Investigations of vegetation stress along non-paved roads treated with a range of magnesium chloride (MgCl₂) application rates utilized 60 roadside and 79 drainage plots on 15 and 18 roads, respectively. Evaluations were completed of foliar damage, plant health, biotic and abiotic damage incidence and severity, soil and foliar chemistry and other common site and stand characteristics of Pinus contorta, Populus tremuloides, Picea engelmannii, Abies lasiocarpa, and lower elevation plots dominated by shrubs and grasses. High concentrations of soil magnesium and chloride (400-500 ppm), high foliar chloride (2,000-16,000 ppm depending on species) and high incidence of foliar damage were measured in roadside plots along straight road segments in the first 3 to 6.1 m adjacent to treated roads. In drainage plots, where water is channeled off roads, high concentrations of both magnesium and chloride ions and associated foliar damage were measured between 3 and 98 m from the road. High incidence of foliar damage and elevated ion concentrations were not apparent in control plots along non-treated roads. Lodgepole pine appeared to be the most sensitive species, while aspen accumulated the most chloride and exhibited the least amount of damage. Foliar chloride concentrations strongly correlated with percent foliar damage for all species (r = 0.53 to 0.74, p < 0.0001) while the incidence of biotic damages did not correlate well. Positive relationships between foliar chloride and magnesium chloride application rates were strong and can be used to predict foliar concentrations and subsequent damage to roadside trees.

Frame and daughters directives for evaluating the ambient air quality have been adopted by the EU as a part of the new strategies for pollution prevention and control and environmental management. Therefore, the prediction of ozone concentration and the identification of episodes by modeling are fundamental for protecting and preventing the population and environment against the harmful effects of this species. Under this approach, ambient air quality (immission) data in three zones: A Guarda, Corrubedo and Verín (two coastal and one interior) of Galicia (NW Spain), were collected and evaluated using statistical tools. Punctual and functional background and standard levels of ozone and NOx in the three zones have been determined for detecting abnormal situations and identifying possible emission sources. With this aim, threshold values were established by defining confidence levels. Finally, ozone concentration has been forecasted by time series modeling. Descriptive and predictive models of ozone involving different parameters depending of the area considered have been developed. Satisfactory estimation of ozone concentration was obtained in the three cases with proved efficiency, since predictive values did not exceed the 95% confidence level.

Storm water detention devices collect runoff from impermeable catchments. They provide flow attenuation as well as storage capacity, and rely on natural self-purification processes such as sedimentation, filtration and microbial degradation. The aim was to assess the performance of an experimental combined planted gravel filter, storm water detention and infiltration tank system treating runoff from a car park and its access road. Flows were modeled with the US EPA Storm Water Management Model. An overall water balance of the system was compiled, demonstrating that 50% of the rainfall volume escaped the system as evaporation, whereas, of the remaining 50%, approximately two thirds were infiltrated and one third was discharged into the sewer system. These findings illustrated the importance of evaporation in source control, and showed that infiltration can be applied successfully even on man-made urban soils with low permeability. The assessment of the system's hydrological efficiency indicated mean lag times of 1.84 and 10.6 h for the gravel filter and the entire system, respectively. Mean flow volume reductions of 70% and mean peak flow reductions of 90% were achieved compared to conventional drainage. The assessment of the pollutant removal efficiency resulted in promising removal efficiencies for biochemical oxygen demand (77%), suspended solids (83%), nitrate-nitrogen (32%) and ortho-phosphate-phosphorus (47%). The most important removal processes were identified as biological degradation (predominantly within the gravel ditch), sedimentation and infiltration.

