Organochlorine pesticides residues and PCBs in benthic organisms of the inner shelf of the São Sebastião Channel, São Paulo, Brazil

Trinta e sete amostras de bentos da área interna do Canal de São Sebastião, Brasil, foram coletadas entre Abril de 1994 e Agosto de 1998 e analisadas quanto aos níveis de resíduos de 17 pesticidas organoclorados os congêneres dos PCBs. Os níveis de resíduos de organoclorados e PCBs foram baixos( ng/g) e encontrados com maior freqüência nas amostras de crustáceos. DDE foi o resíduo de pesticida encontrado com mais freqüência apresentado um máximo de 9,7 ng/g seguido dos isômeros de HCHs com um máximo de 17,1 ng/g. No caso dos PCBs os congêneres mais pesados foram os predominantes: CB 138, 153, 170, 180 e 183. O valor máximo de PCBs totais foi de 17,4 ug/g numa amostra de crustáceo. Níveis maiores de PCBs estão associados aos hábitos alimentares e introduções pontuais de esgotos e água de drenagem urbana. Apesar dos níveis observados estarem abaixo dos recomendados para consumo humano pela EPA e da FDA( U.S.A) ,eles demonstram que mesmo em área marinhas costeiras sem agricultura intensiva ou atividades industriais de porte , estes compostos orgânicos persistentes sintéticos ( POPS) estão presentes em níveis mensuráveis.Thirty seven benthic samples of the inner shelf area of São Sebastião, Brazil, were collected between April 1994 and August 1998 and analysed for seventeen chlorinated pesticide residues and PCBs congeners. Pesticide residues and PCBs congeners levels were low (ng/g) and predominantly found in the crustacean samples. DDE was the most frequently residue with a maximum of 9,7 ng/g followed by HCHs with maximum of 17,1ng/g. As for the PCBs, the heavier congeners predominate: CB 138,153,170, 180 and 183. Maximum total PCBs was 17,4 ug/g in a crab sample. Higher levels of PCBs are related to feeding habits and local inputs of raw sewage or land runoff. Although EPA and FDA (U.S.A) below the guidelines for human consumption propose these levels, they do show that even in marine areas without intense agricultural or industrial activities these compounds are present at detectable levels

Survey of petroleum aromatic hydrocarbons in the São Sebastião Channel, SP, Brazil, November 1985 to August 1986

A survey of the petroleum aromatic hydrocarbons levels on the surface waters of the São Sebastião Channel, São Paulo, Brazil is presented. The survey was done in order to assess the influence of the biggest maritime oil terminal of Brazil on the petroleum hydrocarbons levels of the area. Fourty four samples taken from 1 m depth were analysed by fluorescence spectroscopy. The highest level, 45.29 µg.1-1, was found on the side of an anchored tanker and the lowest detectable level was 0.19 µg.1-1.Foi realizado um levantamento dos níveis de hidrocarbonetos do petróleo em águas superficiais do Canal de São Sebastião, São Paulo, Brasil. Esse levantamento foi feito para avaliar a influência de hidrocarbonetos do petróleo do maior terminal de óleo do país. Foram coletadas 44 amostras a 1 m de profundidade, extraídas em n-hexano e analisadas por espectrofluorescência. O ponto de maior concentração, 45,29 µg.1-1, foi coletado ao lado de um navio petroleiro ancorado na região, e o menor valor detectado foi de 0.19 µg.1-1 proveniente da parte sul do Canal

Determinação de ΣDDT e PCBs na água do mar através de pré-concentração em resinas poliméricas

A pre-concenvration method for extracting organochlorines from seawater was employed to analyse ΣDDTs and PCBs. The sampling device and the conditions for optimal adsortion performance are described. Recovery tests with spiked solutions were made before applying the method on real samples. Working up of the samples prior to gas chromatographic analysis, precautions and advantages of the procedure are also discussed. The application of the method for seawater, containing very low levels of organochlorines, is shown by data from equatorial surface waters. The average level for ΣDDT and PCBs was 0.21 ng/l and 0.37 ng/l. The overall precision of the method is about ± 15% with a lower limit of detection of 0.1 ng/l-1 for PCBs and 0.05 ng/l-1 for ZDDT

