Also, in addition to my previous questions to your comments (please check and let me know soon), I have the following opinion.<br />While you mentioned you deleted much contents in the introduction due to repetition, I'm asking you should consult with me prior to deleting the contents, because I need to keep the introduction section as it was due to several reasons. So I need you to edit the introdctuion again without chaging any structure, please.<br />I have the due and need to get this soon. please edit the following introdction and send it to me as soon as possible I need to hurry up.<br /><br />I attached it as a word file<br /><br />INTRODUCTION<br />
<p>Despite the significant release of NPs, information and knowledge on the fate and transformation of MNPs are still in infancy. Transformed MNPs, in particular CeO<sub>2 </sub>needs to be re-examined since it is considered to be toxic to plants once it is transformed in plant, though CeO<sub>2 </sub>is generally stable<sup>30</sup>. Such concerns also involve detrimental impact on soil microbial community (e.g. application of biosolids on agricultural land as fertilizer and application of MNPs in plant protection products)<sup>31-32</sup> from influencing factors such as release of metal ions and generation of free radicals (CuO)<sup>33-34</sup>, in addition to visible cytotoxicity, oxidative stress, and genotoxicity of CeO<sub>2</sub> NPs<sup>35-36</sup>, showing CeO<sub>2</sub> NPs to be the most toxic among CeO<sub>2</sub>, TiO<sub>2</sub>, and Fe<sub>3</sub>O<sub>4</sub> NPs<sup>37</sup>.</p>
<p>Released NPs into the environment may interact with contaminants, which then affect the fate, transport, and transformation of NPs. Studies indicated that major transformation of NPs occurs in natural systems, interacting with biota thereby NPs become unstable<sup>38-39</sup>. Toxicity of MNPs is found to be related to existing contaminants and the types of MNPs as shown in the studies - decreased soil microbial mass by two model NMPs (TiO<sub>2</sub> and ZnO); significant deposition of Fe<sub>3</sub>O<sub>4</sub> and CuO on soil, leading to low porosity (low hydraulic conductivity)<sup>40-41</sup>.</p>
<p>Such discrepancy in results may be ascribed to various parameters including but not limited to exposure dose and time, the types of microbes, soil organic matter, pH, Eh, ionic strength, and moisture content<sup>40,42-45</sup>. As per influencing factors on the environmental dynamics in fate, transport, and transformation of MNPs, several parameters have been investigated, including the presence of natural organic matter (NOM), salts, other ions, pH, temperature, release of metal ions from dissolution of MNPs. Among them, the presence of NOM was found to influence physicochemical properties of NPs through surface functionalization and modification by increasing, decreasing, or neutralizing electric charge in the presence of salts, Ca<sup>2+</sup> as an example<sup>47</sup>.</p>
<p>Agglomeration showed different toxicity effects, either increase or decrease of the toxicity of microbes as an example, whereas increased dissolution reveals augmented toxicity due to release of metal ions<sup>47-50</sup>. Stability of MNPs can also influence on the fate, toxicity, transformation of MNPs in aqueous media exemplified by amorphous silica (aSiO<sub>2</sub>) coated CeO<sub>2</sub>, which showed reduced toxicity of CeO<sub>2</sub><sup>51</sup>. Joint effects from mixed NPs with surfactants on <em>photobacterium phosphoreum</em> were found to be complex, exhibiting antagonism, additive, and synergistic results from the mixtures with ZnO, NiO, and iron oxide correspondingly<sup>52</sup>.</p>
<p>In fact, many NPs have applied surfactants for modification, thereby often detected in places near NPs manufacturing plants<sup>52-53</sup>. Recent studies revealed that increase of temperature induced aggregation, thereby decreasing dissolution, though the temperature effect was insignificant at higher ionic strength<sup>54</sup>, indicating aggregation was affected by water chemistry than temperature.</p>
<p>The effects of dissolution, which may depend on nanoparticle type, but also concentration, size, coatings, and pH<sup>55</sup>, seems to be the parameter essential in assessing toxicity due to interaction with organisms that could be more toxic than the solid form of NPs. Other than pH, ionic strength, and NOM, other anions (Cl<sup>-</sup>, SO<sub>4</sub><sup>2-</sup>, PO<sub>4</sub><sup>3-</sup>, HCO<sub>3</sub><sup>-</sup>) present in natural water may affect physicochemical characteristic of NPs (aggregation and dissolution) through complexation with metal ions released from NPs. Few studies have investigated the environmental dynamics of NPs under various environmental parameters.</p>
<p>Environmental media as the ultimate sink may also influence the adsorption and accumulation of NPs. Exposure modeling studies showed the significant accumulation of NPs in soils and sediments, while concentration ranges from 10 to 500 (ng/L) of ZnO NPs were detected in surface waters and sewage sludge<sup>56-58</sup>. Physicochemical transformation of NPs under various environmental conditions may be changeable over time and may affect the toxicity of organisms.</p>
