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Environmental Toxicology > Midterm 3 (Lectures 11, 12, 13) > Flashcards

Midterm 3 (Lectures 11, 12, 13) Flashcards

1
Q

Canadian tar sands mining are the ____ largest oil reserves in the world

A

fourth

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2
Q

Open pit mining occupies ____ square kilometres

A

1030

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3
Q

Northern Alberta’s oilsands are located directly upstream of:

A

wood buffalo national park

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4
Q

what is oil sands process water?

A

any water that has been in contact with the tar sand. produced during the extraction phase where bitumen is separated from sand and silt

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5
Q

estimate of ____ barrels OSPW produced in 2014, estimated _____ barrels OSPW expected by 2030

A

2.15 million/day
3.93 million/day

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6
Q

Where does OSPW go?

A

large tailings ponds due to no discharge policy

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7
Q

OSPW can be toxic to:

A

prokaryotes and eukaryotes

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8
Q

small amounts of remediation of OSPW occurs during:

A

oxidation and photodegradation

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9
Q

is there a way for OSPW to be released back into the environment?

A

No, no efficient or cost effective way

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10
Q

what is the composition of ospw?

A

70-80% water
20-30% solids (sand, silt, clay minerals)
1-3% residual bitumen

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11
Q

what changes the composition of ospw?

A

age, source, location within tailings ponds

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12
Q

ospw has around 3000 ______

A

elemental compositions

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13
Q

what are the most common elemental compositions of ospw?

A

naphthenic acids (NA)
polycyclic aromatic compounds (PAC)
BTEX (benzene, toluene, ethyl benzene, xylene)
phenols
heavy metals
ions (sodium, sulfate, bicarbonate, chloride)

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14
Q

what are two facts of wood frogs?

A
  1. adults lay eggs in marsh lands or small ponds
  2. after hatching, tadpoles spend 3-4 months entirely aqueous until metamorphosis
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15
Q

why use wood frogs as a receptor species?

A

native species to the tar sands region

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16
Q

what were some of the effects of NAs on wood frogs?

A

mortality, birth defects, decreased growth and development

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17
Q

What are NAs and where are they found?

A

NAs are natural in origin, are detected near bitumen deposits

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18
Q

what are NA levels upstream and downstream of the tar sands?

A

up: 1-5 μg/L
down: up to 10 μg/L = LC50 of wood frog exposure

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19
Q

how many operational tar sands mines are in one area?

A

8

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20
Q

what are two difficulties of having tar sand mines so close together?

A
  1. how do you identify that the results are due to tar sands and not natural erosion?
  2. how do you identify which mine is responsible?
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21
Q

how many metal and diamonds mines were subject to MMER in 2003 vs 2018?

A

2003: 73
2018: 140 metal, 5 diamond

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22
Q

what are the 2 requirements of environmental effects monitoring (EEM)? what do they measure?

A
  1. water quality monitoring: effluent characterization and sublethal testing on fish
  2. biological monitoring: statistical assessment of ‘effects’ (exposed vs. unexposed)
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23
Q

what are the 2 requirements for water quality monitoring studies and what do they measure?

A
  1. water quality monitoring: changes in receiving environment due to mine discharge, compares water quality from exposed and reference areas (deleterious substances & other parameters: metals, ammonia, nitrate, pH, DO, temp, TOC, DOC, sulphate, alkalinity)
  2. sublethal toxicity testing on effluent: is there evidence that mine effluent affects fish, inverts, aquatic plants? does it change over time?, fish early life stage development, reproduction of an invertebrate, algal growth inhibition and reproduction
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24
Q

how often is sublethal toxicity testing on effluent required?

A

2x/year for first 3 years

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25
Q

name one fish species, invert species, plant species, algal species, and marine species used for effluent testing, as well as what is tested:

A

fish: fathead minnow - larval growth and survival
invert: ceriodaphnia dubia - reproduction and survival
plant: lemna minor - inhibition of growth
algal: pseudokirchneriella subcapitata - inhibition of growth
marine: giant kelp (macrocystis pyrifera) - inhibition of growth

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26
Q

biological monitoring studies in receiving environment to determine if effluent has an effect on:

A

a) fish (fish population survey)
b) fish habitat (benthic invertebrate community survey)
c) fish tissue survey (only conducted in Hg concentration greater or equal to 0.10 μg/L in effluent)

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27
Q

when are biological monitoring studies required?

