Winter Salt Research Articles

Stormwater quality and microbial ecology in an urban rain garden system

Rain gardens are an alternative to traditional drainage, able to lower flood risk and reduce environmental contamination from stormwater. Removal of contaminants by rain gardens is driven by both physical processes (such as filtration and sedimentation) and biological metabolic processes by soil microorganisms. To better understand rain garden performance, this study explored the impact of rain gardens on pollution removal and microbial composition and function using rain gardens fed real stormwater from a busy road. Each rain garden had different grain size and hydraulic conductivities as these parameters have been argued to impact pollution removal. All four rain gardens were able to reduce the contaminant load in the stormwaters, reducing the concentration of dissolved metals, suspended solids and chemical oxygen demand. Significantly, road salting in the winter did not cause dissolved metals to be released from the rain gardens, suggesting that rain gardens can continue to reduce contaminant loads during winter salting regimes. Some variation in pollutant removal was seen between the soils tested, but overall no clear trend could be identified based on grain size and hydraulic conductivity with all rain gardens performing broadly similarly. The rain garden soil altered the microbial community in the stormwater, resulting in greater taxonomic evenness and functional richness in the effluent water compared to the influent. Functional richness of the soils was also higher than that of the input waters, indicating that the microbes in the rain gardens were able to perform a wider range of functions than those of the influent. Effluent and soil microbiology was more impacted by sampling date than soil grain size, which may be a result of the soil communities maturing and changing over time. As greater numbers of rain gardens are installed to tackle flooding from climate change, it is important to ensure the environment is protected from urban contaminants in the stormwater. The results in this study further highlight the ability of rain gardens to undertake this important task.

Road salt pollution alters sex ratios in emerging mosquito populations

De-icing road salt is a persistent emerging pollutant in temperate freshwater systems, where winter salting is necessary for road and pedestrian safety. Experts argue that road salts may increase salt-tolerant mosquito populations and, potentially, disease transmission in urban areas. Only adult females consume bloodmeals and may carry zoonotic diseases. While there are some species with naturally occurring male-biased sex ratios, it is unclear whether road salt differentially affects male and female mosquitoes to alter sex ratios. We hypothesized that road salts would masculinize emergence sex ratios and decrease female success because females may face higher exposure to stressors during their lengthy juvenile development compared to males. We measured mosquito emergence sex ratios of control (0 g/L added salt) and salt (4.5 g/L added salt) mesocosms in southern Ontario, Canada across the West Nile Virus season (May to October). We found female-biased sex ratios (i.e., <50% male frequency) in both 0 and 4.5 g/L. While mosquito abundance was significantly higher in 4.5 g/L compared to 0 g/L, road salt significantly increased the proportion of emerging males from 32.8% to 40.8% (Negative Binomial Model; Estimate ± SE = 0.283 ± 0.108; P = 0.009); mosquitoes shift their sex ratios from female-biased towards parity (50:50) in response to salt. Our study illustrates the need to evaluate sex-specific abundance in pollution-related mosquito population studies. By showing a shift toward more male mosquitoes emerging in high salinity compared to control treatments, our results suggest that road salts may have the potential to decrease female mosquito success and indirectly reduce disease transmission in cities.

Impact of salinization on lake stratification and spring mixing

AbstractAnthropogenic freshwater salinization affects thousands of lakes worldwide, and yet little is known about how salt loading may shift timing of lake stratification and spring mixing in dimictic lakes. Here, we investigate the impact of salinization on mixing in Lakes Mendota and Monona, Wisconsin, by deploying under‐ice buoys to record salinity gradients, using an analytical approach to quantify salinity thresholds that prevent spring mixing, and running an ensemble of vertical one‐dimensional hydrodynamic lake models (GLM, GOTM, and Simstrat) to investigate the long‐term impact of winter salt loading on mixing and stratification. We found that spring salinity gradients between surface and bottom waters persist up to a month after ice‐off, and that theory predicts a salinity gradient of 1.3–1.4 g kg−1 would prevent spring mixing. Numerical models project that salt loading delays spring mixing and increases water column stability, with ramifications for oxygenation of bottom waters, biogeochemistry, and lake habitability.

