The Pilot Rivers: the only open-air laboratory

The Pilot Rivers were built in 1999 at the Platform for Experimental Research in Lacq (PERL). The facility comprises 16 artificial water courses, each 40m long. The only facility of its kind in Europe, this open-air laboratory, supplied with water from the Gave de Pau, can be used to accurately reproduce the ecosystem of that river, measure the potential toxicity of different compounds and test water monitoring systems.

"The water from the Gave de Pau is very good quality, ideal for studying the impact of discharge into the natural environment".

Anthony Yeun,
Engineer and Head of the Ecotox laboratory for the Environment and Sustainable Development department at the PERL.
 

The different phases of an exposure campaign

An exposure campaign lasts around three months. The first step is seeding. The Pilot Rivers team, which comprises two engineers and three technicians, diverts a small fraction of the water from the Gave de Pau toward the 100m-long nursery, full of pebbles, sediments and other natural substrates (plant substrates in particular). The nursery is constantly colonized by the organisms from the Gave de Pau. The water flowing out of the nursery is sent via an isoplan® distributor into the 16 channels, which will be colonized by the living organisms, fauna and flora. The colonization process takes just four weeks. Once the ecosystem has been perfectly replicated, we can move on to the next step, i.e. exposure, which also lasts four weeks. It involves evaluating the toxicity of different compounds - complex mixtures of products, hydrocarbons, metals, additives, discharge from purification - on the aquatic environment.
Step three is the natural recovery phase that lasts for a month after the exposure phase. Its purpose is to study the reversibility of the different phenomena. The data collected by means of various impact monitoring systems (sensors, water analyses, etc.) increasingly incorporate information produced by living organisms. 

"Water monitoring systems have considerably evolved over the last twenty years, from chemical to biological and then genomic-based monitoring techniques. The Pilot Rivers give accurate biological indicators, help assess the inherent risks of different substances and find alternatives to protect the receiving environment".

Patrick Baldoni-Andrey,
Head of the Environment and Sustainable Development department at the PERL.

An industrial chair in Pau, on the impacts of metals

Since 2019, the Pilot Rivers have been the subject of a partnership and an industrial chair with the University of Pau and the Pays de l’Adour (UPPA) and the Anglo-Australian mining group, Rio Tinto. The trio leads a shared research program on the impacts of metals on the natural environment. It involves studying their potential toxicity on the environment (quantity, form, etc.), using the reactions of living organisms to track exposure to metals. Their impact on the organisms exposed can be used to develop new molecular* tools, faster and more thorough than conventional approaches. By way of example, the shells of freshwater snails reveal the quality of the water in which they live and grow. Over the last four years, the chair has served to increase yet further our competencies in terms of in situ impact measurements: accuracy of eco-toxicological data, proof of low toxicity and zero impact, planning ahead for regulatory developments and the use of genomics tools in Company practices.

"In the past, we sampled the biofilms that formed on stones, to send them to morpho-taxonomists - biologists specialized in the classification and diversity of living things based on morphological criteria. Today, the same samples are taken, and their genomes analyzed using faster, cheaper and more effective approaches."

Yannick Corsellis,
Engineer and Head of the Ecotox laboratory for the Environment and Sustainable Development department at the PERL.

 
*What are molecular tools? They incorporate analytical approaches based on the study of molecules from a biological sample: DNA, RNA, proteins and metabolites are just some of the molecules stored in all living things.