Participation of the Belgian airborne surveillance in the monitoring of chemicals during French MANIFESTS Sea Trials and monitoring of ship emissions at the ECA border

From 30 May to 2 June, the Belgian aerial surveillance aircraft carried out an international mission to Brittany in France. The aircraft is owned and operated by the Royal Belgian Institute of Natural Sciences (RBINS) and is frequently used in Belgium in the framework of the Coast Guard. International missions are also on the agenda. The purpose of this mission was twofold: the aircraft took part in an international sea trial for the detection and monitoring of chemical pollution and checked with the sniffer sensor the air emissions from ships at the border of the Emission Control Area (ECA) for compliance with the international emission regulations laid down in the so-called MARPOL Annex VI.

Slick of a chemical product behind the SAPEUR, as observed by the Belgian coastguard aircraft.


In contrast to the increasingly less frequent occurrence of oil pollution, pollution by other chemical substances at sea is steadily increasing. As a result of the increasing transport of chemical products by tankers, and the complex international legislation (MARPOL Annex II) allowing the discharge of certain substances under specific conditions, the impact of chemical pollution on the marine environment is also showing an upward trend.

The variety of transported chemicals is large, which creates many challenges for the authorities responsible for monitoring and enforcement. Among other things, the detection and identification of chemicals on the sea surface by airborne units is very complex. In addition, there is still insufficient knowledge about the behaviour of different chemicals at sea, which complicates the modelling of the drift of these pollutants in time and space.

The project MANIFESTS (MANaging risks and Impacts From Evaporating and gaseous Substances To population Safety) tries to meet these challenges. For this project, the main categories of transported chemicals were identified. Different sensors were tested for their ability to identify different substances.  This was first done in a laboratory environment, but the ultimate test was a sea trial where sensors were tested on ships and on flying units. The focus here was on highly evaporating substances.

From the ship ‘SAPEUR’, various chemicals (in limited quantities) were discharged in a controlled manner over two days at the test site near Brest.

During the exercise at sea, different substances were discharged into the sea (in limited quantities), after which they were observed by different flying units. The Belgian coastguard aircraft was one of four aircraft used in the exercise, alongside the Spanish and French coastguard aircraft and a research aircraft of the French Office National d’Etudes et de Recherches Aérospatiales (ONERA). The coastguard aircraft were mainly used for slick mapping (for the purpose of modelling), and for detection by radar and infrared. The ONERA aircraft was equipped with 2 hyperspectral sensors specially developed for the detection of chemicals both on the water surface and in the atmosphere (gas clouds).

The exercise at sea went well and the Belgian coastguard aircraft was able to make a constructive contribution to the collection of field data. It is now up to the scientists to fine-tune the models and to optimize the sensors so that chemical discharges can be better monitored in the future.

Slick of a chemical product behind the SAPEUR, as observed by the Belgian coastguard aircraft.

The RBINS (Marine Forecasting Centre/MFC) is involved as partner in the MANIFESTS project. It is mainly responsible for the further development of mathematical models that can simulate the drift, behaviour and fate of harmful substances other than oil (so-called HNS – Hazardous and Noxious Substances). The aim is to reduce the knowledge gaps of in-house models by implementing the newly acquired knowledge on evaporation, fire and explosion processes of gases and evaporators, and by carrying out a thorough inter-comparison and validation exercise of models to better understand their strengths and weaknesses. The RBINS also contributes, among others, to the development of a decision-support system (DSS; proof of concept) that will integrate useful information such as model simulations, an HNS database, vulnerability maps, etc. with the aim to facilitate the crisis management of HNS incidents by competent maritime services.

Infrared camera picture of a chemical slick.

Monitoring of ship emissions at the ECA border

The MANIFESTS Sea Trials took place just west of Brest, in French waters. Since this is also the zone where the ECA border is located, where ships have to switch to low-sulphur fuels when entering the area, it was decided to combine the participation of the Belgian Coast Guard aircraft in the MANIFESTS exercise with a check for violations of the international regulations on ship emissions. A total of 62 ships were checked during the mission. 18 of these were in the immediate vicinity of the ECA border, the other vessels were observed on the way to and from Brittany. Of the 18 vessels at the border, six showed suspicious sulphur levels, while two had high NOx emissions. One vessel was found with both high NOx emissions and high sulphur content in its fuel. Not all of these observations concern violations as some vessels were observed just outside the ECA, although most likely their emissions were already above the limit during the last part of their passage in the ECA.  A more detailed analysis has yet to be carried out, but these preliminary results clearly indicate that increased monitoring at the ECA border could be very useful for improving MARPOL Annex VI enforcement. Belgium has been a leading international player in this area for years and is trying to create support for this with other North Sea coastal states, within the framework of the Bonn Agreement. One of the Belgian proposals is to jointly organize intensive control campaigns at the ECA border. This mission can already serve as an interesting case study to demonstrate the importance of such type of campaigns.

Air emissions of a container vessel.