Midterm 1 Flashcards
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Pollution rank among the 10 leading causes of death worldwide.
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Pollution rank among the 10 leading ENVIRONMENTAL cause of death worldwide ( drug use, war and murder, road accidents, AIDS, ebola, alcohol use, malnutrition, etc.)
What are the routes of exposure to environmental chemicals?
- Air (respiratory tract, lungs)
- Soils (skin, GI tract)
- Water (skin, GI tract)
- Food (GI tract)
What are HPV chemicals?
High production volume
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There is only 7% of the 3000 HPV chemicals that avec the 6 basic tests needed on risk.
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Name the 6 basic tests on toxicity risk information.
- Acute toxicity
- Chronic toxicity
- Developmental and reproductive toxicity
- Mutagenicity
- Excotoxicity
- Environmental fate
What basic toxicant risk test evaluates DNA damage?
Mutagenicity
What test evaluates persistance of the chemical?
Environmental fate
What kind of toxicity describe toxicity in short term, with high single dose, soon after exposure?
Acute toxicity
Chronic toxicity testings are done on how much time?
Usually >10% of organism’s lifespan
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Chronic toxicity testing are often a lower dose\mixture
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What model do you use to define how toxic a chemical is?
Exposure-disease model
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Ecotoxicology is an integrative science
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What defines the science or study of poisons?
Toxicology
What defines the toxicity and toxicology of environmental pollutants in air, dust, sediment, soil and water, and natural toxins in the environment?
Environmental toxicology.
Often refers to human health, focuses on effects at the level of the individual.
What defines the study of fate and effect of toxic substances in ecosystems?
Ecotoxicology
It also looks at the levels of biological organization and space-time continua(effects).
What describes any substance consisting of atoms or molecules (liquid, gas or solid)?
Chemical
What describes a substance present in greater than natural concentration as a result of human activity?
Contaminant
Define Pollutant.
A substance present in greater than natural concentration as a result of human activity AND which has a deleterious effect on living organisms.
How do we call a chemical that is foreign to a biological organism?
Xenobiotic (often man-made)
What is a Toxicant?
Any toxic substance
How do we call a toxicant produced by a living organism?
Toxin
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CO2 is xenobiotic
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CO2 is not foreign to a biological organism
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Mercury can be a a chemical, a contaminant, a pollutant, a xenobiotic (?) and a toxicant.
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Chemical, contaminant, pollutant, xenobiotic, toxicant and\or toxin.
What is snake venom?
Chemical, xenobiotic, toxicant and toxin.
What’s the difference between a contaminant and a pollutant?
A pollutant infer a substance that have a deleterious effect (both are present in greater concentration than natural conditions as a results of human activity).
Pesticides are chemical, contaminant, pollutant, xenobiotic and toxicant.
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Chemical, contaminant, pollutant, xenobiotic, toxicant and\or toxin.
Which suggest human activity as a source?
Contaminant and pollutant.
Chemical, contaminant, pollutant, xenobiotic, toxicant and\or toxin.
Which are natural?
Chemicals, xenobiotic, toxicant and toxin.
Chemical, contaminant, pollutant, xenobiotic, toxicant and\or toxin.
Which suggest that the substance is harmful?
Pollutant, toxicant and toxin.
What years refer to the ‘‘age of darkness’’ in terms of environmentalism?
1930s-1950s
What time of chemicals were associated with with cross-bill in double-crested cormorants (birds in the Great Lakes, 1970s)?
Organochlorines (PCBs)
Were banned in North American in 1977.
Name an ongoing problems that faces actual ecotoxicology.
Endocrine disruption hypothesis (Theo Colborn): Are we threatening our fertility, intelligence and survival?
How do we call chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological and immune effects in both humans and wildlife?
Endocrine disruptors (EDCs)
How do we study and regulate chemical use’s in modern ecotoxicology?
- Improved testing and regulation
- In vitro methods
- Subtle effects of chronic exposures (epidemiological approach)
Lois Gibbs key toxicants?
Chlorinated hydrocarbures residues HAHs (PCBs?)
December 3 1984 key toxicant?
Bophal disaster: Organic pesticide (methyl isoyanate)
Agent orange key toxicant?
TCDD pesticide (DLCs)
What happened on march 24 1989?
Exxon Valley Oil spill (PAHs petrogenic)
What happened on April 20 2010?
Deepwater Horizon spill oil (PAHs petrogenic)
What happened on march 11 2011?
