Meeting with a specialist

Meeting with Olivier Tostain

‘Birds come and nest close to the launcher’

Olivier Tostain is an administrator of the ‘Réserves Naturelles de France’ where he represents natural parks for French overseas territories. He has been involved in creating most of the protected areas for the French Guiana department.

Olivier Tostain has been a bird enthusiast ever since he can remember and his hobby has become his profession : learning more and more about bird biology and behaviour.

Olivier Tostain, who has a university degree in ecology, created the environmental research unit ‘Ecobios’ as a business in French Guiana. In 1993, the Guiana Space Centre asked him to evaluate the effects of alumina pollution from Ariane 5 launches on wild animals.

‘To do this, explained Olivier Tostain, I had to find a reliable model for analysis. The analysis of the internal organs of mammals, reptiles or birds turned out to be unsuitable as it was not possible to compare the data because the results varied too greatly. Moreover, taking samples of internal tissues meant killing the animals which would have been a real ethical problem. On the other hand, bird feathers turned out to be the appropriate model as they enabled us to collect reliable, homogeneous results for each station, and also to easily capture animals without wounding them and then release them immediately.’

Control sites

Plume samples are systematically taken for each launch since the first Ariane 5 was launched. For the last two years, the studies have only been done once a year as the results appear to be homogeneous and relatively comparable from one campaign to another.

About fifteen birds (Lesser Seed-finches, kikiwis, white-winged tanagers, hummingbirds, manakins, kingfishers, etc.) are captured with nets, at each of the different sites located at increasing distances from the launch pad along the axis of the combustion exhaust gases from the boosters: at distances of 300 meters from Ariane launch complex no.3 and then 1.5 kilometres, 6 kilometres or even more.

Several control sites have been analysed such as the forests on the white sand of Mana, the Anse golf club, the Kaw mountain, urban areas, the piste de Saint-Elie (the Saint-Elie track) etc. The different locations of these sites make it possible to compare results.

“According to the control sites,” continues Olivier Tostain, “we found great variability in the results. Compared to all the other sites, the Kaw Mountain and urban areas receive higher doses of alumina. In forests, these doses may be due to the geology since laterite has a lot of natural alumina. Urban pollution might explain the high doses observed at Montjoly.”

Healthy birds

The results of studies at the Guiana Space Centre have shown that in an area very close to the launch pad, doses are lower or equal to those found on sites where there are the highest natural concentrations of alumina such as forests on the laterite crust.

Further away from the launch pad, the doses gradually decrease until, when more than 5 kilometres away, they are ‘diluted’ in the ‘background noise’ of ecosystems. <
In order to refine his research, Olivier Tostain has tried to demonstrate that alumina accumulates over time. However, birds apparently assimilate it well and then excrete it as no accumulation has been observed.

A lot of people think, especially Olivier Tostain, that it would be too much to hope for and impossible for Ariane 5 launches not to affect the avifauna, nevertheless for 8 years already, the birds captured have been found to be healthy. They continue to nest, to sing, with a reproduction rate which appears to be similar each year. Some species, such as the Aras (parrot family) which are nevertheless quite vulnerable, even come to nest on the CSG site, close to the launch area.

‘I would now, concludes Olivier Tostain, like to do more research on the possible combined effects of alumina and hydrochloric acid on birds, by studying in particular the resulting availability of calcium. Given their good general state, there should not be any direct significant effect but there might be indirect effects in the long term. Depending on the results, I believe that these studies might also apply to people. I find my work extremely interesting and I hope that it will be continued.’