Organics Flashcards
What are organic toxicants?
Carbon based compounds
Petroleum hydrocarbons (PHC)
Crude oil - unrefined, make of aromatic and aliphatic compounds of chains from C5 - C50, highly lipophlic
What is fraction 1 PHC used for?
Volatile fraction used for gasoline
What is fraction 2 PHC used for?
To produce kerosene, creosote, diesel
What is fraction 3 PHC used for?
Used to produce diesel and lubricating oils
what is fraction 4 PHC used for?
Used for waxes, bitumen/asphalt/tar
Polycyclic aromatic hydrocarbons (PAHs)
Two or more fused aromatic rings, produce when organic material is burned (combustion), natural and anthropogenic sources.
- Low solubility
- Lipophilic
- Some are pryogenic (pyrolytic), petrogenic or biogenic
How can PAHs affect vertebrates?
Relatively unreactive, metabolic pathways can alter reactivity, can be carcinogenic
Creosote
Derived from coal tar, made of PAHs, uned to treat against wood root, cans been used medicinally and as meat preserver
Where are PAHs found in the environment?
MAin sinks are soils and sediment
Polychlorinated Biphenyls (PCBs)
Very stable, inflammable, non conductive, man-made, insulating fluid, hydraulic fluid, flame retardant, persistent and hydrophobic, all anthropogenic, chronic effects on endocrine system, carcinogenic
Dixoins and Furans
Chlorinated organics, persistent and hydrophobic, not metabolized, some toxic to mammals, interfere with endocrine system and carinogenic
-Metal refineries, pulp and paper mills, manufacturing
Polychlorinated dibenzodioxins (PCDDs)
Dioxins
Polychlorinated dibenzofurans (PCDFs)
Furans
Chloracne
Acne-like eruption of cysts form the exposure (initially chlorine) halogenated aromatic compounds, inflammatory response to dioxins
Tetratogenicity
The ability to cause defects in fetal development (cleft palate)
Agent orange
Chemical herbicide and defoliant used during Vietnam War. Dioxins have persisted in Vietnam ecosystem, biomagnifing and accumulating in groundwater
Pesticides
Any biological or chemical agent that kills unwanted pests - plants or animals
What is the ideal pesticide?
- Kills quickly
- Persistent to be effective, breakdown into non-toxic products
-Cheap to manufacture - without unwanted contaminating compounds - Not yet invented
Why are pesticides problematic?
Because many biological processes are highly conserved
DDT, methoxychlor, chlorinated cylodienes and HCH are . . .
Neurotoxins, persistent, low water solubility, lipophilic, volatile
- Can interfere with vertebrate endocrine, nervous and immune systems
DDT
First modern chemical pesticide, subject of “Silent Spring”, penetrates waxy cuticle of insects & kills nerve cells by disrupting Na+ balance.
- less bio-available to vertebrates
- still used in countries where malaria and leishmania is endemic
What is DDT calculated as?
Summation of DDT isoforms, DDE and DDD
What did WHO aim to eradicate using DDT?
Malaria
