In this study, polyaniline (PANi) was chemically synthesized with polyvinyl alcohol (PVA) to form PANi/PVA composites. Then, the composite was employed for adsorption of mercury from aqueous environment and a thorough comparison of PANi/PVA and PANi composites was made by conducting various experiments in different pH values, initial mercury concentrations, and contact time. The adsorption isotherms were also provided, and the effect of various water constituents was investigated. The results showed that both composites are considerably effective on removing mercury from aqueous environment. PANi and PANi/PVA removed around 92.7 and 90% of mercury at pH of 6. The solution pH also played an important role on adsorption efficiency, the optimum pH for the adsorption of mercury by PANi and PANi/PVA was determined as 5.5 and 6, respectively. Besides, the optimum contact time for both composites was calculated as 30 min and the efficiency of mercury removal was increased with a reduction in initial mercury concentration.

In order to investigate level and potential sources of polycyclic aromatic hydrocarbons (PAHs) in wheat fields affected by coal combustion in Henan and Shaanxi Provinces and to investigate distribution and transfer of PAHs in winter wheat grown in the areas, various tissues of the crop and the corresponding rhizosphere soils were collected during the harvest season of winter wheat. The mean concentrations of USEPA 15 priority PAHs (sum of the three- to six-ring PAHs) ranged from 486 to 1117 μg kg⁻¹ in the rhizosphere soils, indicating serious PAH contamination. Based on both the isomeric ratios of PAHs and a principal component analysis (PCA), the main sources of PAHs in the agricultural soils were from combustion of biomass, coal and petroleum, and petroleum. ∑₁₅PAHs were significantly (p < 0.001) higher in the roots (287–432 μg kg⁻¹) than those in aerial tissues (221–310 μg kg⁻¹). There were two decreasing gradients of PAH concentrations, one from roots, stems to leaves, and the other from glumes to grains. Regardless of sampling sites, most PAHs detected in the roots and in the aerial tissues were three-ring PAHs (acenaphthene, acenaphthylene, fluorene, phenanthrene, and anthracene) and the percentages of three-ring PAHs were much higher in the aerial tissues (72.5–82.7%) than in the roots (49.5–74.0%) and in the rhizosphere soils (36.3–65.7%). The distribution of PAHs with different ring numbers in the stems, leaves, and glumes was quite similar to each other but was significantly different from that of the roots and rhizosphere soils. Combined with significant results from partial correlation and linear regression models, the present study suggested that partial three- to four-ring PAHs in the aerial tissues are derived from root-soil uptake and that six-ring PAHs may come from the air-to-leaf pathway, although the quantity contribution of foliar uptake and root uptake was yet to be further studied.

Decline in global surface water quality around the world is closely linked to excess sediment and nutrient inputs. This study examined sediment and phosphorus fluxes in Aquia Creek, a fourth-order sub-watershed of the Chesapeake Bay located in Stafford, Virginia. The Revised Universal Soil Loss Equation (RUSLE), sediment delivery ratio (SDR), field sediment traps, bank erosion pins, and LIDAR data, combined with historical aerial images, were used in quantifying rill and inter-rill erosion from the basin, as well as internally generated sediments. Stream water and stream bank soils were analyzed for phosphorus. RUSLE/SDR modeling estimates a basin total sediment flux of 25,247 tons year⁻¹. The greatest calculated soil losses were in deciduous forests and cropland areas, whereas medium and high-intensity developed areas had the least soil loss. Cut-bank erosion ranged from 0.2 to 27.4 cm year⁻¹, and annual bank sediment fluxes were estimated at 1444 Mg, with a corresponding annual mass of phosphorous of 13,760 kg year⁻¹. The highest bank loss estimates were incurred along reaches draining urban areas. Stream water total phosphorous levels ranged from 0.054 μg g⁻¹ during low flows to 134.94 μg g⁻¹ during high discharge periods in autumn and spring. These results show that stormwater management practices in urban areas are limiting runoff water and soil contact, reducing surficial soil loss. However, the runoff acceleration due to expansion of impervious surfaces is progressively increasing the significance of intrinsic sediment and phosphorous sources by exacerbating stream bank erosion and resuspension of internally stored sediments.

