## 3 Results and Discussion  
### Laboratory Analysis of the Sampled Sedimented Material  
Through samples of sedimentary material collected at 12 specific points in Cartagena Bay, in the regions of Bocagrande, Isla Tierra Bomba, and Playa Blanca, it was possible to determine quantitatively the chemical elements present in 1343 identified NPs and ultrafine particles. In this context, the quantitative identification of chemical elements in NPs becomes of fundamental importance so that governments and public managers can define future policies aimed at preserving hydrological sources and mitigating preserve hydrological sources and mitigate the number of chemical elements that generate large-scale water pollution [1; 36; 49].  
The studied regions of Bocagrande, Isla Tierra Bomba, and Playa Blanca in Cartagena Bay present chemical elements harmful to human health and the aquatic environment associated with the NPs in the analyzed material. The XRD results demonstrated that quartz and kaolinite are the most abundant found in the samples collected in this study (Figure 3). In the areas of Bocagrande and Isla Tierra Bomba, a high degree of plastic particles was identified, which are related to carbon nanotubes with characteristics of fullerenes (Figure 4). According to [PERSON] et al. [50], fullerenes consist of spheroidal-shaped nanomolecules capable of incorporating carbon atoms into their structure. On the other hand, in the Playa Blanca region, the sampled material did not reveal chemical contaminants at high levels.  
Based on electron microscopy results, the presence of multiple fibers associated with plastics and chemical elements was verified. During the HR-TEM analysis, when a vacuum  
Figure 3: The XRD results demonstrate quartz and kaolinite as the most abundant elements.  
was applied, the displacement of agglomerated chemical elements was observed without identifying the fibers' absorption capacity of these elements (Figure 4).  
In Figure 5, the presence of significant elements can be observed. Aluminum (Al), iron (Fe), magnesium (Mg), and sodium (Na), among others, were found deposited as nanominerals (Table 1). The use of FIB-SEM in this study is justified by the ability to cut agglomerates with large sizes, which allows for an understanding of their internal structures. This allowed the detection of minerals present in the analyzed structures and the identification of their amorphous phases in microstructures. According to [PERSON] et al. [51] and [PERSON] et al. [52], identifying chemical elements in structures smaller than 10 \(\upmu\)m is innovative, as it allows for better quantitative identification in structures such as NP nanoparticles and ultrafine particles.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Identified Mineral** & **Bocagrande Neighborhood** & **Isla Tierra Bomba** & **Playa Blanca** \\ \hline Anatase & x & x & x \\ Anhydrite & - & - & x \\ Bararite & x & x & x \\ Barite & x & x & x \\ Calcite & x & x & x \\ Chromite & - & x & x \\ Chlorite & x & x & x \\ Goethite & x & x & x \\ Halite & x & x & x \\ Hematite & x & x & x \\ Illite & x & x & x \\ Kaolinite & x & x & x \\ Metakaolinite & x & x & x \\ Monazite & x & - & x \\ Quartz & x & x & x \\ Rutile & x & x & x \\ Siderite & - & x & - \\ Gypsum & x & x & x \\ Pyrite & - & x & x \\ Fullerene & x & x & x \\ Amorphous & x & x & x \\ \hline \hline \end{tabular}
\end{table}
Table 1: Deposition of nanominerals identified in samples collected (x = presence of substance) from the Bocagrande neighborhood, Isla Tierra Bomba, and Playa Blanca in Cartagena Bay.  
Figure 4: Scanning electronic microstructure of pollution samples collected in the regions of the Bocagrande neighborhood and Isla Tierra Bomba in Cartagena Bay.