Midterm 3 Flashcards
What are the effects of Atrazine?
- impairs gonad development of males/females
- effects reproduction
What are the results of an imbalance in steroid levels?
- causes adverse effects
- eg. Frogs gonadal malformations (ovotestis)
When was Atrazine banned from use in Europes?
-in 2004 due to persistent groundwater contamination
What is Atrazine used for?
- broadleaf weed control on crops
- including corn and low bush blueberries
Is Atrazine found in BC?
Detected in 71-75% of waterways sampled in BC
Is Atrazine banned in Canada? (BC)
-it was briefly banned in BC, but in 2012 is was reapproved for use on agricultural crops
What amounts of atrazine are found in fresh water and drinking water in Canada?
- DW: 5 ug/L
- FW: 1.8 ug/L
What is endocrinology?
-the study of the endocrine glands and their secretions (hormones)
What are endocrine glands?
-ductless glands that secrete hormones into the blood
Why is the endocrine system necessary for multicellular organisms?
-the evolution of multicellular organisms made it necessary to have coordinating systems to regulate and integrate the function of different cells
What are two mechanisms of hormone action?
- Water-soluble hormones
- 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 - Lipid-soluble hormones
- act on intracellular exceptions that directly activate genes
What is a hormone?
A regulatory substance produced in an organism and transported in tissue fluids such as blood to stimulate specific cells or tissues into action
What are some expanded definitions of hormones?
- secretion from an endocrine gland or cell is not unihormonal - multiple active chemicals are produced by a cell
- hormones do not always act on distant target sites. They can have paracrine or auto rinse effects
- hormones are not only secreted into the bloodstream, they can be released into lymph or extracellular fluids
What is a hormonal mimic?
-binds to receptor and induces a hormonal response
What is a hormonal antagonist/block?
- binds to receptor and does not allow a hormone to bind
- hormonal response is blocked
What are potential mechanisms of Xenobiotic Endocrine Disruption?
- hormone synthesis
- secretion
- transport
- elimination
What are adverse effects of endocrine disruption on humans?
- reduced fertility
- altered brain development
- reduced sperm quality
What are adverse effects of Endocrine Disruption on wildlife?
- altered growth
- decrease reproductive success
- delayed or altered development
Will an estrogen mimic have an effect at low levels?
Yes
What kind of dose responses do hormones produce?
-non-mono tonic dose responses
What is an EDC?
Endocrine disrupting chemical
What is the most sensitive time for EDC effects and why?
- development stage
- developmental effects are different from adult effects
- lower doses
- latent and persistent effects
- increased disease risk later in life
What are traditional toxicology endpoints?
- gene mutations
- weight loss
- death
- tested in high doses/concentrations
Where are the new testing regimes developed by the OECD implemented?
- EU, US and Japan
- designed to detect endocrine system adverse effects
- test at lower doses than traditional tests
What are outcomes of chemicals with endocrine activity?
- may act at low doses
- should be expected to have non-mono tonic dose responses
- will have tissue specific and time specific effects
- will show different effects and dose responses during development relative to adults
- will likely not have a threshold
What are the implications of EDC for human health?
-chemicals with endocrine activity may be either missed completely or have a “safe level” that is not protective of human health
What were the effects of the EDC case study on reptiles
- decline of alligators between 1980-1987
- developmental abnormalities of the gonad
- abnormal circulating sex hormone concentrations
- egg and embryonic abnormalities
- reptile sex is determined by temperature
What system does BPA primarily effect?
-reproductive/endocrine
What are the effects/diseases that result from BPA?
- breast/prostate cancer
- endometriosis
- infertility
- diabetes/metabolic effects
- early puberty
- obesity
What are the 3 lines of evidence that fuel concerns over endocrine disrupters?
- increased trends of many endocrine-related disorders in humans
- observations of endocrine related effects in wildlife populations
- lab studies linking chemicals with endocrine effects to disease outcomes
How many endocrine axes are disrupted by environmental contaminants?
Evidence for:
- reproductive axis (estrogenic/anti-estrogenic, androgenic/anti-androgenic)
- stress axis (anti-adrenal)
- thyroid axis (tyroidogenic/anti-thyroidogenic)
Less data for:
-metabolism and growth endocrine processes (digestive, pancreatic)
Is there EDS testing in Canada?
-no mandatory testing of EDS by any government departments
What countries implement EDS testing?
- US, Japan, EU
- now require or shortly will require, information about the endocrine disrupting effects of chemicals
What were the effects of fish downstream of pulp and paper mill effluent?
- decreased sex steroids
- decreased gonad size
- delayed sexual maturity
What does the endocrine system control in reproduction?
- gametogenesis
- behaviour/courtship
- secondary sex characteristics
- spawning
What occurred when there were improvements in pulp and paper mill effluent quality? What year did this occur in?
Environmental Effects Monitoring (EEM)
1993
What is Environmental Effects Monitoring (EEM)?
-pulp mill effluent monitoring program: goals based on Fisheries Act, protect fish, fish habitat and the use of fisheries resources
What is the testing for Environmental Effects Monitoring (EEM)?
- Every 3 years, but if no effects than every 6 years:
- sub lethal toxicity testing of effluent: fish early life stage development, reproduction of an invertebrate, algal growth inhibition and reproduction
- biological monitoring: fish survey(condition factors, LSI, GSI), benthic invertebrate community survey
What region does EEM monitor?