Japan earthquackl and tsunami (radiation)
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Risk is the possibility of harm.
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Risk is the proBability of harm (how dangerous). Risk = Exposure x Hazard
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Hazard determines the toxicity
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The possibility of harm.
What the dilution paradigm?
The solution to pollution is dilution
What means NIMBY?
Not in my backyard
What’s the boomerang paradigm?
What you throw away can come back and hurt you
What’s the precautionary principle?
A duty to prevent harm, when it is within our power to do so,, even when all the evidence is not in.
-Absence of scientific evidence to take precautions does not mean that precautions shouldn’t be taken
What are PBTs?
Persistent Bioaccumulative Toxic (level of concern class)
What are POPS?
Persistant Organic Pollutant (level of concern class)
Name 2 types of toxicants that are classified according to their mode of action.
Endocrine disruptors (EDCs) Neurotoxicants
Name a toxicant classified on its organic chemistry.
PCBs : polychlorinated biphenyls
What do we worry about chemicals?
PBT + resistant to metabolism
Name 3 types or organic contaminants.
What are their characteristics?
- PAHs: polycyclic aromatic hydrocarbons
- HAHs: halogenated aromatic hydrocarbons
- Organic pesticides
- At least <1 C-H
- Low polarity, low water solubility (increases with O)
- Fate depend upon chemistry
- Natural and anthropogenic sources
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PAHs = 3 > fused benzene rings up to 7 and are persistent
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PAHs = 2 > fused benzene ring up to 7 and are persistent
What PAHS has 2? 5? 7? Benzene rings
2- Naphthalene
5- Benzo-(a)-pyrene
7- Coronene
How to molecularly identify petrogenic PAHs ?
Gr alkyle (CH3)
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Pyrogenic PAHs have LMW
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Pyrogenic PAHs have HMW
Name natural sources of pyrogenic PAHs
Forest\grass fire, volcanoes, wood and animal decay, and forest\grass fires.
Name anthropogenic sources of petrogenic PAHs
Oil spills, burning of fossil fuels, cigarettes.
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HMW PAHS molecules are more likely to be carcinogens that be acutely toxic and have more than 3 rings.
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What are the 3 types of HAHS?
Name characteristics.
- Dioxins
- Furans
- PCBs
- Developmental abnormalities
- Carconogenic
- Endrocrine disruption
- Immune effects
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PCBs are natural, like PAHs
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PCBs are manufactured compounds , like found on dielectric fluids, that were banned.
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PCBs are PBTs
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Dioxins and furans are manufactured.
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Products of hight temperature incineration
How to recognize dioxins and furans?
Dioxins = 2 benzene rings link by 2 O
Furans: 2 benzene ring linked by a furan (1 O)
How are part of DLCs? What are their common point?
Dioxins, furans and non-ortho (no Cl on 2, 6 ,2’ or 6’) PCBs (all HAH except ortho PCBs).
They all bind to AHR
What’s the name of the enzyme metabolized when contaminants bind to Aryl Hydrocarbon Receptor?
CYP-1A
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PAHs bind to AHR
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PAHs are well metabolized by CYP-1a, but the product of metabolism can be carcinogenic.
Name 3 classes of pesticides.
- Organochlorines (PBT)
- Organophosphates : inhibit acetylcholinesterase (neurotransmitter) ex: monocrotophos
- Neonicotinoids ex:imidacloprid
What killed hawks in Argentina?
Monocrotophos, an organophosphates (toxic to birds)
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Generally speaking, metals are promoter of reduction.
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Oxidation (most metals are positive)
Metals can bind on what group on proteins?
Sulfhydryl (thiol) groupe on methionine and cysteine..
Name 3 non-essential metal.
Cadium, lead, mercury.
2 types of metals?
Essential, non-essential.
What classes of chemical mercury is belonging?
Neurotoxicant (methylated form aka methylmercury biomagnifies, fishes).
How do we calls chemicals that are manufactured for the first time and or have not historically been considered as contaminant?
Emerging contaminants ex: flame retardants
Where can we find classes of emerging contaminants?
Pharmaceuticals, personal care products, flame retardants, nanomaterial, plasticizers and rare earths elements.
What are BFRs and OPFRs?
Brominated Flame Retardants and Organophosphate Flame Retardants.
What defines where contaminant originates or is released from?
Source
What do we define any single identifial source of pollution from which pollutants are discharged?
