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1.
Water Sci Technol ; 82(5): 851-860, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031065

RESUMO

The microalgae treatment system is an economically and environmentally friendly option for wastewater treatment. However, the effects of heavy metal toxicity on microalgae cells can limit the use of microalgae in the treatment of industrial effluents rich in heavy metals. In this work, we studied the effect of Ni, Cu, Al, Hg and Pb, added as single-metal solutions to the microalgae culture medium, on the growth of 20 indigenous strains belonging to a wide variety of microalgae genera. Ni and Cu were the most toxic to the strains tested. A highly tolerant strain of the Phacus genera was selected. We determined the effect of multiple combinations of Ni, Al and Pb on the cell growth of the selected strain and on the removal capacity of each metal from the microalgae culture medium. Phacus was able to grow in the multi-metal solution (Ni, 5.00 mg/L; Al, 9.94 mg/L and Pb 1.00 mg/L) and to efficiently remove the metals, with removal capacities of 8.82 ±0.16 mg/g for Ni, 2.09 ± 0.05 mg/g for Pb and 16.90 ± 0.53 mg/g for Al. The reductions of Ni, Al and Pb concentrations were 66.67, 64.28 and 79.17% respectively.


Assuntos
Metais Pesados , Microalgas , Biodegradação Ambiental , Chumbo/toxicidade , Metais Pesados/análise , Metais Pesados/toxicidade , Águas Residuárias
2.
Chemosphere ; 254: 126909, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957299

RESUMO

Soil contamination by heavy metals (HMs) is an environmental problem, and nanoremediation by using zero-valent iron nanoparticles (nZVI) has attracted increasing interest. We used ecotoxicological test and global transcriptome analysis with DNA microarrays to assess the suitability of C. elegans as a useful bioindicator to evaluate such strategy of nanoremediation in a highly polluted soil with Pb, Cd and Zn. The HMs produced devastating effect on C. elegans. nZVI treatment reversed this deleterious effect up to day 30 after application, but the reduction in the relative toxicity of HMs was lower at day 120. We stablished gene expression profile in C. elegans exposed to the polluted soil, treated and untreated with nZVI. The percentage of differentially expressed genes after treatment decreases with exposure time. After application of nZVI we found decreased toxicity, but increased biosynthesis of defensive enzymes responsive to oxidative stress. At day 14, when a decrease in toxicity has occurred, genes related to specific heavy metal detoxification mechanisms or to response to metal stress, were down regulated: gst-genes, encoding for glutathione-S-transferase, htm-1 (heavy metal tolerance factor), and pgp-5 and pgp-7, related to stress response to metals. At day 120, we found increased HMs toxicity compared to day 14, whereas the transcriptional oxidative and metal-induced responses were attenuated. These findings indicate that the profiled gene expression in C. elegans may be considered as an indicator of stress response that allows a reliable evaluation of the nanoremediation strategy.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Ferro/química , Metais Pesados/toxicidade , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Transcrição Genética/efeitos dos fármacos , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Ecotoxicologia , Nanopartículas Metálicas , Metais Pesados/análise , Estresse Oxidativo/genética , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Toxicogenética
3.
Ecotoxicol Environ Saf ; 203: 111037, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888596

RESUMO

Glacier studies as of late have ruffled many eyeballs, exploring this frigid ecology to understand the impact of climate change. Mapquesting the glaciers led to the discovery of concealed world of "psychrophiles" harboring in it. In the present study, the antibiotic resistance genes (ARGs) and heavy metal resistance genes (MRGs) were evaluated through both the culture-dependent and culture-independent methods. Samples were collected from two different glaciers, i.e., debris-covered glacier (Changme Khangpu) and debris-free glacier (Changme Khang). Functional metagenomics of both the glacier samples, provided evidence of presence of resistant genes against various antibiotic groups. Bacitracin resistant gene (bacA) was the predominant ARG in both the glaciers. MRGs in both the glacier samples were diversified as the genes detected were resistant against various heavy metals such as arsenic, tungsten, mercury, zinc, chromium, copper, cobalt, and iron. Unique MRGs identified from Changme Khangpu glacier were resistant to copper (cutA, cutE, cutC, cutF, cueR, copC, and copB) and chromium (yelf, ruvB, nfsA, chrR, and chrA) whereas, from Changme Khang glacier they showed resistance against cobalt (mgtA, dmef, corD, corC, corB, and cnrA), and iron (yefD, yefC, yefB, and yefA) heavy metals. ARGs aligned maximum identity with Gram-negative psychrotolerant bacteria. The cultured bacterial isolates showed tolerance to high concentrations of tested heavy metal solutions. Interestingly, some of the antibiotic resistant bacterial isolates also showed tolerance towards the higher concentrations of heavy metals. Thus, an introspection of the hypothesis of co-occurrence and/co-selection of ARGs and MRGs in such environments has been highlighted here.


