Aral Sea (C Asia) catastrophe recorded in DNA

[Guest guest]

Aral catastrophe recorded in DNA

 

By David Shukman

BBC science correspondent in Muynak, Uzbekistan

http://news.bbc.co.uk/2/hi/science/nature/3846843.stm

 

 

Saparbey Kazahbaev understands all too well what has happened

Fresh fears have been raised about the health of populations living near

the shrinking Aral Sea in central Asia.

A new study has now found high levels of DNA damage that could explain the

region's abnormally high cancer rates.

 

This comes as the latest estimates say the Aral Sea is receding so rapidly

it could vanish within the next 15 years.

 

Once the world's fourth largest inland body of water, the sea has been

drained by a poorly managed irrigation system that supplies water to cotton

crops.

 

Toxic mix

 

If ever there was an example of manmade ecological and human catastrophe,

the Aral Sea and the dusty, salt-encrusted lands around it must be the most

vivid anywhere on the planet.

 

DECLINE OF THE ARAL SEA

Satellite images show how the inland water body has retreated

 

 

In pictures

 

In fact, it is no longer true to talk of the sea as a single entity. In the

late 1980s, its level fell so low that the centuries-old body of water

divided into two.

 

In the last eight years, the sea has fallen another 5m (16ft) and soon you

can expect official confirmation that the larger of its two parts has been

divided again.

 

What is left when these seas retreat is a vision of environmental

apocalypse: vast stretches of desert, laden with heavy doses of salt and

burdened with a toxic mix of chemical residues washed down over the decades

from the farms upstream.

 

 

Gone are the cooling breezes that once made the town of Muynak attractive.

 

This fishing port used to boast busy docks and the largest fish processing

plant in the Soviet Union.

 

Now the sea is only reached after a long day's driving over harsh terrain.

The jobs have disappeared and even the cleanest water is dangerously salty.

 

Cancer rates

 

Dust blows everywhere and carries with it toxins that enter the food chain.

 

CONSEQUENCES OF SHRINKAGE

Aral has moved 100-150km away from the original shore

Fishery - 44,000 tonnes per year - has totally collapsed

42,000 sq km of new salty desert emerged since 1966

Diseases - cholera, typhus, gastritis, blood cancer

Highest child mortality rate in the former USSR

The impact on public health is devastating. Malnutrition is rife as are

conditions including anaemia and TB.

 

Most alarming is a rate of a particular form of cancer - cancer of the

oesophagus - that is the highest in the world.

 

Up to 80% of cancer victims in the region suffer this form of cancer.

 

For years the likely cause has been suspected to be the intensive use of

pesticides and herbicides on the vast cotton fields to the south of the Aral

Sea. Now new research appears to provide support for that.

 

Dr Spencer Wells, of the National Geographic Society and formerly Oxford

University's Wellcome Trust Centre for Human Genetics, studied DNA samples

taken from the local population and found widespread genetic damage.

 

The study focused on the level of a marker known as 8-OHdG and showed rates

of damage 3.5 times higher than seen in samples from the US.

 

In the wind

 

In farm workers, those closest to the agricultural chemicals, the rate

increased to 5 times.

 

According to Dr Wells, the implications of this could be long lasting.

 

" This means not only that people are more likely to get cancer but also that

their children and grandchildren are too, " he told BBC News Online.

 

 

The water has been taken to feed the " white gold " - cotton

What is not proven is whether the genetic mutations found in the adults are

indeed passed on to later generations. That will take further study.

 

In the meantime, the cancer wards in the main hospital in the provincial

capital Nukus are overburdened.

 

One patient is 61-year-old Saparbey Kazahbaev, a biologist who has spent the

last 30 years living beside the Aral Sea and studying the effects of its

decline.

 

He is now recovering from surgery to remove a tumour from his oesophagus.

 

Too weak to raise himself from his bed, he explained in a rasping voice how

the poisonous salts in the air have a double effect on humans.

 

First they enter the respiratory system; second they enter the food chain

through plants and animals that are eaten.

 

'No alternative'

 

The government of Uzbekistan denies it has a major healthcare problem on its

hands.

 

The worst affected region falls in the province of Karakalpakstan and the

region's deputy health minister, Atajan Hamraev, admitted there were

problems but said they were under control.

 

 

Rusting boats are grounded kilometres from the sea

We asked him whether it was wise to continue growing cotton, given the way

it soaks up all the water that used to flow into the Aral Sea and the new

evidence of health risks from the chemicals sprayed on the crops.

 

His response was defiant: cotton is Uzbekistan's biggest export earner.

 

Mr Hamraev said that stopping the growing of cotton would make public health

worse and leave stomachs empty. " There's no alternative, " he said.

 

So the cotton fields are busy, the sea shrinks and the hospitals struggle to

cope.

 

 

 

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