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1.
Molecules ; 26(11)2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34198752

RESUMO

In recent years, many studies have reported the frequent detection of antihypertensive agents such as sartans (olmesartan, valsartan, irbesartan and candesartan) in the influents and effluents of wastewater treatment plants (WWTPs) and in the superficial waters of rivers and lakes in both Europe and North America. In this paper, the degradation pathway for candesartan (CAN) was investigated by simulating the chlorination process that is normally used to reduce microbial contamination in a WWTP. Twelve isolated degradation byproducts (DPs), four of which were isolated for the first time, were separated on a C-18 column by employing a gradient HPLC method, and their structures were identified by combining nuclear magnetic resonance and mass spectrometry and comparing the results with commercial standards. On the basis of these results, a mechanism of formation starting from the parent drug is proposed. The ecotoxicity of CAN and its DPs was studied by conducting a battery of ecotoxicity tests; bioassays were performed using Aliivibrio fischeri (bacterium), Daphnia magna (planktonic crustacean) and Raphidocelis subcapitata (alga). The ecotoxicity results shed new light on the increased toxicity of DPs compared with the parent compound.


Assuntos
Benzimidazóis/análise , Compostos de Bifenilo/análise , Ácido Hipocloroso/química , Tetrazóis/análise , Poluentes Químicos da Água/análise , Aliivibrio fischeri/efeitos dos fármacos , Animais , Benzimidazóis/toxicidade , Compostos de Bifenilo/toxicidade , Clorofíceas/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Europa (Continente) , Lagos/química , América do Norte , Rios/química , Tetrazóis/toxicidade , Águas Residuárias/química , Poluentes Químicos da Água/toxicidade , Purificação da Água
2.
Molecules ; 26(11)2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34198808

RESUMO

Volatile methylsiloxanes (VMSs) constitute a group of compounds used in a great variety of products, particularly personal care products. Due to their massive use, they are continually discharged into wastewater treatment plants and are increasingly being detected in wastewater and in the environment at low concentrations. The aim of this work was to develop and validate a fast and reliable methodology to screen seven VMSs in water samples, by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography with flame ionization detection (GC-FID). The influence of several factors affecting the extraction efficiency was investigated using a design of experiments approach. The main factors were selected (fiber type, sample volume, ionic strength, extraction and desorption time, extraction and desorption temperature) and optimized, employing a central composite design. The optimal conditions were: 65 µm PDMS/Divinylbenzene fiber, 10 mL sample, 19.5% NaCl, 39 min extraction time, 10 min desorption time, and 33 °C and 240 °C as extraction and desorption temperature, respectively. The methodology was successfully validated, showing low detection limits (up to 24 ng/L), good precision (relative standard deviations below 15%), and accuracy ranging from 62% to 104% in wastewater, tap, and river water samples.


Assuntos
Siloxanas/análise , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Ionização de Chama , Água Doce/química , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Rios/química , Águas Residuárias/química
3.
J Chromatogr A ; 1651: 462133, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34087719

RESUMO

Aminoglycosides are mostly used as veterinary antibiotics. In France, their consumption accounts for about 10% of all prescribed animal medicine. Due to their high polarity nature (log Kow < -3), they require chromatographic separation by hydrophilic interaction liquid chromatography or ion-pairing chromatography. This study presents the development of an ion pairing liquid chromatography with alkanesulfonates coupled to tandem mass spectrometry for the analysis of 10 aminoglycosides (spectinomycin, streptomycin, dihydrostreptomycin, kanamycin, apramycin, gentamicin, neomycin and sisomicin) in wastewater samples. The novelty of this method lies in the addition of the ion paring salt directly and only into the sample vial and not in the mobile phase, lowering the amount of salt added and consequently reducing signal inhibition. The optimized method was validated and showed satisfactory resolution, performances suitable with the analysis of aminoglycosides in wastewater samples, with limits of quantifications less than 10 ng/mL for most of the compounds, low matrix effects, high accuracy (85%-115% recoveries) and reproducibility (2%-12%RSD). It was then applied successfully to raw and treated wastewater samples.


Assuntos
Aminoglicosídeos/análise , Espectrometria de Massas em Tandem/métodos , Águas Residuárias/análise , Adsorção , Animais , Antibacterianos/análise , Cromatografia Líquida , Resíduos de Drogas/análise , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Reprodutibilidade dos Testes , Rios/química , Solventes/química
4.
Nat Commun ; 12(1): 3700, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34140471

RESUMO

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent.


