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1.
Food Addit Contam Part B Surveill ; 11(2): 126-137, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29547065

RESUMO

This work reports data on the occurrence of nine mycotoxins and two food processing contaminants - acrylamide and furan - in a total of 100 beers produced in Latvia. Mycotoxins were detected by high-performance liquid chromatography (HPLC) coupled with time-of-flight mass spectrometry, acrylamide by HPLC coupled with quadrupole-Orbitrap mass spectrometry, and furan by headspace gas chromatography-mass spectrometry. The most frequently occurring mycotoxins were HT-2 and deoxynivalenol (DON), which were detected in 52% and 51% of the analysed samples. The highest content was observed for DON, reaching the maximum of 248 µg kg-1. Furan was ubiquitous, and 74% of the samples contained acrylamide. In terms of the estimated exposure, the biggest potential risk was identified for HT-2 representing more than 11% of tolerable weekly intake. The margin of exposure approach indicated the exposure to furan through beer as significant, this parameter being close to the critical limit.


Assuntos
Acrilamida/análise , Cerveja/análise , Carcinógenos Ambientais/análise , Contaminação de Alimentos , Furanos/análise , Micotoxinas/análise , Acrilamida/toxicidade , Consumo de Bebidas Alcoólicas/efeitos adversos , Métodos Analíticos de Preparação de Amostras , Cerveja/efeitos adversos , Cerveja/economia , Calibragem , Carcinógenos Ambientais/química , Carcinógenos Ambientais/toxicidade , Cromatografia Líquida de Alta Pressão , Inquéritos sobre Dietas , Manipulação de Alimentos , Inspeção de Alimentos/métodos , Furanos/química , Furanos/toxicidade , Humanos , Letônia , Limite de Detecção , Micotoxinas/toxicidade , Medição de Risco , Toxina T-2/análogos & derivados , Toxina T-2/análise , Toxina T-2/toxicidade , Tricotecenos/análise , Tricotecenos/toxicidade , Volatilização
2.
Food Chem Toxicol ; 84: 260-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26344759

RESUMO

The way in which mixture risk assessment (MRA) should be included in chemical risk assessment is a current topic of debate. We used data from 67 recent pesticide evaluations to build a case study using Hazard Index calculations to form risk estimates in a tiered MRA approach in line with a Framework proposed by WHO/IPCS. The case study is used to illustrate the approach and to add detail to the existing Framework, and includes many more chemicals than previous case studies. A low-tier MRA identified risk as being greater than acceptable, but refining risk estimates in higher tiers was not possible due to data requirements not being readily met. Our analysis identifies data requirements, which typically expand dramatically in higher tiers, as being the likely cause for an MRA to fail in many realistic cases. This forms a major obstacle to routine implementation of MRA and shows the need for systematic generation and collection of toxicological data. In low tiers, hazard quotient inspection identifies chemicals that contribute most to the HI value and thus require attention if further refinement is needed. Implementing MRA requires consensus on issues such as scope setting, criteria for performing refinement, and decision criteria for actions.


Assuntos
Modelos Biológicos , Resíduos de Praguicidas/toxicidade , Praguicidas/toxicidade , Toxicologia/métodos , Algoritmos , Animais , Carcinógenos Ambientais/química , Carcinógenos Ambientais/toxicidade , Inibidores da Colinesterase/química , Inibidores da Colinesterase/toxicidade , Bases de Dados de Compostos Químicos , Disruptores Endócrinos/química , Disruptores Endócrinos/toxicidade , Estudos de Viabilidade , Contaminação de Alimentos , Humanos , Irritantes/química , Irritantes/toxicidade , Estrutura Molecular , Mutagênicos/química , Mutagênicos/toxicidade , Resíduos de Praguicidas/química , Praguicidas/química , Medição de Risco , Toxicologia/normas , Reino Unido , Nações Unidas , Organização Mundial da Saúde
3.
Food Chem Toxicol ; 83: 174-82, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26115597

