Ciprofloxacin, griseofulvin, and rifampicin are three human antibiotics that are also widely used in the shrimp culture of Cangio coastal wetland (Vietnam, 10° 24’ 38” N, 106° 57’ 17” E). They have been detected in shrimp larvae pond and receiving water bodies. However, the environmental fate of these antibiotics in coastal wetland milieu is currently unknown. The aim of this study was to determine the degradation potential of these antibiotics in water and sediments from Cangio coastal wetlands. The effects of light, microbial activities, and presence of sediments on the degradation of all three antibiotics were investigated in “water-only” and “water–sediment” experiments. Results indicate that the environmental fate of those antibiotics was quite complex. Photodegradation seemed to play a major role in “water-only” system, since shorter t ₁/₂ was observed for ciprofloxacin, griseofulvin, and rifampicin, with light than in the dark, for both sterile and non-sterile conditions. Biodegradation played a minor role in the disappearance of the antibiotics and was overlaid by photodegradation. In addition, sorption to sediment was of major importance for antibiotics, especially for ciprofloxacin and rifampicin. The t ₁/₂ of these antibiotics in aqueous phase of “water–sediment” system was higher than for “water-only” experiments, indicating that a part of antibiotics were adsorbed by sediment. The biodegradation did not play a major role on sediment sorption of CIP and RIF, since no statistically significant differences between non-sterile and sterile conditions were observed. Only for GRI, the impact of the biodegradation to the sediment sorption could be found and led to the weak affinity to sediment sorption of this antibiotic. All three antibiotics were more sensitive to photodegradation than to biodegradation; however, the degradation rate was low. In addition, the sorption by sediment occurred also with a slow rate, so these antibiotics could recalcitrant persist in the coastal wetland environment.

Development and utilization of low-cost and effective adsorbents for the adsorption processes is a research focus in recent years. In this work, the porous and flexible film was prepared without any pretreatment from the feather keratin deposits produced during the extraction of soluble keratin from chicken feathers. Characteristics of the prepared biosorbent were investigated using thermogravimetric apparatus, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy. Batch adsorption assays were carried out to remove methylene blue (MB) from aqueous solution. The results showed that the extent of MB adsorption on the biosorbent increased with an increase in initial dye concentration, contact time, solution pH, and biosorbent dosage. The equilibrium data were best described by Langmuir isotherm than other isotherm models. The maximum monolayer adsorption uptake was 156.5 mg/g at pH 7 for an initial dye concentration of 200 mg/l. Kinetic studies indicated that the adsorption process of MB followed pseudo-second-order kinetics. Nevertheless, the intra-particle diffusion model confirmed that the adsorption of MB was a two-step process: a rapid surface adsorption followed by intra-particle diffusion. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° were calculated, indicating that the adsorption process was spontaneous and endothermic.

We determined basal levels of cholinesterase (ChE) and carboxylesterase (CbEs; two substrates: α-naphthyl acetate and 4-nitrophenylvalerate) in different tissues of tadpoles and adults of the frog Pseudis paradoxa and evaluated their use as complementary biomarkers of anti-cholinesterase pesticide exposure. ChE and CbEs sensitivity to malaoxon was also evaluated. Adults and tadpoles were collected with sweep net from temporary ponds located in natural riparian forests along the Paraná River (Garay Department, Santa Fe province, Argentina). We found significant differences in B-esterase activities between adults and tadpoles and among different tissues. The in vitro inhibition tests indicated that ChE is more sensitive to inhibition than CbEs. Our results suggest that basal ChE and CbE (α-NA and 4-NPV) activities in different tissues of adult and tadpoles P. paradoxa would be suitable biomarkers of pesticide exposure, and this amphibian species could be used as sentinel in field monitoring.

A pot experiment was conducted to investigate the effect of nitrogen fertilizer on CH₄ emission from a paddy soil under greenhouse conditions. The experiment was designed with two fertilizer types, i.e., controlled-release nitrogen fertilizer (CRNF) and urea (U), and two rice cultivars, i.e., herbicide-resistant transgenic rice (japonica line B2) and its parent conventional rice (japonica cv Xiushui 63). Compared with control (urea), one-time basal application of CRNF increased tiller number, plant height, biomass, and yield in rice and significantly decreased total CH₄ emission from the paddy soil. The total CH₄ emission was significantly lower from the transgenic cultivar than that from the conventional cultivar. It is suggested that CRNF and herbicide-resistant transgenic rice are helpful in mitigating CH₄ emission from the paddy soil.

This study evaluated the effect of the soil solution ionic strength (IS) on the adsorption of Zn, Cu, Cd, Pb, As, and P on aluminum mining by-product (AMB), as well as performed the toxicity characteristic leaching procedure test (TCLP) followed by semi-total digestion in order to evaluate whether the adsorbed elements can cause environmental health risks. We measured adsorption by reacting the adsorbent with Zn, Cu, Cd, Pb, As, and P solutions in low IS (47 mmol L⁻¹) and high IS (470 mmol L⁻¹). Subsequent cation and anion desorption was evaluated by adding electrolyte solutions to the remaining adsorption residue. After the desorption experiment, we performed the TCLP test followed by semi-total digestion. Changing the IS interfered on Zn, Cd, Cu, and As adsorption, while no effect was observed for Pb and P. Increasing IS decreased the desorbed amounts of Cd, Zn, Cu, and As. Among the studied elements, Cd and Zn were noteworthy for having adsorbed the least and desorbed the most. Disposal of the AMB after being used as adsorbent of Cd, Pb, and As has to be carefully made as it may present their contents above the concentration causing toxicity.

