INTRODUCTION: The use of veterinary drugs in food production focuses on the control and improvement of animal health. The disadvantage of this practice is that pharmaceuticals and their metabolites are released into the environment, finding their way to natural water systems and becoming a potential risk to non-target organism. METHODS: This paper reports the development and validation of a quantitative method, based on high-performance liquid chromatography coupled to tandem mass spectrometry, for the simultaneous analysis of 21 veterinary drugs, antimicrobials, corticosteroids, coccidiostats and antifungal agents, in surface water. RESULTS: The precision of the method was established by calculating the mean recoveries, which were in the range of 94–101%. The developed method was employed to conduct the first monitoring study on the presence of veterinary drugs in the Galicia region, Northwest of Spain and was applied to 235 surface water samples. Eleven veterinary drugs were detected at concentrations from below the limit of quantification to 2,978.6 ng L−1. Limits of detection and quantification were in the range of 6.2 (betamethasone, cortisone, decoquinate, dexamethasone, maduramycin, monensin, narasin, salinomycin, sulfachloropyridazine, sulfamethoxypyridazine and trimethoprim) to 12.5 ng L−1 (for the rest of the selected drugs) and 12.5 (betamethasone, cortisone, decoquinate, dexamethasone, maduramycin, monensin, narasin, salinomycin, sulfachloropyridazine, sulfamethoxypyridazine and trimethoprim) to 25.0 ng L−1 (for the remaining pharmaceuticals), respectively. CONCLUSION: Sulfonamides were the group most frequently found, which are widely used in veterinary medicine.

PURPOSE: The oxone process for azo dye decolorization has drawbacks such as difficulties with reuse, risks of secondary pollution, and high costs associated with UV irradiation. This study aims to explore the use of oxone for decolorization in the absence of catalyst and under natural sunlight conditions (i.e., oxone/natural sunlight system) and evaluate the impacts of operating parameters (reagent dosage, initial methyl orange (MO) concentration, and initial pH) and coexisting substances (humic acid, NO 3 − , metal ions) on the system’s decolorization efficiency. METHODS: Four levels of operating parameters were configured under a Taguchi L16 orthogonal array design to examine their effects on decolorization efficiency. Fractional factional design was then used to derive the optimal combination of operating parameters, under which the effects of coexisting substances at various concentrations were examined. In addition, H2O2, CH3OH, and (CH3)3COH were used to derive the possible reaction mechanisms in the oxone/sunlight system, while ultrasonic power was used to shorten the reaction time. RESULTS: In the oxone/sunlight system, (1) the MO decolorization efficiency reaches 96.4% under the optimal operating conditions: initial concentration, 100 mg L−1; initial pH 6.04; dosage of reagent, 3 mmol L−1; and reaction time, 30 min. (2) Coexisting substances do not affect the overall decolorization efficiency. (3) The decolorization of MO in the oxone/sunlight system takes place mainly via oxidation by SO 4 [Symbol: see text]− . (4) Ultrasonic irradiation could remarkably accelerate the MO decolorization process. CONCLUSION: Effective for MO decolorization, the oxone/sunlight system improves over the traditional oxone process with advantages of lower costs and avoiding secondary pollution by catalyst.

INTRODUCTION: This study was hypothesized that salicylic acid elevates the level of antioxidant system that will protect plants from the stress generated by nickel and/or salinity. MATERIALS AND METHODS: Seeds of Brassica juncea were sown in sand amended with NiCl2 (100 mg kg−1) and/or 15-day-old seedlings supplied for 3 days with NaCl (150 mM) and were then, at 20-day stage, sprayed with salicylic acid (10−5 M) to assess selected morphological, physiological, and biochemical parameters at 30-day stage. RESULTS: The combination of Ni and NaCl proved most deleterious and exhibited significant decline in growth, leaf water potential, the level of pigments, and photosynthetic attributes. However, the follow-up treatment with salicylic acid detoxified the stress-generated damages caused by the combination (NiCl2 and NaCl) and also significantly improved values for the above parameters. The NiCl2 and/or NaCl increased electrolyte leakage, lipid peroxidation, and H2O2 content but decreased the membrane stability index and activity of nitrate reductase and carbonic anhydrase. However, the salicylic acid treatment in the presence or absence of the stress improved the activity of nitrate reductase and carbonic anhydrase. The activity of antioxidative enzymes and the level of proline exhibited a significant increase in response to NiCl2 and/or NaCl stress and which enhanced further with the spray of salicylic acid. CONCLUSIONS: It is concluded that the elevated level of antioxidative enzymes and level of proline might be responsible for minimizing the Ni and/or salinity-induced toxicity in Indian mustard which is manifested in terms of improved growth and photosynthesis.