The fate of an oil spill in São Sebastião channel: a case study

A ruptura de um oleoduto em maio de 1994 introduziu 2.700 tons de óleo cru no Canal de São Sebastião, contaminando algumas áreas. Na ocasião um monitoramento de hidrocarbonetos em sedimentos estava sendo realizado na região, utilizando o método de cromatografia em fase gasosa/ detecção por ionização de chama. Os dados obtidos nesse monitoramento foram comparados aos resultados das amostras coletadas logo após o acidente, com o objetivo de verificar a extensão da contaminação por óleo e os lugares mais atingidos. Os dados prévios mostraram duas fontes de introdução de hidrocarbonetos: biogênica, com predomínio de plantas superiores, e antrópica, causada por atividades náuticas e esgotos. Os dados posteriores mostraram que a estação de coleta mais próxima ao oleoduto foi a mais atingida. Na sequencia, as duas estações localizadas na entrada norte do canal apresentaram as maiores concentrações de n-alcanos, sugerindo que as correntes NE, impulsionadas pelo vento, transportaram o óleo no sentido norte do canal. Sete meses depois uma destas estações, aquela situada em local de alta energia, mostrou sinais de recuperação, o que, contudo, não foi observado na outra, considerada de ambiente deposicional. Em conclusão, pode-se afirmar que análises de hidrocarbonetos são ferramentas poderosas para avaliar o destino de um óleo e que a parte norte do Canal de São Sebastião tem maior probabilidade de ser afetada na ocasião de um derrame de óleo.An oil pipeline ruptured in May 1994 and 2 700 tons of crude oil leaked into the São Sebastião Channel, affecting several neighboring areas. A program for the monitoring of hydrocarbons in sediments, using the gas chromatography / flame ionization detector methodology, was being undertaken in the area at the time. The data obtained were compared to those of samples collected after the accident to determine the fate of the oil spilled and ascertain its contribution to the environment. The earlier results showed that hydrocarbons were introduced from two different sources: biogenic, mainly from terrestrial plants, and anthropogenic, as oil, in sewage and from shipping. The later data indicated that the site closest to the pipeline rupture had been the most affected. Following that, two stations located at the north entrance of the channel presented the highest n-alkane concentrations, suggesting that the northeasterly wind-driven currents had carried the oil northward. Seven months later, one of these stations, a high-energy site, showed some signs of recovery, but this process was not observed at the other, which seemed to be a low-energy site. In conclusion, the data showed that the aliphatic hydrocarbon analyses were powerful tools for the assessment of the fate of the oil spill and that the northern part of the São Sebastião Channel is more subject to the effects of oil spills

Four-year survey of dissolved/dispersed petroleum hydrocarbons on surface waters of Admiralty Bay, King George Island, Antarctica

Seawater from 8 stations in Admiralty Bay was systematically sampled during the summer of 1994, 1995, 1996 and 1997 and analyzed by spectrofluorimetry to measure dissolved/dispersed petroleum hydrocarbons (DDPHs). The purpose of this study was to detect some temporal and spatial changes in terms of oil contamination of the region. The results indicate low levels of oil pollution with relatively high concentrations near the research stations located in the study area. During the summers of 1995 and 1996 the average concentrations for individual stations were low and below of 0.50 ¼g.L-1. Summers of 1994 and 1997 had relatively higher average concentrations (up to 1.57 ¼g.L-1), mainly in front of Arctowski and Ferraz Research Stations.Amostras de água na Baía do Almirantado, Península Antártica, foram sistematicamente coletadas em 8 estações durante os verões de 1994 a 1997 onde foram analisados hidrocarbonetos do petróleo dispersos e dissolvidos por espectrofluorescência. O objetivo foi avaliar variações temporais e espaciais em termos de contaminação por óleo na região. Os resultados em geral indicam baixos níveis de poluição embora tenham sido verificadas algumas concentrações relativamente maiores nas proximidades das estações de pesquisa fixadas na região de estudo. Durante os anos de 1995 e 1996 a média das concentrações foram baixas e menores que 0,50 ¼g.L-1 para os pontos individuais. Os verões de 1994 e 1997 tiveram concentrações médias mais elevadas (até 1,57 ¼g.L-1), e os maiores valores foram nas proximidades das estações brasileira e polonesa