In this study, the long-term effects of ultrafine tourmaline particles (UTPs) on the removal of nitrogen in wastewater, activated sludge viability and microbial population dynamics at low temperatures were investigated. Although there was no significant effect on the effluent concentrations of nitrogen after long-term exposure to 1 g/L UTPs at low temperatures, the oxidation rate of NH₄⁺-N and the accumulation rate of NO₂⁻-N increased and the formation rate of NO₃⁻-N decreased during the aerobic phase of sequencing batch reactors. However, long-term exposure to 1 g/L UTPs did not significantly affect the microbial community richness and the community diversity of activated sludge at low temperatures. The mechanism of tourmaline was studied by assessing the dominant functional species involved in biological nitrogen removal from wastewater. It was found that 1 g/L UTPs increased the removal rate of nitrogen by reducing the relative abundance of nitrite oxidizing bacteria and increasing the relative abundance of ammonia oxidizing bacteria after long-term operation at low temperatures.

Application of copper-based algaecide formulations is commonly conducted to control nuisance cyanobacterial blooms. Most field application scenarios have a rapid decline in external aqueous copper concentrations. Copper partitioned to algae can remain bound in external state, transition into the cell, or desorb back into solution. Understanding short-term fate of applied copper-based algaecides is critical in risk assessment for non-target species as well as achieving desired efficacy of target nuisance algae. This research assessed the ability of copper from different algaecide formulations to partition to Lyngbya wollei and the subsequent internalization and desorption of copper following cessation of the aqueous exposure. Following a 6-h exposure, there were no significant differences in total partitioned copper between copper sulfate and an ethanolamine chelated copper formulation (Captain® XTR). Four days after cessation of the aqueous copper exposure, all chelated copper and copper sulfate (except 2 mg Cu/L) exposures had significantly decreased adsorbed copper to L. wollei. However, chelated copper had significantly more internalized copper (P < 0.05) at the 0.5, 1, and 2 mg Cu/L treatments compared with the 6-h measurements and higher internalized copper than copper sulfate at the 2 and 4 mg Cu/L treatments. Average desorbed copper was lower in most chelated copper treatments compared with copper sulfate, although no statistically significant differences were measured between formulations. This information will allow water resource managers to select the most efficient algaecide formulation for desired algal control, with a better understanding of depuration potential, offsite movement, and risks to non-target organisms.

The increasing contamination of soils, sediments, and water with heavy metals through natural and industrial processes is a worldwide problem. Mining processes produce tons of material contaminated with radionuclides such as U and different heavy metals such as Cd, Ni, and Pb. U(VI) adsorbs strongly on bacteria, exhibiting pH-dependent adsorption behavior that is caused by a range of uranyl surface complexes on bacteria cell walls. The Amycolatopsis sp. K47 was isolated from Manisa Koprubasi Kasar open-cast uranium mine and identified for the first time. Using the batch adsorption method, the biosorption potential of this microbe was investigated by studying the effects of changes in pH (1–10), biomass dose (0.1–5 g/l), initial uranium metal concentration (5–200 mg/l), contact time (5–180 min), and temperature (20–60 °C). Interpretation of FTIR data obtained for both the uranium loaded and unloaded Amycolatopsis sp. K47 biomass showed the presence of carboxylic acid, hydroxyl, and amide functional groups that could interact with uranium ions. Scanning electron microscopy images demonstrated that uranium was intensely adsorbed on the microbial biomass surface. The sorption isotherms were investigated by analysis of the Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) models. The Langmuir isotherm model was found to show the best fit for the experimental data obtained. Furthermore, thermodynamic parameters, such as ΔH°, ΔS°, and ΔG°, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. The optimal experimental conditions were determined to be pH = 4, C₀ = 40 ppm, t = 150 min, temp. = 40 °C, and abs. dose = 1 g/l, and the corresponding U(VI) removal efficiency was about 97 ± 2%.

