Over the past few weeks many tonnes of salt have been poured onto our roads, to ensure that we can travel safely through the icy conditions, but where has all this salt gone?

Although it was life saving for us, unfortunately it is unlikely to be the good news for our streams and rivers, which will likely be the recipients of much of this salt as it washes away into verges and drainage systems come the thaw.

Previous studies of upland roadside soils in Cumbria, that would normally be naturally acidic, have highlighted that runoff from roads that have had long-term road applications of salt can dramatically raise the soil pH (i.e. make them more alkaline) down slope in upland areas where acidic soils normally prevail.

This increase in soil pH dramatically changes nitrogen cycling in soils down slope and the loss of organic matter. The Nitrogen cycle is a key process at the bottom of the food chain to ensure healthy ecosystems. Changes to the Nitrogen cycle cause an increase in leaching of nitrogen in to down-slope rivers (not good for the water!) and the loss of soil organic matter over a long period can have a significant impact on the ‘quality’ of the soil.

Ecologists are also observing salt-loving plants appearing alongside roads. The road salt may be creating seaside conditions at road edges inland. Many of these salt-tolerant plants are right at home in the more salty soil in road verges. In Carmarthenshire this is evidenced by the presence of Danish Scurvygrass.