Final stretch Flashcards
Missed lecture 17
okok chill shawty
What is a flame retardent?
A substance added or a treatment applied to a material to suppress, or significantly reduce or delay combustion
-brominated flame retardents
Why are C-Brs used over other halogenated compounds in flame retardents?
C-F and C-Cl bonds are too strong, lowering the capacity to trap free radicals and slow combustion - also more persistent in the enviornment
C-I bonds are too weak / unstable, will disintegrate before encountering fire
C-Br is middle ground
3 subgroups of BFRs
TBBPA - used in electronics and circuit boards
80% reactive - 20% additive
Hexabromocylododecane (HBCD) - legacy
- used inelectronics / thermal insulation
Polybrominated diphenyl ethers (PBDEs) - legacy
- used in cushions, sofas, electronics
What is the difference between a reactive and additive TBBPA?
Reactive means they are integrated as part of the polymer
Additive means they are just added in and not part of larger polymers - more capacity to leach out of substance
How are BDE chemical properties affected by increasing molecular weight (increased bromination)
Increasing molecular weight
- decreases solubility (more lipophilic)
- less volatile
- greater affinity to organic carbons
Major exposure pathways for BRFs?
Ultimately comes from consumer products which can end up inhaled or in food, waste systems can become contaminated as well
- those dealing with electronic recyling / waste
- breast milk while nursing is a major exposure pathway
What is found with PDEs in BC?
found higher concentrations nearest to discharge sites
- concentrations in biota were positively correlated with concentration in sediment
Human exposure to PBDEs?
- breastmilk
- maternal transfer to fetus
- diet
- indoor air, house / office dust
- occupation (electronic waste / recycling)
What type of food will have the highest concentrations of PBDEs?
Dietary supplements like fish oil supplements
- poultry liver and fat
How doe BDEs effect human health?
Liver as a target organ - penta/octaBDE
- increased ezymatic activity of phase 1 and 2 enzmyes, increases liver weight, hisopathological changes
- developmental neurotoxicity - likely due to disruption in thyroid hormone signalling
- endocrine disruption
Thyroid toxicity of BDE
Thyroid - regulates homeostatic processes
- metabolism, temperature regulation, in utero growth, neonatal development
- hydroxylated PBDEs are similar to T4/thyroxine - potential interaction with similar targets - T3/T4 have 3/4 iodines, brominated compounds are similar
T4 is more common, but T3 is the primary active form of the hormone
- T4 are bound to thyroid transporting protiens to move in the plasma - however PBDEs have higher affinity to transporting hormones than T4 which leads to disruption of thyroid signalling
Missed oil lecture
What was diethylstilbesterol DES?
One of the most famous chemicals resulting in sever human impact
- used for pregnant women to prevent miscarriage
-later found to cause vaginal cancers at high rsks
- caused genital tract abnormalities and infertility
- affects estrogen responsive tissue
Whats up with tributyl tin?
organometallic biocide used in ship paint
- served as a replacement to DDT
-was used as a disinfectant in jerseys
- affected mollusc populations among main shipping routes
- masculinization of female snails
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What were the endocrine effects of municipal effluents?
- in 1990s found changed gonadal phenotypes in male fish downstream of wastewater treatment plants
- phenotypes manifested as the occurrence of female tissues in testes - intersex
- up to 100% of fish
- main effects on male roach
What was up with the semen quality impacts
early 2000s studies showing that sperm quality has decreased
- possibly linked to pesticide exposure - affects farmers the most
what was up with BPA?
Bisphenol A
- plasticizer used to harden plastics
- 6 billion pounds per year used in consumer products including baby products
- negative reproductive effects such as PCOS
- weak estrogen mimic
- CAD banned in baby products
Two functions of the endocrine system?
coordinate homeostasis in the body
allow communication among organs
4 physiological processes regulated by the endocrine system?
- reproduction
- growth
- maintenance of the internal environment
- energy availability
4 key hormone groups in the endocrine system/
- thyroid hormones
- growth hormones
- adrenal cortex hormones
- reproductive hormones - sex steroids, gonadotropins
Importance of thyroid hormones?
- growth
- metabolism
- development
- cardiovascular
Importance of growth hormones 2
- stimulates growth and cell reproduction
- protein synthesis
Importance of adrenal hormones (cortex and medulla)
Adrenal cortex
- aldosterone - electrolytes
- cortisol - stress
- androgens - reproduction
Medulla
- sympathetic nervous system control
- EPI and NEPI - fight / flight