This study was initiated to explore the effects of ozone (O₃) exposure on potted wheat roots and soil microbial community function. Three treatments were performed: (1) Air with daily averaged O₃ concentration of 4-10 ppb (control situation, CK), (2) Air plus 8 h averaged O₃ concentration of 76.1 ppb (O₃-1), and (3) Air plus 8 h averaged O₃ concentration of 118.8 ppb (O₃-2). In treatments with elevated O₃ concentration (O₃-1 and O₃-2), the root and shoot biomass were reduced by 25% and 18%, respectively, compared to the control treatment (CK). On the other hand, root activity was significantly reduced by 58% and 90.8% in the O₃-1 and O₃-2 treatments, respectively, compared to CK. The soil microbial biomass was significantly reduced only in the highest O₃ concentration (O₃-2 treatment) in the rhizosphere soil. Soil microbial community composition was assessed under O₃ stress based on the changes in the sole carbon source utilization profiles of soil microbial communities using the Biolog[trade mark sign] system. Principal component analysis showed that there was significant discrimination in the sole-carbon source utilization pattern of soil microbial communities among the O₃ treatments in rhizosphere soil; however, there was none in the bulk soil. In rhizosphere soil, the functional richness of the soil microbial community was reduced by 27% and 38% in O₃-1 and O₃-2 treatments, respectively, compared to CK. O₃-2 treatment remarkably decreased the Shannon diversity index of soil microbial community function in rhizosphere soil, but the O₃-1 treatment did not. In the dominant microorganisms using carbon sources of carbohydrates and amino acids groups were significantly reduced by an elevated O₃ concentration in the rhizosphere soil. Our study shows that the elevated ozone levels may alter microbial community function in rhizosphere soil but not in the bulk soil. Hence, this suggests that O₃ effects on soil microbes are caused by O₃ detriments on the plant, but not by the O₃ direct effects on the soil microbes.

Automobile traffic pollutes roadside environments with a range of contaminants. In this study, we investigate the distribution patterns of different contaminant classes in topsoils across a highway-forest interface north-east of Vienna, Austria, in order to assess spatial pollutant distribution and evaluate the filtering effect of roadside forests. We collected soil samples along transects perpendicular to the highway, and analyzed the soils for road salt residues (Na), total and mobile heavy metals (Pb, Cd, Cu, Zn, Ni, Cr) as well as polycyclic aromatic hydrocarbons (PAHs). Roadside soil pollution was highly heterogeneous. All contaminants followed an exponential-like decrease with distance from the road, reaching background levels at 5 to 10 m from the road curb. Traffic-born heavy metals in the immediate roadside zone tended to be more mobile than heavy metals of predominantly geogenic origin at greater distances from the road; the presence of road salt residues could have contributed to the elevated heavy metal mobility near the road. The forest vegetation acted as filter for PAHs shown by a sharp concentration increase at the forest edge. PAHs are likely transported with airborne soot particles that are scavenged by the wax-coated coniferous needles at our study site.

This study examines the relationship between dissolved inorganic nitrogen (DIN: NH₄ ⁺ + NO₂ ⁻ + NO₃ ⁻) and dissolved organic nitrogen (DON) in river water and groundwater in an agriculturally-dominated catchment in south-east Spain, and estimates the contribution of DON to the total dissolved nitrogen (TDN) concentrations. The studied aquifer-dependent river system consists of Quaternary alluvial sediments deposited by the Guadalquivir River and its tributaries, with both river water and groundwater in the catchment being aerobic. DON is the predominant form of nitrogen in river water (72-97% of the TDN), whereas its proportion to TDN varies considerably in groundwater (<1-99%). A seasonal pattern in the concentration of dissolved nitrate in river water was observed, whereas DON concentrations showed no significant change during the study period. The export of DON from the Guadalquivir River is approximately 2 kg N ha⁻¹ year⁻¹ and is an order of magnitude higher than the export of DON from pristine catchments. Dissolved nitrate concentrations in groundwater were slightly higher in winter and DON concentrations were significantly lower (p < 0.05) in summer. It is found that agricultural soils constitute the main storage of organic nitrogen in the catchment with a steady leaching of high DON concentrations into the alluvial aquifer system (mean value 19.1 mg N L⁻¹), and so indicating that DON should not be overlooked in the nitrogen budgets of agriculturally-dominated catchments.