Effect of biochar, derived from unfertilized dates, on the immobilization of Cd and Ni, in a sandy loam alkaline soil, was investigated. The biochar was applied to the soil columns at the rate of 0.5, 1, and 2 % (w/w) artificially polluted with 10 mg kg⁻¹Cd and 100 mg kg⁻¹Ni. After 1 month incubation of soil-biochar mixture under ambient conditions, the soil bulk density was reduced by 0.19 g cm⁻³as compared with no biochar addition with increase in soil pH. A reduction of 53 % in the NH₄NO₃-extractable soil Ni was recorded as compared with the corresponding control without biochar addition. After incubation, the water-soluble Ni and NH₄NO₃-extractable soil Cd and Ni contents were significantly lower in all the biochar treatments than the control. A reduction of 53 % in the NH₄NO₃-extractable soil Ni was recorded as compared with the corresponding control. The biochar content separated from the incubated soil showed low concentrations of NH₄NO₃-extractable Cd and Ni. The total Ni and Cd contents recovered from biochar samples after incubation were 35.2 and 3.7 mg kg⁻¹, respectively. Their contents in soil were substantially reduced by the incorporation of biochar amendment (114 to 57.2 mg kg⁻¹Ni, 9 to 5.6 kg⁻¹Cd) as compared with the no-biochar control. Therefore, addition of the biochar improved the soil physical properties and succeeded in immobilizing the studied metals.

This paper presents a study of the combined process of adsorption and biodegradation in solid biologically activated carbon (AC) for the removal of salicylic acid aimed at determining the influence of the presence of biofilm on the process. Adsorption on AC and biodegradation of free cell cultures were studied separately so as to compare their performance with that of the combined biosorption system. The formation of bacterial biofilm on the surface of the carbon was investigated. The study was carried out using a range of synthetic solutions containing between 15 and 500 mg/L salicylic acid simulating an industrial effluent from the pharmaceutical industry. An individual bacterium, Pseudomonas putida (DSM 4478), was used to study the differentiated effects. Filtrasorb 400 and GAC 830 ACs were used in the adsorption processes and Filtrasorb 400 in the biofilm formation and combined biosorption processes. As regards, combined adsorption/biodegradation results indicated that the bioactivated carbon system outperformed the combination of conventional AC and biological water treatment processes when working with high pollutant concentrations.

A column experiment was conducted to evaluate the effectiveness of nanoscale zerovalent iron (nZVI) for the in situ immobilization of Pb and Zn in an acidic soil. The impact of nZVI on soil was evaluated by monitoring the physicochemical characteristics of the leachates and their ecotoxicological effects on three species, Vibrio fischeri, Artemia franciscana, and Caenorhabditis elegans. Treatment with nZVI resulted in more effective Pb immobilization in comparison to Zn and reduced the leachability by 98 and 72 %, respectively; the immobilization was stable throughout the experiment. Leachates from nZVI-treated soils showed lower toxicity than leachates from untreated ones. The highest toxicity in treated soils was observed in the first leachate, which presented high values of electrical conductivity due to the leachability of soil ions and those provided by the commercial nanoparticle suspension (Na and Fe). V. fischeri and C. elegans were more sensitive to leachates from nZVI-treated soils polluted with Zn than those from soils polluted with Pb; A. franciscana showed the opposite trend.

An innovative device for enhancing particle settling, referred to as the bottom grid structure (BGS), was tested in the forebay of an urban stormwater detention pond in two design variants. Results showed that compared to the simulated bare pond bottom (i.e., a reference condition), the BGSs collected more sediments during a three-month test period and also captured and retained some very fine particles (<32 μm) even under high flows. The improvements of particle removal rates expressed in multiples of removals for the bare bottom were 3.6, 7.3, and 11.2, respectively, for the particle size ranges 106 μm < D < 250 μm, 32 μm < D < 106 μm, and D < 32 μm. Because the BGS can retain much smaller particles than bare bottom sediment traps, the application of the BGS can be considered as equivalent to increasing the settling area of a particle removal facility about 5 to 60 times, depending on the size of settleable particles under consideration. This characteristic distinguishes the BGS from other sedimentation enhancement methods and makes it possible to treat stormwater with a wide particle size spectrum under high flow rates, with a relatively small footprint, and without using chemical settling aids or filtration.

It now is widely recognised that the global temperature is rising, a phenomenon which could alter the effects of pollution on wildlife. In order to assess the role of temperature and exposure to chlorine due to cooling water discharges, a battery of metabolic, oxidative stress and histological parameters were evaluated in Mytilus galloprovincialis after 15 and 30 days at 15 °C and at two increased temperatures (+5 and +10 °C). Diverse gill pathologies such as haemolymphatic sinus dilatation, an increased number of mucocytes and granulocytes as well as a lower number of cilia were observed after 30 days exposure at higher temperatures. Protein, amino acid, triglyceride and fatty acid levels decreased when the temperature increased, as a consequence of higher energetic demand. Similarly, acetylcholinesterase, catalase and glutathione S-transferase activities showed an inhibition at higher temperatures, although gill lipid peroxidation levels remained unaffected. Our results suggest that increased temperatures induce deterioration in the health status of the mussels and in their defensive capacity against a polluted environment.