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Archives of Environmental Contamination and Toxicology (2022) 82:481-492 
All sediment samples were freeze-dried (Christ Gefri- 
ertrocknungsanlagen, Osterode, Germany) and wet-sieved, 
using a cascade of polyamide sieves (RETSCH GmbH, 
Haan, Germany) and either a continuous-flow (Hereon) or a 
standard centrifuge (BSH) (Thermo Scientific1M HeraeusTM 
BiofugeTM StratosT!M Zentrifuge, Fisher Scientific GmbH, 
Schwerte, Germany) to obtain the <20 um grain size frac- 
tion. The wet-sieving was performed in a closed setup using 
1 L of Milli-Q water. Leaching of analytes into the water 
used for sieving is negligible (5x 107°%-5 x 107°% for all 
analytes considered) (Nham 2017). After wet-sieving tripli- 
cates of each sediment sample were digested via microwave- 
assisted acid digestion using either a MARS Xpress or a 
MARS 6 (CEM Corp., Kamp Lintfort, Germany) following 
che digestion protocol of Zimmermann et al. (2020): 50 mg 
of sieved sediment was digested using a mixture of 5 mL 
HNO-,, 2 mL HCl, and 1 mL HBF, at 180 °C for 300 min. 
Two sediment reference materials GBW 07313 and GBW 
07311 as well as the basalt reference material BCR-2 were 
digested in a similar manner. All samples were prepared in 
iriplicates. Certified and measured values for the certified 
reference materials (CRMs) and respective recoveries for the 
quantified elements together with the respective measure- 
ment mode, LOD, and LOQ values of the method are given 
in supplemental information Tables A.2 and A.3. 
Table 1 Overview of all campaigns from which samples were 
included in this study 
Campaign code Research vessel Administration Sampling die 
CE10001 Celtic Explorer 
CE11002 Celtic Explorer 
CE12002 Celtic Explorer 
PE364 Pelagia 
PE385 Pelagia 
CE15001 Celtic Explorer 
CE16011b Celtic Explorer 
LP20160725 Ludwig Prandtl 
CE17001 Celtic Explorer 
AT248 Atair 
AT261 Atair 
AT275 Atair 
LP20200629 Ludwig Prandtl 
of two different regions were analyzed: one close to the coast 
of Heligoland (South) and a second further offshore in the 
North Sea (North). A list of all samples including coordi- 
nates is given in the supplemental information Table A1 
while Fig. 1 shows a map with the sample locations. 
Sample Digestion 
Prior to any further sample preparation, each sample was 
analyzed for its grain size distribution using either a Laser 
Particle Sizer (Analysette 22, FRITSCH, Ida-Oberstein, Ger- 
many) or by a sieve analysis. 
instrumentation and Measurement Procedures 
All measurements were conducted using a tandem mass 
spectrometer with inductively coupled plasma (ICP-MS/ 
MS) using an optimized method for the measurement of 
Fig. 1 Overview of the sam- 
pling stations in the German 
Bight. Red dots correspond to 
stations of the North region 
while blue dots show the 
South region. The dashed line 
highlights the German exclusive 
economic zone (EEZ) 
r1EEZ 
Nortb 5% 
North 562 
NoL 
ST) Ti, 
... 
& Til 
HWgye 
HPAEB3 _ 
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