High levels of marine salt deposition present in coastal areas have a relevant effect on road runoff characteristics. This study assesses this effect with the purpose of identifying the relationships between monitored water quality parameters and intrinsic site variables. To achieve this objective, an extensive monitoring program was conducted on a Portuguese coastal highway. The study included 30 rainfall events, in different weather, traffic, and salt deposition conditions. The evaluations of various water quality parameters were carried out in over 200 samples. In addition, the meteorological, hydrological, and traffic parameters were continuously measured. The salt deposition rates were determined by means of a wet candle device, which is an innovative feature of the monitoring program. The relation between road runoff pollutants and independent variables associated with weather, traffic, and salt deposition conditions was assessed. Significant correlations among pollutants were observed. A high salinity concentration and its influence on the road runoff were confirmed. Furthermore, the concentrations of the most relevant pollutants seemed to be very dependent on some meteorological variables, particularly the duration of the antecedent dry period prior to each rainfall event and the average wind speed.

In the present work, goethite (α-FeO(OH)) impregnated calcium alginate (Cal-Alg-Goe) beads were used to sorb the arsenic from groundwater without disturbing its physicochemical characteristics. Beads were formed by dropwise addition of homogenized mixer of goethite and 4 % sodium alginate solution in 0.2 M CaCl₂solution. Charge, size, and morphology of sorbents were characterized by using various techniques. The results of batch sorption experiments suggest that Cal-Alg-Goe beads are very effective for removal of arsenic in the pH range 3.0 to 7.5, and sorption was more than 95 % in the concentration range of 10–10,000 ng mL⁻¹. Beads were successfully tested for groundwater samples collected from areas having elevated levels of arsenic. Equilibrium sorption follows Langmuir isotherm model, and the maximum arsenic uptake calculated was 30.44 mg g⁻¹. The sorption kinetics could be explained by pseudo-first-order model, and the time needed for equilibrium was 24 h.

Cs is a common radionuclide present in nuclear wastes and released from nuclear power plant accidents. It is hard to be removed from water with traditional technology. The current study aimed at developing of efficient cost-effective adsorbent for removing Cs with modified MCM-41 with specific functional groups –SH. Mesoporous material MCM-41 was selected due to its large surface area and tunable pore structure. Functional –SH groups were grafted into the pores of MCM-41 to enhance its capability of selective adsorption of Cs from multi-element (Co, Sr) water solution. The adsorption results showed that the maximum adsorption capacity was 29.24 mg/g. Both Langmuir and Freundlich models described the adsorption processes of Cs, indicating co-existence of both monolayer and multilayer adsorption in the surface and inner pores of the materials. TEM, FTIR, and Raman spectroscopy analyses indicated that –SH groups were successfully bounded into the pores of MCM-41. The present study approved the surface functional modified MCM-41 which might be a good alternative candidate for cleaning up of radionuclide Cs from nuclear power plant accidents and relevant nuclear accident events.

The aim of the study was to estimate the influence of soil pH on the uptake of copper, zinc, and manganese by Valeriana officinalis. Preliminary studies involved soil analyses to determine acidity, organic matter content, and copper, zinc, and manganese total and bioavailable forms. The study involved atomic absorption spectrometry to determine the concentration of the elements, and mineral soil of pH = 5.1 was used in the study, as being typical for central Poland. The copper, zinc, and manganese contents were determined in plants grown in soils which had been modified to cover a wide range of pH values 3÷13. The intensity of germination was strongly pH dependent with the highest yield obtained in original, unmodified soil. Surprisingly, high soil alkalinity stimulated copper and manganese uptake while at the same time resulting in a decrease in zinc content.

