Toxicology Pt. 1 Flashcards
toxicant
man made poison introduced into the environment
toxin
natural poison produced by a living organism
toxicity
the amount or degree of toxin/toxicity it takes to damage an organism
toxicosis
disease state induced by the toxin/toxicant
nanotoxicology
Branch of toxicology which studies the toxicity of
nanoparticles (ultrafine particle between 1-100 nanometres in diameter)
NOAEL =
No observed adverse effect level
LOAEL =
Lowest observed adverse effect level
LC50
Lethal Concentration 50- concentration required to kill 50% of the
population
LD50
Lethal dose 50- dose at which 50% of population dies
acute/subacute/chronic toxicology timelines
acute: happens from an exposure within 24 hrs
subacute: w/n 24hrs-1 month
chronic: w/n 1-3 months
what is a toxic endpoint?
-measures of relative toxicity of a compound based on studies conducted to determine how
dangerous a substance is
-endpoints can include mortality, behavior, reproductive status or physiological or biochemical changes
Developmental/reproductive toxicology (DART) study purpose
ensure the safety of new life-saving drugs before they go on the market.
-used to develop safety guidelines to reduce exposure
risks for different populations, including pregnant women, infants and young children.
-studies fall into 2 main categories: developmental (pre-natal development) and reproductive (looks at all aspects of fertility)
Which agencies have guidelines for DART studies?
FDA, EPA
The toxicity tests that are required in the U.S. are dictated by test guidelines put forth by the
International Conference on Harmonization (ICH)
Three DART tests are required for small molecule pharmaceuticals:
1) Embryo-Fetal Development (EFD)
2) Fertility and Early Embryonic Development (FEED)
3) Pre- and Postnatal Development study (PPN)
the EPA requires DART testing for product registration of pesticides
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Toxic Substance Control Act
EPA law that regulates testing requirements for industrial chemicals.
-EXCLUDES food, drugs, cosmetics, pesticides
Most common type of herbicide resistance
Target-site resistance
(herbicides target a specific site in a plant to bind and shut it down in order to kill the weed. Plants can adapt to prevent this binding ie. via a change to an amino acid residue chain)
Non-target site resistance aka metabolic resistance
occurs when weeds develop the ability to rapidly metabolize the herbicide before it can cause significant biotoxic effects
how to prevent herbicide resistance in plants
tank-mix multiple herbicides in each application to reduce probability plant is resistant to both
DNA adduct
segment of DNA bound to a cancer-causing chemical
-used as biomarkers of
carcinogen exposure, but necessarily cancer
ADME =
Absorption, distribution, metabolism, excretion
(describes pharmacokinetics)
Absorption
describes the journey of drug traveling from the site of
administration to the site of action
Distribution
describes reversible transfer of the drug from one location to
another within the body
Metabolism
conversion and breakdown of the drug within the body
Excretion
process by which metabolic waste is eliminated from an
organism
OSHA =
Occupational and Safety and Health Administration
-a division of the US Dept of Labor
-concerned with making sure employers provide their workers a place of employment free from recognized hazards to safety and health, such as exposure to toxic chemicals, excessive noise levels, mechanical dangers, heat or cold stress, or unsanitary conditions
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
provides for federal regulation of pesticide distribution, sale, and use
Resource Conservation and Recovery Act (RCRA)
gives EPA the authority to control hazardous waste from the “cradle-to-grave” including the generation, transportation, treatment, storage, and disposal of hazardous waste
Clean Air Act
federal law that regulates air emissions from stationary and mobile sources.
-authorizes EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and public welfare and to regulate emissions of hazardous air pollutants
Clean Water Act
establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters
-makes it unlawful to discharge any pollutant from a point source into navigable waters unless a permit obtained
Safe Drinking Water Act
authorizes EPA to establish minimum standards to protect tap water and requires all owners or operators of public water systems to comply with these primary (health-related) standards
Concentrated animal feeding operation (CAFOs) are considered point sources
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Conditions to be considered a Concentrated animal feeding operation (CAFO)
-animals are stabled or confined and fed or maintained for a total of 45 days or more in any 12-month period
-crops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA aka Superfund)
provides a Federal “Superfund” to clean up uncontrolled or abandoned hazardous-waste sites as well as accidents, spills, and other emergency releases of pollutants and contaminants into the environment
Pollution Prevention Act
focused industry, government, and public attention on reducing the amount of pollution through cost-effective changes in production, operation, and raw materials use.
-Pollution prevention includes practices that increase efficiency in the use of energy, water, or other natural resources, and protect our resource base through conservation
National Response Center
the designated federal point of contact for reporting all oil, chemical, radiological, biological and etiological discharges into the environment, anywhere in the United States and its territories
-staffed by the Coast Guard
Federal Food, Drug, and Cosmetic Act (FFDCA)
atuhorizes EPA to set tolerances, or maximum residue limits, for pesticide residues on foods
Food Quality Protection Act (FQPA)
requires that EPA:
-make a safety finding when setting tolerances, i.e., that the pesticide can be used with “a reasonable certainty of no harm”
-use this new safety standard to reassess, over a 10-year period, all pesticide tolerances that were in place
-use an additional tenfold safety factor when setting and reassessing tolerances for children
-consider aggregate risk from exposure to a pesticide from multiple sources