Assuntos
Adaptação Biológica/genética , Antibacterianos/toxicidade , Resistência Microbiana a Medicamentos/genética , Poluentes Ambientais/toxicidade , Genes Bacterianos/efeitos dos fármacos , Camada de Gelo/microbiologia , Metais Pesados/toxicidade , Adaptação Biológica/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Camada de Gelo/química , Índia , Metagenômica , Siquim
4.
Ecotoxicol Environ Saf ; 203: 111055, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888617

RESUMO

The pollution level of potentially toxic elements (PTEs) in surface soils is detrimental to the ecosystem and human health. In this research, various indices such as an index of geo-accumulation (Igeo), contamination factor (CF), degree of contamination (DC), and principal component analysis (PCA) were implemented to identify and evaluate the soil PTEs pollution; and then human health risk assessment model used to establish the link between heavy metals pollution and human health in the urban region of south India. Results exhibited that the mean concentration of Cr, Cu, Ni and Zn were found to be 1.45-6.03 times greater than the geochemical background values. Cr and Cu were the most profuse PTEs measured in the soils. The pollution indices suggest that soil of the study region is mainly moderate to highly polluted. The non-carcinogenic health risk assessment proposed by the United States Environmental Protection Agency (USEPA) suggested the mean hazard indices (HIs) were below one which denotes no significant of non-carcinogenic risks to both children and adults. Furthermore, carcinogenic risk assessment results advised ~80% of cancer risk was caused by Cr contents, while other heavy metals indicate that neither children nor adults in the study region were of carcinogenic risks.


Assuntos
Carcinógenos/análise , Monitoramento Ambiental/métodos , Substâncias Perigosas/análise , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Adulto , Carcinógenos/toxicidade , Criança , Ecossistema , Substâncias Perigosas/toxicidade , Humanos , Índia , Metais Pesados/toxicidade , Medição de Risco , Poluentes do Solo/toxicidade , Estados Unidos , United States Environmental Protection Agency , Urbanização
5.
Chemosphere ; 258: 127412, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947661

RESUMO

The objective of this study was development of a simple and reliable microbial toxicity test based on fermentative bacteria to assess heavy metal (Hg2+, Cu2+, Cr6+, Ni2+, As5+, or Pb2+)-contaminated water. The dominant species of test organisms used in this study was a spore-forming fermentative bacterium, Clostridium guangxiense. Toxicity of water was assessed based on inhibition of fermentative gas production of the test organisms, which was analyzed via a syringe method. Overall, the fermentative bacteria-based test kits satisfactorily identified increased toxicity of water as water was contaminated with high amounts of heavy metals; however, levels of inhibition were dissimilar depending on the species of metals. Inhibitory effects of Hg2+, Cu2+, Cr6+, and Ni2+ were considerably greater than those of As5+ and Pb2+. The 24 h half-maximum effective concentrations (EC50) for Hg2+, Cu2+, Cr6+, Ni2+, As5+, and Pb2+ were analyzed to be 0.10, 0.51, 1.09, 3.61, 101.33, and 243.45 mg/L, respectively, confirming that Hg2+, Cu2+, Cr6+, and Ni2+ are more toxic to fermentative gas production than As5+ and Pb2+. The fermentative bacteria-based toxicity test represents an improvement over other existing toxicity tests because of ease of end-point measurement, high reproducibility, and favorable on-site field applicability. These advantages make the fermentative bacteria-based test suitable for simple and reliable toxicity screening for heavy metal-contaminated water.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Bactérias , Clostridium , Fermentação , Mercúrio/análise , Metais Pesados/análise , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise , Poluição da Água/análise
6.
Aquat Toxicol ; 227: 105594, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32911329

RESUMO

Diatoms are highly sensitive to perturbations in their environment and are thus useful as bioindicators for anthropogenic impacts such as pollution. However, there is no consensus about what aspects of diatom populations to measure (e.g., diversity, physiology, or morphology) and efficient and reliable survey protocols are lacking. Here, we evaluated the ecological status of diatom communities using both traditional and relatively novel methods on two islands (Deokjeok island and Daeijak island) affected by anthropogenic activities due to extensive agricultural practices and exploitation and that are under consideration for representative touristic sites in South Korea. Dissolved concentrations of metals and metalloid (As, Cu, Cr, Cd, Ni, Hg, Pb, and Zn) were below the ecological screening and toxicity reference values in water fractions but were above these values for sediment, particularly at one island, Deokjeok. The tested methods were generally consistent in finding little evidence for disruption of diatom communities, with dominance by Navicula and Gyrosigma, relatively high diversity, and typical abundance of lipid bodies and morphological deformities. However, analysis of lipid bodies and morphological deformities suggested greater potential anthropogenic disturbance at one site in Deokjeok. Future planning is required to ensure the maintenance of the near-pristine environments present on these islands.


