Transformation of tetrabromobisphenol A in the presence of different solvents and metals

Solvent-based separation method is presumably an efficient and environmentally beneficial approach for elimination of brominated flame retardants (BFRs) from waste electrical and electronic equipment (WEEE). The overall goal of this study was to evaluate possible effects of organic solvent on the behavior of BFRs during solvent-based processing of WEEE. We initiated a set of batch experiments for examining the rates and possible pathways of transformation of a representative BFR (tetrabromobisphenol A, TBBPA) using acetone, toluene, and methanol as the solvents. Our results showed that toluene and methanol had no effect on the transformation of TBBPA, but approximately 20% of TBBPA (100 mg L⁻¹) was transformed by acetone within 2 h at 50 °C. Analysis of the products with GC-MS showed that two high-molecular-weight products (MW = 586) were major products of the transformation reactions. The role of acetone as a reactant in the transformation of TBBPA was further validated with dueterated acetone. In addition, the effects of co-existing metals in WEEE (i.e., Zn, Cu, and Ni) on the transformation of TBBPA in the solvent systems were investigated. These metals tested were found to greatly enhance the rates of TBBPA transformation. The metal facilitated solvent reactions with TBBPA may lower the extractability of TBBPA by formation of larger and less soluble products, hence potentially increasing the cost for separating the chemical from WEEE.     

Kinetics and pathways for the debromination of polybrominated diphenyl ethers by bimetallic and nanoscale zerovalent iron: effects of particle properties and catalyst

Polybrominated diphenyl ethers (PBDEs) are recognized as a new class of widely-distributed and persistent contaminants for which effective treatment and remediation technologies are needed. In this study, two kinds of commercially available nanoscale Fe⁰ slurries (Nanofer N25 and N25S), a freeze-dried laboratory-synthesized Fe⁰ nanoparticle (nZVI), and their palladized forms were used to investigate the effect of particle properties and catalyst on PBDE debromination kinetics and pathways. Nanofers and their palladized forms were found to debrominate PBDEs effectively. The laboratory-synthesized Fe⁰ nanoparticles also debrominated PBDEs, but were slower due to deactivation by the freeze-drying and stabilization processes in the laboratory synthesis. An organic modifier, polyacrylic acid (PAA), bound on N25S slowed PBDE debromination by a factor of three to four compared to N25. The activity of palladized nZVI (nZVI/Pd) was optimized at 0.3 Pd/Fe wt% in our system. N25 could debrominate selected environmentally-abundant PBDEs, including BDE 209, 183, 153, 99, and 47, to end products di-BDEs, mono-BDEs and diphenyl ether (DE) in one week, while nZVI/Pd (0.3 Pd/Fe wt%) mainly resulted in DE as a final product. Step-wise major PBDE debromination pathways by unamended and palladized Fe⁰ are described and compared. Surface precursor complex formation is an important limiting factor for palladized Fe⁰ reduction as demonstrated by PBDE pathways where steric hindrance and rapid sequential debromination of adjacent bromines play an important role.     

Effect of diurnal changes in VOC source strengths on performances of receptor models

Introduction

The effect of diurnal changes in strengths of volatile organic compound (VOC) sources on the performances of positive matrix factorization (PMF) and principal component analysis (PCA) was investigated using ambient measurement results that were taken during daytime and nighttime hours between March 24 and May 14, 2011, within Davutpasa Campus of Yildiz Technical University (Istanbul, Turkey).

Methods

Forty-five VOC species, ranging from C₅ to C₁₁ in volatility, were measured in the samples, 40 of which are included in the analyses. Ambient samples were grouped as daytime, nighttime, and all day datasets, and both PMF and PCA were applied to each dataset. A total of six source groups were extracted from each dataset: solvent use, general industrial paint use, gasoline and diesel vehicle exhausts, and biogenic as well as evaporative emissions. Estimated source contributions showed great diurnal variations.

Results

The results suggested that extraction of possible sources by PCA depends greatly on the number of samples and the strength of the sources, while PMF produced stable results regardless of number of samples and source strengths.

Conclusion

Although PMF was unable to resolve gasoline vehicle and evaporative emissions, it was found to be successful in explaining diurnal fluctuations in source strengths, while the performance of PCA depends on the strength of emission source.     

