Although the practice of dumping radioactive waste into the oceans disappeared in the early 1990s, materials containing minimal levels of radioactivity are still allowed and regulated. Rules for dumping this type of materials into the oceans have become stricter following the adoption of an IAEA methodology aimed at protecting not only humans, but also the marine environment.
In a meeting held from 12 to 16 October in London, representatives of 87 countries agreed to set more specific thresholds on materials for dumping at sea. The venue was the 37th annual gathering of countries which are parties to the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, also known as the London Convention.
“This recently updated methodology includes a radiological procedure used to ensure not only the protection of humans, as in the past, but also the explicit protection of marine flora and fauna,” said Diego Telleria, Radiation Protection Specialist at the IAEA.
As described in the IAEA’s January 2015 publication, the concept, called de minimis, only allows dumping at sea of materials that are non-radioactive or cause such negligible impact to humans and marine organisms that it is of no regulatory concern.
To define the thresholds, IAEA experts used a dose that all marine organisms can tolerate, said Telleria. To do this, they considered three marine reference animals and plants which are the most prone to be exposed to radiation —flatfish, crab and brown seaweed— and established the maximum acceptable concentration of radioactivity based on these species’ level of tolerance.
The 2003 guidelines on the application of de minimis, published by the International Maritime Organization (IMO), will be updated to incorporate this new methodology. The actual thresholds will not change as a result of the update to the regulations, as the calculations revealed that the limits set for humans had also in effect already protected the environment. “At the request of parties to the Convention and addressing the concerns of environmental groups, the protection of flora and fauna has now been made explicit,” Telleria said.
Inventory of Radioactive Waste Dumping
The IAEA has acted as the technical advisor on radioactive matters to the Convention for more than 40 years. This month, it published a comprehensive inventory of human-made radioactive sources entering the ocean since 1946.
Developed by the IAEA in cooperation with the IMO, the ‘Inventory of Radioactive Material Resulting from Historical Dumping Accidents and Losses at Sea’ compiles past waste dumping, accidents and losses at sea involving radioactive material recorded since the 1940s and 1950s up until 2015.
The inventory will serve as the official record for the London Convention and help scientists to evaluate the impact of radionuclide sources in the marine environment anywhere in the world, Telleria said.
The IAEA periodically gathers information from its Member States to track the amount of radioactive materials that have entered the world’s oceans and seas and assesses their loss of radiation, or radioactive decay, over time.