O-phenylphenol Research Articles

New approach for the determination of ortho-phenylphenol exposure by measurement of sulfate and glucuronide conjugates in urine using liquid chromatography-tandem mass spectrometry.

Ortho-phenylphenol (OPP) has been widely used as a fungicide and preservative. Although low-dose studies have demonstrated its low toxicity in animals and humans, high-dose exposure to this contaminant has toxic effects that range from skin irritation to bladder cancer. Thus far, monitoring of OPP exposure in the general population has been performed by measuring OPP after urine hydrolysis with the β-glucuronidase/arylsulfatase enzyme and sometimes by the use of a mineral acid. We developed a sensitive, accurate, and robust method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to specifically measure two-phase II OPP metabolites excreted in human urine, OPP sulfate (OPP-S), and OPP glucuronide (OPP-G). Comparative analysis of urine samples from 50 volunteers living in the Quebec City area using a direct method and phosphoric acid hydrolysis method previously developed in our laboratory showed no statistically significant difference (p value for paired t test = 0.701) in OPP concentrations. Moreover, a significant difference showed that underestimation (p value for paired t test = 0.025) occurs when β-glucuronidase/arylsulfatase enzyme deconjugation is used. The LOD achieved by the direct method permits the detection of OPP-S and OPP-G metabolites in urine at the submicrogram per liter level. Graphical abstract ᅟ.

Engineering composition-tunable 3D hierarchical bismuth oxyiodides heterojunctions: Ionic liquid-assisted fabrication with strong adsorption ability and enhanced photocatalytic properties

In this work, we report the fabrication of composition-tunable heterostructured bismuth oxyiodides photocatalysts using a facile ionic liquid-assisted precipitation method at room temperature. Through elaborately governing the reaction parameters, two groups of bismuth oxyiodide hybrids (Group 1: BiOI/Bi4O5I2, and Group 2: Bi4O5I2/Bi5O7I) with different components were prepared. The DRS spectra shows that the absorption edges of the hybrids were gradually tuned from 550 to 660 nm, which was in accordance with the color gradient from light yellow (Bi5O7I) to brick red (BiOI). The SEM images show that the products mainly exhibited 3D hierarchical architecture, which was beneficial for the adsorption of contaminants over the catalyst’s surface. The two groups of heterojunction photocatalysts all exhibited remarkably improved photocatalytic activity in decomposing o-phenylphenol (OPP) and 4-tert-butylphenol (PTBP) under visible light irradiation respect to single phase photocatalyst (BiOI, Bi4O5I2, or Bi5O7I). For BiOI/Bi4O5I2 hybrids, the S5 sample exhibited the optimal activity, which was approximately 5.35 and 1.85 times higher than that of pristine BiOI and Bi4O5I2, respectively. For the second group of Bi4O5I2/Bi5O7I, the optimal activity was observed for S9 hybrid, which was approximately 2.43 and 2.12 times higher than that of bare Bi4O5I2 and Bi5O7I under identical conditions. This activity enhancement should be attributed to the balanced band levels of the components, which facilitates the fast interfacial charge transmigration of photo-generated carriers, resulting in highly promoted charge separation efficiency. This deduction was proved by the photocurrent, electrochemical impedance spectroscopy, and photoluminescence measurements. The possible degradation mechanisms for BiOI/Bi4O5I2 and Bi4O5I2/Bi5O7I hybrids were proposed based on the band potentials and trapping experiment results.

Highly effective catalytic peroxymonosulfate activation on N-doped mesoporous carbon for o-phenylphenol degradation

As a broad-spectrum preservative, toxic o-phenylphenol (OPP) was frequently detected in aquatic environments. In this study, N-doped mesoporous carbon was prepared by a hard template method using different nitrogen precursors and carbonization temperatures (i.e., 700, 850 and 1000 °C), and was used to activate peroxymonosulfate (PMS) for OPP degradation. For comparison, mesoporous carbon (CMK-3) was also prepared. Characterization results showed that the N-doped mesoporous carbon samples prepared under different conditions were perfect replica of their template. In comparison with ethylenediamine (EDA) and dicyandiamide (DCDA) as the precursors, N-doped mesoporous carbon prepared using EDA and carbon tetrachloride as the precursors displayed a higher catalytic activity for OPP degradation. Increasing carbonization temperature of N-doped mesoporous carbon led to decreased N content and increased graphitic N content at the expense of pyridinic and pyrrolic N. Electron paramagnetic resonance (EPR) analysis showed that PMS activation on N-doped mesoporous carbon resulted in highly active species and singlet oxygen, and catalytic PMS activation for OPP degradation followed a combined radical and nonradical reaction mechanism. Increasing PMS concentration enhanced OPP degradation, while OPP degradation rate was independent on initial OPP concentration. Furthermore, the dependency of OPP degradation on PMS concentration followed the Langmuir-Hinshelwood model, reflecting that the activation of adsorbed PMS was the rate controlling step. Based on the analysis by time-of-flight mass spectrometry, the degradation pathway of OPP was proposed.

Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Direct selective hydrogenolysis of dibenzofuran (DBF) derived from coal and shale oil to a value-added chemical, ortho-phenylphenol (OPP), with high selectivity (80%) and yield (48%) has been achieved over Pt/MgO at 400 °C and 1.0 MPa by controlling the C–O bond cleavage as well as minimizing the extent of hydrogenation of aromatic rings. Meanwhile, Pt/SiO2, Pt/Al2O3, and Pt/MgO/Al2O3 catalysts were used for the DBF hydrogenolysis and showed lower selectivity for OPP. The influence of reaction parameters has been studied to unveil the optimal reaction conditions. And the phenomenon of OPP dehydrogenation is found over various catalysts for the hydrogenation reaction of OPP. Extensive reactions and catalyst characterizations demonstrated that the OPP selectivity and the dehydrogenation of OPP to DBF follows the order of supports basicity: MgO-900 > MgO > SiO2 > MgO/Al2O3 > Al2O3, which shows that the acid–base properties of supports impact the adsorption and desorption behaviors of DBF and OPP, and results...

Metabolic pathway and cell adaptation mechanisms revealed through genomic, proteomic and transcription analysis of a Sphingomonas haloaromaticamans strain degrading ortho-phenylphenol

Ortho-phenylphenol (OPP) is a fungicide contained in agro-industrial effluents produced by fruit-packaging plants. Within the frame of developing bio-strategies to detoxify these effluents, an OPP-degrading Sphingomonas haloaromaticamans strain was isolated. Proteins/genes with a putative catabolic role and bacterium adaptation mechanisms during OPP degradation were identified via genomic and proteomic analysis. Transcription analysis of all putative catabolic genes established their role in the metabolism of OPP. The formation of key transformation products was verified by chromatographic analysis. Genomic analysis identified two orthologous operons encoding the ortho-cleavage of benzoic acid (BA) (ben/cat). The second ben/cat operon was located in a 92-kb scaffold along with (i) an operon (opp) comprising genes for the transformation of OPP to BA and 2-hydroxypenta-2,4-dienoate (and genes for its transformation) and (ii) an incomplete biphenyl catabolic operon (bph). Proteomics identified 13 up-regulated catabolic proteins when S. haloaromaticamans was growing on OPP and/or BA. Transcription analysis verified the key role of the catabolic operons located in the 92-kb scaffold, and flanked by transposases, on the transformation of OPP by S. haloaromaticamans. A flavin-dependent monoxygenase (OppA1), one of the most up-regulated proteins in the OPP-growing cells, was isolated via heterologous expression and its catabolic activity was verified in vitro.

One-pot microemulsion-mediated synthesis of Bi-rich Bi4O5Br2 with controllable morphologies and excellent visible-light photocatalytic removal of pollutants

The novel Bi-rich Bi4O5Br2 with tunable morphologies of two-dimentional (2D) nanosheets (NSs), three-dimentional (3D) monodisperse layered microspheres (LMs) and hollow spheres (HSs) have been successfully synthesized via an ionic liquid-in-water (IL/W) microemulsion method. Surfactant TX-100 served as the stabilizer of the IL/W microemulsion, and its concentration significantly influenced the morphology and size of the resulting Bi4O5Br2 crystal. Possible formation mechanisms have also been discussed. UV–vis diffuse-reflectance spectra and Density function theory (DFT) calculations indicated that Bi4O5Br2 possessed stronger visible light adsorption and more negative conduction band minimum (CBM), which is beneficial to effectively activate molecular oxygen to produce O2−. The photocatalytic activity of Bi-rich Bi4O5Br2 with varied shapes was investigated and compared with BiOBr for the removal of fungicide o-phenylphenol (OPP) and antibacterial agent norfloxacin (NOR) and tetracycline hydrochloride (TC) under visible light irradiation. The as-prepared Bi4O5Br2 HSs and LMs possess higher photocatalytic efficiency than Bi4O5Br2 and BiOBr NSs, which is attributed to the hollow/layered spherical structures and Bi-rich strategies. The O2− and h+ are identified to be the major photoactive species during the photo-degradation process by scavenger experiments and EPR methods. This study is expected to provide a stepping stone to purposively design and explore other novel hollow structures with controllable morphology and enhanced photocatalytic activity.

