# An Exploratory Review of Microplastic Pollution, Associated Microbiomes and Pathogens in Water
## 3 Results and Discussion
### Microplastics in Surface Waters
The analysis of the MP level due to the type of water reservoir showed that the highest level was found in water from lakes, with an average level of 946 particles/m\({}^{3}\), compared to rivers or coastal regions (457 and 368 particles/m\({}^{3}\), respectively) (Table 5, Supplementary File S5--Africa and Australia). As in other regions, the observed discrepancy between average and median values may reflect the influence of isolated hotspots with elevated MP levels, particularly in heavily polluted inland waterbodies. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Type** & **Amount of MPS (Particles/m\({}^{3}\))** & **References** \\ \hline \multirow{3}{*}{River} & Median & 150.00 & \\ \cline{2-4}  & Average & 1284.42 & \\ \cline{2-4}  & SD & 5281.52 & \\ \hline \multirow{3}{*}{Lakes} & Median & 1.4 & \\ \cline{2-4}  & Average & 37.78 & \\ \cline{2-4}  & SD & 58.08 & \\ \hline \multirow{3}{*}{Sea/bay} & Median & 0.47 & \\ \cline{2-4}  & Average & 0.48 & \\ \cline{1-1} \cline{2-4}  & SD & 0.17 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The average level of MPs in South America depends on water type (particles/m\({}^{3}\)). Figure 4: Sampling sites for detection of MPs—South America. **Australia:** In the case of Australia, the smallest number of papers was evaluated (n = 3, Figure 6). In the analyzed studies, the highest MP level was found in northern central Victoria in the ponds holding shrimps, with this ranging from 170 to 720 particles/m\({}^{3}\), and in the Goulburn River, with the level ranging from \(\sim\)110 to 650 particles/m\({}^{3}\)[54]. In turn, the lowest level was found in the Rib reef area, at 0.02 particles/m\({}^{3}\)[55]. In the other analyzed places, the MP level did not exceed 2 particles/m\({}^{3}\) (Supplementary File S5--Africa and Australia). The comparison of MP levels depending on the water body type showed that the highest level was found in the surface water of rivers and lakes. On the other hand, the levels were the lowest in coastal regions, where the average was estimated to be \(\sim\)0.08 particles/m\({}^{3}\) (Table 6, Supplementary File S5--Africa and Australia). As observed in other regions, the discrepancy between the average and median values may result from high outlier concentrations in specific locations (e.g., aquaculture zones), skewing the overall dataset. Figure 5: Sampling sites for detection of MPs—Africa. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Type**} & \multicolumn{2}{c}{**Number of MPs (Particles/m\({}^{3}\))**} & \multicolumn{1}{c}{**References**} \\ \hline \multirow{3}{*}{River} & Median & 457.50 & \\ \cline{2-4}  & Average & 457.50 & \\ \cline{2-4}  & SD & 247.50 & \\ \hline \multirow{3}{*}{Lakes} & Median & 2.19 & \\ \cline{2-4}  & Average & 946.00 & \\ \cline{2-4}  & SD & 2549.09 & \\ \hline \multirow{3}{*}{Sea/bay} & Median & 129.53 & \\ \cline{2-4}  & Average & 368.66 & \\ \cline{1-1} \cline{2-4}  & SD & 499.78 & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The average level of MPs in Africa depends on water type (particles/m\({}^{3}\)). Taken together, the reviewed data reveal substantial regional differences in microplastic concentrations, shaped by local anthropogenic pressures, waterbody types, and research intensity. It should be noted that current knowledge is heavily skewed toward studies from Asia and Europe, while surface waters in South America, Africa, and Australia remain largely understudied. This geographical imbalance limits the global generalizability of conclusions and underscores the urgent need for standardized, large-scale monitoring programs in underrepresented regions to provide a more comprehensive understanding of microplastic pollution patterns worldwide.