RESUMO

This study was conducted to prepare and characterize activated carbon (AC) and to evaluate its protective effect against deoxynivalenol (DON) toxicity in rats compared to Egyptian montmorillonite (EM). AC was prepared using a single-step chemical activation with phosphoric acid (H3PO4). The resulted AC has a high surface area and a high total pore volume. Male Sprague-Dawley rats were divided into 6 groups (n = 10) and treated for 3 weeks as follow: the control group, the groups fed AC or EM-supplemented diet (0.5% w/w), the group treated orally with DON (5 mg/kg b.w.) and the groups fed AC or EM-supplemented diet and treated with DON. Blood and liver samples were collected for different analyses. Treatment with DON increased liver function enzymes, lipid peroxidation, tumor necrosis factor α, DNA fragmentation, decreased hepatic glutathione content, up regulating mRNA Fas and TNF-α genes expression and increased micronucleated polychromatic erythrocytes and normochromatic erythrocytes in bone marrow. Co-treatment of DON plus AC or EM succeeded to normalize the levels of the biochemical parameters, reduced the cytotoxicity of bone marrow and ameliorated the hepatic genotoxicity. Moreover, AC was more effective than EM and has a high affinity to adsorb DON and to reduce its cytotoxicity and genotoxicity.


Assuntos
Carbono/uso terapêutico , Carcinógenos Ambientais/toxicidade , Quelantes/uso terapêutico , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Fígado/efeitos dos fármacos , Mutagênicos/toxicidade , Tricotecenos/antagonistas & inibidores , Animais , Bentonita/uso terapêutico , Carbono/química , Carbono/economia , Carcinógenos Ambientais/química , Quelantes/química , Quelantes/economia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Egito , Indústria de Processamento de Alimentos/economia , Indicadores e Reagentes/química , Resíduos Industriais/análise , Resíduos Industriais/economia , Fígado/metabolismo , Masculino , Mutagênicos/química , Phoeniceae/química , Ácidos Fosfóricos/química , Porosidade/efeitos dos fármacos , Ratos Sprague-Dawley , Sementes/química , Propriedades de Superfície/efeitos dos fármacos , Tricotecenos/toxicidade
4.
Food Chem Toxicol ; 83: 61-7, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26072099

RESUMO

This work studies on the quantitative analysis and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in edible vegetable oils in Shandong, China. The concentrations of 15 PAHs in 242 samples were determined by high performance liquid chromatography coupled with fluorescence detection. The results indicated that the mean concentration of 15 PAHs in oil samples was 54.37 µg kg(-1). Low molecular weight PAH compounds were the predominant contamination. Especially, the carcinogenic benzo(a)pyrene (BaP) was detected at a mean concentration of 1.28 µg kg(-1), which was lower than the limit of European Union and China. A preliminary evaluation of human health risk assessment for PAHs was accomplished using BaP toxic equivalency factors and the incremental lifetime cancer risk (ILCR). The ILCR values for children, adolescents, adults, and seniors were all larger than 1 × 10(-6), indicating a high potential carcinogenic risk on the dietary exposed populations.


Assuntos
Carcinógenos Ambientais/toxicidade , Gorduras Insaturadas na Dieta/efeitos adversos , Contaminação de Alimentos , Inspeção de Alimentos/métodos , Mutagênicos/toxicidade , Óleos de Plantas/efeitos adversos , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Benzo(a)pireno/análise , Benzo(a)pireno/química , Benzo(a)pireno/toxicidade , Carcinógenos Ambientais/análise , Carcinógenos Ambientais/química , China , Cromatografia Líquida de Alta Pressão , Gorduras Insaturadas na Dieta/análise , Gorduras Insaturadas na Dieta/economia , Gorduras Insaturadas na Dieta/normas , União Europeia , Guias como Assunto , Humanos , Limite de Detecção , Peso Molecular , Mutagênicos/análise , Mutagênicos/química , Óleo de Amendoim , Óleos de Plantas/química , Óleos de Plantas/economia , Óleos de Plantas/normas , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Reprodutibilidade dos Testes , Medição de Risco , Poluentes do Solo/análise , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Espectrometria de Fluorescência
5.
Environ Sci Pollut Res Int ; 22(17): 13412-26, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25940472

