Midterm 2 Flashcards
Recent studies show presence of pesticides in human blood. What are the concentrations and what is the kind of pesticide?
2-5 ug/L in human blood for DDE
List 6 Federal Legislations for Managing Pesticides
- Pest Control Act
- Food and Drug Act
- Canadian Environmental Protection Act
- Fisheries Act
- Migratory Birds Convention Act
- Species at Risk Act
List 2 Provincial or Territorial Legislations for Managing Pesticides
- Pesticide acts and associated regulations
- Drinking water legislation
What are the Municipal legislations for Managing Pesticides
Municipal pesticide by-laws
Define Pesticide with examples
Any substance/mixture of substances used to destroy, suppress, or alter the life cycle of any pest.
May be naturally derived or synthetically produced.
May also be an organism (e.g. Bacillus thuringiensis, genetically modified corn…)
Most Common Types of Pesticides Include
Bactericides, fungicides, herbicies, insecticides, rodenticides
Define Systemic Insecticide
Translocated through growing plants
Define Neurotoxic
Nicotinic acetyl choline receptor antagonist. Toxic to nerve tissue.
Characteristics of Imidacloprid
Bayer Crop Science
Half life: 30-162 days
Soil: 1-2 years
Octanol water partition coefficient (log Kow): 0.57
Highly water soluble 610 mg/L at 20 degrees
Neonicotinoid Mode of Action
Binds to nAChR in postsynaptic neuron (normally scetylcholine binds to and degraded by acetyl choline esterase) but nAChR not irreversibly bound.
Acts as false neurotransmitters
Causes continuous activation of receptor leading to symptoms of neurotoxicity
Also include carcinogens like silica and napthalene
Acute toxicity testing does not detect delayed toxicity yet the environmental guideline rely heavily on _________ toxicity test data during ____________ process
Acute ; derivation
Factors in the Reptile Extinction Rate
Heavy use of pesticides, urbanization and climate change
Wetlands in Canada are deteriorating because…
Increased anthropogenic effects: expansion and intensification of agricultural areas (chemical fertilizer and pesticide pollution, sedimentation and loss of vegetation)
Lab species in standard toxicity tests are not always the most sensitive to neonicotinoids. Why is this important?
Wide range of differences in sensitivities between invertebrate taxa and environmental quality guidelines are based on data for lab species; do not accurately reflect the toxicity in animals that may be impacted in the real world
Species Sensitivity Distribution (SSDs)
More useful for deriving environmental qquality guidelines.
Models of the VARIATION in SENSITIVITY of species to a particular stressor and are generated by fitting a statistical function to the proportion of species affectes as a FUNCTION of toxicant conc or dose
What is the Canadian Water Quality Guideline for the protection of aquatic life (CCME)
0.23 ug/L
3 Basic Components of the Endocrine System
- Endocrine Gland (like the hypothalamus) which secretes hormones and effects distal targets
- Hormone which is the chemical product and is released upon stimulation
- Target Organ (like ova or testes) which expressed the hormone-specific receptors and shows biological responses
Pathway of Hormones
Hypothalamus -> Pituitary -> Parathyroids -> Thyroids -> Adrenals ->Pancreas -> Ovaries/Testes
In depth hormone pathway
Higher brain centers -> Hypothalamus -> Thyroid Releasing Hormone -> Pituitary -> Thyroid Stimulating Hormone -> Thyroid -> T4, T3 -> Target Issues
Examples of Hormones that control Major Physiological Processes
Thyroid Endocrine Axis: Regulates development/differentiation
Neurons, muscle and Sertoli cells: metabolism and growth
What is an Endocrine Disrupting Substance?
Exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an INTACT organism, its progeny, or (sub)populations.
(In vitro not enough evidence to deem something an eds!!!)
Characteristics of EDS
Effects at low concentrations (pg/L-ng/L)
Mixtures can produce additive effects at individually negligible concentrations
Early life exposure may cause irreversible effects like organ development
Exposure during reproductive endocrine processes affect population (sperm/egg production or maturation…)
What is Biotransformation?
The sum of the chemical reactions that occur within the body to alter the structure of a xenobiotic/endogenous compound, carried out by enzyme systems.
It converts xenobiotics into more hydrophilic, less toxic forms; decreasing intracellular concentration via excretion.
2 ways Toxicity can be Affected
Detoxification (conversion into a less toxic form)
Bioactivation (conversion into a more toxic form)
