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Sawada K, Inoue D, Wada Y, Sei K, Nakanishi T, Ike M. 2012. Detection of retinoic acid receptor agonistic activity and identification of causative compounds in municipal wastewater treatment plants in Japan. Environ Toxicol Chem 31: 307–315. DOI: 10.1002/etc.741

The authors of the above-noted paper hereby submit the following corrections. The paper includes the following errors:

  • 1.
    Recoveries of all-trans retinoic acid (atRA) and 13-cis retinoic acid (13cRA) for both influents and effluents were oppositely shown. Accordingly, we improperly applied the recoveries of 13cRA and atRA in the quantification of atRA and 13cRA concentrations in influents, respectively.
  • 2.
    In the quantification of RAs and 4-oxo-RAs concentrations in effluents, we mistakenly used the recoveries of them for influents.

Consequently, the authors reported several values incorrectly in the text in main body (pp. 313–314), Table 1, and the Supplemental Data. These corrections do not change the discussion and conclusions of the paper. Corrections are as follows:

Table 1. Concentrations of retinoic acids (RAs) and 4-oxo-RAs and all-trans RA (atRA) equivalents estimated from concentrations and atRA-equivalency factors of RAs and 4-oxo-RAs (atRA-EQchem) and from RA receptor α agonistic activity measured by yeast two-hybrid assay (atRA-EQbio) in wastewater treatment plant (WWTP) influents and effluents.
Wastewater treatment plantSampleConcentration (ng/L)aatRA-EQchem (ng/L)a, batRA-EQbio (ng/L)
atRA13cRA4-oxo-atRA4-oxo-13cRA
  • a

    Concentrations without and with recovery correction for RAs and 4-oxo-RAs were shown outside and in parentheses, respectively.

  • b

    Concentrations of RAs and 4-oxo-RAs less than their respective quantification limit (QL) in our analytical method were assigned a proxy value of QL/2.

AInfluent1.7 (7.3)<5.0 (<13.6)<0.5 (<0.6)1.7 (2.3)3.1 (9.1)19.2
 Effluent<0.5 (<1.4)<2.5 (<4.5)<0.25 (<0.4)<0.5 (<0.7)0.7 (1.4)1.6
BInfluent2.1 (9.0)<5.0 (<13.6)2.5 (3.3)70.2 (94.3)35.9 (54.1)12.9
 Effluent<0.5 (<1.4)<2.5 (<4.5)<0.25 (<0.4)<0.5 (<0.7)0.7 (1.4)0.5
CInfluent5.0 (21.5)<5.0 (<13.6)<0.5 (<0.6)8.6 (11.6)9.0 (26.9)29.0
 Effluent<0.5 (<1.4)<2.5 (<4.5)<0.25 (<0.4)<0.5 (<0.7)0.7 (1.4)1.4
DInfluent<1.0 (<4.3)<5.0 (<13.6)1.6 (2.1)32.0 (42.9)17.2 (24.4)17.8
 Effluent<0.5 (<1.4)<2.5 (<4.5)<0.25 (<0.4)0.6 (0.8)0.8 (1.6)19.5
EInfluent2.6 (11.4)<5.0 (<13.6)<0.5 (<0.6)12.0 (16.1)7.9 (18.4)13.9
 Effluent<0.5 (<1.4)<2.5 (<4.5)<0.25 (<0.4)<0.5 (<0.7)0.7 (1.4)0.2
FInfluent2.5 (10.8)<5.0 (<13.6)5.3 (6.9)70.0 (94.1)44.1 (66.0)38.7
 Effluent<0.5 (<1.4)<2.5 (<4.5)<0.25 (<0.4)<0.5 (<0.7)0.7 (1.4)0.5

Pages 313–314:

Fates of RAs and 4-oxo-RAs in WWTPs

  1. Top of page
  2. Fates of RAs and 4-oxo-RAs in WWTPs
  3. Preliminary risk assessment
  4. Supporting Information

The fates of RAs, 4-oxo-RAs, and total RARα agonistic activity in six WWTPs (WWTPs-A to -F) were investigated in March 2010 using a newly established quantitative method for RAs and 4-oxo-RAs (Supplemental Data, Fig. S4) and yeast two-hybrid assay. Because grab samples of influent and effluent collected at similar time were applied in the present study, concentrations of RAs and 4-oxo-RAs and total RARα agonistic activity in the samples were not necessarily representative; thus, we tentatively determined the fates and removal efficiencies of RAs, 4-oxo-RAs, and total RARα agonistic activity in WWTPs based on the results of these investigations.

