Archives of Environmental Contamination and Toxicology (2022) 82:481-492
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Fig. 2 Elemental mass fraction in the <20 um grain size fraction of the two observed North Sea regions over the investigated time frame of ten
years. All error bars correspond to expanded uncertainties (U(k=2))
Estimation of Preliminary Reference Thresholds
For both regions, TCEs showed only little variation in mass
fractions over the observed time of ten years. Additionally, the
calculated LEFSs indicate slight to no TCE pollution within
this time frame. Nevertheless, both regions are partly affected
by anthropogenic influences, and hence a true background
value cannot be determined. Therefore, measured mass frac-
tions for the TCEs were used to estimate preliminary reference
thresholds. Two different methods were used (M2MAD and
TIF) whereby the M2MAD method provides more conserva-
tive limits than the more robust TIF method. Table 3 sum-
marizes the calculated threshold values for both regions. Both
approaches show consistent threshold values for each analyzed
TCE, thus indicating that the presented thresholds are a good
estimate for future studies. Furthermore, there are no substan-
tial differences between the thresholds of the two regions and
values were also determined using the entire dataset.
2 Springer
