The ability to use UNOLS vessels to collect samples for natural level isotope measurements as well as to conduct experiments requiring the addition of labeled isotopic compounds (enhanced radioisotope work) is important for the ocean science community. Radioisotope solutions used in enhanced radioisotope experiments are 10 to 12 orders of magnitude more concentrated than natural levels. Therefore, even a minute amount of enhanced isotope solution can devastate natural abundance work. This makes collecting samples for natural level studies on ships that have also hosted enhanced radioisotope experiments a precarious business.
Ship Operators are required by State and Federal regulations to keep their vessels clean enough to meet the Health and Safety standards. However, the limits for natural abundance work are much lower. Minimizing or eliminating contamination at these levels takes special effort on the part of the enhanced isotope scientists and the ship operators/technicians. Shipboard radioisotope users must have a heightened awareness to prevent any sort of contamination.
The UNOLS Radioisotope Awareness program was developed to promote awareness of potential problems and give ship operators tools to share with their users in an effort to keep the UNOLS vessels clean for all science.
Creating awareness about the potential problems that enhanced radioisotope use can cause is the first step. As stated, Health and Safety standards, as outlined in training to become an Authorized Radioisotope User, does not go far enough. The Natural Abundance Community has put together a short memo “Enhanced Radioisotope Use Affects on Natural Abundance Work” that describes the problem. This is to be shared with the enhanced isotope PI in the pre-cruise planning process. The PI should share this along with the “UNOLS Radioisotope Contamination Awareness” presentation with the authorized users within their team prior to deployment. The presentation shows the users how their work affects others while also giving them tips on how to avoid contamination. A separate, more concise presentation for the crew and technicians points out their role in keeping their ships clean.
It is also recommended that the operator conduct a shipboard radioisotope briefing prior to radioisotope use. Unlike the pre-cruise planning which generally involves only the PI/Chief Scientist, this briefing should include ALL authorized radioisotope users. The briefing will serve as a review of the shipboard policies of radioisotope use and the users’ roles and responsibilities in the process. It is also one more chance stress the fact that the ships are multi-use platforms and care must be taken to keep them clean for all users.
Standard swipe tests required for health and safety do not have detection levels low enough to detect contamination that can affect natural abundance work. Further, most swipe tests are conducted only inside or in the immediate vicinity of the radioisotope van. For these reasons, the NSF funds Operation SWAB to conduct SWAB tests within the radioisotope vans and throughout the UNOLS vessels. This program uses a much more sensitive test methods and detection instrumentation. More information on Operation SWAB can be found on their website: http://www.rsmas.miami.edu/groups/tritium/swab/monitoring-of-shipboard-contamination/.
It is recommended that the SWAB team conduct a full assay (radvan and ship) after each cruise where radioisotopes are used. On vessels where radioisotopes are used more than three times per year, it is recommended that full SWAB assays are conducted at least biannually. It is up to the operator to contact the Operation SWAB team to set-up the visit(s). All SWAB test results will be posted to the UNOLS Radioisotope Use Logs (see below).
It is also recommended that the PI/head Radioisotope User conduct 2-3 SWABS within the radvan prior to departure. This will help verify that the van is indeed clean. Operation SWAB can provide the ship operator with Courtesy Kits (everything but the bucket!). SWAB tests run on a shipboard LSC should be run for at least 15min and it is recommended that as much of the sample be mixed with the scintillation cocktail as possible (as outlined by the scintillation cocktail vendor).
In order to better serve the natural abundance science community, each vessel will have an online Radioisotope Use Log that will list when, who and what radioisotopes were used onboard. Additionally, any SWAB reports for that vessel will be posted.
The UNOLS research vessels are multi-use platforms that support both enhanced radioisotope use and natural abundance work. In order for these two science disciplines to work harmoniously, special care must be taken on the part of the enhance radioisotope users and the vessel operators/technicians. The tools introduced above should help to enhance awareness of the problems that very low levels of radioisotope contamination (lower than health and safety risks) can cause and can help the operators and scientists keep the ships clean for all scientific research.