In this study, two carbon materials [chicken manure biochar (CMB) and black carbon (BC)] were investigated for their effects on the reduction of hexavalent chromium [Cr(VI)] in two spiked [600 mg Cr(VI) kg⁻¹] and one tannery waste contaminated [454 mg Cr(VI) kg⁻¹] soils. In spiked soils, both the rate and the maximum extent of reduction of Cr(VI) to trivalent Cr [Cr(III)] were higher in the sandy loam than clay soil, which is attributed to the difference in the extent of Cr(VI) adsorption between the soils. The highest rate of Cr(VI) reduction was observed in BC-amended sandy loam soil, where it reduced 452 mg kg⁻¹ of Cr(VI), followed by clay soil (427 mg kg⁻¹) and tannery soil (345 mg kg⁻¹). X-ray photoelectron microscopy confirmed the presence of both Cr(VI) and Cr(III) species in BC within 24 h of addition of Cr(VI), which proved its high reduction capacity. The resultant Cr(III) species either adsorbs or precipitates in BC and CMB. The addition of carbon materials to the tannery soil was also effective in decreasing the phytotoxicity of Cr(VI) in mustard (Brassica juncea L.) plants. Therefore, it is concluded that the addition of carbon materials enhanced the reduction of Cr(VI) and the subsequent immobilization of Cr(III) in soils.

Electric arc furnace (EAF) dust and slag, materials which contain high metals in their composition, were improperly disposed in an industrial steel mill site between 1963 and 1999. Previous environmental investigations identified anomalous concentrations of metals in local groundwater but failed to relate these abnormalities to the disposed material or to natural geochemical processes. Aiming to identify the origin of such abnormalities, exploratory and spatial data analysis (EDA-SDA) method was applied on a hydrogeochemical data set obtained through 5 sampling campaigns in 32 groundwater monitoring wells installed upstream and downstream of the area impacted by the steel mill activities. Boxplot class-based and Eh vs. pH maps of physicochemical log-transformed data identified that wells located under the influence of EAF slag deposits in topographic hollows had lower Eh potential and increased electrical conductivity and pH, when compared to wells in the topographical nose of the surveyed area. Metal distribution maps showed that Al, Ca, K, Mg, Na, and Sr were consistently higher in topographic hollows while concentrations of Co, Cu, Cr, and Li were higher near the former steel-making plant, located in the topographical nose. Ba, Fe, Mn, and Zn, important indicators of EAF slag and dust, were observed in both topographic settings. Variable clustering was able to capture the relations among metals and thus validate the log-normalized data structure to be used into wells clustering. Clustering through the mclust algorithm carried out for two and three clusters allowed the distinction among localities that received an input of metals from dust or slag and those not influenced by either residue. This paper demonstrates that EDA-SDA is an effective method to identify areas under the influence of contamination from industrial activities from areas not affected by anthropogenic contamination.

This paper presents the efficacy of zero-valent iron nanoparticles (ZVINs), magnetic iron oxide nanoparticles (MINs), zero-valent iron nanoparticles/sugarcane bagasse (ZVIN-SB) composite and magnetic iron oxide nanoparticles/sugarcane bagasse (MIN-SB) composite in immobilizing chromium present in tannery sludge. The optimized values for the immobilization of chromium by the adsorbents were found to be 48 h, 100 g/kg and 7, respectively, for time, adsorbent dosage and pH. The maximum uptake capacity was found to be 429.75, 539.25, 587.25 and 625.8 mg/kg, respectively, for ZVIN, MIN, ZVIN-SB and MIN-SB. The desorption study of the unamended sludge and sludge amended by ZVIN, MIN, ZVIN-SB and MIN-SB was carried out with three different desorbing media (0.1 N HCL, DIW and 0.1 N NaOH). It was found that the cumulative concentration of leachate chromium was more in basic condition than in neutral and acidic conditions. In column studies, the concentration of leachate chromium attained 0 mg/L at 24, 15, 18 and 14 pore volumes, respectively, for the sludge amended by ZVIN, MIN, ZVIN-SB and MIN-SB. The experimental adsorption data fitted well with pseudo-first-order kinetics. The zero-order kinetics accurately predicted the experimental desorption capacity (q ₑ) of the sludge amended by ZVIN, MIN, ZVIN-SB and MIN-SB. The Fourier transform infrared spectroscopy (FTIR) analysis showed that the amine, carboxyl, iron compounds, etc. present in the adsorbents were the chief causes for the immobilization of chromium. The X-ray diffraction (XRD) analysis of the sludge showed the presence of trivalent chromium compounds at a higher concentration.

