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1.
PLoS One ; 15(6): e0228524, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497041

RESUMO

Nester abundance is a key measure of the performance of the world's largest green turtle rookery at Raine Island, Australia, and has been estimated by mark-resight counts since 1984. Nesters are first marked by painting their carapace with a longitudinal white stripe. Painted and unpainted turtles are then counted by a surface observer on a small boat in waters adjacent to the reef. Unmanned aerial vehicles (UAV) and underwater video may provide more cost-effective and less biased alternatives to this approach, but estimates must be comparable with historical estimates. Here we compare and evaluate the three methods. We found comparatively little variation in resighting probabilities between consecutive days of sampling or time of day, which supports an underlying assumption of the method (i.e. demographic closure during sampling). This lack of bias in the location availability for detection of painted versus unpainted turtles and further supported by a parallel satellite tracking study of 40 turtles at Raine Island. Our results demonstrated that surface observers consistently reported higher proportions of marked turtles than either the UAV or underwater video method. This in turn yielded higher population estimates with UAV or underwater video compared to the historical surface observer method, which suggested correction factors of 1.53 and 1.73 respectively. We attributed this to observer search error because a white marked turtle is easier to spot than the non-marked turtle. In contrast, the UAV and underwater video methods allowed subsequent frame-by-frame review, thus reducing observer search error. UAVs were the most efficient in terms of survey time, personnel commitment and weather tolerance compared to the other methods. However, underwater video may also be a useful alternative for in-water mark-resight surveys of turtles.


Assuntos
Monitoramento Ambiental/instrumentação , Ilhas , Comportamento de Nidação , Tartarugas , Animais , Automação , Feminino , Imersão , Densidade Demográfica , Queensland , Gravação em Vídeo
2.
Biosens Bioelectron ; 165: 112349, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32510340

RESUMO

Timely detection and diagnosis are urgently needed to guide epidemiological measures, infection control, antiviral treatment, and vaccine research. In this review, biomarkers/indicators for diagnosis of coronavirus disease 2019 (COVID-19) or detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the environment are summarized and discussed. It is concluded that the detection methods targeting antibodies are not suitable for screening of early and asymptomatic cases since most patients had an antibody response at about 10 days after onset of symptoms. However, antibody detection methods can be combined with quantitative real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) to significantly improve the sensitivity and specificity of diagnosis, and boost vaccine research. Fast, sensitive and accurate detection methods targeting antigens need to be developed urgently. Various specimens for diagnosis or detection are compared and analyzed. Among them, deep throat saliva and induced sputum are desired for RT-qPCR test or other early detection technologies. Chest computerized tomography (CT) scan, RT-qPCR, lateral flow immunochromatographic strip (LFICS) for diagnosis of COVID-19 are summarized and compared. Specially, potential electrochemical (EC) biosensor, surface enhanced Raman scattering (SERS)-based biosensor, field-effect transistor (FET)-based biosensor, surface plasmon resonance (SPR)-based biosensor and artificial intelligence (AI) assisted diagnosis of COVID-19 are emphasized. Finally, some commercialized portable detection device, current challenges and future directions are discussed.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Animais , Anticorpos Antivirais/análise , Antígenos Virais/análise , Técnicas Biossensoriais/métodos , Cromatografia de Afinidade/instrumentação , Cromatografia de Afinidade/métodos , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Desenho de Equipamento , Humanos , Pandemias , Reação em Cadeia da Polimerase/instrumentação , Reação em Cadeia da Polimerase/métodos , RNA Viral/análise , Fitas Reagentes/análise , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos
3.
J Environ Sci Health B ; 55(8): 694-703, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32536292

