Podcast
Questions and Answers
What is a significant environmental impact of the Alberta tar sands extraction methods?
What is a significant environmental impact of the Alberta tar sands extraction methods?
What effect does imidacloprid have on aquatic ecosystems?
What effect does imidacloprid have on aquatic ecosystems?
Which of the following statements about neonicotinoids is true?
Which of the following statements about neonicotinoids is true?
What is the primary reason for the moderation of neonicotinoid application by regulatory agencies?
What is the primary reason for the moderation of neonicotinoid application by regulatory agencies?
Signup and view all the answers
How do neonicotinoids affect terrestrial insects, particularly bees?
How do neonicotinoids affect terrestrial insects, particularly bees?
Signup and view all the answers
Which of the following effects on benthic invertebrates is a direct consequence of sediment increase in aquatic environments?
Which of the following effects on benthic invertebrates is a direct consequence of sediment increase in aquatic environments?
Signup and view all the answers
What kind of regulatory action has Health Canada taken regarding neonicotinoid use?
What kind of regulatory action has Health Canada taken regarding neonicotinoid use?
Signup and view all the answers
What is one of the lesser-known effects of neonicotinoids on vertebrates?
What is one of the lesser-known effects of neonicotinoids on vertebrates?
Signup and view all the answers
What is the primary way pesticides are classified?
What is the primary way pesticides are classified?
Signup and view all the answers
Which of the following is true regarding neonicotinoids?
Which of the following is true regarding neonicotinoids?
Signup and view all the answers
How do nutrients affect the impact of neonicotinoid insecticides on freshwater communities?
How do nutrients affect the impact of neonicotinoid insecticides on freshwater communities?
Signup and view all the answers
What is one significant environmental fate of pesticides after application?
What is one significant environmental fate of pesticides after application?
Signup and view all the answers
What are the potential acute effects of neonicotinoids on honeybees?
What are the potential acute effects of neonicotinoids on honeybees?
Signup and view all the answers
What factor can modify the toxicity of neonicotinoids in ecological studies?
What factor can modify the toxicity of neonicotinoids in ecological studies?
Signup and view all the answers
Which type of action do neonicotinoids primarily exhibit in their function?
Which type of action do neonicotinoids primarily exhibit in their function?
Signup and view all the answers
What is the significant chronic effect of exposure to thiamethoxam in honeybees?
What is the significant chronic effect of exposure to thiamethoxam in honeybees?
Signup and view all the answers
How is biochemical oxygen demand (BOD) relevant in the context of pesticide impact assessments?
How is biochemical oxygen demand (BOD) relevant in the context of pesticide impact assessments?
Signup and view all the answers
What legislation governs the management of pesticides at the federal level in Canada?
What legislation governs the management of pesticides at the federal level in Canada?
Signup and view all the answers
Which of the following groups of potential toxicants are classified as organics?
Which of the following groups of potential toxicants are classified as organics?
Signup and view all the answers
What is the primary composition of Oil Sands Process Water (OSPW)?
What is the primary composition of Oil Sands Process Water (OSPW)?
Signup and view all the answers
What environmental concerns arise from increased time to metamorphosis in amphibians exposed to OSPW?
What environmental concerns arise from increased time to metamorphosis in amphibians exposed to OSPW?
Signup and view all the answers
Which metal is NOT listed among the potential toxic metals in the content provided?
Which metal is NOT listed among the potential toxic metals in the content provided?
Signup and view all the answers
What is the primary consequence of skeletal deformities observed in amphibians exposed to OSPW?
What is the primary consequence of skeletal deformities observed in amphibians exposed to OSPW?
Signup and view all the answers
What factor influences the composition and toxicity of OSPW?
What factor influences the composition and toxicity of OSPW?
Signup and view all the answers
Which of the following effects is observed in lithobates sylvaticus after exposure to OSPW?
Which of the following effects is observed in lithobates sylvaticus after exposure to OSPW?
Signup and view all the answers
What are naphthenic acids, and what role do they play in OSPW toxicity?
What are naphthenic acids, and what role do they play in OSPW toxicity?
Signup and view all the answers
How does habitat desiccation impact amphibian populations exposed to OSPW?
How does habitat desiccation impact amphibian populations exposed to OSPW?
Signup and view all the answers
Which of the following represents a legacy contaminant associated with petroleum waste?
Which of the following represents a legacy contaminant associated with petroleum waste?
Signup and view all the answers
What role do tailings ponds serve in relation to OSPW?
What role do tailings ponds serve in relation to OSPW?
Signup and view all the answers
What is a primary endpoint measured in the chronic exposure study concerning amphibians?
What is a primary endpoint measured in the chronic exposure study concerning amphibians?
Signup and view all the answers
Which phenomenon is linked to the aging of OSPW water and affects its toxicity?
