Dissolved organic matter (DOM) in wastewater can be characterized using fluorescence excitation-emission matrix and parallel factor (EEM-PARAFAC) analysis. Wastewater from animal farms or pharmaceutical plants usually contains high concentration of antibiotics. In this study, the quenching effect of antibiotics on the typical components of DOM was explored using fluorescence EEM-PARAFAC analysis. Four antibiotics (roxarsone, sulfaquinoxaline sodium, oxytetracycline, and erythromycin) at the concentration of 0.5∼4.0 mg/L and three typical components of DOM (tyrosine, tryptophan, and humic acid) were selected. Fluorescence quenching effects were observed with the addition of antibiotics. Among these four antibiotics, roxarsone (2.9∼20.2 %), sulfaquinoxaline sodium (0∼32.0 %), and oxytetracycline (0∼41.8 %) led to a stronger quenching effect than erythromycin (0∼8.0 %). From the side of DOM, tyrosine and tryptophan (0.5∼41.8 %) exhibited a similar quenching effect, but they were higher than humic acids (0∼20.2 %) at the same concentration of antibiotics. For humic acid, a significant quenching effect was observed only with the addition of roxarsone. This might be the first report about the fluorescence quenching effect caused by antibiotics. The results from this study confirmed the interference of antibiotics on the fluorescence intensity of the main components of DOM and highlighted the importance of correcting fluorescence data in the wastewater containing antibiotics.

The development of shirasu balloons (SB) modified with polydopamine (PDA) has been conducted. The aim of this research is to increase the performance of shirasu balloons in the adsorption of methylene blue (MB). The SB modified with PDA (SB/PDA) was prepared by immersing SB in the dopamine solution in the aerobic alkaline condition. The prepared material was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS), specific surface area N₂ sorption, and zeta potential analysis. The adsorption behavior of SB and SB/PDA was investigated by studying the effect of the pH, adsorption kinetics, and effect of salt concentration. The adsorption kinetics of SB before and after modification was analyzed using two kinetics models, i.e., pseudo-first order and pseudo-second order. The adsorption isotherm was analyzed using Langmuir and Freundlich models. The adsorption study results showed that the adsorption isotherm fitted to Langmuir isotherm with a maximum capacity that could reach up to 26.17 mg g⁻¹ for SB and 36.23 mg g⁻¹ for SB/PDA. The adsorption kinetics showed that adsorption behavior followed the pseudo-second-order kinetic model and the equilibrium time for each material can be obtained at 5 min shaking time.

This study successfully applied an improved valvometry technique to measure waterborne copper (Cu), based on valve activity dynamics of the freshwater clam Corbicula fluminea. The improved valvometry technique allows the use of free-range bivalves and avoids causing stresses from experimental artifacts. The proposed daily valve rhythm models and a toxicodynamics-based Hill model were linked to predict valve dynamic responses under different Cu exposures with a circadian valve rhythm endpoint. Cu-specific detection threshold was 5.6 (95 % CI 2.1–9.3) and 19.5 (14.6–24.3) μg L⁻¹ for C. fluminea, based on response times of 300 and 30 min, respectively. Upon exposure to Cu concentrations in excess of 50 μg L⁻¹, the alteration of valve rhythm behavior was correlated with Cu concentration within 30 min, indicating notable sensing ability. This study outlines the feasibility of an in situ early warning dynamic biomonitoring system for detection of waterborne Cu based on circadian valve activities of C. fluminea.

Within the last few years, the presence of bentazone herbicide has been observed in many water resources. For the first time, removal of bentazone using mesoporous silica was investigated revealing reversible adsorption. The adsorption isotherm was well described using the Freundlich model. The affinity towards bentazone is strongly affected by pH in the range of 2–7, decreasing with the increase of the pH, becoming negligible at the neutrality. Regeneration of the adsorbent was possible, and a recovery as high as 70 % was obtained using CH₃OH-NaOH solution. Furthermore, appreciable recovery (47 %) was also obtained using water. Applications on the purification of lake water and wastewaters, both characterized by a significant organic carbon load, spiked with 2 mg L⁻¹ bentazone were tested, observing removal yields in the range of 61–73 %. Taking advantage of the fast adsorption kinetics observed, an in-flow purification treatment was set-up, with quantitative removal of bentazone from polluted water.

As increased greenhouse gas concentrations (GHG: N₂O, CO₂, CH₄) in our atmosphere remain a major concern, better quantifying GHG fluxes from natural systems is essential. In this study, we investigate GHG concentrations in saturated riparian sediments (dry, wet, mucky), streambed hyporheic zone sediments (pools, riffles), and stream water in a New York mountain stream for summer baseflow conditions, and attempt to identify the primary drivers (e.g., DO, DOC, NO₃⁻, and NH₄⁺, temp) of GHG concentrations at these locations. Although DO, DOC, NO₃⁻, and NH₄⁺ concentration patterns certainly explained some of the observed trends, the overall differences in GHG abundance in riparian water vs. hyporheic pool water vs. hyporheic riffle water strongly suggest that water velocity/mixing with the atmosphere is a key control on GHG concentration across locations. When all floodplain locations are considered, in-stream pools are hot spots of CO₂ and CH₄ concentrations relative to other in-stream locations. On the other hand, riparian areas are hot spots of CH₄ and CO₂ concentrations relative to stream locations. No clear patterns are observed for N₂O.

