Distributions of Radiocesium and Plutonium in the Korean Seas and North Pacific after the Fukushima Accident, 2011–2014

Round 1

Reviewer 1 Report

The paper is devoted to the radioactivity measurements in the surface waters. While all measurements are presented using units Bq/kg whicj is more usually used for the radioactivity on the solid fractions. The clarification of the solid-liquid concentrations should be done. Espesially for the Yellow sea the discussion bout the suspended sediments concentration dsuring the measurements should ne added.

 

Minor comments: 

 Line 38 During Chornobil accident there were no direct release to the ocean, the were release to the river Dnipro and significant part of radionuclides remained in the sediments of the river reservoirs. 

 Line 69, CMW is not shown on the Fig 1 while discussed in text

 Line 103 137Cs missprint

 Line 314  units of A0 missed

Line 325 discussion of half life can be extended, why half-life differ from half life of radioactive decay, how it cab be related with sea water exchange rates for discussed basins

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is describing the surface distribution of cesium and plutonium radioactive isotopes in Korean seas and in part of Pacific ocean after Fukushima accident. Authors present interesting and valuable results from several ocean cruises about radioactive tracers, nevertheless that they are 10 years old.

I  would like to congratulate authors for very nice paper, it is well written with minor spell check required.

I have just few comments,

- two sentences in rows 112 and 113 are beginning with the same phrase, please rephrase

- superscript missing at 137 in row 103 and at 239+240 in row 128

- paragraphs 2.2.1 and 2.2.2 are beginning with "First", please remove or rephrase

- missing bracket in rows 136 and 137

Author Response

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Reviewer 3 Report

This article presents distributions of radiocesium ⁽¹³⁴Cs and ¹³⁷Cs) and plutonium isotopes ⁽²³⁸Pu and ^239+240Pu) in surface waters of the Korean seas and the North Pacific between 2011 and 2014, after the Fukushima accident. The results obtained and residence time calculations presented here are very interesting for predicting and evaluating the influence of potential radionuclides releases into the marine environment.

Here are some comments and suggestions:

- for the global manuscript: radio-isotopes are commonly presented in ascending order: ¹³⁴Cs and ¹³⁷Cs, ²³⁸Pu and ^239+240Pu;

- l. 11: a space is needed "2011_and";

- l. 14: dates are commonly presented in ascending order: 2010 and 2012;

- l. 35: according to the IAEA Nuclear Data Section, t_1/2 (¹³⁷Cs) = 30.08 years;

-l. 40: according to the IAEA Nuclear Data Section, t_1/2 (²⁴⁰Pu) = 6561 years;

- Figure 1: north arrow, scale and source of the map are required. Please also add sampling locations;

- l. 104 and 108: please homogenize "co-precipitate";

- Figure 2: looking at the color scale, the activities of ¹³⁷Cs seem to be higher in 2012, despite the uncertainties mentioned in the text;

- Figure 2: please add letter or/and number for each picture (for example: A-B-C-D or A1-A2 for ¹³⁴Cs and B1-B2 for ¹³⁷Cs…);

- l. 187: sentence suggestion “¹³⁴Cs > 0.3 mBq kg^-1 at the four stations”;

- l. 197: please, can you explain the sentence “our radiocesium data did not match spatially in 2011 and 2012”;

- l. 202 and Figure 3: considering the input of artificial radionuclides in the Korean seas after the Fukushima NPP accident, why ¹³⁷Cs does not increase, like ¹³⁴Cs, in 2011?;

- Figure 3: please complete the caption “the comparisons of the annual mean activities of ¹³⁴Cs and ¹³⁷Cs in the Korean seas from 2006 to 2012.”;

- l. 224: to close the parenthesis is needed “(the closest city…”;

- Figure 4: please add letter or/and number for each picture;

- Figure 5: please add letter or/and number for each picture. Sections #1, #2 and #3 are not clear, please highlight them;

- Figure 6: this figure is very clear with letters. Please add the description of each letter in the caption;

- l. 348-349: repetition of “immediately”;

- l. 351-352: repetition of “we also”;

- l. 355: the residence time of ¹³⁷Cs does not correspond to that given in section 3.5 (l. 325);

- l. 385: “seas”;

- l. 386: the residence times of ¹³⁷Cs do not correspond to those given in the abstract, in the section 3.5 (l. 325) and in the conclusion (l. 355);

- References: please complete references, when possible, with the DOI.

Author Response

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Author Response File: Author Response.pdf