From rivers to the sea: determination and tracing of TCEs in natural waters

TCEs have a wide-spread range of applications and are released into the aquatic environment in various ways. For their sound determination in natural waters not only new analytical methods are needed but also reference materials for method validation. Even though a wide variety of certified reference materials (CRMs) of different water matrices are available, certified values of many elements, especially TCEs, do not exist. In this study, an online preconcentration method coupled with ICP-MS/MS was used for the quantification of 34 elements among which are 21 TCEs. The method was applied to 17 water CRMs and measured data is combined with a comprehensive literature review on non-certified values in the CRMs resulting in the suggestion of consensus values for various TCEs.

The method is applied to a set field samples from German rivers and from the North Sea in order to trace different inputs of TCEs into the aquatic environment: In and Ga ware analyzed as tracers for offshore wind farms where they are applied in corrosion protection systems. The Gd anomaly was used as a proxy of coastal and riverine inputs into the North Sea in an attempt to differentiate anthropogenic from geogenic signal. The concentrations in seawater ranged between 0.011 ng L^-1 ± 0.001 ng L^-1 and 0.27 ng L^-1 ± 0.15 ng L^-1 for In and between 1.37 ng L^-1 ± 0.05 ng L^-1 and 4.9 ng L^-1 ± 0.5 ng L^-1 for Ga and Gd anomalies of up to 4 were found in the North Sea.