SafeNano

Effect of water and wastewater treatment on the properties of engineered nanomaterials (ENMs) in the context of their fate, toxicity and interaction with other contaminants (H2020-MSCA-IF-2015, No. 699794))

 
SafeNANO Intro

Research methodology

Aim (a) (WP1). Modification of the properties of ENMs under the influence of advanced water treatment methods. H2O2, UV, chlorination and ozonation are currently the methods most frequently used for the purification/treatment of water and wastewater. It should, therefore, also be expected that during water purification/treatment there would take place processes changing the properties of ENMs. In this context it is important to determine what properties of ENMs will be affected by those processes, which will allow the determination of the effect of those changes on the fate and toxicity ENMs as well as interactions of ENMs with other contaminants. Modification of the ENMs properties under the influence of advanced methods of water and wastewater treatment will be conducted in the photochemical reactor. The effect of four different techniques of water/wastewater treatment (UV irradiation, H2O2, chlorination and ozonation) on ENMs properties I am going to investigate. The studies will be conducted using different ENMs in two water matrices: distilled water and modelled wastewater (to determine the effect of natural organic matter on the ENMs changes). Selection of the ENMs for this project is based on: (a) toxicological relevance and (b) range of production and application. According to these points I selected graphene nanoplatelets and nanohybrids (NHs) (Figure 2). The impact of the treatment on physicochemical properties of the ENMs is examined by methods presented in Figure 2. The ENMs properties will be determined before and after treatment.

Figure 1.  General outlook on the project tasks

Aim (b) (WP2). The effect of treatment processes on fate treated ENMs in laboratory and mesocosm. Changes in the physicochemical properties of ENMs should result in a changed behavior of ENMs. This would affect ENMs’ ability to aggregate, interactions with biota and biotransformation. The most important parameter characterizing ENMs is their ability to aggregate2, which affects mobility, bioavailability, and toxicity. Aggregation is influenced by NOM, cations or pH. The ENMs behaviour will be investigated in laboratory and in mesocosms experiment. The ENMs aggregation studies will be conducted in laboratory by shaking the solutions of ENMs. ENMs stability will be determined using UV-Vis spectroscopy, TOC analyser8 and DLS technique depending on ENMs. Effect of the pH and NOM and different cations on aggregation abbility will be also evaluated. In the mesocoms experiment selected ENMs obtained and characterized during WP1 will be added to the mesocosm facility (CMF). CMF is home to simulated wetland ecosystems, enabling a wide array of uniquely realistic investigations into the mechanisms that govern ENMs transport, transformation, ecological interactions and biouptake. CMF mimics an emergent freshwater wetland environment. The mesocoms facility was described in detail in9. At the end of the 12-month study period, the concentration of ENMs in plants and insects will be determined to assess the long-term bioaccumulation of the transformed ENPs.

Aim (b) (WP2).

Aim (c) (WP3). Interaction between well-known contaminants and ENMs. Changes in physicochemical properties may result in stronger or weaker adsorption of contaminants on ENMs. Adsorption is a key process determining the fate of many pollutants10. Detailed knowledge of adsorption mechanisms may be used in the prediction of the mobility and bioavailability of pollutants. The previous research concerning sorption of contaminants by ENMs has been, however, conducted on fresh ENMs11. Here I am going to investigate selected ENMs (especially carbon nanotubes, graphene or NHs) before and after treatment. Phenanthrene (PHEN) and triclosan (TCN) as well as will be the model compounds because they are frequent contaminants in waters, thus their potential contact with ENMs is obvious. PHEN has been selected due to the fact that numerous studies on its sorption by various materials (including pristine ENMs) have been conducted. TCN has not been investigated so far, and the results obtained will expand our knowledge on its fate and on the mechanisms of its binding by ENMs. The adsorption isotherms will be obtained using a batch equilibration technique12. Sorption and desorption kinetics will be also determined.

Aim (d) (WP4). Risk assessment of ENMs in the context of their transformation. While we now have a fairly large knowledge about the toxicity of non-transformed ENMs, absolutely there is no information in the literature about the potential toxicity of ENMs that have been transformed. There is also no information on the toxicity nanohybrids (both pristine and modified). Transformations can affect many of the ENMs properties, which change both bioavailability as well as mobility of ENMs and thus also affect toxicity. During the WP4 I am going to conduct a series of experiments involving different living organisms to determine how the change of the ENMs properties affects their toxicity. Quantitative information (e.g. dose response) will be obtained to document potential toxicity from different ENMs. From three to five ecotoxicological test with alga, plants, bacteria and invertebrates will be  selected for this WP (Figure 4). The selection of the particular test will be done after obtaining of results from WP1-WP3.

Figure 2.  Engineered nanoparticles investigated in connection to environmental issue

Figure 3.  Investigated compounds: a) triclosan, b) diclofenac, c) naproxen, d) caffeine, e) phenanthrene

a)

e)

d)

c)

b)

Figure 4.  Examples of organisms that will be tested