polarity?

A

octanol-water partition coefficient (Kow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Kow =

A

concentration of solute in octanol / concentration of solute in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

partitioning between octanol and water in the lab is a model for:

A

the partitioning of a xenobiotic between the aqueous and lipid phase in vivo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Higher Kow =

A

more lipophilic. very useful in predicting the fate of a chemical in a biological system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

bioaccumulation:

A

processes in which a chemical substance is absorbed in an organism by all routes of exposure as occurs in the natural environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

bioaccumulation factor (BAF):

A

concentration in organism / concentration in water (or environment organism resides in)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

a) bioaccumulation formula:
b) bioconcentration formula:

A

a) net uptake (diet, respiratory, dermal absorption) - (elimination + growth dilution)
b) uptake from ambient environment only (no dietary uptake) - (elimination + growth dilution)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

bioconcentration:

A

the process in which a chemical substance is absorbed by an organism from the ambient environment only through its respiratory and dermal surfaces (chemical exposure in the diet is not included)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is bioaccumulation and bioconcentration measured?

A

bioaccumulation: in field scenarios
bioconcentration: in laboratory tests

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

bioaccumulation in net uptake and loss processes:

A

respiratory, dietary uptake, dermal and loss by egestion, passive diffusion, metabolism, transfer to offspring, growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the CEPA criteria for a) bioaccumulation factor, b) bioconcentration factor, and c) octanol-water partition?

A

a) ≥ 5000
b) ≥ 5000
c) log Kow ≥ 5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

a substance is considered bioaccumulative when the criterion is met for:

A

any one parameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Is BAF or BCF preferable?

A

BAF, use before relying on other parameters. better because it’s all route uptakes in field environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the CEPA criteria for environmental persistence in a) air, b) water, c) sediment, d) soil

A

a) ≥ 2 days
b) ≥ 6 months
c) ≥ 1 year
d) ≥ 6 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

a substance is considered persistent when the criterion is met for:

A

any one medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

describe the categorization of canada’s chemical management plan

A
  • was a prioritization process that involved the systematic identification of substances that should be subject to a screening assessment
  • new substances added to DSL have already undergone assessment and are therefore not subject to a screening assessment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

two phases of xenobiotic biotransformation reactions:

A

1) oxidation, reduction, hydrolysis
2) conjugation, synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Determining individual organism effects of xenobiotic requires info on:

A
  1. Fate and transformation in organism
  2. Interaction of xenobiotic with site of action
  3. Impact on whole organisms health
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

biotransformation:

A
  • the sum of the chemical reactions that occur within the body to alter the structure of a xenobiotic/endogenous compound
  • Occurs in many tissues and organs (intestine, lung)
  • Carried out by various enzyme systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

function of biotransformation:

A

conversion of xenobiotics into more hydrophilic, less toxic forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

toxicity can be affected in two possible ways:

A

1) Conversion into a less toxic form
2) Conversion into a more toxic form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Pesticide residues detected frequently in environment globally:

A
  • Several studies show presence in aquatic wildlife
  • Several studies show presence in human blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is a pesticide?

A
  • Any substance or mixture of substances used to destroy, suppress, or alter the life cycle of any pest
  • May be naturally or synthetically derived
  • Can also be an organism (bacillus thuringiensis, genetically modified crops)
  • Used in commercial, domestic, urban, and rural environments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Pesticides can be classified by:

A

1) Target organism (anticoagulants - rats)
2) Chemical structure (phenols)
3) Mode of action (sodium channel modulators)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

4 points on neonicotinoids:

A
  • Introduced in 1990s
  • Derived from nicotine
  • Among top 5 pesticides used globally
  • Applied onto seeds or soil prior to planting and/or spray onto foliage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is a neonicotinoid and what are its target?

A

1) Systemic insecticide: translocates throughout growing
2) Neurotoxic: nicotinic acetylcholine receptor agonist
3) Target pest: piercing-sucking insects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

imidacloprid general information and parameters:

A
  • Produced in Canada
  • Half life in water: ~30-162 days (degraded to guanidine compound by microbes)
  • Half life in soil: 1-2 years (high sorption tendency in dry soil)
  • Log KOW = 0.57
  • BAF/BCF not known
  • Highly water soluble (610mg/L at 20 C)
37
Q

what is neonicotinoids mode of action?

A

1) Bind to nAChR in postsynaptic neuron
2) Normally acetylcholine binds to these receptors and is degraded by acetylcholine esterase. Neonicotinoids are not degraded by this
3) Act as ‘false neurotransmitters’
4) Causes continuous activation of receptor, leading to symptoms of neurotoxicity
5) Has greater affinity for insect nAChR compared to vertebrate nAChR
- Formulations typically include other chemicals (silica, napthalene)

38
Q

how are neonics designed to target insects?