Which phenomenon is linked to the aging of OSPW water and affects its toxicity?
Signup and view all the answers
Study Notes
Oil Sands Process Water
- Oil sands are located in Northern Alberta, Canada - third largest oil reserves in the world
- Unconventional oil - located directly upstream of Wood Buffalo National Park (world heritage site and is home to many indigenous communities)-- includes both in-situ and open-pit mining
- Open pit mining occupies ~1030 square km - bigger than NYC
- Oil sands process water (OSPW) = any water that has been in contact with the oil sands
- Held in large tailings ponds because there is a no-discharge policy
- Occupy over 1.3 billion cubic meters
- Small amounts of remediation occur through oxidation and photodegradation processes - no efficient or cost-effective method of remediation exists to date
- OSPW composition: 70-80% water, 20-30% solids (sand, silt and clay minerals), 1-3% residual bitumen, ~3000 elemental compositions.
- Most common: Naphthenic acids, Polycyclic aromatic compounds (PACs), Heavy metals (arsenic, boron, copper, lead, zinc), Ions (sodium, sulfate, bicarbonate, chloride)
- Composition and toxicity influenced by age, source, and location within tailings pond
OSPW Spills
- Syncrude aurora tailings pond - reports of leakages since 1973
- Suncor energy OSPW spill - estimated 350 thousand liters spilled in March 2013
- Imperial Kearl mine OSPW spill - East tailings pond leakage persisted >9 months from May 2022- Jan. 2023 - secondary spill of 5.3 million liters in Jan. 2023
OSPW Impacts - Lithobates Sylvaticus (Wood Frog)
- OSPW-contaminated wetland:
- Pollet and bendell young, 2000: decreased survival, increased time to metamorphosis, increased incidences of abnormalities in tadpoles
- Hersikorn et al, 2010: decreased survival, increased time to metamorphosis in tadpoles
- Napthenic acid fraction component:
- Gutierrez-villogomez et al, 2019: decreased survival, increased incidences of abnormalities, decreased body size in tadpoles
- Robinson et al, 2023: decreased offspring viability, decreased survival, increased time to metamorphosis, increased incidences of abnormalities
Experimental Animals
- Collected downstream of oil sands - Tower Rd, Fort McMurray, Alberta
- 90-day chronic exposure
- Following adapted OECD larval and ampibian metamorphosis assay (LAGDA)
- 7 treatments of raw OSPW (n=4) - 2 negative controls (soft water n=8, hard water n=4)
- Exposure initiation: Gosner stage 11-12
- Exposure termination: Gosner stage 42 or after 90 days
- Endpoints: hatching, survival, morphometrics, time to forelimb emergence, incidence of deformity
- Chemistry results: naphthenic acids measured (ug/L)- water hardness measured (mg CaCO3/L)
- Development results:
- accelerated time to metamorphosis in 10% OSPW
- delayed by 6 and 7 days in 40 and 80% OSPW
- Concerns: increased tadpole predation risk, risk of habitat desiccation and food availability, influence size at metamorphosis
- skeletal deformities (scoliosis in the tail and urostyle region)
- concerns: impact tadpole swimming burst speed, increased predation risk, scoliosis in urostyle region may persist past tail resorption-- elevated frequency in 20% OSPW treatment
- hind limb deformities (micromelia and distally complete but malformed segments - primary rotation of limb joints)
- concerns: decreased locomotion, shorter jumping distance, reduced endurance, increased predation risk - elevated frequency in 40% OSPW treatment
-
Conclusions
- decreased survival at 80% (9.1 mg/L NA)
- increased time to metamorphosis at 40 (6.5 mg/L NA) and 80%
- increased incidences of abnormalities at 20 (3.5 mg/L NA) and 40%
Pesticides - Key Concepts
- Pesticide: substance/mixture used to destroy, suppress, or alter the life cycle of any pest
- May be naturally derived or synthetically produced
- Can also be an organism (bacteria) or genetically modified crops
- Regulator bodies: Federal (pest control products act), Provincial (pesticide acts, drinking water legislation), Municipal (municipal pesticide by-laws)
Pesticide Fate
- Runoff from agricultural and urban areas flows directly into streams
- Transported to groundwater by recharge (rainfall/irrigation from agricultural and urban areas) - groundwater to streams during low flow periods
- Transported to atmosphere during, and after, application - atmospheric pesticides return to earth (precipitation/dry deposition) and can reach streams and groundwater
Pesticide Classification
- Classified according to target organism: insecticide, fungicide, herbicide
- Classified by chemical structure
- Classified by mode of action (receptors effected)
Neonicotinoids
- Derived in the 1990s from nicotine
- Applied onto seeds or soil prior to planting, or onto foliage
- Systemic insecticide, translocate through growing plant
- Neurotoxic, nAChR agonist
- Broad spectrum toxicity
- Formulations typically include active ingredient, silica (carcinogen), and naphthalene