RESUMO

The size distribution of total and water-soluble elemental concentrations in six particle sizes <0.49, 0.49-0.97, 0.97-1.5, 1.5-3.0, 3.0-7.2, and 7.2-30 µm was investigated in Thessaloniki area, N. Greece, at two sites representing urban-traffic and urban-background character during the cold and warm period. The elements As, Cd, Cr, Cu, Pb, Ni, Zn, Ru, and Ir exhibited their highest mass portion in the fine particle mode (0.97-1.5 µm), whereas Al, Ba, Ca, Fe, and Mn occurred predominately in the coarse particle mode (3.0-7.2 µm). The water-soluble elemental fractions exhibited significant spatiotemporal variations and particle size dependence. Possible non-carcinogenic and carcinogenic risks associated with inhalation of particle-bound elements based on total and water-soluble concentrations were in acceptable levels. However, the cumulative risk for all potential particle-bound constituents has to be considered.


Assuntos
Carcinógenos Ambientais/análise , Material Particulado/análise , Carcinógenos , Carcinógenos Ambientais/química , Cidades , Grécia , Humanos , Exposição por Inalação , Metais Pesados/análise , Metais Pesados/química , Tamanho da Partícula , Material Particulado/química , Medição de Risco , Estações do Ano , Solubilidade , Solventes/química , População Urbana , Água/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-25393691

RESUMO

Arsenic is a metalloid that occurs in food and the environment in different chemical forms. Inorganic arsenic is classified as a class I carcinogen. The inorganic arsenic intake from food and drinking water varies depending on the geographic arsenic background. Non-dietary exposure to arsenic is likely to be of minor importance for the general population within the European Union. In Europe, arsenic in drinking water is on average low, but food products (e.g. rice and seaweed) are imported from all over the world including from regions with naturally high arsenic levels. Therefore, specific populations living in Europe could also have a high exposure to inorganic arsenic due to their consumption pattern. Current risk assessment is based on exposure via drinking water. For a good estimation of the risks of arsenic in food, it is important to investigate if the bioavailability of inorganic arsenic from food is different from drinking water. The present study further explores the issue of European dietary exposure to inorganic arsenic via rice and seaweed and its associated health risks. The bioavailability of inorganic arsenic was measured in in vitro digestion experiments. The data indicate that the bioavailability of inorganic arsenic is similar for rice and seaweed compared with drinking water. The calculated dietary intake for specific European Union populations varied between 0.44 and 4.51 µg kg⁻¹ bw day⁻¹. The margins of exposure between the inorganic intake levels and the BMDL0.5 values as derived by JECFA are low. Decreasing the intake of inorganic arsenic via Hijiki seaweed could be achieved by setting legal limits similar to those set for rice by the Codex Alimentarius Commission in July 2014.


Assuntos
Arsênio/toxicidade , Carcinógenos Ambientais/toxicidade , Dieta/efeitos adversos , Contaminação de Alimentos , Modelos Biológicos , Oryza/química , Alga Marinha/química , Adulto , Arsênio/análise , Arsênio/química , Disponibilidade Biológica , Carcinógenos Ambientais/análise , Carcinógenos Ambientais/química , Digestão , Água Potável/química , União Europeia , Política de Saúde , Humanos , Estrutura Molecular , Países Baixos , Medição de Risco , Sementes/química , Toxicocinética , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
7.
Artigo em Inglês | MEDLINE | ID: mdl-25396715

