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1.
Rev Environ Contam Toxicol ; 251: 25-108, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31011832

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are a class of hazardous organic contaminants that are widely distributed in nature, and many of them are potentially toxic to humans and other living organisms. Biodegradation is the major route of detoxification and removal of PAHs from the environment. Aerobic biodegradation of PAHs has been the subject of extensive research; however, reports on anaerobic biodegradation of PAHs are so far limited. Microbial degradation of PAHs under anaerobic conditions is difficult because of the slow growth rate of anaerobes and low energy yield in the metabolic processes. Despite the limitations, some anaerobic bacteria degrade PAHs under nitrate-reducing, sulfate-reducing, iron-reducing, and methanogenic conditions. Anaerobic biodegradation, though relatively slow, is a significant process of natural attenuation of PAHs from the impacted anoxic environments such as sediments, subsurface soils, and aquifers. This review is intended to provide comprehensive details on microbial degradation of PAHs under various reducing conditions, to describe the degradation mechanisms, and to identify the areas that should receive due attention in further investigations.


Assuntos
Bactérias Anaeróbias/metabolismo , Biodegradação Ambiental , Poluentes Ambientais/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Nitratos
2.
Rev Environ Contam Toxicol ; 252: 97-129, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31346776

RESUMO

Human milk may sometimes contain chemical contaminants, which could have adverse effects on neonates or nursing infants. Lead (Pb) is of considerable interest due to its toxicity and occurrence. Furthermore, it has been suggested that human milk is a significant potential source of lead exposure to nursing infants. A systematic literature search in PubMed, Science Direct, and Google Scholar databases was performed to identify relevant studies, published in English until 2017, that investigated and explored common factors affecting the level of lead in human milk among lactating women around the world. Forty-nine papers were rated and explored the effect of one or several factors on the level of lead in human milk from 28 countries and carried out over a wide time frame from 1983 to 2017 and through Europe, Asia, America, and Africa, reviewing more than 5,000 subjects. Place of residence, maternal age, stage of lactation, smoking habits, maternal dietary intakes, and parity were the mostly assessed factors among the studies and considered as the main factors affecting Pb levels in BM. Other factors were not studied well enough and considered minor because few surveys evaluated their impacts. However, the literature findings are very controversial.


Assuntos
Poluentes Ambientais/metabolismo , Lactação , Chumbo/metabolismo , Leite Humano/metabolismo , Feminino , Humanos , Recém-Nascido , Gravidez
3.
Sci Total Environ ; 690: 1178-1189, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31470481

RESUMO

Microbial arsenic transformation is important in As biogeochemical cycles in the environment. In this study, a new As-resistant bacterial strain Leclercia adecarboxylata As3-1 was isolated and its associated mechanisms in As resistance and detoxification were evaluated based on genome sequencing and gene annotations. After subjecting strain As3-1 to medium containing arsenate (AsV), AsV reduction occurred and an AsV-enhanced bacterial growth was observed. Strain As3-1 lacked arsenite (AsIII) oxidation ability and displayed lower AsIII resistance than AsV, probably due to its higher AsIII accumulation. Polymerase chain reaction and phylogenetic analysis showed that strain As3-1 harbored a typical AsV reductase gene (arsC) on the plasmids. Genome sequencing and gene annotations identified four operons phoUpstBACS, arsHRBC, arsCRDABC and ttrRSBCA, with 8 additional genes outside the operons that might have involved in As resistance and detoxification in strain As3-1. These included 5 arsC genes explaining why strain As3-1 tolerated high AsV concentrations. Besides ArsC, TtrB, TtrC and TtrA proteins could also be involved in AsV reduction and consequent energy acquisition for bacterial growth. Our data provided a new example of diverse As-regulating systems and AsV-enhanced growth without ArrA in bacteria. The information helps to understand the role of As in selecting microbial systems that can transform and utilize As.


