Evaluation of perfluorooctane surfactants in a wastewater treatment system and in a commercial surface protection product

The origin and amount of perfluorooctane surfactants in wastewater treatment systems, and the transformation these compounds may undergo during treatment, were evaluated through measurement and experiment. Influent, effluent, and river water at the point of discharge for a 6-MGD wastewater treatment plant (WWTP) were screened for eight perfluorooctane surfactants. N-EtFOSAA was quantified in influent (5.1 +/- 0.8 ng/L), effluent (3.6 +/- 0.2 ng/ L), and river water samples (1.2 +/- 0.3 ng/L), while PFOS and PFOA were quantified in effluent (26 +/- 2.0 and 22 +/- 2.1 ng/L, respectively) and river water (23 +/- 1.5 and 8.7 +/- 0.8 ng/L, respectively). Signals for PFOS and PFOA were observed in influent samples, but exact quantitative determination could not be made due to low recoveries of these two compounds in field spike samples. Although the source of PFOS and PFOA observed in WWTP effluents is not clear, two hypotheses were examined: (1) the highly substituted perfluorooctane surfactants that constitute commercially available fabric protectors can be transformed to PFOS and PFOA during biological treatment in wastewater treatment systems, and (2) the end products themselves are directly introduced to WWTPs because they are present as residual in the commercial mixtures. Biotransformation experiments of 96 h were run to determine whether N-EtFOSE (a primary monomer used in 3M's polymer surface protection products) could be transformed to lesser-substituted perfluorooctane compounds in bioreactors amended with aerobic and anaerobic sludge from the sampled plant. At the end of the aerobic biotransformation experiment, N-EtFOSAA and PFOSulfinate were the only two metabolites formed and each accounted for 23 +/- 5.0% and 5.3 +/- 0.8% of the transformed parent on a molar basis, respectively. Transformation of N-EtFOSE was not observed under anaerobic conditions. A sample of a commercially available surface protection product from 1994 was analyzed and found to contain six of the targeted perfluorinated surfactants, including PFOS and PFOA. These findings suggest transformation of precursors within wastewater treatment is not an important source of these compounds compared to direct use and disposal of products containing the end products as residual amounts.     

Emission and control of nitrous oxide from a biological wastewater treatment system with intermittent aeration

Nitrous oxide (N2O) can be emitted as a by-product of the process of nitrogen removal from wastewater. Two methods of complete denitrification and media application were studied in lab-scale intermittent aeration reactors fed with domestic wastewater to refine methods of controlling the N2O emission rate. A study on cyclic patterns showed that the highest N2O emission rate was at the beginning of the aerobic phase rather than the anoxic phase. This was probably because the nitrifying bacteria had accumulated nitrite nitrogen (NO2-) under low DO conditions. Methanol as an external carbon source was added during the anoxic phase to reduce nitrate nitrogen (NO3-) when denitrification was completed. The N2O emission rates in both the aerobic and anoxic phases were significantly influenced by residual NO3-, increasing monotonically as the concentration of NO3- in the reactor increased. Over 95% of average N2O emissions in both the aerobic and anoxic phases were prevented when methanol was added. The biofilm reactor showed similar patterns to those of the non-biofilm reactor in track behavior, but the former was more effective in the reduction of N2O emissions.     

Treatment of municipal wastewater treatment plant effluents with modified photo-Fenton as a tertiary treatment for the degradation of micro pollutants and disinfection

The goal of this paper was to develop a modified photo-Fenton treatment able to degrade micro pollutants in municipal wastewater treatment plant (MWTP) effluents at a neutral pH with minimal iron and H(2)O(2) concentrations. Complexation of Fe by ethylenediamine-N,N'-disuccinic acid (EDDS) leads to stabilization and solubilization of Fe at natural pH. Photo-Fenton experiments were performed in a pilot compound parabolic collector (CPC) solar plant. Samples were treated with solid phase extraction (SPE) and analyzed by HPLC-Qtrap-MS. The rapid degradation of contaminants within the first minutes of illumination and the low detrimental impact on degradation of bicarbonates present in the water suggested that radical species other than HO(?) are responsible for the efficiency of such photo-Fenton process. Disinfection of MWTP effluents by the same process showed promising results, although disinfection was not complete.     