The photocatalytic mineralization efficiency of volatile organic compounds (VOCs) is determined by adsorption of reactants, separation of charge carriers, and reaction activity of catalyst surface. Herein, we provide a strategy to synthesize a novel catalyst, namely, PhPt-Micro, which is characterized by high adsorption ability, charge separation efficiency, and surface reaction activity. Toluene was chosen as the model VOC. The effects of photochemical deposition of Pt on the physical properties of microporous amorphous TiO₂ (Micro) and toluene mineralization were studied using N₂ adsorption/desorption, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, GC-flame ionization detection, and surface photovoltage spectroscopy (SPS) analyses. After photochemical treatment, the structure of Micro was optimized, and Pt nanoparticles were successfully deposited at the outlet of electrons on the catalyst surface. SPS result proved that the optimized structure enhanced the separation efficiency of charge carriers and the migration of photo-generated electrons to the PhPt-Micro surface. The quasi-equilibrium adsorption amount of toluene over PhPt-Micro was two times higher than that with commercial nano TiO₂ (P25). The micropores concentrated toluene on the catalyst surface and hindered intermediate desorption. The mineralization efficiency of toluene over PhPt-Micro was 2.4 and 5.9 times higher than those over Micro and P25, respectively.

This study reports the presence of the blaPER, sul1 and sul2 genes and class 1 integron inside an IncA/C plasmid with ~ 30 Kb in an isolate of Stenotrophomonas maltophilia. PER-producing Stenotrophomonas maltophilia was obtained from a soil sample cultivated with corn in Maringá City, Paraná State, Brazil. To the best of our knowledge, this is the first report in the world of blaPER gene in a bacterium isolated from soil and in a Stenotrophomonas maltophilia.

Silver nanoparticles (AgNPs) can enter the environment when released from products containing them. As AgNPs enter soil, they are often retained in the soil profile and/or leached to the groundwater. This research assessed the transport of AgNPs in their “particle form” through the soil profile using a series of columns. Three soil types were put into soil columns: LSH (loam with high organic matter (OM)), LSL (loam with low OM), and Sand (no OM). The results showed that AgNP transport and retention in soil as well as particle size changes are affected by soil organic matter (OM) and the cation exchange capacity (CEC) of soil. OM affected the transport and retention of AgNPs. This was evident in the LSH columns where the OM concentration was the highest and the AgNP content the lowest in the soil layers and in the effluent water. The highest transported AgNP content was detected in the Sand columns where OM was the lowest. CEC had an impact on the particle size of the AgNPs that were retained in the soil layers. This was clear in columns packed with high CEC-containing soils (LSL and LSH) where AgNP particle size decreased more substantially than in the columns packed with sand. However, the decrease in AgNP sizes in the effluent water was less than the decrease in particle size of AgNPs transported through but retained in the soil. This means that the AgNPs that reached the effluent were transported directly from the first layer through the soil macropores. This work highlights the ability to track AgNPs at low concentrations (50 μg kg⁻¹) and monitor the changes in particle size potential as the particles leach through soil all of which increases our knowledge about AgNP transport mechanisms in porous media.

Onsite wastewater treatment systems (OWTS) are an important part of the water infrastructure in the USA. Advanced OWTS are used instead of conventional OWTS to lower nitrogen (N) inputs to coastal ecosystems and groundwater sources used for drinking. Knowledge of the N load from OWTS helps identify drivers of excess N and develop strategies to lower N inputs. We used wastewater flow and effluent total N (TN) concentration to determine the mass N load from 42 advanced N-removal OWTS technologies (Orenco Advantex AX-20®, BioMicrobics MicroFAST®, SeptiTech D® series) and 5 conventional OWTS within the Rhode Island, USA, part of the Greater Narragansett Bay watershed. The median N load (g N/system/day) followed the order: conventional systems (31.1) > AX-20 (10.8) > FAST (10.1) > SeptiTech (9.6), and was positively correlated with flow. Results of a Monte Carlo simulation estimated the N load from the current distribution of conventional and advanced systems (105,833 systems total; Current scenario) to the watershed at 1,217,539 kg N/year. Compared to the Worse Case scenario (100% conventional OWTS), advanced OWTS currently prevent 53,898 kg N/year from entering the watershed. The per capita N load (kg N/capita/year) from OWTS under the current scenario is 4.68, and 1.47 for a local wastewater treatment plant (WTP) with biological N removal (BNR). Replacing 5150 conventional OWTS yearly with the most effective OWTS technology would result in a per capita N load from OWTS equivalent to that for a WTP with BNR after ~15 years, with a yearly cost of $174.24 per additional kilogram of N removed. Increasing the proportion of advanced OWTS that achieve the final effluent standard of 19 mg TN/L—through monitoring and recursive adjustment—would reduce the time and cost necessary to achieve parity with the WTP. Advanced N-removal OWTS are an important part of the water infrastructure that can lower N load to the Narragansett Bay watershed.