Salinization of Alpine rivers during winter months

Human-induced (i.e., secondary) salinization affects aquatic biodiversity and ecosystem functioning worldwide. While agriculture or resource extraction are the main drivers of secondary salinization in arid and semi-arid regions of the world, the application of deicing road salt in winter can be an important source of salts entering freshwaters in cold regions. Alpine rivers are probably affected by salinization, especially in highly populated mountain regions, although this remains to be explored. In this study, we analyzed multi-year conductance time series from four rivers in the European Alps and demonstrated that the application of deicing road salt is linked to peaking rivers’ salinity levels during late winter/early spring. Especially in small catchments with more urban surfaces close to the rivers, conductance increased during constant low-flow periods in late winter and was less correlated with discharge than in summer. Thus, our results suggest that small rivers highly connected to urban infrastructures are prone to considerable salinity peaks during late winter/early spring. Given the low natural level of salinities in Alpine rivers, the aquatic biodiversity might be significantly affected by the recorded changes in conductance, with potential consequences on ecosystem functioning. Thereby, we urge the research community to assess the impact of secondary salinization in Alpine rivers and call for an implementation of management practices to prevent the degradation of these pristine and valuable ecosystems.

Investigating the Pollution Characteristics and Primary Components Source Apportionment of PM10 in Nanjing Port

In order to investigate the characteristics and the sources of PM 10, the Nanjing port was selected as the sampling site for atmospheric PM10 samples collections. The sampling was introduced during represent months in summer and winter. Then the elements, ions and OC/EC chemical components were detected by ICP-MS, ion chromatography and carbon analyzer, respectively. The results showed that the average concentration of atmospheric PM 10 in summer and winter for Nanjing port Was 88.1 ± 31.9 μg/m 3 and 136.9 ± 76.8 μg/m 3, respectively. The concentrations of in organic secondary Components In summer and winter were25.4μg/m 3 and 40.8μg/m 3, accounting for 28.9% and 31.1% of the total PM 10, respectively; the concentration was highest for NO 3 - in summer and for SO 4 2- in winter. There is obvious difference between the concentration of carbonaceous components in summer and winter, and the concentration of total carbonaceous components was 88.1 ± 31.9 μg/m 3 and 136.9 ± 76.8 μg/m 3, accounting for 24.4% and 39.7% of the total PM 10, respectively; Variation of primary carbonaceous components is the reason Causing the difference s. Source apportionment results indicate d that the soil dust and coal combustion, metallurgy, motor vehicle, ship and sea salt were the main contributors To the PM 10 in Nanjing port. Soil dust contributed most (33%), and the contribution percentages of sea salt and ships were approximately 6.4% and 6.6%, respectively. The contribution s of sea salt and ship emissions in winter were slightly higher in winter than that in summer.

REDUCING ROAD SALT APPLICATION BY CONSIDERING WINTER MAINTENANCE NEEDS IN PARKING LOT DESIGN

INTRODUCTION Winter snow and ice can have a significant impact on our mobility, whether on foot or by car. Alongside plowing, arguably the greatest tool in combating snow and ice is salt. The most commonly used salt for winter maintenance is Sodium Chloride (NaCl), the same salt used in food and water softeners, is applied to roads, sidewalks, and parking lots as it is an effective deicer when temperatures are between 0°C and −12°C. Studies have shown that deicing with salt reduces accidents by 88% and injuries by 85% (Salt Institute 2017). The effectiveness of road salt, as well as its relative affordability, means that as much as four million tonnes may be applied annually in Canada for deicing (Environment Canada 2012). However, while salt is relatively inexpensive to purchase, there are a number of external costs that are becoming increasingly apparent. These include corrosion of vehicles and infrastructure like concrete, bridges, and water mains; damage and staining to the interior and exterior of bu...

Salt-tolerant trees usable for Central European cities - Review

The present text is focused on an actual problem of planting of inappropriate tree taxa in many cities. It explains the causes of contaminated soils by winter salt management and principles of the toxic effect on plants. The paper summarizes the problem and brings solution. Town places with salt-contaminated soil should not be fitted with: spruce (Picea), pine (Pinus), linden (Tilia) and maples (Acer). On the other hand, resistant species are: ash (Fraxinus), poplar (Populus), willow (Salix), silverberry (Eleagnus), black locust (Robinia). Both lists of sensitive and salt-tolerant tree species have been presented. Salt-tolerant tree should be preferred before all the others species.

