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1.
Environ Monit Assess ; 192(11): 671, 2020 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-33009943

RESUMO

Plastic pollution is an emerging issue faced worldwide owing to rapid urbanization and extensive use of plastic products. The objective of this study was to determine and highlight the spatial distribution of microplastics (MPs) in the top soils of different land use types of an urbanized city, i.e., Lahore, Pakistan, influenced by different human activities. Soil samples (n = 40) were collected from eight different land use groups including agricultural areas, drains, dumping sites, industrial areas, lawns, parks, roadsides, and wastelands to represent the influence of corresponding human actions. After cleaning the samples through wet peroxide digestion and density separation, MPs were identified under a stereomicroscope. The range of MPs in top soils within Lahore district varied from 1750 to 12,200 MPs/kg with an average of 4483 ± 2315 MPs/kg. The highest concentration of MPs was present in the parks while the lowest numbers of MPs were enumerated in soil from dumping sites. About 99% of the identified MPs particles were fibers, sheets, and fragments in shape while foams and beads accounted for the rest. Moreover, among the size ranges, the large size MPs (300-5000 µm) were found in the majority (41.16%) followed by the fine size MPs (50-150 µm; 30.67%) and medium size MPs (150-300 µm; 28.17%). The current level of MPs pollution attracts the attention of researchers for a more comprehensive investigation in the future. It also incites the policy-makers to implement the regulations to prevent plastic pollution and its environmental implications.


Assuntos
Solo , Poluentes Químicos da Água/análise , Cidades , Monitoramento Ambiental , Humanos , Microplásticos , Paquistão , Plásticos
2.
J Environ Qual ; 49(1): 119-127, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016350

RESUMO

Eutrophication is an issue of concern in many brackish lakes with an agricultural watershed. The amount of snowfall in snowy areas is anticipated to decline because of global climate change. The aim of this study was to assess the impact of changes in the inflow of snowmelt on the nutrient concentrations of a downstream brackish lake. In Lake Ogawara, a brackish lake in a snow-covered agricultural area of Japan, we examined the relationships between inflowing river discharge (D/C) during spring and total nitrogen (TN) and total phosphorus (TP) concentrations in the mixolimnion of the lake ([TNmix ] and [TPmix ], respectively) using 29 yr of monitoring data. In addition, we assessed the causal relationship between the D/C and the lake nutrient concentrations. There was large year-to-year variation in D/C during April (D/CApr ), which accounted for 7-31% of the mixolimnion volume. Significant positive correlations were observed between D/CApr and [TNmix ] from the ensuing April to September. On an annual basis, 49% of the interannual variation of the mean [TNmix ] during the ensuing April to September was explained by the interannual variation of D/CApr . Therefore, D/CApr could be useful as a simple index to [TNmix ] in the ensuing spring to summer. It is notable that the relationships between D/CApr and [TNmix ] from April to September was indicated to be acausal by statistical causal inference. Common climate conditions that increase D/CApr (i.e., a cold winter with a high level of precipitation) were found to drive other biogeochemical processes that increased [TNmix ] during the ensuing spring to summer.


Assuntos
Lagos , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Nitrogênio/análise , Fósforo/análise
3.
J Environ Qual ; 49(1): 128-139, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016363

RESUMO

The Variable Volume Water Model (VVWM), the receiving water body model for the USEPA regulatory assessment of aquatic pesticide exposures, is composed of a set of static and quasistatic receiving water body conceptual models, but research comparing performance of these models to observations is limited. The water body models included are the constant volume (CVol), constant volume with overflow (CVO), and varying volume with overflow (VVO) models. This work quantified the performance of these three VVWM conceptual models compared with atrazine observations in 50 community water systems (CWSs), and the effect of alternative conceptual models on estimated environmental concentrations of pesticides in regulatory screening assessments. The 50 selected CWSs most relevant to the static and quasistatic VVWM concepts were small in size, with estimated time to peak flow of <1.5 d for consistency with the daily runoff assumption in USEPA landscape Pesticide Root Zone Model (PRZM). The CVO and VVO conceptual models resulted in similar distributions of bias across CWSs with the median result being close to no bias, but the CVol model resulted in overestimation in the majority of CWSs with median model bias near three times the observed values. At present, the CVol conceptual model parameterized with conservative input assumptions has been the regulatory standard invoked in VVWM, yet our results showed that a more physically correct conceptual model (CVO or VVO) could be invoked in regulatory exposure modeling for ecological risk assessment, reducing structural model bias while still allowing users to introduce conservative model inputs for screening purposes.


