# An Exploratory Review of Microplastic Pollution, Associated Microbiomes and Pathogens in Water
## 3 Results and Discussion
### Microplastics in Surface Waters
In this case, the lowest level occurred in the Holland River, with \(\sim\)0.1 particles/m\({}^{3}\), while the highest occurred in lake Winnipeg and on the west coast of Vancouver Island (\(\sim\)1933 and \(\sim\)2000 particles/m\({}^{3}\), respectively) [47; 48; 49; 50]. When analyzing the MPS level according to the waterbody type (Table 3), the results showed that in rivers in Canada, the average level of MPS was about \(\sim\)132 particles/m\({}^{3}\) in lakes, at -5 particles/m\({}^{3}\), and in the sea/bays, at -715 particles/m\({}^{3}\) (Supplementary File S3--North America). \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Type** & **Amount of MPS (Particles/m\({}^{3}\))** & **References** \\ \hline \multirow{3}{*}{River} & Median & 392.9 \\ \cline{2-3}  & Average & 8166.39 \\ \cline{2-3}  & SD & 7758.07 \\ \hline \multirow{3}{*}{Lakes} & Median & 5.00 \\ \cline{2-3}  & Average & 14,974.97 \\ \cline{2-3}  & SD & 14,226.22 \\ \hline \multirow{3}{*}{Sea/bay} & Median & 710.00 \\ \cline{2-3}  & Average & 24,372.06 \\ \cline{1-1} \cline{2-3}  & SD & 23,153.45 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The average level of MPs in Europe depends on water type (particles/m\({}^{3}\)). Figure 2: Sampling sites for detection of MPs—Europe. On the other hand, when comparing the level between Canada and the USA, a higher level occurred in the USA than in Canada (Supplementary File S3--North America). As in previous regions, the noticeable difference between the mean and median values is likely driven by a few exceptionally high concentrations recorded in specific coastal or estuarine sites, causing a skewed distribution of MP levels. **South America**: In the case of South America, publications were selected mainly from the areas of Argentina, Ecuador, Paraguay and Colombia (n = 8, Figure 4), where the highest levels were found in The Bahia Blanca estuary (Argentina) in the medium range from about 596 to 30,893 particles/m\({}^{3}\). In turn, the lowest levels were found in the Tropical Eastern Pacific and Galapagos, where the level did not exceed 1 particles/m\({}^{3}\)[5; 51]. In the remaining areas, the level ranged from approximately \(\sim\)0.4 to 3700 particles/m\({}^{3}\); however, most of the values did not exceed 200 particles/m\({}^{3}\) (Supplementary File S4--South America). The highest level, in terms of the waterbody type, was typical for rivers, with an average of \(\sim\)1278 particles/m\({}^{3}\); the lowest levels were in sea/coastal regions, with an average of 0.48 (Table 4, Supplementary File S4--South America). The discrepancy between the mean and median values in South American waters likely results from a few extreme values, especially in estuarine sites like Bahia Blanca, which strongly influence the average and skew the overall distribution. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Type**} & \multicolumn{2}{c}{**Amount of MPS (Particles/m\({}^{3}\))**} & \multicolumn{1}{c}{**References**} \\ \hline \multirow{3}{*}{River} & Median & 392.9 & \\ \cline{2-4}  & Average & 8166.39 & \\ \cline{2-4}  & SD & 7758.07 & \\ \hline \multirow{3}{*}{Lakes} & Median & 5.00 & \\ \cline{2-4}  & Average & 14,974.97 & \\ \cline{2-4}  & SD & 14,226.22 & \\ \hline \multirow{3}{*}{Sea/bay} & Median & 710.00 & \\ \cline{2-4}  & Average & 24,372.06 & \\ \cline{1-1} \cline{2-4}  & SD & 23,153.45 & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The average level of MPs in North America depends on water type (particles/m\({}^{3}\)). Figure 3: Sampling sites for detection of MPs—North America. **Africa:** In the case of Africa (Figure 5), 12 publications were analyzed; these showed the lowest MPs level in the surface water of Lake Victoria, at \(\sim\)0.14 particles/m\({}^{3}\)[52], and the highest level in Lake Yenagoa, where the detected concentrations ranged from about 201 to 8369 particles/m\({}^{3}\)[53]. In turn, the average MP level in the analyzed publications was about 814 particles/m\({}^{3}\) (Supplementary File S5--Africa and Australia).