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Red Sludge: Danube Pollution Easing?

  • October 9th, 2010
  • Posted by EUEditor

hungary-mud_4-edienet.jpgHungarian authorities say that discharge of toxic sludge from the burst tailings dam mat Ajka has been dissolving in the Danube River to levels not harmful to aquatic life.


High levels of pollution were recorded in sections of the great river at first, at 14 on the pH scale, a measure of alkalinity, but then came back down to 9 or 8, considered sustainable.

Fish kills being observed in the water have reportedly stopped.

hungary-mud-_2-worldbullrtinnet.jpgEmergency services began a large-scale clean-up operation when the waste from aluminium processing began coursing through villages in South-west Hungary on Monday(see EUAustralia Online, Hungary Toxic Sludge …, 7.10.10).

They have been digging holding weirs in watercourses to slow down the flow, and spraying industrial chemicals to dilute the sludge, and neutralise elements in it, to reduce the pH content.

Those efforts could not save the Marcal River, the main channel flowing north into the Danube, with stretches of the stream pronounced dead.

The Greenpeace organisation disputes the positive environmental reading, saying it’s obtained independent laboratory tests which show high levels of arsenic getting into the river.

Zsolt Szegfalvi of Greenpeace Hungary said in Budapest  (8.10.10) the arsenic levels were 25 times higher than the officially permitted level in drinking water, and significant mercury and chrome deposits had also been measured.

A fifth person has died from injuries received when the caustic flood swept across 40 square kilometers of country; an additional  120 were hurt.


water-pollution-genvnet.jpgThe pH measure is a well-recognised tool for assessing levels of acid or alkalines in water, related to life-support.

This explanation is published the Wheeling Jesuit University in America:

The pH of a liquid is the negative logarithm of the concentration of hydrogen ions (catinos) in the solution.

pH = – log [H+]

Because the pH scale is logarithmic, every single unit change in pH actually represents a ten fold change in the number of hydrogen ions in a solution…

The pH values of natural surface waters usually range from 5.5 to 8.5. Extremely high (9.6) or low (4.5) values are unsuitable for most aquatic organisms. Young fish and immature stages of aquatic insects are extremely sensitive to pH levels below 5. Click on image at left for more.

Changes in pH can also affect aquatic life indirectly by altering other aspects of water chemistry. Low pH levels accelerate the release of heavy metals from sediments on the stream bottom. The heavy metals can reduce the chance of survival of most aquatic organisms.

From Matt Allbritton, on eHow:

One of the most devastating side effects of pollution is increased acidity in rain and groundwater. This affects animals and plants, and has long-term implications for our environment.

The pH Scale
1.    The pH scale measures the acidity or alkalinity of a liquid, from 0 to 14—7 is neutral, anything below 7 is acidic and anything higher is alkaline.
Natural Water
2. Rain and groundwater tend to be naturally slightly acidic, usually no lower than 6 on the pH scale. Most plants and animals tolerate this level of acidity without any problems.
3. Byproducts of air and water pollution are acidic. While natural alkaline substances in the soil can reduce their impact, the result of such pollution is often a much more acidic environment than normal.


Matt Allbritton,  “Water pH & Pollution”,, Bellevue, WA, USA, 9.1.10., (9.10.10).

Montreal Gazette, Quebec/ AFP, “Water life in Hungary’s Marcal River is dead: official”, 7.10.10., (9.10.10).

Wall Street Journal, NY / Dow Jones, Budapest, “Hungary Toxic Mud More Dangerous Than Thought-Greenpeace
“, 8.10.10., (9.10.10).

Wheeling Jesuit University, MD, USA. “Exploring the Environment: Water Quality – Acid Mine Damage”, (Image data courtesy Dr. Ben Stout)., (9.10.10).