Biosolids are a source of recycled organic matter and nutrients. To evaluate the impact of biosolids application (1984–2008) on soil quality, composite soils (Genesee silt loam, fine loamy, mixed, nonacid, and mesic typic udifluvent) were randomly sampled at geo-referenced sites from 0 (control), 2, 5, and 25 years of lime-stabilized anaerobically digested biosolid-applied fields. Results showed that microbial biomass C (Cₘᵢc), N (Nₘᵢc), and P (Pₘᵢc) contents were significantly higher at both depths of the 5 and 25 years of biosolid-applied fields compared to the control. Biosolid application significantly enlarged the biologically labile C (Cₘᵢc over total organic C, Cₘᵢc:Cₒᵣg) and N (Nₘᵢc over total N, Nₘᵢc:TN) pools with an associated decrease in metabolic C loss (20–53 %) by specific maintenance respiration (qCO₂) relative to the control. The Cₒᵣg, active (AC) and soluble C (SC), TN and reactive N (RN), and reactive P (RP) contents were significantly higher in the long-term biosolid-applied fields than in the control. However, there was an indication of leaching of SC, RN, and RP between depths. Years of biosolid application significantly increased soil moisture content (θ ᵥ at −0.03 MPa) by 20–40 %, macroaggregate stability (MaA) by 2–44 %, and mean weight diameter (MWD) of aggregates by 7–51 %, respectively. Consequently, there was a decrease in soil bulk density (ρ b) and microaggregate stability (MiA) at both depths. Results confirmed that biosolids application at rates recommended is a viable management option to improve soil quality for crop production. However, long-term and repeated biosolid applications above the recommended agronomic N and P rates may be responsible for accumulation and consequent leaching and runoff of SC, RN, and RP to cause groundwater and surface water pollution with environmental consequences.

In situ burning is a method by which oil is burned at a spill site under controlled conditions, and this method is subject to increased interest due to its applicability in the Arctic. This paper reviews the literature regarding the characterization and environmental effects of burn residues in Arctic waters. The results of a systematic literature search indicate that only a very limited number of studies have arctic pertinence. From the review, it is also indicated that the properties and composition of the residues depend on the efficiency of the burning and the oil type. Furthermore, the studies within the frame of the literature search reach consensus that in situ burning may increase the concentrations of large poly-aromatic hydrocarbons (PAHs; high ring number) while reducing small PAHs (low ring number). There are very few toxicity studies of burn residues on aquatic and arctic organisms, and to enhance the knowledge base, more organisms as well as oil types must be studied. Furthermore, there is a lack of studies investigating the potential effect of sinking burn residues on benthic organism and the smothering effects of the more viscous burn residues on birds and other organisms related to the sea surface. More knowledge regarding environmental fate and effect of residues is crucial to complete a robust net environmental benefit analysis prior to an oil spill response operation in arctic waters.

The objective of this study was to investigate the chemisorption mechanisms of Cu(II) on alcohol functionalized carbon nanotubes (OH-CNT) compared to granulated activated carbon (F-400). Two different sizes of OH-CNT were used on both adsorption isotherm experiments and continuous-flow fixed-bed columns. The experiments were conducted as a function of adsorbent type with fixed bed height (5 cm), fixed flow rate (0.035 mL/min), and one initial Cu(II) concentration (10 mg/L) at pH 5.1 and room temperature. Isotherm curves follow Freundlich model with better adsorption capacity for OH-CNT (6.3 and 15.7 mg/g) compared to F-400 (6.0 mg/g). Breakthrough curves for all adsorbents were typical, while OH-CNT showed higher capacity to treat water per amount of adsorbent than F-400. After 5 days of desorption, there was very little Cu(II) leached from the OH-CNT column as compared to F-400 that slowly desorbed 85 % of Cu(II). These results indicated chemisorption process on OH-CNT with low residual release of Cu(II) from adsorbent after reaching saturation. A systematic correlation method using converted FTIR absorbance curves (first derivative analysis) of as-received and hybrid OH-CNT identified new peaks on the spectra for Cu(II) chemisorbed on CNT surface, showing that Cu(II) target acidic functional groups during adsorption.

