Environmental monitoring is a major challenge for modern society. Most of the methods currently in use are based on physico-chemical analytical principles. Although they are very powerful for determining specific parameters of an environment (such as pH, specific molecules, etc.), they do not allow us to assess biological parameters such as the fate of molecules in the environment, or their impact on the biosphere. Also, over the last few decades, several teams around the world have proposed solutions to this challenge. However, the question of representativeness remains unresolved. These biological parameters are the result of a close relationship between one (or more) molecule(s) and a target (organism, community, ecosystem). However, the metrological approaches proposed are very often based on monospecific approaches using a single biological sensor (such as the ISO 11348 standard toxicity test based on Aliivibrio fischeri) or on complex, uncontrolled communities (OECD 209, 301). In this context, the data interpretation can be complex and the results transposition to an environmental context can appear hazardous, because of the lack of representativity. In order to increase the representativity of biological approaches, the GEPEA laboratory has been developing fluorescent biosensors based on multi-specific approaches using several bioreporters. To achieve this, the choice of biological sensors is at the heart of the metrological strategy and is based on in-depth knowledge of the target ecosystem. This type of approach has been deployed in response to a number of issues (assessing the persistence of molecules, estimating toxicity) and in different environments (maritime coastline, domestic WWTP, industrial WWTP).