Assuntos
Arsênico/metabolismo , Enterobacteriaceae/fisiologia , Poluentes Ambientais/metabolismo , Adaptação Fisiológica , Proteínas de Bactérias/genética , Enterobacteriaceae/genética , Genômica
4.
Sci Total Environ ; 692: 1106-1115, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539942

RESUMO

The aim of this study was to investigate levels of polybrominated diphenyl ethers (PBDEs) in breast milk samples from healthy primiparous mothers who had lived in Kampala capital city (urban area) and Nakaseke district (a rural area) for the last five years. Fifty samples were collected between March and June 2018 and were extracted by dispersive solid-phase extraction (SPE). Clean-up was performed on an SPE column and analysis was done using gas chromatography-mass spectrometry. Total (∑) PBDEs (BDE 28, 47, 49, 66, 77, 99, 100,138,153, 154, 183 and 209) ranged from 0.59 to 8.11 ng/g lipid weight (lw). The levels of PBDEs in samples from Kampala capital city were significantly higher than those from Nakaseke (p < 0.01, Mann-Whitney U test). The most dominant congeners were BDE-209 and -47 (contributed 37.1% and 20.2%, respectively to ∑PBDEs), suggesting recent exposure of mothers to deca-and penta-BDE formulations. Fish and egg consumption, plastics/e-waste recycling and paint fumes were associated with higher levels of BDE-47, -153 and -99, respectively, implying that diet and occupation were possible sources of the pollutants. Estimated dietary intakes (ng kg-1 body weight day-1) for BDE-47, -99 and -153 were below the US EPA reference doses for neurodevelopmental toxicity, suggesting minimal health risks to nursing infants who feed on the milk. Generally, the risk quotients for BDE-47, -99 and -153 were <1 in majority (96%) samples, indicating that the breast milk of mothers in Uganda was fit for human consumption.


Assuntos
Poluentes Ambientais/metabolismo , Éteres Difenil Halogenados/metabolismo , Exposição Materna , Leite Humano/metabolismo , Resíduo Eletrônico , Feminino , Humanos , Lactente , Bifenil Polibromatos , Uganda
5.
Sci Total Environ ; 685: 1152-1159, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31390705

RESUMO

Increasing evidence supports that maternal exposure to vanadium (V) is associated with adverse birth outcomes including preterm birth and low birth weight. However, the effect of V exposure on intrauterine fetal growth and the underlying biological mechanism are still unclear. The present study includes 227 mother-infant pairs from the Shanghai Maternal-Child Pairs Cohort to assess the gender-specific effect of intrauterine V exposure on fetal growth and related cytokines. Maternal blood samples were collected to measure V concentration and biomarkers of growth. We used multiple linear regression to evaluate the gender-specific effect of prenatal V exposure on birth parameter and growth-related cytokines. Mixed-effect models were applied to assess the non-linear association between gestational V exposure and intrauterine fetal growth. Covariates adjusted in the regression models as potential confounders including maternal age, pre-pregnancy body mass index, gestational weeks, parity, socio-demographic status, etc. Results showed that prenatal V exposure was negatively associated with birth weight (ß = -64.73) in female newborns and body length (ß = -0.10) in male. During the fetal period, maternal V exposure was associated with decreased biparietal diameter (ß = -0.91), head circumference (ß = -2.96), femur length (ß = -0.72) and humerus length (ß = -0.64) in male. Trimester-specific analyses showed that serum V concentration in the second trimester was associated with significant reductions in intrauterine growth parameters. Besides, prenatal V exposure could down-regulate the expression of growth hormone (GH) in both maternal blood (ß = -0.23) and umbilical cord blood (ß = -1.66) in male fetuses, and the expression of brain derived neurotrophic factor (BDNF) in cord blood in females (ß = -0.52). Our results suggest that prenatal V exposure has a gender-specific effect on fetal growth and the second trimester may be a sensitive window. The disruption of grow-related cytokines may potentially be the biological mechanism of these effects.


Assuntos
Citocinas/metabolismo , Poluentes Ambientais/metabolismo , Exposição Materna/estatística & dados numéricos , Vanádio/metabolismo , Peso ao Nascer , Índice de Massa Corporal , China , Estudos de Coortes , Feminino , Desenvolvimento Fetal , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Gravidez , Nascimento Prematuro
6.
Toxicol Lett ; 315: 64-76, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31419470