Soil as a reservoir for road salt retention leading to its gradual release to groundwater

Road salt application elevates Na and Cl concentrations throughout the year in many surface water and groundwater systems. This study explores the role of soils in extending the lag time between road salt application and the delivery of Na and Cl to shallow groundwater in a temperate environment. Intact soil cores were collected near karst springs at both an urban and a rural site at distances of 1 m, 5 m, and 13 m from nearby roads that experience winter salting. Cores were manipulated in the lab to simulate various field conditions; treatments included irrigation with: 1) deionized (DI) water (DI group) as a control, 2) NaCl solution (salt group) to mimic prolonged exposure to road salt, or 3) NaCl followed by DI water (recovery group) to mimic winter road salting followed by dilute rainfall in spring. In the first NaCl irrigation of the salt and recovery groups, soils retained 62% of the applied Cl and 66% of the applied Na on average, which was largely stored in the porewater. Throughout the 5 week study, Ca, Mg, and K were elevated and the pH was depressed in leachate from salt group compared to DI group cores due to cation exchange. Likewise, cation exchange enhanced Na retention so that salt and recovery group cores retained half of the applied Na at the end of the experiment, compared to a quarter of the Cl. Na and Cl retention were greater for soils from the rural site, which is characterized by higher organic matter (OM) and sand content, faster infiltration, and lower bulk density than for the urban site, which has higher bulk density and more silt and clay. Furthermore, extractable Cl in untreated field soils was positively correlated with soil water content, OM, and sand content, suggesting that these properties may control retention. We assume Cl retention to be the result of porewater retention, microbial uptake, and chlorination of soil OM. After the addition of 2000 mg Cl to the salt group cores, non-conservative Cl behavior ceased because the retention capacity of the soils had been exhausted. Recovery rates during DI flushes of recovery group cores indicate that these soils slowly release Na and Cl for at least 2.5–5 months following salt application. This gradual release from soils helps to explain the year-round persistence of high salt concentrations in some surface waters and groundwaters.

Do salt and low temperature impair metal treatment in stormwater bioretention cells with or without a submerged zone?

Although seasonal temperature changes and (road) salt in winter and/or coastal stormwater runoff might interfere with the metal treatment performance of stormwater bioretention cells, no previous study has evaluated the effect of these factors and their interactions under controlled conditions. In this 18week long study 24 well established pilot-scale bioretention columns were employed to evaluate the individual and combined effect(s) of low/high temperature, salt and presence of a submerged zone with an embedded carbon source on metal removal using a three factor, two-level full factorial experimental design. In most instances, the three factors significantly influenced the metal outflow concentrations and thus the treatment performance; the effect of temperature depended on the metal in question, salt had an overall negative effect and the submerged zone with carbon source had an overall positive effect. Despite these statistically significant effects, the discharge water quality was generally markedly improved. However, leaching of dissolved Cu and Pb did occur, mainly from bioretention cells dosed with salt-containing stormwater. The highest concentrations of metals were captured in the top layer of the filter material and were not significantly affected by the three factors studied. Overall, the results confirmed that bioretention provides a functioning stormwater treatment option in areas experiencing winter conditions (road salt, low temperatures) or coastal regions (salt-laden stormwater). However, validation of these results in the field is recommended, especially focusing on dissolved metal removal, which may be critically affected under certain conditions.

Assessing the Vulnerability of Winter Maintenance Material Storage Facilities

AbstractThis research examines the vulnerability of the winter maintenance salt supply to depletion and the associated risk costs in Ohio using Ohio Department of Transportation (ODOT)-specific data pertaining to the amount of salt storage, number of trucks, and lane kilometers maintained by each county. These data were combined with the number of snowfall events in each county to determine the failure probability. The results indicated that the probability of exceeding the salt capacity ranged from less than 0.01 to 61%, with an average of 23.1%. Sensitivity and importance analyses were conducted to determine the change in probability of exceedance due to a one-unit change in each parameter and to examine the influence of each random variable in the reliability analysis on the variance of the limit state, respectively. The parameter with the highest importance was the salt applied during light snowfall, while the brine applied has a low importance. Annual risk costs were estimated using the purchase and ...

