CONICET | Buscador de Institutos y Recursos Humanos

The transport of NMs in different environmental compartments is difficult topredict as it depends on the physical and chemical characteristics of the NMs. NPsmay strongly sorb to the soil matrix due to their high surface area and they canthus accumulate in the soil. In the atmosphere, NMs behavior depends on theduration of time that particles remain airborne, their interaction with otherparticles or molecules in the atmosphere and the distance they are able to travel inthe air. With different processes, such as diffusion, agglomeration, wet and drydeposition and gravitational settling, it is really important to understand thedynamics of ENPs in the atmosphere. At the same time, ENPs transport in water isinfluenced by aqueous solubility, reactivity of the ENPs with the chemicalenvironment and their interaction with certain biological processes due to theirlower mass. There are some general transportation trends of NPs, which are theninfluenced and ultimately controlled by any transformation they undergo.Transformations of NMs are unavoidable and will readily occur in differentenvironmental compartments greatly affecting their physicochemical properties,toxicity and transport. Properties of the transformed NMs will ultimately dependon the environment in which they are entering and the order of environmentalexposure which can be directly through pristine NMs or indirectly through edibleorganisms to humans. As regards to the toxicity, some transformations mayenhance toxicity potential (e.g. chemical weathering of the shell of a Cd-Se QDsthat releases toxic ions from the particle core), or reduce toxicity (e.g. adsorptionof NOM decreased the short-term bactericidal effects of C60, Ag NPs).There is still a vast uncertainty about the life cycle of NMs transformationsand their exposure. Transformations can lead to materials that can be moreheterogeneous than the parent NM itself, making characterization difficult. Hence,it is really important to develop analytical methods to track NMs efficiently atlower concentrations and to determine the rate and extent of transformations ofNMs under realistic conditions. Recent years have seen a growing interest in theaspects of bioaccumulation trophic transfer and bio concentration. However,despite the growing efforts, knowledge of bioaccumulation and bioconcentrationof NMs is still rudimentary, and it is difficult to draw a general conclusion. This isdue to several reasons, mainly a lack of analytical methods to monitor the fate ofNPs in the environment, impossibility to envelop a standard protocol that wouldallow comparison across studies and lack of a long-term study. The majority of theresults are obtained under laboratory conditions, and it is difficult to extrapolate tonatural circumstances due to the great number of environmental variables that candrive NMs reactions. Thus, it is very important to study the NPs and the hostorganisms in each case since contradictory results arise from different propertiesof each NP and each type of environment. Therefore data will remain bounded tolab experiments.