Adsorption of Reactive Orange 107 dye from aqueous solution was investigated using an activated carbon from Pinus elliottii sawdust chemically prepared with ZnCl₂. The optimum conditions for the adsorption of Reactive Orange 107 dye by the activated carbon, obtained by response surface methodology, were pH = 10, ionic strength = 0.4 mol L⁻¹, agitation rate = 200 rpm, and adsorbent dosage = 0.025 g. For the experimental data of the adsorption equilibrium, nonlinear models, i.e., the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms, were applied; the best correlation was found for the Langmuir model. The thermodynamic parameters were determined using the adsorption equilibrium constant of the Langmuir isotherm and the van ‘t Hoff equation. The parameters suggest an endothermic, ∆H°ₐdₛ = 16.97 kJ mol⁻¹, and spontaneous process, ∆G°ₐdₛ = −23.96, −25.23, −26.78, and −28.05 kJ mol⁻¹, at 298, 308, 318, and 328 K, respectively. The results indicate that the activated carbon was efficient for the adsorption of Reactive Orange 107 and has excellent potential for the treatment of colored effluents.

Surfactants always play a special role in wastewater processes due to their amphiphilic properties. The performance of ultrafiltration was investigated for the treatment of wastewater containing low-level anionic surfactant and trace-level nuclides. Results showed that sodium dodecyl benzene sulfonate (SDBS) below the critical micelle concentration (CMC) caused significant effects on membrane fouling and rejection of nuclides. The membrane flux decreased at SDBS concentrations below the CMC but increased at the concentrations near the CMC. The phenomenon was caused by two distinct effects of SDBS, pore blocking by the monomers and enhancement of nuclide scaling caused a decrease in flux, while hydrophilic modification of the membrane surface by micelles caused an increase in flux. The nuclides alone had no significant effect on membrane fouling, but the flux decreased upon an increase in nuclide concentration when coexisting with SDBS. After the addition of low-level SDBS, the rejections of nuclides increased sharply from 20–30 to 60–98 %. The rejections of Sr(II) and Co(II) were higher than those of Ag(I) and Cs(I) due to stronger complexation of SDBS with divalent cations compared with monovalent cations. Deposition of nuclides increased with the addition of SDBS and with increasing of nuclide concentration, resulting in more radioactive solid waste production and more frequent replacement of membrane module.

Industrial production of poultry meat is associated with indirect environmental impacts such as contributing to climate change and deforestation and other direct impacts such as the deterioration of the quality of surface waters. Poultry industry effluents are rich in organic matter, nitrogen, and phosphorus; nutrients can be removed from wastewater through the use of macrophytes and periphyton. An essay in mesocosms with poultry industry wastewater recirculation was developed in the presence and absence of a native macrophyte Spirodela intermedia and periphyton from a lowland stream (La Choza stream, Buenos Aires) where the effluent is poured. The diffusion of O₂, increased by water recirculation, had the effect of increasing the concentration of dissolved oxygen in wastewater. The presence of S. intermedia and algae periphyton significantly contributed to the removal rates (%) of solids (69.7 ± 3.9), ammonium nitrogen (84.0 ± 3.4), and total phosphorus (38.1 ± 1.8) from residual water and favored nitrification. The dominance of Bacillariophyceae on other groups of algae of periphyton and the low representation of Euglenophyceae indicated an advanced stage of the effluent treatment process at the end of the assay.

Trace metals contamination in commercial fish and crustaceans have become a great problem in Bangladesh. This study was conducted to determine seven trace metals concentration (Cr, Ni, Cu, Zn, As, Cd, and Pb) in some commercial fishes and crustaceans collected from coastal areas of Bangladesh. Trace metals in fish samples were in the range of Cr (0.15 − 2.2), Ni (0.1 − 0.56), Cu (1.3 − 1.4), Zn (31 − 138), As (0.76 − 13), Cd (0.033 − 0.075), and Pb (0.07 − 0.63 mg/kg wet weight (ww)), respectively. Arsenic (13 mg/kg ww) and Zn (138 mg/kg ww) concentrations were remarkably high in fish of Cox’s Bazar due to the interference of uncontrolled huge hatcheries and industrial activities. The elevated concentrations of Cu (400), Zn (1480), and As (53 mg/kg ww) were also observed in crabs of Cox’s Bazar which was considered as an absolutely discrepant aquatic species with totally different bioaccumulation pattern. Some metals in fish and crustaceans exceeded the international quality guidelines. Estimated daily intake (EDI) and target cancer risk (TR) revealed high dietary intake of As and Pb, which was obviously a matter of severe public health issue of Bangladeshi coastal people which should not be ignored and concentrate our views to solve this problem with an integrated approaches. Thus, continuous monitoring of these toxic trace elements in seafood and immediate control measure is recommended.

Dust pollution can cause a significant damage of environment and endanger human health. Our study aimed to investigate epiphytic lichens and bryophytes in relation to long-term alkaline dust pollution and provide new insights into the bioindicators of dust pollution. We measured the bark pH of Scots pines and the species richness and cover of two cryptogam groups in 32 sample plots in the vicinity of limestone quarries (up to ca. 3 km) in northern Estonia. The bark pH decreased gradually with increasing distance from quarries. We recorded the changes in natural epiphytic communities, resulting in diversified artificial communities on pines near the pollution source; the distance over 2 km from the quarries was sufficient to re-establish the normal acidity of the bark and natural communities of both lichens and bryophytes. The cover of lichens and the number of bryophytes are a more promising indicator of environmental conditions than individual species occurrence. We confirmed previously proposed and suggested new bioindicator species of dust pollution (e.g., Lecidella elaeochroma, Opegrapha varia, Schistidium apocarpum). Limestone quarrying activity revealed a “parapositive” impact on cryptogamic communities, meaning that quarrying might, besides disturbances of natural communities, temporarily contribute to the distribution of locally rare species.