## 3 Scientometric Analysis: Results and Discussion
### Science Mapping
#### 3.2.1 Mapping of Publication Sources
\begin{table}
\begin{tabular}{c c c c c c} \hline
**A** & **B** & **C** & **D** & **E** & **F** & **G** \\ \hline \multicolumn{6}{c}{Publication count} \\ \hline
1 & _Science of the Total Environment_ & 46 & 1548 & 121.78 & 33.65 & 2.64 \\
2 & _Environ. Sci. Pollut. Res._ & 12 & 86 & 12.78 & 7.17 & 1.06 \\
3 & _Marine Pollution Bulletin_ & 11 & 214 & 24.11 & 19.45 & 2.19 \\
4 & _Sustainability_ (Switzerland) & 9 & 25 & 2.76 & 2.78 & 0.30 \\
5 & _Chemosphere_ & 7 & 118 & 11.73 & 16.86 & 1.67 \\
6 & _Journal of Hazardous Materials_ & 7 & 70 & 19.72 & 10.00 & 2.81 \\
7 & _Resour. Conserv. Recycl._ & 6 & 141 & 9.54 & 23.50 & 1.58 \\
8 & _Chemical Engineering Journal_ & 5 & 375 & 26.44 & 75.00 & 5.28 \\
9 & _Environmental Pollution_ & 5 & 222 & 12.42 & 44.40 & 2.48 \\
10 & _J. Environ. Chem. Eng._ & 5 & 107 & 9.38 & 21.40 & 1.87 \\
11 & _Plos One_ & 5 & 10 & 0.68 & 2.00 & 0.13 \\
12 & _Polymers_ & 5 & 66 & 3.75 & 13.20 & 0.74 \\ \hline \multicolumn{6}{c}{Total citations} \\ \hline
1 & _Science of the Total Environment_ & 46 & 1548 & 121.78 & 33.65 & 2.64 \\
2 & _Chemical Engineering Journal_ & 5 & 375 & 26.43 & 75.00 & 5.28 \\
3 & _Environmental Pollution_ & 5 & 222 & 12.41 & 44.40 & 2.48 \\
4 & _Marine Pollution Bulletin_ & 11 & 214 & 24.11 & 19.45 & 2.19 \\
5 & _Resour. Conserv. Recycl._ & 6 & 141 & 9.53 & 23.50 & 1.58 \\
6 & _Chemosphere_ & 7 & 118 & 11.72 & 16.85 & 1.67 \\
7 & _J. Environ. Chem. Eng._ & 5 & 107 & 9.37 & 21.40 & 1.87 \\
8 & _Environ. Sci. Pollut. Res_ & 12 & 86 & 12.77 & 7.16 & 1.06 \\
9 & _Journal of Hazardous Materials_ & 7 & 70 & 19.72 & 10.00 & 2.81 \\
10 & _Polymers_ & 5 & 66 & 3.74 & 13.20 & 0.74 \\
11 & _Sustainability_ (Switzerland) & 9 & 25 & 2.76 & 2.77 & 0.30 \\
12 & _Plos One_ & 5 & 10 & 0.67 & 2.00 & 0.13 \\ \hline \multicolumn{6}{c}{Average normalized citations} \\ \hline
1 & _Chemical Engineering Journal_ & 5 & 375 & 26.43 & 75.00 & 5.28 \\
2 & _Journal of Hazardous Materials_ & 7 & 70 & 19.72 & 10.00 & 2.81 \\
3 & _Science of the Total Environment_ & 46 & 1548 & 121.78 & 33.65 & 2.64 \\
4 & _Environmental Pollution_ & 5 & 222 & 12.41 & 44.40 & 2.48 \\
5 & _Marine Pollution Bulletin_ & 11 & 214 & 24.11 & 19.45 & 2.19 \\
6 & _J. Environ. Chem. Eng._ & 5 & 107 & 9.37 & 21.40 & 1.87 \\
7 & _Chemosphere_ & 7 & 118 & 11.72 & 16.85 & 1.67 \\
8 & _Resour. Conserv. Recycl._ & 6 & 141 & 9.53 & 23.50 & 1.58 \\
9 & _Environ. Sci. Pollut. Res_ & 12 & 86 & 12.77 & 7.16 & 1.06 \\
10 & _Sustainability_ (Switzerland) & 9 & 25 & 2.76 & 2.77 & 0.30 \\
12 & _Plos One_ & 5 & 10 & 0.67 & 2.00 & 0.13 \\ \hline \end{tabular} (A) Position in rankings; (B) name of journal; (C) total number of documents published in the field; (D) total citations of documents published in the field; (E) normal citations: citation of all documents within same journal; (F) average citations: total citations per document in journal; (G) average normal citations: normalized number of citations of journal, which is equal to the total number of citations divided by the average number of citations published in the same year.  
\end{table} 
Table 1: Ranking of journals with more importance in the field in terms of total publication count, total citations, and average normalized citations. Finally, Figure 4 provides a network visualization of the sources containing the 12 sources included in the ranking in terms of the number of documents. All of them are connected, and the size of a cluster indicates the contribution of that source to the publication count; a larger size implies greater influence. In this way, because _Science of the Total Environment_ has larger circles compared with the other journals, this means that this journal has the highest impact on the research field in terms of the number of papers. Additionally, circles with the same color indicate the clusters of sources associated in terms of the scope of research outlets or the number of times they are co-cited [37].