Iron (II) is measured in abandoned mine drainage using a phenanthroline method (Standard Methods for the examination of water and wastewater, method 3500-Fe). In 9. solution and diluted to 100.0 ml. The solution turns deep red and is measured at 510 nm. A series of standards from 0.50 -2.00 ug/ml iron(II) are prepared and their absorbance measured. The data for these solutions is given below. Using this data calculate the concentration of iron(II) in the original mine drainage samples. Fe Conc (ug/ml) Absorbance 0.00 0.50 1.000.134 1.50 2.00 0.002 0.045 0.096 0.196 Mine drainage 0.115 0.120