Harmful chemicals in green Glasgow burn to be flushed

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Polmadie Burn
Image caption,
The water has turned bright green at Polmadie Burn

High levels of a toxic chemical which turned a Glasgow burn bright green are to be flushed into the River Clyde, the city council has said.

The burn in Polmadie was fenced off after inspectors from environment watchdog Sepa discovered a concentration of hexavalent chromium.

The element, which has been linked with cancer, is largely banned in manufacturing in the EU.

Glasgow City Council said a proposal to flush out the burn had been agreed on.

A spokeswoman said: "Following a site visit last week and confirmation about the temporary high concentration of hexavalent chromium in the Polmadie Burn, Heras fencing has been put in place to restrict public access and there is an agreed proposal to temporarily increase the flow of the burn, in a controlled way, to dilute the level of chromium."

Image caption,
High levels of hexavalent chromium were found in the water by SEPA

Environmental officers warned the contamination posed a risk to public health.

The source of the chemical in the burn, according to Sepa (the Scottish Environment Protection Agency), was from historical chemical works which existed in the area from the 1800s until the late 1960s.

Much of the waste by-products were used to backfill the former clay pits, near the West Burn in Shawfield.

Image source, Getty Images
Image caption,
Water will eventually flow into the River Clyde following a flushing process

The council said chemicals contaminated the West Burn before seeping into the Polmadie Burn.

To tackle the link, the West Burn was diverted into the River Clyde on 21 January and is in the process of being sealed up, according to council officials.

Meanwhile temporary fencing was erected to restrict public access to the Polmadie Burn.

What is hexavalent chromium?

Hexavelent chromium is a heavy metal with a number of uses across industries including textile dyes, paints and plastics.

While metallic chromium is inert and safe, in certain chemical compounds chromium forms ions with a plus-six positive charge. If this hexavalent form of chromium then gets into the body - eaten, or dissolved in water, or vaporised by a welding torch and then inhaled - it can cause cancer.

It was restricted from use in electronics manufacturing in EU countries in 2003 under the Restriction of Hazardous Substances Directive.

It was listed alongside nine other elements including lead and mercury.

In the early 90s, US legal clerk Erin Brockovich brought a successful case against the Pacific Gas and Electric Company for allowing the substance to contaminate drinking water in Hinkley, California.

Flushing process

It is thought the majority of chromium that was getting into the Polmadie Burn has now stopped. However small volumes could continue to seep in until the West Burn is fully sealed.

Sepa expects the green colour will gradually disappear which will be helped by heavy rainfall.

A proposal to allow more water to flow into the Polmadie Burn to dilute the chemicals was agreed on Tuesday following a meeting between Glasgow City Council, Sepa and Clyde Gateway.

A spokeswoman from Sepa said pollution was the result of chromium ore processing residue from a former chemical works, previously located in the Shawfield area.

She said work to stop contaminated ground water from entering the Polmadie Burn was due to be completed in the next couple of weeks.

The flushing process requires a licence from Sepa and must be done in a controlled manner.

The water will eventually flow into the River Clyde.

It is expected to take place in the next two weeks.