Assuntos
Atrazina , Praguicidas/análise , Praguicidas/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Modelos Teóricos , Água
4.
J Environ Qual ; 49(1): 152-162, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016367

RESUMO

Pesticides are important for agriculture in the United States, and atrazine is one of the most widely used and widely detected pesticides in surface water. A better understanding of the mechanisms by which atrazine and its degradation product, deethylatrazine, increase and decrease in surface waters can help inform future decisions for water quality improvement. This study considers causal factors for trends in pesticide concentration in U.S. streams and models the causal factors, other than use, in structural equation models. The structural equation models use a concomitant trend in corn (Zea mays L.) and a latent variable model, indicating moisture supply and management. The moisture supply and management latent variable model incorporates long-term moisture conditions in the individual watersheds by using the Palmer hydrologic drought index, human influence on the hydrologic cycle through the percentage of the watershed drained by tile drains in 2012, and the base-flow contribution to streamflow, using the base-flow index. The structural equation models explain 77 and 38% of the variability in atrazine and deethylatrazine trends, respectively, across the conterminous United States. The models highlight future water quality challenges, particularly in tile-drained settings where fall precipitation and heavy precipitation are increasing.


Assuntos
Atrazina/análise , Praguicidas/análise , Poluentes Químicos da Água/análise , Agricultura , Atrazina/análogos & derivados , Estados Unidos
5.
J Environ Qual ; 49(3): 654-662, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016401

RESUMO

Continuous-flow iron and bio-iron columns were used to evaluate the effects of seepage velocity and concentration on Cr(VI) removal from groundwater. Solid-phase analysis showed that microorganisms accelerated iron corrosion by excreting extracellular polymeric substances and generated highly reactive minerals containing Fe(II), which gave the bio-iron column a longer life span and enhanced capacity for Cr(VI) removal via enhanced adsorption and reduction by reactive minerals. The bio-iron column showed much higher Cr(VI) removal capacity than the iron column with increasing Cr(VI) loading, which was obtained by increasing the seepage velocity or influent Cr(VI) concentration from 95 to 1138 m yr-1 and from 5 to 40 mg L-1 , respectively. When the Cr(VI) loading varied in a range of 0 to 10 mg L-1 h-1 , the bio-iron column had a 60% longer longevity and one- to sixfold higher Cr(VI) elimination capacity than the iron column. This result indicated that, under fluctuating hydraulic conditions [e.g., seepage velocity and Cr(VI) concentration], the presence of microorganisms can significantly boost Cr(VI) removal using Fe0 -based permeable reactive barriers.


Assuntos
Água Subterrânea , Poluentes Químicos da Água/análise , Adsorção , Cromo , Ferro
6.
J Environ Qual ; 49(5): 1322-1333, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33016441

RESUMO

Antibiotics and estrogens are recognized as emerging contaminants in the water environment because of their potentially adverse effects on aquatic ecosystems. The concentrations of four steroid estrogens (17α-estradiol, 17ß-estradiol, estrone, and estriol) and eight antibiotics (norfloxacin, levofloxacin, ciprofloxacin, enrofloxacin, metronidazole, sulfapyridine, doxycycline, and sulfamethoxazole) in the Chaohu Lake basin in Anhui province, China, were analyzed along with adjacent wastewater. The levels of the target antibiotics and estrogens were below detection limits (not detected [nd])-89.86 and nd-118.09 ng L-1 , respectively, in the lake water. All of the target antibiotics and estrogens were detected in sediment, and the concentrations ranged widely (nd-35,544 and nd-16,344 ng kg-1 , respectively). Antibiotics and estrogens varied spatially in the study area and mostly came from untreated wastewater. Antibiotics and estrogens were associated with water parameters such as pH and total nitrogen. A significant positive correlation was observed between estriol and levofloxacin concentrations (r = .65; p < .01), indicating that levofloxacin from the same source might have inhibited the microbiological degradation of estriol in the surface water. Overall, the estrogens pose a more severe risk than antibiotics to the Chaohu Lake system. However, co-occurrence of antibiotics may affect the fate of estrogens in the same lake media. More attention should be given to estrogens than to antibiotics in wastewater-affected lake systems.


