Toxic Floods


Proof-of-concept study for investigations on riverine and urban sediment deposits as flood induced pollution archives in subtropic/tropic areas


Frank Lehmkuhl


+49 241 80 96064


  Map of the study area in southeast India Copyright: PGG Map of the study area.

River floods in urban and settled areas are common ecohazards in terrestrial surface water systems resulting dominantly from rapid and intensive rainfall in the river catchment. Since many anthropogenic emissions from industrial, municipal and agricultural sources are discharged to river systems, flood events are an important driver for dispersion of these anthropogenic pollutants and (eco)toxic effects. They are partly stored in the floodplains after such flooding events. Therefore, floodplain sediments record anthropogenic activities that are coupled with any sort of emission of organic and inorganic compounds and consequently serve as an archive for cultural and industrial history.
In South and Southeast Asia, rivers are often highly polluted and the corresponding particulate matter is a temporary sink for numerous lipophilic pollutants as well as heavy metals. Furthermore, floods, in particular driven by the monsoon, are highly affecting river systems in these ecozones. However, following the pollution history by analyzing appropriate riverine sediment archives along the river course have not been applied so far in these regions.

  Two pictures showing the sampling and another sample site at the Cooum River Copyright: F. Lehmkuhl Sampling (top) and another sample site (bottom) at the Cooum River.

Since a comprehensive study on such sediment archives needs to meet some substantial preconditions in particular, the access to appropriate sediment archives, such as periodically or aperiodically flooded wetlands, and knowledge on the spectrum of pollutants thorough pre-investigations are required. Consequently, this project proposal is intended to be a proof-of-concept study testing a complex tropic river system for geochemical studies on the flood-driven dispersion of particle associated contamination. The cooperation with the local partners of the Indian Institute of Technology Madras was and still is essential for the success of this venture.

Duration 03/2019 - 10/2019
Funding German Research Foundation (DFG) – Sachbeihilfe
Project partners Prof. Dr. Jan Schwarzbauer – Institute of Geology and Geochemistry of Petroleum and Coal, RWTH Aachen
Prof. Dr. B. S. Murty – Department of Civil Engineering, IIT Madras
Prof. Dr. Balaji Narasimhan – Department of Civil Engineering, IIT Madras