Concentrations of RAs and 4-oxo-RAs and atRA-EQchem values, which were estimated from measured concentrations and atRA equivalency factors of RAs and 4-oxo-RAs, are shown in Table 1 with and without correction applying the recoveries of RAs and 4-oxo-RAs given in the Supplemental Data. Retinoic acid all-trans equivalents values, which were estimated from the RARα agonistic activity detected with the yeast assay, are also presented in Table 1. In influent samples, atRA, 4-oxo-atRA, and 4-oxo-13cRA were detected, and their concentrations without recovery correction ranged from <1.0 to 5.0 ng/L, <0.5 to 5.3 ng/L, and 1.7 to 70.2 ng/L, respectively. Their concentrations were from <4.3 to 21.5 ng/L, <0.6 to 6.9 ng/L, and 2.3 to 94.3 ng/L with recovery correction, respectively. By contrast, concentrations of 13cRA were below the quantification limit (<5.0 ng/L and < 13.6 ng/L without and with recovery correction, respectively) in all WWTPs although the compound was detected at concentrations below the quantification limit but above the detection limit in WWTPs-A (2.7 ng/L without recovery correction) and -E (1.5 ng/L without recovery correction). As a result, atRA-EQchem values in influent samples were estimated to be from 3.1 to 44.1 ng/L and 9.1 to 66.0 ng/L without and with recovery correction, respectively. Zhen et al. [11] reported that without recovery correction the concentrations of 4-oxo-atRA and 4-oxo-13cRA were from 4.7 to 10.4 ng/L and 2.3 to 7.1 ng/L, respectively, and atRA-EQchem were estimated to be from 18 to 41 ng/L in WWTP influents in Beijing, China. Thus, the contamination levels of our samples appeared to be comparable to previously reported contamination levels. The percentage of the atRA-EQchem value (without including the recoveries of RAs and 4-oxo-RAs) to the atRAEQbio value in influent samples ranged from 57 to 278%, except for WWTPs-A (16%) and -C (31%). When the recovery correction was performed, the atRA-EQchem value accounted for more than 93% of the atRA-EQbio value, except for WWTP-A (47%). These results suggested that four identified RAR agonists were responsible for the majority of RARα agonistic activity in WWTP influents. However, the results also suggested the possible occurrence of unidentified RAR agonists in WWTP influents, and further study is needed. In effluent samples, RAs and 4-oxo-RAs were undetectable and the atRA-EQchem value without including the recoveries of RAs and 4-oxo-RAs was estimated to be the lowest value of 0.7 ng/L in all WWTPs but WWTP-D, where 0.6 ng/L of 4-oxo-13cRA without recovery correction was detected. These results may suggest that RAs and 4-oxo-RAs were removed readily from the aquatic phase by the activated sludge treatment, regardless of the treatment process. The atRA-EQbio value was also reducedconsiderably (92–99% reduction) during the activated sludge treatment in most WWTPs. One exception was observed in an effluent sample from WWTP-D, in which the atRA-EQbio value (19.5 ng/L) was much higher than the atRA-EQchem value (0.8 and 1.6 ng/L without and with recovery correction, respectively). A similar result was observed in repeated investigations (data not shown). This suggests the occurrence of unidentified RAR agonist(s) within activated sludge treatment in WWTP-D, which must be studied further. RAR agonist(s) within activated sludge treatment in WWTP-D, which must be studied further.

Preliminary risk assessment

  1. Top of page
  2. Fates of RAs and 4-oxo-RAs in WWTPs
  3. Preliminary risk assessment
  4. Supporting Information

The possibility of biological adverse effects on aquatic animals by RAR agonists in WWTP effluents was assessed by comparing the RAR agonist contamination level in WWTP effluent determined in the present study and the RAR agonist concentrations at which detrimental effects were observed in previous studies. In this assessment, we applied the RAR agonist contamination level that was corrected with the recoveries of RAs and 4-oxo-RAs. In WWTP effluents investigated in the present study, the concentration of 4-oxo-13cRA was 0.8 ng/L at highest, while atRA, 13cRA, and 4-oxo-atRA were under the quantification limit (1.4 ng/L, 4.5 ng/L, and 0.4 ng/L, respectively).

Supporting Information

  1. Top of page
  2. Fates of RAs and 4-oxo-RAs in WWTPs
  3. Preliminary risk assessment
  4. Supporting Information

All Supplemental Data may be found in the online version of this article.

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etc_1940_sm_SuppData.doc202KSupplemental Data

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