Angiotensin II type 1 receptor is involved in hypertension and vascular alterations caused by environmental toxicant hexachlorobenzene.

Environmental hexachlorobenzene (HCB) increases blood pressure (BP) in female rats, causing alterations in arterial structure and function. Here we study the role of Angiotensin II receptor type 1 (AT1) in HCB-induced hypertension through the use of AT1 antagonist losartan. HCB-treated male rats showed a 22.7% increase in BP which was prevented by losartan. Losartan blocked HCB-induced changes in arterial morphology (decreased aorta cell number and increased wall thickness). Losartan also prevented HCB-induced alterations in artery relaxation by acetylcholine and nitroprusside but not the reduction in the maximum contraction by phenylephrine. Losartan rescued arterial molecular alterations caused by HCB (i.e. an increase in TGF-ß1 and AT1 expression and a decrease in eNOS expression and nitrite levels) and reduced hydrogen sulfide plasma concentration. In conclusion: in this work we demonstrate that AT1 activity is involved in HCB effects on the vascular system leading to hypertension.

Enhanced HCB removal using bacteria from mangrove as post-treatment after electrochemical oxidation using a laser-prepared Ti/RuO2-IrO2-TiO2 anode.

The environmental persistence of hexachlorobenzene (HCB) is a challenge that promotes studies for efficient treatment alternatives to minimize its environmental impact. Here, we evaluated the HCB removal by electrochemical, biological, and combined approaches. The electrochemical treatment of 4 µM HCB solutions was performed using a synthesized Ti/RuO2-IrO2-TiO2 anode, while the biological treatment using mangrove-isolated bacteria was at 24, 48, and 72 h. The HCB degradability was assessed by analyzing chemical oxygen demand (COD), microbial growth capacity in media supplemented with HCB as the only carbon source, gas chromatography, and ecotoxicity assay after treatments. The synthesized anode showed a high voltammetric charge and catalytic activity, favoring the HCB biodegradability. All bacterial isolates exhibited the ability to metabolize HCB, especially Bacillus sp. and Micrococcus luteus. The HCB degradation efficiency of the combined electrochemical-biological treatment was evidenced by a high COD removal percentage, the non-HCB detection by gas chromatography, and a decrease in ecotoxicity tested with lettuce seeds. The combination of electrochemical pretreatment with microorganism degradation was efficient to remove HCB, thereby opening up prospects for in situ studies of areas contaminated by this recalcitrant compound.

Latitudinal distribution of OCPs in the open ocean atmosphere between the Argentinian coast and Antarctic Peninsula.

Long-range atmospheric transport is one of the most important ways in which persistent organic pollutants can be transported from their source to remote and pristine regions. Here, we report the results of the first Argentinian measurements of organochlorine pesticides in the Antarctic region. During a 9665-km track onboard OV ARA Puerto Deseado, within the framework of Argentinian Antarctic Expeditions, air samples were taken using high-volume samplers and analyzed using GC-µECD. HCB, HCHs, and endosulfans were the major organic pollutants found, and a north-south gradient in their concentrations was evident by comparing data from the Argentinian offshore zone to the South Scotia Sea.

Synthesis and characterization of (6-{[2-(pyridin-2-yl)hydrazinylidene]methyl}pyridin-2-yl)methanol: a supramolecular and topological study.

Hydrazones exhibit a versatile chemistry and are of interest for their potential use as functional molecular systems capable of undergoing reversible changes of configuration, i.e. E/Z isomerization. The title compound, C12H12N4O, has an E configuration with respect to the hydrazone C=N bond. The crystal packing is formed by N-H...N and O-H...N hydrogen bonds that give a two-dimensional layer structure and C-H...C interactions associated with layer stacking to produce the three-dimensional supramolecular structure. These intermolecular interactions were analyzed and quantified by the Hirshfeld surface method and the two-dimensional supramolecular arrangement was topologically simplified as a hcb network.

Persistent organic pollutants and polycyclic aromatic hydrocarbons in mosses after fire at the Brazilian Antarctic Station.