Assuntos
Diatomáceas , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/toxicidade , Agricultura , China , Saúde Ambiental , Sedimentos Geológicos , Ilhas , Mercúrio/análise , Metais Pesados/toxicidade , República da Coreia , Medição de Risco
7.
Bull Environ Contam Toxicol ; 105(4): 565-571, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32918564

RESUMO

Fish consumption from contaminated water-bodies is a serious health issue. This study conducted to reveal the presence of heavy metals and bisphenols in Vembanad lake, an exploiting tourist spot in Kerala, receiving untreated agricultural, domestic, municipal, and industrial effluents. We evaluated aquatic contaminant impact on hepatic stress markers in Etroplus suratensis from fragile Vembanad lake. The significant difference in water physiochemical parameters, the concentration of heavy metals, and bisphenols (BPA and BPS) were studied. Hepatic tissue of E. suratensis inhabited in lake featured with high iron (11.29 ± 0.39 ppm) and BPA (0.02412 ± 0.0031 µg/mL) content along with an increased hepatic stress marker and distorted hepatic structure. The study highlights the presence of high iron and BPA in edible fish. The study recommends monitoring of physiochemical characters of freshwater lakes is essential for better survival of freshwater flora and fauna.


Assuntos
Compostos Benzidrílicos/toxicidade , Ciclídeos , Exposição Ambiental/efeitos adversos , Fígado/efeitos dos fármacos , Metais Pesados/toxicidade , Fenóis/toxicidade , Sulfonas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores , Feminino , Índia , Lagos , Fígado/anatomia & histologia , Fígado/metabolismo , Masculino
8.
J Environ Pathol Toxicol Oncol ; 39(2): 149-157, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32749124

RESUMO

Heavy-metal toxicity imposes a potential worldwide threat to the environment and humans. Cadmium, mercury, lead, and arsenic are nonessential toxic heavy metals that are most frequently involved in environmental and health hazards. Conventional chelating agents are unsuitable for subchronic and chronic heavy-metal toxicities. Scientific literature reveals that Spirulina (Arthrospira), a photosynthetic filamentous cyanobacterium that is generally known as blue-green algae, alleviates experimentally induced heavy-metal toxicity. The present review attempts to summarize such studies regarding cadmium, mercury, lead, and arsenic toxicity. A total of 58 preclinical studies demonstrate the alleviative effect of Spirulina against experimental arsenic, cadmium, lead, and mercury toxicities. Five clinical studies reported protective effects of Spirulina against arsenic toxicity in humans. Clinical studies against three heavy metals were not found in the literature. The present literature study appears to show that Spirulina possesses promising heavy-metal toxicity-ameliorative effects that are mainly attributed to its intrinsic antioxidant activity.


Assuntos
Intoxicação por Metais Pesados/prevenção & controle , Metais Pesados/toxicidade , Substâncias Protetoras/farmacologia , Spirulina , Animais , Arsênico/toxicidade , Suplementos Nutricionais , Intoxicação por Metais Pesados/tratamento farmacológico , Humanos
9.
Parasitol Res ; 119(10): 3297-3304, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32827105

RESUMO

A comparative study on the strobilar morphology of the tapeworm Proteocephalus percae (Müller, 1780) (Cestoda), a parasite of the perch Perca fluviatilis (L.), showed a high percentage of abnormally developed parasite individuals. The evaluation of biological samples showed seven types of morphological abnormalities, mostly related to reproductive organs of the model tapeworm species. The most commonly identified deformity was an incomplete segmentation of the strobila. A malformed ovary, which is a structural anomaly linked with proglottization and maturation of the strobila, was also shown to be rather frequent. Offish hosts (P. percae) were collected from two localities with different levels of heavy metal pollution, the highly contaminated water reservoir Ruzín and a control locality, the water reservoir Palcmanská Masa, which belongs to the European network of protected areas in Slovakia. Tapeworm abnormalities occurred more frequently in individuals from the contaminated environment (29.9%) compared with individuals from the control site (4.9%). The concentrations of heavy metals found in the parasites and their fish hosts from the heavily polluted reservoir support our assumption that the occurrence of abnormalities could be linked with the destructive effect of toxic substances. The present study also demonstrates that the enumeration of body deformities exceeding the common level of phenotypic variability of particular parasitic species could potentially be used as an indicator of environmental problems.