RESUMO

Organochlorine pesticides (OCPs) were analyzed in three different ages (half-, 1.5-, 2.5-year-old) for needles and semi permeable membrane devices (SPMDs) at three deployment periods from sea level to 1881 meter above sea level. Individual HCHs concentrations ranged between 1.4 and 129 pg/g fw depending on the age and sampling season while 2.5-year-old needles showed higher HCHs levels compared to half and 1.5- year-old. Correlation between elevation and HCH concentration in SPMDs was found but not in needle samples. Concentrations of HCHs in SPMDs indicated clearly cold condensation effect on accumulation in winter period and increased with altitude. Concentrations of DDTs in half and 1.5-year-old needles were lower than 2.5-year-old needles. The highest total concentration of DDTs was detected in 1-year-period SPMD. Higher concentrations were found in 2.5-year-old needles for other OCPs. Seasonal and altitude-dependent changes were not observed for other OCPs in SMPDs. Total accumulation of OCPs in SPMDs were found higher than in needles. On the contrary, an increased accumulation rate was observed for HCHs in SPMD. In general, Total concentrations of DDTs and HCHs were similar to total of other OCPs in all altitudes when dominating endosulfan wasnot taken into account in the computation of total concentration of other OCPs.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/instrumentação , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Altitude , Monitoramento Ambiental/métodos , Pinus/química , Estações do Ano , Turquia
4.
J Vis Exp ; (159)2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32510496

RESUMO

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future combustion engine vehicle technology may emit large amounts of sub-23 nm particles. The Horizon 2020 funded project DownToTen (DTT) developed a sampling and measurement method to characterize particle emissions in this currently unregulated size range. A PN measurement system was developed based on an extensive review of the literature and laboratory experiments testing a variety of PN measurement and sampling approaches. The measurement system developed is characterized by high particle penetration and versatility, which enables the assessment of primary particles, delayed primary particles, and secondary aerosols, starting from a few nanometers in diameter. This paper provides instruction on how to install and operate this Portable Emission Measurement System (PEMS) for Real Drive Emissions (RDE) measurements and assess particle number emissions below the current legislative limit of 23 nm.


Assuntos
Condução de Veículo , Monitoramento Ambiental/métodos , Nanopartículas/análise , Nanopartículas/química , Tamanho da Partícula , Emissões de Veículos/análise , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental/instrumentação , Laboratórios , Material Particulado/análise , Material Particulado/química
5.
Ecotoxicol Environ Saf ; 200: 110771, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32464443

RESUMO

Herein is presented a simple and sensible method to determine organic pollutants in water, based on the utilization of silver nanoparticles (AgNPs) loaded in Polyacrylamide (PAAm)/starch hybrid hydrogels combined with surface-enhanced Raman scattering (SERS) spectroscopy. The materials were characterized by swelling degree studies, UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and scanning electron microscopy (SEM). PAAm/starch hydrogels showed variable swelling capacity, according to the synthetic molar composition. The most promising results were attributed to lower concentrations of starch and crosslink agent (N,N'-methylenebisacrylamide - MBA). Spectroscopic analysis confirmed the formation of AgNPs, by noticing the peak at around 420 nm, due to its surface plasmon resonance (SPR) effect. The results showed that AgNPs were stabilized by hydrogels networks. The average size of the AgNPs was smaller than 100 nm and the size and quantity of nanoparticles were influenced by the molar composition of the hydrogel matrix. The SERS substrate based on the AgNPs-PAAm/starch exhibited reproducibility, stability, and limit of detection (LOD) of phenol in water of 1 × 10-8 M. The average mass of AgNPs-PAAm/starch hydrogels used for each detection analysis was around 10 mg. The spectra with enhanced intensities were possible due to a large number of hot spots generated on the AgNPs-PAAm/starch hydrogel substrate, which leads to potential use for organic pollutant detection. In addition, there is also the possibility of reusing the hydrogel matrix substrate in other analyzes.


Assuntos
Monitoramento Ambiental/métodos , Hidrogéis/química , Nanopartículas Metálicas/química , Fenóis/análise , Prata/química , Poluentes Químicos da Água/análise , Resinas Acrílicas/química , Monitoramento Ambiental/instrumentação , Limite de Detecção , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Análise Espectral Raman , Amido/química , Ressonância de Plasmônio de Superfície , Água , Difração de Raios X
6.
Chemosphere ; 255: 126964, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416391