Recovery and concentration of ortho-phenylphenol from biodesulfurization of 4-methyl dibenzothiophene by aqueous two-phase flotation

In this study we focus on recovery and concentration of ortho-phenylphenol (OPP) from fermentation broth by aqueous two-phase flotation (ATPF). The effects of pH, ammonium sulfate concentration, OPP concentration, air flow-rate, flotation time and initial volume of organic phase were evaluated on process performance using multivariate statistical methodology. Under optimal conditions, the separation efficiency (E%), the concentration coefficient (α) and the distribution coefficient (D) for ATPF reached 57.55%, 4.23 and 9.86, respectively. When compared to others conventional techniques also used in this work, such as aqueous two-phase extraction, solvent sublation and liquid-liquid extraction, the ATPF showed better performance in terms of E%, α and D. Additionally, experiments carried out with fermentation broth derived from the biodesulfurization of 4-MDBT have shown promise in the recovery and concentration of OPP. In summary, the results indicated that the ATPF is an effective separation technique in the pretreatment of the OPP from bona fide mixtures.

Pharmacokinetics of 14 C-ortho-phenylphenol following intravenous administration in pigs.

Workers in the USA are exposed to industrial formulations, which may be toxic. These formulations often contain preservatives or biocides such as ortho-phenylphenol (OPP). There are limited data describing OPP following intravenous administration to assess truly the clearance of this chemical in humans and other species. In vivo experiments were conducted in pigs to determine related pharmacokinetic parameters. 14 C-OPP was administered as an intravenous bolus dose. Blood, feces, urine and tissue samples were collected for analysis by liquid scintillation. Data were analyzed using non-compartmental and compartmental pharmacokinetic model approaches. These data fitted a three-compartment model and showed that the half-life of 14 C-OPP following the intravenous bolus in pigs was 46.26 ± 10.01 h. The kidneys play a crucial role in clearance of 14 C-OPP with a large percentage of the dose being found in the urine (70.3 ± 6.9% dose). Comparisons with other species suggest that 14 C-OPP clearance in pigs (2.48 ml h-1 kg-1 ) is less than that in humans (18.87 ml h-1 kg-1 ) and rats (35.51 ml h-1 kg-1 ). Copyright © 2016 John Wiley & Sons, Ltd.

Simultaneous Determination of Seven Kinds of Fungicides in Citrus Fruits by Gas Chromatograghy/Mass Spectrometry.

A simple and accurate procedure was developed for the determination of seven fungicides, azoxystrobin (AZO), diphenyl (DP), fludioxonil (FLUDI), imazalil (IMZ), o-phenylphenol (OPP), pyrimethanil (PYRI) and thiabendazole (TBZ), in citrus fruits. The citrus fruit sample was extracted with acetonitrile and cleaned up with a graphite carbon/aminopropyl silanized silica gel solid-phase extraction cartridge using acetonitrile-toluene (3 : 1, v/v) as the eluent. Triphenylene was used as an internal standard (I.S.) at the concentration of 0.5 μg/mL. The sample solution was subjected to GC-MS utilizing the matrix-matched standard solution method. The recoveries of AZO, FLUDI, IMZ, OPP, PYRI and TBZ spiked in domestic citrus fruits (Satsuma mandarin) at the level of 0.01-10.0 μg/g were 72.8-104% and the limits of quantification were 0.01 μg/g. The recoveries of DP spiked in domestic citrus fruits at the level of 0.01-70.0 μg/g were 70.8-80.4% and the limit of quantification was 0.01 μg/g. The proposed method was applied to the determination of fungicides in citrus fruits purchased in various markets.

