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Peer-Review Record

Effects of Chlorpyrifos Ethyl on Cholinesterase and Growth of Silver Barb (Barbonymus gonionotus)

Water 2021, 13(20), 2885;
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Water 2021, 13(20), 2885;
Received: 30 September 2021 / Revised: 6 October 2021 / Accepted: 11 October 2021 / Published: 14 October 2021
(This article belongs to the Section Water, Agriculture and Aquaculture)

Round 1

Reviewer 1 Report


Paper title: Effects of Chlorpyrifos Ethyl on Cholinesterase and Growth of Silver Barb (Barbonymus gonionotus).


The authors conducted an experimental study to reveal the effects of Chlorpyrifos Ethyl, a widely used pesticide, on the physiology and growth rates of Silver Barb fingerlings in Vietnam. The authors found that chlorpyrifos ethyl is highly toxic to this species with the LC 50–96h of 0.119 ppm. They suggest that the fish cholinesterase activity may be inhibited significantly when exposed to actual concentrations of the pesticide in the water used in agriculture. This information has important implications for aquaculture and water management in the study area.


All these reasons explain the relevance of the paper by Nguyen Van Cong and co-authors submitted to "Water".


General scores.


The data presented by the authors are original and significant. The study is correctly designed and the authors used appropriate methods. In general, the statistical analyses are performed with good technical standards. We authors conducted careful work which may attract the attention of a wide range of specialists focused on aquatic toxicology and fish biology.


Specific comments.


L 8. Change “within” to “within the”

L 9. Change “in the often” to “often”

L 12. Change “system” to “systems”

L 12. Change “Resultantly, the” to “As a result, this”

L 15. Change “on Silver barb” to “of Silver barb”

L 15. Change “static” to “a static”

L 17. Change “brain ChE of fingerling fish for 15 days, and on growth for 60 days” to “on the brain сcholinesterase (ChE) of fingerling fish for 15 days, and on their growth for 60 days”

L 18. Change “showed” to “showed that”

L 21. Change “are significantly” to “is significantly”

L 22. Change “environmental” to “environmentally”

L 22. Change “biomarker” to “a biomarker”

L 24. Change “should be investigated” to “is required.”

L 30. Change “since” to “over”

L 32. Change “of pesticide” to “pesticide”

L 33. Change “hectare are” to “hectare”

L 36. Change “pesticide” to “pesticides”

L 37. Change “most common” to “most commonly”

L 38. Change “The water concentration of this insecticide” to “The concentration of this insecticide in water”

L 40. Change “environment but it is high toxic” to “the environment but is highly toxic”

L 47. Change “ChE inhibition” to “сcholinesterase (Che) inhibition”

L 49. Change “water breathing” to “water-breathing”

L 51. Change “environmental” to “environmentally”

L 52. Change “ethyl to” to “ethyl on”

L 56. Change “3-5g/fish” to “weight 3-5g”

L 58. Change “acclimatized” to “acclimatized in”

L 58. Change “condition” to “conditions”

L 63. Change “which could” to “that could”

L 76. Change “experiment” to “experimental”

L 79. Change “minimized” to “minimize”

L 79. Change “noted” to “recorded”

L 86. Change “During” to “During the”

L 87. Change “commence” to “commences”

L 93. Change “2.3.2. Effect” to “2.3.3. Effect”

L 93. Change “on growth” to “on the growth”

L 105. Change “during” to “during the”

L 106. Change “The environment was run for 60 days.” to “The experiment lasted for 60 days.”

L 108. Change “2.3.3. Calculation” to “2.3.4. Calculation”

L 123. Change “Survival rate” to “Survival rate was determined as follows”

L 126. Change “2.3.4. Data analysis” to “2.3.5. Data analysis”

L 129. Change “one-way analysis of variance” to “a one-way analysis of variance”

L 130. Change “Significant difference was considered as” to “Significant differences were considered at”

L 133. Change “experiement” to “experimental”

L 133. Change “were found to vary” to “varied”

L 136. Change “significant  difference” to “significantly  different”

L 139. Change “Data was presented mean±SD” to “Data are presented as means±SD”

L 152. Change “This is before, airbreathing” to “This value is lower than in air-breathing”

L 153. Change “can” to “which can”

L 158. Change “means” to “mean values”

L 161. Change “Data was presented mean±SD” to “Data are presented as means±SD”

L 162. Change “trends” to “the levels”