Assuntos
Monitoramento Biológico/métodos , Cestoides/anatomia & histologia , Infecções por Cestoides/veterinária , Doenças dos Peixes/parasitologia , Percas/parasitologia , Animais , Cestoides/efeitos dos fármacos , Infecções por Cestoides/parasitologia , Feminino , Metais Pesados/toxicidade , Eslováquia , Poluentes da Água/toxicidade
10.
Ecotoxicol Environ Saf ; 202: 110953, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800227

RESUMO

Heavy metal acclimated bacteria are profoundly the preferred choice for bioremediation studies. Bacteria get acclimated to toxic concentrations of heavy metals by induction of specific enzymes and genetic selection favoring new metabolic abilities leading to activation of one or several of resistance mechanisms creating bacterial populations with differences in resistance profile and/or level. Therefore, to use in bioremediation processes, it is important to discriminate acclimated bacterial populations and choose a more resistant strain. In this study, we discriminated heavy metal acclimated bacteria by using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and multivariate analysis methods namely Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA) and Soft Independent Modeling of Class Analogy (SIMCA). Two acclimation methods, acute and gradual, were used which cause differences in molecular changes resulting in bacterial populations with different molecular and resistance profiles. Brevundimonas sp., Gordonia sp., and Microbacterium oxydans were exposed to the toxic concentrations of Cd (30 µg/ml) or Pb (90 µg/ml) by using broth medium as a growth media. Our results revealed that PCA and HCA clearly discriminated the acute-acclimated, gradual-acclimated, and control bacteria from each other in protein, carbohydrate, and whole spectral regions. Furthermore, we classified acclimated (acute and gradual) and control bacteria more accurately by using SIMCA with 99.9% confidence. This study demonstrated that heavy metal acclimated and control group bacteria can be discriminated by using chemometric analysis of FTIR spectra in a powerful, cost-effective, and handy way. In addition to the determination of the most appropriate acclimation procedure, this approach can be used in the detection of the most resistant bacterial strains to be used in bioremediation studies.


Assuntos
Aclimatação/efeitos dos fármacos , Actinobacteria/efeitos dos fármacos , Caulobacteraceae/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Metais Pesados/toxicidade , Actinobacteria/crescimento & desenvolvimento , Biodegradação Ambiental , Caulobacteraceae/crescimento & desenvolvimento , Análise por Conglomerados , Meios de Cultura , Análise Multivariada , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier
11.
Ecotoxicol Environ Saf ; 202: 110954, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800228

RESUMO

Current study aims to determine difference in metal accumulation pattern in muscle of Liza parsia (pelagic, omnivore), Amblypharyngodon mola (surface feeder, herbivore) and Mystus gulio (benthic, carnivore) depending on their niche and feeding habit and how it affects the endogenous antioxidants and glucose metabolism in fish muscle. Fishes were collected from Malancha, Diamond Harbour and Chandanpiri, West Bengal, India. Concentrations of lead, zinc, cadmium, chromium were measured in water, sediment and fish muscle. Metal pollution index (MPI) and bioconcentration factor (BCF) was calculated to evaluate the ability of fish to accumulate specific metals in muscle tissue from the aquatic environment. Metal concentrations were found significantly higher (P < 0.05) in water, sediment, fish muscles from Malancha than Chandanpiri and Diamond Harbour. L. parsia (MPI: 0.4-1.6) showed highest metal deposition in their muscle followed by A. mola (MPI: 0.37-1.38) and M. gulio (MPI: 0.2-1.2). Malondealdehyde, superoxide dismutase, catalase, glutathione S transferase, glutathione reductase and cortisol levels increased in case of L. parsia from Malancha and Chandanpiri. Succinate dehydrogenase, lactate dehydrogenase, Ca+2 ATPase and cytochrome C oxidase levels were significantly (P < 0.05) lower at Malancha and Chandanpiri than Diamond Harbour. Heat shock protein (HSP70) expression was significantly (P < 0.05) higher in all fish species at Malancha followed by Chandanpiri and Diamond Harbour. Glucose, glycogen, hexokinase, phosphofructokinase and glycogen phosphorylase levels varied between sites and selected fish species. Serum cortisol level was measured and found to be the highest in L. parsia from Malancha (2.94 ± 0.12 ng/ml) and the lowest in M. gulio from Diamond Harbour (0.7 ± 0.05 ng/ml). The results indicate that metal toxicity alters antioxidant levels, oxidative status and energy production in fish in species specific manner. Our results also indicate that Mystus has the highest degree of adaptability in response to metal toxicity possibly due to its specific food habit and niche position. Therefore, it can be concluded that maintenance of oxidative and metabolic status to combat metal-induced oxidative load will be helpful for the fishes to acquire better resistance under such eco-physiological stress. Alteration of niche and interactive segregation in aquatic organism may be one of the key modulator of resistance against such stress.


