Evaluation of Surface Water Quality Using Various Indices for Heavy Metals in Sasolburg, South Africa

Round 1

Reviewer 1 Report

Introduction: it should be specified the criteria for choosing the heavy metals, why mercury was not included?

Materials and methods

 2.3 Sample analysis

The limit of quantification for each element should be indicated as the recovery.

Results and conclusions

Could be interesting compare the results obtained with other similar publications especially for  aluminium, iron, molybdenum and manganese that were detected in high concentrations.

Author Response

Introduction: it should be specified the criteria for choosing the heavy metals, why mercury was not included?

Response: The reseason why mercury is not included has been included.

Materials and methods

 2.3 Sample analysis

The limit of quantification for each element should be indicated as the recovery.

Response: The LOQs and LODs have been included.

Results and conclusions

Could be interesting compare the results obtained with other similar publications especially for  aluminium, iron, molybdenum and manganese that were detected in high concentrations.

Response: Comparison has been added in the conclusion.

Reviewer 2 Report

The main purpose of the study was to determine the concentrations of heavy metals Al, As, Cd, Co, Cr, Fe, Mn, Mo, Ni, Pb, Sb, Se, Sr, Tl and V as well as such parameters as pH, electrical conductivity (EC), total dissolved solids (TDS) in surface waters used for domestic and farming activities collected during the dry and wet seasons at Meulsteenpan Lake, Coalplex Stream, Natref Stream in Sasolburg, Free State, South Africa (2019-2020). In the paper the pollution indices were also presented: contamination factor (Cf), modified degree of contamination (m-Cd), modified heavy metal index (m-HPI), heavy metal evaluation index (HEI), Nemerov index (NeI), weighted arithmetic water quality index (WQI), estimated daily  intake (EDI), non-carcinogenic risk of water consumption (HQ), carcinogenic risk of water consumption (R). The value of these parameters reveal the trend of water quality at each section. The paper is well-organized and the study is sufficiently performed. However, I recommend some modifications (in Abstract abbreviations DWAF, WHO, EPA etc. should be explain/or avoided; in my opinion part 3 should be presented in Supplementary Material and in Table 2 remove the word “Scheme”). The result analysis is very accurate and adequate, lacks of major errors. Therefore, in my opinion the publication deserved to be published in the Water.

Author Response

However, I recommend some modifications (in Abstract abbreviations DWAF, WHO, EPA etc. should be explain/or avoided; in my opinion part 3 should be presented in Supplementary Material and in Table 2 remove the word “Scheme”). The result analysis is very accurate and adequate, lacks of major errors. Therefore, in my opinion the publication deserved to be published in the Water.

Response: Abbreviations have been defined. Part 3 has been placed as supplementary information