The results from “Investigation of road lakes 2023” show that the influence of road salt poses a problem for the water chemistry and circulation pattern in a number of lakes near main roads in Østfold, Oslo, Akershus, Buskerud, Telemark and Vestfold.
– In 10 lakes, natural circulation in the water bodies had stopped due to salt inputs, so that there was no oxygen left at the bottom, so-called salt-induced oxygen loss. 28 out of 37 lakes had varying degrees of salt impact, writes the Norwegian Public Roads Administration in a press release.
Chronic effect
Some of the lakes had very high concentrations of chlorine. In, for example, Patterødtjern near Moss and Gjerdsrudtjern in Oslo, the concentrations are so high that they are considered to have a chronic effect on a number of aquatic organisms, especially plankton algae.
– The lake survey gives us important knowledge about the impact of road salt and other traffic pollution in lakes near roads. It lays the foundation for how we can salt smarter to protect life in water, while at the same time safeguarding traffic safety and maintaining passability on the roads, says Erlend Aakre, director of Transport and society at the Norwegian Road Administration.
Works for less salting
The Swedish Road Administration’s director of operations and maintenance, Bjørn Laksforsmo, says they are working towards less salting, but that the winter of 2023 was demanding.
– The use of salt has decreased since 2017/2018, although we see a slight increase in 2023. Among other things, we have introduced compulsory training for drivers, which has been effective in reducing salt consumption, says Laksforsmo.
(© NTB)