RESUMO

To test the hypothesis that 3-7 ring polycyclic aromatic hydrocarbons (PAHs) are responsible for the prenatal developmental toxicity (PDT) as observed with some petroleum substances (PS), the present study evaluates the PDT potency of DMSO-extracts of 7 heavy fuel oils (HFO), varying in their PAH content, and 1 highly refined base oil (HRBO), containing no aromatics, in the embryonic stem cell test (EST). All DMSO-extracts of HFO inhibit ES-D3 cell differentiation in a concentration-dependent manner and their potency is proportional to the amount of 3-7 ring PAHs they contain. All DMSO-extracts of HFOs also show aryl hydrocarbon receptor (AhR)-mediated activities, as tested in the AhR-CALUX assay. Contrarily, the HRBO-extract tested negative in both assays. Co-exposure of ES-D3 cells with selected DMSO-extracts of PS and the AhR-antagonist trimethoxyflavone, successfully counteracted the PS-induced inhibition of ES-D3 cell differentiation, confirming the role of the AhR in mediating the observed PDT of PS extracts in the EST. A good correlation exists when comparing the in-vitro with the in-vivo PDT potencies of the PS under study. Altogether, our findings corroborate the hypothesis that PS-induced PDT is caused by 3-7 ring PAHs present in these substances and that the observed PDT is partially AhR-mediated.


Assuntos
Células-Tronco Embrionárias/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Petróleo/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Receptores de Hidrocarboneto Arílico/metabolismo , Bioensaio , Poluentes Ambientais/metabolismo , Feminino , Humanos , Petróleo/metabolismo , Gravidez
7.
Bull Environ Contam Toxicol ; 103(3): 468-475, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273422

RESUMO

The aim of the present research was to determine the trace metal accumulations in Trigonella foenum-graecum irrigated with three different water regimes (ground water, canal water and sugar mill water). Also, transfer factors, pollution load indices, and health risk indices were assessed to evaluate metal transport and accumulation through the food chain. The analysis was conducted by Atomic Absorption Spectrophotometer (Shimadzu model AA-6300) to evaluate the concentration of metals in water, soil and vegetables. Trace metal concentrations in water samples ranged from 0.84 to 1.67, 0.42 to 0.72, 0.45 to 0.85, 2.51 to 9.99, 1.21 to 1.92, 1.82 to 9.98 and 0.64 to 0.91 mg/kg for Cd, Cr, Cu, Fe, Ni, Zn and Mn, respectively. The mean metal concentrations in soil samples were determined as 0.25, 0.86, 0.96, 3.37, 0.4, 0.44 and 2.31 mg/kg for Cd, Cr, Cu, Fe, Ni, Zn and Mn, respectively. Trace metal accumulations in T. foenum-graecum samples gathered from where soil samples were taken are as follows: The contents of Cd, Cr, Cu, Fe, Ni, Zn and Mn ranged from 0.48 to 1.06, 0.11 to 0.35, 0.15 to 0.29, 1.43 to 8.39, 0.39 to 0.54, 2.1 to 3.05 and 0.42 to 0.47 mg/kg, respectively. Statistical analyses showed that the treatments have non-significant effect (p > 0.05) on concentrations of metals in T. foenum-graecum samples collected from three sites for Ni, Cr, Cu, Zn and Mn and significant effect on Fe and Cd.


Assuntos
Poluentes Ambientais/metabolismo , Contaminação de Alimentos/análise , Oligoelementos/metabolismo , Trigonella/metabolismo , Verduras/metabolismo , Águas Residuárias/química , Monitoramento Ambiental , Poluentes Ambientais/análise , Humanos , Medição de Risco , Solo/química , Oligoelementos/análise , Trigonella/química , Verduras/química , Águas Residuárias/toxicidade
8.
Sci Total Environ ; 691: 631-643, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31325863

RESUMO

Contaminants in the marine environment are widespread, but ship-based sampling routines are much narrower. We evaluated the utility of seabirds, highly-mobile marine predators, as broad samplers of contaminants throughout three tropical ocean regions. Our aim was to fill a knowledge gap in the distributions of, and processes that contribute to, tropical marine contaminants; and explore how species-specific foraging ecologies could inform or bias our understanding of contaminant distributions. Mercury and persistent organic pollutant (POPs) concentrations were measured in adults of five seabird species from four colonies in the central Pacific (Laysan and Tern Islands, Hawaii; Palmyra Atoll) and the eastern Caribbean (Barbuda). Blood-based total mercury (THg) and 89 POPs were measured in two seabird families: surface-foraging frigatebirds (Fregata spp.) and plunge-diving boobies (Sula spp.). Overall, largescale contaminant differences between colonies were more informative of contaminant distributions than inter-specific foraging ecology. Model selection results indicated that proximity to human populations was the best predictor of THg and POPs. Regional differences in contaminants were distinct: Barbudan Magnificent Frigatebirds had more compounds (n=52/89 POP detected) and higher concentrations (geometric mean THg=0.97µgg-1; mean ΣPOP53=26.6ngmL-1) than the remote colonies (34-42/89 POP detected; range of THg geometric means=0.33-0.93µgg-1; range of mean ΣPOP53:7.3-17.0ngmL-1) and had the most recently-synthesized POPs. Moderate differences in foraging ecologies were somewhat informative of inter-specific differences in contaminant types and concentrations between nearshore and offshore foragers. Across species, contaminant concentrations were higher in frigatebirds (THg=0.87µgg-1; ΣPOP53=17.5ngmL-1) compared to boobies (THg=0.48µgg-1; ΣPOP53=9.8). Ocean currents and contaminants' physiochemical properties provided additional insight into the scales of spatial and temporal contaminant exposure. Seabirds are excellent, broad samplers with which we can understand contaminant distributions in the marine environment. This is especially important for tropical remote regions that are under-sampled.


