Organochlorine pesticides and polychlorinated biphenyl residues in reared and wild Dicentrarchus labrax from the Mediterranean Sea (Sicily, Italy)

The aim of this research was to compare the levels of organochlorine pesticides and PCBs in samples of Dicentrarchus labrax living in the Straits of Messina with samples cultivated in cages in the Mediterranean Sea. Muscles and liver tissues sampled over the months, within the same year, were analyzed. The quantitative determination of the organochlorine compounds was performed by GC-ECD and confirmed with GC–MS. The results showed that the concentrations of DDTs in muscles and livers as such of reared sea bass were in the range 0.2–1.3 μg/kg and 9.6 –48.4 μg/kg, respectively. In wild fish the concentrations of DDTs were very much lower: 0.1 μg/kg in muscles, 5.1–9.0 μg/kg in livers. Total PCBs levels were higher in cultivated sea bass than in wild fish; the concentration ranges were 5.3–59.7 μg/kg and 74.4–267.4 μg/kg in muscle and liver of reared samples, respectively, and 1.1–1.5 μg/kg and 63.2–109.4 μg/kg in muscle and liver of wild samples, respectively.     

基于空气质量自动监测站PM10滤纸的新型大气二NFDA1英监测技术研究

通过典型空气质量自动监测站PM10滤纸(结合气固相分配模拟)和传统大流量大气采样仪的比对试验,探讨了基于空气质量自动监测站PM10滤纸的新型大气二英监测技术的可行性。研究表明,基于空气质量自动监测站PM10滤纸的大气固相二英毒性当量浓度和指纹特征与传统大流量大气监测技术的监测结果具有很好的可比性;基于空气质量自动监测站PM10滤纸气固相分配模拟(利用Harner-Bidleman模型)的大气二英毒性当量浓度和指纹特征与传统大流量大气监测技术的监测结果具有很好的可比性。与传统大流量大气监测技术相比,基于空气质量自动监测站PM10滤纸的新型大气二英监测技术可以利用现有的大气自动监测网络和气固相分配模型,具有采样成本低、代表性强和易于普及等优点,适合不同区域尺度大气二英的长期同步监测。     

PCDD/Fs-induced oxidative damage and antioxidant system responses in tobacco cell suspension cultures

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are ubiquitous contaminants and can be considerably accumulated by natural plants. In order to elucidate the biochemical and physiological responses of plant to PCDD/Fs, tobacco Bright Yellow-2 (BY-2) cells were selected as model plant and treated with time- and concentration-dependent PCDD/Fs. The toxic effect and oxidative stress caused by PCDD/Fs were evident, which could be indicted by the reduction in fresh mass, the increase in malondialdehyde (MDA) content, and the damage of tobacco cell ultrastructure. PCDD/Fs tolerance was correlated with changes in antioxidant system and hormones of tobacco cells. Superoxide dismutase (SOD) and peroxidase (POD) exhibited peak enzyme activities at the PCDD/Fs concentration of 1000 ng WHO₉₈-TEQ g⁻¹ fresh weight. Glutathione reductase (GR) enzyme activity increased monotonically at high level PCDD/Fs, but the activity of catalase (CAT) was only slightly affected at all treatment. Meanwhile, the exposure to PCDD/Fs resulted in the changes of hormones content. With the increase of exposure concentration of PCDD/Fs, the levels of indole-3-acetic acid (IAA) and abscisic acid (ABA) increased, whereas the concentration of jasmonates (JAs) decreased. The above results suggest that tobacco cells had the ability to cope with the oxidative stress induced by low concentration of PCDD/Fs through increasing the activities of antioxidant enzymes and alternating plant hormones levels. However, oxidative stress and toxicity would burst out when plant cells were exposed to the high levels of PCDD/Fs.     

Assays of PCB congeners and organochlorine insecticides with the transgenic Arabidopsis and tobacco plants carrying recombinant guinea pig AhR and GUS reporter genes

Certain congeners of polychlorinated biphenyls (PCBs) and organochlorine insecticides are ligands of aryl hydrocarbon receptors (AhRs) in animals. A recombinant guinea pig (g) AhR, XgDV, was constructed by fusing the ligand-binding domain of gAhR, the DNA-binding domain of LexA, and the transactivating domain of VP16. Then, the expression unit of β-glucuronidase (GUS) reporter gene regulated by XgDV was introduced into Arabidopsis and tobacco plants. When the transgenic Arabidopsis XgDV plants were cultured on Murashige–Skoog (MS) medium containing PCB congeners, the GUS activity in the plants increased toxic equivalent (TEQ)-dependently. The GUS activity in the transgenic Arabidopsis XgDV plants cultured on MS medium containing the organochlorine insecticide dieldrin was also induced. On the other hand, in the case of DDT, the GUS activity induced by 3-methylcholanthere in the plants decreased. The transgenic Arabidopsis XgDV plants detected 1000 ng g^?1 PCB126 in 1 g of soils. Thus the XgDV plants seemed to be useful for convenient assays of PCB congeners and organochlorine insecticides, without any extraction and purification steps.     

Seasonal variation of organochlorine contaminants in bonito (Sarda sarda L. 1758) and anchovy (Engraulis encrasicolus L. 1758) in Black Sea region, Turkey

The concentrations of indicator polychlorinated biphenyls (PCBs) and organochlorine insecticides were determined in bonito (Sardasarda L. 1758) and anchovy (Engraulisencrasicolus L. 1758) from the Black Sea, Turkey. Concentrations of total indicator PCBs ranged between <1-17.0 in bonito, and <1-17.5 ng/g fresh weight in anchovy, and total of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane and its metabolites’ (DDTs) concentrations ranged between 13.4-26.3, and 2.96-19.0 ng/g fresh weight in bonito and anchovy respectively. PCB 52, p,p′-DDE and endosulfan (α + β) were found dominant in both of the fish species. Except endosulfan, and some DDT metabolites, none of the studied organochlorine pesticides was detected in the fish samples. Concentrations of PCBs in anchovy were found higher than those in bonito, whereas DDT and endosulfan concentrations were found similar in both of the fish species. All of the fish samples had residue concentrations below the maximum residue limits (MRL) recommended by FAO/WHO Codex Alimentarius Commission.     