The Litavka River (length 56 km, watershed area 630 km², average flow at the outlet to the Berounka River 2.57 m³ s⁻¹) drains the historical mining, ore processing, and smelting region of Příbram. This Ag-Pb-Zn±Sb ore district (production from the thirteenth century to 1978, locally to 1980) is known for extensive heavy metal contamination. Recent contamination of the Litavka River system is mostly related to the erosion of contaminated soils and fluvial floodplains sediments, especially from a low-gradient river section located immediately below the ore district, where the fine-grained floodplain sediments are from 1.0 to 1.7 m thick. Radiocarbon accelerator mass spectrometry dating of charcoal fragments separated from one floodplain profile showed calibrated ¹⁴C age in the range AD 1220-1284 at a depth of 1.2 m below the surface, while depths of 0.4 and 0.8 m yielded ages in the range AD 1680-1939. Formation of this floodplain was related to disturbance of the river equilibrium resulting from deforestation and the influx of fine-grained material from ore processing, including historical failures of settling ponds. Fluxes of heavy metals during flood events in the Litavka River were studied 35 km downstream below the ore district. Metals are transported here mostly (more than 99% for Pb) in the form of suspended particulate matter (SPM), which at the outlet of the Litavka River contains 2,016 mg kg⁻¹ Zn, 918 mg kg⁻¹ Pb, and 25.5 mg kg⁻¹ Cd on average. During a snowmelt-related minor flood event between March 25 and 29, 2006 (peak flow 36.6 m³ s⁻¹), the river transported 2,400 tonnes of SPM during 4 days, containing 74 kg of Cd, 2,954 kg of Pb, and 5,811 kg of Zn. During larger floods (water flows above 55 m³ s⁻¹ have occurred here 27 times during the last 77 years), the contamination is more diluted by material eroded in the floodplain along the middle and lower river course.

To evaluate the phytoremediation capability of some poplar and willow clones a hydroponic screening for cadmium tolerance, accumulation and translocation was performed. Rooted cuttings were exposed for 3 weeks to 50 μM cadmium sulphate in a growth chamber and morpho-physiological parameters and cadmium content distribution in various parts of the plant were evaluated. Total leaf area and root characteristics in clones and species were affected by cadmium treatment in different ways. Poplar clones showed a remarkable variability whereas willow clones were observed to be more homogeneous in cadmium accumulation and distribution. This behaviour was further confirmed by the calculation of the bio-concentration factor (BCF) and the translocation factor (Tf). Mean values of all the clones of the two Salicaceae species showed that willows had a far greater ability to tolerate cadmium than poplars, as indicated by the tolerance index (Ti), calculated on the dry weight of roots and shoots of plants. As far as the mean values of Tf was concerned, the capacity of willows to translocate was double that of poplars. On the contrary, the mean values of total BCF in poplar clones was far higher with respect to those in willows. The implications of these results in the selection of Salicaceae clones for phytoremediation purposes were discussed.

Natural lignite from South Moravia was tested for the sorption of fluoride anion in concentration range from 5·10⁻⁵ to 8·10⁻⁴ mol/l. The lignite removes majority of fluorides and only about 13% of sorption is reversible upon leaching in pure water. Sorption data can be fitted by both Freundlich and Langmuir equations and both isotherms indicate presence of two principal sorption sites or steps. The sorption is fast, at least 90% of final sorbed amount is removed during the first 10 min but kinetic data show a complex pattern with temporary increase of fluoride concentration. This is attributed to complexity of lignite-water interactions, lignite soaking and swelling in aqueous media. Foreign ions and pH showed only slight influence on the sorbed amount. Natural lignite can be considered as a potential low-cost defluoridation agent that is effective at various solution chemistries and also at low, but still over-limit, fluoride concentrations.

This paper examines the historical change in the pH of natural rainwater due to increased atmospheric CO₂ from 1800 until 2007, giving predicted change in 2100. During 1800-2007, the rainwater pH at 25°C and 1 atm is calculated to decrease by 0.06 units, from 5.68 to 5.62. In 2100, the predicted rainwater pH is calculated at 5.49 using the projected pCO₂ (700 ppmv; IS92a) at 25°C and 1 atm. Equilibrium calculations were made in an attempt to elucidate the calcium carbonate (calcite) dissolution by rainwater. From 1800 to 2007, the dissolution of calcite with pCO₂ of those time at 25°C and 1 atm increase the dissolved calcium concentration from 466 to 516 μmol kg⁻¹. This value is calculated to reach 633 μmol kg⁻¹ in the year 2100. Rainwater is found to become more acidic with decreasing temperature. In the year 2007 (pCO₂ = 384 ppmv), a total difference of 0.08 units in rainwater pH is calculated between areas at 0°C and 30°C. The equilibrium pH with respect to calcite was found to increase with decreasing temperature. At lower temperatures, rainwater pH is found to decrease, whilst CaCO₃ dissolution increases. Limestone landmarks and buildings might be affected through the dissolution of calcium carbonate by rainwater acidification. The effects of rainwater acidification on overall chemical weathering may result in influences on agriculture, forestry, landslides and flooding.