Effects of innovative and conventional sanitizing treatments on the reduction of Saccharomycopsis fibuligera defects on industrial durum wheat bread

Wickerhamomyces anomalus, Hyphopichia burtonii and Saccharomycopsis fibuligera are spoilage yeasts causing chalk mold defects on sliced bread packaged under modified atmosphere. The first objective of this study, carried out in a bread-making company for two consecutive years, was to genetically identify yeasts isolated from spoiled sliced bread in Modified Atmosphere Packaging (MAP) and to determine the dominant species among identified strains. The second objective was to evaluate the effects of hydrogen peroxide and silver solution 12% (HPS) treatment in the leavening cells and cooling chambers, in comparison with the conventional Ortho-Phenylphenol (OPP) fumigating treatment, on the incidence of chalk defects of the commercialized products. One-hundred percent of the isolated yeasts were identified as S. fibuligera, while H. burtonii and W. anomalus were not detected. Concerning mean water activity (aw) and moisture content values, packaged bread samples were, respectively, included in the range 0.922–0.940 and 33.40–35.39%. S. fibuligera was able to grow in a wide range of temperature (11.5 to 28.5°C) and relative humidity (70.00 to 80.17%) in the processing environments, and product aw<0.94. Compared to OPP, the combined treatment with hydrogen peroxide and silver solution, in association with MAP, reduced to a negligible level yeast contamination of industrial sliced bread. The identification of the spoilage organisms and a comprehensive understanding of the combined effects of aw, pO2/pCO2 inside the packages, environmental conditions and sanitizing treatment on the growth behaviour is essential for future development of adequate preventive process strategies against chalk mold defects.

Cu/Mg/Al hydrotalcite-like hydroxide catalysts for o-phenylphenol synthesis

Cu-Mg-Al layered double hydroxides with different amounts of Cu were prepared by the hydrothermal crystallization method. The samples were characterized by XRD and SEM, which confirmed the formation of layered double hydroxides phase. The hydrotalcite materials and their calcined counterparts are further characterized by FT-IR, thermogravimetric, N2 adsorption-desorption, CO2-TPD and temperature-programmed reduction with H2. The Cu/Mg/Al mixed oxide catalysts obtained via thermal decomposition of hydroxides precursor, were used for dehydrogenation of 2-(1-cyclohexenyl). The catalytic measurements conclude that the selectivity to ortho-phenylphenol (OPP) depends on the dispersion of cooper for these catalysts.

Opinion of the Scientific Committee on Consumer Safety (SCCS) – Revision of the opinion on o-Phenylphenol, Sodium o-phenylphenate and Potassium o-phenylphenate (OPP), in cosmetic products

o-Phenylphenol, Sodium o-phenylphenate, Potassium o-phenylphenate, CAS n. 90-43-7, 132-27-4, 13707-65-8 as preservatives are regulated in Annex V/7 of the Cosmetics Regulation (EC) n. 1223/2009 at a maximum concentration of 0.2% (as phenol).In February 2013, the Commission received a risk assessment submitted by the French Agency ANSM (Agence nationale de sécurité des médicaments et des produits de santé) which rose concerns about the use of o-Phenylphenol as preservatives in cosmetic products.In the context of the ANSM report (Evaluation du risque lié à l'utilisation de l'orthophénylphénol CAS n. 90-43-7 dans les produits cosmétiques) o-Phenylphenol has been identified as likely to be an endocrine disruptor. The report concludes that the maximum authorised concentration (currently of 0.2%) of o-Phenylphenol for use as a preservative should be revised due to low margin of safety.In January 2014, in response to a call for data on o-Phenylphenol by the Commission, Industry submitted a safety dossier in order to defend the current use of o-Phenylphenol, Sodium o-phenylphenate, Potassium o-phenylphenate, CAS n. 90-43-7, 132-27-4, 13707- 65-8 as preservatives in cosmetic formulations at a maximum concentration of 0.2% (as phenol).o-Phenylphenol as preservative with a maximum concentration of 0.2% in leave-on cosmetic products is not safe. Also, in view of further exposures including noncosmetic uses (see Anses, 2014), the maximum concentration of o-Phenylphenol in leave-on cosmetic products should be lowered. However, the proposed maximum use concentration of up to 0.15% by the applicant can be considered safe.The use of o-Phenylphenol as preservative with a maximum concentration of 0.2% in rinse-off cosmetic products is considered safe.Based on the information provided, no conclusions of safe use can be drawn for Sodium o-phenylphenate and Potassium o-phenylphenate.In vitro data indicate an absent or very weak binding affinity of OPP to the oestrogen receptor, in line with limited stimulation of proliferation in oestrogen responsive cells.No information is available on androgenic and anti-androgenic effects of OPP in vitro.Agonistic or antagonistic effects on thyroid hormones were not observed with OPP.There might be a potential of injury to the vision system attributable to OPP.Aggregate exposure to OPP should be considered.

