A comparative study of polychlorinated alkanes as standards for the determination of C10-C13 polychlorinated paraffines in fish samples

Fish samples of different origins have been analysed with short column gas chromatography-electron capture negative ion/mass spectrometry (SCGC/ECNI-MS). The influence of standards composed from different polychlorinated alkanes on the quantification of short chain polychlorinated paraffines (CP) was studied. Concentration values varied very differently with the response of the standards depending on their chlorination degree. The results show, that technical CP products should not be used as standard in most cases, because the composition of polychlorinated alkanes in fish is different from sample to sample.     

Synthesis of fluorinated polybrominated diphenyl ethers (F-PBDEs) as internal standards for environmental analysis

Polybrominated diphenyl ethers (PBDEs) have become widely distributed as environmental contaminants due to their wide-spread use as flame retardants. Their structural similarity to other halogenated organic pollutants, for example polychlorinated biphenyls (PCBs), has led to speculation that they may have similar toxicological properties and effects. Recent focus on PBDEs as possible priority pollutants has also led to an increasing need for reference standards of PBDEs for toxicological studies and for environmental analysis. In this work we synthesized a series of fluorinated PBDEs (F-PBDEs) which can be used as possible internal standards, as an alternative to high-cost alternatives, such as the (13)C-labelled analogues. F-PBDEs have been synthesized by using different coupling reactions and by bromination of fluorinated starting materials.     

Isomer specific synthesis using the Suzuki-coupling. Polychlorinated terphenyls as standards for environmental analysis

Defined polychlorinated terphenyl (PCT) single congeners as reference standards are the prerequisite for the development of analytical methods for their determination and quantification in the environment. The selective synthesis of PCTs for environmental analytical purposes by application of the Suzuki-coupling reaction is described. Under easily modified standard reaction conditions of this coupling process the PCTs can be obtained by reaction of benzeneboronic acids with dibromobenzenes mostly in good yields, as described by the synthesis of following PCT congeners: p-PCT (3,3("),5,5(")-tetrachloro-, 2,2("),4,4(")-tetrachloro-, 2('),3,3("),5,5(")-pentachloro-); m-PCT (3,3("),5,5(")-tetrachloro-) and o-PCT (3,3("),5,5(")-tetrachloro-). The terphenyl congeners were characterized by NMR (1H, 13C)- and FT-IR-spectroscopy. Their purity was checked by GC/MS analysis. The experimental and quantum-chemically calculated FT-IR-spectra were compared and it was shown, that the determination of the chlorine substitution pattern in the terphenyl congeners by their typical absorption spectra is possible.     

NMR and molecular modeling in environmental chemistry: prediction of 13C chemical shifts in selected C10-chloroterpenes employing DFT/GIAO theory

Accurate predictions of 13C NMR chemical shifts (standard error approximately 1.7 ppm) are achieved for a subset of chlorinated bornanes by empirical scaling of shifts from GIAO calculations with geometries obtained from HF/6-31G* calculations. The optimized molecular geometries were compared with X-ray structures for three of the toxaphene components most frequently detected in environmental samples (Parlar nos. 26, 50 and 62), and the concordance between the experimental and calculated values was found to be satisfactory. Taken overall, the results indicate that theoretical methods hold great promise for rationalizing 13C NMR chemical shifts in organohalogen compounds. However, it appeared that the DFT/GIAO shifts need to be empirically scaled to achieve good numerical agreement with experimental shifts in chlorinated bornanes. Obviously, there is a need to develop new computational methods to describe the large deshielding effects of chlorine atoms properly.     

Characterization of mass-labeled [13C14]-decabromodiphenylethane and its use as a surrogate standard in the analysis of sewage sludge samples

Very little data is available about the presence of the brominated flame retardant, DBDPE, in the environment. This study reports the characterization of [(13)C(14)]-decabromodiphenylethane and the use of this surrogate standard to positively identify and quantify the presence of DBDPE in sewage sludge samples. The large difference in response factors between BDE-209 and DBDPE predicates the use of [(13)C(14)]-decabromodiphenylethane as a surrogate standard to improve the accuracy when determining the levels of DBDPE in environmental samples.     

Inclusion of 13C12-labelled mono-, di-, and tri-chlorinated dibenzo-p-dioxin and dibenzofuran standards in US EPA methods 0023A/8290

13C12-Labelled mono-, di-, and tri-chlorinated dibenzo-p-dioxin (CDD) and chlorinated dibenzofuran (CDF) standards have been tested for their applicability to standard EPA sampling and analytical Methods 0023A/8290. These methods target for analysis only the tetra- through octa-CDD/CDF homologues. Extension of the isotope dilution method to include those lower chlorinated homologues is important toward obtaining reliable species concentration data on the complete, mono- to octa-chlorinated homologue profile. These data will improve our ability to model poly-CDD/CDF concentrations through understanding mechanisms of poly-CDD/CDF formation, chlorination, and dechlorination.     