Assuntos
Biota , Ecossistema , Rios , Animais , Biodiversidade , Biomassa , Tamanho Corporal , Chironomidae/fisiologia , Clima , Ephemeroptera/fisiologia , Insetos/fisiologia , Folhas de Planta/química , Floresta Úmida , Rios/química , Rios/microbiologia , Rios/parasitologia , Rios/virologia , Clima Tropical , Tundra
5.
Ecotoxicol Environ Saf ; 220: 112360, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058680

RESUMO

Recently, emerging pollutants, such as anthelmintics have attracted an increasing attention worldwide due to their extensive use and notable stability. However, the information on anthelmintics in the environment of southwest China is scarce. Thus, the occurrence, ecological risk and exposure evaluation of nineteen anthelmintics in Tuojiang River, which is one of the largest tributaries of Yangtze River, and drinking water source of Sichuan, southwest China, were investigated. The result showed that the detection frequency of anthelmintics was relatively high in Tuojiang River, ranging from 65% to 100% in river water. Among the seven kinds of anthelmintics, benzimidazoles are the primary anthelmintics, with concentrations up to 61.12 ng/L and 596.06 ng/g in water and sediment of the Tuojiang river, respectively. The total concentration of 19 anthelmintics in sediment samples from non-agricultural area was higher than that in agricultural area(p = 0.000 < 0.05). This could be attributed to anthropogenic activities, which lead to greater discharge and accumulation of anthelmintics in residential area along the river. It's worth to mention that the highest total concentrations of anthelmintics (109.28 ng/L) was found at the junction of rivers in R31 site. The results could be ascribed to the complexity of junction of Tuojiang River and Yangtze River, which could influence the distribution of pollutant. Besides, the ecological risk assessment showed that the macrocyclic lactones rather than benzimidazoles had relatively high toxicity to non-target organisms in aquatic environment (p = 0.000 < 0.05), with the highest RQEcotox value of 101 for Daphnia magna, while benzimidazoles had relatively high concentrations. The exposure risk could be ignored for both children and adults because the daily intake of anthelmintics via water ingestion were below 10 ng/kg/d. In addition, strong correlations were found between sucralose and most of the selected anthelmintics in Tuojiang River, indicating that sucralose might be a good tracer to evaluated the source of anthelmintics in surface water. This study provides the levels, risks and even some tracer information of pollutants for better understanding of anthelmintics in southwest China.


Assuntos
Anti-Helmínticos/análise , Exposição Ambiental/análise , Rios/química , Poluentes Químicos da Água/análise , Adulto , Animais , Anti-Helmínticos/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Criança , China , Daphnia/efeitos dos fármacos , Sedimentos Geológicos/química , Humanos , Medição de Risco , Sacarose/análogos & derivados , Sacarose/análise , Poluentes Químicos da Água/toxicidade
6.
Commun Biol ; 4(1): 512, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941836

RESUMO

Rapidly assessing biodiversity is essential for environmental monitoring; however, traditional approaches are limited in the scope needed for most ecological systems. Environmental DNA (eDNA) based assessment offers enhanced scope for assessing biodiversity, while also increasing sampling efficiency and reducing processing time, compared to traditional methods. Here we investigated the effects of landuse and seasonality on headwater community richness and functional diversity, via spatio-temporal dynamics, using both eDNA and traditional sampling. We found that eDNA provided greater resolution in assessing biodiversity dynamics in time and space, compared to traditional sampling. Community richness was seasonally linked, peaking in spring and summer, with temporal turnover having a greater effect on community composition compared to localized nestedness. Overall, our assessment of ecosystem function shows that community formation is driven by regional resource availability, implying regional management requirements should be considered. Our findings show that eDNA based ecological assessment is a powerful, rapid and effective assessment strategy that enables complex spatio-temporal studies of community diversity and ecosystem function, previously infeasible using traditional methods.