Identification of relevant micropollutants in Austrian municipal wastewater and their behaviour during wastewater treatment

The European Union has defined environmental quality standards (EQSs) for surface waters for priority substances and several other pollutants. Furthermore national EQSs for several chemicals are valid in Austria. The study investigated the occurrence of these compounds in municipal wastewater treatment plant (WWTP) effluents. In a first screening of 15 WWTPs relevant substances were identified, which subsequently were monitored in 9 WWTPs over 1 year (every 2 months). Out of 77 substances or groups of substances (including more than 90 substances) 13 were identified as potentially relevant in respect to water pollution and subjected to the monitoring, whereas most other compounds were detected in concentrations far below the respective EQS for surface waters and therefore not further considered. The preselected 13 compounds for monitoring were cadmium (Cd), nickel (Ni), copper (Cu), selenium (Se), zinc (Zn), diuron, polybrominated diphenyl ethers (PBDEs), di(ethyl-hydroxyl)phthalate (DEHP), tributyltin compounds (TBT), nonylphenoles (NP), adsorbable organic halogens (AOX) and the complexing agents ethylenediaminetetraacetic acid (EDTA) as well as nitrilotriacetic acid (NTA). In the effluents of WWTPs the concentrations of the priority substances Cd, NP, TBT and diuron frequently exceeded the respective EQS, whereas the concentrations for DEHP and Ni were below the respective EQS. The effluent concentrations for AOX, EDTA, NTA, Cu, Se and Zn frequently are in the range or above the Austrian EQS for surface waters. Besides diuron and EDTA all compounds are removed at least partially during wastewater treatment and for most substances the removal via the excess sludge is the major removal pathway. For the 13 compounds which were monitored in WWTP effluents population equivalent specific discharges were calculated. Since for many compounds no or only few information is available, these population equivalent specific discharges can be used to assess emissions from municipal WWTPs to surface waters as well as to make a first assessment of the impact of a discharge on surface waters chemical status. Comparing discharges and river pollution on a load basis, the influence of diffuse sources becomes obvious and therefore should also be taken into consideration in river management.     

Benthic community structure, diversity, and productivity in the shallow Barents Sea bank (Svalbard Bank)

The Barents Sea is among the most productive areas in the world oceans, and its shallow banks exhibit particularly high rates of primary productivity reaching over 300 g C m^?2year^?1. Our study focused on the Svalbard Bank, an important feeding area for fishes and whales. In order to investigate how benthic community structure and benthic secondary production vary across environmental gradients and through time, we sampled across the bank and compared results with a similar study conducted 85 years ago. Considerable variability in community structure and function across bank corresponded with differences in the physical structure of the habitat, including currents, sedimentation regimes and sediment type, and overlying water masses. Despite an intensive scallop fishery and climatic shifts that have taken place since the last survey in the 1920s, benthic community structure was very similar to that from the previous survey, suggesting strong system resilience. Primary and secondary production over shallow banks plays a large role in the Barents Sea and may act as a carbon subsidy to surrounding fish populations, of which many are of commercial importance.     

Determination of heavy metals and metals levels in five fish species from I??kl? Dam Lake and Karaca?ren Dam Lake (Turkey)

The concentrations of heavy metals and metals (Zn, Pb, Bi, Cd, Ni, Co, Fe, Mn, Mg, Cu, Cr, Ca, Sr, Na, Li, K) were measured in muscle of five species Cyprinus carpio (from I??kl? dam), Scardinius erythrophthalmus (from I??kl? dam), Tinca tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), Carassius carassius (from Karaca?ren dam) caught from I??kl? and Karaca?ren. The highest metal was Na (466.95 μg/g) in C. carassius, while the lowest levels were Fe (0.37 μg/g) and Cu (0.37 μg/g) in C. carpio from I??kl? dam. The mean concentrations μg/g d.w. some of heavy metals in muscle of C. carpio (from I??kl? dam), S. erythrophthalmus (from I??kl? dam), T. tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), C. carassius (from Karaca?ren dam) were as follows: Cd 2.00-2.10-1.95-2.06-2.27, Zn 4.36-2.64-13.13-13.33-24.47, Pb 1.65-1.24-1.90-2.37-2.41, Co 2.46-2.37-2.48-2.58-2.80, Mg 138.51-154.35-218.59-204.58-202.16, Fe 0.37-2.62-3.17-3.01-12.33, respectively.     