Long-term impacts of acidic deposition on the Great Smoky Mountains National Park (GRSM) include elevated inputs of sulfate, nitrate, and ammonium; the depletion of available nutrient cations from soil; and acidification of high-elevation streams. Critical loads and target loads (CLs/TLs) are useful tools to help guide future air quality management. We evaluated past and potential future effects of nitrate and sulfate deposition for 12 watersheds in the GRSM, USA, using the hydrochemical model, photosynthesis evapotranspiration biogeochemical (PnET-BGC). Two of the streams studied were listed by the state of Tennessee as impaired due to low stream pH. We reconstructed historical meteorological, atmospheric deposition, and land disturbance data for study watersheds for the period 1850 to present for model hindcasts. As future emissions are expected to decline, the model was run under a range of future scenarios from 2008 to 2200 of decreases in sulfate, nitrate, and ammonium and combinations of sulfate and nitrate deposition to estimate CLs and TLs of how watersheds might respond to emission control strategies. Model simulations of stream chemistry generally agreed with long-term (>10 years) observations. Model hindcasts indicate that watersheds in the GRSM are inherently sensitive to acidic deposition. Simulated mean projected stream ANC of 71 μeq/L (range 32 to 107 μeq/L) prior to industrial development (~1850) decreases in response to historical acidic deposition to 33 μeq/L (−13 to 88 μeq/L) in 2007. Future model projections show that decreases in sulfate deposition result in smaller increases in stream ANC compared with equivalent decreases in nitrate deposition; simultaneous controls on nitrate and sulfate deposition are more effective in ANC increases than individual control of nitrate or sulfate. Although there are no current programs in the USA to control ammonia emissions, model simulations suggest that decreases in ammonium deposition could also help mitigate acidification to a greater extent than equivalent controls on nitrate deposition.

Wastewater from textile industry contains a number of pollutants which are hazardous in nature. The direct discharge of the wastewater into the environment affects its ecological status by causing various undesirable changes. As environmental fortification becomes a global anxiety, industries are finding novel solutions for mounting low-cost and environmental-friendly technologies for the dye removal from the waste. The presence of the dyes hinders sunlight penetration and disturbs the ecosystem of water. However, the treatment of wastewater with biodegradable polymer attains a vital importance as they are environmental friendly. The main objective of the work was to make an effort to develop a feasible process for the removal of dyes/color from the textile wastewater by using potato starch, which is a plant-based bio-polymer. A three-level, full-factorial design was selected, and experiments were conducted using a jar test apparatus. The main effects and interactions of dosage, pH, and temperature on the percentage color removal were analyzed. Reduction in color was analyzed using UV-2800 spectrophotometer. A three-way significant interaction was observed. However, dosage is found to be the most important parameter for dye removal using potato starch.

Continuous use of recycled water (treated sewage effluent) over a long period of time may lead to the accumulation of salt in the root zone soil. This is due to the relatively higher levels of salt content in the recycled water compared to surface water. In this study, a laboratory column study was carried out to validate the HYDRUS 1D model under no rain condition. During the validation, the relative error and the % bias between observed and simulated soil water electrical conductivity (ECSW) were found to be low and varied in a range of 5–10 and 5–6 %, respectively. The validated model was then used to predict long-term (5 years) salt accumulation under drought conditions. The analysis of model predicted salt values showed a cyclical pattern of salt accumulation in the root zone, and this related to the variation in rainfall and evapotranspiration. The mean root zone ECSWin the 5th year was found to be within the highest salinity tolerance threshold for pasture (11.2 dS/m); however, the maximum root zone ECSWwas found to be about 63 % more than the threshold. Irrespective of seasons, in 5 years time, ECSWat the depth of 1.0 m increased from 3.0 to 7.0 dS/m, which may pose a salinity risk to the groundwater table if there is a perched water table at a depth <1 m below the field surface. One of the management options to minimise long-term salt accumulation was also examined. By reducing the salt in recycled water by 50 %, it was possible to keep the ECₛwwithin the recommended threshold values. Overall, the methodology developed in this study can be used to identify appropriate management options for sustainable recycled water irrigation.