The role of urinary pH in o-phenylphenol-induced cytotoxicity and chromosomal damage in the bladders of F344 rats.

o-Phenylphenol (OPP) is a widely used fungicide and antibacterial agent that at high doses has been shown to cause bladder cancer in male F344 rats. The mechanisms underlying OPP-induced bladder carcinogenicity remain unclear but it has been proposed that a non-enzymatic pH-dependent autoxidation of phenylhydroquinone (PHQ), a primary metabolite of OPP, may be a key step in OPP-induced rat bladder carcinogenesis. To investigate this mechanism and to provide insights into the potential human health relevance of OPP-induced cancer, a series of in vitro and in vivo experiments were conducted. In human lymphoblastoid TK-6 cells and rat bladder epithelial NBT-II cells, strong increases in cytotoxicity were seen at a constant concentration of PHQ by increasing the buffer pH as well as by increasing concentrations of PHQ at a constant pH. In in vivo studies, male rats were administered OPP (4,000 and 8,000 ppm) in a diet supplemented with either 1% ammonium chloride or 3% sodium bicarbonate to produce acidic and alkaline urinary pH, respectively. Significant increases in cell proliferation as detected by 5-bromo-2'-deoxyuridine incorporation and micronucleus formation were seen in the bladder cells of OPP-treated rats with neutral or alkaline urinary pH but not in animals with the acidified urine. The results from these in vitro and in vivo studies provide support for the autoxidation hypothesis of bioactivation, and provide additional evidence that urinary pH can significantly influence the genotoxicity and carcinogenicity of this important agent.

Improvement in the anti-abrasion behavior of a highly refractive optical sheet through the use of modified urethane acrylates

The back light unit (BLU) is the core component of LCDs for laptops, mobile phones, navigation, large televisions, and public information displays (PIDs). To enhance the optical efficiency of LCDs, optical films with a high reflective index have been used for BLUs. Highly reflective chemicals have been actively investigated to enhance the optical efficiency and mechanical property of BLUs. In this study, urethane acrylates were modified to improve the anti-abrasion behavior of highly refractive materials. Highly refractive modified urethane acrylate (MUA) was synthesized from o-phenylphenol (OPP), polyols, and diisocyanate. The refractive index of ester-based o-phenylphenol urethane acrylates (OPPUAs) was slightly greater than that of ether-based OPPUAs. The difference was due to the electron density increase induced by molecular interactions in the ester polyol, resulting in a higher refractive index. Additionally, urethane acrylate with carbonate polyol showed the highest viscosity. Based on the anti-abrasion test, the weight loss of MUAs with an alkyl group was less than that in OPPUAs with an aromatic group.

The potential of organic substrates based on mushroom substrate and straw to dissipate fungicides contained in effluents from the fruit-packaging industry – Is there a role for Pleurotus ostreatus?

Citrus fruit-packaging plants (FPP) produce large wastewater volumes with high loads of fungicides like ortho-phenylphenol (OPP) and imazalil (IMZ). No methods are in place for the treatment of those effluents and biobeds appear as a viable alternative. We employed a column study to investigate the potential of spent mushroom substrate (SMS) of Pleurotus ostreatus, either alone or in mixture with straw and soil plus a mixture of straw /soil to retain and dissipate IMZ and OPP. The role of P. ostreatus on fungicides dissipation was also investigated by studying in parallel the performance of fresh mushroom substrate of P. ostreatus (FMS) and measuring lignolytic enzymatic activity in the leachates. All substrates effectively reduced the leaching of OPP and IMZ which corresponded to 0.014–1.1% and 0.120–0.420% of their initial amounts respectively. Mass balance analysis revealed that FMS and SMS/Straw/Soil (50/25/25 by vol) offered the most efficient removal of OPP and IMZ from wastewaters respectively. Regardless of the substrate, OPP was restricted in the top 0–20cm of the columns and was bioavailable (extractable with water), compared to IMZ which was less bioavailable (extractable with acetonitrile) but diffused at deeper layers (20–50, 50–80cm) in the SMS- and Straw/Soil-columns. PLFAs showed that fungal abundance was significantly lower in the top layer of all substrates from where the highest pesticide amounts were recovered suggesting an inhibitory effect of fungicides on total fungi in the substrates tested. Our data suggest that biobeds packed with SMS-rich substrates could ensure the efficient removal of IMZ and OPP from wastewaters of citrus FPP.