-sub-tidal region
When was the last change to mill processes in Canada?
In the 1990s
Where is Bisphenol A (BPA) present?
-food and beverage plastic, medical devices, cleaners, personal care products, dental fillings, vinyl shower curtains
Where does BPA act?
It is a membrane bound estrogen receptor
What are human health effects of BPA?
- abnormal penile/urethra development in males
- early sexual maturation in females
- increased neurobehavioral problems (ADHD, autism)
- increased childhood obesity and adult onset diabetes
- declines in sperm counts
Why does BPA still cause effects even though it is excreted rapidly?
-ubiquitous and constant exposure
What kind of toxin is BPA?
A plasticizer
What are the standardized endpoints of a 21 day fish reproductive screening assay?
- survival
- secondary sex characteristics
- vitellogenin
- GSI
- Gonad Histopathology
- Spawning Success
- E and T concentrations
What are additional endpoints of a 21 day fish reproductive screening assay?
- egg 7 day survival, deformity
- estrogen receptor, steroidogenic enzyme, gene expression
What is Linuron?
-Uriel based herbicide
What converts testosterone to 17B-estradiol?
Aromatase
What are pharmaceuticals?
-prescription, over the counter veterinary therapeutic drugs to prevent or treat human and animal diseases
What are personal care products?
-products mainly to improve quality of life
Where do PPCPs go unintentionally?
- discharged mainly in sewage into aquatic environments (sediment, water, fertilizer applications)
- does not get properly processed in phase 3 sewage treatment
What was the response and responsible compounds of the sewage effluent example?
Response: increased vitellogenin in males, altered testis development
Responsible Compounds: estradiol, estrone, ethynyl estradiol
What did the chronic exposure of fathead minnow to low concentrations of potent 17-ethynlestradial lead to?
- feminization of males through the production of vitellogenin mRNA and protein
- intersex in males
- altered on genesis in females
- near extinction of the species
When we are looking at mining toxicants what level of impact are we focusing on?
Community Structure
- reductions/increases in community structure
- biodiversity changes
What are the base metals mined in canada?
-copper, zinc, lead, nickel
What precious metals are mined in Canada?
-gold, platinum group metals, silver
What is removed in open pit mines?
- ore (high in desired metals)
- waste rock (doesn’t have desired metals present)
What is a contaminant where blasting is used?
- Nitrogen
- involved in blasting and often becomes a large contaminant in the mining area
What are the 3 stages of a modern mine life cycle?
- Planning & construction (clearing/blasting)
- Operations (wastewater & tailings management)
- Closure (site clean-up, maintenance, monitoring)
What does MMER stand for?
Metal mining effluent regulations
What is the overall goal of the MMER?
-to minimize the effect of mine effluent on waters frequented by fish
What provision requirements are included in the MMER?
- discharge limits
- acute lethality
- environmental effects on fish, fish habitat and fisheries resources
Mines that are subject to the MMER may deposit an effluent that contains a deleterious substance if?
- The concentration of the deleterious substance in the effluent does not exceed authorized limits
- The pH of the effluent = 6-9.5
- The effluent is not acutely lethal (kills less than 50% of rainbow trout in 100% concentration over 96 hour period)
What does the EEM do (in regards to MMER)
Provides framework and methods for collection of data on fish health, benthic invertebrate community structure, water quality and effluent monitoring
What were the contaminants discharged in industrial effluents at Howe Sound?
- organochlorines
- metals (copper, zinc and iron)
- sulphuric acid
- mercury
What was produced at the faro mine complex?
-lead, zinc, silver and gold mine
When was the faro mine operational?
1969-1998
In the faro mine what ended up in the surface water?
Iron, manganese, zinc, sulfate
At the faro mine when was dissolved zinc in water at its highest?
-ice covered water
What vertebrates were monitored at the faro mine and what is one endpoint?
- arctic grayling & slimy sculpin
- CPUE, Length, Condition
What invertebrates were monitored at the faro mine? What is one end point measured?
Benthic Invertebrates:
-Bray-Curtis Index
What impacts do oil spills have on avian species?
- stress
- thermoregulation and metabolism
- flight and swimming performance
- reproduction
- behavioural effects
What is eDNA?
- DNA released to the environment
- Collect via water/sediments/soil
- Isolate and analyze DNA for target taxa
- See if target species is present
Why are Biological Surveys Conducted?
Regulatory: environmental risk assessment, SARA, commercial recreational and aboriginal fish protection
Conservation Biology: species inventory, habitat mapping
Invasive Species: early detection, confirm eradication
What are the advantages of eDNA?
- less invasive
- can detect low amounts
- quick to sample
- cost effective
- accurate (no in field experts needed)
- reduced observer bias
- expanded survey window
What are the limits of eDNA testing?
- Only detects presence of target DNA
- Cannot determine number
- eDNA degrades
What is vitellogenin?
-protein present in the blood, from which the substance of egg yolk is derived
What is acid mine drainage?
-when ore is exposed to rain/water/snow and you get sulfuric acid forming
Why is atrazine banned in Europe and not in Canada?
The acceptable level is less in Europe (0.1) than in canada (5)
