Lecture 2 Flashcards
What can you define classes of contaminants by?
- chemistry
- level of concern
- mode of action
- novelty
What does POP stand for?
persistent organic pollutants
What are the dirty dozen POPs?
- PCBs
- PCDD and PCDF
- “-drins”
- Chlordane
- DDT
- Heptachlor
- Hexachlorobenzene
- Mirex
- Toxaphene
What are the uses of PCB?
coolant/lubricant in transformers
What are the uses of PCDD and PCDF?
industrial by-product
What are the uses of “-drins”?
organichlorine insecticides
What are the uses of chlordane?
agricultural pesticides
What are the uses of DDT?
anti-malarial pesticides
What are the uses of heptachlor?
insecticides
What are the uses of hexachlorobenzene?
pesticide, industrial by-product
What are the uses of mirex?
insectice, flame retardant
What are the uses of toxaphene?
insecticide
What kind of chemicals should we worry about?
- persist in env
- resistant to metabolism
- bioaccumulate and biomagnify
- highly toxic
- PBT chemical = persistent, bioaccumulative, toxic
How can you differentiate organic pollutants?
- contain C and >1 C-H covalent bond
- C-H = low polarity, low water solubility
What are PAHs?
- Polycyclic Aromatic Hydrocarbons
How can you differentiate PAHs?
- 2or + fused benzene rings
Characteristics of PAHs?
- persistent
- natural and anthropogenic sources
- env significant PAHs range from 2 to 7 rings
What are sources of PAHs?
- pyrogenic
- petrogenic
- natural
- anthropogenic
How to differentiate pyrogenic PAHs?
- high T combustion
- unsubstituted
- high molecular weight
How to differentiate petrogenic PAHs?
- petroleum
- higher % alkylated PAHs
How to differentiate natural PAHs?
- oil seeps
- forest/grass fires
- volcanoes
- wood and animal decay
How to differentiate anthropogenic PAHs?
- oil spill, leaks
- burning fossil fuels
- cigarettes
What are the two categories of PAHs?
- low molecular weight -LMW (2-3rings)
2. high molecular weight - HMW (>3 rings)
How to differentiate LMW PAHs?
- water soluble
- not bioaccumulate
- acutely toxic
How to differentiate HMW PAHs?
- hydrophobic
- resistant to oxidation, reduction, vaporization
- accumulate in sediments and organism
- carcinogens
What are the effects of PAHs?
- metabolize to more toxic derivatives
- cause death
- impair immune system - mammals
- impair reproduction, reduce growth and dev most (not mammals)
- alter behaviour and cause blood disorders (except plants)
What are HAHs?
halogenated aromatic hydrocabons
How to differentiate HAHs?
-many congeners
What are the effect of HAHs?
similar to PAHs
- dev abnormalities
- carcinogenic
- endocrine disruption
- immune effect
- very potent
What are the sources of HAHs?
- PCBs
- Dioxin, Furans
What are the sources of PCBs?
- manufactured compounds
- dielectric fluids
- monsanto
What is the environmental fate of PCBs?
- persistent
- trasport -> absorb particles
- accumulate
How many congeners do PCBs have?
209
How to recognize Dioxins and Furans?
Dioxin = PCDD Furan = PCDF
How many congeners do PCDD have?
75
How many congeners do PCDF have?
135
What are DLCs?
dioxin like compounds
subset of HAHs
dioxins, furans and non-ortho substituted PCBs
very potent toxicant that exert toxicity through AHR pathways
What are non-ortho substituted PCBs?
ortho-substituted PCB that dont bind to AHR
Briefly describe the AHR pathway:
- contaminant binds to AHR
- induce expression of metabolic enzymes - CYP1A
- CYP1A metabolizes contaminants
Do all DLC bind to AHR path?
Yeas and they activate it
Can DLC metabolize CYP1A
not very well
What are organic pesticides?
chemicals used to kill pests
What are the categories of pesticides?
- organochlorines - DDT, chlordane
- organophosphates - monocrotophos, chlorpyrifos
- noenicitinoids - imidacloprid
Defining aspects of organochlorines?
- persistent, biomagnify
Defining aspects of organophosphates?
- inhibit acetylcholinesterase (neurotransmiter)
- extremely toxic to birds at low doses
Defining aspects of noenicitinoids?
-neuroactive insecticide
How can we differentiate Metals?
- naturally occuring
- not created nor destroyed
- human act alter
What are essential metals?
iron, zinc, copper, manganese, chromium, molybdenum, selenium
What are non-essential metals?
cadmium, lead, mercury
Define emerging contaminants:
chemicals that being manufactured for first time, not historically been considered as contaminant but now are
Are emerging chemicals rapidly increasing?
YES