A
  • Binds more tightly and remains bound to nACh receptors in invertebrates
  • Continuous nervous system stimulation
  • Receptor binding irreversible so permanent effects are cumulative with time, and delayed toxicity exhibited
39
Q

acute toxicity testing does not detect:

A

‘delayed’ toxicity

40
Q

what are 4 interacting causes of bee decline?

A

1) reduction of cover crops such as alfalfa and clover, which are natural fertilizers and provide nutritious, combined with increased monoculture crop
2) monoculture with increased pesticide use
3) neonicotinoid use on plants not targeted for bees
4) bees own diseases and parasites

41
Q

neonicotinoid effects on bees:

A

adults: cause neurological disorders = depressed cognitive abilities such as learning, memory and habituation, olfaction and gustation, flight navigation and orientation
larvae exposed via brood food: reduced survival, pupation, altered metabolism, reduces olfactory responses as adults

42
Q

what is the rate of extinction of insects compared to invertebrates and why

A
  • Rate of insect extinction is 8 times faster than that of mammals, birds and reptiles
  • Intensive agriculture is the main driver of the declines, particularly heavy use of pesticides
  • Urbanism and climate change are also significant factors
  • 2.5% rate of annual loss over 25-30 years
43
Q

One of the biggest impacts of insect loss is:

A

on the many birds, reptiles, amphibians and fish that eat insects = cascading effects on insect eating species

44
Q

wetlands are:

A

Sensitive to pollution, biologically diverse, globally productive ecosystems

45
Q

Wetlands in agricultural areas under threat due to expansion and intensification:

A

Chemical fertilizer and pesticide pollution
Sedimentation, loss of vegetation

46
Q

Songbirds and neonics:

A

neonicotinoid insecticide reduces fueling and delays migration in songbirds. Migration is a critical period and timing matters. Reduced body mass and delayed migration may affect survival and breeding success. This may explain, in part, why farmland and migratory birds are in decline

47
Q

Pesticide use reporting in Canada:

A

confidential. Estimated via application rates and crop types

48
Q

Surface water:

A

wetlands situated within agricultural fields

49
Q

Lab species used in standard toxicity tests are:

A

not always most sensitive to neonicotinoids.
Wide range of differences in sensitivities between invertebrate taxa

50
Q

Species sensitivity distributions (SSDs):

A
  • more useful for deriving environmental quality
  • Models of the variation in sensitivity of species to a particular stressor
  • Are generated by fitting a statistical function to the proportion of species affected as a function of toxicant concentration or dose (based on specific endpoint)
51
Q

what is the goal of SSDs

A

predict concentration that will protect a given number of species in the environment. Often trying to protect ~95% of species. Must test at least 8 organisms to be useful

52
Q

Chronic toxicity vs. acute toxicity?

A
  • Mixture effects and delayed toxicity under chronic conditions poorly understood for most species
  • Single species lab tests relevant to field exposures in communities
53
Q

Toxicity modifying factor:

A

when toxicity of a substance is affected (increased or decreased) by some environmental (eg. pH), chemical, or biological (nutritional status of animal, sex, age) factor

54
Q

Net ecosystem production (NEP):

A

metabolism (gross primary production) - community respiration
- Estimated as the difference in dissolved oxygen concentration over a certain period of time

55
Q

Biochemical oxygen demand

A
  • The decay of organic matter in water
  • Remove a water sample from test vessel and measure the oxygen consumed by bacteria from the decomposition of organic matter in the water sample over a specific time period (5 days)
56
Q

Organic matter decomposition rate:

A

measure leaf litter mass in test vessels before and after exposure

57
Q

lines of evidence leading to impacts of neonicotinoids on ecosystems,
Highly toxic to insects:

A
  • Initial foliar/soil applications cause death in target pest but also non-target insects
  • Low-level chronic exposure of insects/aquatic inverts due to soil and water exposure = decreasing aquatic insect/invert population
58
Q

Neonicotinoid use in Canada

A

currently still registered for many uses but restricted compared to prior 2019 to protect pollinators, still state ‘phase out of all 3 neonics’ but does not appear to have a timeline

59
Q

Keystone species:

A

a species that has a disproportionately large effect on the communities in which it occurs. Helps to maintain local biodiversity within a community by:
- Controlling populations of other species that would otherwise dominate the community
- Providing critical resources for a wide range of species

60
Q

Ecotoxicity effects analysis:

A

endpoints ≥ population level

61
Q

Population dynamics:

A

Single species abundance
- Reductions if endangered
- Increases if invasive/pests
Reproductive success of individuals within the population
Alterations in genetics
Likelihood of extinction

62
Q

Community structure:

A
  • Reductions/increases in community structure (relative abundance of multiple species within a community)
  • Biodiversity changes (#species/community)
63
Q

Ecosystem:

A

Changes in ecosystem processes

64
Q

Landscape level effects:

A
  • Spatial distribution/extent of different habitat types within landscapes
  • Changes in size, shape, proximity of different habitats
65
Q