Assuntos
Águas Residuárias , Poluentes Químicos da Água/análise , Antibacterianos/análise , China , Ecossistema , Monitoramento Ambiental , Estrogênios/análise , Lagos/análise
7.
Environ Monit Assess ; 192(11): 685, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33026535

RESUMO

The Anzali wetland (located in northern Iran) and many parts of its catchment are considered important habitats for the swan mussel (Anodonta cygnea). The habitat of this native bioindicator mussel is being threatened in many locations of the catchment due to various anthropogenic activities. The present study aimed to apply a classification tree model (J48 algorithm) to predict the habitat preferences of A. cygnea in 12 sampling sites based on various water quality and physical-habitat variables. The species was present in 50% of sampling sites, while it was absent in the remaining of the sampling sites. In total, 144 samples of A. cygnea (72 presence and 72 absence instances) were monthly measured together with the abiotic variables during 1-year study period (2017-2018). For the CT model, two-thirds of datasets (96 instances) served as a training and the remainder was employed for the validation set (48 instances). Among 25 environmental variables introduced to the model (with pruning confidence factor = 0.10, threefold cross-validation and 5 times randomization effort), the validity of 6 variables was confirmed by the model in all three subsets. Water salinity, flow velocity, water depth and water turbidity were jointly predicted by the model in three subsets. The model predicted that the absence of A. cygnea might be associated with increasing flow velocity, total phosphate and water turbidity. In contrast, the presence of A. cygnea might be related to decreased water depth and increased calcium concentration. The model also confirmed that all predicted variables for the species might be completely dependent on the water salinity. According to the chi-square test (x2 = 26.53, p < 0.05), the habitat condition of A. cygnea is influenced by significant variations in the spatio-temporal patterns.


Assuntos
Anodonta , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Irã (Geográfico) , Poluentes Químicos da Água/análise
8.
Environ Monit Assess ; 192(11): 683, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33026556

RESUMO

The main objective of this research was to investigate the impact of the construction of Karkheh Dam in 2001 (referred to as the intervention time), on groundwater quality. The time series of total dissolved solids (TDS) and other water quality data including potassium (K+), sodium (Na+), magnesium (Mg2+), calcium (Ca2+), bicarbonate (HCO3-), sulfate (SO42-), and chloride (Cl-) for the period between 1996 and 2012 were analyzed. The magnitude of the trend by Sen's slope estimator for HCO3-, SO42-, and TDS was 0.005, - 0.02 and - 3.04, where a decline expected for SO42- and TDS, whereas for HCO3-, an increase was expected. According to the Pettitt's test, the mean of TDS decreased from 2306.9 mg/l between 1996 and 2002 to 797.2 mg/l between 2002 and 2012. During this time, the standard deviation of TDS declined from 2187.1 to 132.0 mg/l. The results of change point detection by the Pruned Exact Linear Time (PELT) algorithm were consistent with that of Pettitt's test providing confirmation that a change point in Ca2+, Mg2+, SO42-, and TDS time series data occurred in 2002.The findings from intervention analysis using the Bayesian structural time series (BSTS) technique showed that TDS concentration during the post-intervention period had an average value of 1127 mg/l compared with 1972 mg/l, before the dam construction. The time series of TDS demonstrated a decrease of about 43% following the intervention time.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Teorema de Bayes , Monitoramento Ambiental , Irã (Geográfico) , Poluentes Químicos da Água/análise
9.
Water Sci Technol ; 82(5): 829-842, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031063