A

every 3 years but if no effects every 6 years

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28
Q

name 2 core indicators for fish surveys (what they measure and what the indicator is):

A

1) liver weight relative to body weight - energy storage (liver somatic index)
2) body weight relative to body length - condition

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29
Q

name 2 core indicators for benthic invertebrate community surveys (what they measure and what the indicator is):

A

1) total abundance - number of animals
2) taxon richness - number of taxa or kinds of animals

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30
Q

what do Simpson’s index and Bray-Curtis index measure?

A
  • how evenly the animals are distributed among the taxa
  • overall community composition
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31
Q

when is relative gonad size, relative liver size, and condition considered statistically significant in fish surveys?

A
  • +/- 25%
  • +/- 25%
  • +/- 10%
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32
Q

when is the parameters for benthic communities surveying considered statistically significant?

A

+/- 2 SD

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33
Q

what is CES?

A

a threshold difference between reference and exposed site above which effects may be indicative of potential higher risk to the environment

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34
Q

what has CES been developed for?

A

fish population and benthic inver community components of the metal and diamond mining effluent regulations

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35
Q

what parameters did sublethal toxicity from the polley mine leak most effect? least effect?

A

invertebrate reproduction, aquatic plant growth (up/down), least = fish larval growth

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36
Q

tailings are:

A

crushed rock left over after copper/gold is removed

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37
Q

tailings contain ____ levels of copper compared to:

A

higher, natural background levels in surrounding rocks that are not mined

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38
Q

how big is the mount polley mine?

A

20,000 Ha, processes 20,000 tons/day

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39
Q

what are the 6 ways amphibian and fish species can be exposed to effluent?

A
  • water ingestion
  • direct contact (pore water/surface water)
  • food consumption
  • direct contact (sediment)
  • incidental sediment ingestion
  • contact with resuspended sediment
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40
Q

what is the biotic ligand model?

A

gill surface referred to as biotic ligand and gill cells possess several ion channels that typically regulate essential nutrients (calcium, sodium), also where free metal cations can bind and enter the gill cells preventing uptake of essential nutrients

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41
Q

what does BLM cause?

A

osmotic imbalances and/or deficiencies in essential nutrients in organism = harms/destroys gill epithelium

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42
Q

what does the BLM describe?

A

interactions between metals, metal species, metal complexes and constituents in water such as hardness, pH

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43
Q

what were the physical, biological and chemical effects of mount polley impact?

A

physical: increased turbidity, immediate loss of terrestrial and aquatic communities
biological: loss of soil and sediment communities in affected areas; limited evidence of metal toxicity, plants growing through tailings in some areas
chemical: relatively inert, higher concentrations of Cu in soil, sediment, water, release of metals unlikely, vanadium levels increased

44
Q

what was the effect of the mount polley leak on rainbow trout?

A

ovary Selenium significantly increased, loss of spawning for 2 years in Hazeltine Creek due to habitat destruction

45
Q

what changes in concentrations did mount polley see post breach:

A

water copper, aluminium, arsenic concentrations increased post breach

46
Q

why was it difficult to measure post breach effects for mount polley?

A

there wasn’t very many pre-breach measurements and testing completed

47
Q

why did the mount polley tailings pond fail?

A

poorly constructed, built on a sloped glacial lake, weakening its foundation, didn’t count for drainage or erosion failures associated with glacial til beneath pond

48
Q

what are the 3 basic components of the endocrine system? what do they do?

A
  1. endocrine gland/cell
    - secrete hormones
    - effects distal target
  2. hormone
    - chemical products
    - released upon stimulation
  3. target organ
    - express hormone-specific receptors
    - show biological response
49
Q

hormones control:

A

major physiological processes

50
Q

what are these hormones targets and what are their responses:
1. ACTH
2. Follicle-stimulating hormone (FSH), luteinizing hormone (LH)
3. growth hormone (GH)
4. prolactin (PRL)
5. thyroid-stimulating hormone (TSH)

A
  1. adrenal cortex -> production of glucocorticoids
  2. testes or ovaries -> production of sex hormones; control of menstrual cycle
  3. many tissues -> growth
  4. mammary glands -> mammary gland growth; milk production
  5. thyroid -> production of thyroid hormones
51
Q

what are the two ways hormones are activated?

A
  • cell membrane receptors
  • intracellular receptors
52
Q

what is an endocrine disrupting substance?

A

an exogenous substance/mixture that alters the function of the endocrine system, resulting in adverse health effects

53
Q

what makes endocrine disrupting substances different than other toxicants?