Bioretention: assessing effects of winter salt and aggregate application on plant health, media clogging and effluent quality

Bioretention offers the potential to better match pre-development water balances while improving stormwater quality. The now extensive body of research shows bioretention to be a viable and effective option in the management of stormwater, however there continues to be a demand for information related to cold climate design and performance. To study the impact of winter road salting on bioretention functions, a salt and aggregate mixture was applied to outdoor, bioretention mesocosms with soil, mulch and vegetation layers. Freezing of the media within mesocosms was found to increase the infiltration rates. Smaller increases in infiltration rates occurred for mesocosms exposed to the salt and aggregate mixture, suggesting that media clogging due to high suspended solids loading may be counteracting the effects of expansion due to freezing. Sodium and chloride were temporarily retained in the bioretention media, but were subsequently flushed by infiltrating water. Plant species, Aster nova angliae ‘Red Shades’ and Panicum virgatum were shown to be capable of withstanding high salt exposure. The exposure of the bioretention soils to de-icing materials did not alter the media's ability of the media to remove contaminants. No evidence of increased heavy metal mobility during this study was observed. Overall, results support the potential for application of bioretention facilities in cold climate regions.

Chloride Released from Three Permeable Pavement Surfaces after Winter Salt Application

AbstractFew studies exist on how chloride from chloride‐based deicers is transported in infiltration‐based stormwater control measures. In 2009, the U.S. Environmental Protection Agency (USEPA) constructed a 0.4 ha parking lot in Edison, New Jersey, that was surfaced with permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). Each surface type has four equally sized, lined sections that direct all infiltrate to separate 5.7 m3 collection tanks. The USEPA acute criterion for aquatic life (860 mg/l) was exceeded in events immediately following a snow event. Concentrations of the infiltrate exceeded the detection limit (5 mg/l) year round but did not exceed the USEPA chronic toxicity (230 mg/l) after April. The chloride concentration decreased with cumulative rainfall since previous snow event, and a power regression described this relationship. In the power regression, the coefficient (b) described the initial concentration following a snow event, and the exponent (m) described the rate in which chloride was flushed through the system with infiltrating water. PC had the largest coefficient (5,664) and largest absolute exponent (−0.92), followed closely by PICP (b = 4,943 and m = −0.87), and distantly by PA (b = 2,907 and m = −0.67). The differences in release rate were proportional to the measured surface infiltration rates of 4,000; 2,400; and 200 cm/h for PC, PICP, and PA, respectively. These results will assist those who manage or regulate stormwater where receiving waters are chloride impaired.

Numerically and Experimentally Based Reliability Assessment of a Concrete Bridge Subjected to Chloride-Induced Deterioration

AbstractMaintaining an adequate safety level in concrete bridges under gradual degradation due to traffic and environmental actions is not only an expensive task, but also filled with some level of uncertainty. Degradation in itself is not easily quantifiable because numerous aspects reduce the load-bearing capacity of a concrete bridge. Furthermore, the effects of preventive maintenance and rehabilitation actions are difficult to predict. Chloride ion ingress is an important aspect of durability design and maintenance, especially in regions where winter salt is commonly applied for traffic safety. This paper introduces a feasible approach to analyze the effects of chloride-induced deterioration on the overall safety level, which is validated by the application to a real highway bridge, which was demolished after 38 years of service. Concrete samples were extracted from this bridge and chemical analyses were performed to determine the chloride concentration profile in the concrete. Once the present chlori...

Morphofunctional State of the Adrenal Glands in Albino Rats under Conditions of Toxic Stress Caused by Cadmium Salt in Winter and Summer Periods

We studied the morphology and function of the adrenal glands in male and female albino rats in cadmium intoxication during winter and summer periods (January and July). In animals of the control group, sex-related differences in the total area of the adrenal glands and in the size of their zones were revealed. In females, zones of adrenal gland were larger than in males. In winter months, these differences were most pronounced. Analysis of seasonal differences in the area of the adrenal glands in males revealed no significant differences in winter and summer months. Irrespective of the season and gender, cadmium chloride treatment led to an increase in the size of the adrenal glands. Cadmium salts caused more pronounced functional strain in males in winter months and in females in summer.

