Introduction
Water is an important natural resource of all over the world. We live without food for few days but not without water. It is need for the survival of all organisms including human, food production and economic development. Two thirds of the earth surface is covered by water. Water is life for all but this water is polluting day by day in severe condition and our life is not safe now. We are living in crisis period. Water pollution is a major serious problem for all over the world and its affects drinking water, rivers, lakes and oceans all over the world. It consequently harms the health and wellbeing of human life and the natural environment.
Polluted water not only affects the life of present generation but it also affect the life of upcoming generations because its effect remains for long. If water is polluted in an area, then the all living creatures and people are faced to drink polluted water because they have no other option. It affects their bodies, skin, lungs, brain, liver and kidneys, caused cancers, birth defects and other diseases.1 This is clear from the scientometric evidence from 2012 to 2021, that the number of publications in the Web of Science database was increased from 2302 to 8079. Therefore the present study has been undertaken to know the growth and development of publications in the field of water pollution.
Review of Literature
Sivasami analysed to year wise publications, authorship pattern, sources wise publications, top twenty institutions, top twenty countries contributed on water pollution research.2 The data was collected from the Scopus database from 2006 to 2020. The study found that, articles are highly contributed with 69.75 percent publications, sources type wise research publications on water pollution. Journal has contributed 77.38 percent papers, out of 4152 water pollution publications; first and second place occupies Chinese institutions. Saraswathy Kasavan conducted to explore research trends regarding plastic pollution in the water ecosystem.3 Data of publications output was identified based on the Web of Science (WoS) database's research articles from 2000 to 2020. This study used VOSviewer to analyse collaboration networks among authors, countries, institutions, and co-occurrence analysis of keywords in three defined periods. A total of 2182 papers in plastic pollution in water ecosystem research were identified.
Wang, Ming-Huang presented a detailed chronological survey of papers published in the journal titled Water Research which started publication since 1967. This current investigation reviews publication patterns between 1967 and 2008. An analysis of the research performance according to publication output, distribution of words in article title, author keywords, and keywords plus. Performances of countries, institutes, and authors, including total, single, collaborative, first author, and corresponding author publications were analyzed. Wang et al.,4 identified certain characteristics of literature related to river water quality assessment and simulation and consequently to assist researchers to establish future research directions. There were 3701 articles pertinent to river assessment and simulation published by SCIE and SSCI databases from 2000 to 2014. Various publication characteristics were analyzed, such as countries, research organizations, subject categories, journals and keywords.
Enos wambu and Yuh-Shan Ho analysed a total of 1917 publications of drinking water research in Africa from 1991 to 2013 were identified from the data hosted in Web of Science, for bibliometric analysis.5 The analysis included publication output, distribution of keywords, journals and subject areas, and performances of countries, institutions, and authors. Citation trends and highly-cited publications are also reported. Yaxing Zhou et al.6, 7, Analyzed the related papers on karst groundwater pollution in the core database of Web of Science, intending to sort out the research results in this field and explore potential research hotspots. Analysis results show that, In recent years, the number of publications and citations in this field has gradually increased, and there is a large space for research and development; The United States, China, Germany are the countries that have contributed the most in this field.
Objectives for the Study
The present study has been undertaken with the objectives of analysing the following aspects:
Materials and Methods
The Web of Science database was used for retrieving data on water pollution in topic field. A total of 44172 publications were downloaded and analysed by using the Microsoft excels per the objectives of the study. The Web of Science database allows us to refine the results in terms of publication years, countries, institutes, authors, language, subjects and source titles.
Data analysis and Interpretations
Growth of publications
A total of 44172 water pollution publications were published during 2012-2021. The highest number of publications was 8079 (18.29%) published in 2021. The lowest publications 2302 (5.21%) were published in 2012. The average number of publications published per year was 4417.2. But it is seen that first five years in which the less than average papers (2913.4) were published i.e. 2012-2016. The more productive years with more than average papers were in 2017-2021. It is also found out that an increasing trend in quantum of publications during the study period.
