2013-01-03 09:00:09
Episodes of massive proliferation of macro-algae on European coasts and beaches were reported in the scientific literature as early as 1905 on the Irish coasts. Over the past forty years, this phenomenon has continued to grow. The proliferation of these algae is mainly linked to the presence of nitrates, brought by human activities (especially agriculture), in the waters and to the topographic configuration of the coastline (bays).
Once washed up on the beaches, these massive deposits of algae lead, during their putrefaction, to significant releases of gases, in particular hydrogen sulphide (H2S) which can cause olfactory nuisances and health problems for walkers and beach residents. In order to remedy this situation, certain beaches are subject to collection, the algae being then treated inland. These different stages expose workers to these gases.
The work of the Agency
Emergency referral in February 2010 by the health authorities as part of the national plan to combat green algae, the Agency initially provided recommendations for professionals involved throughout the elimination process. of these algae.
In order to limit emissions due to their putrefaction, the Agency has indicated that these algae must be collected “fresh”, that is to say within 24 hours, or even within 36 hours, following stranding and then treated. within 48 hours. Beyond these deadlines, emissions risk being such that collecting, transporting and processing them requires implementing very restrictive means of protection. Regardless of the state of decomposition of the piles of algae, workers must equip themselves with a hydrogen sulfide detector (H2S) and mark collection and storage sites in order to keep walkers away.
Following this first opinion, and in order to better characterize exposures, ANSES carried out measurements of gas emitted by green algae in the process of putrefaction during the summer of 2010. On this basis, a report and an opinion supplementing the Agency’s first recommendations were produced in spring 2011. This work made it possible to reinforce several of the recommendations formulated in 2010. Firstly, ANSES recalled that by avoiding the proliferation of green algae, risky situations due to masses of putrefied stranded green algae would arise in fact limited.
In order to avoid the rotting of algae and the gas emissions associated with it, ANSES emphasizes that, in accordance with its first recommendations, the collection, transport and handling of algae in treatment centers must be done as quickly as possible. The available observations do not allow us to know precisely the time from which fermentation gas emissions become significant, particularly given the large number of parameters influencing this decomposition. However, the data indicates that a delay of more than 48 hours does not allow risky situations to be avoided.
The Agency also recommends favor mechanical collection and indicates that it must be carried out under conditions that minimize public exposure. Marking of collection sites is thus recommended by the Agency.
For certain stranding areas that are inaccessible for collection and therefore constitute risk areas, the Agency recommends that information be made available to users, walkers and residents of beaches.
For professionals involved in the collection-transport-processing process of green algae, whatever their status, including seasonal staff, ANSES recommends in particular wearing a personal portable hydrogen sulphide detector (H2S). The Agency also recommends that these personnel receive adapted information and training and that their exposures are recorded in their medical records.
Finally, the expertise carried out by ANSES having been limited by still incomplete knowledge in certain areas, the Agency recommended the acquisition of additional knowledge which will in particular make it possible to better characterize gas emissions by green algae and their evolution over time, to better understand the exposures and toxicity of the different substances emitted to go even further in the assessment of the risks linked to green algae.
1698056615
#Green #algae #risks #neighboring #populations #walkers #workers #Handles
