The present study analyzes the acute and behavioral toxicity of two commercial formulations of endosulfan and atrazine (Gesaprim 90 WDG® and Zebra Ciagro®, respectively) on the cyclopoid copepod Mesocyclops longisetus. The studied behavior was the “escape ability” because of its ecological importance in natural predator–prey interactions. This was investigated using two experimental designs: (1) a simulated predator (applying a hydraulic device) and (2) a real one (the zooplanktophagous fish Cnesterodon decemmaculatus). Both pesticides resulted highly toxic to adults and nauplii at even relatively low concentrations and similar to those found in field studies. Copepods’ survival was not only directly affected but also indirectly through altering their escape behavior, which may have increased their vulnerability to predation. The escape ability, measured with the simulated predator was stimulated early (up to 6 h of exposition) but inhibited later (after 24 h of exposition). The predation experiments with the real predator were in accordance with these results. The comparison of both experimental designs corroborates the effectiveness of the hydraulic mechanism as a testing method.

Papaya seed was used as biosorbent for removal of tannery dye (Direct Black 38) from aqueous solution. The papaya seed was characterized, and it posseses macro/mesoporous texture, large pore size, and a surface containing various organic functional groups. The initial dye concentration, contact time, and pH significantly influenced the adsorption capacity. Equilibrium data were analyzed by the Langmuir and Freundlich isotherm models. The equilibrium data were best represented by the Langmuir isotherm, with a high adsorption capacity of 440 mg g⁻¹. Adsorption kinetic data were fitted using the pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Boyd models. The adsorption kinetics for the dye onto papaya seed was best described by second-order kinetic equation. The adsorption process mechanism was found to be controlled by both external mass transfer and pore diffusion, but the external diffusion was the dominating process. Papaya seeds showed to be a promising material for adsorption of Direct Black 38 dye from aqueous solution.

In this work, a coal combustion ash (CCA) has been tested as an alternative low-cost sorbent to commercial activated carbons (GAC) for cadmium and zinc removal from polluted water. To this aim, the effect of pH and metal concentration on CCA adsorption capacity has been investigated, and a comparative analysis with GAC has been carried out in the same experimental conditions. Furthermore, in order to improve CCA adsorption capacity, two different activation treatments of raw CCA have been tested. In particular, the CCA was subjected to a gasification process conducted with steam and to different acidic treatments, conducted either with hydrochloric acid or nitric acid at different acid concentrations. Experimental results showed that all the acid treatments determined a substantial reduction of both cadmium and zinc adsorption capacity. Differently, the steam gasification determined a substantial increase in adsorption capacity with respect to raw CCA, in particular for zinc as its adsorption capacity resulted even higher than the correspondent of GAC. Finally, a thorough analysis of sorbent physical and chemical properties and of adsorption data allowed the individuation of the main cadmium/zinc adsorption mechanism both on CCA and activated carbon, adequately described by the Freundlich model.

Buenos Aires Province (República Argentina) has undergone, in the last years, a great increase in agricultural activities based on the incorporation of new technologies and reduction of diversity to meet the increasing food demand. The increase of intensive agricultural systems in Argentina involves the use of fertilizers and pesticides such as herbicides, insecticides, and fungicides. Chlorpyrifos is one of the insecticides most widely used in these crops and constitutes a risk for human health, birds, and aquatic biota such as macroinvertebrates and fishes. In order to assess the possible contamination that the use of this product may represent for the environment, it is necessary to study its interaction with the different types of soils because fate and transport of environmental pollutants may be influenced by their interactions with soil particles. The behavior of chlorpyrifos was analyzed through the study of the recoveries from spiked solid environmental matrices. A strong dependence with organic matter content was observed along with an important dependence with the initial concentrations employed. Here, we show that chlorpyrifos behavior on solid matrices not only depends on soil chemical composition. A significant dependence of recovery percentages with initial concentrations of the pesticide was evident in all cases. Recovery percentages decreased with an increase of the initial concentration employed, no matter the variations in matrices of chemical compositions.

Geochemical characterization of two landfills, one closed and the other still active, both located near Komotini (Thrace, Greece), has been carried out. The aim was to provide an integrated and reliable methodology for a rapid assessment of the real impact of a municipal solid waste landfill, in the main environmental matrices (air and water) of the surrounding areas. The chemical (CO₂, CH₄, CO, H₂, N₂, and O₂ + Ar) and isotopic characterization (δ¹³C₍CO₂₎ and δ¹³C₍CH₄₎) of landfill gas and chemical (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄ ²⁻, HCO₃ ⁻, NH₄ ⁺, NO₃ ⁻, NO₂ ⁻, B, COD, Fe, Mn, As, Cr, Ni, Cu, Zn, Cd, Pb, and Hg) and isotopic analysis (δD, δ¹⁸O, tritium content, and δ¹³CDIC) of leachate, stream waters and groundwaters, and flux survey on the air–soil interface has been carried out. Combined chemical and isotopic analysis of the fluids collected inside and in the surroundings of the Komotini landfills supply a detailed picture of biogas emission and composition as well as of leachate chemistry and interaction with local waters. The results arising in this case study demonstrate that it is possible to propose a quick and reliable geochemical protocol to get a detailed picture of the state of health of the environment around a landfill.