Assuntos
Antioxidantes/metabolismo , Cyprinidae/metabolismo , Comportamento Alimentar/fisiologia , Glucose/metabolismo , Metais Pesados/toxicidade , Músculos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Cyprinidae/fisiologia , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Índia , Metais Pesados/metabolismo , Músculos/enzimologia , Músculos/metabolismo , Oxirredução , Especificidade da Espécie , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/metabolismo
12.
Bull Environ Contam Toxicol ; 105(3): 387-392, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32757041

RESUMO

Systematic studies on the impact of environmental pollution on the survival adaptability of amphibians are relatively few. In this study, Bufo raddei tadpoles from two places with totally different backgrounds of heavy metal pollution were chosen to explore the effects of heavy metal pollution on fitness and swimming performance of tadpoles, the physiological effects were investigated as well. The tadpoles at GS 25, GS 30 and GS 35 were collected randomly from the two study sites and were exposed to different environmental temperatures. The results showed that heavy metal enrichment and antioxidant levels were significantly higher in the tadpoles under long-term heavy metal stress. Meanwhile, heavy metal pollution affected the adaptability of tadpoles to environmental change and decreased the swimming performance of the tadpoles. Unexpected, the tadpoles from heavy metal-polluted area also showed some adaptive changes, mainly reflected in the increase in swimming endurance.


Assuntos
Larva/fisiologia , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bufonidae , Poluentes Ambientais , Poluição Ambiental , Larva/efeitos dos fármacos , Metais Pesados/análise , Natação
13.
Sci Total Environ ; 747: 141402, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-32771794

RESUMO

Heavy metals affect male reproductive function by impairing reproductive organs, disturbing reproductive hormone levels or directly affecting sperm quality. However, little attention has been given to the effect of environmental heavy metals on reproductive function in wild male birds. The present study investigated the alterations of reproductive function in male tree sparrows (Passer montanus) exposed to environments contaminated by heavy metals in terms of testis parameters, reproductive hormone levels and sperm movement characteristics. Two plots, Baiyin (BY, mainly polluted by copper, zinc, lead and cadmium) and Liujiaxia (LJX, a relatively unpolluted area) were selected as sampling sites. The results showed that tree sparrows from BY (1) accumulated higher levels of cadmium in the testes, (2) showed lower superoxide dismutase (SOD) activity and malondialdehyde level, with higher total antioxidant capacity and apoptosis level in the testes, (3) showed higher plasma levels of estrogen, follicle stimulating hormone and luteinizing hormone (LH), and (4) had better sperm movement performance. Additionally, we found that testis size, SOD activity in testes and LH levels were decisive factors in sperm movement performance in tree sparrows. Heavy metal concentrations in testes negatively correlated with testis size, SOD activity in testes, and estrogen levels in tree sparrows. The present study indicates that heavy metals accumulating in testes of tree sparrows adversely affected some key indicators of male reproductive function. However, testicular function, reproductive hormone levels and sperm quality showed adaptive responses that tended to partially compensate for the negative effects in the heavy metal polluted area. This study further indicated that the regulation of testicular function and reproductive hormone levels was the main factor for better sperm quality in tree sparrows exposed to environments contaminated by heavy metals.


Assuntos
Metais Pesados , Pardais , Animais , Cádmio , Poluição Ambiental/análise , Humanos , Masculino , Metais Pesados/análise , Metais Pesados/toxicidade , Motilidade Espermática
14.
Sci Total Environ ; 747: 141201, 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-32777500

RESUMO

Our work addresses a neglected aspect of heavy metal (HM) pollution of sediments in small floodplain reservoirs. Very little is known about this type of water bodies, in contrast to oxbow lakes or old river beds. The study examines the spatial horizontal distribution of HM and the effect of texture, organic carbon (OC) content, morphometric and location features on HM concentrations. Moreover, the data from the assessment of sediment toxicity were analysed with respect to recent years' droughts to estimate the potential toxicity of sediments as soils. The statistical analyses showed that the texture and the OC content had a significant impact on the HM concentrations. Fine-grained and OC-rich sediments exhibited higher HM pollution. Only one morphometric/location factor was shown to affect HM levels in sediments - the angle between the reservoir axis and the riverbed. The angle value affected the texture and, consequently, the HM content: with a rising angle the share of the coarse-grained fraction increased leading to a decrease in the HM concentration. The spatial horizontal HM distribution did not show statistically significant results, nonetheless, HM content was found to rise along with the distance from the initial part of reservoir. The toxicity levels were not exceeded in sediments, however, the evaluation of the material as soil showed that, according to European Union guidelines, the content of at least one HM was toxic in 80% of the samples. Contaminated floodplain reservoirs should be regarded as a double threat to riverine ecosystems. On the one hand, they are one of the main non-point sources of river valley pollution; on the other hand, given the drying up of reservoirs, sediments become soils and the soil-bound heavy metals become more toxic to the environment.