Assuntos
Aves/metabolismo , Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Poluição Ambiental/estatística & dados numéricos , Animais , Poluentes Ambientais/análise , Mercúrio/análise
9.
Sci Total Environ ; 691: 1051-1058, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31326797

RESUMO

Anticoagulant rodenticides (ARs) are known to cause extensive secondary exposure in top predators in Europe and North America, but there remains a paucity of data in Asia. In this study, we collected 221 liver samples from 21 raptor species in Taiwan between 2010 and 2018. Most birds were recovered from rescue organizations, but some free-ranging individuals were obtained from bird-strike prevention measures at airports. ARs were detected in 10 species and more than half of the total samples. Common rodent-eating Black-winged Kites (Elanus caeruleus) had the highest prevalence (89.2%) and highest average sum concentration (0.211 ±â€¯0.219 mg/kg), which was similar between free-ranging birds at airports and injured birds from rescue organizations. Scavenging Black Kites (Milvus migrans) and snake-eating Crested Serpent-eagles (Spilornis cheela) had the second highest prevalence or sum concentration, respectively. Seven different AR compounds were detected, of which brodifacoum was the most common and had the highest average concentration, followed by flocoumafen and bromadiolone. The frequency of occurrence in the three most numerous species (Black-winged Kite, Crested Goshawk [Accipiter trivirgatus], and Collared Scops-owl [Otus lettia]) was significantly higher in autumn than summer, which is consistent with the timing of the Taiwanese government's supply of free ARs to farmers. Regional differences in the detection of individual compounds also tended to reflect differences in human population density and use patterns (in agriculture or urban-dominated environments). Clinical poisoning was confirmed in Black Kites with sum concentrations as low as 0.026 mg/kg; however, further study of interspecific differences in AR sensitivity and potential population effects are needed. In addition, continued monitoring remains important given the Taiwanese government has modified their farmland rodent control policy to gradually reduce free AR supplies since 2015.


Assuntos
Anticoagulantes/metabolismo , Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Aves Predatórias/metabolismo , Rodenticidas/metabolismo , 4-Hidroxicumarinas/metabolismo , Animais , Controle de Roedores , Rodenticidas/análise , Taiwan
10.
Environ Pollut ; 253: 872-881, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349196

RESUMO

Plant-endophyte synergism has been demonstrated to play a key role in the phytoremediation of contaminated water and soil. Phytoalexins, a type of chemical component in the plant apoplast, can be produced by plants in response to stimulation by endophytes. Phytoalexins may have distinct effects on the nutritional and metabolic functions of endophytes; however, direct evidence is not available to prove the effect of phytoalexins on the hydrophobic organic contaminants (HOC)-degradation activity of endophytes. In this paper, three different types of phytoalexins, coumarin, resveratrol and rutin, were selected to study their effect on the removal of polycyclic aromatic hydrocarbons (PAHs) by an endophytic bacterium Methylobacterium extorquens C1. The effects of the three phytoalexins on bacterial sorption and intracellular enzymatic activities were tested to further analyze the mechanism by which the phytoalexins affect the PAH degradation performance of M. extorquens C1. The results showed that the removal rate of PAHs by M. extorquens C1 increased in the presence of low levels of the three phytoalexins. The most effective concentrations of coumarin, resveratrol and rutin were 0.20, 0.15, and 0.25 mg/L, respectively, and the removal rate of PAHs was increased by approximately 18.3-35.0%. At the optimal concentrations, the three phytoalexins significantly promoted the sorption of PAHs by M. extorquens C1, and also enhanced the activities of catechol dioxygenases and dehydrogenase of M. extorquens C1. The positive effect of phytoalexins on both bacterial sorption and intracellular enzymatic activities promotes the overall removal of PAHs from endophytes. These results may deepen our understanding of plant-microbe cooperative mechanisms in the degradation of organic pollutants and provide a new approach for chemically enhanced bioremediation in the future.


Assuntos
Endófitos/metabolismo , Lolium/microbiologia , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Poluentes do Solo/metabolismo , Bactérias/metabolismo , Biodegradação Ambiental , Endófitos/isolamento & purificação , Poluentes Ambientais/metabolismo , Lolium/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/análise , Sesquiterpenos , Solo/química , Microbiologia do Solo , Poluentes do Solo/química
11.
Environ Pollut ; 253: 199-206, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31310870

RESUMO

There is a growing conservation concern about the possible consequences of environmental contamination in the health of bat communities. Most studies on the effects of contaminants in bats have been focused on organic contaminants, and the consequences of bat exposure to metals and metalloids remain largely unknown. The aim of this study was to evaluate the suitability of external biological matrices (fur and wing membrane) for the assessment of exposure and bioaccumulation of metals in bats. The concentration of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead, selenium and zinc was measured in internal organs (liver, heart, brain), internal (bone) and external tissues (wing membrane, fur) collected from bat carcasses of four species (Hypsugo savii, Nyctalus leisleri, Pipistrellus pipistrellus, Pipistrellus pygmaeus) obtained in windfarm mortality searches. With the exception of zinc (P = 0.223), the results showed significant differences between the concentrations of metals in the analyzed tissues for all metals (P < 0.05). Significant differences were also found between organs/tissues (P < 0.001), metals (P < 0.001) and a significant interaction between organs/tissues and metals was found (P < 0.001). Despite these results, the patterns in terms of metal accumulation were similar for all samples. Depending on the metal, the organ/tissue that showed the highest concentrations varied, but fur and wing had the highest concentrations for most metals. The variability obtained in terms of metal concentrations in different tissues highlights the need to define standardized methods capable of being applied in monitoring bat populations worldwide. The results indicate that wing membrane and fur, biological matrices that may be collected from living bats, yield reliable results and may be useful for studies on bats ecotoxicology, coupled to a standardized protocol for large-scale investigation of metal accumulation.


Assuntos
Quirópteros/metabolismo , Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Cabelo/metabolismo , Metaloides/metabolismo , Metais/metabolismo , Asas de Animais/metabolismo , Animais , Arsênico , Cádmio , Cromo , Cobre , Manganês , Metais/análise , Níquel , Selênio , Zinco
12.
Environ Pollut ; 253: 646-654, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31330356

RESUMO

Although plants are often exposed to atmospheric nanoparticles (NPs), the mechanism of NP deposition and their effects on physiology and metabolism, and particularly in combination with other stressors, are not yet understood. Exploring interactions between stressors is particularly important for understanding plant responses in urban environments where elevated temperatures can be associated with air pollution. Accordingly, 3-year-old spruce seedlings were exposed for 2 weeks to aerial cadmium oxide (CdO) NPs of environmentally relevant size (8-62 nm) and concentration (2 × 105 cm-3). While half the seedlings were initially acclimated to high temperature (35 °C) and vapour pressure deficit (VPD; 2.81 kPa), the second half of the plants were left under non-stressed conditions (20 °C, 0.58 kPa). Atomic absorption spectrometry was used to determine Cd content in needles, while gas and liquid chromatography was used to determine changes in primary and secondary metabolites. Photosynthesis-related processes were explored with gas-exchange and chlorophyll fluorescence systems. Our work supports the hypothesis that atmospheric CdO NPs penetrate into leaves but high temperature and VPD reduce such penetration due to stomatal closure. The hypothesis that atmospheric CdO NPs influences physiological and metabolic processes in plants was also confirmed. This impact strengthens with increasing time of exposure. Finally, we found evidence that plants acclimated to stress conditions have different sensitivity to CdO NPs compared to plants not so acclimated. These findings have important consequences for understanding impacts of global warming on plants and indicates that although the effects of elevated temperatures can be deleterious, this may limit other forms of plant stress associated with air pollution.


Assuntos
Poluentes Atmosféricos/toxicidade , Compostos de Cádmio/toxicidade , Nanopartículas/toxicidade , Óxidos/toxicidade , Picea/efeitos dos fármacos , Temperatura Ambiente , Abies , Aclimatação/fisiologia , Poluentes Ambientais/metabolismo , Aquecimento Global , Temperatura Alta , Fotossíntese/fisiologia , Picea/fisiologia , Pinus , Folhas de Planta/efeitos dos fármacos , Plântula/efeitos dos fármacos
13.
Chemosphere ; 233: 890-895, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340416

RESUMO

The reduction of halocarbons by NADH models and NADH under ambient conditions is reported as a new type of reactivity pointing towards a hitherto unknown disruptive pathway for NADH/NADPH-dependent processes. The reaction was studied with the omnipresent pesticide DDT, the inhalation anesthetic halothane, and several simple halocarbons. The halide-hydride exchange represents a biochemical equivalent for the reduction of halocarbons by traditional synthetic reagents like silanes (R3Si-H) and stannanes (R3Sn-H). High precision thermochemical calculations (CBS-QB3) reveal the carbon-hydrogen bond dissociation energy of NADH (70.8 kcal·mol-1) to be lower than that of stannane (SnH4: 78.1 kcal·mol-1), approaching that of the elusive plumbane (PbH4: 68.9 kcal·mol-1). The ready synthetic accessibility of NADH models, their low carbon-hydrogen bond dissociation energy, and their dehalogenation activity in the presence of air and moisture recommend these compounds as substitutes for the air-sensitive or toxic metal hydrides currently employed in synthesis.


Assuntos
DDT/metabolismo , Poluentes Ambientais/metabolismo , Recuperação e Remediação Ambiental/métodos , Halotano/metabolismo , Hidrocarbonetos Halogenados/análise , Hidrocarbonetos Halogenados/metabolismo , NAD/metabolismo , Carbono/química , Hidrogênio/química , Ligações de Hidrogênio , Indicadores e Reagentes , Silanos/química , Compostos de Estanho/química
14.
Sci Total Environ ; 690: 388-399, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299572

RESUMO

In this study we reconstruct the long-term exposure of Czech mothers to polychlorinated biphenyls (PCBs) and determine the causes of high contamination of breast milk by indicator PCBs (iPCBs). A data set containing information from more than 1000 primiparous women from the Czech Republic was used, including iPCB concentrations in breast milk, individual physiology and living characteristics. The time series of PCB intakes for the whole period from the beginning of PCB production in 1958 until 2011 were reconstructed. We estimated the individual lifetime exposure of mothers for all iPCBs, i.e. congeners 28, 52, 101, 118, 138, 153 and 180, using a physiologically based pharmacokinetic (PBPK) model. Various model scenarios were investigated to determine the influence of physiology, age at delivery, past dietary exposure, and food composition on concentrations in breast milk for all iPCBs. The highest contributions to the presence of iPCBs in breast milk were observed for food composition. The main factor determining the concentration of higher-chlorinated PCBs (138, 153 and 180) was past exposure. The most important parameter for identification of children's postnatal exposure through breast milk was the time-span from the maximum of the exposure peak to the birth of the child. The current concentrations of iPCBs in breast milk in the Czech population are still high because the maximum of the exposure peak occurred more than 10 years later than in other European countries and was very broad, e.g. covered more than 10 years.


Assuntos
Poluentes Ambientais/metabolismo , Exposição Materna/estatística & dados numéricos , Bifenilos Policlorados/metabolismo , Adulto , República Tcheca , Exposição Dietética/estatística & dados numéricos , Feminino , Humanos , Leite Humano
15.
Environ Pollut ; 253: 29-38, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31302400

RESUMO

Over 80,000 endocrine-disrupting chemicals (EDCs) are considered emerging contaminants (ECs), which are of great concern due to their effects on human health. Quantitative structure-activity relationship (QSAR) models are a promising alternative to in vitro methods to predict the toxicological effects of chemicals on human health. In this study, we assessed a deep-learning based QSAR (DL-QSAR) model to predict the qualitative and the quantitative effects of EDCs on the human endocrine system, and especially sex-hormone binding globulin (SHBG) and estrogen receptor (ER). Statistical analyses of the qualitative responses indicated that the accuracies of all three DL-QSAR methods were above 90%, and greater than the other statistical and machine learning models, indicating excellent classification performance. The quantitative analyses, as assessed using deep-neural-network-based QSAR (DNN-QSAR), resulted in a coefficient of determination (R2) of 0.80 and predictive square correlation coefficient (Q2) of 0.86, which implied satisfactory goodness of fit and predictive ability. Thus, DNN was able to transform sparse molecular descriptors into higher dimensional spaces, and was superior for assessment qualitative responses. Moreover, DNN-QSAR demonstrated excellent performance in the discipline of computational chemistry by handling multicollinearity and overfitting problems.


Assuntos
Aprendizado Profundo , Ecotoxicologia , Disruptores Endócrinos/toxicidade , Poluentes Ambientais/toxicidade , Relação Quantitativa Estrutura-Atividade , Biologia Computacional , Disruptores Endócrinos/metabolismo , Poluentes Ambientais/metabolismo , Humanos , Redes Neurais (Computação) , Receptores Estrogênicos/metabolismo , Globulina de Ligação a Hormônio Sexual
16.
J Environ Radioact ; 207: 7-14, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31151051

RESUMO

Preliminary values of whole organism concentration ratio (CRwo-soil) were derived for terrestrial vertebrates of an Australian tropical savanna environment. Wildlife groups included bird, bat, ground-dwelling mammal and reptile. Sample data for some of the wildlife groups (bird and bat in particular) were limited. The bird and bat CRwo-soil values were generally lower than the ground-dwelling mammal and reptile CRwo-soil values based on the available data. Arithmetic mean CRwo-soil values for two species of native marsupial and two species of non-native placental were not significantly different (p < 0.05) when tested using a one-way analysis of variance. The results hinted at possible sampling efficiencies for terrestrial vertebrates. However, verification with additional data was recommended. Used cautiously, the CRwo-soil values may assist in environmental assessments of Australian uranium mining sites. They also enhance the available data on radionuclide transfer to wildlife for use internationally.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Metais/metabolismo , Radioisótopos/metabolismo , Vertebrados/metabolismo , Animais , Austrália , Pradaria
17.
Environ Pollut ; 246: 921-931, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31159142

RESUMO

As a result of their ubiquitous presence in the environment perfluoroalkyl acids (PFAAs) have been demonstrated in numerous organisms worldwide, in particular in those of higher trophic levels. The fact that PFAAs have been detected in various human matrices, together with the resultant potential human health risks, knowledge of possible paths of entry and distribution in various ecosystems, is of great importance. In this context pooled samples of terrestrial ecosystems - roe deer liver (n = 141), earthworms (n = 44) as well as leaves from beech and poplar trees (n = 70) - from the year 1989-2015 were obtained from the German Environmental Specimen Bank and examined for the presence of 11 PFAAs for the first time. In addition to determining individual and total PFAA concentrations, temporal trends have been deduced in order to determine the effectiveness of regulatory measures. The highest total mean concentration of PFAAs (sum of the concentrations of the 11 analytes) were 9.9 µg/kg in the roe deer liver samples, followed by earthworm samples with a mean PFAA concentration of 3.5 µg/kg and leaves with a mean total concentration of 2.5 µg/kg. In regard to temporal trends there was a significant reduction of concentrations for perfluorooctane sulfonate, perfluorooctanoic acid, perfluorononanoic acid and perfluorodecanoic acid in roe deer liver from 2003 to 2015, an indication of the effectiveness of regulatory measures. The same is true for the perfluorooctane sulfonate concentrations in earthworms and for perfluorooctanoic acid concentrations in the leaves. In contrast, an increase in perfluorobutanoic acid concentrations was observed from 2003 to 2015 in all three matrices. In summary it must be noted that in spite of the discernible effectiveness of minimization strategies, PFAAs are still detectable in terrestrial matrices and concentrations of other PFAAs as perfluorobutanoic acid appear to be increasing.


Assuntos
Ecossistema , Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Fluorcarbonetos/metabolismo , Animais , Cervos , Poluentes Ambientais/química , Fluorcarbonetos/química , Alemanha , Fígado/metabolismo , Oligoquetos/metabolismo , Folhas de Planta/metabolismo
18.
Chemosphere ; 233: 252-260, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31176126

RESUMO

Although 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (DDT) was banned in the United States in 1972, it is still often detected in sediments where pyrogenic carbonaceous matter (PCM) and sulfate-reducing bacteria (SRB) co-exist. In this study, we found that 70.2 ±â€¯0.2% of DDT disappeared in the presence of SRB and graphite powder, a model PCM, after 21 days at pH 7. Our results suggest that the observed DDT decay was due to the reaction between graphite powder and the reduced sulfur species that were produced by SRB. No biofilm formation was observed on the surface of graphite powder. Rather, the activity of SRB was inhibited by the presence of graphite powder. To understand the involvement of PCM in DDT decay, electrochemical cells and batch reactor experiments with sulfur-pretreated PCM as well as direct electrochemical reduction by a potentiostat were employed. Our results suggest that polysulfide, sulfide, sulfite, and thiosulfate could all react with PCM, forming surface-bound intermediates that subsequently led to DDT decay. The reactivity of reduced sulfur species was the highest for polysulfide, followed by sulfide, sulfite, and thiosulfate.