RESUMO

A water quality early-warning instrument for evaluating acute water toxicity based on the electrochemical biosensor, Model ETOX18-01, was developed and manufactured with the features of low current detection (0.1 nA), precise thermostatic control, self-cleaning as well as remote data transmission. A sensitive integrated microbial electrode, made up of a glass carbon electrode that was modified by an active biofilm consisting of Escherichia coli, thionine, carbon nanodots and chitosan, has been fabricated as the biosensor. To validate the performance, multiple real water samples and artificial water samples were tested by Model ETOX18-01, and compared with ISO standardized luminescent bacterial test simultaneously. The correlation between the Model ETOX18-01 and luminescent bacterial test for these water samples showed good determination coefficient (R2 = 0.9827). In addition, Model ETOX18-01 is more sensitive to colored metal ionic samples. With its characteristics of high sensitivity, excellent repeatability and easy operation, the instrument Model ETOX18-01 provides a promising tool for large-scale water environmental assessment, and has a potential application in evaluating the water quality and early risk warning.


Assuntos
Técnicas Biossensoriais/instrumentação , Monitoramento Ambiental/instrumentação , Poluentes Químicos da Água/análise , Carbono , Quitosana/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Monitoramento Ambiental/métodos , Íons , Fenotiazinas , Água , Poluentes Químicos da Água/toxicidade
7.
PLoS One ; 15(5): e0232331, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32369524

RESUMO

A floating power generation device is designed and fabricated to overcome the power supply limitations of wireless sensor networks for environmental monitoring. Once there is a temperature difference between the upper surface exposed to sunlight and the lower surface in the water, the device is capable of generating power while floating in the wetland environment. Fresnel lenses were applied to concentrate solar irradiation on a selective absorbing coat. Meanwhile two vertical axis rotors were used to cool the cold side of the thermoelectric power generator by catching the breeze. The effects of solar irradiation, temperature distribution, load resistance, wind speed, the maximum power and the electrical efficiency of the thermoelectric power generator were analyzed. When subjected to solar irradiation of 896.38 W/m2, the device generated a potential difference of 381.03 mV and a power output of 8.86 mW via thermoelectric generation. In addition, compared with the system without wind, the output power was increased by approximately 10.96% in our system. The low power wireless networks, used in wetland environments, could be operated by the thermoelectric power generated by the floating device. Besides, this system offers powering solution for self-power miniature devices that are applied in aqueous environment.


Assuntos
Fontes de Energia Elétrica , Monitoramento Ambiental/instrumentação , Energia Renovável , Áreas Alagadas , Tecnologia sem Fio/instrumentação , Desenho de Equipamento , Modelos Teóricos , Luz Solar , Temperatura , Água , Vento
8.
Environ Monit Assess ; 192(5): 275, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32270289

RESUMO

In this study, a switchable solvent-based liquid-phase microextraction method was developed to preconcentrate selected pesticides from tap water and wastewater matrices for determination by gas chromatography-mass spectrometry. A thorough optimization process was performed for prominent extraction parameters such as switchable solvent amount, concentration/amount of sodium hydroxide, salt type and mixing period. Optimum parameters obtained at the end of the optimization process were applied to aqueous standard solutions to validate the method. The linear dynamic ranges of all four analytes were appreciably wide with coefficient of determination values greater than 0.9997. The limits of detection and quantification (LOD and LOQ) were calculated for the analytes in the ranges of 0.38-2.0 ng/mL and 1.3-6.5 ng/mL, respectively. Spiked recovery experiments were used to validate the accuracy of the developed method and to determine the performance of the method in different sample matrices. Tap water, municipal wastewater and medical wastewater were spiked at three different concentrations and analyzed under the method's optimum conditions. The percent recovery results calculated for the samples were in the range of 79-107%, and this validated the method's accuracy and applicability to complex matrices such as municipal and medical wastewater samples.


Assuntos
Monitoramento Ambiental , Herbicidas , Inseticidas , Microextração em Fase Líquida , Poluentes Químicos da Água , Monitoramento Ambiental/instrumentação , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Solventes , Águas Residuárias
9.
J Chromatogr A ; 1619: 460947, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32268954

