Multiyear dynamics of recent and legacy contaminants in a German hill-slope catchment (MS2 data)

Anthropogenic activities cause the release of vast amounts of contaminants into the environment and thus also into surface- and groundwaters. Regulatory monitoring determines whether critical threshold concentrations are surpassed, by mostly occasional probing. This irregular testing, however, does not capture the intricacies of intra- and inter-annual contaminant dynamics, such as the emergence and mobilisation of contaminants in response to water flows. We report the detection and tracing of five contaminants in the 'Hainich Critical Zone Exploratory' (CZE) in central Germany, a monitoring site established for regular sampling of groundwater from different depths and locations along a hill-slope recharge area. The insect repellent DEET (N,N-diethyl-m-toluamide) and the coniferous resin acid 7-ODAA (7-oxodehydroabietic acids), the latter being volatilised from wood burning in ovens, show phases of seasonal dynamics in line with their release mode. Further, and alongside legacy herbicides (simazine and the triazine transformation product hydroxypropazine) and the concurrent flame retardant and plasticiser TPP (triphenyl phosphate), mobilisation events emerge from periods of high precipitation and water flows. This investigation highlights the persistence and mobilization of anthropogenic contaminants even in pristine environments. It illustrates the importance of long-term research for understanding ecosystem processes. The results add a note of caution for regulatory monitoring since also legacy contaminant levels may considerably vary over time.

MS2 data is reported in the current study MTBLS3533.
MS1 data is reported in MTBLS8433.