A fire at the Brazilian Antarctic Station on February 25th, 2012 led to the burning of material that produced organic pollutants. To evaluate the impact in the surrounding area, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs) were analyzed in moss samples collected in the vicinities of the station before and after the incident and compared to findings from previous studies in the same region. PCBs were on the same magnitude as that reported in previous studies, which could be associated to the global dispersion of these compounds and may not be related to the local fire. In contrast, concentrations of HCB and PAHs were higher than those reported in previous studies. No PBDEs were found above the method detection limit. Organic contaminant concentrations in mosses decreased a few months after the fire, which is an important characteristic when considering the use of mosses for monitoring recent exposure.

Estabelecimento de metodologias de extração de hexaclorobenzeno (hcb) de sedimento e água de estuário e do mar

ABSTRACT Hexachlorobenzene (HCB) has been widely used as a fungicide and is also a by-product of several industrial processes, such as solvent manufacturing. Its lipophilic and hydrophobic nature, besides its low rate of chemical and biological degradation, can lead to its bio-accumulation and bio-magnification throughout the food net. Therefore, its detection and quantification in organisms and environment are extremely important, and this creates the need for efficient methodologies allowing for its detection and quantification for environmental contamination studies, in a low-cost way. The present study compared different methods of HCB extraction from estuary and sea sediments and waters, assessing the advantages of each method. The recovery tests were performed with samples of estuary and sea sediments, and waters previously treated with HCB in mixture with 14C-HCB as a radiotracer, and the radiocarbon in the extracts was quantified by liquid scintillation counting (LSC). The recovery of 14C-HCB from waters was compared by hexane extraction in C18 cartridges and liquid-liquid extraction, also using hexane. The recovery of 14C-HCB from the sediments was tested with the mixture hexane:acetone and microwave energy. The solid phase (C18) extraction was the best method for water extraction, accounting for 88.3% and 83.4% of recovery, respectively, from estuary and seawater. The microwave extraction recovered 99.5% and 99.9% of14C-HCB, respectively from estuary and sea sediments. The cost/benefit ratio indicates the C-18 solid phase extraction for waters and the microwave extraction for sediments as the best recovery methods, which allow for good detection of HCB in pollution studies.

RESUMO O hexaclorobenzeno (HCB) foi amplamente utilizado como fungicida e é também subproduto de vários processos industriais, como na fabricação de solventes. Suas características químicas o tornam pouco disponível à degradação química e biológica, levando a bio-acumulação e biomagnificação ao longo da cadeia alimentar. Assim, sua detecção e quantificação em organismos e no ambiente são importantes e, para isto, metodologias eficientes devem possibilitar o rastreamento e a quantificação de contaminação ambiental da maneira mais econômica. Este trabalho comparou diferentes métodos de extração de HCB de sedimentos e águas de estuário e de mar, avaliando as vantagens de cada método. Os testes de recuperação utilizaram amostras de sedimentos e águas de estuário e mar tratadas com HCB em mistura com 14C-HCB como radiotraçador e quantificação do radiocarbono por espectrometria de cintilação em líquido (ECL). A recuperação de 14C-HCB das águas foi comparada por extração das amostras com hexano em coluna C18 e extração líquido-líquido também com hexano como solvente. Nos sedimentos testouse extração com mistura de hexano:acetona e energia de microondas. A extração por fase sólida (C18) foi o melhor método de extração de água, com 88,3% e 83,4% de recuperação, respectivamente de água de estuário e de mar. A extração de sedimento por microondas recuperou 99,5% e 99,9% de radiocarbono, respectivamente de sedimentos de estuário e de mar. A análise custo/benefício indica a extração por coluna C18 para águas e a extração por microondas para sedimentos como os melhores métodos de recuperação e que possibilitarão boa detecção de HCB em estudos de poluição.