Corn salad (Valerianella locusta (L.) Laterr.) growth in a water-saving floating system as affected by iron and sulfate availability

BACKGROUND: Unbalanced nutrient availability causes disequilibrated plant growth, which can result in a worsening of harvested product quality, such as high nitrate content in edible tissues. To cope with this problem, improved knowledge of the mechanisms involved in nutrient acquisition and regulation is necessary. For this purpose the responses of acquisition mechanisms of N, Fe and S were studied as a function of Fe and S availability using two corn salad cultivars grown hydroponically, considering also aspects related to N metabolism. RESULTS: The results showed that an increase in Fe or S availability enhanced nitrate uptake and assimilation, which in turn increased biomass production of leaves with lower nitrate content. In particular, high S availability exerted a positive effect (gene expression and functionality) both on the uptake and metabolism of N and on Fe acquisition mechanisms. CONCLUSION: The data presented here show close interactions between N, S and Fe, highlighting that relevant improvements in yield and quality from soilless culture might also be obtained through appropriate adjustments of nutrient availability. In this respect, concerning the role of S in the acquisition mechanisms of N and Fe and in N metabolism, its level of availability should be taken into high consideration for equilibrated plant growth. Copyright © 2010 Society of Chemical Industry     

Degradation of cell walls of forages by sequential treatment with sodium hydroxide and a commercial cellulase preparation

Cell walls of barley straw (whole sample and stem), Italian ryegrass (shoot) and lucerne (mature stem) were treated sequentially with NaOH followed by a commercial ‘cellulase’ preparation and, in other experiments, with the cellulase followed by the alkali. The phenolic compounds released by NaOH were determined and related to increases in the degradability of the walls as measured with cellulase. Two sequential treatments of the cell walls of barley straw increased degradability from 11% on treatment with cellulase alone to 87%, compared with increases from 72 to 99% and from 19 to 54% for the ryegrass and lucerne walls respectively. The first alkali treatment released ferulic and p-coumaric acids from the walls of barley and ryegrass together with other u.v. absorbing compounds, whereas the compounds released by the second alkali treatment did not include these two acids. The treatment with alkali did not release either ferulic acid or p-coumaric acid from the walls of lucerne and the amounts of other u.v. absorbing compounds that were released were much smaller.     

Uptake of arsenic species by turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) treated with roxarsone and its metabolites in chicken manure

Roxarsone is an organoarsenic feed additive that can be metabolised to other higher toxic arsenic (As) species in animal manure such as arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, 3-amino-4-hydroxyphenylarsonic acid and other unknown As species. The accumulation, transport and distribution of As species in turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) amended with roxarsone and its metabolites in chicken manure were investigated. Results showed arsenite was the predominant As form, followed by arsenate in turnip and lettuce plants, and a low content of dimethylarsinic acid was detected only in lettuce roots. Compared with the control plants treated with chicken manure without roxarsone and its metabolites, the treatments containing roxarsone and its metabolites increased arsenite content by 2.0–3.2% in turnip shoots, by 6.6–6.7% in lettuce shoots, by 11–44% in turnip tubers and by 18–20% in lettuce roots at two growth stages. The enhanced proportion of arsenate content in turnip shoots, turnip tubers and lettuce roots was 4.3–14%, 20–35% and 70%, respectively, while dimethylarsinic acid content in lettuce roots increased 2.4 times. Results showed that the occurrence of dimethylarsinic acid in lettuce roots might be converted from the inorganic As species and the uptake of both inorganic and organic As compounds in turnip and lettuce plants would be enhanced by roxarsone and its metabolites in chicken manure. The pathway of roxarsone metabolites introduced into the human body via roxarsone → animal → manure → soil → crop was indicated.     

Quantification of rotenone in seeds of different species of yam bean (Pachyrhizus sp.) by a SPE HPLC-UV method

This study describes the development of a validated method for the quantification of rotenone in yam bean. The milled seeds were submitted to a Soxhlet dichloromethane extraction which allowed extracting 90% of the seeds rotenone. Elimination of the lipids was obtained via solid phase extraction. Rotenone was eluted with dichloromethane/methanol and the solution dried under vacuum and solubilised directly in methanol before injection in HPLC. The whole process was realised as much as possible protected from light and at temperatures lower than 40 °C which allowed high recovery rates of spiked rotenone. Total error was used as criterion for the validation process and accuracy profiles drawn. The method allows the quantification of rotenone in yam bean seeds from 0.07% up to 1.25% (w/w). This method was applied to the quantification of rotenone in the seeds of several accessions of Pachyrhizus erosus and Pachyrhizus ahipa. The results range from 1.13 to 2.76 mg/g dry material.     

