A groundwater flow and mass transport model simulated the remediation capability of non-pumped wells with filter media placed in backfilled trenches in homogeneous and heterogeneous aquifers. For each of five homogeneous and heterogeneous aquifer settings, the model identified a base configuration of wells for a backfill hydraulic conductivity equal to the mean of the aquifer (1.5 m/d). Base configurations comprised the least number of wells necessary to contain and remove a contaminant plume. For each setting, the model also simulated base configurations with backfill hydraulic conductivity one and two orders of magnitude lower and one and two orders of magnitude higher than the mean of the aquifer. In general, backfill with a hydraulic conductivity equal to the mean of the aquifer, or slightly higher, outperformed other scenarios.

Suspended particles in water are a major concern in global pollution management. They affect the appreciation of water due to clarity, photosynthesis, and poor oxygen environment rendering water unsuitable for aquatic animals. Some suspended materials contain functional groups capable of forming complex compounds with metals making them available for poisoning. Such material promotes the growth of bacteria and fouling that give rise to unpleasant taste and odor of the water and thus requires removal. Removal of suspended solids is normally achieved through sedimentation or filtration. However, some suspended colloidal particles are very stable in water and cannot settle while others are able to pass through the filter due to small size, hence difficult to remove. This study investigated the use of triethanolamine-modified maize tassels to form a flocculent for their removal. The modified maize tassels were characterized using Fourier transform infrared (FTIR), and it was found that the triethanolamine was anchored within the cellulose structure of the maize tassels. Clarification parameters such as settling time, reagent dosage, and pH were investigated. The best clarification was at a pH of 6.0 with clearance being less than in 30 min. The optimal flocculent dosage was found to be 3.5 ml of the material, showing that the material has a potential of enhancing clarity in polluted water.

The aim of this work is to assess the occurrence of Polycyclic aromatic hydrocarbons (PAHs) in the Tisza River and its main Romanian tributaries (Vişeu River and Iza River) and to establish the origin (pyrogenic/petrogenic) of pollution sources. Fifteen PAHs were investigated in surface water and sediment samples collected from three selected sampling point. The target compounds were isolated from the matrices by solid phase extraction for water samples and by ultrasound-assisted extraction for the sediment samples, respectively. The quantification of the target compounds was performed by HPLC coupled with a fluorescence detector. PAH diagnostic ratios, as the abundance ratio of 2–3 ring hydrocarbons to 4–6 ring hydrocarbons (LMW/HMW), ANT/(ANT + PHE), FLT/(FLT + PYR), B[a]A/(B[a]A + CHR), and IND/(IND+ B[g,h,i]P) were used as a tool for identification and assessment of the pollution emission sources. The results of the study showed that in the studied area, the total concentrations of PAHs detected in water samples ranged from 1.22 to 260.26 ng L⁻¹, while those in sediment samples varied from 4.94 to 10.62 μg kg⁻¹. Regarding the PAH pattern, mixed sources of pollution (pyrogenic and petrogenic) occur in both water and sediment samples. Thus, leaks of petroleum products and biomass, coal, and petroleum combustion are the main sources of pollution identified into the studied area.

Bosten Lake, a typical rump lake in an oasis in northwest China, was chosen to evaluate the distribution, sources, pollution status, and potential ecological risk of heavy metals. Sediment samples were collected from the lake, and results showed that the values of the eight heavy metals all fell within the Second Soil National Standard, while the average and maximum values of the metals were higher than the background values of the study. Multivariate statistical analysis showed that sediment concentrations of Cd, Pb, Hg, and Zn were mainly influenced by man sources. In comparison, Cu, Ni, Cr, and As were primarily natural in origin. Enrichment factor analysis (EF) and the geo-accumulation index evaluation method (I gₑₒ) showed that Cd, Hg, and Pb fell under low and partial serious pollution levels, while Zn, As, Cr, Ni, and Cu mainly were characterized under no pollution and low pollution levels. The potential ecological hazards index (RI) showed that among the eight heavy metals, Pb, Hg, and Cd posed the highest potential ecological risk, with potential ecological hazards indices (RI) of 29.06, 27.71, and 21.54 %, respectively. These findings demonstrated that recent economic development in the area of the basin has led to heavy metal accumulation in the surface sediments of the lake.

ANT is a commonly occurring polycyclic aromatic hydrocarbon (PAH) in natural eutrophic waters where Microcystis blooms break out usually. In this study, effects of ANT at different concentrations (0.02, 0.06, 0.18, 0.54, and 1.62 μg/mL) on the growth, microcystin-LR (MC-LR) production, and expression of three key mcy genes in Microcystis aeruginosa were investigated. The results showed that all the tested concentrations of ANT inhibited M. aeruginosa growth significantly except 0.02 μg/mL ANT in the early stage of the experiment. In the culture media, initially applied ANT concentrations decreased significantly after 3 days of incubation. ANT stimulated MC-LR production in a concentration-dependent manner. After exposure to ANT for 1 day, the expression of mcyB gene was inhibited and the inhibitory effects increased with ANT concentrations. ANT at higher concentrations (above 0.02 μg/mL) stimulated gene expression of mcyD (P < 0.05) and mcyH (P < 0.01) significantly, and 0.02 μg/mL of ANT inhibited their expression significantly (P < 0.01). With increasing culture time, 0.18 μg/mL of ANT inhibited mcyB gene expression first and then stimulated it while gene expressions of mcyD and mcyH were stimulated throughout the experiment. Our results suggested that ANT in natural waters could affect not only Microcystis growth but also MC production via modifying mcy gene expressions.

