Effects Of Road Deicing Salts On Soil Microorganisms
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| Year of publication | 2005 |
| Type | Conference abstract |
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| Description | The use of road deicing salts in winter was many times reported to result in negative effects on surrounding terrestrial ecosystems. In our study, effects of deicing salts (mostly NaCl) on soil properties were evaluated and risk for soil microorganisms was assessed by two different approaches: 1) soil microbial biomass and its respiration activity was measured, 2) soil extract toxicity was tested in bacterial tests. Three similar mountain forest stands were chosen along the contour road and soil was sampled on the slope above the road (control) and 1m, 10m, and 30m below the road (along the runoff). Overall salinization was recorded as main effect on soil properties: Na+ concentrations increased toward the road up to 100mg/L; soil pH(water) was increased below the road with maximum pH 8 in 1m distance; exchange pH was near zero nearby the road; base saturation steeply increased to 100% toward the road. Microbial biomass, basal and substrate induced respiration were significantly reduced nearby the road when compared with control locality. These trends were apparent also after weighting the measures by Corg content which appears to be other factor affecting these parameters. These results show clearly the causality between soil salinization by deicing salts and decrease of soil microbial quality. Opposite results were shown by Vibrio fischeri and Pseudomonas putida toxicity tests of soil extracts. High stimulation was recorded, especially for salinized samples nearby the road. The different results between these two approaches imply that bacterial toxicity tests alone are not suitable for soil risk assessment in such cases. Only measurement of soil microbial community status can provide true information about the risks. |
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