Characterization of Interface Bond of Ultra-High-Performance Concrete Bridge Deck Overlays

Critical components of the nation's bridge network, concrete bridge decks, are deteriorating at a rapid rate. This deterioration can be attributed to several factors; however, winter salt application, the diffusion of chlorides to the reinforcing steel, and eventual corrosion of the reinforcement are primary culprits. Multiple protection solutions, include concrete protective systems, sealers, additional cover to the reinforcement, membranes, and epoxy-coated reinforcement, but each solution has shortcomings and does not completely address the problem. Ultra-high-performance concrete, a relatively new material with exceptional strength and durability characteristics, may be a solution to these problems when it is used as a thin overlay on bridge decks. An experimental study was performed to evaluate the bond strength between an ultra-high-performance concrete overlay and a normal concrete substrate with different types of surface textures, including smooth, low roughness, and high roughness. Slant shear and splitting prism tests were performed to quantify the bond strength under compression combined with shear and under indirect tension. Test results demonstrated that under compressive loading, the bond strength was greater than the strength of the substrate when the surface texture was greater than the standard smooth finished mortar surface. For the bond strength under indirect tension, results were not highly sensitive to the surface roughness. In both cases, the measured bond strengths fell within the ranges specified in the American Concrete Institute's Guide for the Selection of Materials for the Repair of Concrete.

Ansatz zur Beurteilung von chloridbelasteten Stahlbetonbauwerken mit Bewertung der Restlebensdauer

AbstractDie Sicherstellung eines ausreichenden Zuverlässigkeitsniveaus im Rahmen der Erhaltung von Bauwerken und insbesondere Betonbrücken, welche durch Verkehrs‐ und Umwelteinflüsse einer kontinuierlichen Verschlechterung im Laufe ihrer Lebenszeit unterliegen, ist in der Regel eine komplexe und teure Aufgabenstellung. Besonders in Regionen mit Streusalzeinsatz in der Winterzeit beeinflusst die Chloridbelastung sowohl den Entwurf als auch die Erhaltung der Bauwerke durch ihren Einfluss auf die Dauerhaftigkeit wesentlich. In diesem Beitrag wird eine Bewertungsstrategie für die durch die Chloridbelastung hervorgerufene Zustandsverschlechterung von Betonstrukturen und deren Auswirkung auf das Sicherheitsniveau sowie die verbliebene Lebenszeit an einem Fallbeispiel vorgestellt. Hierbei werden die Entnahme von Proben, deren Untersuchung, die inverse Analyse des Eindringverhaltens und infolge die Prognose der Chloridkonzentration im Bauteil, die Vorhersage der Korrosionsentwicklung über die Zeit und schließlich die Bestimmung des gegenwärtigen und zukünftigen Zuverlässigkeitsniveaus unter Beachtung der normativ festgelegten Grenzzustände für Tragfähigkeit und Gebrauchstauglichkeit behandelt. Schlussendlich werden unterschiedliche Erhaltungsstrategien in Bezug auf die zu erwartenden Lebenszykluskosten verglichen.Approach for the Assessment of Concrete Structures Subjected to Chloride Induced DeteriorationThe maintenance of an adequate safety level of concrete bridges under their gradual degradation due to traffic and environmental actions during service life is an expensive, problematic and questionable task. Chloride ion ingress is an important aspect of durability design and maintenance, especially in regions where winter salt application for traffic safety is common, e. g. for highways. A feasible approach for the assessment of chloride induced deterioration and its consequences on the safety level, remaining service life and thus maintenance planning will be presented by a case study. Steps include the extraction of samples, laboratory test, inverse analysis and prognosis of chloride ingress, prediction of likely corrosion propagation over time and determination of the current and future safety level with regard to code based service limit states and ultimate limit states. Finally different maintenance strategies are compared with respect to the total life cycle costs.

Study of Cl-containing urban aerosol particles by ion beam analytical methods

Fine (aerodynamic diameter < 2.5 μm) and coarse (10 μm ⩾ aerodynamic diameter ⩾ 2.5 μm) mode urban aerosol samples were collected with 2-h time resolution in the frame of several sampling campaigns between 2007 and 2009 in downtown Debrecen, East-Hungary. The elemental composition (for Z ⩾ 13) of the samples was measured by particle induced X-ray emission (PIXE). On this basis sources of urban aerosol were determined by factor analysis. For both size fractions a source characterized by high chlorine content were found. However, the origin of the Cl-containing aerosol could not be ascertained. Further investigation of samples characterized with high Cl content were done on the ATOMKI Scanning Nuclear Microprobe Facility in order to determine the possible chemical composition of these particles and thus the potential sources. Morphology, size and elemental composition for Z ⩾ 6 of around 1000 coarse mode particles were determined by using STIM (Scanning Transmission Ion Microscopy), light-element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the obtained dataset in order to group the particles; correlations between different elements were also calculated. Five possible sources of Cl were identified, from which four were anthropogenic: winter salting of streets, agriculture through fertilizers, buildings and industry; the natural group was sea-salt.

