in-situ analysis of sediment and water quality

The Deltares Geochemical laboratory applies innovative in-situ measuring methods to gain insight into the geochemical processes of the water system. Thus, we determine the impact of policy measures intended to improve sediment and water quality and measure the consequences of new technologies that can affect the quality of sediments and surface water. In addition to testing and applying new technologies, we keep our knowledge of in-situ measuring up to date and develop new measuring methods.

Benefits of in-situ measuring

In-situ monitoring yields great benefits in comparison with traditional sampling because process information can be gathered in a short time at low cost. In addition, sources of error are avoided, for example selective sampling or disturbing chemical changes during transport. Real-time in-situ measurements are also used for screening purposes, so that based on the measurement information obtained, experts on site can select the right samples for further detailed laboratory analysis.

Applications

• Research into the impact of measures to combat blue-green algae (cyanobacterial blooms). As part of this effort, we take in-situ measurements of temperature (depth profiles), pH, redox condition, oxygen concentration, conductivity and blue-green algae concentration.
• Testing and development of in-situ sensors, including the development of solid-state microelectrodes (simultaneous analysis of redox-active substances in the top layer of sediment, see below).
• Research into the role of short-duration processes and events in the mobilisation and transport of polluting metals.
• Innovative monitoring in urban water systems; inventorising knowledge of innovative techniques and concepts for developing climate-adaptive urban water systems.
  

Geochemical consultancy

The experts at the laboratory act as independent consultants in commissions from commercial as well as government parties. We provide advice about the development of suitable monitoring strategies, measurement data and measuring method comparisons, as well as the quality control of measurement data and geodata interpretation.

Innovation

We are currently working on developing voltammetric microelectrodes to analyse the redox-active substances in the top layer of sediment simultaneously. This allows us to obtain an accurate understanding of the transport of substances and the interaction between the sediment and the overlying water column. Typical application of this innovative technique are environments with low oxygen concentrations (bottom water and sediment anoxia) and sulphidic environments.