Land Spreading of Wastewaters from the Fruit-Packaging Industry and Potential Effects on Soil Microbes: Effects of the Antioxidant Ethoxyquin and Its Metabolites on Ammonia Oxidizers.

Thiabendazole (TBZ), imazalil (IMZ), ortho-phenylphenol (OPP), diphenylamine (DPA), and ethoxyquin (EQ) are used in fruit-packaging plants (FPP) with the stipulation that wastewaters produced by their application would be depurated on site. However, no such treatment systems are currently in place, leading FPP to dispose of their effluents in agricultural land. We investigated the dissipation of those pesticides and their impact on soil microbes known to have a key role on ecosystem functioning. OPP and DPA showed limited persistence (50% dissipation time [DT50], 0.6 and 1.3 days) compared to TBZ and IMZ (DT50, 47.0 and 150.8 days). EQ was rapidly transformed to the short-lived quinone imine (QI) (major metabolite) and the more persistent 2,4-dimethyl-6-ethoxyquinoline (EQNL) (minor metabolite). EQ and OPP exerted significant inhibition of potential nitrification, with the effect of the former being more persistent. This was not reflected in the abundance (determined by quantitative PCR [qPCR]) of the amoA gene of ammonia-oxidizing bacteria (AOB) and archaea (AOA). Considering the above discrepancy and the metabolic pattern of EQ, we further investigated the hypothesis that its metabolites and not only EQ were toxic to ammonia oxidizers. Potential nitrification, amoA gene abundance, and amoA gene transcripts of AOB and AOA showed that QI was probably responsible for the inhibition of nitrification. Our findings have serious ecological and practical implications for soil productivity and N conservation in agriculturally impacted ecosystems and stress the need to include metabolites and RNA-based methods when the soil microbial toxicity of pesticides is assessed.

Isolation of a diphenylamine-degrading bacterium and characterization of its metabolic capacities, bioremediation and bioaugmentation potential.

The antioxidant diphenylamine (DPA) is used in fruit-packaging plants for the control of the physiological disorder apple scald. Its use results in the production of DPA-contaminated wastewater which should be treated before finally discharged. Biological treatment systems using tailored-made microbial inocula with specific catabolic activities comprise an appealing and sustainable solution. This study aimed to isolate DPA-degrading bacteria, identify the metabolic pathway of DPA and evaluate their potential for future implementation in bioremediation and biodepuration applications. A Pseudomonas putida strain named DPA1 able to rapidly degrade and utilize DPA as the sole C and N source was enriched from a DPA-contaminated soil. The isolated strain degraded spillage-level concentrations of DPA in liquid culture (2000 mg L(-1)) and in contaminated soil (1000 mg kg(-1)) and metabolized DPA via the transient formation of aniline and catechol. Further evidence for the bioremediation and biodepuration potential of the P. putida strain DPA1 was provided by its capacity to degrade the post-harvest fungicide ortho-phenylphenol (OPP), concurrently used by the fruit-packaging plants, although at slower rates and DPA in a wide range of pH (4.5-9) and temperatures (15-37 °C). These findings revealed the high potential of the P. putida strain DPA1 for use in future soil bioremediation strategies and/or as start-up inocula in wastewater biodepuration systems.

