'Australian Bush' toxins on wild side
By SIMON BEVILACQUA
September 19, 2004
HIGH levels of toxic man-made chemicals have been detected in
Tasmanian wildlife.
Organochlorides, including the banned
pesticide DDT, have been recorded in platypuses statewide.
The poisons are believed to have entered the Tasmanian eco-system
from transformer oil used in hydro power operations, farm use and
factories including pigment, pulp and paper mills.
The toxic chemicals are known to hinder immune systems and
disrupt sexual development in some species.
Organochlorides were found in platypuses from Cressy in northern
Tasmania to King Island, off the state's North-West Coast, to Lake
Pedder in the Southwest National Park.
The levels found were as high or higher than ever before detected
in Australian wildlife -- but not as high as recorded in some
European and American species.
But the shock Tasmanian findings, published in a PhD thesis in
2001, have been left to gather dust. No further research has been
conducted since.
Scientists, including the researcher who conducted the study, say
it is vital the matter be investigated.
Researcher Niall Stewart discovered high levels of
polychlorinated biphenyls (PCBs), DDT and the pesticide Lindane
while probing a fungal disease which is ravaging the state's
platypus populations.
"Although Tasmania prides itself on having a clean and green
image, the presence of moderately high levels of PCBs in Lake
Pedder, a large lake in a wilderness area, suggests the image is
based primarily on ignorance," Dr Stewart said in the study.
"The presence of some animals with very high levels, especially
PCBs, is of concern.
"Further work is needed to determine whether levels represent a
risk to platypus populations."
The pesticide DDT was used throughout Tasmania until banned in
1987.
Lindane, a farm insecticide, is still widely used.
PCBs are found in plastics, paints and coolants.
Organochlorides can cause brain damage and intellectual
impairment in children exposed to high levels.
Children exposed to low but persistent levels of PCBs
consistently score lower than non-exposed children on some
psychological tests.
The chemicals have been found to suppress the immune systems in
bottlenose dolphins off Florida which had high levels of PCBs and
DDT.
It is likely PCBs hinder immune systems by altering hormone
levels.
Testosterone levels can change with exposure to PCBs.
DDT has an oestrogen-like effect which can result in skewed sex
ratios in birds, because of testicular feminisation and reduced
hatch rates.
Lindane has been shown to disrupt the immune system in rats and
mice.
Suppressed immune systems can lead to susceptibility to viral
infections and reproductive disorders.
The thyroid glands are especially sensitive to some PCBs.
Adrenal glands are also affected.
Seals in the Baltic Sea and Beluga whales have been shown to have
adrenal problems linked to high levels of PCBs.
The Sunday Tasmanian
Copyright 2004 News Limited |