A
  • effects at low concentrations
  • critical windows of exposure extremely susceptible
54
Q

what are two of the critical windows to be exposed to an endocrine disrupting hormone and what happens if exposure occurs?

A
  1. exposure during early life stages = may cause irreversible effects on organisms (organ development, germ cell multi-generational effects
  2. exposure during reproductive endocrine processes = affects populations (sperm and egg production/maturation, steroid hormone synthesis)
55
Q

name 3 types of EDS

A
  • pesticides
  • pharmaceuticals
  • plastics
56
Q

name two people that contributed to early evidence of EDS and what they did

A
  1. rachel carson
    - new awareness for environmental issues
    - impact of DDT on bird populations
  2. theo corbon
    - coined ‘endocrine disruption’ in 1991
    - evidence of transgenerational effects of contaminants
    - is fertility threatened because of chemicals?
57
Q

how does atrazine effect the body?

A

alters LH and FSH = effects hypothalamus or pituitary hormone secretion

58
Q

why was atrazine banned in europe? why is it still used in canada?

A
  • banned due to persistent groundwater contamination
  • canada government says evidence is inadequate, the studies conducted by government only focused on groundwater and levels were not high enough to consider a ban
59
Q

what is atrazine used for in canada?

A

herbicide

60
Q

what are endocrine glands?

A

ductless glands that secrete hormones into the blood

61
Q

are hormones always produced in ductless glands?

A

no, hormones can be secreted by small groups of cells, individual cells, or cells within various organs

62
Q

what are leptin and grhelin?

A
  1. fat cells
  2. cells within stomach
63
Q

do hormones have one production site?

A

no, secretion from an endocrine gland or cell is not unihormonal - multiple active chemicals are produced by a cell. most hormones have multiple production sites

64
Q

what is an example of a hormone that has multiple production sites and where is it produced?

A

androgens - adrenals and testis

65
Q

where can hormones be released?

A
  • into the bloodstream
  • into lymph
  • into extracellular fluids
66
Q

hormone action cannot be stereotyped:

A

it varies according to the states of the target site

67
Q

where do hormones act?

A
  • distant hormone sites
  • paracrine (nearby cells)
  • autocrine (on itself)
68
Q

the evolution of multicellular organisms made it necessary to:

A

have coordinating systems to regulate and integrate the function of different cells

69
Q

what are the two mechanisms of hormone action?

A
  1. water-soluble hormones (all amino acid based hormones except thyroid hormone)
  2. lipid soluble hormones (steroid + thyroid hormones)
70
Q

what are 3 points on water-soluble hormones:

A
  • cannot enter the target cells
  • act on plasma membrane receptors
  • coupled by G proteins to intracellular second messengers that mediate the target cell’s response
71
Q

what do lipid soluble hormones do?

A

act on intracellular receptors that directly activate genes

72
Q

what makes thyroid hormone different?

A

tyrazine residues with iodine, has special transporters that allow it to act on intracellular receptors

73
Q

mechanisms of xenobiotic disruption of endocrine system:

A
  1. hormone action exerted via binding to receptors:
    - can be initiated by chemicals if able to bind to receptor and generate hormone response
    - can be blocked by chemical if binds and blocks receptor site without induction of hormone response
  2. many other potential mechanisms:
    - hormone synthesis, secretion, transport, elimination
74
Q

what about hormones can be affected by environmental chemicals:

A

half life, target uptake, degradation, excretion

75
Q

hormones act at very ____ doses

A

low

76
Q

define non-monotopic dose-response curve:

A

dose-response relationship characterized by a curve whose slope changes direction within the range of doses tested (u or inverted u)

77
Q

define monotopic dose-response curve:

A

slope stays in the same direction as dose increases/decreases

78
Q

what type of dose response curve do hormones produce?

A

non-monotopic

79
Q

what are the consequences of receptor-mediated signalling?

A

hormones = largest effect at low doses
- saturation of receptors/effect at high doses
- desensitization and down regulation of receptors at high hormone levels
- EDCs that act via receptors are subject to same consequences

80
Q

name 2 examples of chemicals the produce non-monotopic curves in vitro:

A

cadmium, DDT

81
Q

Do hormones follow the traditional thinking of ‘it’s the dose that makes the poison?’

A

no, EDC’s cause u shaped dose response curves with adverse effects at low doses

82
Q

what was one issue of EDS testing? what do new tests do?