Assuntos
Biodiversidade , Ecossistema , DNA Ambiental/análise , Rios/química , Estações do Ano , Análise Espaço-Temporal , Animais , DNA Ambiental/genética , Monitoramento Ambiental
7.
Ecotoxicol Environ Saf ; 220: 112373, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058675

RESUMO

The electronic conductivity of the metal oxides is generally increased by hybridization of highly conductive carbon supportive materials. In this present work, we have demonstrated a novel one-pot preparation of cerium niobate (CeNbO4) nanoparticles embedded with graphene oxide (GO/CeNbO4) composite, for ultrasensitive detection of the photographic developing agent, metol (MTL). The as-prepared GO/CeNbO4 was analyzed by various characterization techniques. The intensive characterization techniques were used to affirm the detailed structural moiety, size, morphology, and surface area of GO/CeNbO4. The GO/CeNbO4 modified glassy carbon electrode (GCE) affords a superior electrocatalytic activity toward MTL. The obtained amperometric response on the GO/CeNbO4/GCE holding an extremely low level detection of 10 nM and superior sensitivity of 10.97 µA µM-1 cm-2 toward MTL detection. Besides, the GO/CeNbO4/GCE also gives excellent selectivity, stability, repeatability, and reproducibility. We achieved excellent recovery results in real photographic solution and river water samples analysis with great accuracy. This work offers a novel insight into the growth of the carbon-based niobate family with electrochemical sensor applications.


Assuntos
Aminofenóis/análise , Técnicas Eletroquímicas/métodos , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Nanocompostos/química , Rios/química , Sulfatos/análise , Carbono/química , Catálise , Cério/química , Eletricidade , Eletrodos , Grafite/química , Indústrias , Nanopartículas/química , Nióbio/química , Óxidos/química , Compostos de Oxigênio/química , Fotografação , Reprodutibilidade dos Testes , Soluções , Água/química
8.
PLoS One ; 16(4): e0249566, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33819303

RESUMO

Habitat quality is an important indicator for evaluating the biodiversity provided by ecosystem. Estimating and scenario-simulating the dynamic evolution and future development trends of habitat quality under the influence of land-use change is significant in regional biodiversity conservation, formulating land-use planning, and maintaining the ecological environmental sustainability. In this article, we included the Huaihe River Economic Belt as the area of study because of its vital location in China and applied the CA-Markov and InVEST models to analyze the spatio-temporal evolution of habitat quality and to simulate the future development trends of habitat quality under three different land-use scenarios: fast urban growth scenario, farmland conservation-oriented scenario, and ecological conservation-oriented scenario. The results showed that the land-use change in the Huaihe River Economic Belt was mostly represented by the continuous increase of the built-up area, whereas other land types all declined in area from 1995 to 2015. The land-use changes under these three abovementioned alternative future scenarios with different development orientations were considerably different. The built-up area has been shown to expand rapidly to occupy other land types on a large scale under the fast urban growth scenario. Urban land increased slightly and a large area of rural residential land would be converted into farmland under the farmland conservation-oriented scenario. The built-up area and farmland might decrease while woodland, grassland and water would increase in extent of areas under the ecological conservation-oriented scenario. Habitat quality has been shown to be generally poor, continuing to decline from 1995 to 2015, while its spatial distribution was higher in the southwest and northeast areas and lower in the central regions. The future habitat quality would display a downward trend under the fast urban growth and farmland conservation-oriented scenarios with a further deterioration of the ecological environment, while the ecological conservation-oriented scenario predicted the converse trend that the ecological environment would be improved productively. This study may be useful for understanding the impact of land-use dynamics on biodiversity. The research results can provide a scientific basis for the decision-makers to formulate biodiversity conservation and land management policies.


Assuntos
Biodiversidade , Evolução Biológica , Simulação por Computador , Conservação dos Recursos Naturais , Ecossistema , Rios/química , Urbanização/tendências , Monitoramento Ambiental , Humanos
9.
Aquat Toxicol ; 234: 105812, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33799112

RESUMO

The subpopulation of the Irrawaddy dolphin (Orcaella brevirostris) living in the Mekong River, Cambodia, is considered to be critically endangered. The aim of the investigation was to gain information about the genetic variation, health status and exposure to toxic compounds of these dolphins. Tissue samples from 27 Irrawaddy river dolphins found dead along the Mekong River between 2004 and 2009 were analysed with regards to genetics, pathology and ecotoxicology. Genetic maternal lineage detection, based on polymorphisms of the mitochondrial d-loop sequences, was performed. Data indicate a genetic separation of the Mekong dolphins from both the coastal population and the Mahakam dolphins. Pathological investigations revealed acute moderate multifocal suppurative bronchopneumonia, moderate periportal hepatic lipidosis, moderate diffuse hepatic atrophy and acute severe diffuse suppurative leptomeningitis. Residue levels of organochlorines and polybrominated diphenyl ethers in Irrawaddy dolphins from the Mekong River were lower than the concentrations reported for other cetaceans in the coastal and riverine waters of Asia, except for Dichlorodiphenyltrichloroethane. A high percentage of organic mercury compared to the immuno-toxic methylmercury was observed. Due to numerous confounding factors, it is not possible to relate levels of pollutants to observed morphological lesions. However, it is likely that chemical contaminants do adversely impact on the health of the Irrawaddy dolphins at present, and have also affected previous generations.


