@misc{klein_investigation_of_2023, 
author={Klein, O.},
title={Investigation of the occurrence, distribution and fate of "Technology - Critical Elements" as potential "Emerging Contaminants" in the aquatic environment},
year={2023},
howpublished = {doctoral thesis: Universität Hamburg},
abstract = {Within this PhD thesis, a new ICP-MS/MS based method for the analysis of technology critical elements (TCEs) in sediments was developed and subsequently applied to real samples from the German Bight and the German Rhine. In terms of their potential supply risks or constraints, TCEs are elements or even minerals,that are considered critical both socially and economically. Compared to other metals, recycling pathways for TCEs are still incompletely developed or very inefficient. Thus, TCEs are emerging as potential new environmental pollutants. However, knowledge about their behavior in the environment is still scarce. This combined with the lack of official threshold or background values results in a lack of valid assessment of the potential environmental impact of TCEs Only a few suitable methods exist for the precise and reliable analysis of all important TCEs in environmental matrices. Unfortunately, these methods are often associated with rather complex sample preparation. Hence, part of this work was the development of a simple and robust analytical method based on inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS), which allows the quasi-simultaneous analysis of all currently relevant TCEs (Ga, Ge, Nb, In, Te, rare earth elements (REEs), and Ta). Here, the use of N2O as a reaction gas was employed, allowing to significantly increase the already good intensities and sensitivities of ICP-MS/MS when utilizing the commonly used O2 as a reaction gas. Subsequently, this method for multi-elemental analysis was applied to a ten-year time series (2010 - 2020) of North Sea sediment samples, taken from two regions in the German Bight. In this study, the variation of the TCE mass fractions in sediment over time, as well as possible regional differences were investigated. This allowed the establishment of preliminary reference background values for these regions. Results indicate that there are no significant differences over time or between the two regions, and calculated local enrichment factors suggest little or no anthropogenic input of TCEs on a current basis. The reference background values for TCEs in the North Sea based on this data may provide an important starting point for possible regulations or further studies on the fate of TCEs in the (marine) environment. For the second study, the optimized ICP-MS/MS method combined with multivariate statistics was used to gain first insights into the occurrence and distribution of TCEs in the German Rhine. In this context, special emphasis was laid on possible similarities between TCEs (Ga, Ge, Nb, In, Te, REEs, and Ta) and well-studied classical pollutants such as Ni, Cu, Zn, Cd, and Pb. Statistical analysis revealed that most TCEs exhibit similar behavior to,the classical heavy metals. In general, elevated mass fractions of Zn, Ge, In, La, Sm, and Gd along the Rhine indicate significant anthropogenic input. Thus, the findings and data of this study represent a good starting point to improve our understanding of the behavior of TCEs in complex river systems such as the Rhine. Furthermore, the data contribute to a better understanding of potential TCE sources in the North Sea, as the Rhine is an important main tributary to the North Sea, contributing significantly to the mass transport of suspended sediments as well as pollutants to coastal regions. This work demonstrates, the potential of ICP-MS/MS to analyze poorly studied analytes such as TCEs and thus to gain initial insights into their occurrence and fate within the environment. Secondly, the results of the studies indicate the potential negative impact of TCEs on the environment, which can be identified by analytical methods such as ICPMS/ MS in combination with multivariate statistics.},
note = {Online available at: \url{} (DOI). Klein, O.: Investigation of the occurrence, distribution and fate of "Technology - Critical Elements" as potential "Emerging Contaminants" in the aquatic environment. Universität Hamburg, 2023.}}