RESUMO

A simple, portable and battery-powered trapping device (iTrap) consisting of a purification tube, a trapping unit and a miniature air pump was developed for the pre-concentration of volatile organic sulfur compounds (VOSCs). The tested VOSCs, including methanthiol (MT), ethanethiol (ET), dimethyl sulfide (DMS), diethyl sulfide (DES) and dimethyl disulfide (DMDS), were firstly purged from water samples and then in situ pre-concentrated with the iTrap prior to their analysis by thermal desorption gas chromatography coupling with a sulfur chemiluminescence detector (TD-GC-SCD). Twenty-six adsorbents were studied to find the most suitable adsorbent for the efficient pre-concentration of VOSCs. Under optimal conditions, limits of detection of 6, 8, 6, 2 and 3 ng L-1 were obtained for MT, ET, DMS, DES and DMDS, respectively. The precisions were better than 5.3% (relative standard deviations, RSDs). The iTrap was successfully applied for the analysis of VOSCs in Certified Reference Materials, several surface water, underground water and wastewater samples collected from Pengzhou city, Sichuan, China. Moreover, the VOSCs trapped in the iTrap were much more stable than those directly stored in water samples and the recoveries for all samples could be maintained at acceptable levels (>73%), even their preservation time as long as 8 h.


Assuntos
Cromatografia Gasosa , Monitoramento Ambiental/métodos , Compostos de Enxofre/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificação , Águas Residuárias/química , China , Monitoramento Ambiental/instrumentação , Luminescência , Compostos de Enxofre/análise , Compostos Orgânicos Voláteis/análise
10.
Environ Monit Assess ; 192(5): 311, 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32328808

RESUMO

Remote sensing data from Indian geostationary satellites (Kalapana-1, INSAT 3A) were used for the first time for early warning of agricultural drought and forewarning of crop vigour. An Early warning indicator (EWI) was developed from operational product of rainfall and reference evapotranspiration from observations of Kalpana-1 very high resolution radiometer (VHRR). The effectiveness of EWI was evaluated for the two drought years (2009 and 2012). The positive correlation (r = 0.66-0.68 for 2009 and r = 0.64-0.70 for 2012) between the EWI in the month of June-July and standardized precipitation index-1 (SPI-1) averaged over administrative unit (called district) indicates that EWI can be used successfully for drought early warning. Lag-response behaviour between EWI and crop vigour in terms of normalized difference vegetation index (NDVI) and LAI (leaf area index) over cropland was studied. Systematic patterns emerged for 30 days lag period between negative EWI and NDVI at both grid-scale (0.25°) and at district level. Linear relations were found between 10-day EWI and NDVI or LAI at 30 days lag during June-July period. Linear models were developed to forewarn crop vigour which was validated with realized NDVI from INSAT 3A charge-coupled device (CCD) observations within 95% accuracy. The EWI is recommended as potential indicator for early-season agricultural drought assessment and can be used for sub-district scale with finer scale rainfall and evaporation products from advanced next-generation geostationary meteorological satellites.


Assuntos
Agricultura , Secas , Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , Agricultura/métodos , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Índia , Meteorologia/instrumentação , Comunicações Via Satélite
11.
Environ Monit Assess ; 192(5): 307, 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32328814

RESUMO

Conventional water quality measurements are nearly impossible during and immediately after extreme storms due to dangerous conditions. In this study, remotely sensed reflectance is used to develop a regression equation that quantifies total suspended solids (TSS) in near real-time after Hurricane Harvey. The application focused specifically on sediment loading and deposition and its potential impacts on the Houston Ship Channel and Galveston Bay riverine-estuarine system. The European Space Agency's Sentinel-2 satellite captured images at critical points in the storm's progression, necessitating the development of a new algorithm for this relatively new satellite mission. Several linear regressions were analyzed with the goal of developing a simple one- or two-band equation, and the final model uses the red and near infrared bands (R2 = 0.74). Results show that record flows during Harvey delivered unprecedented suspended sediment loads to the Gulf of Mexico at concentrations above 125 mg/L with a mean concentration of 43 mg/L across the bay. The study findings demonstrated that it took up to 11 days after the storm for sediment transport to abate.