Time-lapse resistivity investigations for imaging saltwater transport in glaciofluvial deposits

Five intersecting resistivity sections have been measured in glaciofluvial deposits hosting an aquifer of regional importance situated along a heavy traffic highway in Sweden. The winter salt spreading has caused a regular salinity increase through the years. For imaging the transport of saltwater in the aquifer, the sections were measured exactly in the same location before and after winter, and interpreted using a time-lapse inverse procedure. Some auger drilling and RCPT data were available for correlation. After winter, the resistivity had generally decreased under the water table and increased above it. The decrease in resistivity in the saturated zone is interpreted as a plume of more saline groundwater created by de-icing salt from the road. The increase in the upper layer can be explained by changes in temperature and soil moisture. The study shows that time-lapse resistivity investigations has potential for imaging hydraulic pathways in complex hydrogeological environments.

Size and XAD fractionations of trihalomethane precursors from soils

Soil organic matter is an important source of allochthonous dissolved organic matter inputs to the Sacramento–San Joaquin Delta waterways, which is a drinking water source for 22 million people in California, USA. Knowledge of trihalomethane (THM) formation potential of soil-derived organic carbon is important for developing effective strategies for organic carbon removal in drinking water treatment. In this study, soil organic carbon was extracted with electrolytes (deionized H 2O and Na- or Ca-based electrolytes) of electrical conductivity bracketing those found in Delta leaching and runoff conditions. The extracts were physically and chemically separated into different fractions: colloidal organic carbon (0.45–0.1 μm), fine colloidal organic carbon (0.1–0.025 μm), and dissolved organic carbon (DOC) (<0.025 μm); hydrophobic acid (HPOA), transphilic acid, and hydrophilic acid. Two representative Delta soils, Rindge Muck (a peat soil) and Scribner Clay Loam (a mineral soil) were examined. Results showed that less than 2% of soil organic carbon was electrolyte-extractable and heterogeneous organic fractions with distinct THM reactivity existed. Regardless of soil and electrolytes, DOC and HPOA fractions were dominant in terms of total concentration and THMFP. The amounts of extractable organic carbon and THMFP were dependent on the cation and to a lesser extent on electrical conductivity of electrolytes. Along with our previous study on temperature and moisture effects on DOC production, we propose a conceptual model to describe the impacts of agricultural practices on DOC production in the Delta. DOC is mainly produced in the surface peat soils during the summer and is immobilized by accumulated salt in the soils. DOC is leached from soils to drainage ditches and finally to the Delta channels during winter salt leaching practices.

Elevated NH3 and NO2 air concentrations and nitrogen deposition rates in the vicinity of a highway in Southern Bavaria

Abstract A transect study consisting of air concentration and deposition measurements of nitrogen compounds was performed to estimate the potential influence of car emissions on the nitrogen input to ecosystems. Therefore, two transects each consisting of 4 plots, the first in a coniferous forest and the second one in an extensively farmed grassland, were installed perpendicular to a highway south of Munich (Bavaria). Both profiles were influenced mainly by car emissions and showed only small local influences caused by agricultural activities. In the framework of a pilot study based upon denuder measurements we found a strong temporal dependency of both nitrogen dioxide (NO2) and ammonia (NH3) concentrations on traffic density. In the main study air concentrations of NO2 and NH3 were measured by passive samplers; they used as the basis for the estimation of dry deposition. These estimations have been compared with the results of analyses from simultaneously conducted canopy throughfall deposition and open air bulk measurements of nitrate (NO3−) and ammonium (NH4+). Additionally, within the forest transect the variety of different soil vegetation species was recorded and quantified. We obtained a strong gradient of gas concentrations along both profiles. Whereas the bulk deposition remained quite constant along the non-forested transect, the nitrogen throughfall deposition rate diminished substantially with the distance from the highway. The deposition rate at the forest edge was twice of that inside. The nitrogen load estimated for the examined forest in the vicinity of the highway was comparable to other forest ecosystems situated near diffuse emission sources from agriculture. It could be shown that changes in soil composition and soil vegetation along the forest transect are caused by decreasing nitrogen deposition with distance from the highway. The application of road salt in winter leads to further impacts.