Persistent organic pollutants (POPs) Flashcards
What is the main reason pollutants will build-up in the environment?
when the rate a chemical is removed is slower then the rate it is emitted
What key characteristic is shared by all POPs that makes them persistent?
Carbon-halogen bonds
What are the 3 main carbon-halogen bonds found in POPs?
Carbon-Chlorine
Carbon- Bromine
Carbon-Florine
What is the relative strength of the 3 carbon-halogen bonds in POPs? (strongest to weakest)
Florine
Chlorine
Bromine
Why do biota/enzymes find POPs hard to degrade?
they are not found readily in nature
What is UNEP Stockholm?
United Nations Environmental Programme
- Stockholm convention (1972)
Which country has not ratified UNEP?
The USA
How many chemicals are covered by UNEP?
Originally 12 (dirty dozen) - mainly organochlorine
Now 22 - Chlorine, Florine and Bromine
What does BFR stand for?
Brominated Flame Retardants
Where are BFRs used?
wide range of everyday products to give flame retardancy (efficiency debated)
What are some examples products with BFRs in?
Chairs
Phones
Plastic goods
What are PBDEs?
Polybrominated Diphenyl Ethers
Where is the main exposure area to PBDEs?
indoors- so inhalation of indoor area (air and dust)
Bioaccumulation in food
Who are most at risk of accumulating PBDEs indoors?
Young children who will crawl about collecting dust, putting hands in mouth etc…
What was happening with concentrations of BFRs and organochlorine POPs at the turn of the 21st century?
BFRs- increasing in concentration
Organochlorine- dcreasing
Where/ what was used to see the trend in POPs in the environment?
Human milk from Swedish mothers
Why was the concentration of organochlorine in human milk decreasing at the turn of the 21st century?
Due to bans on their use which had been out into place in the late 1960’s
What can happen to birds which are exposed to higher levels of organochlorines?
Will tend to have thinner egg shells
What is the problem with birds having thinner egg shells? (organochlorine)
when going to sit on the egg for incubation the egg would be crushed
What bird was studied to see the effect of organochlorine on egg shell thickness?
% gull species which had populations which both did and didn’t feed at landfill
What were the results from looking at gulls, landfill and shell thickness?
There was a statistically proven correlation that eating at landfill and being exposed to more organochlorine was thinning their egg shells
Why will younger generation have lower concentrations of PDBEs in their system?
not just being younger so less time but also because they have been phased out so not as present in products
What is the understanding around POPs and specifically organochlorine?
not fully understood
What “bold” statement did the UK government on toxicity note concern about with human health associated with organochlorines?
Neurodevelopment effects in infants
Adverse thyroid impacts
What are PFAS?
Perfluoroalkyl Substances
What makes PFAS different from other POPs?
They have a hydrophobic and hydrophilic parts
Where are PFAS widely used?
Fire-fighting foams
Stain repellent treatment (Scotchguard)
Waterproof outdoor clothing
Greaseproof food packaging
What have the media named POPs due to their strong C-F bond?
“forever-chemicals”
What are the main exposure sources for PFAS?
Indoor exposure- dust, air
Food- bioaccumulation, Grease proof packaging
Drinking water (not really known)
Who are EFSA?
European Food Safety Authority
What did EFSA just release in relation to POPs?
very strict exposure limits (show virtually everyone exposed to harmful levels)
What is the main health concern of PFAS on humans? (and other potential)
Reduce immune response of children to vaccines
Increase risk of developing kidney and testicular cancer
Raise cholesterol
What is an American example of PFAS contamination?
Incident in West Virginia where a chemical company released PFAS into the local environment
Why was the West Virginia PFAS incident made worse?
Where locals got their water was a vert local supply so PFAS remained more concentrated
What were the effects of the West Virginia PFAS spill?
Death of local cattle
70,000 people affected
What concerns have other countries had post the PFAS incident in WV?
Contamination of water supplies near military air ports where regular fire-fighting foams are used in training exercises
What has been done to reduce BFR contamination?
Banned form being added to new products in the last decade
What is the good news surrounding human milk and BFR concentratioN?
Found some containments which had been controlled had reduced while some still waiting regulation increased
What real life study is being carried out with positives and negatives related to BFRs?
As being banned will fore risk increase and is this risk worth taking over BFR health effects
