Determination of metals in printed wiring boards of waste mobile phones

Abstract

Metal contents of waste mobile phones represent a major environmental risk, especially considering the adoption of inappropriate management options in developing countries including open burning and disposal into surface water bodies. In this study the metal contents of mobile phone printed wiring board (PWB) samples were assessed. Sixty-two waste mobile phones of 15 brands were collected, dismantled, and their PWB samples were analyzed for Cu, Pb, Ag and Cd. The metal concentrations in the samples varied widely between and within brands. Among these metals, Cu and Pb were found to be at very high concentrations. The range (mean ± SD) of Cu and Pb concentrations were 94.1–532 g kg⁻¹ (250 ± 92.3 g kg⁻¹) and 7.0–46.2 g kg⁻¹ (20.1 ± 8.4 g kg⁻¹), respectively. All Cu and Pb concentrations exceeded toxicity threshold limit concentration (TTLC) regulatory limits used in characterizing wastes as hazardous in the state of California, USA. The mean Cu and Pb concentrations exceeded the corresponding TTLC limits by factors of 100 and 20, respectively. The Ag and Cd concentrations were in the range 59.4–759 mg kg⁻¹ (mean 227 ± 104 mg kg⁻¹) and ND – 15.6 mg kg⁻¹ (2.1 ± 3.3 mg kg⁻¹), respectively.

Keywords:

• electronic waste
• printed wiring board
• heavy metals
• toxicity characterization