RESUMO

A high-surface-area and inexpensive activated carbon has been produced from lemon peel using chemical activation with H3PO4 at 500 °C in a N2 atmosphere. Afterwards, the synthesized cobalt nanoparticles using coprecipitation method were adsorbed on the activated carbon surface, and as a result magnetic activated carbon was obtained. Sample characterization has been assessed via X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption and magnetic properties. It was found that magnetic activated carbon-cobalt nanoparticles (MAC/Co) synthesized had a high saturation magnetization. The MAC/Co revealed super-paramagnetic behaviors at room temperature, and have been readily isolated from solution by using an exterior magnet. Next, adsorption behavior of malachite green and Pb(II) onto the generated MAC/Co has been examined. Sorption kinetics and equilibrium have been studied using batch procedure. The kinetic and isothermal adsorption results were matched completely with the Elovich and Langmuir models, respectively. Based on the Langmuir model, the highest adsorption capacities of malachite green dye and Pb(II) ion respectively were 263.2 and 312.5 mg g-1 at room temperature. Based on the results, the MAC/Co is a probable economic and effective adsorbent that can be employed as a new adsorbent to remove malachite green dye and Pb(II) from wastewater.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Carvão Vegetal , Cobalto , Chumbo , Fenômenos Magnéticos , Corantes de Rosanilina , Águas Residuárias , Poluentes Químicos da Água/análise
10.
Water Sci Technol ; 82(5): 843-850, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031064

RESUMO

Qualitative and quantitative analysis of trace organics in the condensate and its correlation with chemical oxygen demand (COD) is the key to the research on the reuse technology of condensate (condensate) from natural gas to hydrogen production process. The contents of anions, COD, total organic carbon (TOC) and total nitrogen (TN) were measured by ion chromatography and the TOC analyzer. Trace organics in the condensate and its correlation with COD was investigated in this paper. Results show that the contents of COD and TOC is 74.1 and 17.81 mg/L, respectively, and the anions in the condensate are mainly Cl-, I-, and SO42-, etc. The condensate mainly contains small molecule organics including methanol, ethanol and formic acid with the content of 41.4, 2.1 and 3.2 mg/L, respectively. The spiked recovery of methanol, ethanol and formic acid is 96.1%, 100.2% and 103.9% by high performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. Methanol is the main source of COD in the condensate, and the contribution rate reaches up to 83.8%. The removal of trace methanol can significantly reduce the COD of the condensate. This work might provide basic data for reasonable recovery and utilization of condensate in the hydrogen production process.


Assuntos
Gás Natural , Poluentes Químicos da Água , Análise da Demanda Biológica de Oxigênio , Hidrogênio , Nitrogênio , Poluentes Químicos da Água/análise
11.
Water Sci Technol ; 82(5): 877-886, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031067

RESUMO

Water pollution from antibiotics has attracted a lot of attention for its serious threat to human health. In this study, a magnetic adsorbent (zinc ferrite/activated carbon (ZnFe2O4/AC) was synthesized via microwave method to effectively remove gemifioxacin mesylate (GEM) and moxifloxacin hydrochloride (MOX). Based on the porosity of AC and the magnetism of ZnFe2O4, the resulting ZnFe2O4/AC has high adsorption capacities and can be easily separated from the solid-liquid system via a magnetic field. The largest adsorption capacities for GEM and MOX can reach up to 433.4 mg g-1 and 388.8 mg g-1, respectively, higher than those of reported adsorbents such as MIL-101 and MOF-808. Fastest adsorptions of GEM and MOX were found at 5 min, and solution pH and coexisting salts do not have a significant influence on the adsorption process. The adsorption mechanism analysis indicates that electrostatic interaction and H-bond interaction contribute to the effective adsorption.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Antibacterianos , Magnetismo
12.
Water Sci Technol ; 82(5): 998-1008, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031076

RESUMO

The feasibility of an advanced oxidation process based upon sodium persulfate (SPS) activated simultaneously by heat (50 °C) and nanoscale zero-valent iron (nZVI) on benzene removal was investigated. The experimental results strongly showed the synergistic effect of thermal and nZVI activation to SPS and benzene removal was enhanced with the increase of SPS/nZVI/benzene molar ratio. Specifically, 94% of benzene could be removed in 1 hr at 50 °C at the SPS/nZVI/benzene molar ratio of 10/5/1. The radical scavenger tests and electron paramagnetic resonance (EPR) analysis confirmed that SO4•- was the predominant species contributing to benzene degradation. Further, the effects of the solution matrix on benzene elimination were investigated. The results indicated that benzene destruction in the thermally activated SPS/nZVI system performed better under acidic conditions, and the high concentration of both Cl- and HCO3- had adverse effects on benzene elimination. The test for the performance of benzene degradation in the actual groundwater demonstrated that benzene could be degraded entirely at SPS/nZVI/benzene molar ratio of 40/40/1 at 50 °C, indicating that the synergistic catalysis of thermal and nZVI activation to SPS is exploitable and the thermally activated SPS/nZVI system can be applicable to the remediation of benzene contaminated groundwater.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Benzeno , Ferro , Oxirredução , Poluentes Químicos da Água/análise
13.
Water Sci Technol ; 82(6): 1031-1043, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33055394

