Contribution of mesocosm testing to a single-step and exposure-driven environmental risk assessment of engineered nanomaterials

Differential Reactivity of Copper- and Gold-Based Nanomaterials Controls Their Seasonal Biogeochemical Cycling and Fate in a Freshwater Wetland Mesocosm

“…Using dissociation constants in pure water as model inputs for NPs presenting relative dissolution stability may not be an appropriate proxy to capture the behavior and impact of metastable ENMs in the environment. 3,58 Predicting the fate of ENMs in complex ecosystems that are shown to be inert in relatively pure (ligand-free) aqueous systems will require a better understanding of their metastable character, the biotransformations that may occur in each ecosystem sink, and their transfer between compartments. 15,59,60 ■ ASSOCIATED CONTENT…”

“…1,2 They provide realistic information about behavior, transformation, and impact of contaminants in a comprehensive experiment. 3 The majority of the early mesocosm studies used relatively high-concentration one-time pulse additions of ENMs to enable tracking their fate and to observe system changes. It is now known that high particle concentrations influence their sedimentation, dissolution, exposure routes, and ecosystem impacts that may ultimately occur.…”

Monitoring the Environmental Aging of Nanomaterials: An Opportunity for Mesocosm Testing?

“…Mesocosm testing is an increasingly popular alternative to traditional procedures for examining the environmental risks of nanomaterials, because (i) by design, it accounts for system complexity to a level that no other single test does, and (ii) multiple exposure and hazard parameters/end points can be characterized in a single experiment, based on real time monitoring (e.g., multi-parameter probes) and off-line analyses [12,13,14,15,16,17,18,19]. The general strategy behind mesocosm testing is in sharp contrast with detailed parameter/end-point determination; while strict control of every aspect of the procedure is at the core of a traditional standard, mesocosms are expected to evolve freely after their set-up and stabilization period [13] for durations of at least several weeks, and up to a year or longer in some cases [18,20]. The obvious benefit of this testing method is an unparalleled environmental relevance (assuming adequate scenarios of contamination) compared to any other standard or guidance document.…”

How Microbial Biofilms Control the Environmental Fate of Engineered Nanoparticles?

“…Particularly well-suited experimental units with which to engage such multidisciplinary teams are mesocosms, that consist in mediumsize replicated ecosystems (Crossland and La Point, 1992;Shaw and Kennedy, 1996;Food and Agriculture Organization, 2009). Mesocosms experiments can be designed to mimic any ecological scenarios of exposure (Auffan et al, 2019) and in the scope of ENP studies, have been defined as indoor or outdoor experimental systems containing a portion of the natural environment which is (i) self-sustaining once set up and acclimatized without any additional input of nutrients or resources, and (ii) that allows monitoring of all (or the maximum of) input and output parameters to measure changes in the environment, and in the concentration and speciation of ENPs over time, space, and ecosystem compartments (Figure 4).…”