RESUMO

Palm kernel cake (PKC) is a useful source of protein and energy for livestock. Recently, it has been used as an ingredient in poultry feed. Mycotoxin contamination of PKC due to inappropriate handling during production and storage has increased public concern about economic losses and health risks for poultry and humans. This concern has accentuated the need for the evaluation of mycotoxins in PKC. Furthermore, a method for quantifying mycotoxins in PKC has so far not been established. The aims of this study were therefore (1) to develop a method for the simultaneous determination of mycotoxins in PKC and (2) to validate and verify the method. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using an electrospray ionisation interface (ESI) in both positive- and negative-ion modes was developed for the simultaneous determination of aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB1 and FB2), T-2 and HT-2 toxin in PKC. An optimum method using a 0.2 ml min⁻¹ flow rate, 0.2% formic acid in aqueous phase, 10% organic phase at the beginning and 90% organic phase at the end of the gradient was achieved. The extraction of mycotoxins was performed using a solvent mixture of acetonitrile-water-formic acid (79:20:1, v/v) without further clean-up. The mean recoveries of mycotoxins in spiked PKC samples ranged from 81% to 112%. Limits of detection (LODs) and limits of quantification (LOQs) for mycotoxin standards and PKC samples ranged from 0.02 to 17.5 µg kg⁻¹ and from 0.06 to 58.0 µg kg⁻¹, respectively. Finally, the newly developed method was successfully applied to PKC samples. The results illustrated the fact that the method is efficient and accurate for the simultaneous multi-mycotoxin determination in PKC, which can be ideal for routine analysis.


Assuntos
Ração Animal/análise , Arecaceae/química , Carcinógenos Ambientais/análise , Contaminação de Alimentos/prevenção & controle , Inspeção de Alimentos/métodos , Micotoxinas/análise , Sementes/química , Ração Animal/economia , Animais , Arecaceae/microbiologia , Calibragem , Carcinógenos Ambientais/química , Cromatografia Líquida de Alta Pressão , Indústria de Processamento de Alimentos/economia , Resíduos Industriais/análise , Resíduos Industriais/economia , Limite de Detecção , Malásia , Estrutura Molecular , Micotoxinas/química , Aves Domésticas , Reprodutibilidade dos Testes , Sementes/microbiologia , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
8.
Artigo em Inglês | MEDLINE | ID: mdl-25325777

RESUMO

Aflatoxicosis has repeatedly affected Kenyans, particularly in the eastern region, due to consumption of contaminated maize. However, save for the cases of acute toxicity, the levels of sub-lethal exposure have not been adequately assessed. It is believed that this type of exposure does exist even during the seasons when acute toxicity does not occur. This study, therefore, was designed to assess the exposure of households to aflatoxins through consumption of maize and maize products. Twenty samples each of maize kernels, muthokoi and maize meal were randomly sampled from households in Kibwezi District of Makueni County in Eastern Kenya and analysed for aflatoxin contamination. The samples were quantitatively analysed for aflatoxin contamination using HPLC. The uncertainty and variability in dietary exposure was quantitatively modelled in Ms Excel using Monte Carlo simulation in @Risk software. Aflatoxins were found in 45% of maize kernels at between 18 and 480 µg kg⁻¹, 20% of muthokoi at between 12 and 123 µg kg⁻¹, and 35% of maize meal at between 6 and 30 µg kg⁻¹. The mean dietary exposure to aflatoxin in maize kernels was 292 ± 1567 ng kg⁻¹ body weight day⁻¹, while the mean dietary exposure to aflatoxin in maize meal and muthokoi were 59 ± 62 and 27 ± 154 ng kg⁻¹ body weight day⁻¹ respectively. The results showed that the amount and frequency of consumption of the three foods is the more important contributing factor than the mean aflatoxin concentration levels, to the risk of dietary exposure to aflatoxins.


Assuntos
Aflatoxinas/toxicidade , Carcinógenos Ambientais/toxicidade , Dieta/efeitos adversos , Contaminação de Alimentos , Manipulação de Alimentos , Sementes/química , Zea mays/química , Adulto , Aflatoxinas/análise , Aflatoxinas/antagonistas & inibidores , Sulfato de Amônio/química , Carcinógenos Ambientais/análise , Carcinógenos Ambientais/química , Criança , Estudos Transversais , Países em Desenvolvimento , Dieta/etnologia , Monitoramento Ambiental , Características da Família , Contaminação de Alimentos/prevenção & controle , Conservantes de Alimentos/química , Humanos , Quênia , Método de Monte Carlo , Oxidantes/química , Medição de Risco , Sementes/microbiologia , Zea mays/microbiologia
9.
J Agric Food Chem ; 62(32): 8051-9, 2014 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-25025712