Relative growth rate (RGR and doubling time
The Relative Growth Rate (RGR) is the increase in number of articles or pages per unit of time. The mean relative growth rate (R) over the specific period of interval can be calculated from the following equation.
Relative Growth Rate (RGR)
1 - 2R=Log W2 – Log W1/ T2-T1
Doubling Time (DT) = 0.693/R
Table 1
Relative growth rate (RGR) and doubling time (DT) of publications
The year wise RGR is found to be in the range of 0.74 to 0.22. It has been observed from Table 1 and Figure 1 that RGR is downward trend from 2013 (0.74) to 2018 (0.22).
The Doubling Time (DT) has increased when calculated year wise. The Doubling Time increases from 0.94 in 2013 to 3.15 in 2018. In 2019 to 2021, the values are constant. Though the doubling time is increasing but it is not showing the exponential growth rate as seen in the annual growth rate analysis presented in the table.
Trend analysis –Method of least squares
This is the best method for obtaining the trend values. It provides a convenient basis for obtaining the line of best fit in a series.
Where, Y represents the estimated values of the trend, X represents the deviations in time period; ‘a’ and ‘b’ are constants.
Σ Y = Na + bΣ X
XY = a Σ X + bΣ X2
Table 2
Computation of straight line trend by the least squares method
The equation of the straight line trend is Y= a + bX
Since ∑ X=0, therefore
∑ X 44172
a= ------ = -------- = 4417.2
N 10
∑ XY 170492
b= ------ = ---------- = 378.87
∑ X2 450 Thus, substituting the value of ‘a’ and ‘b’ in the straight line of the trend, we get
Y= a + bX
Estimate of 2031 will be calculated on the basis of X= 31
Y2031 = 4417.2 + (378.87) x 31 = 16162
With the use of the trend analysis, the trend values are calculated up to 2031. The trend line and actual line are presented in the Figure 4. And, it is seen from the Table 2, that the actual trend was standard in the year 2012 since then there is an upward trend up to the year of 2021. The trend value has been increased from 1007 in 2012 to 16162 in 2031. It is interesting to note that there is an upward trend in the growth of the literature. From this it can be interpreted that the upward trend in the actual line reflects in the trend line also.
Table 3
Language wise distribution of publications
Language wise distributions
Publications on water pollution are spread over 13 languages. The study reveals that the maximum number of publications have been published in English language with 44018 (99.65%) publications, followed by Chinese with 44 (0.10%) publications, Spanish ranks third position with 30 (0.07%) publications, French with 30 (0.39%) publications, French with 19 (0.04%) publications and German with 18 (0.04%) publications. The most predominant language used for communication was English in every year in total productivity on the subject during the study period.
Highly productive countries
In all, there were 191 countries involved in the research in water pollution field and which published at least one publication. The publications share of highly productive countries (≥1400 publications) in water pollution varies from 3.25% to 36.08r% as seen in the Table 4 and Figure 4. China topped the list with highest share 15938 (36.08%) of publications. USA ranked second with 6385 (14.45%) share of publications followed by India with 2712 (6.14%) share of publications, Spain with 1926 (4.36%) share of publications, England with 1870 (4.23%) share of publications, Germany with 1849 (4.19%) share of publications and the remaining countries are publishing less than 4% of the research output in this study period.