Assuntos
Metais Pesados , Poluentes Químicos da Água , China , Mudança Climática , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Metais Pesados/análise , Metais Pesados/toxicidade , Rios , Solo , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
15.
Ecotoxicol Environ Saf ; 205: 111149, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829210

RESUMO

Exposure to heavy metals was reported to be associated with heart rate variability (HRV) alteration. However, possible pathway of such association remains unclear. In this research, we investigated the possible role of lipid peroxidation in the associations between urinary heavy metals and HRV. We performed a cross-sectional study using baseline data of Wuhan-Zhuhai cohort. Urinary heavy metals (including lead, barium, antimony, cadmium, zinc, copper, iron and manganese), urinary 8-iso-prostaglandin-F2α levels (common biomarker for lipid peroxidation) and HRV indices (SDNN, r-MSSD, low frequency, high frequency and total power) were measured among 3022 participants. We conducted multivariable linear regression models to quantify associations between urinary 8-iso-prostaglandin-F2α (8-iso-PGF2α) and heavy metals or HRV indices. The potential role of 8-iso-PGF2α in the association of urinary heavy metals with HRV was evaluated through mediation analyses. After adjusting for potential confounders, urinary manganese, iron, copper, zinc, cadmium, antimony and barium were identified to be negatively associated with one or more HRV parameters. Each one-unit growth of log-transformed levels of urinary manganese, iron, copper, zinc, antimony and barium was associated with a 1.9%, 1.5%, 4.7%, 4.0%, 2.7% and 1.3% decrease in SDNN, respectively. We observed positive dose-response relationships between all eight urinary heavy metals and 8-iso-PGF2α, as well as negative association of urinary 8-iso-PGF2α with SDNN and total power (all P trend<0.05). The proportions mediated by 8-iso-PGF2α on SDNN were 4.6% for manganese, 9.3% for iron, 19.8% for antimony and 11.0% for barium. The proportions mediated by 8-iso-PGF2α on total power were 6.9% for manganese and 10.1% for cadmium (all P value < 0.05). This study suggested that urinary manganese, iron, copper, zinc, cadmium, antimony and barium were negatively associated with HRV indices. Lipid peroxidation may partly mediate the associations of urinary manganese, iron, cadmium, antimony and barium with specific HRV indices.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/toxicidade , Frequência Cardíaca , Peroxidação de Lipídeos , Metais Pesados/toxicidade , Adulto , Antimônio , Biomarcadores/metabolismo , Cádmio , Cobre , Estudos Transversais , Dinoprosta/análogos & derivados , Exposição Ambiental/análise , Poluentes Ambientais/metabolismo , Feminino , Humanos , Ferro , Masculino , Manganês , Metais Pesados/metabolismo , Pessoa de Meia-Idade , Zinco
16.
Ecotoxicol Environ Saf ; 204: 111065, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32784014

RESUMO

In the present study, chemical analysis of contaminants (three classes of organic pollutants and seven metals) and elutriate toxicity test were adopted to evaluate the potential environmental hazards of dredged sediment samples from five sites (SS1-5) along Huangpu River Channel (Shanghai Harbor, China). The metal Pb, Cu, Cr, Zn and the organic pollutants including total hexachlorocyclohexane (HCHs) and total dichlorodiphenyltrichloroethane (DDTs) in the five samples exceeded the threshold for effects level (TEL) to varying degrees. The probable effect concentration quotients (QPECm) of contaminants from the five dredged samples were all above 0.25, which means potential toxicity risks. Elutriate toxicity tests using medaka fish (Oryzias melastigma) and manila clam (Ruditapes philippinarum) showed that SS2 caused mortality to both species and SS1 caused mortality to fish. To explore the molecular biomarkers that may reflect the toxic effects, differential expressed genes were identified by RNA-Seq-based transcriptome profiling from the survived clams exposed to the two polluted elutriates (SS1, SS2). In clams exposed to SS1 and SS2 elutriate, 368 and 860 differential expressed genes (DEGs) were up-regulated, 199 and 1304 genes were down-regulated, respectively. Fourteen DEGs were selected from the enriched pathways that reflect cytotoxicity and responses to xenobiotics for the following quantitative real time PCR analysis. The transcriptomic profiling and the selected gene's expression patterns from clams exposed to SS1 and SS2 showed significant differences with the non-contaminated and control groups. Using the expression data of the selected gene battery in Factor Analysis allowed the discrimination between contaminated and non-contaminated sites and may reflect an influence gradient of sites. The development of the assay of these molecular biomarkers may provide a rapid and high-throughput tool for the quality assessment of the dredging sediments.