RESUMO

A new solid-phase extraction (SPE) format was demonstrated, based on eggshell membrane (ESM) templating of the mixed hemimicelle/admicelle of linear alkylbenzenesulfonates (LAS) as an adsorbent for the enrichment of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in environmental aqueous samples. The LAS mixed hemimicelle/admicelle formation and SPE of the target PAHs were conducted simultaneously by adding the organic target and LAS through a column filled with 500 mg of ESM. The effect of various factors, including LAS concentration, solution pH, ionic strength, and humic acid concentration on the recoveries of PAHs were investigated and optimized. The results showed that LAS concentration and solution pH had obvious effect on extraction of PAHs, and the recoveries of PAHs compounds decreased in the presence of salt and humic acid. Under the optimized analytical conditions, the present method could respond down to 0.1-8.6 ng/L PAHs with a linear calibration ranging from 0.02 to 10 µg/L, showing a good PAHs enrichment ability with high sensitivity. The developed method was used satisfactorily for the detection of PAHs in environmental water samples. The mixed hemimicelle/admicelle adsorbent exhibited high extraction efficiency to PAHs and good selectivity with respect to natural organic matter and was advantageous over commercial C18 adsorbent, for example, high extraction yield, high breakthrough volume, and easy regeneration.


Assuntos
Carcinógenos Ambientais/isolamento & purificação , Casca de Ovo/química , Monitoramento Ambiental/métodos , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Ácidos Alcanossulfônicos/química , Animais , Carcinógenos Ambientais/análise , Carcinógenos Ambientais/química , Galinhas , China , Casca de Ovo/ultraestrutura , Monitoramento Ambiental/economia , Indústria de Processamento de Alimentos/economia , Substâncias Húmicas/análise , Concentração de Íons de Hidrogênio , Resíduos Industriais/análise , Resíduos Industriais/economia , Limite de Detecção , Membranas/química , Membranas/ultraestrutura , Micelas , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Reprodutibilidade dos Testes , Extração em Fase Sólida , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
10.
Clin Ter ; 164(5): e429-35, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24217845

RESUMO

Worldwide tobacco smoking kills nearly 6 million people each year, including more than 600,000 non-smokers who die from smoke exposure. Environmental tobacco smoke (ETS, also called secondhand smoke, involuntary smoke, or passive smoke) is the combination of sidestream smoke, the smoke given off by a burning tobacco product and mainstream smoke, the smoke exhaled by smokers. People may be exposed to ETS in homes, cars, workplaces, and public places, such as bars, restaurants, and recreational settings. In addition, there is another type of smoke which until now has not been recognized: the so-called thirdhand smoke, that comes from the reaction of mainstream smoke and environmental nitrous acid (HNO2) making carcinogenic tobacco-specific nitrosamines (TSNAs). The effects of ETS on human health are well-known, passive smoking is harmful to those who breathe the toxins and it is a serious problem for public health. The smoking ban in Italy had reduced ETS pollution, as in the United States and in other countries all over the world. However, the implementation of comprehensive legislation on smoking policy will necessitate other tobacco control measures for its successful fulfillment: increased media awareness, telephone smoking cessation helplines and smoking cessation support services could be an opportunity to ensure awareness, comprehension and support to those who want to quit smoking. The effectiveness of legislative efforts will also depend on successful enforcement of smoking bans and compliance with the legislation. This review summarizes the evidences about the effect of ETS and provides an overview of smoke-free laws and policies.


Assuntos
Política de Saúde/legislação & jurisprudência , Poluição por Fumaça de Tabaco/legislação & jurisprudência , Poluentes Atmosféricos/química , Carcinógenos Ambientais/química , Carcinógenos Ambientais/toxicidade , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/prevenção & controle , Sinergismo Farmacológico , Exposição Ambiental , Saúde Global , Política de Saúde/tendências , Humanos , Itália/epidemiologia , Neoplasias/etiologia , Neoplasias/mortalidade , Neoplasias/prevenção & controle , Nitrosaminas/química , Nitrosaminas/toxicidade , Ácido Nitroso/química , Doenças Respiratórias/etiologia , Doenças Respiratórias/mortalidade , Doenças Respiratórias/prevenção & controle , Poluição por Fumaça de Tabaco/efeitos adversos , Poluição por Fumaça de Tabaco/prevenção & controle
11.
Artigo em Inglês | MEDLINE | ID: mdl-21660819

RESUMO

Chloro-s-triazines have been a mainstay of preemergent pesticides for a number of decades and have generally been regarded as having low human toxicity. Atrazine, the major pesticide in this class, has been extensively studied. In a number of experimental studies, exposure to high doses of atrazine resulted in increased weight loss not attributable to decreased food intake. Chronic studies of atrazine and simazine and their common metabolites show an elevated incidence of mammary tumors only in female Sprague Dawley (SD) rats. On the basis of the clear tumor increase in female SD rats, atrazine was proposed to be classified as a likely human carcinogen by US Environmental Protection Agency (EPA) in 1999. With Fischer rats, all strains of mice, and dogs, there was no evidence of increased incidence of atrazine-associated tumors of any type. Evidence related to the pivotal role of hormonal control of the estrus cycle in SD rats appears to indicate that the mechanism for mammary tumor induction is specific to this strain of rats and thus is not relevant to humans. In humans the menstrual cycle is controlled by estrogen released by the ovary rather than depending on the LH surge, as estrus is in SD rats. However, the relevance of the tumors to humans continues to be debated based on endocrine effects of triazines. No strong evidence exists for atrazine mutagenicity, while there is evidence of clastogenicity at elevated concentrations. Atrazine does not appear to interact strongly with estrogen receptors α or ß but may interact with putative estrogen receptor GPR30 (G-protein-coupled receptor). A large number of epidemiologic studies conducted on manufacturing workers, pesticide applicators, and farming families do not indicate that triazines are carcinogenic in these populations. A rat-specific hormonal mechanism for mammary tumors has now been accepted by US EPA, International Agency for Research on Cancer, and the European Union. Chlorotriazines do influence endocrine responses, but their potential impact on humans appears to be primarily on reproduction and development and is not related to carcinogenesis.


Assuntos
Atrazina/toxicidade , Carcinógenos Ambientais/toxicidade , Praguicidas/toxicidade , Reprodução/efeitos dos fármacos , Triazinas/toxicidade , Animais , Atrazina/química , Atrazina/farmacocinética , Testes de Carcinogenicidade , Carcinógenos Ambientais/química , Carcinógenos Ambientais/farmacocinética , Cães , Sistema Endócrino/efeitos dos fármacos , Exposição Ambiental/análise , Estro/efeitos dos fármacos , Feminino , Humanos , Masculino , Neoplasias Mamárias Animais/induzido quimicamente , Camundongos , Testes de Mutagenicidade , Praguicidas/química , Praguicidas/farmacocinética , Ratos , Ratos Endogâmicos F344 , Ratos Long-Evans , Medição de Risco , Triazinas/química , Triazinas/farmacocinética
12.
Chemosphere ; 69(5): 697-704, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17604817

RESUMO

As a carcinogen, hexamethyldisilazane (HMDS) is extensively adopted in life science microscopy, materials science and nanotechnology. However, no appropriate technology has been devised for treating HMDS in gas streams. This investigation evaluated the feasibility and effectiveness of the UV (185+254nm) and UV (254nm)/O(3) processes for degradation of gaseous HMDS. Tests were performed in two batch reactors with initial HMDS concentrations of 32-41mgm(-3) under various initial ozone dosages (O(3) (mg)/HMDS (mg)=1-5), atmospheres (N(2), O(2), and air), temperatures (28, 46, 65 and 80 degrees C), relative humilities (20%, 50%, 65%, 99%) and volumetric UV power inputs (0.87, 1.74, 4.07 and 8.16Wl(-1)) to assess their effects on the HMDS degradation rate. Results indicate that for all conditions, the decomposition rates for the UV (185+254nm) irradiation exceeded those for the UV (254nm)/O(3) process. UV (185+254nm) decompositions of HMDS displayed an apparent first-order kinetics. A process with irradiation of UV (185+254nm) to HMDS in air saturated with water at temperatures of 46-80 degrees C favors the HMDS degradation. With the condition as above and a P/V of around 8Wl(-1), k was approximately 0.20s(-1) and a reaction time of just 12s was required to degrade over 90% of the initial HMDS. The main mechanisms for the HMDS in wet air streams irradiated with UV (185+254nm) were found to be caused by OH free-radical oxidation produced from photolysis of water or O((1)D) produced from photolysis of oxygen. The economic evaluation factors of UV (185+254nm) and UV (254nm)/O(3) processes at different UV power inputs were also estimated.


Assuntos
Poluentes Atmosféricos/química , Poluição do Ar/prevenção & controle , Carcinógenos Ambientais/química , Compostos de Organossilício/química , Ozônio/química , Raios Ultravioleta , Poluentes Atmosféricos/efeitos da radiação , Carcinógenos Ambientais/efeitos da radiação , Gases , Compostos de Organossilício/efeitos da radiação , Fotoquímica
13.
Environ Int ; 32(1): 12-21, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16154195

RESUMO

The lifetime cancer risk and the hazard index of trihalomethanes (THMs) through oral ingestion, dermal absorption, and inhalation exposure from tap water of 15 districts in Istanbul are estimated. The most dominant THM compounds are chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) in Istanbul tap water. The results indicate that within three different pathways, Istanbul residents had a higher cancer risk through oral ingestion than through the other two pathways. The lifetime cancer risks of oral ingestion for total THMs was highest in Esenyurt district, while the lowest lifetime cancer risk for total THMs was in Basaksehir district. The lifetime cancer risks of chloroform, BDCM, and DBCM from tap water of all 15 districts were higher than 10(-6), the negligible risk level defined by the USEPA. Among the 15 districts, people living in Esenyurt have the highest risk of cancer due to the THM exposure through the multi-pathways, mainly because of the exposure to BDCM and DBCM. The total cancer risk analysis concluded that each year approximately 5 of the 8 million Istanbul residents could get cancer from the daily intake of tap water.


Assuntos
Ingestão de Líquidos , Exposição Ambiental , Trialometanos/administração & dosagem , Trialometanos/toxicidade , Abastecimento de Água/análise , Idoso , Carcinógenos Ambientais/química , Carcinógenos Ambientais/metabolismo , Carcinógenos Ambientais/toxicidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/induzido quimicamente , Neoplasias/epidemiologia , Medição de Risco , Fatores de Risco , Pele/efeitos dos fármacos , Trialometanos/análise , Trialometanos/química , Turquia/epidemiologia , Poluentes Químicos da Água/administração & dosagem , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
14.
Toxicol Appl Pharmacol ; 203(3): 192-200, 2005 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-15737674

RESUMO

Of the known toxins produced by cyanobacteria, microcystins and nodularins are the most significant threat to human and animal health. Knock-out studies have confirmed that microcystins are produced nonribosomally by a multienzyme complex consisting of peptide synthetases, polyketide synthases, and tailoring enzymes. Gene clusters for microcystin biosynthesis have been identified and sequenced in the distantly related cyanobacterial genera Microcystis, Planktothrix, and Anabaena. Homologous genes have been detected in a nodularin-producing Nodularia strain. Subsequently, microcystin biosynthesis (mcy) genes have been used to establish molecular techniques for the detection of toxigenic cyanobacteria in laboratory and field studies. mcy genes of unknown origin can be assigned to the producing species. Techniques are currently being developed for the quantification of mcy genes in field populations. These initial genetic investigations pave the way for a molecular monitoring of microcystin- and nodularin-producing cyanobacteria and for studying the dynamics of toxic cyanobacteria in lakes. Furthermore, microcystin-deficient mutants have significantly increased our knowledge about the impact of the toxins on Microcystis-Daphnia interactions. The experience gained on microcystin biosynthesis genes will be valuable for a risk assessment of microcystin in the environment and for future water management and lake-restoration strategies.


Assuntos
Toxinas Bacterianas/genética , Carcinógenos Ambientais , Peptídeos Cíclicos/genética , Animais , Toxinas Bacterianas/química , Carcinógenos Ambientais/química , Humanos , Microcistinas , Peptídeos Cíclicos/química , Medição de Risco
15.
Chem Res Toxicol ; 14(1): 11-5, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11170503

RESUMO

Fumonisin B(1), a potent mycotoxin found in grain, has been resistant to degradation and detoxification by a variety of methods, including milling, fermentation, ammoniation, and ozonation. The primary amine of this compound contributes significantly to its toxicity; therefore, the major aim of this research was to remove this moiety via diazotization. In this study, fumonisin B(1) was deaminated in aqueous solution under conditions of acidic pH and low temperature (pH 1.0 and 5 degrees C) with the addition of NaNO(2). The concentration of fumonisin B(1) in the solution was analyzed by HPLC using o-phthaldialdehyde to derivatize the primary amine. Progress of the reaction was monitored as a loss of the derivatized peak as observed by HPLC with fluorescence detection. TLC analysis showed the disappearance of fumonisin B(1) following diazotization. Further, TLC displayed at least four reaction products that were not primary amines. Matrix-assisted laser desorption/ionization mass spectrometry coupled with time-of-flight analysis of the diazotization products also showed a diminished amount of authentic fumonisin B(1) and allowed identification of a product formed by the replacement of the primary amine with a hydroxyl group. The adult Hydra attenuata bioassay indicated a marked decrease in the toxicity of the products in comparison to parent fumonisin B(1). Optimization of this reaction could result in a rapid and practical method for the reclamation of fumonisin B(1)-contaminated feeds.


Assuntos
Ácidos Carboxílicos/química , Ácidos Carboxílicos/toxicidade , Fumonisinas , Micotoxinas/química , Micotoxinas/toxicidade , Animais , Ácidos Carboxílicos/farmacocinética , Carcinógenos Ambientais/química , Carcinógenos Ambientais/farmacocinética , Carcinógenos Ambientais/toxicidade , Cromatografia Líquida de Alta Pressão , Desaminação , Hydra/efeitos dos fármacos , Inativação Metabólica , Micotoxinas/farmacocinética , Nitrito de Sódio/química , Espectrometria de Fluorescência , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
16.
Arch Environ Contam Toxicol ; 35(3): 527-31, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9732487

RESUMO

In order to assess the lifetime risk of skin cancer for recreational users from dermal exposure to polycyclic aromatic hydrocarbons (PAHs), sediment samples were collected from beach sites along the St. Marys River near Sault Ste. Marie, Ontario, and in Hamilton Harbor and Toronto Harbor, Ontario, and analyzed for PAHs. Dermal exposure and lifetime skin cancer risk were estimated as follows: Concentrations of 11 PAHs with sufficient or limited evidence of carcinogenicity or mutagenicity were converted to benzo(a)pyrene (BaP) equivalents using toxic equivalency factors (TEFs). Lifetime dermal exposure values were derived based on the BaP equivalents in the silt + clay fraction taken as representative of suspended sediment particulates to which recreational users would be exposed. The lifetime health risk of skin cancer associated with such exposures was above the negligible risk level of 1.0 x 10(-6) at offshore Rytac, Lake George Channel, and Bell Point beaches in the St. Marys River; at Pier 4 Park in Hamilton Harbor; and at Humber Bay, Sunnyside Beach, Cherry Beach, and Water Rats Sailing Club in Toronto Harbor. Risk was negligible inshore at the Rytac and Bell Point beaches and at Squirrel Island and Ojibway Trailer Park along St. Marys River, at Lax Beach in Hamilton Harbor; and at Centre Island in Toronto Harbor. Strategies to reduce risk were developed with these communities; a key recommendation was to take a bath or shower within 24 h after a swim because virtually all the PAHs on the skin would be removed.


Assuntos
Carcinógenos Ambientais/efeitos adversos , Sedimentos Geológicos/análise , Hidrocarbonetos Policíclicos Aromáticos/efeitos adversos , Neoplasias Cutâneas/induzido quimicamente , Poluentes Químicos da Água/efeitos adversos , Animais , Carcinógenos Ambientais/análise , Carcinógenos Ambientais/química , Humanos , Ontário , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Ratos , Medição de Risco , Poluentes Químicos da Água/análise
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