Polythene degradation leads to the production of various by-products depending upon the type of degradation process. The polythene degradation products (PEDP) in the culture supernatant of the two bacteria (Lysinibacillus fusiformis strain VASB14/WL and Bacillus cereus strain VASB1/TS) were analyzed with GC-MS technique. The major by-products in the PEDP in the culture supernatant of L. fusiformis strain VASB14/WL (1,2,3,4 tetra methyl benzene) and B. cereus strain VASB1/TS (1,2,3 trimethyl benzene, 1 ethyl 3,5-dimethyl benzene, 1,4 di methyl 2 ethyl benzene, and dibutyl phthalate) dissolved in diethyl ether were recorded. To assess the environmental applicability of polythene degradation using L. fusiformis strain VASB14/WL and B. cereus strain VASB1/TS at in vitro level. The effect of PEDP produced after 2 months of regular shaking at room temperature on both plants and animal system was studied. No significant decrease in the percent seed germination was recorded with the PEDP of both the bacteria. PEDP produced by L. fusiformis strain VASB14/WL did not report any significant change in germination index (GI) at 10 and 25 %, but least GI (39.66 ± 13.94) was documented at 50 % concentration of PEDP. Highest elongation inhibition rate (53.83 ± 15.71) of Sorghum was also recorded with L. fusiformis and at the same concentration.

Numerical experiments involving street canyons of varying aspect ratio with traffic-induced pollutants (PM₂.₅) and implanted trees of varying aspect ratio, leaf area index, leaf area density distribution, trunk height, tree-covered area, and tree planting pattern under different wind conditions were conducted using a computational fluid dynamics (CFD) model, ENVI-met. Various aspects of dispersion and deposition were investigated, which include the influence of various tree configurations and wind condition on dispersion within the street canyon, pollutant mass at the free stream layer and street canyon, and comparison between mass removal by surface (leaf) deposition and mass enhancement due to the presence of trees. Results revealed that concentration level was enhanced especially within pedestrian level in street canyons with trees relative to their tree-free counterparts. Additionally, we found a dependence of the magnitude of concentration increase (within pedestrian level) and decrease (above pedestrian level) due to tree configuration and wind condition. Furthermore, we realized that only ∼0.1–3 % of PM₂.₅ was dispersed to the free stream layer while a larger percentage (∼97 %) remained in the canyon, regardless of its aspect ratio, prevailing wind condition, and either tree-free or with tree (of various configuration). Lastly, results indicate that pollutant removal due to deposition on leaf surfaces is potentially sufficient to counterbalance the enhancement of PM₂.₅ by such trees under some tree planting scenarios and wind conditions

Removal of oil spillage from the environment is a global concern. Various methods, including the use of fibers as sorbents, have been developed for oil spill control. Oil palm empty fruit bunch (OPEFB) fiber is a plant biomass that may be acetylated by acetic anhydride using N-bromosuccinimide (NBS) as a catalyst; here, the extent of acetylation may be calculated in terms of weight percent gain (WPG). The modified fiber was used to remove Tapis and Arabian crude oils. The optimum time, temperature, and catalyst concentration were 4 h, 120 °C, and 3 %, respectively, and these parameters could achieve an 11.49 % increase in WPG. The optimized parameters improved the adsorption capacity of OPEFB fibers for crude oil removal. The acetylated OPEFB fibers were characterized by using Fourier transform infrared spectroscopy and field emission scanning electron microscopy to observe the functional groups available and morphology. Kinetic and isotherm studies were conducted using different contact times and oil/water ratios. The rate of oil sorption onto the OPEFB fibers can be adequately described by the pseudo-second-order equation. Adsorption studies revealed that adsorption of crude oil on treated OPEFB fiber could be best described by the Langmuir isotherm model.

