Leaching behavior, health risk, and safe landfill thresholds of trace elements in end‑of‑life multi‑crystalline silicon photovoltaic cells

Abstract

The rapid expansion of the photovoltaic industry will inevitably generate a huge amount of end‐of‐life (EoL) multi‐crystalline silicon (MC‐Si) waste, raising increasing concerns regarding its potential environmental impacts under landfill disposal. This study systematically investigated the total contents and leaching behavior of trace elements (TEs) in EoL MC‐Si photovoltaic cells (PV) under landfill‐relevant conditions. A health risk assessment framework was developed to derive risk‐based landfill thresholds under groundwater ingestion, soil particles ingestion, and soil dermal contact exposure, and Monte Carlo simulation was conducted to quantify its uncertainty. The results showed that Ag, Sn, Pb, and Cu were the dominant TEs, accounting for 98.3% of the total detected TEs content. Pb had the highest leaching concentration (29.4 mg L ⁻¹ ) and accounted for 69.51% of the total leached TEs on a molar basis. Pb leaching substantially exceeded regulatory thresholds, indicating significant leaching toxicity. Health risk assessment showed that groundwater ingestion was the dominant exposure pathway and that total non‐carcinogenic risk (TSNCR) exceeded the acceptable threshold at landfill quantities of 7.48 × 10 ³  kg for adults and 7.92 × 10 ³  kg for children. Total carcinogenic risk (TSCR) became non‐negligible at 1.51 × 10 ⁴  kg for adults and 6.51 × 10 ⁴  kg for children, and unacceptable at 1.51 × 10 ⁶ and 6.51 × 10 ⁶  kg, respectively. Pb was the major health risk driver, accounting for 99.7% of TSNCR and 83.4% of TSCR. Direct landfill disposal of EoL MC‐Si PV should be stringently regulated, and Pb‐containing solder should be replaced or removed prior to disposal.