Chromosomal aberrations and nuclear irregularities observed in root tip cells of A. cepa following treatments with different concentrations of pulp and paper mill effluent. (a) Sticky metaphase, (b) chromosome loss, (c) anaphase bridge, (d) c-mitosis, (e) tripolar anaphase, (f) vagrant chromosome, (g) bridge at telophase, (h) micronucleated cell, and (i) binucleated cell.