Assuntos
Tempestades Ciclônicas , Monitoramento Ambiental , Clima Extremo , Modelos Teóricos , Qualidade da Água , Água , Monitoramento Ambiental/instrumentação , Sedimentos Geológicos/química , Golfo do México , Tecnologia de Sensoriamento Remoto , Comunicações Via Satélite , Análise Espectral , Texas , Água/química
12.
Chemosphere ; 250: 126284, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32234620

RESUMO

Semi-volatile organic compounds (SVOCs), such as phthalates, organophosphates, and polybrominated diphenyl ethers, are emerging as an important class of pollutants that are of serious health concerns. Determining concentrations of these pollutants is of great importance for environmental and exposure studies. In this work, a needle trap device (NTD) method was developed to measure the concentration of SVOCs in air samples. Sorbents were packed in the NTD to capture SVOCs with the aid of a sampling pump. NTD operational parameters, such as desorption temperature, desorption time, and sampling flow rate, were optimized for the target SVOCs. The limit of detection for air sampling by the NTD method ranged between 5 pg and 1 ng, depending on the SVOC compound. The variations in terms of NTD repeatability and reproducibility were lower than 14% for all cases. In addition, the influence of other experimental parameters, such as sampling temperature and humidity, breakthrough volume, NTD storage time, as well as carryover effect were examined. Finally, NTDs were used to determine emissions of gas-phase SVOCs from various consumer products in an emission cell and to collect total airborne SVOC samples (gas and particle phases) in an office. The results of NTD method were in an agreement with data obtained by conventional active sampling methods using Tenax® sorbent tubes and polyurethane foam samplers, but with improvements of relative standard deviation, sensitivity, and sampling time. The results demonstrated that the NTD method is a simple, sensitive, effective, reusable, and inexpensive technique for sampling and analyzing SVOCs in the concentration range from 2 ng m-3 to 100 µg m-3 in air.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Agulhas , Compostos Orgânicos Voláteis/análise , Alcanos/análise , Monitoramento Ambiental/instrumentação , Desenho de Equipamento , Éteres Difenil Halogenados/análise , Ácidos Ftálicos/análise , Temperatura
13.
PLoS Biol ; 18(4): e3000655, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32240158

RESUMO

Recent advances in animal tracking technology have ushered in a new era in biologging. However, the considerable size of many sophisticated biologging devices restricts their application to larger animals, whereas older techniques often still represent the state-of-the-art for studying small vertebrates. In industrial applications, low-power wireless sensor networks (WSNs) fulfill requirements similar to those needed to monitor animal behavior at high resolution and at low tag mass. We developed a wireless biologging network (WBN), which enables simultaneous direct proximity sensing, high-resolution tracking, and long-range remote data download at tag masses of 1 to 2 g. Deployments to study wild bats created social networks and flight trajectories of unprecedented quality. Our developments highlight the vast capabilities of WBNs and their potential to close an important gap in biologging: fully automated tracking and proximity sensing of small animals, even in closed habitats, at high spatial and temporal resolution.


Assuntos
Quirópteros , Monitoramento Ambiental/métodos , Tecnologia de Sensoriamento Remoto/métodos , Tecnologia sem Fio , Animais , Comportamento Animal , Quirópteros/fisiologia , Ecossistema , Fontes de Energia Elétrica , Monitoramento Ambiental/instrumentação , Feminino , Alemanha , Masculino , Panamá , Comportamento Social , Análise Espaço-Temporal , Clima Tropical , Vertebrados
14.
PLoS One ; 15(4): e0231778, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32330173

RESUMO

Air pollution with PM2.5 (particulate matter smaller than 2.5 micro-metres in diameter) is a major health hazard in many cities worldwide, but since measuring instruments have traditionally been expensive, monitoring sites are rare and generally show only background concentrations. With the advent of low-cost, wirelessly connected sensors, air quality measurements are increasingly being made in places where many people spend time and pollution is much worse: on streets near traffic. In the interests of enabling members of the public to measure the air that they breathe, we took an open-source approach to designing a device for measuring PM2.5. Parts are relatively cheap, but of good quality and can be easily found in electronics or hardware stores, or on-line. Software is open source and the free LoRaWAN-based "The Things Network" the platform. A number of low-cost sensors we tested had problems, but those selected performed well when co-located with reference-quality instruments. A network of the devices was deployed in an urban centre, yielding valuable data for an extended time. Concentrations of PM2.5 at street level were often ten times worse than at air quality stations. The devices and network offer the opportunity for measurements in locations that concern the public.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Participação da Comunidade , Monitoramento Ambiental/instrumentação , Material Particulado/análise , Poluição do Ar/efeitos adversos , Cidades , Monitoramento Ambiental/métodos , Humanos , Limite de Detecção , New South Wales , Material Particulado/efeitos adversos , Emissões de Veículos/análise , Incêndios Florestais
15.
Bull Environ Contam Toxicol ; 104(4): 464-470, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32215685