Estimating the aquatic emissions and fate of perfluorooctane sulfonate (PFOS) into the river Rhine

The sources, distribution, levels and sinks of perfluorooctane sulfonate (PFOS) estimated to be released from areas of high population density, have been explored using the river Rhine as a case study. A comparison between modelled and measured data is presented, along with analysis of the importance of PFOS sorption in riverine systems. PFOS releases into the Rhine were estimated to be 325-690 kg/yr based on per capita emission rates of 27-57 μg day(-1) from a population of 33 million living within a 50 km zone either side of the river. Sorption of PFOS to suspended particles and sediments may alter its fate in the aquatic environment. Therefore available measured and modelled partitioning data was assessed, and K(d) values (sorption coefficient) of 7.5 and 20 were selected. This resulted in sediment-water ratios of 23-76 : 1, which are similar to ratios reported in the literature, and resulted in modelled estimates that <20% of the total PFOS entering the Rhine binds to sediments or suspended particles. The calculated discharge from the Rhine to the North Sea based on measured data was 420-2200 kg/yr; our model predictions are in good agreement with these estimates. Emission trends were accurately predicted, suggesting population density can be effectively used as a surrogate for diffuse PFOS emissions from product use, while predicted concentrations were a factor of 2-4 below measured data showing the importance of other sources. Transfer of PFOS to sediment is estimated to be minimal, and consequently discharges to the North Sea are roughly equal to PFOS releases to river water.     

芘高效降解菌ZQ_5的培养条件及无机元素对其降解效率的影响

以从我国最大的石油污水灌区之一——沈抚灌区污染土壤分离到的以芘为惟一碳源、能源生长的高效降解菌株ZQ5为实验材料,通过对菌株ZQ5培养条件的优化,以及采用摇瓶振荡培养方法测定菌株ZQ5对不同浓度芘的降解率,表明：菌株ZQ5在30℃振荡培养16 d后对150 mg/L芘的降解率为90.31%。通过模拟稻田施用N、P和K肥等的土壤环境,探索了无机营养元素对降解菌ZQ5降解能力的影响,发现土壤中混合加入N、P和K无机营养元素的降解率能达到82%以上,比单加某种营养元素对降解菌ZQ5的降解效果好。本研究结果可以指导稻田PAHs的原位生物修复。     

Novel imazethapyr detoxification applying advanced oxidation processes

Different degradation methods have been applied to assess the suitability of advanced oxidation process (AOPs) to promote mineralization of imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid], a widely used imidazolinone class herbicide, the persistence of which has been demonstrated in surface and ground waters destined to human uses. Independent of the oxidation process assessed, the decomposition of imazethapyr always followed a pseudo-first order kinetic. The direct UV-irradiation (UV) of the herbicide as well as its oxidation with ozone (O?), and hydrogen peroxide tied to UV-irradiation (H?O?/UV) were sufficiently slow to permit the identification of intermediate products, the formation pathway of which has been proposed. Ozonation joined to UV-irradiation (O?/UV), ozonation joined to titanium dioxide photo-catalysis (TiO?/UV+O?), sole photo-catalysis (TiO?/UV), and photo-catalysis reinforced with hydrogen peroxide-oxidation (TiO?/UV+H?O?) were characterized by a faster degradation and rapid formation of a lot of small molecules, which were quickly degraded to complete mineralization. The most effective oxidation methods were those using titanium dioxide photo-catalysis enhanced either by ozonation or hydrogen peroxide. Most of all, these last processes were useful to avoid the development of dangerous by-products.     

Beyond selectivity: Are behavioral avoidance and hormesis likely causes of pyrethroid-induced outbreaks of the southern red mite Oligonychus ilicis?

Secondary pest outbreak is a counterintuitive ecological backlash of pesticide use in agriculture that takes place with the increase in abundance of a non-targeted pest species after pesticide application against a targeted pest species. Although the phenomenon was well recognized, its alternative causes are seldom considered. Outbreaks of the southern red mite Oligonychus ilicis are frequently reported in Brazilian coffee farms after the application of pyrethroid insecticides against the coffee leaf miner Leucoptera coffeella. Selectivity favoring the red mite against its main predatory mites is generally assumed as the outbreak cause, but this theory has never been tested. Here, we assessed the toxicity (and thus the selectivity) of deltamethrin against both mite species: the southern red mite and its phytoseid predator Amblyseius herbicolus. Additionally, behavioral avoidance and deltamethrin-induced hormesis were also tested as potential causes of red mite outbreak using free-choice behavioral walking bioassays with the predatory mite and life-table experiments with both mite species, respectively. Lethal toxicity bioassays indicated that the predatory mite was slightly more susceptible than its prey (1.5×), but in more robust demographic bioassays, the predator was three times more tolerant to deltamethrin than its prey, indicating that predator susceptibility to deltamethrin is not a cause of the reported outbreaks. The predator did not exhibit behavioral avoidance to deltamethrin; however insecticide-induced hormesis in the red mite led to its high population increase under low doses, which was not observed for the predatory mite. Therefore, deltamethrin-induced hormesis is a likely cause of the reported red mite outbreaks.