According to the Danish Ministry of the Environment, discharge of scrubber water from ships is a significant source of several of the heavy metals and tar substances that pollute the marine environment.
Scrubbers are systems installed on ships to reduce air pollution caused by burning fuel. They work by capturing pollutants like sulfur oxides (SOx) and particulate matter from the exhaust gas emitted by ships’ engines, and then discharging the scrubber water directly into the sea.
This, according to the ministry, has contributed to excessive levels of a number of heavy metals and tar substances such as lead, cadmium, anthracene and benz(a)pyrene in the marine environment.
Calculations from the Danish Environmental Protection Agency show that up to 20 percent of the discharge of nickel and 7 percent of the discharge of anthracene come from scrubber water.
Heavy metals in fish and shellfish for human consumption can have serious negative effects on humans in large quantities. For example, excessive amounts of lead can affect the development of the central nervous system, including the ability to learn and remember, while cadmium can affect the function of the kidneys.
When heavy metals and tar substances are discharged into our marine environment, they largely do not disappear and remain in constant circulation in the sea. The substances accumulate on the seabed and in the ocean’s food chains, and this is deeply worrying for our marine environment and our health.
… said Minister of Environment, Magnus Heunicke
The International Council on Clean Transportation estimated in 2020 that 68 million tons of scrubber water containing heavy metals and tar substances within 22 km of the coast in Denmark. This makes Denmark the country in the world where the sixth largest amount is emitted.
In addition, a new analysis from NIVA Danmark on the overall human pressure on Danish marine areas shows that environmentally hazardous substances are the third largest pressure factor for the marine environment.
The Minister of the Environment has now summoned the parties of the Folketing to negotiations on how the discharge of scrubber water can be banned. The minister will, among other things, present the parties with concrete models for possible legislative changes.