RESUMO

This study evaluated the capacity of a pilot-scale high-rate algal pond (HRAP) to remove pharmaceutical compounds (PCs) from domestic wastewater in the city of Santiago de Cali, Colombia. The compounds analyzed included antiepileptics, hypolipidemic drugs, tranquilizers and analgesics, and anti-inflammatory drugs. The HRAP operated under a continuous water flow of 0.2 m3d-1 and a 3-day hydraulic retention time (HRT). Removal efficiencies were high (>70%) for fenofibric acid, ibuprofen, and paracetamol; medium (30-70%) for gabapentin, lamotrigine, fenofibrate, gemfibrozil, diclofenac, ketoprofen, naproxen, and pentoxifylline; and low (<30%) for carbamazepine and its metabolite 10,11-Dihidro-10,11-dihidroxicarbamazepine (CBZ-Diol). The findings herein are similar to other studies, but were obtained with a shorter HRT. These results show that tropical environmental conditions favor photodegradation and contribute to the development of microalgae and the biodegradation process. Twenty microalgae species were identified, with the phylum Chlorophyta as the most abundant, particularly due to its natural introduction. The removal of the PCs also reflected a percentage reduction (>50%) in the ecological hazard posed by most of the compounds, although it is important to note that the hazard from gemfibrozil and ibuprofen remained high even after treatment, indicating the need for complementary treatment.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Colômbia , Tanques , Clima Tropical , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/análise
14.
Environ Monit Assess ; 192(11): 704, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33057810

RESUMO

Mercury (Hg) was measured in the muscle, liver, and gonads of Haemulopsis elongatus and Pomadasys macracanthus from Mazatlán (SE Gulf of California) to determine the relationships of the hepatosomatic index (HSI) and gonadosomatic index (GSI) of fish with Hg concentrations in the corresponding tissues. Health risk to consumers was assessed by using the hazard quotient (HQ), considering the average rate of fish consumption in Mexico and Hg concentration in the edible tissue. In H. elongatus, the highest Hg levels were measured in the liver (3.748 µg g-1); in P. macracanthus, the highest Hg concentration was quantified in the muscle (0.574 µg g-1). In P. macracanthus, the HSI was negatively correlated with Hg concentration in the liver; in H. elongatus, there was also a negative relationship between Hg levels in gonads and the GSI. Mean HQ values in Haemulopsis elongatus (0.005) and Pomadasys macracanthus (0.002) were below the value (HQ ≥ 1) of concern. The significant reduction of HSI and GSI with Hg increase in the liver and gonads may suggest that Hg bioaccumulation in these fish shows adverse physiological effects. Though HQ values in both species were below the unit, i.e., the consumption of the muscle from this species does not represent a health risk, it is necessary to carry out surveys of fish consumption rates in coastal areas of Mexico to do a more precise health risk assessment associated to Hg intake.


Assuntos
Mercúrio , Poluentes Químicos da Água , Animais , Bioacumulação , California , Monitoramento Ambiental , Mercúrio/análise , México , Medição de Risco , Poluentes Químicos da Água/análise
15.
Environ Monit Assess ; 192(11): 705, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33063182

RESUMO

The present study aimed at evaluating the levels of microbiological contamination, total petroleum hydrocarbons (TPHs), and heavy metals (As, Cd, Hg, and Pb) in the edible tissues of commonly consumed fish (8 species) collected from the marine area of Tripoli, Northern Lebanon. Total coliform levels in all sampled fish, and Escherichia coli levels in Liza ramada only, exceeded the permissible limits set by FAO/WHO 2002. Staphylococcus aureus counts were within the recommended thresholds, while sulfate-reducing bacteria levels were the highest in fish of the genus Liza. Salmonella species and Listeria monocytogenes were not detected in all fish analyzed. Analysis of heavy metals levels showed that arsenic exhibited the highest levels among the assessed metals in all genera. Levels of As in Epinephelus, Diplodus, Oblada, and Liza were above the acceptable limits, while Cd levels were below the permissible limits set by the European Commission. Significant negative correlation was found between levels of As and Hg in muscle tissues and fish size (length). Levels of TPHs were the highest in fish of the genus Epinephelus. Significant difference in TPHs contamination was found within three fish genera, with Epinephelus being the most contaminated.