Point source (ex: pipe, ship, factory)
Whats a non-point source?
From diffuse source, mainly due to precipitation. ex: fertilizers
What happens to a chemical once it enters the environment is called…
Fate
What are the 3 factors influencing chemical fate?
- Environment conditions
- Properties of chemicals
- Pattern of Use
Name 3 contaminant key physical-chemical properties
- Solubility in water (Kow)
- Vapor pressur
- Susceptibility to degradation\transformation
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Kow>1 = lipophilic, usually non-polar large molecules (many Cl, C-H)
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log Kow <1 = hydrophobic
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log Kow < 0 = hydrophobic . Kow <1 =hydrophobic
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HMW PAHs are hydrophilic
F LMW PAHS (2-3) are hydrophilic) HMW PAHS (>3 ) are hydrophobic
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More chlorine atoms = high Log Kow More rings = higher Log Kow
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How do we call the phenomenon that describes contaminants that are transported from warmer to colder regions?
Global Distillation or Grasshopper Effect
How can you absorb chemicals?
Inhalation, dermal contact, ingestion, maternal transfer
Whats the name of a biological process which transform xenobiotics into more water soluble forms that can be excreted?
Biotransformation(liver)
How do we call the biotransformation analogy?
Hitch and Trailer
Name 3 types of phase 1 reactions.
- Hydrolysis
- Reduction
- Oxidation
Epoxide hydrolases do reaction of…
Hydrolysis
Cytochrome P450, alcohol dehydrogenase and aldehyde dehydrogenase are reaction of…
Oxidation
What’s the caffeine metabolite toxic to dog? What enzymes is involved, and in what phase of biotransformation?
TheoBromine, CYP1A2, Phase 1 biotransformation
What enzymes that cant keep up is the cause of hangover?
ALDH Acetaldehyde dehydrogenase (oxidation)
Does MeHg biomagnify with a log Kow of 2.54?
Yes: binds to protein thiols
Whats the problems with PAHs and AHR?
PAHs are metabolize to carcinogenic epoxide.
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Species that have an AHR that is more easily activated are more sensitive to DLCS
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AHR pathway is ineffective (carcinogenic metabolites) and dangerous (stays on).
What defines build up of concentration in an organism to a concentration that is higher than the concentration in the medium?
Bioconcentration
What defines build-up of contaminant within the tissues of an organism (includes bioconcentration and dietary intake)?
Bioaccumulation
Increase in concentration of contaminants as you move up the food chain is…
Biomagnification
What are the 3 Assumptions of dose-response curves?
- Response is due to the chemical
- Magnitude of response associated with dose
- Quantifiable method to assess response
Whats the name of the real amount of chemical an org was exposed to?
Actual
Whats the name of the quantity you think the org have been in contact with?
Nominal
How to we call the concentration of a contaminant required to produce a certain effect?
Potency
How do we call the magnitude of the response?
Efficacy
What is NOAEL, or LOAEL?
No observed adverse effect level
Lowest observed adverse effect level
Whats the name of a beneficial effect resulting from exposure to low doses of a toxic agent?
Hormesis
Whats linear no threshold model?
Assumes damage is directly proportional to dose
A biological response to a chemical that gives a measure of exposure and sometime a toxic effect is a…
Biomarker
What are the tree characteristics of biomarkers?
- Biological
- Measurable (quantitaive)
- Marker for something else
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Gold Standard biomarkers can be used to diagnose a problem without chemical data
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What standard need more research to be linked to specific exposures or outcomes?
Bronze ex: thyroid hormones
Whats vtg
Estrogenic compound vitellogenin , egg yorlk precursor protein not normally found in male fish.
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Estrogenic binds to Estrogen Receptor ER and induces transcription of vitellogenin VTG
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What is the presence of female gonadal tissue in male gonads or reverse?
Intersex
What is imidacloprid?
A neonicotinoid organic pesticide
Do imidacloprid bioaccumulate?
No
Name a characteristic about imidacloprid
Sensitive to photolysis
What targets imidacloprid?
nAChR
Nicotinic AcetylCholine Receptor (neurotransmitter)
Whats ERA?
Environment Risk Assessment = prediction of the likelihood of harmful effects occuring to prganisms exposed to environmental stressors
What describes exposure assessment?
Type, magnitude, frequency route and duration of exposure
ex: Neonicotinoids in seeds, EDC in water
What assessment quantify relation between dose and response?
Hazard