Assuntos
DDT/química , DDT/metabolismo , Desulfovibrio/metabolismo , Biodegradação Ambiental , Poluentes Ambientais/química , Poluentes Ambientais/metabolismo , Grafite , Sulfetos/química , Sulfetos/metabolismo , Sulfitos/química , Sulfitos/metabolismo , Tiossulfatos/química , Tiossulfatos/metabolismo
19.
Environ Int ; 129: 308-319, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31150973

RESUMO

The bacterial community from estuarine sediment undertakes the bioremediation and energy transformation of anthropogenic pollutants especially polycyclic aromatic hydrocarbons (PAHs). However, information and studies on bacterial synergism and related metabolic profiles under the stress of PAHs are limited. In this study, sediments from estuarine were collected and co-incubated with a classical PAH, pyrene. The results showed that Alpha- and Gammaproteobacteria became abundant at the late domesticating phase with the dominant genus of ZD0117, the uncultivated bacteria affiliated into Gammaproteobacteria. Functional gene analysis based on metagenomic sequencing showed that quantitatively changes of genes directly related to the degradation of aromatic hydrocarbon coordinated with genes involved into various metabolic pathways such as acylglycerol degradation, nitrogen fixation, sulfate transport system, Arnon-Buchanan cycle, and Calvin cycle (P < 0.01 and |ρ| > 0.8). Fifty-six metagenome-assembled genomes (MAGs) were reconstructed, which were primarily composed by Alpha- and Gammaproteobacteria. Bacteria belonging to the phylum Proteobacteria were found to be abundant in MAGs and contained genes encoding for dehydrogenase, which are key enzymes for pyrene degradation. In addition, genomes of uncultivated bacteria were successfully reconstructed and were proven to carry genes of synergistically metabolizing pyrene. Based on analysis of typical MAGs, the metabolic pathways involved in syntrophic associations of a pyrene-degrading consortium were reconstructed. The results in this study could make us fully understand the metabolic patterns of pyrene-degrading consortium from the estuarine sediment and widen the scope of functional bacteria.


Assuntos
Bactérias/metabolismo , Poluentes Ambientais/metabolismo , Pirenos/metabolismo , Bactérias/genética , Biodegradação Ambiental , Sedimentos Geológicos/microbiologia , Metagenômica , Microbiologia do Solo , Microbiologia da Água
20.
J Environ Sci (China) ; 83: 133-143, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221376

RESUMO

The degradation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) by Pycnoporus sanguineus was investigated in order to explore the impact of the heavy metal Cu2+ on BDE-47 decomposition and the subsequent formation of metabolites, as well as to further elucidate the degradation mechanism of BDE-47. An increase in degradation rate from 18.63% to 49.76% in the first four days and its stabilization at (51.26 ±â€¯0.08)% in the following days of BDE-47 incubation were observed. The presence of Cu2+ at 1 and 2 mg/L was found to promote the degradation rate to 56.41% and 60.79%, respectively, whereas higher level of Cu2+ (≥5 mg/L) inhibited the removal of BDE-47. The similar concentration effects of Cu2+ was also found on contents of fungal protein and amounts of metabolites. Both intracellular and extracellular enzymes played certain roles in BDE-47 transportation with the best degradation rate at 27.90% and 27.67% on the fourth and third day, individually. During the degradation of BDE-47, four types of hydroxylated polybrominated diphenyl ethers (OH-PBDEs), i.e., 6'-OH-BDE-47, 5'-OH-BDE-47, 4'-OH-BDE-17, 2'-OH-BDE-28, and two bromophenols, i.e., 2,4-DBP and 4-BP were detected and considered as degradation products. These metabolites were further removed by P. sanguineus at rates of 22.42%, 23.01%, 27.04%, 27.96%, 64.21%, and 40.62%, respectively.


Assuntos
Biodegradação Ambiental , Cobre/metabolismo , Poluentes Ambientais/metabolismo , Éteres Difenil Halogenados/metabolismo , Pycnoporus/metabolismo
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