Wheat sprouts (Triticum aestivum Linn.) cultured by a smart farm system ameliorate NAFLD through the AMPK-mediated SREBP signaling pathway

Wheat is cultivated worldwide and is the most widely distributed food crop. Wheat is a staple crop in many countries. However, the effects of various cultivation methods on the efficacy of wheat sprouts have not been determined. This study investigated wheat sprouts obtained using a standardized smart farm system (WS-S) to improve the effects of non-alcoholic fatty liver disease (NAFLD) and molecular mechanism. Wheat sprouts significantly attenuated the accumulation of lipid droplets in FFA-induced HepG2 cells through AMPK pathway activity. In vivo experiments showed that WS-S significantly lowered body weight gain and decreased adipose tissue, lipid, aspartate transaminase, and alanine aminotransferase levels in HFD/F-treated mice. Furthermore, WS-S stimulated the phosphorylation of ACC and peroxisome proliferator-activated receptor alpha via the AMPK pathway and inhibited SREBP-1/FAS signaling to inhibit de novo adipogenesis and increase fatty acid oxidation. These results suggest that WS-S ameliorates NAFLD by regulating fatty acid metabolism via the AMPK pathway.

     

Monitoring nisin desorption from a multi-layer polyethylene-based film coated with nisin loaded HPMC film and diffusion in agarose gel by an immunoassay (ELISA) method and a numerical modeling

Polyethylene-based films coated with nisin loaded HPMC films were put in contact with food simulants, i.e. agarose gels with 5 or 30% (w/w) fat. Nisin desorption from the multi-layer films and diffusion in agarose gels were monitored by ELISA (Enzyme Linked ImmunoSorbent Assay). The data obtained after 2 or 6 days of contact between antimicrobial films and agarose gels were employed to determine nisin mass transfer by numerical modeling following Fick's second law. The values were in the range from 0.87 × 10^? 3 m s^? 1 to 4.30 × 10^? 3 m s^? 1 and 6.5 × 10^? 11 m² s^? 1 to 3.3 × 10^? 10 m² s^? 1, for nisin apparent desorption and diffusion coefficients, respectively. The diffusion process was governed by interactions between food matrix simulant and nisin. Moreover, it was observed that the polymer in the coating did not modify plastic film initial mechanical resistance and water vapor permeability.Industrial relevanceThis paper concerns active packaging, considered as a new approach to preserve food shelf life. Active packaging is a real gain for plastic and Food industrials. The paper deals with coating as a manner to activate packaging. The impact of coating on film properties is investigated.Also, predictive models are proposed to determine antimicrobial agent desorption and diffusion during some storage conditions.     

Starch properties of Amaranthus pumilus (seabeach amaranth): a threatened plant species with potential benefits for the breeding/amelioration of present Amaranthus cultivars

This study reports on the physicochemical properties of starch isolated from the seeds of Amaranthus pumilus (a threatened plant species) and compares it to that of the commonly cultivated/commercially produced Amaranthus hypochondriacus K343 (Plainsman). Seeds of both investigated species were found to possess comparable quantities/levels of total starch. Although no significant differences (P⩾0.05) were found between the composition of the two starches with regard to their moisture, ash, protein and fat contents, the starch of A. pumilus was found to contain significantly higher (P⩾0.05) amounts of amylose than that of A. hypochondriacus. The higher levels of amylose found in A. pumilus starch were believed to be responsible for the higher differential scanning calorimetric To, Tp and Te starch temperatures than those of A. hypochondriacus starch which would indicate higher levels of ordered crystalline structure in the former. Scanning electron microscopy and integrated light scattering techniques both revealed a uniform average starch granule diameter of approximately 1 μm for both investigated species. This study further supports and compliments a previous study which showed that much genetic diversity exists between A. pumilus and A. hypochondriacus, indicating that potential breeding possibilities for the improvement of commonly cultivated amaranth lines do exist, if A. pumilus is not first driven to extinction.     