A high concentration of dissolved gaseous mercury (DGM) was detected in post-desulfurized waste seawater, which was discharged from a coal-fired power plant equipped with a seawater desulfurization system and which was located in a coastal area. A large amount of DGM was converted from other forms of mercury during transformation processes, such as photo-reduction. The present study targeted the photo-reduction of mercury and the effects of various environmental parameters on DGM production in the post-desulfurized seawater discharged. The results suggested that the photo-reduction of mercury was significantly induced under UV radiation, especially with UVB. The particulate mercury on suspended solids was easily photo-reduced and considered as an important source of DGM. It was confirmed that the suspended solids in post-desulfurized seawater could enhance the reduction process of mercury under UV radiation. The pseudo-first-order rate constants of DGM production, which were determined through the concentration gradient and trial methods, were 1.39 × 10⁻³ min⁻¹and 1.45 × 10⁻³ min⁻¹, respectively. The values showed no significant difference and were both much higher than the reported results, indicating that the photo-reduction of mercury in post-desulfurized seawater deserved more attention. In addition, the initial mercury level was observed when mixing the post-desulfurized seawater with fresh seawater, and this suggested that a significant amount of initial mercury would be produced when the post-desulfurized seawater was discharged into the adjacent sea area and thus becomes another considerable source of DGM.

Palladium (Pd) is an emerging eco-toxic pollutant from vehicle catalytic converters, emitted worldwide for more than two decades. Nowadays, the spatial extent of Pd fallout is growing along roads, but its subsequent fate in neighboring terrestrial ecosystems has not been extensively addressed yet. Two sites representative of contrasted natural environments (field, forest) but located under similar ambient conditions were selected to isolate and analyze the specific impact of vehicular Pd, along highway A71, France. Pd impregnation was assessed along 200-m-long transects perpendicular to the highway. Contents were measured in soils, earthworms, plant communities of the right of way (ROW), and the neighboring field (crop weeds), as well as in a moss, and bramble and ivy leaves in the forest. The direct impact of Pd fallouts appears to be confined in the grassy verge of the highway: ROW soils ([Pd] = 52–65 ng g⁻¹), earthworms ([Pd] = 18–38 ng g⁻¹), and plant community ([Pd] = 10–23 ng g⁻¹). Pd footprint is pointed out by the accumulation index calculated for earthworms and plant communities even though transfer coefficients indicate the absence of bioaccumulation (TCs < 1). An indirect longer range transfer of Pd is identified, induced by hydric transport of organic matter.

Nanoparticles (NPs) are commonly used, and concerns about their possible adverse effects are being voiced as well. However, little is known about the fates of NPs released to the environment. The aim of the study was to (i) evaluate the ability of Sinapis alba and Lepidium sativum plants to take up platinum nanoparticles (Pt-NPs) and translocate them to aboveground organs, (ii) compare the accumulation efficiency of different forms of platinum and (iii) identify the forms in which platinum is stored in plant tissues. Plants were cultivated on medium supplemented with different concentrations of Pt-NPs and [Pt(NH₃)₄](NO₃)₂. Platinum content in plants was determined using inductively coupled plasma mass spectrometry. For the identification of the presence of Pt-NPs in plant tissues, gamma spectrometry following iron irradiation was applied. It was found that L. sativum and S. alba are tolerant to applied concentrations of Pt-NPs and have an ability to take up platinum from the medium and translocate it to aboveground organs. The highest concentration of platinum was observed in plant roots (reaching 8.7 g kg⁻¹for S. alba). We tentatively conclude that platinum is accumulated as nanoparticles. The obtained results suggest future application of plants for phytoremediation and recovery of noble metal nanoparticles.

Three commercial electrodes, Ta-Ir/TiO₂, Rh-Ir/TiO₂, and PbO₂/TiO₂, were used as electrochemical anodes, and their performance was evaluated by the electrochemical oxidation of ammonia at neutral pH in a continuous electrochemical quadrangular reactor. Based on the cyclic voltammetry scans and volt-ampere relation analysis, in direct oxidation, the oxygen evolution from H₂O₂decomposition was completely inhibited, and more•OH radicals could be then generated over PbO₂/TiO₂and in the presence of powder activated carbon (PAC). PbO₂/TiO₂can be indicated as an appropriate for the direct electrooxidation of ammonia in an unpacked bed reactor. While the efficiency for direct oxidation of ammonia was similar for the three anodes in a PAC packed reactor due to the presence of PAC could avoid short circuit and enhance electric efficiency. In indirect oxidation mediated by active free chlorine, Rh-Ir/TiO₂was the most effective in ammonia removal when chloride was present in the reaction system, and the disappeared ammonia was mainly transferred to N₂, and only a small part was converted into nitrate (there was no nitrite detected during the reaction). The results indicated that Rh-Ir/TiO₂had the highest oxidation capability for ammonia compared with Ta-Ir/TiO₂and PbO₂/TiO₂. Hence, Rh-Ir/TiO₂based on a PAC packed bed reactor provides an alternative for the treatment of ammonia wastewater with high chloride concentration.