The red sludge tragedy in the Danube Basin
The red sludge tragedy in the Danube Basin
The focus of the world has been on the Danube River Basin as pictures of injured people, damaged houses and dying wildlife around Kolontar, Hungary, were circulated two months ago. But the images also show the basin working together to clean up the area and to understand how to avoid such tragedies in the future.
This break on 4 October caused the disaster. For some days it was even feared that the northern wall of the reservoir might collapse. Measures, such as building dykes, were taken to divert the flow of another possible sludge wave, providing 22,000 tons of gypsum and necessary acetic acid supply as well as pumping red sludge out of Reservoir 10 into Reservoir 11. This danger has so far been averted.
Just after noon on 4 October, a dam broke at MAL Ltd., the Hungarian Aluminium production and trade company situated around 150 kilometres south-west of Budapest. As a consequence, about 700,000 m³ of red sludge spilled out of the facility’s Number 10 Reservoir and entered the Torna Creek and Valley, thus reaching the Marcal River. Ten people died in the high-alkaline sludge and about 120 were injured. Five tons of rocks from the broken dam have been pushed by the flow more than one kilometre away from the reservoir. The red flood wave was up to 2.5metre,s high and hit parts of the village of Kolontar one kilometre away (heavily damaging 35 houses), reached Devecser seven kilometres away (damaging 207 houses), finally hitting 14 houses in Somlovasarhely. In total, an area of about 1100 hectareswas affected: mainly crop land (600 hectares) and meadows (400 hectares), Natura 2000 sites or sites designed for nature protection (90 hectares) and forests (50 hectares).
Apart from the immediate effects of the wave of red sludge, there was also concern for a possible contamination of Hungary’s waterways and air, and concern that the major environmental pollution might reach the Danube River. “The ICPDR was very much concerned about the possible pollution of the Danube River,” explains Philip Weller, its Executive Secretary, “The Danube not only links several countries in Central and Eastern Europe, but is also the drinking water resource for millions of people.”
The red sludge is collected in containers or plastic sheets and treated as hazardous waste. During this work goggles and a mask must be worn to prevent contact with the eyes or the airways. For most areas neutralisation, cleaning up the sludge and ploughing in the residue may be sufficient, according to Hungarian officials.
Mitigation efforts. Immediate emergency response
measures were undertaken for the protection of the
population and the environment. By 4pm on 4 October,
the highest alert level was ordered by the Environmental
and Water Directorates and the Headquarters
of HUWater-caused Damages seated in VKKI (Central
Directorate for Water and Environment), Budapest.
“The Hungarian Authorities have undertaken all measures to avoid further pollution of water, soil and air; we have tried to keep the pollution within the Marcal River catchment and to decontaminate this affected area as soon as possible to limit the harmful impacts on men and environment,” underlined Laszlo Perger, Central Directorate forWater and Environment (VKKI) Hungary, and Member of Hungarian Delegation to the ICPDR River Basin Management Expert Group.
A major problem was the sodium hydroxide content in the red sludge, which was the main danger for humans and the environment (see box: What is red sludge?). The content of sodium hydroxide in Reservoir 10 was – according to Hungarian officials – between 5% to 8%. One objective in the field of water protection was to keep the highly alkaline pollution as local as possible - hence to localise it in the Marcal River and to limit the metallic and organic contamination in the Rába, Mosoni-Duna and Danube rivers.
“An impressive sets of measures were undertaken to minimise the risk for the pollution of the waters of the Danube,” adds Weller. To that end several measures were undertaken: six underwater dykes were constructed in different sections of the Marcal River to slow down the water flow so that suspended solids could settle and to ease the neutralisation measures to improve water quality – to lower the pH level and to elutriate the pollution. The day following the accident, various neutralisation materials, such as gypsum and bio-acetic acid, were discharged into the Marcal River.
The intensive neutralisation measures were successful and the pH value of the Marcal River decreased, so no major water quality problems in the water of the Danube River or harmful effects on the health of human beings are expected. Rainy weather washed further pollutants – alkali and heavy metals – into the Torna Creek from the surrounding areas; therefore additional gypsum was poured into the river.
WhaT is red sludge?
