Lecture 14: Toxicology in the Artic Flashcards
______: metal chelation and solubilization (remove contaminants, particularly heavy metals, from soil or water by concentrating them in the plant’s tissues, which can then be harvested and disposed of)
phytoextraction
_____: convert volatiles to less toxic forms
phytovolatilization
_____: detoxification of organic substances
phytodegredation
_____: metal immobilization and toxicity reduction (reduce the mobility and bioavailability of contaminants in soil, primarily heavy metals, by stabilizing them in the soil or rhizosphere, preventing further dispersal)
phytostabilization
_____: root secretions degrade organic substances
phytostimulation
T/F: Cold temperatures slow down abiotic and biotic degradation processes
true!
+10°C = ~2x reaction speed
_____ regions receive less intense sunlight,
and very little UV radiation
Polar
______ are the main drivers of
photodegradation
UV wavelengths
T/F: because there’s not as much photodegredation in the Artic, Contaminants that don’t break down are free to accumulate in biota
true
T/F: Arctic species tend to have more lipids
true! need for mass for insulation from the cold
many contaminants are lipophilic!! meaning they’ll house a lot more of these compounds
what is the main difference between sun bears and polar bears?
sun bears: more lean
polar bears: more bulk
how many people inhabit the canadian arctic? 4 million square km of land!
150 000 only! super isolated region
are there roads and rail connections that connect the Arctic to the rest of canada?
no, super isolated
T/F: Most of Canada’s billion dollar remediation projects are in the Arctic
true
how is the Arctic so polluted? why do we need to have so many remediation projects in that area?
tons of mining, and people just leaving contaminants all over the place
in ______, Top USA and USSR scientists discover that the Earth is round
(or maybe long distance bombers were developed, nobody knows)
1952
Traditional attack plans required
refueling in Europe/Siberia, new bombers can fly directly across the Arctic!
because of the cold war, what did Canada and the US make in the Arctic?
Distant Early Warning Line (DEW)
what was the DEW?
63 radar stations in the Arctic Circle
460,000 tons of building materials,
160,000,000 L of fuel shipped to
Arctic
Created ports, airfields, developed
existing communities to support
operations
Operational in 1957
42 sites obsoleted in 1963 due to
development of intercontinental
missiles
Fully decommissioned by 1985
how did the DEW radar stations become an environmental catastrophe?
Unneeded equipment disposed in
the ocean
Garbage left outside to be
covered by ice
Toxic waste poured into sewers
Contaminant legacy of PCBs, metals, petroleum products
T/F: DEW line contamination is largely
limited to ~10 km radius around
each site
true
Contamination up to 20 - 80 ppm in
soils, 1000x background levels
how do the contaminants around the DEW line spread to other plants/humans around the region? if its supposed to be localized
Nutrients in sewage promotes plant growth, attracts animals that eat the plants
Hunting/trapping animals is a large part of Inuit diets (clams, beluga, seals, etc)
can measure lots of PCB presence in pregnant Inuit women
limited vegetation in the Arctic = limited ______
phytoremediation
what is phytoremediation?
plants can clean up contaminants through a variety of ways
how was the DEW line cleaned up?
Of the 42 DEW line sites in Canada:
21 were upgraded to be part of the North Warning System (and presumably tidied up!)
21 were cleaned up by the Federal government (1989 - 2014)
Heavily contaminated soil brought south
for incineration
Less contaminated waste buried in
capped landfills on site.
-“Resistant to melting permafrost”
25 years of monitoring ongoing
what is the legacy of the DEW line? how did it affect the Northern communities?
Northern/Inuit communities were traditionally hunter-gatherers. Supporting the
DEW line shifted communities to be based around a wage-dependent structure.
Industry seen as an opportunity to bring money and jobs to Northern communities.
-But also big concerns about environmental impacts
Easy(ish) access to the Arctic lead to a mining boom (1970s - present)
what are the mined Arctic resources?
diamonds
gold
zinc
lead
iron
what was the Giant mine in Yellowknife?
produced gold!
burnt arsenopyrite ore to harvest the gold, made arsenic trioxide dust
produced around 4.2$ billion of gold
company went bankrupt in 1999 and the federal gov had to take responsibility
(cost approx. 4.4$ billion to remediate the environmental impact!)
what was the general timeline of the Giant Mine?
