Assessment of Pb, Cd, Cr and Ag leaching from electronics waste using four extraction methods

Abstract

Heavy metals present in electronic components may leach upon disposal and therefore pose significant environmental hazards. The potential leaching of Pb, Cd, Cr and Ag from PC cathode ray tubes, printed circuit boards (PCBs), PC mice, TV remote controls, and mobile phones was assessed. After controlled crushing, each component was extracted using the Toxicity Characteristic Leaching Procedure (TCLP), EPA Method 1312 (SPLP), NEN 7371 (Dutch Environmental Agency), and DIN S4 (Germany). The TCLP consistently leached the greatest amounts of Pb from all components. The SPLP, NEN 7371 and DIN S4 extracted relatively small amounts of metals compared with the TCLP and were not considered effective as leaching tests for e-waste. The smallest size fraction (< 2 mm) of CRT glass and PCBs leached significantly (p < 0.05) highest Pb via the TCLP. A modified TCLP removed 50.9% more extractable Pb compared with the conventional procedure.

Keywords:

• Ag
• Cd
• Cr
• Pb
• electronics waste
• leaching

Acknowledgments

Support from the Sigma Xi Scientific Society, the Ball State University Center for Energy, Research, Education and Service (CERES), and the Ball State University Honors College is gratefully acknowledged.

Notes

∗n = 4.

∗BDL = Below detection limit (0.33 mg/l for Pb, 0.017 mg/L for Cd; 0.06 mg/L for Cr; 0.04 mg/L for Ag).

∗Significant at P < 0.05.