Red-sludge is the by-product of the principal industrial means of refining bauxite in order to provide clean alumina as a raw material for the electrolysis of aluminium. In the so called Bayer process, bauxite is digested by washing with a hot solution of sodium hydroxide. This dissolves the present alumina into aluminium hydroxide, which dissolves in the hydroxide solution, while the other components of bauxite do not dissolve. The solution is clarified by filtering off the solid impurities. This mixture of solid impurities, including some of the hydroxide solution, is called red sludge. Next, the filtered hydroxide solution is cooled and the dissolved aluminium hydroxide precipitates as a white, fluffy solid; when heated again the aluminium hydroxide decomposes to alumina, which is then used for the production of aluminium. The red sludge is composed of a mixture of solid and metallic oxide-bearing impurities. Its distinctive red colour is caused by oxidised iron, which can make up 60% of the mass of the red sludge. Having been subjected to sodium hydroxide treatment, it is highly caustic, with pH values in excess of 13.2. A typical plant in Europe produces about 3 tonnes of red sludge waste per ton final aluminium.
Instant injuries are caused by direct contact with the red sludge: when alkali combines with water, such as the water in the skin, it produces heat, causing skin irritation, burn injuries and even damage to eyes on contact. The severity of the effect and the resulting injury depends on the length of the contact and the concentration of the lye. Sodium hydroxide dissolved from red sludge can destroy the flora and fauna of surface water and can even kill fish.
The alkali itself has no long-term effect on the environment, since water dilutes it and hence reduces the pH.
Spreading information to avoid the spread of pollutants. All these measures were accompanied by specific emergency water-quality monitoring undertaken by Hungary as well as in the downstream countries, to investigate the early direct impact to the Danube river (see box: The Accident Warning System of the ICPDR). “This accident has shown that the AEWS of the ICPDR works and can be used as a reliable source of information between all Danube countries,” explains Igor Liska, Technical Expert for Water Quality in the ICPDR Secretariat.
“We are relieved that major pollution beyond the local streams and rivers could be avoided,” says Maria Galambos, Member of the Hungarian Delegation to the ICPDR. “The intense monitoring of the Hungarian National Public Health Centre also revealed that the drinking water was safe at any stage of the accident.”
Decreasing risks from heavy metals. According to the Hungarian environmental agencies, the content of heavy metals in the red sludge posed a relatively low acute toxic risk as their concentrations were rather low. However, the release of heavy metals could have a longterm implication on the environment as they damage the nervous system in animals and humans and build up in the food chain. The radioactivity of the red sludge was insignificant, according to Hungarian authorities, and therefore not harmful to humans and the environment. The exact assessment of those possible impacts in the future must be preceded by a thorough monitoring of the heavy metal content in water, suspended particulates and bottom sediments in the Marcal, Rába, Mosoni-Danube and Danube rivers.
Monitoring results identified an increased concentrations
of some heavy metals – mainly mercury and
aluminium. In the Slovak reach of the Danube downstream
the mouth of the Mosoni-Danube, the elevated
concentrations of aluminium, vanadium and arsenic were observed on 7 October with a sharply decreasing
tendency. According to the monitoring results of the
countries further downstream the Danube the threshold
values for the measured substances, including several
heavy metals, were not exceeded according to specific
regulations of the European Union.
Currently the costs for cleaning, decontamination and compensation on a national level are estimated between 100 and 200 million US Dollars. International and national funds have been established to provide some compensation for private persons for their losses and damages.
The dilution of heavy metals downstream resulted in a further decrease of their concentrations, so that the director of CroatianWaters Zoran Djurkovic said on 10 October that the quantity of metals measured in the Danube River “does not exceed the maximum limits allowed for even drinking water”. On the Romanian Danube section at Bazias (km 1071), the concentrations of mercury and aluminium have been reported below the limit values. However, in order to have a clear picture on the threat stemming from the heavy metals to the environment and human life, more detailed information is continuously assessed.
One problem that has still not been solved is that dried red sludge is a very fine powder, which irritates the respiratory passages when inhaled. Its alkalinity causes stronger irritation than normal dusts may cause.
International assistance. Disaster relief efforts on agricultural land are also ongoing. According to measurements by the Research Institute for Soil Science and Agricultural Chemistry of the Hungarian Academy of Sciences, the contamination did not permeate the soil at a depth in excess of 10 cm and the quantity of heavy metals in this layer also did not exceed the contamination threshold.
