Effects of road deicing salts on soil microorganisms

Abstract

ABSTRACTin this study, the effects of road salting on the quality of forest soils near the road were monitored in the Krkonoše Mountains (Czech republic). Physical, chemical properties and microbial parameters of soils were determined and the toxic potentials of soil water extracts were evaluated using the bacterial tests (Microtox and Pseudomonas putida growth inhibition test). increased concentrations of na + ions (up to 100 mg/kg) and pH values up to 8 were found closer to the road. Microbial biomass and respiration activity were significantly reduced at the roadside (anova; P < 0.05), and the metabolic quotients showed that the microbial community was apparently under stress. large stimulation of Pseudomonas putida growth was determined, especially for salinized samples closest to the road. oppositely, results showed the unsuitability of bacteria toxicity tests in such cases of pollution. assessment of intrinsic soil microbial communities is more ecologically relevant and shows the effects that cannot be detected by bacterial toxicity tests.

Substrate Factors Determine Roadside Vegetation Structure and Species Richness: A Case Study Along a Meridional Gradient in Fennoscandia

“…Substrate pH and salinity were higher on roadsides that at sites further from the road (Table 1 ). Higher substrate pH on roadsides, also found by other authors, may result from the use of alkaline gravel in road construction (Černohlávková et al 2008 ). Simple regressions indicated a strong positive correlation between substrate density (g cm −3 ) and salinity (g kg −1 OM) ( p < 0.0001; r = 0.64), confirming that salinity is linked to the composition of road-building material and road maintenance practices.…”

“…Both substrate pH and salinity on roadsides were not related to meridional gradient ( p = 0.5268 and p = 0.7895, respectively). Salinity is a strong stressor for roadside vegetation as well as for soil organisms, including microorganisms beneficial to plants (Černohlávková et al 2008 ). However, substrate density was related to meridional gradient and the higher latitude, the higher substrate density (coarser substrate structure) was found ( p = 0.0295).…”

Long‐term ferrocyanide application via deicing salts promotes the establishment of Actinomycetales assimilating ferrocyanide‐derived carbon in soil

“…Moreover, the diversity of 13 C-labelled bacteria differed highly from those of the roadside soils: in soil D and F, ferrocyanide was used as C source mainly by Actinomycetales, while in soil W members of Acidobacteria (Gp3, Gp4, Gp6), Gemmatimonadetes (Gemmatimonas) and Gammaproteobacteria (Thermomonas, unclassified Xanthomonadaceae) assimilated the 13 C. All those taxa were previously found to be enriched in bioreactors containing mining effluent, indicating their capacity to degrade thiocyanate and cyanide (Kantor et al, 2015). Surprisingly, neither Kineosporia nor Mycobacterium assimilated ferrocyanide-derived C in soil W although their presence at similar abundances when compared with soil D and F. This indicates an adaptation of the microbial community on long-term ferrocyanide application and consequently its permanent presence as additional C source: in soils first exposed to ferrocyanide, various microorganisms assimilate the new available C but at the end were outcompeted by Actinomycetales, resulting in their increased abundance in roadside soils when compared with soil W. However, it has to be taken into account that ferrocyanide is not applied purely to the road environment but as anticaking agent via deicing salts that itself could impact microbial soil community (Cernohlavkova et al, 2008;Hofman et al, 2012). Although we cannot exclude a long-term salt related influence, we assume that the impact of previous applied deicers could be neglected in our system as (i) the soil was sampled in November before road deicing salt was first applied in the actual winter period and (ii) salt applied during the last winter was quickly leached due to high precipitation (1280 mm y À1 ) in the sampling area.…”

The effect of de-icing roads with salt on the environment in Krakow (Poland)

“…The salt remains in the subsurface layers of soil for several months after application and in its deeper layers for the entire year. Moreover, high salt concentrations may even appear during summer vegetation bloom and the consequences of historical NaCl application may be long-term due to salt retention (Siyal et al 2002, Godwin et al 2003, Černohlávková et al 2008, Kelly et al 2008, Findlay & Kelly 2011. This duration depends on many factors, and one of the most important is the amount of precipitation.…”

“…Younger plants are considered to be less tolerant of salinity due to their shallower roots. Elevated salinity also has a negative impact on microorganisms, additionally disturbing the soil environment (Czerniawska-Kusza et al 2004, Yuan et al 2007, Černohlávková et al 2008, Hofman et al 2012.…”