By John
Mikkelsen – Saturday 19th January, 2012
IGNORANCE
is said to be bliss, but medical and science experts have pointed out it
could have serious consequences when it comes to contaminated seafood,
including oysters.
Gladstone
residents and tourists remain largely unaware of dangers from potentially
contaminated oysters and shellfish following toxic algae blooms and the
presence of heavy metals detected last year. However, in NSW
authorities were quick to issue an official warning about contaminated Sydney
oysters in the lead up to the Christmas holidays..
Toxic
lyngbya majuscula algae was positively identified in Gladstone Harbour
last year following the hospitalisation of two Turkey Beach fishers, and
poisonous diatoms, another form of marine algae, were also detected, but no
health warnings were issued.
The risks
of consuming possibly contaminated local shellfish including oysters were
recently highlighted by aquatic disease specialist Dr Matt Landos following
extensive research in Gladstone waters.
Dr
Landos told the Queensland Telegraph that shellfish
populations exposed to the increased sediment load generated by dredging were
likely to have been significantly impacted.
“The
timing of mortality of oysters (and other aquatic biota) suggests that sediment
re-suspension and associated increased metal exposures from the dredging and disposal
project has contributed to oyster mortalities.
“Rio
Tinto hired a private ecotoxicology firm to undertake
oyster testing in Gladstone harbour in 2012, but the results which were very
clearly not good for the oysters remained suppressed,” Dr Landos
claimed.
He
explained that oysters are routinely used to assess toxicity of water and as
“sentinels for accumulation of metals”.
While
Queensland health authorities have failed to act, their NSW
counterparts issued an immediate health alert following the discovery of
contaminated oysters in Botany Bay after the
toxic algae outbreak there.
They
warned against eating oysters, clam, crabs and abalone, and an environmental
medicine specialist, Dr Andrew Jeremijenko, believes similar warnings should
have been issued previously at Gladstone.
Dr
Jeremijenko has also called for the monitoring of oysters
in Gladstone waters following the continuing controversy over the health of
local seafood and other marine animals.
Dredging
has been blamed as the most likely cause of the fish disease by Dr Landos,
but this has been denied by Gladstone Ports Corporation and Fisheries
Queensland which both blame the floods two years ago.
Dr
Jeremijenko also believes the dredging and the
disturbance of toxic compounds in the silt is responsible, and he has also
warned that extreme cases of toxic algae poisoning could result in human
fatality.
He told
The Telegraph yesterday that monitoring should be conducted for dangerous
algae, including the type which produces paralytic shellfish poisoning (PSP)
as found in Botany Bay.
“There
should be a program of monitoring the Gladstone oysters for toxins such as
heavy metals and PSP toxins, but currently this is either
not being done or the data is not being made public.
“ In Gladstone
Harbour, despite far greater environmental pollution and
industrial activity than Botany Bay, there
are no warnings about the oysters and whether they are safe to eat.
“What we
now know is that an independent scientist has found them to be affected.
“
Gladstone harbour has had multiple toxic algal blooms associated with high
turbidity and high nutrient levels, but the algae associated with these blooms
has not always been identified.
“PSP
can be fatal in extreme cases and children are more susceptible.
“Despite
destruction of oyster habitat, diseased oyster shells and collapse of stock,
the State’s willingness to monitor and protect the oysters in the harbour, and
the people that eat them, is lacking”.
Dr
Jeremijenko said another study in Gladstone Harbour
a decade ago during a previous dredging program had also found that oysters
were taking up toxins such as heavy metals, arsenic and aluminium and “the
closer to the dredging, the worse it was”.
“The
authorities should be lobbied now to take appropriate measurements and do this
as part of the UNESCO- recommended Gladstone Enquiry,”
he said.