Table 6
Authorship pattern
Table 7
Highly productive institutes
Table 8
Sourcetitle of publications
Table 9
High productivity subject areas
Most prolific authors
The authors having 200 or more publications during 2012-2021 are given in Table 5. Zhang Y is the most productive author with 412 (0.93%) publications followed by Liu Y with 353 (0.80%) publications, Wang Y with 348 (0.79%) publications, Li Y with 329 (0.74%) publications, Li J with 319 (0.72) publications, Wang J with 298 (0.67%) publications, Zhang, J with 248 (0.56%) publications and Zhang L with 247 (0.56%) publications respectively. And a total of 1, 00,025 authors are contributed entire research output of the period under study.4
Authorship pattern
Authorship trend the whole publications were divided into the four categories (single, double, multi and mega-authored) are presented in table 6. Out of 44172 water pollution publications, 2383 (5.39%) were single authored papers, 7258 (16.43%) two authored papers, 17910 (40.55%) multi-authored papers and 16621 (37.63%) mega-authored papers. The authorship pattern clearly shows that 78.18% publications were contributed by multi and mega-authors while 21.82% of total publications were published by single and double-authors.
As per Degree of Collaboration of a discipline, must be between 0 and 1, hence the degree of collaboration of total publications of the water pollution is 0.94. The value of degree of collaboration brings out clearly the prevalence of team research in water pollution field. Out of the total publications, 94.61 % publications were collaborated by multi authors and 5.39 % of total contributions by single authors.
Analysis from the Table 6, Collaboration Index varies from 1.63 in 2021 and highest collaboration notices in 2013 i.e. 2.98. The average collaboration index is 2.42.
Highly productive institutes
Resents the top 10 institutes that have contributed 350 or more publications on water pollution during 2006-2015. A total of 23,519 institutions are contributed entire research output of the study. Chinese Academic of Sciences, China topped the list with 3013 (6.82%) publications followed by University of Chinese Academic of Sciences, China with 1116 (2.53%) publications, Beijing Normal University, China with 718 (1.63%) publications, Tsinghua University, China with 533 (1.21%) publications, Chinese Research Academy of Environmental Science, China with 440 (1.00%) publications and Nanjing University, China with 420 (0.952%) publications. It is interesting to note that the all top ten institutions are from China.
Most preferred source titles
Rovides the leading journals each with number of publications and impact factor. The scientific literature onwater pollution is spread over 2728 different web of science source journals. It reveals that Science of the Total Environment the list with the highest number of publications 2677 (6.06%) and the impact factor is 10.75, followed by Environmental Science and Pollution Research with a share of 2043 (4.62%) publications and the impact factor is 5.19. Marine Pollution Bulletin occupies the third position with 1148 (2.60%) publications and the impact factor is 5.553. The fourth highest source title is Environmental Pollution with 1098 (2.49%) publications and the impact factor is 8.071, Environmental Monitoring and Assessment with 1083 (2.45%) publications and the impact factor is 2.513 and Water with 982 (2.22%) publications and the impact factor is 3.530.
High productivity subject areas
The scientific literature on water pollution is spread over 93 different subjects.Table 9 shows high productivity subjects which are contributing more than 300 articles. It is found that Environmental sciences ecology has highest number of articles with 24562 (55.60%) followed by Engineering contributing 8911 (20.17%) articles. Energy fuels occupy the third position with 3873 (8.77%) articles. The fourth highest articles belonged to the subject Physical sciences with 3495 (7.91%) articles, Chemistry with 2931 (6.63%) articles and Marine freshwater biology with 2900 (6.56%) articles respectively.
Conclusions
The present study attempted to highlight the growth and development of research publication on water pollution. A total of 44172 publications were published during 2012-2021 and the average number of publication per year was 4417.2. The exponential growth of publication was observed during the study period. Publications on water pollution are spread over 13 languages. Zhang Y is the most productive author with 412 (0.93%) publications followed by Liu Y with 353 (0.80%) publications and Wang Y with 348 (0.79%) publications and a total of 1,00,025 authors are contributed entire research output of the period under study. Degree of collaboration for total publications of the water pollution was 0.94. The value of degree of collaboration brings out clearly the prevalence of team research in water pollution which is evident, out of total publications, 94.61% were collaborated with multi authorship and 5.39% by single authors. The scientific literature on water pollution is spread over 2728 different web of science source titles.
Article DOI
