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Open AccessReviewPost Publication Peer ReviewVersion 1, Original

Endocrine Disrupting Compounds Removal Methods from Wastewater in the United Kingdom: A Review (Version 1, Original)

1
Polystar Plastics Ltd., Southampton SO14 5RB, UK
2
Department of Architecture and the Built Environment, University of the West of England, Bristol BS16 1QY, UK
3
The Swansea Business School, University of Wales Trinity Saint David, Swansea, High St, SA1 1NEK, UK
4
Warsash School of Maritime Science and Engineering, Solent University, Southampton SO14 OYN, UK
*
Author to whom correspondence should be addressed.
Received: 29 January 2019 / Accepted: 19 February 2019 / Published: 21 March 2019
Peer review status: 1st round review Read review reports

Reviewer 1 Edmond Sanganyado Shantou University Reviewer 2 Sumit Sinha Ray 1. Assistant Professor School of Engineering Indian Institute of Technology Mandi and 2. Adjunct Assistant Professor Department of Mechanical and Industrial Engineering University of Illinois at Chicago
Version 1
Original
Approved with revisions Approved with revisions
Endocrine disrupting compounds (EDCs) are contaminants with estrogenic or androgenic activity that negatively impact human and animal communities. These compounds have become one of the significant concerns for wastewater treatment in recent decades. Several studies have evaluated EDC removal methods from wastewater across the globe including the United Kingdom (UK). Accordingly, the current study reviews EDC removal methods from municipal/domestic wastewater in the United Kingdom (UK) for the period of 2010–2017. The research highlights that despite the relative efficacy of existing chemical and physical methods for removing certain EDCs from wastewater there is emerging evidence supporting the need for more widespread application of nature-based and biological approaches, particularly the use of biofilms. The analysis reveals that there have been relatively few research studies on EDC removal methods have been carried out in the UK in the 2010–2017 period and none of the research focused on EDC removal using biofilms. Finally, this review suggests that more research is needed to remove EDCs, particularly through the application of biofilms, from municipal wastewater in current scenarios.
Keywords: wastewater treatment; temperatures; systematic review; biofilms; endocrine disrupting compounds wastewater treatment; temperatures; systematic review; biofilms; endocrine disrupting compounds
MDPI and ACS Style

Gadupudi, C.K., 1; Rice, L., 1; Xiao, L., 1; Kantamaneni, K., 1; Endocrine Disrupting Compounds Removal Methods from Wastewater in the United Kingdom: A Review. Sci 2019, 1, 15.

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1

Reviewer 1

Sent on 27 Mar 2019 by Edmond Sanganyado | Approved with revisions
Shantou University

In this review, the authors evaluated recent progress and provided their perspectives on the removal of endocrine disrupting compounds in wastewater systems. Considering the potential human and environmental health risks posed by EDCs, understanding the removal pathways and mechanisms of EDCs is imperative. Importantly, the evaluation of the recently developed EDC removal methods is crucial for the development of EDC pollution mitigation strategies. However, the current review did not adequately evaluate the state of science in EDC removal technology due to the limitations of the methodology. The authors may want to look at the different types of EDCs and their physicochemical properties as well as implications of these properties on removal efficiencies in various technologies.


Abstract


The authors state that EDCs negatively impact humans and animals. However, EDCs are a broad heterogeneous group with a wide spectrum of toxicity; therefore, the authors may want to remove absolutes in this statement.


The authors may want to state their principal findings following the literature search – for example, what were the most commonly used EDC removal techniques, what was the EDC removal efficiency, what were the key EDCs investigated in most studies?


Introduction


The first paragraph is disjointed and has some repetitions (e.g. 2nd sentence is a repetition of the 3rd sentence, the last four sentences are redundant). The authors should probably state why the occurrence of EDCs in aquatic systems is of concern, highlight the reported human and environmental toxicities, and briefly state the different types of EDCs and their sources.


The classification of EDCs given by the authors seems to be inaccurate. Specifically, what is the difference between synthetic estrogens and xenoestrogens or natural estrogens and phytoestrogens? Xenoestrogens are synthetic chemicals and phytoestrogens are natural chemicals. Furthermore, the claim that natural and synthetic estrogens have greater estrogenic effects than phyto- and xenoestrogens is semantically inaccurate considering there are the same.


The authors may want to provide experimental evidence on the occurrence of EDCs in aquatic systems in the UK. A table with columns on environmental matrices, EDC contaminants, detected concentrations, and comments on the results of the different studies the authors found in the UK could be expedient.


