MARIGOT: After an alarming report published last Monday by the Regional Health Agency (ARS) concerning the levels of hydrogen sulfide emitted by the sargassum stranded in Cul-de-Sac, new measurements were taken in the middle of the week with results in clear improvement.
Following the massive stranding of sargassum in Cul-de-Sac, the president of the Collectivity, Louis Mussington, had requisitioned by emergency order on July 27 the intervention of several companies in reinforcement to carry out an intensive collection of algae in this area. The levels published in the ARS report on Monday 1 August are high: 4.8 ppm at 5 meters from the sargassum groundings and 3.2 ppm at the level of houses.
Following these worrying results, the services of the Prefecture decided to carry out new measurements suspecting the rates to be influenced by the strong gas emanations related to the fact of stirring up algae in the process of collection. Recent readings of hydrogen sulfide in Cul-de-Sac confirm this hypothesis, says Fabien Sésé, secretary general of the prefecture of Saint-Barthélemy and Saint-Martin. “We note a positive trend following the latest measurements taken.” Indeed, the levels are down: 2.2 ppm near the stranding areas against 4.8 ppm last Monday.
At the level of the houses, the new readings indicate a level of Hydrogen Sulfide of 1.4 ppm, more than half of the 3.2 ppm measured last Monday. If the intensive collection is an efficient process, many inhabitants of Cul-de-Sac wish that a more perennial solution be put in place to prevent other massive strandings which have undeniable consequences on the quality of life and the health of the surrounding population. The recommendations of the ARS for measurements between 1 and 5 ppm are to stay away from sites affected by the stranding of decomposing sargassum.
Beyond 5 ppm, a rate which was almost reached last Monday, the ARS recommends the evacuation of the zones at risk. New measurements will be made this Friday, August 5. As for the forecasts released by Météo France at the beginning of the week, the risk of grounding was average for Saint-Martin and Saint-Barthélemy, where numerous rafts were detected to the east and immediate south-east of both islands. Many seaweeds will transit near the islands or strands on the shoreline exposed to the flow during the coming week.