Monitoring of Radionuclides in Ship Ballast Water Following the Fukushima Nuclear Accident

Ballast water is the waters taken into the ship compartment to provide stability. It is taken on board at the port before the voyage begins and discharged at the port of call (arrival) while loading cargoes. Ballast is primarily composed of water and is full of stones, sediment, and thousands of living species. The quantity of water taken depends on the size of the ship and it can reach up to 10,000 tonnes. As a well known fact, Daiichi nuclear plant in Fukushima had released radioactive contaminated water into its surrounding sea and being dispersed by currents and tides. Therefore, ships travel between Malaysia and Japan in particular those from the affected regions and travel to Malaysia without cargoes will have a risk of transporting back radioactive contaminated water from Japan and released it at local ports. Malaysian Marine Department with the cooperation of Malaysian Nuclear Agency have been analysing the concentrations of several radionuclides in the ship's ballast water and sediment. This is to ensure the effective dosage is safe to the crews and general public as well to fulfill the permissible limit of 1 mSv/yr gazetted by the authorities. It is also to monitor that the contaminated water is not discharged into our marine environment. (author)