- Higher affinity for, thus bind more tightly/remain bound to, nAChR receptors in invertebrates
- Continuous nervous system stimulation
- Receptor binding is irreversible so permanent effects are cumulative over time, delayed toxicity exhibited
- Acute tox testing does not detect delayed toxicity yet environmental quality guidelines rely heavily on acute tox testing during derivation process
- Mayfly's and midges are extremely sensitive to nicotinoids
Neonicotinoids - Adverse Effects on Honeybees
- Routes of exposure: dermal and oral
- Acute:
- 60-80% mortality
- Deformity incidence
-
Chronic:
- No effects on survival, growth, or hatching
- Liver gene expression:
- Imidacloprid increased estrogen and thyroid receptors
- Clothianidin decreased glucocorticoid receptor 2 (stress response)
- Thiamethoxam - no changes
-
Conclusions:
- Up to 150 ug/L individual thiamethoxam clothianidin imidacloprid - No effect on survival, hatch time duration
- Non monotonic effects on reproduction and growth measures:
- Thiamethoxam: reproductive toxicity during fertilization pulse exposure 15 ug/L
- Thiamethoxam and mixture: abnormal weight and length
Case Study - Neonicotinoid Insecticides
- Nutrients and sediment modify impacts of a neonicotinoid insecticide on freshwater community structure and ecosystem functioning
- Objectives: Pesticides are an important contributor to global freshwater biodiversity crisis - outdoor pond mesocosm experiment to investigate individual and interactive effects of pesticide and toxicity modifying factor:
- Toxicity modifying factor: when toxicity of a substance is affected by environmental chemical or biological factors
- Investigate individual and interactive effects of nutrients, fine sediments, and imidacloprid on freshwater community structure and ecosystem functioning
- Endpoints:
- Net ecosystem production (NEP) or metabolism (gross primary production)
- Estimated as difference in dissolved oxygen concentration over time
- Biochemical oxygen demand (BOD)
- Decay of organic matter in water, measure oxygen consumed by bacteria from decomposition of organic matter
- Organic matter decomposition rate
- Measure leaf litter mass before and after exposure
- Net ecosystem production (NEP) or metabolism (gross primary production)
Neonicotinoid Case Study - Conclusions:
- Single stressor strongly affected ecosystem structure and function:
-
Nutrients:
- positive effect on surface organism communities, net ecosystem production, and biochemical oxygen demand
- negative on benthic (ground) inverts biomass and community composition (shift to tolerant taxa) - possibly due to increase in surface sp resulting in decreased light to benthos and limiting benthic algal growth
-
Sediment:
- Reduced zooplankton, benthic invert, NEP - likely direct effects via physical damage to organs, reduced carbon ingestion due to ingestion of sediments
- No effect on photosynthetic biomass and phytoplankton - maybe pulses of sediment additions too short to have an impact
-
Imidacloprid:
- Negative effect on zooplankton density and NEP
- No effect on leaf decomposition (likely microbial communities dominated leaf decomposition, and microbes not affected by imidacloprid)
-
Nutrients:
Neonicotinoid Ecological Risk Assessment:
- Highly toxic to insects
- Initial application cause death in target and non-target insects
- Low level chronic exposure of insects/aquatic inverts due to soil and water exposure
- Decreasing aquatic insect/invertebrate populations
- Direct chronic exposure to some terrestrial insects that feed on plants (bees)
- Moderate to low direct toxicity to many vertebrates but:
- Perhaps minimal direct effects
- Some evidence of endocrine disruptor
- Indirect effects due to food web effects
Neonicotinoids - Health Canada Overview
- Health Canada pest management regulation agency (PMRA) reevaluations of neonicotinoids
- Registered and in use since 1990s - cancelling some use, restricting timing of application after review
- All three (Imidacloprid, clothianidin, and thiamethoxam) are still registered
Oil and Gas Related Contaminants
- Alberta tar sands - situated in the beautiful boreal forest home to indigenous peoples and a ton of biodiversity
- Methods of extraction from tar sands:
- Mining: use massive trucks
- In-situ (oil sands extraction without mining) : using hot water or steam injection to extract oil
-
Problems:
- destruction of boreal forest habitat and displacement of indigenous communities
- creates massive tailings ponds that are filled with contaminated water
- release of greenhouse gases into the atmosphere: 100% oil sands require more than double the energy to extract than conventional oil
- water contamination from leaks
- "The true cost of oil" focuses on Alberta tar sands
- Alberta tar sands are very, very large and bad - situated in the beautiful boreal forest home to indigenous peoples and a ton of biodiversity
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