Phytosanitary treatment of European pallets by microwave: developing a program to ensure compliance with ISPM 15 and monitoring its efficacy on the house longhorn beetle (Hylotrupes bajulus L.)

Microwave heating was recently approved by the FAO as a significantly effective phytosanitary treatment for wood packaging material. According to ISPM 15 (FAO 2009), the target organisms are eradicated if a temperature higher than 60 °C is maintained for 60 s across the entire profile of the board (i.e. 60 °C/60 s). A study using pallet boards was carried out in order to set up a treatment program that would meet ISPM 15 requirements in terms of wood temperature and insect mortality. A 4 m-long industrial tunnel oven (maximum power of 28.8 kW) was used to carry out the experiments. Temperature was measured by means of a VarioCAM^® infrared camera. The most relevant results found were: (i) achieving a mean temperature of 63.2 °C (Populus sp.) or 64.8 °C (Pinus sylvestris L.) on the upper surface of 22 mm-thick boards enabled compliance with FAO requirements (i.e. 60 °C/60 s), whatever the moisture content, basic density and initial temperature of the wood (provided the latter exceeded 0 °C); (ii) larvae >150 mg represented the most microwave-resistant life stage of Hylotrupes bajulus L.; (iii) the mortality rate of the larvae was influenced by the moisture content of the boards. Using the Gompertz model, the upper surface temperature was estimated that would be needed to achieve a 99.99683 % mortality rate (the Probit 9 mortality level of efficacy) for the most microwave-resistant life stage of H. bajulus. This temperature was estimated to be 46.8 and 57 °C for wood with >50 and <25 % moisture content, respectively.     

分散式固相萃取结合高效液相色谱法测定植物油中苯并(a)芘含量的不确定度分析

目的建立适用于分散式固相萃取结合高效液相色谱法测定植物油中苯并(a)芘含量的不确定度分析方法。方法样品用正己烷稀释后,加入适量吸附剂和去离子水,经分散式固相萃取净化,浓缩定容后应用Eclipse XDB-C18色谱柱(4.6 mm×150 mm,5μm)对苯并(a)芘含量进行分析,流动相以乙腈-水(v:v=88:12)进行等度洗脱,采用荧光检测器(激发波长Ex=384 nm,发射波长Em=406 nm)检测,外标法定量。依据JJF 1135-2005《化学分析测量不确定度评定》中相关规定,考查称量、定容体积、标准曲线、仪器测量重复性和回收率等引入不确定度的主要因素,并对不确定度的各分量进行计算和合成。结果当植物油中苯并(a)芘含量为4.33μg/kg时,在95%的置信区间下,其扩展不确定度为0.66μg/kg(k=2)。评定结果表明,标准曲线拟合和标准溶液的配置产生的不确定度对合成不确定度的影响较大,而样品称量所引入的不确定度较小可忽略不计。结论该评定方法客观准确,适用于分散式固相萃取结合高效液相色谱法测定植物油中苯并(a)芘含量的不确定度分析,对检测结果准确度的提高具有参考意义。     

Effects of modified atmosphere package (MAP) with a silicon gum film window and storage temperature on the quality and antioxidant system of stored Agrocybe chaxingu

Packages of Agrocybe chaxingu with or without silicon gum film windows were flushed with an initial modified atmosphere (MA) 100 mL/L O₂, 100 mL/L CO₂ and balance N₂ and stored at 1 °C and 3 °C, respectively. The changes in gas headspace, sensory, content of malondialdehyde (MDA), generation of superoxide anion, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) of mushroom were investigated. A. chaxingu stored in MAP without silicon gum film window at 1 °C had the poorest sensory quality because of chilling injury and physiological injury caused by a combination of storage temperature and poor atmosphere conditions (O₂ under 9 mL/L and CO₂ above 172 mL/L since Day 4). These injuries induced a relatively high content of MDA and generation of superoxide anion. The antioxidant enzyme system, including SOD, CAT and POD, was stimulated, to increase activities and scavenge the reactive oxygen species (ROS) to reduce injury during the initial storage period. However, these injuries also induced senescence of the stored mushroom, which resulted in decreased activities of antioxidant enzyme system. The activities of antioxidant enzyme system of A. chaxingu stored in MAP with silicon gum film window at 3 °C was the most favourable to delay the senescence process in the latter part of storage period, and the mushroom had the best quality to the end of storage.     

