Cyanide found in soil at Helsinki power plant
Residential area planned on land found to be seriously contaminated
Exceptionally large amounts of cyanide have been found in the soil around the Hanasaari power plant in Helsinki. The cyanide level was found to be 360 times above the legal limit.
The deadly compound is from the nearby former gas generating plant of Suvilahti, which used coal as its raw material. Ferrous cyanide waste was created during the cleaning process; the chemical dissolves in water in the very acidic soil. At the same time, cyanic acid is formed.
"It is a gaseous substance. It smells of bitter almond, and is deadly poisonous in very small doses", says environment inspector Erja Puntti-Hannuksela of the Helsinki Environment Centre. She says that the readings from samples near the Hanasaari B power plant were very high.
Soil analysis was conducted next to the Hanasaari B plant because Helsinki Energy has wanted to build a reserve heat centre. Depending on the acidity of the soil, the maximum recommended amount of cyanide in an industrial area is 50 or 100 milligrammes per kilo.
Helsingin Sanomat has learned that a sample was found in the area with a cyanide content of 18,000 milligrammes per kilo.
Helsinki wants to build a residential area next to the Hanasaari power plant for thousands of people. The area is largely land that has been reclaimed from the sea, with ferrous cyanide in the earth fill.
"It looks like cyanide has been put all over the place. It has been seen as a useful filler material", Puntti-Hannuksela says.
Helsinki plans to demolish the Hanasaari A power plant and move the pile of coal next to it away from what is to be a residential area. However, the city hs not yet investigated what kinds of toxins may lurk in the ground.
"I am very worried that cyanide might be found. If the amounts are the same at Hanasaari A as they are in Suvilahti, there will be problems. The cost of cleaning it up would probably be very high", Puntti-Hannuksela ponders.
In addition to cyanide, the soil at Suvilahti has been found to contain carcinogenic benzene and polyaromatic hydrocarbons (PAH compounds). The substances also come from the gas works, and the benzene factory that operated in connection with it.
The mounts of benzene that were found were tens of times higher than the maximum recommended amount. Under newer, tighter standards, the content exceeds the maximum limit by a factor of more than 100.
There have long been suspicions that ground water in the area has been contaminated by benzene. The ground water will have to be thoroughly purified in a very difficult process that could take decades to complete.
The Suvilahti area has not been planned as a location for residential construction. However, there are plans to set up cultural services for future residents expected to move in nearby.
Helsingin Sanomat