Assuntos
Golfinhos/fisiologia , Rios/química , Poluentes Químicos da Água/toxicidade , Animais , Broncopneumonia/patologia , Camboja , Golfinhos/genética , Variação Genética , Éteres Difenil Halogenados/análise , Éteres Difenil Halogenados/toxicidade , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/toxicidade , Fígado/química , Fígado/efeitos dos fármacos , Fígado/metabolismo , Compostos Organomercúricos/toxicidade , Poluentes Químicos da Água/análise
10.
Ecotoxicol Environ Saf ; 215: 112141, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33740491

RESUMO

Current Chinese surface water environmental quality standard GB3838-2002 for ammonia fails to take water quality factors and native organism distributions in different basins into consideration. In this study, ammonia toxicity tests were performed using three aquatic organisms native to the Shaying River Basin (China). Published ammonia toxicity data with pH and temperature, and toxicity data acquired in this study were used to establish water quality criteria. The final criterion maximum concentration (CMC) and criterion continuous concentration (CCC) for the Shaying River Basin were 5.09 and 1.36 (mg total ammonia nitrogen (TAN))/L (pH 7 and 20 °C), respectively. In addition, based on the corresponding relationship between ammonia toxicity and temperature and pH, the ecological risk assessment of ammonia was conducted in different seasons for the Shaying River using a tiered approach of both hazard quotient (HQ) and the joint probability (JPC) methods. Two methods gave consistent results: the ecological risks of ammonia to aquatic species in the Shaying River Basin were severe and the risk could be ranked as wet season > flat season > dry season. It is therefore indicating that monitoring, evaluation, and early warning of ammonia pollution need to be taken to prevent and control the risks posed by ammonia pollution, especially for wet season (because of high temperatures and pH) or flat season (because of high pH values). We hope the present work could provide valuable information to manage and control ammonia pollution in the Shaying River Basin.


Assuntos
Amônia/análise , Poluentes Químicos da Água/análise , Amônia/toxicidade , Organismos Aquáticos , China , Monitoramento Ambiental/métodos , Nitrogênio , Medição de Risco/métodos , Rios/química , Estações do Ano , Testes de Toxicidade , Poluentes Químicos da Água/toxicidade , Qualidade da Água/normas
11.
Ecotoxicol Environ Saf ; 215: 112153, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33773147

RESUMO

Long-term pesticide water concentrations were investigated in four agricultural streams and their mixture toxicity on algae was assessed, based on realistic (i.e. observed) concentrations in laboratory tests using (i) natural weekly water samples and (ii) reconstituted pesticide-spiked water samples representing mixtures with predicted high mixture. This approach both covered the full complexity of natural water samples and the controlled approach of reconstituted water samples. Long-term monitoring data (time-integrated, weekly samples) revealed more than 11 pesticides (range 11.0 ± 0.25-24.0 ± 0.44) in 75% or more of the almost 1600 samples collected between 2002 and 2018. ∑TUalgae exceeded 0.1 for 29 observations (or 1.8%). Despite the multitude of pesticides in a sample, ∑TUalgae was frequently set by one or a few dominating pesticides that contribute to more than 90% of the mixture's toxicity. Algal growth inhibition tests with in situ stream water showed a high frequency of inhibition, despite the low ∑TU for most of these samples (range 0.000014-0.3858). These "false positive" results were attributed to confounding effects of turbidity, the complexation of nutrients, and toxic effects of metals and/or other unknown contaminants. Algal inhibition tests with spiked reconstituted water showed significant inhibitory effects in the range of 1-10x the ∑TUalgae observed in worst-case field samples. Although these tests disregard the chemical complexity of natural water, they show that inhibitory effects of pesticides on algae may occur at the ∑TUalgae observed in monitoring. Furthermore, considering that the ∑TUalgae of stream water are based on weekly average concentrations and likely underestimate short-term peak concentrations of pesticides, these results strongly suggest that inhibitory effects on algae may occur in the agricultural streams of southern Sweden. We conjecture, however, that the rapid recovery of algae contributes to ameliorate these short-term effects and that pesticide contamination should be seen as one of many stressors in the streams that drain agricultural landscapes.