A

only tested at high doses and used curve to predict low dose results, thus missing the adverse effects at low doses, new testing uses lower doses designed to detect endocrine system adverse effects

83
Q

choose one group of animals and describe one chemical that affects them, how, and when:

A

mammals - 2010s - polar bears - persistent organic pollutants lead to reduced testosterone and testis size

84
Q

describe the spill that occurred in Lake Apopka:

A
  • Tower Chemical Co. spilled DDT and other contaminants
  • declared a superfund site
  • DDT and OCPs present at high concentrations in the surrounding muck farms
85
Q

what were the effects on alligators at lake apopka?

A
  • decline between 1980-1987
  • developmental abnormalities of the gonad
  • abnormal sex hormone concentrations
  • egg and embryonic abnormalities
86
Q

what is the most sensitive time for EDC effects? why?

A

development = lower doses, latent and persistent effects, increased disease risk later in life

87
Q

name 4 body systems that are impacted by EDC, one disease that impacts each one, and one chemical that affects them:

A
  1. reproductive/endocrine
    - breast/prostate cancer
    - estrogens
  2. immune/autoimmune
    - susceptibility to infectious autoimmune disease
    - dioxin
  3. pulmono-cardiovascular
    - stroke
    - BPA
  4. brain/nervous
    - alzheimer’s disease
    - lead
88
Q

what are the 3 lines of evidence that fuel concerns over endocrine disruptors?

A
  1. increased trends of many endocrine related disorders in humans
  2. observations of endocrine related effects in wildlife populations
  3. lab studies linking chemicals with endocrine effects to disease outcomes
89
Q

___ chemicals known/suspected endocrine disrupter

A

800

90
Q

how many endocrine axis disrupted by environmental contaminants?

A
  • reproductive axis
  • stress axis
  • thyroid axis
    less data for metabolism and growth
91
Q

what is the EDS definition introduced in 1999?

A

a substance that has the ability to disrupt the synthesis, secretion, transport, binding, action or elimination of hormones in an organism, or its progeny, that is responsible for the maintenance of homeostasis, reproduction, development or behaviour of an organism

92
Q

what did the endocrine disrupters testing and assessment (EDTA) task force do?

A
  • internationally harmonized guidelines
  • developed several testing and assessment strategies (mammalian, ecotoxicity tests, non-animal tests)
93
Q

what are the 3 types of OECD tests to identify EDS and what is one of the tests for each?

A
  1. in vitro - estrogen and androgen receptor binding affinity
  2. in vivo - fish screening assay
  3. in vivo (extended/transgenerational) - rodent
94
Q

what are the 3 countries implementing EDS testing?

A

US, Japan, EU

95
Q

what happened to the fish found downstream of pulp and paper mill effluent?

A
  • decreased sex steroids
  • decreased gonad size
  • delayed sexual maturity
96
Q

what is bisphenol A present in?

A

food and beverage plastic, medical devices, cleaners, personal care products

97
Q

what are negative effects of BPA in humans?

A
  • abnormal penile/urethra development in males
  • early sexual maturation in females
  • increased neurobehavioural problems
  • increased childhood obesity and adult onset diabetes
98
Q

what percent of canadians urine was BPA present in

A

90%

99
Q

what are the 3 steps that are key for gonadal determination and differentiation?

A
  1. +SRY products results in sex determination
  2. differentiation into different cell types of testis
  3. production of testosterone and MIF from testis results in male genitalia
100
Q

What were health canada’s findings on BPA in 2010? name 3

A
  1. BPA is toxic to human health
  2. current dietary exposure through food packaging uses does not pose a health risk to general population
  3. low dose effects in newborns and infants higher risk = prohibition of BPA containing baby bottles
101
Q

what were 3 of the endpoints used in OEDC 21 day fish screening assay?

A
  • survival
  • spawning success
  • vitellogenin
102
Q

aromatase inhibition ____ vitellogenin, estrogenic ____ it

A

decreases, induces

103
Q

what does linuron do and what is it?

A
  • ureic based herbicide
  • inhibits androgen mediated spiggin production in male sticklebacks and accessory sex gland development in male rats
  • is an antiandrogenic
104
Q

what does linuron do to the thyroid?

A
  • in vivo: decreased serum THs
  • in vitro: binds to TH receptor in human cells
105
Q

name 4 types of endrocrine disrupting personal care products

A

disinfectants, conservation agents, fragrances (musk ketone), UV screens (benzophenone-3)

106
Q

what compound may be responsible for increased vitellogenin in males?

A

4-nonylphenol

Environmental Toxicology (4 decks)

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