Sediment sampling in Likolampi Mikkeli, winter 2019. Photo credits: Pekka Forsman, copyright GTK.

Studies on the chemical content of the sediments in the Hanhilampi and Likolampi ponds – Does the contaminants in the sediment pose a threat for groundwater quality?

RAINMAN project press release

As part of the RAINMAN Project, the Geological Survey of Finland (GTK) and the City of Mikkeli studied the chemical content of the sediments in the ponds Likolampi and Hanhilampi and estimated the risk of possibly contaminated sediments to groundwater quality in the Hanhikangas aquifer. In both ponds, the bottom sediment contains elevated concentrations on cadmium, mercury, zinc and aliphatic petroleum hydrocarbons. In the Likolampi pond, elevated concentrations of chromium, copper, lead and nickel were detected as well. The higher concentrations were found from the top of the sediment. This indicates that external pollutant loads to the ponds still exist.

Following this study, the stormwater catchment areas and the current quality of the stormwater flow will be researched paying special attention to contaminants analysed and detected from the bottom sediments of the studied ponds.
The study report is now available in Finnish at

Contact: Anu Eskelinen, Geological Survey of Finland GTK