Does road salting induce or ameliorate DOC mobilisation from roadside soils to surface waters in the long term?

TY - JOUR

T1 - Does road salting induce or ameliorate DOC mobilisation from roadside soils to surface waters in the long term?

AU - Green, Sophie M.

AU - Machin, Robert

AU - Cresser, Malcolm S.

PY - 2009/6

Y1 - 2009/6

N2 - Soils down slope of roads have been affected over decades by road salting in the UK uplands. Salt additions to fresh soil facilitate dispersal of organic matter so there is a potential risk of release of DON and DOC to nearby rivers where these run parallel to roads. Over time, however, salting enhances soil pH of naturally acid soils, and thus organic matter degradation through to CO2, thereby, lowering soil organic matter content. In addition any relatively labile organic matter may have already been dispersed. Thus, it is hypothesised that enhanced DOC mobilisation should only be a potential problem if soils not previously exposed to salt become heavily exposed in the future. This paper combines data from field observations and laboratory simulations to elucidate mechanisms controlling organic matter mobilisation processes to determine what controls spatial and temporal trends in DOC concentrations in soil solutions down slope of roads. Organic matter solubilisation is dependent on the degree of road salt exposure soils have had. The laboratory experiment provided evidence that there are two competing effects upon which solubilisation is dependent (a) pH suppression and (b) sodium dispersion. Other organic matter solubility models, if correct, link quite well with the authors "when it's gone, it's gone" hypothesis.

AB - Soils down slope of roads have been affected over decades by road salting in the UK uplands. Salt additions to fresh soil facilitate dispersal of organic matter so there is a potential risk of release of DON and DOC to nearby rivers where these run parallel to roads. Over time, however, salting enhances soil pH of naturally acid soils, and thus organic matter degradation through to CO2, thereby, lowering soil organic matter content. In addition any relatively labile organic matter may have already been dispersed. Thus, it is hypothesised that enhanced DOC mobilisation should only be a potential problem if soils not previously exposed to salt become heavily exposed in the future. This paper combines data from field observations and laboratory simulations to elucidate mechanisms controlling organic matter mobilisation processes to determine what controls spatial and temporal trends in DOC concentrations in soil solutions down slope of roads. Organic matter solubilisation is dependent on the degree of road salt exposure soils have had. The laboratory experiment provided evidence that there are two competing effects upon which solubilisation is dependent (a) pH suppression and (b) sodium dispersion. Other organic matter solubility models, if correct, link quite well with the authors "when it's gone, it's gone" hypothesis.

KW - Road salt

KW - Sodium chloride

KW - DOC concentration

KW - Upland river

KW - DISSOLVED ORGANIC-CARBON

KW - DEICING SALTS

KW - MATTER

KW - RIVER

KW - HORIZONS

KW - SCOTLAND

UR - http://www.scopus.com/inward/record.url?scp=67349126928&partnerID=8YFLogxK

U2 - 10.1007/s10661-008-0369-4

DO - 10.1007/s10661-008-0369-4

M3 - Article

SN - 0167-6369

VL - 153

SP - 435

EP - 448

JO - ENVIRONMENTAL MONITORING AND ASSESSMENT

JF - ENVIRONMENTAL MONITORING AND ASSESSMENT

IS - 1-4

ER -