Assuntos
Metais Pesados , Petróleo , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Contaminação de Alimentos/análise , Hidrocarbonetos , Líbano , Metais Pesados/análise , Poluentes Químicos da Água/análise
16.
Ecotoxicol Environ Saf ; 203: 110994, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888603

RESUMO

The effects of cyanobacteria (Aphanizomenon flos-aquae (90%), Microcystis aeruginosa) and dense Elodea canadensis beds on the health endpoints of the amphipod Gmelinoides fasciatus and bivalve mollusc Unio pictorum were examined in mesocosms with simulated summer conditions (July-August 2018) in the environment of the Rybinsk Reservoir (Volga River Basin, Russia). Four treatments were conducted, including one control and three treatments with influencing factors, cyanobacteria and dense elodea beds (separately and combined). After 20 days of exposure, we evaluated the frequency of malformed and dead embryos in amphipods, heart rate (HR) and its recovery (HRR) after stress tests in molluscs as well as heat tolerance (critical thermal maximum or CTMax) in both amphipods and molluscs. The significant effect, such as elevated number of malformed embryos, was recorded after exposure with cyanobacteria (separately and combined with elodea) and presence of microcystins (MC) in water (0.17 µg/l, 40% of the most toxic MC-LR contribution). This study provided evidence that an elevated number (>5% of the total number per female) of malformed embryos in amphipods showed noticeable toxicity effects in the presence of cyanobacteria. The decreased oxygen under the influence of dense elodea beds led to a decrease in HR (and an increase in HRR) in molluscs. The notable effects on all studied biomarkers, embryo malformation frequency and heat tolerance in the amphipod G. fasciatus, as well as the heat tolerance and heart rate in the mollusc U. pictorum, were found when both factors (elodea and cyanobacteria) were combined. The applied endpoints could be further developed for environmental monitoring, but the obtained results support the importance of the combined use of several biomarkers and species, especially in the case of multi-factor environmental stress.


Assuntos
Anfípodes/efeitos dos fármacos , Bivalves/efeitos dos fármacos , Cianobactérias/metabolismo , Monitoramento Ambiental/métodos , Hydrocharitaceae/metabolismo , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Aphanizomenon/metabolismo , Biomarcadores/análise , Bivalves/metabolismo , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Microcistinas/metabolismo , Microcistinas/toxicidade , Microcystis/metabolismo , Federação Russa , Poluentes Químicos da Água/metabolismo
17.
Ecotoxicol Environ Saf ; 203: 110957, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888620

RESUMO

Due to growing commercial interest as a fishing resource and its intermediate position in the marine trophic chains as both prey and predator, cephalopods can play an important role in mercury (Hg) transfer along the marine food webs, since they can bioaccumulate this metal in its tissues. Our study aims to analyze Hg accumulation in Loligo forbesi caught in the Azores Archipelago (Portugal) quantifying Hg in different tissues (mantle and stomach), as well in the squid stomach content, in order to evaluate the efficiency of Hg transfer from prey to predator. Hg data from the tissues was used to estimate the weekly tolerable Hg intake due to squid consumption. Overall data indicate that Hg measured in the stomach tissue (0.1 ± 0.01 µg g-1) was significantly higher than Hg levels found in the mantle (0.04 ± 0.001 µg g-1) and stomach contents (0.01 ± 0.001 µg g-1). BMF (bioaccumulation factor) was >1 for all the samples, indicating a biomagnification process from prey to predator. Hg concentration in the mantle tissue was correlated with mantle size; although females present higher Hg levels than males, the difference was found to be not related to gender but rather to the fact that females had larger bodies. Finally, considering the Hg concentration found in the mantle and the permitted Hg levels, it is advisable to consume up to 1050-1890g of squid per week, according to the regulatory agencies. Thus, our results indicate that, since these doses are respected, consumption of squids from the Azorean waters do not pose a risk to humans.


