2016-03-14 15:30:19
Since August 2014, the French departments of America (the Antilles and Guyana) have been facing successive waves of Sargassum seaweed strandings on their coasts. Despite the means of cleaning that have been put in place gradually, these algae decompose on the spot. Their decomposition leads to the production of hydrogen sulphide (H2S), toxic and strongly smelling gas, potentially detected at high concentrations.
A follow-up of complaints and health conditions, the measurement of exposure of affected populations, as well as prevention and information actions were set up in 2014. The monitoring unit of the regional health agency (ARS) of Martinique observes a notable increase in the number of medical consultations related to the health effects felt by the population chronically exposed to H2S. It also records reports from doctors, as well as complaints from local residents, private individuals or establishments open to the public located downwind of the groundings.
In this context, the ministries responsible for health, the environment and labor asked ANSES to carry out an expert appraisal on the emissions into the ambient air from decomposing Sargassum seaweed in the West Indies and Guyana. The opinion published today presents the first conclusions of the Agency’s expert appraisal: a state of knowledge on the health effects of H2S, as well as short-term recommendations relating to the preventive measures to be implemented to protect the workers in charge of the operations of collection, transport and treatment of the algae.
For this work, the Agency relied in particular on the knowledge acquired during previous work relating to the stranding of green algae, which can be widely transposed.
Agency conclusions and recommendations
The exposure of individuals to H2It takes place mainly by the respiratory route. Absorption via the oral and dermal routes is possible, but contributes only slightly to overall exposure.
If the effects in humans related to acute exposure (ie. for a short time) are well known (neurological and respiratory effects of increasing severity with exposure concentration), the effects related to exposure to H2S over longer durations are less documented. The first effects observed are irritative symptoms of the upper airways and eyes. Neurobehavioral effects and neurological symptoms (headaches, loss of balance and memory) are suspected. Moreover, in the current state of knowledge, given the small number of studies available, no conclusion can be drawn as to the potential carcinogenicity of H2S. Also note the strong odor nuisance associated with this gas.
In view of the data currently available, the Agency considers that its prevention recommendations, formulated during a previous expert appraisal concerning workers in contact with decomposing green algae on the coasts of Brittany (link to the opinion or the related article) , are to be considered for workers in contact with Sargassum algae.
Thus, the Agency recommends:
- the immediate implementation of the regular and systematic collection of seaweed washed up on the coast ;
- that building sites collection of algae are signpostedand theRestricted to operators;
- that population be informed health risks associated with exposure to H2S, especially near beaches where seaweed is decomposing. In addition, the population should be informed that seaweed should not be handled.
During seaweed collection, transport and processing operations, ANSES recommends:
- what each workerincluding in the cabins of mechanical machinery, is fitted with a portable H detector2Slocated near the respiratory tract;
- that workers wear personal protective equipmentin particular gas-filtering gloves, boots and half-masks, or a power-ventilated hood when the H concentration2S exceeds 10 ppm;
- to favor a mechanical pickuptaking into account environmental constraints;
- what training and information for workers are provided regularly;
- the implementation of traceability of exhibitor work.
The Agency also indicates that the implementation of a prospective epidemiological study focusing particularly on the exposure situations of the population at the local level would be useful and would make it possible to strengthen knowledge of the health effects linked to chronic exposures. at the H2S at low doses.
Finally, the Agency is continuing its expert appraisal work on this subject by investigating the ecology of Sargassum algae, their chemistry, their biodegradation and the kinetics of H emissions.2S and other substances, especially during the decomposition of these algae following stranding.
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