Around the world with passive samplers

NIVA has developed a scientific partnership with the private research expedition Diomedes. Diomedes will, with the help of expert international scientists, sail around the world, and test methods to measure chemical pollution, sample microplastic garbage, and measure the abundance of endangered wildlife. NIVA's contribution is to coordinate chemical pollution monitoring using passive samplers.

Capturing contaminants

Diomedes will use passive samplers to detect contaminants in the water and in the air over time.

- The principle is simple: we use a highly absorbant silicone membrane that is exposed during up to two weeks, and that soaks in all the organic contaminants around it. Water samplers are attached under the hull of the boat, near the prow, where the water flow is strongest. Air samplers are at the helm, mounted on an arch 5m above the water, Diomedes states on their homepage.

La Sonate, a 15.6m steel-hulled two-masted sailboat built in 1980 in Biot, France, and the chosen ship for the yoyage. (Photo: Norith Eckbo)

- Since the detection of contaminants also depends on the conditions in the water and in the air, we continuously record the temperature and salinity in the water, and the direction, temperature and speed of the wind. This way, we can for example deduce where the air pollution was coming from.

- The boat was modified to allow deployment of silicone passive samplers on a special frame mounted on the wet part of the hull, says Luca Nizzetto, Research Scientist in NIVA. 

- The sampler will be deployed each time for about two weeks and will collect contaminants from water simply by diffusion. Simultaneous measurements of atmospheric concentrations will be conducted in collaboration with NILU and RECETOX (Czech Republic).

The expedition left Marseille early this year, bound on a tour of the oceans that should last 12 months at least, possibly more. The planned route will go through the Atlantic, down the warm current of Brazil into the Subantarctic waters, around Cape Horn, up the cold Humboldt current waters to the subtropical region, across the Pacific and the Indian oceans to the Cape of Good Hope, and up the cold current of Benguela and the beginning of the Gulf Stream into the Mediterranean.

Underwater at Bear Island.
(Photo: Ian Allan)

PS deploy
Deployment of passive samplers in Drammenselva.
(Photo: Ian Allan)

Path of passive sampling

Passive samplers for air and water have been exposed on the following paths (so far):

Gibraltar-Canary Islands
Canary Islands - Cape Verde
Cape Verde - Equator
Equator - Salvador, Bahia
Salvador, Bahia - Cabo Frio, Rio
The bay of Rio (ongoing)

The Diomedes-route, as of mid-August. (Graphics: Ian Allan).

The passive samplers are, during the yoyage, replaced with new ones, and the exposed ones are frozen.

- And just like that, we have our contaminant sample to send back to NIVA and RECETOX – where researchers Ian Allan, Nizzetto and Branislav Vrana will start the chemical analyses, Diomedes states.

Examining results from Diomedes in the RECETOX-lab. (Photo: Ian Allan).

This will also be performed by using different types of passive samplers mounted on the boat mast. Together these data will allow assessing whether Oceanic waters are acting as a sink of atmospheric contaminants emitted on land or they are restituting to the atmosphere the loadings accumulated in the past.

- This is a fundamental information for the interpretation of global air monitoring data run under the frame of the Stockholm convention and the  Convention on long range atmospheric transport, Nizzetto concludes.

The campaign will focus on analysis of persistent organic pollutants and PAHs.

>> Visit the expedition website

Sist oppdatert 22.08.2016