Assuntos
Bioacumulação , Exposição Dietética/análise , Monitoramento Ambiental/métodos , Loligo/metabolismo , Mercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Feminino , Cadeia Alimentar , Humanos , Masculino , Mercúrio/análise , Portugal , Alimentos Marinhos/análise , Poluentes Químicos da Água/análise
18.
Water Sci Technol ; 82(4): 640-650, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32970617

RESUMO

Micropollutants such as endocrine disruptors are one of the most important groups of chemicals polluting water resources. Conventional treatment systems may not be effective for the removal of endocrine disrupting chemicals (EDCs), and the fate of these chemicals should be carefully monitored in the effluent of wastewater treatment plants (WWTPs). Additional treatment methods such as advanced oxidation processes can be used for the removal of endocrine disruptors. This study presents the existence of endocrine disruptors in 4 different effluents: (i) municipal WWTP effluent, (ii) textile industry WWTP effluent, (iii) organized industrial zone (OIZ) WWTP effluent and (iv) pharmaceutical industry discharge and also presents their removal efficiencies by ozonation and peroxone oxidation. A broad spectrum of removal efficiencies was observed for the EDCs present in the samples since the oxidation efficiency of wastewaters containing EDCs mainly depends on the wastewater matrix and on the type of the EDCs. Ozonation was found to be a lower-cost option than peroxone oxidation at the investigated conditions.


Assuntos
Disruptores Endócrinos/análise , Ozônio , Poluentes Químicos da Água/análise , Eliminação de Resíduos Líquidos , Águas Residuárias
19.
Water Sci Technol ; 82(4): 673-682, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32970620

RESUMO

Loess is a typical natural mineral particle distributed widely around the world, and it is inexpensive, readily accessible, and harmless to the environment. In this study, loess was modified by surface grafting copolymerization of functional monomers, such as acrylic acid, N-vinyl pyrrolidone, and N,N-methylenebisacrylamide as a cross-linking agent, which afforded a novel loess-based grafting copolymer (LC-PAVP). After being characterized by scanning electron microscopy, thermal gravimetric analysis and Fourier-transform infrared spectroscopy, its adsorption capacity and mechanism of removing lead ions (Pb2+) were investigated. With the study of the optimal experimental conditions, it was demonstrated that the removal rate of Pb2+ by LC-PAVP can reach up to 99.49% in 60 min at room temperature. It was also found that the kinetic characteristics of the adsorption capacity due to the pseudo-second-order kinetic model and the thermodynamics conformed well with the Freundlich model. In summary, as a lost-cost and eco-friendly loess-based adsorbent, LC-PAVP is a good potential material for wastewater treatment.


Assuntos
Acrilatos , Poluentes Químicos da Água/análise , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Polímeros , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Águas Residuárias
20.
Water Sci Technol ; 82(4): 695-703, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32970622

RESUMO

The current work investigates the removal of two hazardous macrolide molecules, spiramycin and tylosin, by photodegradation under external UV-light irradiation conditions in a slurry photoreactor using titanium dioxide as a catalyst. The kinetics of degradation and effects of main process parameters such as catalyst dosage, initial macrolide concentration, light intensity and stirring rate on the degradation rate of pollutants have been examined in detail in order to obtain the optimum operational conditions. It was found that the process followed a pseudo first-order kinetics according to the Langmuir-Hinshelwood model. The optimum conditions for the degradation of spiramycin and tylosin were low compound concentration, 1 g L-1 of catalyst dosage, 100 W m-2 light intensity and 560 rpm stirring rate. Then, a maximum removal (more than 90%) was obtained after 300 min of irradiation time. Furthermore, results show that the selection of optimized operational parameters leads to satisfactory total organic carbon removal rate (up to 51%) and biochemical oxygen demand to chemical oxygen demand ratio (∼1) confirming the good potential of this technique to remove complex macrolides from aqueous solutions.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Catálise , Cinética , Macrolídeos , Fotólise , Titânio , Raios Ultravioleta
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