Chlorinated Compounds & Heavy Metals Flashcards
Chlorine and chlor-alkali processes
Chlor-alkali process: Cl2 produced at graphite anode and Na amalgam produced at Hg cathode
POPs
Persistent Organic Compounds names in the Stockholm Convention of 2001 for protecting human/environmental health from chemicals that remain in the environment for a long time, are widely distributed, and bioaccumulate in fats (identified 12 “key” POPs like DDt as well as PCBs)
Classes of pesticides
Generation 0: shoes, flyswatter, etc.
Generation 1: inorganics
Generation 2a: chlorinated compounds like DDT
Generation 2b: organophosphates
Generation 3: hormone mimics, pheromones, growth regulators
Problems with PCBs and their toxicity
Used as dialectric fluids in transformers and are non-flammable, good insulators, long life, non-corrosive, non-toxic, but…
1) Persistent and bioaccumulate
2) Half life of 5 years
3) Biomagnify
4) Magnified 10^7x
Toxicity:
1) Very high potential exposure because they are everywhere
2) Acute exposure: chloracne
3) Chronic exposure: joint ache, headache, fatigue
4) Suspected hormonal activity
Environmental Contamination Act 1980
WRT PCBs act stated that no new PCBs can be produced, PCBs in use can remain so until 2020, and put onus on the companies using PCBs to take care of them
Toxic metal chemical pollutants: Mercury
Liquid at room temp, rare element in earth’s crust, HgS (cinnabar) is the most common found in active regions where dense rock is forced to the surface.
Atmospheric mercury is acutely toxic, causing cough/breathing/stomach problems/psychotic reactions, and chronically toxic, causing fine tremors escalating to violet muscle spasms/vivd dreams/depression
Current uses include batteries and eye drops, discontinued uses include medicine and paint
Organic mercury occurs in sediments = methylmercury, and can be inhaled or absorbed through skin
Toxic metal chemical pollutants: Lead
A neurotoxin that accumulates in soft tissue/bone and causes neurological effects.
1) Roasting: 2PbS + ∆ to 2PbO + SO2
2) Reduction: 2PbO + C to 2Pb + CO2
Current uses include batteries, pipes, paint, discontinued uses include food cans, pesticides, birth control
Bioaccumulation: t1/2 fats = 6 years, t1/2 bone = 20 years
Needleman study was conducted in inner city Boston looked at the Pb poverty cycle where children in inner city were exposed to more Pb = learning difficulties = lower wages = poverty cycle and the results of this study influenced the early ban of tetraethyl lead
Lead poisoning: symptoms include sleeplessness/irritability/lack of judgement/effects on brain/abdominal pain/anemia/brain swelling/death
Known to cause issues in developing tissues in children’s developing brains after being passed in the womb (Flint Michigan 2016 insane political battle = water shut off so the city went back to using old water system and people were poisoned from lead in pipes)
PCB disposal
1) Burning = toxic compounds
2) React with Na = $$ and a useless waste product
3) React with H2 via electrolysis of water = $$$$, but useful byproducts
4) React with KOH = 1 biodegradable product, 1 extremely dangers $ to store product