Assuntos
Monitoramento Ambiental , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Agricultura , Animais , Laboratórios , Metais , Rios/química , Suécia
12.
PLoS One ; 16(2): e0245379, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33539444

RESUMO

At least 2.1 billion people around the world use contaminated drinking water, causing 485,000 diarrheal deaths each year, mostly among children under 5 years old. A study conducted 10 years ago in Bafoussam (West Cameroon) recorded concentrations of bacteria among surface and groundwater. High levels of bicarbonates, phosphates, chlorides and suspended matters were also found. The aim of this study was to assess the microbiological and chemical qualities of domestic water sources in 5 localities of the West region of Cameroon. Water samples from 22 water sources (wells, springs, water drilling and river) were aseptically collected in plastic bottles and transferred in 50 ml sterile tubes. For chlorinated water sources, 1 ml of Thiosulfate was added to the water sample; immediately placed in an ice box and transported to the laboratory for analysis. Water temperature and pH were measured on site. The microbiological quality of water was determined by testing Total Coliforms (TC) using the Micro Biological Survey method. 1 ml of each water sample was inoculated in the MBS vial initially rehydrated with 10 ml of sterile distilled water. The initial color of the vials is red. Color changes were monitored at three different time intervals (12h, 19h and 24h), corresponding to three levels of contamination. The chemical quality of water was assessed using micronucleus (MN) test in selected Vicia faba seeds secondary root tips permanently mounted in Dibutylphthalate Polystyrene Xylene mountant for histology after 72 hours of direct exposition in water samples and in dark. The mitotic indices and MN frequencies were evaluated in 10 root tips per site analysing 5000 cells per tip. Statistical analyses were done using Stata IC/15.0 software. The Student t-test was used for mean comparison and the significance level was set at 1%. The majority of samples were collected from wells (63.6%). The mean water pH ranged from 5.5 to 8.3 and the temperature varied from 23 to 26°C. A very high concentration of TC [>103 CFU/ml] was found in 8 (36.4%) samples. 10 (45.5%) and 2 (9.1%) samples turned yellow at 19 and 24 hours respectively after incubation corresponding to TC concentration of [10

Assuntos
Técnicas Bacteriológicas/métodos , Água Potável/química , Água Potável/microbiologia , Testes para Micronúcleos/métodos , Raízes de Plantas/genética , Vicia faba/genética , Microbiologia da Água , Camarões , Estudos Transversais , Água Subterrânea/química , Água Subterrânea/microbiologia , Humanos , Concentração de Íons de Hidrogênio , Rios/química , Rios/microbiologia , Temperatura , Poluição da Água , Qualidade da Água , Poços de Água
13.
PLoS One ; 16(2): e0246719, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33571231

RESUMO

Discharge reduction, as caused by water diversion for hydropower, and fine sediments deposition, are prevalent stressors that may affect multiple ecosystem functions in streams. Periphytic biofilms play a key role in stream ecosystem functioning and are potentially affected by these stressors and their interaction. We experimentally assessed the interactive effects of discharge and fine sediments on biofilm metabolism in artificial indoor channels using a factorial split-plot design with two explanatory variables: water discharge (20, 39, 62, 141 and 174 cm3 s-1) and fine sediments (no sediment or 1100 mg L-1 of sediments). We incubated artificial tiles for 25 days in an unpolluted stream to allow biofilm colonization, and then placed them into the indoor channels for acclimation for 18 days. Subsequently, we manipulated water discharge and fine sediments and, after 17 days, we measured biofilm chlorophyll-a concentration and metabolism. Water velocity (range, 0.5 to 3.0 cm s-1) and sediment deposition (range, 6.1 to 16.6 mg cm-2) increased with discharge, the latter showing that the effect of increased inputs prevailed over sloughing. In the no-sediment treatments, discharge did not affect biofilm metabolism, but reduced chlorophyll-a. Sediments, probably as a consequence of nutrients released, promoted metabolism of biofilm and chlorophyll-a, which became independent of water discharge. Our results indicate that pulses of fine sediments can promote biofilm algal biomass and metabolism, but show interactive effects with discharge. Although discharge reduction can affect the abundance of basal resources for food webs, its complex interactions with fine sediments make it difficult to forecast the extent and direction of the changes.


