Institute of Environmental Engineering, Polish Academy of Sciences, 34 M. Skłodowskiej-Curie St., 41-819 Zabrze, Poland.
Molecules. 2022 Aug 3;27(15):4947. doi: 10.3390/molecules27154947.
The purpose of this study was to determine the heavy metal (HM: Cd, Cr, Cu, Ni, Pb, Zn, and Hg) content in particular chemical fractions (forms) of sewage sludge with different characteristics (primary and dewatered sludge) using conventional (CSE) and ultrasound-assisted (USE) BCR sequential extraction methods (Community Bureau of Reference, now the Standards, Measurements and Testing Programme). The concentrations of HMs were determined using inductively coupled plasma optical spectrometry (ICP-OES). Only mercury was assayed with cold vapor atomic absorption spectrometry (CVAAS). Ultrasound treatment was conducted in the ultrasonic bath (Sonic 5, Polsonic). The optimal sonication time (30 min) was determined using ERM-CC144 (Joint Research Center; JCR) certified reference material. The conducted experiment revealed that the use of ultrasound waves shortened the extraction time to 4 h and 30 min (Stages I to III). The recoveries (R) of heavy metals ranged from 62.8% to 130.2% (CSE) and from 79.8% to 135.7% (USE) for primary sludge, and from 87.2% to 113.2% (CSE) and from 87.8% to 112.0% (USE) for dewatered sludge. The only exception was Hg in dewatered sludge. The conducted research revealed minor differences in the concentrations and fractionation patterns for Cd, Ni, and Zn extracted from sludge samples by the tested methods. However, it was confirmed that the above findings do not significantly affect the results of a potential ecological risk assessment (with minor exceptions for Cd and Zn in the primary sludge), which is extremely essential for the natural use of sludge, and especially dewatered sludge (the final sludge). The shorter extraction time and lower energy consumption prove that ultrasound-assisted extraction is a fast and simple method for HM fractionation, and that it provides an alternative to the conventional procedure. Therefore, it can be considered a "green method" for the assessment of the bioavailability and mobility of heavy metals in solid samples.
本研究旨在使用常规（CSE）和超声辅助（USE）BCR 顺序提取方法（社区参考局，现为标准、测量和测试计划）确定具有不同特性（原污泥和脱水污泥）的污水污泥中特定化学形态（形式）的重金属（HM：Cd、Cr、Cu、Ni、Pb、Zn 和 Hg）含量。使用电感耦合等离子体光学光谱法（ICP-OES）测定 HM 的浓度。仅使用冷原子吸收光谱法（CVAAS）测定汞。超声处理在超声浴（Sonic 5，Polsonic）中进行。使用 ERM-CC144（联合研究中心；JRC）认证参考材料确定最佳超声时间（30 分钟）。进行的实验表明，使用超声波将提取时间缩短至 4 小时 30 分钟（阶段 I 至 III）。重金属的回收率（R）在原污泥中为 62.8%至 130.2%（CSE）和 79.8%至 135.7%（USE），在脱水污泥中为 87.2%至 113.2%（CSE）和 87.8%至 112.0%（USE）。唯一的例外是脱水污泥中的汞。进行的研究表明，用测试方法从污泥样品中提取的 Cd、Ni 和 Zn 的浓度和形态存在较小差异。然而，已证实这些发现不会对潜在生态风险评估的结果产生重大影响（原污泥中的 Cd 和 Zn 除外），这对于污泥的自然利用极其重要，特别是脱水污泥（最终污泥）。较短的提取时间和较低的能耗证明，超声辅助提取是一种快速简便的重金属形态分析方法，可为常规方法提供替代方案。因此，它可以被认为是评估固体样品中重金属生物有效性和迁移性的“绿色方法”。
