Data generated to test nitrification inhibition of chromium. This dataset is associated with the following publication: Kapoor, V., M. Elk, X. Li, C. Impellitteri , and J. Santodomingo. Effects of Cr(III) and CR(VI) on nitrification inhibition as determined by SOUR, function-specific gene expression and 16S rRNA sequence analysis of wastewater nitrifying enrichments. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, USA, 147: 361-367, (2016).