Assuntos
Bivalves/efeitos dos fármacos , Monitoramento Ambiental/métodos , Expressão Gênica/efeitos dos fármacos , Sedimentos Geológicos/química , Rios/química , Poluentes Químicos da Água/toxicidade , Animais , Bivalves/genética , China , DDT/toxicidade , Hexaclorocicloexano/toxicidade , Metais Pesados/toxicidade , Testes de Toxicidade
17.
Ecotoxicol Environ Saf ; 204: 111083, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32791359

RESUMO

Due to the accumulation of heavy metals in soil ecosystems, the response of soil microorganisms to the disturbance of heavy metals were widely studied. However, little was known about the interactions among microorganisms in heavy metals and total petroleum hydrocarbons (TPH) co-contaminated soils. In the present study, the microbiota shifts of 2 different contamination types of heavy metal-TPH polluted soils were investigated. NGS sequencing approach was adopted to illustrate the microbial community structure and to predict community function. Networks were established to reveal the interactions between microbes and environmental pollutants. Results showed that the alpha diversity and OTUs number of soil microbiota were reduced under heavy metals and TPH pollutants. TPH was the major pollutant in HT1 group, in which Proteobacteria phylum increased significantly, including Arenimonas genus, Sphingomonadaceae family and Burkholderiaceae family. Moreover, the function structures based on the KEGG database of HT1 group was enriched in the benzene matter metabolism and bacterial motoricity in microbiota. In contrast, severe Cr-Pb-TPH co-pollutants in HT2 increased the abundance of Firmicutes. In details, the relative abundance of Streptococcus genus and Bacilli class raised sharply. The DNA replication functions in microbiota were enriched under severely contaminated soil as a result of high concentrations of heavy metals and TPH pollutants' damage to bacteria. Furthermore, according to the correlation analysis between microbes and the pollutants, Streptococcus, Neisseria, Aeromonas, Porphyromonas and Acinetobacter were suggested as the bioremediation bacteria for Cr and Pb polluted soils, while Syntrophaceae spp. and Immundisolibacter were suggested as the bioremediation bacteria for TPH polluted soil. The study took a survey on the microbiota shifts of the heavy metals and TPH polluted soils, and the microbe's biomarkers provided new insights for the candidate strains of biodegradation, while further researches are required to verify the biodegradation mechanism of these biomarkers.


Assuntos
Hidrocarbonetos/toxicidade , Metais Pesados/toxicidade , Microbiota/efeitos dos fármacos , Petróleo/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Solo/química , Biodegradação Ambiental , Firmicutes/efeitos dos fármacos , Firmicutes/metabolismo , Hidrocarbonetos/análise , Metais Pesados/análise , Petróleo/análise , Poluição por Petróleo/análise , Proteobactérias/efeitos dos fármacos , Proteobactérias/metabolismo , Poluentes do Solo/análise
18.
Sci Total Environ ; 746: 141254, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32768788

RESUMO

Microplastics (MPs) are gradually spreading around the world and becoming a ubiquitous environmental contamination in aquatic environments. Due to its unique physicochemical properties, MPs are considered to be strong adsorbents for environmental pollutants and may affect their fate and toxicity in the environment. In this study, the adsorption behaviors of four typical heavy metal ions (Pb2+, Cu2+, Cd2+, and Ni2+) on two sizes of polystyrene MPs (10 µm and 50 µm) were investigated based on batch experiments, and the combined effects of heavy metals and MPs were assessed using Daphnia magna as model. The results showed that smaller MPs (SMPs) exhibited higher adsorption capacities for metal ions (0.261-0.579 mg/g) than that of the larger MPs (LMPs) (0.243-0.525 mg/g), and the affinity sequence of heavy metals on MPs is Pb2+ > Cu2+ > Cd2+ > Ni2+. There are better admirable agreements for pseudo-second-order model and Langmuir model to fit the adsorption kinetics and adsorption isotherms, respectively. Additionally, the combined toxicity of MPs and heavy metals was negatively correlated with the adsorption capacity between them. The combined effects of mixtures toward D. magna changed from antagonism to additive effect with increasing MPs concentrations, and SMPs exhibited higher toxicological risk than LMPs. Our findings compared the accumulative effects of various heavy metals on MPs and can contribute to understanding the combined effects of plastics and heavy metals on biota.