The authors may want to address EDC removal efficiency in conventional wastewater treatment plants so that the need for the development of new techniques can become clear.


Endocrine Disrupting Compounds and Their Impacts


The statement that most EDCs have not been studied is speculative. A search on EDCs on SCOPUS yields more than 13,000 results for compounds ranging from legacy EDCs such as DDTs and emerging contaminants such as phthalates. There numerous analytical techniques that have been developed for trace analysis of EDCs in environmental samples.


The last paragraph in this section is hard to follow. The authors first suggest that Synder et al. (2003) found estrogenic compounds in drinking water were not responsible for adverse effects in humans. The authors suggested that Synder et al. (2003) focused on fish, thus the results could not be extrapolated to humans. However, Snyder et al. (2003) did not conduct a mechanistic study on the estrogenic activity of EDCs in humans but focused on EDC analysis, occurrence, and removal. The authors then suggested that numerous studies have been conducted on EDC toxicity that found them potentially toxic. However, considering that most studies focused on non-human exposure, why were these results acceptable and ‘those’ by Synder et al. rebuffed?


The distinctive biological properties of EDCs may not have an influence on their removal efficiencies in STPs. Importantly, since EDCs are a diverse group of compounds, one would expect their removal efficiencies in STPs to be widely varied as well.


The last sentence of this section requires clarification because sewage treatment plants are a type of wastewater treatment plant. Therefore, saying wastewater treatment plants are efficient at removing EDCs is probably inaccurate.


Wastewater Treatments and EDCs Removal Procedures


The first paragraph is disjointed it focuses on the toxicity of EDCs something that has already been covered in previous passages and EDC removal techniques. The authors should just focus on the removal techniques and give more details on the pros and cons of different techniques, using results from previous studies. As stands, the passage is too skeletal and requires more specific examples with explanations.


The authors may want to discuss the different physicochemical properties of the EDCs that influence their removal. They should state exactly what “cutting-edge research” that found EDCS commonly detected are susceptible to dissolution. After all, from the chemical structure of EDCs and various previous studies, EDCs often readily adsorb to particulate matter and are commonly found in sediments. Furthermore, being readily soluble is a product of the polarity of the compound, and EDCs are a diverse group that ranges from polar to less polar compounds.


Furthermore, the authors should provide primary evidence on what the mean by “little reduction” for less polar EDCs.


Methodology


The authors used ScienceDirect for their literature search and this limited their search to Elsevier publications. Using SCOPUS or Web of Science could have provided a broader scope for the study. Secondly, the authors may want to include the exact search string they used for the searches. It is probably helpful if the authors can state how they identified studies from the UK in their search. Furthermore, some studies on removal of EDCs do not state within the text that the compound investigated is an EDC, a common example is DDTs. What did the authors do to ensure that these studies were included in their literature search? This is particularly important because the conclusion drawn from the review that they are few studies on EDCs in UK could be due to the bias of the methodology.


Results and Discussion


The authors should critically evaluate the 4 publications they found (It is important to note that this low number of publications is probably a reflection of the weakness of the methodology). What were the key removal techniques investigated, what were the removal efficiencies, what were the EDCs investigated, etc.?

 

 


Reviewer 2

Sent on 28 Aug 2019 by Sumit Sinha Ray | Approved with revisions
1. Assistant Professor School of Engineering Indian Institute of Technology Mandi and 2. Adjunct Assistant Professor Department of Mechanical and Industrial Engineering University of Illinois at Chicago

Authors of this article have tried to assemble the present methods to decontaminate water from EDC elements, particularly for UK in the period of 2010-17. EDCc are problems to drinking water or discharging water and hence a comprehensive review of such domain is important. However, some issues with the article needs to be addressed -

Abstract and results/discussion section don't seem to fit to each other as I couldn't see any such detail on biofilm, as mentioned in former section. Can authors shed some light on biomagnification on the context of "However, exposure to EDCs for humans is distinct from
aquatic organisms such as fish, therefore, an equivalent hormonal response might not be anticipated". Table 3 is poorly described, with no real data/reference of certain process's inefficiency. "The current review presents endocrine disrupters removal methods which were established for the period of 2010–2017 from wastewater in the United Kingdom"- This statement is vague, because only two articles are described. Can authors describe, how activated carbon adsorption is cos-ineffective than the two mentioned in their article?
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