The increasing frequency of extreme events in large rivers may affect not only their flow, but also their water quality. In the present study, spatial and temporal changes in fluvial physico-chemical variables were analyzed in a mega-river delta during two extreme hydrological years (La Niña-El Niño) and related to potential explanatory factors. Basic water variables were evaluated in situ at 13 points (distant 2–35 km from each other) in watercourses of the Delta Biosphere Reserve (890 km²) in the Lower Paraná River (Argentina) in nine surveys (October 2008–July 2010) without meteorological tides. Samples for laboratory analyses were collected from each main river. Multivariate tests by permutations were applied. The period studied was influenced by a drought, within a long period dominated by low flows combined with dry weather and wildfires, and a large (10 years of recurrence) and prolonged (7 months) flood. The hydrological phase, followed by the season and the hydrological year (according to the ENSO event) were the principal explanatory factors of the main water quality changes, whereas the drainage sub-basin and the fluvial environment (river or stream) were secondary explanatory factors. During the drought period, conductivity, turbidity, and associated variables (e.g., major ions, silicon, and iron concentrations) were maximal, whereas real color was minimal. In the overbanking flood phase, pH and dissolved oxygen concentration were minimal, whereas real color was maximal. Dissolved oxygen saturation was also low in the receding flood phase and total major ion load doubled after the arrival of the overbanking stage. The water quality of these watercourses may be affected by the combination of several influences, such as the Paraná River flow, the pulses with sediments and solutes from the Bermejo River, the export of the Delta floodplain properties mainly by the flood, the season, and the saline tributaries to the Lower Paraná River. The high influence of the hydrology of this large river on the Delta fluvial water quality emphasizes the relevance of changes in its flow regime in recent decades, such as the seasonality attenuation. Considering that the effects of extreme events differ among and within fluvial systems, specific ecohydrological evaluations and powerful appropriate statistics are key tools to gain knowledge on these systems and to provide bases for suitable management measures in a scenario of climate change and increasing human alterations and demands.

Activated carbon fiber (ACF) was used as a green catalyst to activate persulfate (PS) for oxidative decolorization of azo dye. ACF demonstrated a higher activity than activated carbon (AC) to activate PS to decolorize Orange G (OG). The decolorization efficiency of OG increased as ACF loading, PS dosage, and temperature increased. OG decolorization followed a pseudo first-order kinetics, and the activation energy was 40.902 kJ/mol. pH had no apparent effect on OG decolorization. Radical quenching experiments with various radical scavengers (e.g., alcohols, phenol) showed that radical-induced decolorization of OG took place on the surface of ACF, and both SO₄ ·⁻ and HO· were responsible for OG decolorization. The impact of inorganic salts was also evaluated because they are important compositions of dye wastewater. Cl⁻ and SO₄ ²⁻ exhibited a promoting effect on OG decolorization, and the accelerating rate increased with elevating dosage of ions. Addition of Cl⁻ and SO₄ ²⁻ could increase the adsorption of OG on ACF surface, thus favorable for OG decolorization caused by the surface-bound SO₄ ·⁻ and HO·. Conversely, HCO₃ ⁻ and humic acid (HA) slightly inhibited OG decolorization. The azo band and naphthalene ring on OG were remarkably destructed to other intermediates and finally mineralized to CO₂ and H₂O.

Sediment bacterial communities are sensitive to water conditions in river ecosystems. The objective of this study was to compare the influences of different pollution sources, including urban areas, wastewater treatment plants (WWTPs), suburban areas, and agricultural areas, on sediment bacterial communities along a typical tributary of Taihu Lake, China. The dominant composition of the sediment bacterial community was determined using a combination of terminal restriction fragment length polymorphism (T-RFLP) and a 16S rRNA clone library. The results showed that the sediment bacterial communities were distinctly affected by the four pollution sources. Alphaproteobacteria, Betaproteobacteria, and Actinobacteria (>50 % in total) were the predominant bacterial taxa across the sediment samples. Apart from those, the sediment bacterial community composition (BCC) affected by WWTP effluent was subsequently dominated by Nitrospira (12.4 %) and Bacteroidetes (11.5 %), agriculture was dominated by Firmicutes (13.2 %) and Deltaproteobacteria (7.2 %), while urban and suburban were dominated by Bacteroidetes (7.6 and 7.9 %, respectively) and Deltaproteobacteria (7.9 and 7.6 %, respectively). Cluster analysis indicated that the BCC affected by WWTP effluent was distinct from the BCC in urban, suburban, and agricultural areas. In addition, the bacterial community richness and evenness affected by WWTP effluent were much less than those by the other pollution sources. Redundancy analysis (RDA) indicated that the variation in BCC across the sediment samples was significantly associated with ammonium (17 %), organic matter (12 %), and cadmium (3 %) (p < 0.01). Overall, the results indicated that the four different pollution sources (WWTP, urban, suburban, and agriculture) have dissimilar impacts on the sediment BCC in the tributary of Taihu Lake, while WWTPs exhibited the greatest potential to lead to biotic homogenization in river sediments.