PURPOSE: Polyethylene succinate (PES) is a biodegradable synthetic polymer and therefore widely used as a base material in plastic industry to circumvent the environmental problems related with the non-biodegradability of other polymers like polyethylene. Till date only few organisms have been reported to have the ability to degrade PES. Therefore for better management of PES-related environmental waste, the present study is targeted towards isolating mesophilic organism(s) capable of more efficient degradation of PES. RESULTS: Strain AKS2 was isolated from soil based on survival on a selection plate wherein PES was used as sole carbon source. Ribotyping and biochemical tests revealed that AKS2 is a new strain of Pseudomonas. Scanning electron and atomic force microscopic analysis of the PES films obtained after incubation with AKS2 confirmed PES-degradation ability of AKS2, wherein an alteration in surface topology was observed. The kinetics of PES weight loss showed that AKS2 degrades PES maximally during its logarithmic growth phase at a rate of 1.65 mg/day. This degradation is mediated by esterase activity and may also involve cell-surface hydrophobicity. It has also been observed that AKS2 is able to degrade PES considerably even in the presence of glucose, which is likely to increase the bioremediation potential of this isolate. CONCLUSION: A new strain of Pseudomonas has been isolated from soil that is able to adhere to PES and degrade this polymer efficiently. This organism has the potential to be implemented as a useful tool for bioremediation of PES-derived materials.

The urban air quality in Barcelona in the Western Mediterranean Basin is characterized by overall high particulate matter (PM) concentrations, due to intensive local anthropogenic emissions and specific meteorological conditions. Moreover, on several days, especially in summer, natural PM sources, such as long-range transported Saharan dust from Northern Africa or wildfires on the Iberian Peninsula and around the Mediterranean Basin, may influence the levels and composition of the organic aerosol. In the second half of July 2009, daily collected PM10 filter samples in an urban background site in Barcelona were analyzed on organic tracer compounds representing several emission sources. During this period, an important PM peak event was observed. Individual organic compound concentrations increased two to five times during this event. Although highest increase was observed for the organic tracer of biomass burning, the contribution to the organic aerosol was estimated to be around 6 %. Organic tracers that could be related to Saharan dust showed no correlation with the PM and OC levels, while this was the case for those related to fossil fuel combustion from traffic emissions. Moreover, a change in the meteorological conditions gave way to an overall increase of the urban background contamination. Long-range atmospheric transport of organic compounds from primary emissions sources (i.e., wildfires and Saharan dust) has a relatively moderate impact on the organic aerosol in an urban area where the local emissions are dominating.

PURPOSE: Dechlorination of polychlorinated biphenyls (PCBs) by nanoscale zerovalent iron (NZVI) is often strongly hindered by increased pH because large amounts of H+ ions were consumed during the surface reaction. The main objective of this work was to evaluate the effect of pH control in acid on the dechlorination processes of PCBs and to compare the dechlorination efficiency between 2,4,4′-trichlorobiphenyl (2,4,4′-CB) and the extracted PCBs from the field PCBs-contaminated soil in this system. METHODS: The reaction solution pH was controlled to be weakly acid (4.90–5.10) with an automatic pH control system, in which the dechlorination of 2,4,4′-CB and extracted PCBs from a PCBs-contaminated soil by NZVI and palladized nanoscale zerovalent iron (NZVI/Pd) was investigated. RESULTS: To control the reaction solution pH to be acid actually increased the dechlorination rate of PCBs by NZVI and NZVI/Pd. The observed normalized pseudo-first-order dechlorination rate constants (k obs) of 2,4,4′-CB increased from 0.0029 min−1 (no pH control) to 0.0078 min−1 (pH control) by NZVI and from 0.0087 min−1 (no pH control) to 0.0108 min−1 (pH control) by NZVI/Pd. In the case of NZVI/Pd, the chlorines in the para position were much more easily dechlorinated than ortho position, and biphenyl was the dominating product. As the solution pH was controlled at 4.90–5.10, the dechlorination rate constants of PCB congeners extracted from soil (k obs) were 0.0027–0.0033 min−1 and 0.0080–0.0098 min−1 by NZVI and NZVI/Pd, respectively. CONCLUSIONS: To keep the reaction solution to be weakly acid markedly increased the dechlorination rate of PCBs, which may offer a novel technology in the remediation of PCBs-contaminated soil.