Metal mines in Canada are commonly classified by primary commodity type:

A
  • Base metals: copper, zinc, lead, nickel
  • Precious metals: gold, platinum group metals, silver
  • Uranium
  • Iron ore
  • Other metals: titanium, tantalum, tungsten, nobium, magnesium
66
Q

Mine tailings:

A
  • Size and composition depends on mining method
  • For hard rock metal mines usually a very fine mud or powder, which is left over after ore is crushed and valuable minerals are extracted
  • May also contain chemicals used for mine extraction
67
Q

Env. Canada requires an environmental impact assessment during:

A
  • Planning and construction (clearing/blasting)
  • Operations (wastewater/tailings management)
  • Closure (clean-up/maintenance/monitoring)
68
Q

environmental impact assessment formula

A

EIA = ER + physical stressors (habitat)

69
Q

Metal Mining Effluent Regulations (MMER)
Include provisions to allow the discharge of metal mine effluent into fish-frequented water bodies, subject to certain requirements regarding:

A
  • Discharge limits
  • Acute lethality
  • Environmental effects on fish, fish habitat, and fisheries resources
70
Q

Overall goal of MMER:

A

to minimize the effect of mine effluent on waters frequented by fish

71
Q

Mines that are subject to MMER may deposit an effluent that contains are deleterious subject if:

A
  • The concentration of the deleterious substance in the effluent does not exceed the authorized limits
  • The pH of the effluent is 6.0-9.5
  • The effluent is not acutely lethal (grab sample monthly + monthly testing)
    (Effluent is deemed not acutely lethal if it kills less than 50% of the rainbow trout subjected to it at 100% concentration over a 96 hour period)
72
Q

EEM:

A

provides framework and methods for collection of data on:
Fish health (5 endpoints)
Benthic invertebrate community structure (4 endpoints)
Water quality and effluent monitoring

73
Q

Howe Sound: Contaminants discharged in industrial effluents:

A

Organochlorines
Metals
Sulphuric acid
Mercury

74
Q

Acid mine draining:

A

Natural mineralization at Britannia contains metal sulphides which when exposed to air and water react to form a sulphuric acid solution containing dissolved metals. This mixture = acid mine drainage and can be very toxic to aquatic life

75
Q

Prior to mining, the metal sulphide ore existed with:

A

little environmental impact. Local discolouration of smaller creeks may have occurred as a result of oxidation however very little, if any, adverse effects would have occurred at Britannia Creek or Howe Sound
Portals created from mining now cause these sulphides to run off into larger water bodies (creeks, howe sound)

76
Q

Pollution prevention measures at Britannia involve:

A
  • Collecting all acid mine drainage
  • Treating acid mine drainage
  • Controlling discharge of contaminated ground water (closing portals)
  • Reducing or preventing the formation of acid mine drainage by covering sulphide mineralization with soils and re-routing uncontaminated surface waters away from underground mine workings
77
Q

Diversity, species diversity, and biodiversity describe:

A

aspects of richness and relative abundance in a community

78
Q

The broadcast term ‘biodiversity’ applies to:

A
  • Richness of alleles of a particular genetic locus
    #’s of plant, animal and microbial species/region
  • Variety of communities on a landscape or geographic region
79
Q

Mathematical models to calculate biodiversity:

A

Shannon-Weiner index
Simpson’s index

80
Q

Intertidal zone:

A

resident species and useful for establishing if pollution present and nursery for many subtidal species

81
Q

Biodiversity Indices:

A

provide a way to quantify the relationship between species number and relative abundance, useful for comparisons across sites

82
Q

Relative abundance =

A

species / total number of species

83
Q

Species richness =

A

how many different species were at the site

84
Q

Rank-abundance diagram:

A
  • Calculate relative abundance of each species
  • Rearrange data from most to least abundant
  • Plot relative abundance of each species vs. rank
    ->Slower slope = higher evenness (abundance)
    -> Longer length of curve = higher species richness
85
Q

Reference toxicant:

A

toxicant previously tested with known concentration/dose response curves for the endpoint of interest

86
Q

purpose of reference toxicant:

A
  • determine sensitivity of test organisms over time
  • Assess comparability within and between lab test results and identify potential sources of variability (ie. test organism health, differences among batches of organisms, etc)
87
Q

Shannon-Weiner Index

A

H’ = -Σ(pi)(ln pi)

88
Q

Σ = a)
pi = b)
Proportion = c)
The higher the H’ = d)
Rare species contribute: e)
H’ max = f)
Exp (H’) = g)
J’ = h)

A

a) sum of all species
b) proportion of individual species (i)
c) %, relative abundance = 19.57, proportion = 19.57/100 = 0.1957
d) the higher the diversity
e) very little to H’
f) ln (S), S = # of species), maximum possible diversity
g) eH’ = equivalent # of equally common species
h) H’/H’ max = evenness (how evenly individuals are distributed among species)

Environmental Toxicology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions