The authors regret to inform that the following sentence has been misworded in the abstract. “Toxicity of Ni at pH 4 was negatively related to DOC concentration and amount of humic-like and fulvic-like DOC and positively related to fluorescence index.” should read “Toxicity of Ni at pH 4 was POSITIVELY related to DOC concentration and amount of humic-like and fulvic-like DOC and NEGATIVELY related to fluorescence index”. Also, there is a small error in the reference Vigneault et al. paper, the fourth author's name is misspelled. It should be Campbell not Camplbell. The authors would like to apologise for any inconvenience caused.