PURPOSE: The characteristics of organics in sulphite pulp mill effluent and in the receiving environment of effluent discharge were investigated to assess the basis for the persistence or attenuation of colour. METHODS: Characterization of organics was conducted through determination of SUVA, specific colour, and molecular weight distribution of organics using high performance size exclusion chromatography and by solid-state 13 C cross polarization (CP) NMR. The characteristics of organics from mill wastewater before and after secondary aerobic treatment, followed by lime treatment and from the receiving environment, an enclosed brackish lake were compared. Changes in the character of organics in lake water over a period of 14 years were studied in the context of changes in mill processing and climate impacts. RESULTS: High colour in mill effluent and in receiving waters correlated with high SUVA and specific colour levels, high molecular weight range and aromatic content. Conversely, lake waters with low colour had UV absorbing compounds of much lower molecular weight range and low relative abundance of aromatic compounds. Attenuation of colour and changes in the character of organics in the receiving environment coincided with increased concentrations of metal cations. CONCLUSIONS: These increased concentrations appear to be due to the effects of climate change, lake management and their presence in mill effluent, with subsequent discharge to the lake. Attenuation of colour was found to be predominantly through removal of high molecular weight aromatic compounds where the removal processes could be through adsorption and co-precipitation with divalent metals, as well as through dilution processes.

INTRODUCTION: We report on the analysis of 4,4′-dichlorodiphenyltrichloroethane (4,4′-DDT) and its metabolites in thatch and branch samples constituting the wall materials of dwellings from South African subtropical areas. This approach was used to assess the exposure to DDT in the residents of the dwellings after indoor residual spraying (IRS) following recommended sanitation practices against malaria vectors. DISCUSSION: Examination of the distributions of DDT compounds (2,4′-DDT, 4,4′-DDT and its metabolites) in 43 dwellings from the area of Manhiça (Mozambique) has shown median concentrations of 19, 130, and 23 ng/g for 2,4′-DDT, 4,4′-DDT, and 4,4′-DDE, respectively, in 2007 when IRS implementation was extensive. The concentrations of these compounds at the onset of the IRS campaign (n = 48) were 5.5, 47, and 2.2 ng/g, respectively. The differences were statistically significant and showed an increase in the concentration of this insecticide and its metabolites. Calculation of 4,4′-DDT in the indoor air resulting from the observed concentrations in the wall materials led to the characteristic values of environments polluted with this insecticide.

PURPOSE: An online cloud-point extraction (CPE) coupled with flow injection method is developed for the separation and preconcentration of palladium and lead from various matrices using flame atomic absorption spectrometry (FAAS). METHOD: The method employs the formation of complexes of the metallic species with dimethylglyoxime, which are subsequently entrapped in the micelles of the surfactant Triton X-114, upon increase of the solution temperature to 60°C and loaded into the flow injection system at a flow rate of 4.6 mL min−1. The surfactant rich-phase was retained in a minicolumn packed with animal wool at pH 6 and eluted with 1.0 mol L−1 nitric acid in methanol at a flow rate of 1.1 mL min−1 directly into the nebulizer of the FAAS. The CPE variables and flow injection conditions affecting the analytical performance of the combined methodology was studied and optimized. RESULTS: Under the optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 51 and 44, and the limit of detections were 1.0 and 1.4 ng mL−1 for palladium and lead, respectively. Finally, the developed method was applied for the determination of palladium and lead in street dust, soil, radiology waste, catalytic converter, and urban aerosol samples. CONCLUSIONS: Cloud-point extraction coupled with flow injection-FAAS was proposed as an effective preconcentration and separation method for Pd and Pb determination in radiology waste, road dust, soil, and urban aerosol samples. The most favorable feature of this method is its much higher selectivity, sensitivity, rapidity, good extraction efficiency, and employs the green chemistry concept, as it does not require the addition of toxic chemicals. In addition, this proposed method gives very low detection limits and good relative standard.

The present study aims to investigate the EDTA catalyzed reduction of nitrate (NO 3 − ) by zero-valent bimetallic (Fe–Ag) nanoparticles (ZVBMNPs) in aqueous medium and to enumerate the effect of temperature, solution pH, ZVBMNPs dose and EDTA concentration on NO 3 − reduction. Batch experimental data were generated using a four-factor Box–Behnken design. Optimization modeling was performed using the response surface method for maximizing the reduction of NO 3 − by ZVBMNPs. Significance of the independent variables and their interactions were tested by the analysis of variance and t test statistics. The model predicted maximum reduction capacity (340.15 mg g−1 NO 3 − ) under the optimum conditions of temperature, 60 °C; pH 4; dose, 1.0 g l−1; and EDTA concentration, 2.0 mmol l−1 was very close to the experimental value (338.62 mg g−1) and about 16 % higher than the experimentally determined capacity (291.32 mg g−1). Study demonstrated that ZVBMNPs had higher reduction efficiency than Fe0 nanoparticles for NO 3 − . EDTA significantly enhanced the NO 3 − reduction by ZVBMNPs. The EDTA catalyzed reduction of NO 3 − by ZVBMNPs can be employed for the effective decontamination of water.