Unless exceptional events cause effects directly visible to the naked eye, air, and water pollution remain mostly imperceptible. The frequent absence of external signs when pollutants are present, and their ability to blend with other bodies, generate phenomena which are hardly discernible for who doesn’t possess the adequate equipment. Ozone in air and metallic pollution in water, for instance, cannot be noticed immediately. Furthermore, the physical and chemical properties of those contaminants contribute to produce specific moving geographies that escape our ordinary detection devices.
Until the end of the 1980s, the observation and monitoring of pollution rested on conventional chemistry methods that permitted to identify and assess concentrations of contaminants in the atmosphere, water, or sediments. If such analyses give indications on the presence or absence of one particular pollutant, they do not tell us its impact on living entities and natural environments, nor the effects of the accumulation of low doses, or the compound effects of several pollutants.
As a young and controversial discipline, ecotoxicology developed new observation instruments that allow to diagnose precisely the corruption of the quality of water or the degradation of specific environments. The observation techniques set up by ecotoxicology researchers rely on the sensitive and adaptative abilities of some living entities identified as "sentinel organisms" (providing bioindicators and biomarkers). In 1926, pioneer scientists started drawing up the map of atmospheric pollution by investigating lichen populations. At the end of the 1960s, the USA launched a sea water surveillance program by enrolling mussels in research protocols (Mussel Watch Program). If the presence and distribution of species provide important indications, the study of the biological responses those species produce in reaction to environmental perturbation supply information that are even more precise. Physiological, biochemical, and genetic tests are performed on "sentinel organisms" to reveal and make explicit the presence and impact of pollutants.
The living entities used by ecotoxicologists are not mere instruments or guinea pigs. They are rather partners that lend their sensitive qualities to the researchers. They are not interchangeable either. Each contaminated site and each type of pollutant require specific mediations, involving different experiments and "sentinel organisms." The information collected from several tests allows ecotoxicologists to develop observation devices that are so sharp that they can monitor the variations of toxicity in time and space.
This research project aimed at examining three main questions while studying the history of ecotoxicology and scientific controversies that have marked its evolution, and performed ethnographic fieldwork in two laboratories, in France and Germany.
- What was the evolution of observation methods and problems posed by the enrolment of living entities in research protocols? How doed the extension of laboratories, from the setting of observation devices to their use in situ, and the extension of the instruments to "sentinel organisms," contribute to the transformation of scientific practices? What are the constraints? How to account for the participation of those living entities as research auxiliaries?
- What were the steps permitting one to materialize and provide evidence of insidious pollution through the use of "sentinel organisms." Ecotoxicologists construct reduced models in their laboratory to target their experiments before testing them in the field. What are the differences between controlled observations made indoor and observations made in natural environments? How can they be scientifically related? What visualization methods are used? Has the status of evidential documents changed along the history of the discipline? What sort of evidence do they provide, and which type of rhetoric is then needed to transport them?
- What were the epistemological and political consequences of the emergence of new experimental devices marked by features that are mostly local and subject to great variations? It seems that each environment, each contaminated site, each type of pollutant, requires adapted testing protocols. At the same time, each pollution phenomenon contributes to produce its own propagation space. Then, ecotoxicological experiments reinforce the attachments between scientists, specific places, some pollutants and species. What are the obstacles to the standardization and implementation on a large scale of those new observation and monitoring instruments? How do local claims actually transform into general? What are the consequences for our conception of objectivity and politics?