An increasingly recognized problem in the world is stormwater runoff and its generation of pollutants in urban areas. Stormwater treatment technologies have therefore increased in implementation to prevent this pollution. One of these preventions are detention ponds, which primary function is the equilibration of water, but have also proven to have the capacity to remove many particle-bound pollutants by sedimentation. What's not as known is to what extent.

The investigated detention ponds were compared to see to what extent they had accumulated particle-bound elements such as heavy metals, phosphorus and sulphur. This because it is essential to clarify whether they embody ecotoxicological hotspots and if when dredged will have sediment classified as hazardous waste.

What was found in this study was that there was no significant difference in accumulation of pollutants or sediment depending on inlet or outlet, a difference between these could still be seen though by looking at the figures. The sediment of some of the detention ponds also had levels of the investigated elements higher than existing guideline values recommend for living organisms in the sediment and could also be classified as hazardous waste when emptied.

More investigations need to be done, for example about how hydrology, plant uptake and design affect the sedimentation of pollutants to know for sure how the accumulation of pollutants in detention ponds work.