Particulate Cr(VI) induces cell cycle arrest in bowhead whale lung cells. Data reflect the mean of at least 3 independent experiments. Error bars = Standard error of the mean. *Significantly different from untreated cells at the same timepoint (*p < .05, **p < .01). (A) and (B) are the flow cytometry histograms of cell cycle profiles. A, Cell cycle profiles after 24 h zinc chromate. B, Cell cycle profiles after 120 h zinc chromate exposure. C, Flow cytometry gating analysis after 24 h zinc chromate exposure. D, Flow cytometry gating analysis after 120 h exposure. E, Mitotic index after 24 or 120 h zinc chromate exposure in bowhead whale lung cells.