Improvement of the commercial quality of chilled Norway lobster (Nephrops norvegicus) stored in slurry ice: Effects of a preliminary treatment with an antimelanosic agent on enzymatic browning

The use of slurry ice is gaining increasing importance as an advanced method for the hygienic and efficient chilling and sub-zero storage of aquatic food products. In this work, this technology was applied as a novel technique for the chilling and storage of Norway lobster (Nephrops norvegicus) – a crustacean species of high-commercial value – under refrigeration conditions at −1.5 °C. In addition, the effects of a preliminary treatment with 0.5% Na HSO₃ on surface browning were evaluated and compared with the results obtained in control batches not subjected to such treatment. The processing of lobster in slurry ice significantly (p < 0.05) slowed down microbial spoilage, as determined by the counts of aerobes, psychrotrophs, proteolytic bacteria, and lactose-fermenting Enterobacteriaceae, and by the formation of volatile amines. Likewise, the autolytic breakdown mechanisms – as determined by the K value – were also significantly (p < 0.05) inhibited in the slurry ice batch. Remarkably, preliminary treatment with 0.5% sodium metabisulphite permitted better maintenance of the parameters involved in sensory quality – especially as regards the aspect of the carapace – as compared with non-treated batches, and allowed a shelf life of 9 days without surpassing the 150 mg/kg legal limit established for this food additive. On contrast, the non-treated batch stored in slurry ice exhibited a shelf life of 5 days. The combination of technological treatments proposed in this work – preliminary antimelanosic treatment and storage in slurry ice – may be successfully applied to other fresh and frozen shellfish species with a view to extending shelf life and to avoiding the legal and toxicological problems derived from current abuse of such antimelanosic agents to prevent shellfish browning.     

Influence of humic substances on the removal of pentachlorophenol by a biomimetic catalytic system with a water-soluble iron(III)-porphyrin complex

To investigate some basic aspects of soil remediation using biomimetic catalysts, the effects of humic substances (HSs) on the removal of xenobiotics, such as pentachlorophenol (PCP), were investigated. The use of a biomimetic catalytic system using tetra(p-sulfophenyl)porphine-iron(III) (Fe(III)-TPPS) and potassium monopersulfate (KHSO5) resulted in the disappearance of PCP, accompanied by dechlorination. In addition, this process was enhanced by the presence of several types of HSs. The degrees of enhancement (% delta(PCP)60) achieved by the presence of HSs from peat and compost soils were larger than those in the presence of other types of HSs (tropical peat, brown forest, and ando soils). In control experiments, no PCP disappearance and dechlorination were observed in the presence of only KHSO5, only Fe(III)-TPPS, or combinations of HSs and either KHSO5 or Fe(III)-TPPS. To better understand the role of added HS in enhancing or inhibiting PCP disappearance, correlations between the chemical parameters of the HSs and % delta(PCP)60 were investigated. The most effective HSs had lower carboxylic acid contents and lower degrees of unsaturation. The carboxylic acid content and degree of unsaturation increase with the extent of humification. Therefore, HSs of a lower degree of humification would be predicted to be more useful in enhancing the disappearance of PCP in an Fe(III)-TPPS/KHSO5 system.     

Enhanced fungal resistance of Scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) sapwood by treatment with methyltrimethoxysilane and benzalkoniumchloride

This paper presents possibilities for increasing the decay and mould resistance of Scots pine (Pinus sylvestris L.) sapwood by treatment: (1) in one step with mixtures of aqueous solutions of methyltrimethoxysilane (0, 5, 10, 20 or 30 % MTMS) and benzalkoniumchloride (0, 0.5, 1, 2 or 3 % BAC), and (2) in two steps, first with BAC and then with MTMS. Prior to fungal resistance tests, the treated and reference specimens were not or were subjected to artificial ageing in distilled water and in Xenotest, respectively. Insufficient anti-decay efficiency of MTMS against the brown-rot fungus Coniophora puteana and the white-rot fungus Trametes versicolor was improved in the presence of BAC, usually more apparent if this fungicide was used first and in higher concentrations. After both artificial ageing modes, the decay resistance of treated pine specimens decreased approximately 1.2–1.8 times. The none anti-mould efficiency of MTMS improved in the presence of BAC—significantly against the mould Penicillium brevicompactum but only minimally against the mould Aspergillus niger.