1948: Mine began operations
-7,400 kg/day arsenic dust released into the atmosphere
1951: Child from Dene Nation eats snow, dies of arsenic poisoning
-Company paid $750 to parents (~$9,000 today)
-Scrubbers added to reduce emissions to 2,900 kg/day
1958: Arsenic dust is now bagged and buried
-234 million kg of arsenic is now stored at the mine
2014: High As reported in local lakes, government decides to do something
how many of the major remediation projects in Canada are in the Arctic?
three out of four!
Giant Mine, Yellowknife
DEW line
Faro Mine, Yukon
T/F: Yellowknife has higher permitted levels of As contamination
because of the Giant Mine! overall, the environment have higher guidelines because there’s just way more background levels of As
T/F: As2O3 is incredibly toxic - ingesting 0.1 g can be fatal!
true! why people die from the arsenic trioxide created by the Giant gold Mine
T/F: People in the region of Yellowknife have ~50x higher cancer risk than Health Canada Guidelines
true
arsenic everywhere
what are the long term effects of inorganic arsenic?
Skin thickening/discolouration
Heart disease
Cancer- causes lots of cell proliferation
what has been our current solution to cleaning up the Giant Mine?
freeze it like a hockey rink!
237,000 tonnes of As2O3 have been sealed underground in the mine as of January
Buying time by freezing the ground until a better long-term plan has been found
Monitoring arsenic levels in the community every 5 years (next test in 2027/28)
Prevent water from reaching the
chambers by freezing it
Remediation will continue until
2038
what are two other ways contaminants can make it to the Arctic?
ocean currents
atmospheric currents
Polychlorinated biphenyls
(PCBs)
● Polybrominated diphenyl
ethers (PBDEs)
● Organochlorines (OCs)
● Polycyclic Aromatic
Hydrocarbons (PAHs)
● Methyl mercury (MeHg)
● Per-and polyfluoroalkyl
substances (PFAS)
● Metals
these are all examples of _________ contaminants in the Arctic
long-range transport
why do many contaminants enter the food web in the Arctic?
they’re lipophilic
______ clams:
Long lived
Stationary
Filter feeder
Important food species in Iqaluit, Nunavut
Great way to measure long term contamination trends
Mya truncata
Dr. Boyd measured 52 PAHs in M. truncata, found 46!
Dr. Boyd uses ____ to measure contaminant impacts on animals and people
clams
are contaminants harmful to clams?
no
no effects on body condition, increased aerobic metabolism
______ is the biggest environmental cleanup in Canada yet!
Giant Mine, Yellowknife
what is the half life of inorganic arsenic in the human body
~10 hours
so we do not have a way to determine exact exposures, meaning people were exposed to much more than what we can measure
why isn’t drinking water an issue for people in Yellowknife, despite the Giant Mine
They take their water from upstream of the mine, and have arsenic treatments in their wastewater treatment
their water has similar levels to ours
why does Great Slave Lake not release a ton of arsenic to the ground despite being right next to the mine?
the permafrost has kept the arsenic fairly contained
______: live for about sixty years and filter the water in the exact same spot, they’re the main food source in Iqaluit so they make a great research species
mya truncata clams
what does glutathione do?
antioxidant against reactive oxygen species
biotransformation
what happened to glutamate/glutamine levels in the clams?
glutmate went down, glutamine went up, meaning lots of glutathione is being produced in the clams… makes sense as a stress response
is it safe to eat the clams?
yes! the PAHs found in the clams are the least toxic ones, and they don’t keep a lot of them
right between the amount of PAHs we’re exposed to when we use cooking oil vs when we roast vegetables… so its fine
PAH ratios indicate that most come from diesel emissions and fuel spills, how was this uncovered?
the highest level of PAHs were measured near Iqaluit, instead of further away in the ocean… coming from lots of human activity
T/F: All of these examples are being made worse by climate change
true
The Arctic is warming 4x faster than
the global average
Increased human activity (shipping,
tourism, population growth)
what happens to the contaminants?
more being introduced by increased human activity
Frozen contaminants being re-
released
other than an increase in contaminants, what other issue from climate change is putting lots of stress on life in the North?
Invasive species moving in
Multistressor effects: can species
handle toxic stress and heat stress?