Hungary asked for EU assistance in the frame of the EU European Civil Protection Mechanism. On 11 October, a team consisting of five experts with relevant international experience from Belgium, Germany, Sweden, France and Austria joined the Hungarian team to provide assistance in eliminating environmental damage.
Working together under the ICPDR. “There is no question that such accidents need to be avoided,” states Mihaela Popovici, Technical Expert for Pollution Control at the ICPDR Secretariat. “A special ICPDR Accident Prevention Task Group is working on how this can be best done.”
The most important activity has been maintenance of an inventory of potential accident risk spots. Countries are encouraged to monitor these spots continuously and to undertake preventive measures to avoid accidents on these installations. In addition, an inventory on contaminated sites in areas that are in danger of being flooded is regularly updated. For these sites a special catalogue of measures has been developed. “But this is not all,” continues Popovici, “Currently we are working on a proposal on mutual assistance in the event of such an accident as well as on a proposal for contingency planning.” As the main follow-up on the accident, the ICPDR plans to review all listed accident risk spots and to evaluate whether enough measures have been taken to prevent such accidents in future.
The accidenT early Warning sysTem oF The icPdr
The Danube Accident Emergency Warning System (AEWS) is an internetbased messaging tool for international coordination set up by the ICPDR in 1996. In the event of an accident on surface waters with a possible transboundary impact, the relevant information is shared between national alert centres: the respective national alert centre submits a message by filling in a form for the specific situation. All relevant national alert centres – primarily those located downstream of the accident site – are then instantly notified by SMS and e-mail and can view the full message on the web. The system can also be used for further communication on the accident.
The tragic case of the Ajka alumina plant accident has shown how important is the proper operation of the AEWS. After being informed by Hungary over the AEWS, on the morning of 5 October, most downstream countries (Slovakia, Croatia, Serbia, Romania and Bulgaria) started an extensive monitoring of the Danube River, especially at locations where the Danube entered the respective country. Over 60 messages about the status of the Danube have been shared through the AEWS.
This system was used not only for the warning of other countries, but also for daily updates of the monitoring results of the various water management authorities of the water along the entire stretch of the Danube.
Costs and responsibilities. The MAL Ltd, which is owned 100% by the Hungarian Investors Zoltan and Arpad Bakonyi, claimed that a natural disaster led to the accident. But Hungarian Prime Minister Viktor Orban stated that the cause of the spill was presumably a human error. The Hungarian Government initiated a criminal procedure against persons unknown with “criminal negligence leading to a public catastrophe”. The Hungarian Government took control of MAL Ltd on 11 October, and the question of responsibility has not yet been solved.
As is the common practice after such accidents, questions arose of liability and who might finally pay for the damage. Currently the costs for cleaning, decontamination and compensation on a national level are estimated between 100 and 200 million US Dollars.
The red flood wave was up to 2.5 meters high and hit parts of the village of Kolontar 1 kilometre away (heavily damaging 35 houses), reached Devecser 7 kilometres away (damaging 207 houses), finally hitting 14 houses in Somlovasarhely.
International and national funds have been established to provide some compensation for private persons for their losses and damages. There are several legal instruments which could be of importance for questions of liability: the EU Environmental Liability Directive as well as the related EU Integrated Pollution Prevention and Control Directive, establishing a framework for environmental liability based on the ‘polluter pays’ principle, with a view to preventing and remedying environmental damage. Another international instrument which could be applicable – if a transboundary effect is proven – would be the Protocol on Civil Liability and Compensation for Damage Caused by the Transboundary Effects of Industrial Accidents on Transboundary Waters of the UNECE Convention on TransboundaryWaters and the UNECE Convention on Industrial Accidents.When in force - which is not yet the case - the Protocol will give individuals affected by the transboundary impact of industrial accidents on international watercourses (e.g. fishermen or operators of downstream waterworks) a legal claim for adequate and prompt compensation.
A tragedy such as happened in Hungary could also be seen as a wake-up call for even more caution with risk sites and being prepared for the unforeseeable. “We need to undertake all measures to avoid accidents with such tragic consequences for humans and nature,” concludes Weller, “but nevertheless, we all need to be prepared for them – on the local, national and international levels.”
For more information, please visit: www.redsludge.bm.hu.
