WELLINGTON, May 6 (Xinhua)
-- New Zealanders burning treated timber
to keep warm in winter have
caused airborne arsenic levels in some
of the country's towns and
cities to exceed national and
international guidelines, a government
research institute warned
Monday.
Air monitoring by the
Institute of Geological and Nuclear
Sciences (GNS Science) found that
atmospheric concentrations of arsenic, a
known carcinogen, were in some cases,
twice the upper guideline for human
health.
The studies suggested
that sufficient quantities of timber
treated with copper-chrome-arsenic were being
burnt to potentially cause acute or
chronic illness in sections of the
population.
The most likely
source of the treated timber was
off-cuts from renovations and
demolitions.
"These findings show
that air in New Zealand urban
centres is not as clean as we
would like to think," GNS Science
study leader Perry Davy said in
a statement.
"In fact some
of the winter measurements are more
like the air we expect to
encounter in polluted overseas
cities."
The disposal of
domestic fire ash that contained
residual arsenic, copper and chromium
in gardens could also contaminate
vegetables.
The highest average
concentrations of were mainly in North
Island centers, including Auckland, the
country's biggest city.
Some
municipal councils had begun enforcement
and community education programs to
stop the burning of treated wood,
but the monitoring showed more work
was needed, Davy
said.
"Particles that are 10
microns in diameter or smaller are
seen as a health hazard as they
can get past the body's
defences and cause multiple health
issues when they settle in the
lungs. Larger particles readily settle
out of the air and are less
of a threat."
（Editor：LiangJun、Yao
Chun）