The Fate of an oil Spill In São Sebastião Channal: A case study

An oil pipeline ruptured in May 1994 and 2 700 tons of crude oil leaked into the São Sebastião Channel, affecting several neighboring areas. A program for the monitoring of hydrocarbons in sediments, using the gas chromatography / flame ionization detector methodology, was being undertaken in the area at the time. The data obtained were compared to those of samples collected after the accident to determine the fate of the oil spilled and ascertain its contribution to the environment. The earlier results showed that hydrocarbons were introduced from two different sources: biogenic, mainly from terrestrial plants, and anthropogenic, as oil, in sewage and from shipping. The later data indicated that the site closest to the pipeline rupture had been the most affected. Following that, two stations located at the north entrance of the channel presented the highest n-alkane concentrations, suggesting that the northeasterly wind-driven currents had carried the oil northward. Seven months later, one of these stations, a high-energy site, showed some signs of recovery, but this process was not observed at the other, which seemed to be a low-energy site. In conclusion, the data showed that the aliphatic hydrocarbon analyses were powerful tools for the assessment of the fate of the oil spill and that the northern part of the São Sebastião Channel is more subject to the effects of oil spills

Quantification of Sterol and Triterpenol Biomarkers in Sediments of the Cananéia-Iguape Estuarine-Lagoonal System (Brazil) by UHPLC-MS/MS

Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananéia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananéia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve

Precursor phase with full phonon softening above the charge-density-wave phase transition in 2H2H-TaSe2_2

Research on charge-density-wave (CDW) ordered transition-metal dichalcogenides continues to unravel new states of quantum matter correlated to the intertwined lattice and electronic degrees of freedom. Here, we report an inelastic x-ray scattering investigation of the lattice dynamics of the canonical CDW compound $2H$-TaSe$_2$ complemented by angle-resolved photoemission spectroscopy. Our results rule out the central-peak scenario for the CDW transition in $2H$-TaSe$_2$ and provide evidence for a novel precursor phase above the CDW transition temperature $T_{CDW}$. The phase at temperatures between $T^{*}\,(= 128.7\,,\rm{K})$ and $T_{CDW}\,(= 121.3\,\rm{K})$ is characterized by a fully softened phonon mode and medium-range ordered ($\xi_{corr} = 100\,\rm{\mathring{A}}- 200\,\rm{\mathring{A}})$ static CDW domains. Only $T_{CDW}$ is detectable in our photoemission experiments. Thus, $2H$-TaSe$_2$ exhibits structural before electronic static order and emphasizes the important lattice contribution to CDW transitions

Gas chromatography coupled to high resolution time-of-flight mass spectrometry as a high-throughput tool for characterizing geochemical biomarkers in sediments

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe performance of gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-HRTofMS) for characterizing geochemical biomarkers from sediment samples was evaluated. Two approaches to obtain the geochemical biomarkers were tested:2018FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2012/21395-0The authors would like to thank FAPESP (scholarship 2012/21395-0) for sponsoring this stud

Precursor region with full phonon softening above the charge-density-wave phase transition in 2H-TaSe2

Research on charge-density-wave (CDW) ordered transition-metal dichalcogenides continues to unravel new states of quantum matter correlated to the intertwined lattice and electronic degrees of freedom. Here, we report an inelastic x-ray scattering investigation of the lattice dynamics of the canonical CDW compound 2H-TaSe2 complemented by angle-resolved photoemission spectroscopy and density functional perturbation theory. Our results rule out the formation of a central-peak without full phonon softening for the CDW transition in 2H-TaSe2 and provide evidence for a novel precursor region above the CDW transition temperature TCDW, which is characterized by an overdamped phonon mode and not detectable in our photoemission experiments. Thus, 2H-TaSe2 exhibits structural before electronic static order and emphasizes the important lattice contribution to CDW transitions. Our ab-initio calculations explain the interplay of electron-phonon coupling and Fermi surface topology triggering the CDW phase transition and predict that the CDW soft phonon mode promotes emergent superconductivity near the pressure-driven CDW quantum critical point