Pond water quality in agricultural landscapes is estimated to reflect surrounding agricultural activities on the local scale. This especially applies to the field-specific application of pesticides which are considered to be mainly transported into aquatic systems by surface runoff and local-scale wind drift. However, there is evidence of many pesticides with ubiquitous occurrences in different aquatic settings, questioning current theories on their transport and fate. This study from North-eastern Germany presents monitoring results of pesticides in agricultural ponds and adjacent shallow groundwater. The results show that individual substances do not only occur simultaneously in both, surface water and groundwater but also follow similar concentration dynamics. This does not only apply to single locations but also to different locations with different land use intensities. Pesticides found comprise substances currently in use, metabolites and legacy compounds. Since for many of the detected substances concentrations are higher in surface water, groundwater exfiltration can be excluded as an advective source for pond pollution. The findings rather demonstrate a similar ubiquitous state of pollution in both, surface and subsurface aquatic environments whose dynamics are driven by a common factor. We suspect the substances are trapped in aquatic systems underlying delayed removal. Furthermore, regional subsurface hydrology may be responsible for temporal occurrences and concentration dynamics of individual substances.

Primary Presenter: Karin Meinikmann, Julius Kühn-Institute (karin.meinikmann@julius-kuehn.de)

Authors:

Stefan Lorenz, Julius Kühn-Institute  ()

Matthias Stähler, Julius Kühn-Institute  ()

Kathrin Fisch, Julius Kühn-Institute  ()