RESUMO

This work reports on the method optimization and application for quantitative analysis of non-steroidal anti-inflammatory drugs and anti-epileptic drug in soil and sediment samples. The analytes were extracted by ultrasonic extraction followed by solid phase extraction and quantified using liquid chromatographic coupled with photodiode array. The sensitivity of the method was determined based on the limit of detection and the limit of quantification which ranged between (0.010-0.027 µg/kg) and (0.025-0.049 µg/kg), respectively. The %recoveries of the method ranged between 74% and 112%. The concentrations obtained in real samples ranged from 0.055 to 0.426 µg/kg in sediment and 0.044-0.567 µg/kg in soil samples. The highest concentration was found for diclofenac in soil samples.


Assuntos
Anti-Inflamatórios não Esteroides/análise , Anticonvulsivantes/análise , Monitoramento Ambiental , Poluentes Ambientais/análise , Sedimentos Geológicos/química , Solo/química , Ondas Ultrassônicas , Cromatografia Líquida de Alta Pressão/métodos , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Limite de Detecção , Extração em Fase Sólida/métodos
16.
Chemosphere ; 249: 126183, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32088466

RESUMO

Diffusion coefficient (D) is an important parameter for prediction of micropollutant uptake kinetics in passive samplers. Passive samplers are nowadays commonly used for monitoring trace organic pollutants in different environmental matrices. Samplers utilising a hydrogel layer to control compound diffusion are gaining popularity. In this work we investigated diffusion of several perfluoroalkyl substances, currently used pesticides, pharmaceuticals and personal care products in 1.5% agarose hydrogel by measuring diffusion coefficients using two methods: a diffusion cell and a sheet stacking technique. Further, diffusion coefficients in water were measured using Taylor dispersion method. The sheet stacking method was used to measure D at 5, 12, 24, and 33 °C in order to investigate temperature effect on diffusion. Median D values ranged from 2.0 to 8.6 × 10-6 cm2 s-1 and from 2.1 to 8.5 × 10-6 cm2 s-1 for the diffusion cell and sheet stack methods respectively. For most compounds, the variability between replicates was higher than the difference between values obtained by the two methods. Rising temperature from 10 to 20 °C increases the diffusion rate by the factor of 1.41 ± 0.10 in average. In water, average D values ranged from 3.03 to 10.0 × 10-6 cm2 s-1 and were comparable to values in hydrogel, but some compounds including perfluoroalkyl substances with a long aliphatic chain could not be evaluated properly due to sorptive interactions with capillary walls in the Taylor dispersion method. Sampling rates estimated using the measured D values were systematically higher than values estimated from laboratory sampler calibration in our previously published study, by the factor of 2.2 ± 1.0 in average.


Assuntos
Monitoramento Ambiental/métodos , Sefarose/análise , Poluentes Químicos da Água/análise , Transporte Biológico , Cosméticos , Difusão , Monitoramento Ambiental/instrumentação , Hidrogéis , Cinética , Compostos Orgânicos , Praguicidas/análise , Temperatura , Água
17.
Chemosphere ; 248: 126070, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32028165