Dissipation, metabolism and sorption of pesticides used in fruit-packaging plants: Towards an optimized depuration of their pesticide-contaminated agro-industrial effluents

Wastewaters from the fruit-packaging industry constitute a serious point source contamination with pesticides. In the absence of effective depuration methods, they are discharged in municipal wastewater treatment plants or spread to land. Modified biobeds could be an applicable solution for their treatment. We studied the dissipation of thiabendazole (TBZ), imazalil (IMZ), ortho-phenylphenol (OPP), diphenylamine (DPA) and ethoxyquin (EQ), used by the fruit-packaging industry, in anaerobically digested sewage sludge, liquid aerobic sewage sludge and in various organic substrates (biobeds packing materials) composed of soil, straw and spend mushroom substrate (SMS) in various volumetric ratios. Pesticide sorption was also determined. TBZ and IMZ showed higher persistence especially in the anaerobically digested sewage sludge (DT50=32.3–257.6d), in contrast to OPP and DPA which were rapidly dissipated especially in liquid aerobic sewage sludge (DT50=1.3–9.3d). EQ was rapidly oxidized mainly to quinone imine (QI) which did not persist and dimethyl ethoxyquinoline (EQNL, minor metabolite) which persisted for longer. Sterilization of liquid aerobic sewage sludge inhibited pesticide decay verifying the microbial nature of pesticide dissipation. Organic substrates rich in SMS showed the highest dissipation capacity with TBZ and IMZ DT50s of ca. 28d compared to DT50s of >50d in the other substrates. TBZ and IMZ showed the highest sorption affinity, whereas OPP and DPA were weakly sorbed. Our findings suggest that current disposal practices could not guarantee an efficient depuration of effluents from the fruit-packaging industry, whereas SMS-rich biobed organic substrates show efficient depuration of effluents from the fruit-packaging industry via accelerated dissipation even of recalcitrant fungicides.

Liquid waveguide spectrophotometric measurement of nanomolar ammonium in seawater based on the indophenol reaction with o-phenylphenol (OPP)

We describe a highly sensitive colorimetric method for the determination of nanomolar concentrations of ammonium in seawater based on the indophenol reaction with o-phenylphenol [(1,1′-biphenyl)-2-ol, abbreviated as OPP]. OPP is available as non-toxic, stable flaky crystals with no caustic odor and has some advantages over phenol in practical use. The method was established by using a gas-segmented continuous flow analyzer equipped with two types of long path liquid waveguide capillary cell, LWCCs (100cm and 200cm) and an UltraPath (200cm), which have inner diameters of 0.55mm and 2mm, respectively. The reagent concentrations, flow rates of the pumping tubes, and reaction path and temperature were determined on the basis of a manual indophenol blue method with OPP (Kanda, Water Res. 29 (1995) 2746–2750). The sample mixed with reagents that form indophenol blue dye was measured at 670nm. Aged subtropical surface water was used as a blank, a matrix of standards, and the carrier. The detection limits of the analytical systems with a 100cm LWCC, a 200cm LWCC, and a 200cm UltraPath were 6, 4, and 4nM, respectively. These systems had high precision (<4% at 100nM) and a linear dynamic range up to 200nM. Non-linear baseline drift did not occur when using the UltraPath system. This is due to the elimination of cell clogging because of the larger inner diameter of the UltraPath compared to the LWCCs. The UltraPath system is thus more suitable for long-term measurements compared with the LWCC systems. The results of the proposed sensitive colorimetry and a conventional colorimetry for the determination of seawater samples showed no significant difference. The proposed analytical systems were applied to underway surface monitoring and vertical observation in the oligotrophic South Pacific.

Isolation and characterisation of a Sphingomonas strain able to degrade the fungicide ortho-phenylphenol.

Ortho-phenylphenol (OPP) is a fungicide used in fruit packaging plants for the control of fungal infestations during storage. Its application leads to the production of large wastewater volumes which according to the European legislation should be treated on site. In spite of this, no efficient treatment systems are currently available, and the development of biological systems based on tailored-made pesticide-degrading inocula for the treatment of these wastewaters is an appealing solution. Enrichment cultures from a soil collected from a wastewater disposal site resulted in the isolation of a pure Sphingomonas haloaromaticamans strain P3 able to degrade rapidly OPP and use it as an energy source. Its degrading capacity was dependent on the external supply of amino acids or on the presence of other bacteria that did not contribute to fungicide degradation. The isolated S. haloaromaticamans strain was able to metabolise up to 150 mg L(-1) of OPP within 7 days, in a wide range of pH (4.5-9) and temperatures (4-37 °C), and in the presence of other pesticides (thiabendazole and diphenylamine) co-used in the fruit packaging industry. Overall, the OPP-degrading bacterium isolated showed high potential for use in future biodepuration treatment systems and bioremediation strategies.