Cost-benefit analysis as a tool for decision making in environmental projects

BACKGROUND, AIM AND SCOPE: The Damage-Function method is an efficient tool recently used in decision-making processes concerning environmental management. It is based on finding the relation between the origin of an environmental charge, and its impact on human health and the environment. The aim of the present investigation was to assess the positive impacts, also called benefits, of changes in environmental quality, and the economic viability of an industrial project on reduction of PCDD/F emissions. It has been developed with monetary criteria of two worldwide ambits: USA and European-Union countries. METHODS: The current study is a continuation of a previous investigation in which Substance Flow Analysis and Control Analysis Techniques were used to identify and to analyze all main flow values of PCDD/Fs inside the system of Tarragona Province (Spain). In the present study, Cost-Benefit Analysis (CBA) has been employed. The benefits derived from a minimization in the incidence of cancer due to a reduction in the emission of PCDD/Fs have been evaluated considering the value of a statistically saved life (VSL). Statistical analysis about uncertainty has also been incorporated. Here, the Monte Carlo simulation technique has been used. RESULTS: It is shown that CBS results depend firstly on the kind of VSL used. In fact, the differences between the decisions as a result of applying monetary criteria in USA and EU can be explained by differences between VSL values. CONCLUSION AND RECOMMENDATION: It is concluded that, for prices estimated in Euros, the emission cleaning project in the industrial plant is not feasible under any circumstance. However, although CBA seems to be a good analytical method, the final decision corresponds to the managers, who must weigh up not only the monetary criteria, but factors such as social questions.     

Collection and analysis of Nicotine as a marker for environmental tobacco smoke

Nicotine is a potential marker for environmental tobacco smoke (ETS) because it is unique to tobacco smoke and is a major constituent of the smoke. An air sampling method is presented which efficiently collects both particulate and vapor phase nicotine. Two filters are assembled in tandem in a personal sampling cassette. The first filter collects total or size fractional particules and the second is treated with sodium bisulfate to collect vapor phase nicotine and nicotine which has volatilized from the paniculate material collected on the first filler. The nicotine is then desorbed from the filters and analyzed by gas chromatography with nitrogen sensitive detection. The sampling method was evaluated in an environmental chamber under controlled conditions of temperature, humidity, ventilation and smoking rate. It was then employed in a field study of particulate exposures of railroad office workers and railroad mechanics to determine the portion of the particulate exposure attributable to environmental tobacco smoke. The method was found to be efficient and sensitive for the determination of nicotine levels in air.     

Analytical model for site-specific isotope fractionation in 13C during sorption: determination by isotopic 13C NMR spectrometry with vanillin as model compound

The aim of this study was to conceive a reactive transport model capable of providing quantitative site-specific enrichment factors for fractionation in ¹³C isotopic content during sorption. As test compound the model treats vanillin, for which the ¹³C isotopic content at natural abundance at each of the 8 carbon positions can be measured by quantitative ¹³C nuclear magnetic resonance spectrometry. This technique determines the isotope ratios with a resolution better than ±1‰ (0.1%) at each carbon position. Site-specific isotope fractionations were recorded in chromatography column experiments with silica RP-18 as stationary phase. The one dimensional reactive transport model accounted for the sorption/desorption behavior of 8 individual ¹³C-isotopomers and one ¹²C-isotopomer of vanillin and reproduced satisfactorily the bulk (average over the whole compound) fractionation observed during elution. After model calibration, the enrichment factors were fitted for each carbon site where a significant fractionation was recorded. To show the interest of such a transport model for environmental studies, the model, extended to three dimensions, was exploited to simulate reactive transport in an aquifer. These results show that significant ¹³C isotope fractionation is expected for 4 out of 8 ¹³C-isotopomers in vanillin, and illustrate that bulk isotope ratios measured by conventional compound specific isotope analysis and mass spectrometry would hardly document significant isotope fractionations in vanillin. It is concluded that modeling of site-specific isotope ratios in molecules is a priori feasible and may help to quantify unknown processes in the environment.     

环境影响评价中部分标准存在的问题及对策

环境标准是环境影响评价的准则.结合环境影响评价的实际,探讨中国主要环境标准在执行中存在的3大问题,即环境标准中控制的环境因子数远远小于企业实际生产中排放的污染因子数,简单引用《工业企业设计卫生标准》(TJ 36-79)不适合中国国情,部分因子的标准限值没有日均浓度等.针对这些问题,笔者提出利用美国环保局多介质环境模型,或根据《大气污染物综合排放标准》(GB 16297-1996)、TJ 36-79和《环境影响评价技术导则大气环境》(HJ/T 2.2-93)进行计算或推导的对策.     