L 165. Change “was found fully recovered at one-week post exposure” to “was found to be fully recovered at one week post-exposure”

L 168. Change “different to” to “different from”

L 172. Change “although at” to “despite”

L 173. Change “the maximum” to “and the maximum”

L 182. Change “ability” to “ability to”

L 183. Change “the natural” to “natural”

L 188. Change “right” to “immediately”

L 189. Change “actual” to “the actual”

L 194-196. the sentence “The environmental conditions of the experiment…” should be moved to “Effect of sub-acute concentrations of chlorpyrifos ethyl on growth of Silver barb” (this information partially occur in this section, please, update)

L 196. Change “mean environmental condition” to “environmental conditions”

L 202. Change “increased  relatively” to “increased”

L 205. Change “different to” to “different from”

L 206. Change “pesticide contaminated” to “pesticide-contaminated”

L 207. Change “increaseing” to “increased”

L 210. Change “intake was relatively” to “intake”

L 212. Change “increased” to “higher”

L 217. Change “presented mean ±SD” to “presented as means ±SD”

L 220. Change “were seen” to “was seen”

L 221. Change “inhibitions  was” to “inhibitions  were”

L 223. Change “Water concentrations” to “The concentrations”

L 223. Change “was reported” to “were reported”

L 225. Change “triple” to “the triple”

L 225. Change “concentration of chlorpyrifos was” to “concentrations of chlorpyrifos were”


L 228. Change “range” to “the range”

L 229. Change “inhibition for Silver barb. To compare with” to “inhibition in Silver barb. In contrast to”

L 230. Change “performaces” to “performances”

L 231. Change “concentration” to “the concentration”

L 233. Change “inhibited” to “inhibited by”

L 234. Change “Pesticide” to “The pesticide”

L 235. Change “waterbodies nearby, it’s” to “water bodies nearby, its”

L 243. Change “environmental” to “environmentally”

L 244. Change “as biomarker of exposure of” to “as a biomarker of exposure to”

L 302. “Oncorhynchus mykiss” should be italicized.

Author Response

Dear Reviewer

All behalf of the authors, I would like to thank very much for your comments. We highly appreciate and have already corrected in the manuscript.

Best regards

Nguyen Van Cong

Author Response File: Author Response.pdf

Reviewer 2 Report

Summary:  Silver barb fish live in rice paddies where the fish are exposed to the pesticide chlorpyrifos ethyl.   The present report tested the susceptibility of Silver barb fish to the toxicity of chlorpyrifos ethyl.  Toxicity was estimated from inhibition of cholinesterase activity in brain.  The effects on food consumption and fish growth were measured.  The chlorpyrifos ethyl concentration that inhibited 50% of the cholinesterase activity in a 96 hour exposure was measured.  It was concluded that the level of chlorpyrifos ethyl found in rice paddy water caused fish to slow their growth, and resulted in inhibition of brain cholinesterase activity.


Major comment:  There is no report on the frequency of death.  Did fish die under any of the test conditions?

  1. Table 1.  Please use the English words for Sang and Chieu
  2. Figure 1 reports an LC50-96h value of 0.119 ppm.  However, Section 2.3.2 states that 1.19, 11.9 and 23.8 ppm values are equivalent to 1%, 10%, 20% of LC50-96h.  Please clarify this inconsistency.  Perhaps Section 2.3.2 has a typing error so that ppm is intended to be ppb.
  3. Section 3.2 line 167   typing error  23.9 ppm should be 23.9 ppb
  4. Please describe the method for measuring cholinesterase activity.
  5. Please describe how the brain was prepared for cholinesterase activity assays.  For example, did you use a nonionic detergent to dissociate cholinesterase from membranes?  Did you centrifuge to remove fat and cellular debris? 
  6. Table 5.  Please add a footnote to Table 5 that defines the abbreviations FI, DWG, SGR, and FCR.
  7. Section 3.3  line 231 and line 232.  Please check that you mean 1.19 ppm and 11.9 ppm.  It seems these values should be ppb.
  8. There is no report on the number of fish that died at various chlorpyrifos exposures.  The text states that fish death was recorded.  Please add this information. 

Author Response

Dear Reviewer,

On behalf of the authors, I would like to thank very much for your comments. We have checked, corrected and added more information to the manuscript. All were summarized in the attached file.

Thank you very much and best regards

Nguyen Van Cong

Author Response File: Author Response.pdf

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