Nutrient recovery from human urine is a promising pretreatment of domestic wastewater and provides a sustainable recyclability of N and P. In this study, batch experiments were conducted to identify the characteristics of natural loess (NL) for the adsorption and recovery of ammonium and phosphate from hydrolysis urine (HU). The adsorption mechanisms, the adsorption kinetics and isotherms, as well as the major influencing factors, such as pH and temperature, were investigated. Results revealed that adsorption of ammonium occurred by means of ion exchange and molecule adsorption with the ≡Si–OH groups, while phosphate adsorption was based on the calcium phosphate precipitation reaction and formation of inner-sphere complexes with ≡ M–OH groups. The adsorption processes of ammonium and phosphate were well described by the pseudo-second-order kinetic model and the Freundlich isotherm model. Adsorption of phosphate was endothermic, while ammonium adsorption was exothermic. Furthermore, the maximum ammonium and phosphate adsorption capacities of NL was 23.24 mg N g–¹ and 4.01 mg P g–¹ at an initial pH of 9 and 10, respectively. Results demonstrated that nutrient-adsorbed NL used as compound fertilizer or conventional fertilizer superaddition was feasible for its high contents of N and P as well as its environmental friendliness.

Lanthanum-modified bentonite has potential for wide application in eutrophication control. We investigated P adsorption on a lanthanum-modified bentonite by analysis of adsorption kinetics, equilibrium, and the effect of environmental factors. P adsorption closely followed the pseudo-second-order kinetic model, and the isotherm was well described by the Langmuir model. This adsorbent could effectively immobilize P into the sediment, but the adsorption process was strongly dependent on pH, anions, and low molecular weight organic acids (LMWOAs). P adsorption increased with increasing pH from 0.52 mg P/g at pH 3.0 to 0.93 mg P/g at pH 7.0 with no adsorption at pH 11. P adsorption was strongly inhibited in the presence of anions and three LMWOAs, with P even re-released at high concentrations. These environmental factors should be given significant attention when considering the application of lanthanum-modified bentonite in eutrophication control.

A field investigation of contaminant transport beneath and around an uncontrolled landfill site in Huainan in China is presented in this paper. The research aimed at studying the migration of some chemicals present in the landfill leachate into the surrounding clayey soils after 17 years of landfill operation. The concentrations of chloride and sodium ions in the pore water of soil samples collected at depths up to 15 m were obtained through an extensive site investigation. The contents of organic matter in the soil samples were also determined. A two-dimensional numerical study of the reactive transport of sodium and chloride ion in the soil strata beneath and outside the landfill is also presented. The numerical modelling approach adopted is based on finite element/finite difference techniques. The domain size of approximately 300 × 30 m has been analysed and major chemical transport parameters/mechanisms are established via a series of calibration exercises. Numerical simulations were then performed to predict the long-term behaviour of the landfill in relation to the chemicals studied. The lateral migration distance of the chloride ions was more than 40 m which indicates that the advection and mechanical dispersion are the dominant mechanism controlling the contaminant transport at this site. The results obtained from the analysis of chloride and sodium migration also indicated a non-uniform advective flow regime of ions with depth, which were localised in the first few metres of the soil beneath the disposal site. The results of long-term simulations of contaminant transport indicated that the concentrations of ions can be 10 to 30 times larger than that related to the allowable limit of concentration values. The results of this study may be of application and interest in the assessment of potential groundwater and soil contamination at this site with a late Pleistocene clayey soil. The obtained transport properties of the soils and the contaminant transport mechanisms can also be used for the design of engineered barriers for the control of the long-term pollution of the site.

A novel aspect of the 8th International PCB Workshop at Woods Hole, MA, was the interaction between scientists and activists. While earlier workshops in this series had mentioned policy making, this Workshop focused on the problem of PCBs in schools. Focus on a problem brought an activist to give a plenary talk and facilitated a 1-day registration for other non-scientists to attend. The workshop was cohosted by the Superfund Research Programs at University of Iowa and Boston University and included active participation of each Program’s Research Translation and Community Engagement Cores. A mandate of each National Institute of Environmental Health Science (NIEHS)-funded Superfund Research Program is bidirectional communication between scientists and community groups. The authors describe the events leading up to community involvement in the Workshop and the substance of the community engagement aspects of the workshop, in particular the participation by a parent-teacher group, Malibu Unites. The authors also discuss the value of such communication in terms of making important research accessible to those who are most affected by the results and poised to use it and the value of making scientists aware of the important role they play in society in addressing difficult questions that originate in community settings.