<p>Transformation of MNPs occur through chemical transformations (oxidation-reduction processes; ligand exchange; complexation; dissolution), physical reactions such as aggregation / disaggregation and adsorption on organic macromolecules, and biological interactions<sup>59</sup> and would also be influenced by the aforementioned environmental parameters. Subsequently, the transport mechanisms of NPs in the aquatic environment are also not clearly understood, because of different ways of NPs, which are transformed and redistributed through sedimentation<sup>60</sup>. The physicochemical properties of bare or transformed NPs may consequently influence the removal and transport of contaminants attached to the NPs.</p>
<p>While concerns about the potential hazard to the environment and public health have been intensified and more research is encouraged, no studies have been done in looking at how industrial MNPs are different including but not limited to their fate, interaction with contaminants, and transport behavior in comparison to nano-metal oxides embedded in consumer products, especially food. In particular, the interaction between MNPs and contaminants in environmental media needs to be well understood to determine the implications of NPs released into the environment.</p>
<p>Few studies have carried out the effects and potential influence of contaminating MNPs, in particular the impact of contaminants on the fate and transport of MNPs. In this proposed research, particular attention is given to the potential interaction between contaminants and MNPs, looking at their influence on mobilizing MNPs extracted from three model products (classified into edible and non-edible items), alongside the effects of such contaminations on the fate of MNPs from environmental matrices.</p>
<p>The different types of contaminants would undergo transformation in a heterogeneous system that can alter mobility, fate, and toxicity. Very limited studies are available in particular how the coexisting surfactant and NPs behave in complex systems (under various environmental conditions). In this proposed research, types of contaminants to look at are organic molecules that often have been used in various types of consumer products.</p>
<p>Investigating the effects of coexisting contaminants on MNPs, especially the three model MNPs (CeO<sub>2</sub>, TiO<sub>2</sub>, ZnO NPs) will particularly focused in this proposed research. Investigating factors affecting the fate and transport behavior has relatively been new as an initial stage of research. This proposed research will provide <strong><em>transformative knowledge</em></strong> in identifying the interfacial phenomena occurring on MNPs from the physicochemical properties influenced by contaminants and various environmental conditions such as pH, flow rate, types of contaminants, and their concentrations.</p>
<p>Moreover, no information is available on how MNPs in consumer products are different under various environmental conditions, in comparison to industrial MNPs. Overarching questions arising from the potential influence of contaminants on MNPs (both industrial and MNPs extracted from consumer products) include:</p>
<ol>
<li>How are MNPs transformed, and what are their effects on contaminants present under environmental conditions?</li>
<li>What effects could they influence their toxicity to humans and the environment, as well as their mobility?</li>
<li>How do industrial MNPs behave differently in comparison to MNPs from consumer products? Would be their fate and mobility similar or if not, how such discrepancy would affect their fate and transformation upon release into the environment?</li>
<li>Would their toxicity behave in a similar way? if not, what are the possible processes that make such a discrepancy responsible on this?</li>
</ol>
<p>The <em>hypothesis</em> underlying this research effort is that when existing contaminants present in the aquatic environment interact with NPs (e.g., TiO<sub>2</sub>, ZnO, CeO<sub>2</sub> proposed in this research) extracted from the consumer products might result in differences in toxicity, transformation, and retention in environmental media under various influencing factors, compared to the industrial NPs (the three model MNPs chosen in this study).</p>
<p>To address this hypothesis, the research plan proposes three research objectives: (1) investigate the environmental dynamics of MNPs when interacting with existing contaminants; (2) examine the removal and transformation of metal oxides nano-products under various environmental conditions; (3) assess the effect of porous media on the removal and transformation of metal oxides nano-products. This transformative research topic is not only timely, but also critical in assisting manufacturers to design products safely, guiding policy decision-making, and assessing toxicity, since no studies have investigated the transformation of consumer nanoproducts in heterogeneous systems.</p>
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