Incidence of thyroid disease following exposure to polybrominated biphenyls and polychlorinated biphenyls, Michigan, 1974-2006

Thyroid hormones, which influence body metabolism and development, could be affected by persistent organic pollutants. We sought to examine the relationship between polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) and thyroid disease. We employed incidence density sampling to perform a nested case control analysis of the Michigan Long-Term PBB Cohort. Cohort members (n = 3333) were exposed to PBBs through contaminated cattle feed in 1973-1974 and to PCBs through daily life. Those with detectable serum PBB and PCB concentrations at enrollment were categorized into tertiles of PBB and PCB exposure. Case-patients were cohort members answering “Yes” to “Has a healthcare provider ever told you that you had a thyroid problem?” during follow-up interviews; control-patients were cohort members answering “No”. We used odds ratios (OR) with 95% confidence intervals (CI) to compare odds of thyroid disease by PBB and PCB exposure and by various risk factors. Total cumulative thyroid disease incidence after 33 years was 13.9% among women and 2.6% among men. After adjusting for body mass index, we found no statistically significant differences in odds of any type of thyroid disease among women or men with elevated PBB or PCB exposure. Compared to control-patients, women with thyroid disease had increased odds of being overweight/obese (OR = 2.82, 95% CI: 1.94-4.11) and developing infertility (OR = 1.71, 95% CI: 1.08-2.69), diabetes (OR = 1.61, 95% CI: 1.04-2.51), or arthritis (OR = 1.71, 95% CI: 1.18-2.50) during follow-up. Additional research should explore potential associations between PBBs/PCBs and thyroid disease among children exposed in utero.     

Formation of toxic species and precursors of PCDD/F in thermal decomposition of alpha-cypermethrin

This article examines the thermal decomposition of alpha-cypermethrin, one of the most common pyrethroid pesticides. The objective was to identify its decomposition pathways and to gain an understanding into the formation of toxic species in the environment, including those that may behave in combustion systems, especially in fires in the environment, as precursors for PCDD/F (polychlorinated dibenzo-p-dioxins and dibenzofurans). The experiments were conducted under non-oxidative conditions using a tubular reactor housed in a three-zone heating furnace and operated with a dilute stream of alpha-cypermethrin in 99.999% nitrogen. The condensable products were identified and quantitated, after being collected in a cold solvent trap and in an activated charcoal cartridge. The study revealed the formation of pollutants including precursors of toxic PCDD/F such as diphenyl ether and phenol. It was also found that the decomposition of alpha-cypermethrin involved parallel pathways of an unusual vinylcyclopropane rearrangement-cum-aromatisation reaction transforming alpha-cypermethrin and a rupture of the C(O)OC(CN) linkage. The former is similar to that occurring in the decomposition of permethrin pesticide, whereas the latter constitutes a newly discovered channel for the formation of pollutants. Density functional theory (DFT) calculations allowed us to attribute the occurrence of the second pathway to the effect of the cyanide group in significantly weakening the OC bond.     

Prediction of the PCDD/F and dl-PCB 2005-WHO-TEQ content based on the contribution of six congeners: Toward a new screening approach for fish samples?

Current European Union regulation regarding polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in food and feed is based on Toxic Equivalent Quotient (TEQ) concept. For confirmatory purpose, the isotope-dilution method associated to a measurement by gas chromatography coupled with high resolution mass spectrometry is usually the method of choice for precisely measuring the 29 target congeners in three separated fractions. Time and cost related to these analyses are very significant. Various kinds of screening concepts can be considered. In the present study, we elaborated and validated a prediction model for the 2005 World Health Organization TEQ in fish, based on the measurement of 4 PCDD/F and 2 non-ortho dl-PCB congeners, potentially analyzable in a single extracted fraction by gas chromatography coupled with mass spectrometry. Large independent datasets have been used for model elaboration (n = 108) and validation (n = 363, n = 357 and n = 6).     

浅谈串联四极杆质谱（GC—QqQ-MS／MS）在土壤样品有机污染物分析中的应用

建立了ASE-GPC—GC-QqQ—MS／MS测定土壤中17种有机氯农药和19种多氯联苯以及MAE-SPE—GC-QqQ—MS／MS测定土壤中16种多环芳烃和18种邻苯二甲酸酯的方法。多环芳烃和邻苯二甲酸酯定量限在0．02～2．81μg／kg之间,有机氯农药和多氯联苯定量限在0．01～0．51μg/kg之间。样品加标浓度在5μg/kg时多环芳烃和邻苯二甲酸酯的平均回收率在66．6％～122．1％之间,相对标准偏差均小于20％;有机氯农药和多氯联苯平均回收率在79．6％～93．2％之间,相对标准偏差均小于15％。     

嗜吡啶红球菌多氯联苯降解基因的克隆与表达

建立了多氯联苯/联苯降解菌嗜吡啶红球菌 R04 的基因组文库.活性筛选得到 1 个18kb的阳性片断,内含 1个 921个核苷酸的新的开环酶2,3-二羟基联苯双加氧酶基因 bphC2,该基因能够在大肠杆菌中表达,其蛋白分子量约为34kDa.此外,在该基因上游39bp处还发现另外一个 2,3-二羟基联苯双加氧酶基因 bphC1 的部分序列.