b is the length of the light path intercepted by the absorption species in the absorption cell, and c is the concentration of the absorbing species. The specific wavelengths used were as follows: chromium, 357.87 nm; cadmium, 228.80 nm; Arsenic, 193.7 nm; and lead, 283.31 nm; the detection limits for the metals were as follows: lead, 0.05 mg/L; chromium, 0.02 mg/L; cadmium, 0.002 mg/L; arsenic 0.2 mg/L [23]. The calibration yielded a straight line, and the absorbance of solutions of unknown concentrations was measured and the concentration was determined from the calibration curve.