RESUMO

Urban runoff conveys contaminants including titanium dioxide (TiO2), widely used as engineered nanoparticles (e.g., 1-100 nm) and pigments (e.g., 100-300 nm) in the urban environment, to receiving surface waters. Yet, the concentrations of TiO2 engineered particles (e.g., engineered nanoparticles and pigments) in urban runoff has not been determined due to difficulties in distinguishing natural from engineered TiO2 particles in environmental matrices. The present study examines the occurrence and estimates the concentrations of TiO2 engineered particles in urban runoff under wet- and dry-weather conditions. Urban runoff was collected from two bridges in Columbia, South Carolina, USA under wet-weather conditions and from the Ballona Creek and Los Angeles (LA) River in Los Angeles, California, USA under dry-weather conditions. The concentrations of TiO2 engineered particles were determined by mass balance calculations based on shifts in elemental concentration ratios in urban runoff relative to natural background elemental ratios. Elemental ratios of Ti to Nb in urban runoff were higher than the natural background ratios, indicating Ti contamination. The occurrence of TiO2 engineered particles was further confirmed by transmission electron microscopy coupled with energy dispersive spectroscopy. The concentration of TiO2 engineered particles in urban runoff was estimated to be in the range of 5-150 µg L-1. Therefore, this study identifies urban runoff as a previously unaccounted source of TiO2 engineered particle release to the environment, which should be included in engineered nanoparticle fate modeling studies and in estimating environmental release of engineered nanoparticles.


Assuntos
Monitoramento Ambiental/métodos , Nanopartículas/análise , Rios/química , Titânio/análise , Poluentes Químicos da Água/análise , California , Cidades , Monitoramento Ambiental/instrumentação , South Carolina , Tempo (Meteorologia)
19.
Environ Monit Assess ; 192(3): 171, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32040639

RESUMO

Integration of low-cost air quality sensors with the internet of things (IoT) has become a feasible approach towards the development of smart cities. Several studies have assessed the performance of low-cost air quality sensors by comparing their measurements with reference instruments. We examined the performance of a low-cost IoT particulate matter (PM10 and PM2.5) sensor in the urban environment of Santiago, Chile. The prototype was assembled from a PM10-PM2.5 sensor (SDS011), a temperature and relative humidity sensor (BME280) and an IoT board (ESP8266/Node MCU). Field tests were conducted at three regulatory monitoring stations during the 2018 austral winter and spring seasons. The sensors at each site were operated in parallel with continuous reference air quality monitors (BAM 1020 and TEOM 1400) and a filter-based sampler (Partisol 2000i). Variability between sensor units (n = 7) and the correlation between the sensor and reference instruments were examined. Moderate inter-unit variability was observed between sensors for PM2.5 (normalized root-mean-square error 9-24%) and PM10 (10-37%). The correlations between the 1-h average concentrations reported by the sensors and continuous monitors were higher for PM2.5 (R2 0.47-0.86) than PM10 (0.24-0.56). The correlations (R2) between the 24-h PM2.5 averages from the sensors and reference instruments were 0.63-0.87 for continuous monitoring and 0.69-0.93 for filter-based samplers. Correlation analysis revealed that sensors tended to overestimate PM concentrations in high relative humidity (RH > 75%) and underestimate when RH was below 50%. Overall, the prototype evaluated exhibited adequate performance and may be potentially suitable for monitoring daily PM2.5 averages after correcting for RH.


Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Material Particulado , Animais , Chile , Cidades , Monitoramento Ambiental/economia , Monitoramento Ambiental/instrumentação , Estações do Ano
20.
Artigo em Inglês | MEDLINE | ID: mdl-32053927

RESUMO

The aim of this pilot study was to assess whether the installation of ultraviolet radiation (UVR) meters in secondary schools has the potential to improve adolescents' sun protection-related knowledge, attitudes, and behaviours and reduce their exposure to UVR during school hours. Data were collected from students at two schools via online pre- and post-intervention surveys, measurement of sunscreen usage, polysulfone UVR exposure badges, and photographs of the schoolyards to assess hat and shade use. Several operational issues limited the quantity and quality of data that could be collected, and findings were mixed. While there were no significant changes in either self-reported or observed sun protection behaviours, there were significant improvements in UVR knowledge among students at the intervention school, and reactions to the meter were highly favourable. Students reported consulting the meter regularly and using it to make decisions about their sun protection behaviours. Overall, the study results offer some support for the use of UVR meters in areas frequented by adolescents and provide insights into the process issues that are likely to need to be addressed when attempting to trial sun protection interventions in schools.


Assuntos
Instituições Acadêmicas , Neoplasias Cutâneas , Queimadura Solar , Raios Ultravioleta , Adolescente , Monitoramento Ambiental/instrumentação , Humanos , Projetos Piloto , Neoplasias Cutâneas/prevenção & controle , Protetores Solares , Raios Ultravioleta/efeitos adversos
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