Synthesis of [13C]- and [14C]-labeled phenolic humus and lignin monomers

Natural phenolic monomers are ubiquitous in the environment and are involved in the stabilization of atmospheric carbon and the transformation of xenobiotics. Investigations on the stabilization of phenolic carbons and their environmental fate are hampered by the unavailability of commercial [13C]- and [14C]-labeled phenols. Here we report the complete chemical synthesis of the lignin and humus structural monomers p-coumaric, ferulic, and caffeic acids, p-hydroxybenzaldehyde, protocatechualdehyde, vanillin, catechol, and guaiacol, uniformly [13C]- or [14C]-labeled in the aromatic ring, starting from commercially available [U-ring-13C]- or [U-ring-14C]-labeled phenol. The synthesis of these compounds involved selective ortho-hydroxylation of the aromatic ring, Friedel-Crafts alkylation, and Knoevenagel condensation. [U-ring-13C]- or [U-ring-14C]-p-coumaric acid was synthesized via p-hydroxybenzaldehyde with a 75% yield with respect to phenol. Synthesis of [U-ring-13C]- or [U-ring-14C]-ferulic acid, consisting of six single steps via guaiacol and vanillin, had an overall yield of up to 45%. Uniformly ring-labeled caffeic acid was synthesized either via catechol and protocatechualdehyde in five single steps, yielding [U-ring-14C]-caffeic acid with a 37% yield, or via guaiacol, vanillin, and ferulic acid in seven steps, yielding [U-ring-13C]-caffeic acid with an 18% yield. Ferulic acid, [14C]-labeled at beta-C of the propenoic side chain, was synthesized from [2-14C]-malonic acid under Knoevenagel conditions with a 67% yield with respect to malonic acid. Demethylation of the [beta-14C]-ferulic acid with BBr3 in CH3CN resulted in [beta-14C]-caffeic acid with a 62% yield. All [U-ring-13C]-labeled phenolic products were analyzed by 13C nuclear magnetic resonance (13C-NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS).     

The use of low-cost adsorbents for wastewater purification in mining industries

Recently, great attention has been paid to the environmental problems in mining industry. At present there are different ways of mineral processing, as well as various methods of wastewater treatment, most of them are expensive. Work is ongoing to find low-cost treatments. In this article, low-cost adsorbents, potentially useful for wastewater treatment on mining and metallurgical plants, are reviewed; their characteristics, advantages, and disadvantages of their application are compared. Also adsorption of different metals and radioactive compounds from acidic environment similar to composition of mining and metallurgical wastewaters is considered.     

The dispersion,stability, and resuspension of C60 in environmental water matrices

Environmental Science and Pollution Research - Environmental waters cover a range of water quality characteristics which could greatly affect the behavior and fate of C60 in the aquatic...     

Modification of cyclodextrin and use in environmental applications

Environmental Science and Pollution Research - Water pollution, which has become a global problem in parallel with environmental pollution, is a problem that needs to be solved urgently,...     

工业污染场地土壤中汞的化学形态及其环境限值探讨

汞是中国工业污染场地土壤中常见的重金属污染物,汞的常见形态包括单质汞、无机汞和甲基汞。比较了不同形态的汞及其化合物在物化性质、环境行为、毒性效应及致毒机制上的差异,还以美国、英国为例,探讨了针对不同形态的汞分别制定土壤环境限值的方法。最后指出,中国现有的土壤环境质量相关标准以及污染场地风险评估导则中均尚未区分汞的形态,仅给出总汞含量的限值。因此,在未来的相关标准制定中,应考虑按汞的各种形态制定不同的标准,这将更有利于客观准确评价工业污染场地土壤中汞的污染程度和环境风险。     

酸性多糖微生物絮凝剂的提取、纯化与分析

对一株链球菌发酵获得的絮凝活性物质进行了分离和提取,并应用DEAE-Sephadex A25,Sephdarose 4B凝胶色谱柱从发酵液中提取活性物质并纯化.通过薄层色谱、气相色谱、紫外光谱、红外光谱、元素分析等表征,初步推测了其主要成分为酸性多糖,其中多糖含量(73%)、糖醛酸含量(20.6%)、多糖分子量为4.3×105,可能还有少量氨基或短肽结构.     

Detection and quantification of chlordecone in contaminated soils from the French West Indies by GC-MS using the 13C10-chlordecone stable isotope as a tracer

Chlordecone is an organochlorine insecticide that has been widely used to control banana weevil in the French West Indies. As a result of this intense use, up to 20,000 ha are contaminated by this insecticide in the French West Indies, and this causes environmental damage and health problems. A scenario of exposure was drawn by French authorities, based on land usage records. Many efforts have been made to monitor the occurrence of chlordecone and its main metabolites using different analytical methods, including GC, GC/MS, LC/MS, and NIRS. Although these different methods allow for the detection and quantification of chlordecone from soils, none of them estimate the bottleneck caused by extraction of this organochlorine from soils with high adsorption ability. In this study, we used ¹³C₁₀-chlordecone as a tracer to estimate chlordecone extraction yield and to quantify chlordecone in soil extracts based on the ¹³C/¹²C isotope dilution. We report the optimization of ¹³C₁₀-chlordecone extraction from an Andosol. The method was found to be linear from 0.118 to 43 mg kg^?1 in the Andosol, with an instrumental detection limit estimated at 8.84 μg kg^?1. This method showed that chlordecone ranged from 35.4 down to 0.18 mg kg^?1 in Andosol, Nitisol, Ferralsol, and Fluvisol soil types. Traces of the metabolite β-monohydrochlordecone were detected in the Andosol, Nitisol, and Ferralsol soil samples. This last result indicates that this method could be useful to monitor the fate of chlordecone in soils of the French West Indies.