engleski

Role of marine gel in scavenging and stabilizing silica nanoparticles in the marine environment

The stability of engineered nanoparticles (NPs) in the marine environment plays an important role in determining their environmental implication and potential risk to marine biota and eventually to human health. In order to understand the behavior of NPs in the marine environment, it is important to understand possible mechanisms involved in NPs interaction with the naturally occurring seawater components, particularly natural organic matter. Marine gels are three-dimensional networks of solvated biopolymers occurring in seawater and they present important fraction of organic matter in ocean system. We studied the role of marine gel in scavenging and stabilizing engineered SiO2 nanoparticles (SiO2 NPs) in the marine environment using atomic force microscopy (AFM) to visualize topography and aggregation level of the nanoparticles as well as dynamic light scattering (DLS) as a complementary technique. Marine gel biopolymers displayed strong interaction with SiO2 NPs and the incorporation of individual NPs into the gel network was visualized by AFM. DLS results confirmed stabilization effect of marine gel showing that majority of NPs existed as single dispersed NPs. On the contrary, SiO2 NPs dispersed in seawater without presence of marine gel or EPS showed enhanced aggregation of SiO2 NPs that was visualized by AFM and confirmed by DLS measurements. Our results indicate that the presence of biopolymers assembled in gel networks changes the fate of SiO2 NPs in the marine environment. By scavenging and stabilizing SiO2 NPs marine gel could prolong their presence in water column and make NPs available to higher organisms. This is the way how SiO2 NPs (and most likely other engineered NPs) can persist in water column, in spite the fact that SiO2 NPs quickly aggregate in seawater.

marine gel ; silica nanoparticles ; marine environment

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