Relação entre a freqüência de consumo de carne e pescado e os níveis de hexaclorobenzeno, lindano, aldrin e 4,4' - diclorodifenil - 1,1' dicloroetileno, em tecido adiposo de glândulas mamárias de mulheres espanholas

The levels of organochlorine pesticide residues FONT FACE=Symbol>¾ /FONT> hexaclorobenzene (HCB), lindane (gamma-HCH), aldrin and 4,4'dichloro diphenil 1,1'dichloroethylene (p,p'-DDE) - present in mammary adipose tissue samples from women living in Cordoba (Spain) were evaluated. The compound found at the highest concentration was p,p´-DDE (1.869(mug/g of adipose tissue), which was present in 100% of the analyzed samples. The average levels of HCB, gamma-HCH and aldrin were 0.236, 0.003 and 0.006mug/g of adipose tissue, respectively. The tissue levels of organochlorine residues were correlated with the weekly intake of meat and fish by donors. Only the tissue levels of p-p´-DDE were significantly (p FONT FACE=Symbol>£ /FONT>0.05) affected by the frequency of meat intake. Donors with a meat intake higher than four times a week presented an average level of 2.833mug/g of adipose tissue.

Níveis de resíduos dos pesticidas organoclorados, hexaclorobenzeno (HCB), lindano gama-HCH), aldrin e 4,4'-diclorodifenil-1,1'dicloroetileno (p,p'-DDE) foram determinados em tecido adiposo mamário de mulheres residentes em Córdoba, Espanha. A maior concentração média foi detectada para o p,p'-DDE (1,869 mig/g de tecido adiposo), que estava presente em 100% das amostras. As concentrações médias de HCB, gama-HCH e aldrin encontrados foram 0,236, 0,003 e 0,006mig/g de tecido adiposo, respectivamente. Os níveis dos resíduos detectados nas amostras foram relacionados ao consumo semanal de carne e pescado pelas doadoras. O único composto cujos níveis variaram significativamente (p FONT FACE=Symbol>£ /FONT>0,05) em função da freqüência de consumo de carne foi o p,p'-DDE, tendo apresentado concentração média de 2,833 mig/g de tecido adiposo quando as doadoras relataram uma freqüência de consumo de carne superior a quatro vezes por semana.

Relação entre a freqüência de consumo de carne e pescado e os níveis de hexaclorobenzeno, lindano, aldrin e 4,4' - diclorodifenil - 1,1' dicloroetileno, em tecido adiposo de glândulas mamárias de mulheres espanholas

The levels of organochlorine pesticide residues FONT FACE=Symbol>¾ /FONT> hexaclorobenzene (HCB), lindane (gamma-HCH), aldrin and 4,4'dichloro diphenil 1,1'dichloroethylene (p,p'-DDE) - present in mammary adipose tissue samples from women living in Cordoba (Spain) were evaluated. The compound found at the highest concentration was p,p´-DDE (1.869(mug/g of adipose tissue), which was present in 100% of the analyzed samples. The average levels of HCB, gamma-HCH and aldrin were 0.236, 0.003 and 0.006mug/g of adipose tissue, respectively. The tissue levels of organochlorine residues were correlated with the weekly intake of meat and fish by donors. Only the tissue levels of p-p´-DDE were significantly (p FONT FACE=Symbol>£ /FONT>0.05) affected by the frequency of meat intake. Donors with a meat intake higher than four times a week presented an average level of 2.833mug/g of adipose tissue.

Níveis de resíduos dos pesticidas organoclorados, hexaclorobenzeno (HCB), lindano gama-HCH), aldrin e 4,4'-diclorodifenil-1,1'dicloroetileno (p,p'-DDE) foram determinados em tecido adiposo mamário de mulheres residentes em Córdoba, Espanha. A maior concentração média foi detectada para o p,p'-DDE (1,869 mig/g de tecido adiposo), que estava presente em 100% das amostras. As concentrações médias de HCB, gama-HCH e aldrin encontrados foram 0,236, 0,003 e 0,006mig/g de tecido adiposo, respectivamente. Os níveis dos resíduos detectados nas amostras foram relacionados ao consumo semanal de carne e pescado pelas doadoras. O único composto cujos níveis variaram significativamente (p FONT FACE=Symbol>£ /FONT>0,05) em função da freqüência de consumo de carne foi o p,p'-DDE, tendo apresentado concentração média de 2,833 mig/g de tecido adiposo quando as doadoras relataram uma freqüência de consumo de carne superior a quatro vezes por semana.