Archives of Environmental Contamination and Toxicology (2022) 82:481-492
https://doi.org/10.1007/s00244-022-00929-4
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Occurrence and Temporal Variation of Technology-Critical Elements
in North Sea Sediments—A Determination of Preliminary Reference
Values
Ole Klein'?®@. Tristan Zimmermann '@-. Anna Ebeling
Daniel Pröfrock'®
w) . Madita Kruse? - Torben Kirchgeora
Received: 2 December 2021 / Accepted: 22 March 2022 / Published online: 26 April 2022
© The Author(s) 2022
Abstract
As interest in the investigation of possible sources and environmental sinks of technology-critical elements (TCEs) continues
to grow, the demand for reliable background level information of these elements in environmental matrices increases. In
this study, a time series of ten years of sediment samples from two different regions of the German North Sea were analyzed
for their mass fractions of Ga, Ge, Nb, In, REEs, and Ta (grain size fraction < 20 um). Possible regional differences were
investigated in order to determine preliminary reference values for these regions. Throughout the investigated time period,
only minor variations in the mass fractions were observed and both regions did not show significant differences. Calculated
local enrichment factors ranging from 0.6 to 2.3 for all TCEs indicate no or little pollution in the investigated areas. Conse-
quently, reference values were calculated using two different approaches (Median +2 median absolute deviation (M2MAD)
and Tukey inner fence (TIF)). Both approaches resulted in consistent threshold values for the respective regions ranging
from 158 ug kg”! for In to 114 mg kg”! for Ce. As none of the threshold values exceed the observed natural variation of
TCEs in marine and freshwater sediments, they may be considered baseline values of the German Bight for future studies.
X Daniel Pröfrock
daniel.proefrock@hereon.de
Institute of Coastal Environmental Chemistry, Inorganic
Environmental Chemistry, Helmholtz-Zentrum Hereon,
Max-Planck Str. 1, 21502 Geesthacht, Germany
Department of Chemistry, Inorganic and Applied Chemistry,
Universität Hamburg, Martin-Luther-King-Platz 6,
20146 Hamburg, Germany
Department Mechanical Engineering, HTWG Hochschule
Konstanz, Alfred-Wachtel-Straße 8, 78462 Konstanz,
Germany
Marine Sciences Department, Marine Chemistry Laboratory
- Shipping and Environment, Marine Sediments Section,
Bundesamt für Seeschifffahrt und Hydrographie (BSH),
Wüstland 2, 22589 Hamburg, Germany
2 Springer
