Musings, politics and environmental issues

Archive for April, 2019

Radioactive caesium in Danish district heating residues linked to Chernobyl

Repercussions are still being felt from the Chernobyl nuclear accident in 1986 in Ukraine, which at that point was still the USSR. See here for information in Danish.

Last year, radioactive caesium-137 was detected in ash from wood chips used in Danish district heating biomass plants. The wood chips were sourced from the Baltic countries, and the radioactivity is believed to have resulted from the nuclear accident. The burning process concentrates the radioactive material in the ash, which “might mean” that the ash must be treated as radioactive material according to Danish radiation protection law.

One of the district heating plants that use wood chips from the Baltics is Halsnæs Forsyning. There, about 30,000 tonnes of wood chips are handled annually, which results in approximately 800 tonnes of ash.

An Executive Order of the Danish Health Authority states that there are clear rules for how bio-ash should be handled and who is responsible. The individual district heating plant is obliged to know the ash content of radioactive substances.

The district heating organization District Heating DK have been researching the situation. Last year, a report that looked at 10 utilities showed that the radioactivity is so small that is is not likely to pose a health problem to workers or anyone else (!) but District Heating DK are doing another study that is designed to clarify the processes involved.



Call for Health Impact Assessment for Helguvik silicon smelter

I got a document yesterday from the Planning Agency (now available in Icelandic on the Net) because I’d made comments to a proposal for what should be covered in an environmental impact assessment concerning improvements to the closed-down silicon smelter formerly owned by United Silicon.

Besides allowing comments from the public (which they took no notice of, except to say that many residents had complained of health problems!), they’d asked for comments from bodies such as the Environment Agency, Directorate of Health, the local council, the Marine Research Institute, the Met Office and others.

Some of the information was particularly interesting. For instance, the Directorate of Health said that a Health Impact Assessment should be done because of all the complaints received from local residents. Stakksberg (the current owners) responded by saying that they were not aware of HIAs being done in Iceland, and until legislation was passed about HIAs, they were not going to do one!

When United Silicon was operating the plant, the temperature of the cooling water was 7°C and was discharged into the sea afterwards, when the temperature was not supposed to go over 10°C. Was this the case? No – the maximum recorded cooling temperature of the cooling water was 36°C! As a biologist, I was appalled by this. The draft EIA has to show how much area will be affected by the cooling water and what the temperature difference will be.

The Met Office were concerned about the aquifiers, which they said were very susceptible to disturbance in that area. They also said that there should be a scenario for when the worst possible weather conditions occur, i.e. calm weather/gentle breeze and also when there was high humidity.

They also had concerns about some of the substances emitted from the operation, some of which are bio-accumulative (or accumulate in soils) or do not change into less toxic materials. These substances include heavy metals such as arsenic, persistent organic compounds and sulphur compounds.

The Environment Agency said that because most of the odour problems occur when the smelter is not running at full capacity, a distribution model of pollutants should be done for volatile organic compounds (VOC) with different exhaust temperatures.

The EA also said that the option of not starting up the plant again should be considered.

Many other points came up too, and there were conflicting opinions from different agencies about whether a emergency chimney was needed or not.

I still suspect that the plant won’t start up again. Stakksberg announced long ago that they were trying to sell the plant, but they haven’t succeeded yet. They originally implied that they had no intention of running the plant themselves.

The document I received yesterday raised so many issues that I suspect it will take a long time to process them all.