Synthesis parameters of nano manganese oxide (NMO) were tuned in order to maximize Cs and Co sorption efficiencies. The prepared oxide was characterized using various techniques including x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), SEM, and surface area analyzer. The sorption characteristics with respect to uptake of Cs, Co, and Pb were evaluated. An α − phase nano manganese oxide with a surface area of 165 m² g⁻¹ was synthesized. Maximum adsorption capacities were 230 mg g⁻¹ for Pb²⁺, 73 mg g⁻¹ for Cs⁺, and 26 mg g⁻¹ for Co²⁺. The intra-particle diffusion was the rate-limiting step in the case of Pb²⁺, whereas both intra-particle diffusion and film diffusion contribute to the rate-determining step in the adsorption process in the case of Cs⁺ and Co²⁺. FT-IR analyses reveled that Cs⁺ and Co²⁺ coordinated to vacancy sites of NMO as inner-sphere complexes, while Pb²⁺ formed bidentate corner-sharing complexes. NMO had high affinity for Pb²⁺ but was also effective for sorption of Cs⁺ and Co²⁺ over a wide pH range, even in the presence of Na⁺. HCl (0.5 mol L⁻¹) solution could regenerate the adsorbent successfully, and the NMO could be efficiently reused with lower production of residues. Thus, the prepared NMO can be efficiently used in wastewater treatment in terms of high adsorption capacity, easy availability, and low cost.

The mass spectrometric analysis of the impact of sulfur dioxide and dust emission on carbon and oxygen stable isotopic compositions of glucose hydrolysed from α-cellulose samples extracted from Scots pine growing in the vicinity of “Huta Katowice” steelworks was the main aim of this study. The annual rings covered the time span from 1975 to 2012 AD. The relationships between climatic conditions, sulfur dioxide, and industrial dust emission and oxygen and carbon isotopic compositions were analyzed using correlation function methods. This study shows the first analysis of carbon and oxygen stable isotopes in glucose as the bio-indicators of CO₂, sulfur dioxide, and industrial dust emission. The anticoincidence trend of δ¹⁸O and δ¹³C and dust and sulfur dioxide confirms that the decreases of dust and sulfur dioxide industrial emission increase δ¹⁸O and δ¹³C values in glucose.

Various inorganic and organic pollutants in industrial soils may adversely affect soil microorganisms and terrestrial ecosystem functioning. The aim of the study was to explore the relationship between the microbial activity, microbial biomass, and functional diversity of soil bacteria and the metals and total petroleum hydrocarbons (TPHs) in the Upper Silesian Industrial Region (Poland). We collected soil samples in pine-dominated forest stands and analyzed them according to a range of soil physicochemical properties, including metal content (cadmium, lead, and zinc) and TPH content. Metal concentrations were normalized to their toxicity to soil microorganisms and integrated in a toxicity index (TI). Soil microbial activity measured as soil respiration rate, microbial biomass measured as substrate-induced respiration rate, and the bacterial catabolic activity (area under the curve, AUC) assessed using Biolog® ECO plates were negatively related to TPH pollution as shown in multiple regressions. The canonical correspondence analysis (CCA) showed that both TPH and TI affected the community-level physiological profiles (CLPPs) of soil bacteria and the pollutants’ effects were much stronger than the effects of other soil properties, including nutrient content.

Hydrologically controlled moist-soil impoundment wetlands provide critical habitat for high densities of migratory bird populations. Nutrients exported from heavily used impoundments by prescribed seasonal drawdown of surface water may contribute to the eutrophication of aquatic ecosystems. To investigate the relative importance of nutrient export from managed impoundment habitats, we conducted a field study at Mattamuskeet National Wildlife Refuge in North Carolina, USA, which contains 1545 ha of impoundments that drain into hypereutrophic Lake Mattamuskeet. We found that prescribed hydrologic drawdowns of an impoundment exported roughly the same amount of nitrogen (N) as adjacent fertilized agricultural fields on a per-area basis and contributed approximately one fifth of total N load to Lake Mattamuskeet. The prescribed drawdown regime, designed to maximize waterfowl production in impoundments, may be exacerbating the degradation of habitat quality in the downstream lake as an unintended consequence. Few studies of wetland N dynamics have targeted impoundments managed to provide wildlife habitat, but a similar phenomenon may occur in some of the 36,000 ha of similarly managed moist-soil impoundments on National Wildlife Refuges in the southeastern USA, especially those hosting dense concentrations of waterfowl. We suggest an earlier seasonal drawdown could potentially mitigate impoundment N pollution and estimate it could reduce N export from our study impoundment by more than 70 %.

Co-digestion of swine manure and crude glycerine from biodiesel production has been successfully attempted by many authors reporting substantial increments in biogas production. However, the effectiveness of this approach has been questioned recently. The addition of glycerol may cause an improvement in biogas production but at the expense of disturbing the degradation of manure. In the present paper, the organic transformations undergone in the anaerobic digestion of pig manure at increasing amounts of glycerine (2–8 % (v/v)) were analysed using spectroscopy techniques (Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H NMR)). An increase in biogas production was observed with the addition of glycerine up to 8 %, resulting in a volumetric production of methane per litre of reactor (Lr) of 1.4 L CH₄/Lr d. However, the subsequent failure of the system was observed at this glycerine content due to the inhibitory effect caused by high H₂S concentration and foam formation. FTIR and ¹H NMR analysis performed on digestate samples showed that the addition of the co-substrate also caused the preferential degradation of glycerine and accumulation of proteins and aliphatic compounds. A post-stabilisation stage was necessary to complete the degradation process. Modifications in organic matter continued under this last stage although in the previous digestion period, a competition for substrate between sulphate reducing bacteria and methanogens was observed.