A neutrophilic, autotrophic bacterium that couples iron oxidation to nitrate reduction (iron-oxidizing bacteria [IOB]) under anoxic conditions was isolated from a working bioremediation site in Trail, British Columbia. The site was designed and developed primarily to treat high concentrations of Zn and As that originate from capped industrial landfill sites. The system consisted of two upflow biochemical reactor cells (BCR) followed by three vegetated wetland polishing cells with sub-surface flow and a holding pond. During a 5-year period (2003–2007), the system treated more than 19,100 m³ of contaminated water, removing and sequestering more than 10,700 kg of As, Zn and sulfate at average input water concentrations of: As, 58.6 mg l⁻¹ (±39.9 mg l⁻¹); Zn, 51.9 mg l⁻¹ (±35.4 mg l⁻¹) and SO₄ ²⁻, 781.5 mg l⁻¹ (±287.8 mg l⁻¹). The bacterium was isolated in order to better understand the mechanisms underlying the consistent As removal that took place in the system. Analysis using Basic Local Alignment Search Tool (BLAST) database showed that the closest homologies are to Candidatus accumulibacterphosphatis (95 % homology), Dechloromonas aromatica (94 %), and Sideroxydans lithotrophicus ES-1 (92 %) Within the BCR cells, the IOB oxidized Fe²⁺ generated by iron-reducing bacteria (IRB); the source of the iron was most likely biosolids and coatings of iron oxide on locally available sand used in the matrix. We have provisionally designated the novel bacterium as TR1.

Palm oil mill effluent (POME) is an organic waste material produced at the oil palm mills. In its raw form, POME is highly polluting due to its high content of biological and chemical oxygen demand. In the present paper, POME was treated using double chamber microbial fuel cell with simultaneous generation of electricity. Polyacrylonitrile carbon felt (PACF), a new electrode material was used as electrode throughout the MFC experiments. Various dilutions of raw POME were used to analyze the effect of initial chemical oxygen demand (COD) on MFC power generation, COD removal efficiency and coulombic efficiency. Anaerobic sludge was used as inoculum for all the MFC experiments. Since this inoculum originated from POME, it showed higher potential to generate bioenergy from complex POME. Anaerobic sludge enhanced the power production due to better utilization of substrates by various types of microorganisms present in it. Among the raw POME and different concentrations of POME used, the PACF with raw POME showed the maximum power density and volumetric power density of about 45 mW/m² and 304 mW/m³, respectively, but it showed low coulombic efficiency and low COD removal efficiency of about 0.8 % and 45 %, respectively. The MFC PACF with 1:50 dilution showed higher COD removal efficiency and coulombic efficiency of about 70 % and 24 % but showed low power density and low volumetric power density of about 22 mW/m² and 149 mW/m³, respectively. The formation of biofilm onto the electrode surface has been confirmed from scanning electron microscopy (SEM) experiments. The results confirm that MFC possesses great potential for the simultaneous treatment of POME and power generation using PACF as electrode and also shows that initial COD has great influence on coulombic efficiency, COD removal efficiency and power generation.

Graphene oxide (GO) prepared by modified hummers method was used as adsorbent for removal of heavy metal ions. The oxygenous functional groups on the surface of GO were primarily responsible for the sorption of metal ions. The effects of the parameters of pH value, contact time, Cu(II) concentration, and adsorbent dosage on adsorption were examined. The sorption process conformed to the Freundlich isotherm, and the maximum sorption capacity of 117.5 mg g⁻¹ was observed at an initial pH value of 5.3 after agitating for 150 min. It was also found that Cu-pretreated GO could be desorbed by HCl and the reusability of GO could still maintain above 90 % of its initial capability after ten cycles. The results suggest that GO is an effective adsorbent for copper ions removal in water treatment.

The impacts of dissolved organic matter (DOM) on the removal of 17β-estradiol (E2) in horseradish peroxidase (HRP)-mediated oxidative coupling systems were investigated in this study. The results showed that the removal rate of E2 and the affinity of HRP to E2 had been significantly decreased in the presence of DOM. Compared with urban sludge DOM (USDOM), river sediment DOM (RSDOM), which features relatively low aromaticity and molecular weight and a large number of O-containing groups, more strongly inhibited the E2–HRP–H₂O₂ reactions than USDOM. The products were analyzed with electrospray ionization mass spectrometry. The results suggested that the self-coupling of E2 was suppressed in the presence of DOM, likely resulting from cross-coupling between DOM and E2 or self-coupling of DOM in the HRP system. The results are useful in understanding the fate of estrogens in natural systems.

Biochars derived from the straws of rice, soybean, and peanut were prepared and modified with aluminum [Al(III)]. These modifications shifted zeta potential-pH curves of the biochars in a positive-value direction and changed surface charge of biochars from negative to positive under acidic conditions. The isoelectric points for 0.6 M Al(III)-modified rice, soybean, and peanut straw biochars were 8.0, 7.8, and 7.5, respectively. Electrostatic attraction of the positively charged surfaces on Al(III)-modified biochars to arsenate [As(V)] enhanced its sorption. The sorption of As(V) by these Al(III)-modified biochars was investigated in batch experiments. Al(III)-modified biochars had greater sorption capacity under acidic conditions compared with corresponding unmodified biochars. While unmodified biochars sorbed negligible amounts of As(V), their Al(III)-modified forms sorbed 445-667 mmol kg-1 at pH 5.0, which were predicted by the Langmuir equation. Modifications with 0.3 M Al3+ improved sorption capacity of As(V) on soybean straw biochar to 445 mmol kg-1, which was further increased by 50 % after modification with 0.6 M Al3+. These As(V) sorption capacities of biochars modified with 0.6 M Al3+ were larger than those of Fe/Al oxides determined at the same pH, which were < 500 mmol kg-1. Thus, biochars modified with 0.6 M Al3+ could substitute Fe/Al oxides used for water purification. However, the sorption of As(V) by the Al(III)-modified biochars increased with decreasing suspension pH. Thus, As(V) removal by Al(III)-modified biochars is suggested to be conducted under acidic conditions, but at pH > 4.0. © 2013 Springer Science+Business Media Dordrecht.