Assuntos
Metais Pesados/toxicidade , Microplásticos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Adsorção , Animais , Daphnia , Microplásticos/toxicidade , Plásticos
19.
Aquat Toxicol ; 227: 105587, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32841885

RESUMO

Among the various environmental disturbances caused by wildfires, their impacts within burnt areas and on the downhill aquatic ecosystems has been receiving increased attention. Post-fire rainfalls and subsequent runoffs play an important role in transporting ash and soil to aquatic systems within the burnt areas. These runoffs can be a diffuse source of toxic substances such as metals. The present work aims at assessing the effects of ash-loaded runoff on feeding rates of three representative aquatic invertebrates (Daphnia magna, Corbicula fluminea and Atyaephyra desmarestii) and the mosquitofish, Gambusia holbrooki, through post-exposure feeding inhibition bioassays carried out in-situ and in the laboratory using water collected from the experimental field sites. Four sites were selected in a partially burnt basin for bioassay deployment and sample collection: one site upstream of the burnt area (RUS); three sites receiving runoff directly from the burnt area, one immediately downstream of the burnt area (RDS) and two in permanent tributary streams within the burnt area (BS1 and BS2). The in-situ exposure lasted four days and began following the first post-fire major rain events. At sites affected by the wildfire, post-exposure feeding rates for D. magna, A. desmarestii and G. holbrooki were lower, which is consistent with the highest levels of metals found at these sites compared to the unaffected site, although the individual concentrations of each metal were generally below corresponding ecological safety benchmarks. Thus, interactions between metals and/or between metals and other environmental parameters certainly played a role in modulating the ecotoxic effects of the runoffs; this was further supported by a Toxic Units Summation exercise. Even if direct causal links between the ecotoxicological effects observed in D. magna, A. desmarestii and G. holbrooki and the physicochemical parameters of the water samples could not be established, the results suggest an important role of major and trace elements in explaining post-exposure feeding rate variation.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Cinza de Carvão/toxicidade , Comportamento Alimentar/efeitos dos fármacos , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Incêndios Florestais , Animais , Organismos Aquáticos/fisiologia , Bioensaio , Corbicula/efeitos dos fármacos , Ciprinodontiformes/fisiologia , Daphnia/efeitos dos fármacos , Ecossistema , Ecotoxicologia , Água Doce/química , Modelos Teóricos , Portugal , Oligoelementos/toxicidade
20.
PLoS One ; 15(8): e0237031, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790698

RESUMO

Tomato is the most widespread vegetable crop in the world. In Italy, tomatoes are mainly cultivated in the South and in the Campania region, precisely in the area called Agro Nocerino-Sarnese. This flatland is affected by an extreme level of environmental degradation, especially related to the Sarno River, where concentrations of Potential Toxic Elements (PTEs) have been found to be higher than the maximum permitted level. The aim of this study was to determine the PTEs uptake by roots and their translocation to the aerial parts of the plants of two cultivars of tomatoes (Pomodoro Giallo and San Marzano Cirio 3). To the purpose, samples of the two cultivars were grown both in pots with experimentally contaminated soil containing: Cr or Cd or Pb at extremely high concentrations and in pots with uncontaminated soils (control). Additionally, the antioxidant properties of the cultivars selected grown on uncontaminated/contaminated soils were assessed. The results showed that Cd was the contaminant that most significantly interfered with the growth of both cultivars of tomato plants, whereas Pb caused lower phenotypical damage. Cd translocation from root to the organs of tomato plants was observed in both cultivars. Specifically, the total amount of Cd found in stems and leaves was higher in the Pomodoro Giallo (254.4 mg/kg dry weight) than in the San Marzano Cirio 3 (165.8 mg/kg dry weight). Cd was the only PTE found in the fruits of both cultivars, with values of 6.1 and 3.9 mg/kg dry weight of Pomodoro Giallo and San Marzano Cirio 3, respectively. The fruits of tomato plants grown in PTEs-contaminated soil showed inhibition or stimulations of the radical scavenging activity compared to the fruits grown in uncontaminated soil. This study highlighted that, despite the relatively high experimental concentrations of PTEs, their translocation to the edible part was comparatively low or absent.


Assuntos
Lycopersicon esculentum/metabolismo , Metais Pesados/farmacocinética , Poluentes do Solo/farmacocinética , Bioacumulação , Transporte Biológico Ativo , Cádmio/farmacocinética , Cádmio/toxicidade , Cromo/farmacocinética , Cromo/toxicidade , Depuradores de Radicais Livres/metabolismo , Radicais Livres/metabolismo , Itália , Chumbo/farmacocinética , Chumbo/toxicidade , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/crescimento & desenvolvimento , Metais Pesados/toxicidade , Poluentes do Solo/toxicidade , Distribuição Tecidual
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