Iceland review - 2015, Blaðsíða 69

ICELAND REVIEW 67
ICELAND REVIEW 67
polluted cities in Europe have pH 4.0
[pH 7.0 is neutral but most rain is mildly
acid because of carbon dioxide in the air],”
explains Sigurður. SO2 emissions by large-
scale industry used to be a major problem
in Europe, causing acid rain, which fur-
thers rock dissolution and, hence, release
of aluminum. “Aluminum is the third most
common element in the Earth’s crust. It’s
poisonous when it dissolves in water, but it
doesn’t dissolve easily—except at very low
pH.” When carried into lakes and rivers
it precipitates in the gills of fish, suffocat-
ing them. “The aluminum concentration
in the snow close to Holuhraun was high
enough to kill salmon fry,” states Sigurður.
Sulfuric acid also causes erosion of human
infrastructure, and if it ends up in ground
water, it’s harmful for human health, he
adds. Today, China and India are the world’s
biggest emitters of SO2.
NATURE’S DEFENSES
In addition to dust storms neutralizing
sulfuric acid, other conditions around the
Holuhraun eruption were fortunate too,
Sigurður explains. “The SO2 also needs
sunlight to oxidize to sulfuric acid particles
in dry air. When the eruption started in late
August, we were entering the darkest period
of the year. Plus, the violent autumn storms
tore the SO2 cloud apart and blew it off the
island and out to sea, northwards, towards
more darkness,” he reassures. “We were
lucky in how exceptionally bad the weather
was.” With one depression following the
other, wind velocity was well above average
last autumn.
“Now compare this to Skaftáreldar, an
eruption where everything was ten times
bigger,” says Sigurður. The fact that
Holuhraun is the largest eruption Iceland
has seen since then shows the massive scale
of Skaftáreldar. “It started in early June,
when the brightest time of year was about
to begin with 24 hours of daylight and calm
weather,” he elaborates, pointing out that
livestock had just been released to pasture.
“The timing was terrible, coupled with
people’s inability to deal with the effects.
The calm conditions caused the pollution
to circulate over the country. In the case
of Holuhraun, many farmers had already
rounded-up their sheep because of warn-
ings, and wild geese had left the area.”
But the scientists weren’t prepared to
relax just yet; extensive amounts of soluble
aluminum salts were trapped in the snow.
“The fluctuating weather helped, which
washed them away little by little, but we
were concerned about the snow higher up
and what would happen at spring thaw,”
says Sigurður, explaining that 50-80 per-
cent of pollutants in snow are released with
the first 30 percent of the meltwater. So
he, two colleagues from the University of
Iceland and a member of search and rescue
association ICE-SAR ventured on a journey
across Vatnajökull glacier to take samples in
different locations. It turned out that even
though the snow was polluted, an unusually
high amount had precipitated. As spring
arrived, osmotic samplers in rivers showed
no signs of serious acidity levels or alumi-
num concentration. Dilution by unpolluted
snow and interactions with dust and rock
did the job, Sigurður states.
FUTURE CONCERNS
In their article in Geochemical Perspectives
Letters, Sigurður and his colleagues con-
clude that the timing and location of the
Holuhraun eruption in the remote high-
lands caused the impact on people and the
environment to be minimal. Yet, “There
is bound to have been an environmen-
tal impact considering that the Holuhraun
eruption emitted more SO2 than all of
Europe in one year,” stresses Sigurður. The
future consequences of the pollution remain
to be discovered, he says, adding that the
long-term effects on humans, animals, grass,
hay and soil have yet to be evaluated by
biologists.
In that context, Sigurður mentions the
mysterious death of sheep which occurred
in the 2015 lambing season in all parts of the
country—although South and Southwest
Iceland were the areas worst affected. A link
hasn’t been established, but the eruption in
Holuhraun has been named as a possible
cause. Veterinarians are still investigating
the incident.
Meanwhile, the consequences of repeated
exposure to high levels of SO2
on human
health are being studied by the University
of Iceland’s Institute for Sustainability
Studies. “The article is the first of many,”
says Sigurður. “All the scientists involved
are now working on in-depth research in
their specific fields.” And with signs of
magma accumulating under Bárðarbunga
again, reported in September, the volcano is
making sure to keep them on their toes. *
ENVIRONMENT