Quantitative assessment on soil concentration of heavy metal–contaminated soil with various sample pretreatment techniques and detection methods

Detection and quantification of heavy metals in soil samples are significant in terms of environmental monitoring and risk assessment for metals. In order to improve the accuracy and precision to detect heavy metal, in this study, four standard samples (NASS-4, NASS-5, NASS-9, and NASS-16) were analyzed by evolving heating (electric heating plate, water bath, and microwave) and acidic systems (includes HCl, HNO3, HF, and HClO4). The result shows that different pretreatment methods have different effects on the extraction of heavy metal elements and five heavy metal elements (Cu, Zn, Pb, Ni, and Cr) were selected for optimization through pretreatment methods. Although the contents of heavy metals were same but we found diversity in the results. Under optimal conditions, the selected standard samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and atomic absorption spectroscopy (AAS), and the results were compared. The results show that different elements have their own most suitable detection methods, such as for Pb, the most suitable method is ICP-MS; and for Zn, the most suitable method is AAS. Pretreatment methods and detection techniques are combined to find and improve accuracy of results for certain elements. This study provides a reliable detection method for the accurate detection of heavy metals in the environment.