Germanium speciation study in soil from an electronic waste processing plant area

Abstract

Purpose Germanium (Ge) is known as a Technology Critical Element (TCE) and has been widely used in electronic and industrial products. Waste electronic and electrical equipment (WEEE) containing germanium goes to WEEE treatment plants. The transfer of Ge in the environment makes it necessary to get to know its mobility, reactivity, and chemical transformations in soil. The objective of this research was to develop a methodology for germanium speciation in soil under pressure from storage, processing, and recovery from electrowaste. Materials and methods Thirty soil cores (30 cm long) were collected from an area around a WEEE plant, using a Humax soil sampler. Soil magnetometry methods were used for the first time during the determination of soil sampling points for germanium. After basic physicochemical analysis (pH, Eh, total element concentration using the ICP-MS technique), soil samples were prepared for germanium speciation. The optimisation and validation of a methodology for determining Ge species in easily-leached fractions of soil collected from areas around an electrowaste plant, was studied using Ion Chromatography-Inductively Coupled Plasma-Mass Spectrometry (IC-ICP-MS). Chromatographic conditions were optimised, taking soil matrix effects into account. Optimised Ge extraction from the soil included: extraction time, type of extractants, extraction support using shaking, and ultrasound. Results and discussion The Ge species (Ge(IV), monomethylgermanium (MMGe), and dimethylgermanium (DMGe)) were successfully separated after 12 min on a Dionex IonPac AS9-HC column with ammonium nitrate and potassium sodium tartrate as an elution phase. The highest extraction efficiency was achieved by using 100 mM NH4NO3 with 1 mM potassium sodium tartrate as an extractant, that washes out Ge from soils within 4 h. In most cases, the soils contained a Ge(IV) form. Germanium methyl derivatives were only found in a few soil samples. Our research showed that germanium concentration in the studied area was as high as 7.64 mg.kg−1, with an average concentration of 3.51 mg.kg−1. The results allowed the creation of a correlation matrix, which identified many strong correlations. Conclusion This research confirmed the impact of a WEEE plant on the increase of the Ge content in topsoil, when in direct proximity. Increased germanium content occurred in soil samples located north of the emitter, which is consistent with the prevailing wind direction. The study confirmed that the soil magnetometry method is applicable for detecting TCE. Soil samples with the highest content of germanium had a very high magnetic susceptibility and there is a correlation between these parameters.

Electronic Waste Problem in Developing Nations: Mismanagement, Health Implications, and Circular Economy Opportunities

“…Chemical pollutants found from e-waste may distribute in the direction of the prevailing wind surrounding the waste electronic and electrical equipment (WEEE) processing plant. Soil samples demonstrate an enhanced germanium (Ge) concentration in places where the wind originates mostly from the emitter position (21). Various studies have provided evidence of the effect of leaching on the upper soil layer, with the potential consequence of contaminating the subsoil profile.…”

“…These consequences can make root development difficult and limit plant access to crucial nutrients and moisture. Furthermore, the proclivity of plant roots to absorb e-waste toxins such as heavy metals and chemical compounds raises worries about possible bioaccumulation (21,31). These pollutants are persistent in soil matrices, with some remaining for decades, increasing their long-term impact on ecosystems.…”

“…The hazardous substances persist in the soil for extended periods, impairing soil fertility and disrupting essential soil microorganisms that support plant growth (21,33). This degradation of soil quality not only affects agricultural productivity but also poses risks to environmental stability.…”

Atomic spectrometry update: review of advances in elemental speciation

“…Thus, a method for Ge speciation in soil around a storage, processing and waste facility was developed with a focus on understanding its mobility, reactivity and transformation. 83 Soil sampling locations were established using in situ low-field volume magnetic susceptibility ( κ ) measurements. From 30 selected sampling points, two 30 cm long soil cores were collected using a Humax soil sampler.…”