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are the two most important groups of pollutants associated with rail transport. Both have a serious negative impact on the natural environment, including human health and degradation of sensitive ecosystems. In our study, apart from qualitative and quantitative analysis of the main PAHs and heavy metals associated with rail, we tried to assess composition of specific compounds related to functional areas of railway infrastructure and to distinguish potential chemical markers which can be used for identification of pollution. Moreover, we evaluated the applicability of plants overgrowing railway infrastructure as bioindicators of rail-associated pollution. Though we confirmed that high amounts of PAHs and heavy metals in soil are characteristic for intensively used railway infrastructure, we found no typical pollution profiles for the differently used areas (i.e. platforms, sidings, cleaning bays). The major source of these contaminants is petroleum products used in conservation of railway infrastructure and rolling stock. As far as the use of plants overgrowing railway infrastructure as bioindicators of rail-associated pollution is concerned, it is rather limited, due to frequent application of herbicides for security and track stability reasons.

This paper proposes an extraction procedure for the speciation analysis of inorganic antimony in sediment samples using slurry sampling and hydride generation atomic absorption spectrometry. The optimization step of extraction of the species was performed employing a full two-level factorial design (2³) and a Box-Behnken matrix where the studied factors in both experiments were: extraction temperature, ultrasonic radiation time, and hydrochloric acid concentration. Using the optimized conditions, antimony species can be extracted in closed system using a 6.0 M hydrochloric acid solution at temperature of 70 °C and an ultrasonic radiation time of 20 min. The determination of antimony is performed in presence of 2.0 M hydrochloric acid solution using HG AAS by external calibration technique with limits of detection and quantification of 5.6 and 19.0 ng L⁻¹ and a precision expressed as relative standard deviation of 5.6 % for an antimony solution with concentration of 6.0 μg L⁻¹. The accuracy of the method was confirmed by analysis of two certified reference materials of sediments. For a sample mass of sediment of 0.20 g, the limits of detection and quantification obtained were 0.70 and 2.34 ng g⁻¹, respectively. During speciation analysis, antimony(III) is determined in presence of citrate, while total antimony is quantified after reduction of antimony(V) to antimony(III) using potassium iodide and ascorbic acid. The method was applied for analysis of six sediment samples collected in São Paulo Estuary (Bahia State, Brazil). The antimony contents obtained varied from 45.3 to 89.1 ng g⁻¹ for total antimony and of 17.7 to 31.4 ng g⁻¹ for antimony(III). These values are agreeing with other data reported by the literature for this element in uncontaminated sediment samples.

The feasibility of date seeds as a new low-cost natural adsorbent for the removal of dissolved organic carbon (DOC) from oily produced water was investigated. The aim of this study was to elucidate the mechanism associated with the removal of DOC and to find the best equilibrium isotherms and kinetic models for DOC removal in batch adsorption experiments. The effect of various physicochemical parameters such as initial DOC concentration (18.5–93.5 mg/L), solution pH (4–9), temperature (25–45 °C), and date seeds dosages (0.5–2.0 g) was evaluated. The equilibrium stage was attained after a contact time of 120 min. The maximum DOC removal was 82 % for 93.5 mg/L of DOC concentration. The equilibrium data were well represented by the Langmuir isotherm. The maximum monolayer adsorption capacity of date seeds was found to be 74.62 mg/g. The separation factor, R L, from the Langmuir equation and the Freundlich constant, n, indicated a favorable adsorption. The kinetic studies indicated that the adsorption process follows the pseudo-second-order kinetics. The adsorption of DOC is governed by both surface and pore diffusion. The results revealed that the DOC uptake decreases when temperature and pH increases. The adsorption process has been found exothermic in nature, and the thermodynamic parameters were determined. The Langmuir isotherm model equation was adopted to design a single-stage batch absorber for DOC adsorption onto date seeds. The study demonstrated that date seeds can be considered as a promising low-cost adsorbent for the removal of DOC from oily produced water.