Assuntos
Biofilmes/crescimento & desenvolvimento , Clorófitas/fisiologia , Sedimentos Geológicos/microbiologia , Rios/microbiologia , Biodiversidade , Biomassa , Clorofila A/metabolismo , Clorófitas/metabolismo , Sedimentos Geológicos/análise , Rios/química
14.
Proc Natl Acad Sci U S A ; 118(8)2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33593902

RESUMO

Terrestrial vegetation and soils hold three times more carbon than the atmosphere. Much debate concerns how anthropogenic activity will perturb these surface reservoirs, potentially exacerbating ongoing changes to the climate system. Uncertainties specifically persist in extrapolating point-source observations to ecosystem-scale budgets and fluxes, which require consideration of vertical and lateral processes on multiple temporal and spatial scales. To explore controls on organic carbon (OC) turnover at the river basin scale, we present radiocarbon (14C) ages on two groups of molecular tracers of plant-derived carbon-leaf-wax lipids and lignin phenols-from a globally distributed suite of rivers. We find significant negative relationships between the 14C age of these biomarkers and mean annual temperature and precipitation. Moreover, riverine biospheric-carbon ages scale proportionally with basin-wide soil carbon turnover times and soil 14C ages, implicating OC cycling within soils as a primary control on exported biomarker ages and revealing a broad distribution of soil OC reactivities. The ubiquitous occurrence of a long-lived soil OC pool suggests soil OC is globally vulnerable to perturbations by future temperature and precipitation increase. Scaling of riverine biospheric-carbon ages with soil OC turnover shows the former can constrain the sensitivity of carbon dynamics to environmental controls on broad spatial scales. Extracting this information from fluvially dominated sedimentary sequences may inform past variations in soil OC turnover in response to anthropogenic and/or climate perturbations. In turn, monitoring riverine OC composition may help detect future climate-change-induced perturbations of soil OC turnover and stocks.


Assuntos
Carbono/análise , Carbono/metabolismo , Ecossistema , Sedimentos Geológicos/análise , Rios/química , Solo/química , Atmosfera , Ciclo do Carbono , Sequestro de Carbono , Clima , Temperatura
15.
Arch Environ Contam Toxicol ; 80(2): 474-489, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33582838

RESUMO

This study provides data on the characteristic levels, spatial patterns, sources, and risk of n-alkanes (AHs) [octane, n-C8, to tetracontane, n-C40] and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments from the Escravos River Basin (ERB), Nigeria. The n-alkane and PAH concentrations in sediments were quantified by chromatographic methods. The concentrations of AHs and PAHs in the ERB sediments varied from 95 to 3430 µg g-1 and from 0.75 to 213 µg g-1, respectively. Both the concentrations of AHs and PAHs in ERB sediments exceeded their respective guideline values. The carbon preference index and other AH markers provide evidence that the AHs in the ERB sediments originated from petroleum sources. Ecological risk assessment indicated that the ecological risk relating to an organism's contact with PAHs in the ERB sediments was high. The possible carcinogenic risk arising from human exposure with PAHs in surface sediments through accidental oral ingestion and skin contact exceeded the safe level of 10-6, indicating a considerable probable cancer risk for fishermen and other inhabitants of the ERB. PAH isomer ratios and multivariate statistics suggested that the PAHs in sediments from the ERB originated from gas flaring inputs, discharges from oil drilling platforms, diesel engines, ships, and speed boats, and combustion of wood and other biomass.


Assuntos
Alcanos/análise , Monitoramento Ambiental , Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Sedimentos Geológicos/química , Humanos , Níger , Nigéria , Indústria de Petróleo e Gás , Poluição por Petróleo , Medição de Risco , Rios/química
16.
Ecotoxicol Environ Saf ; 213: 112069, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33631636

RESUMO

Anthropogenic disturbances, such as pollution discharge and damming, can lead to a global decline in biodiversity in aquatic ecosystems. However, how such disturbances affect microbial community composition and function remains poorly understood. In November 2019, we explored bacterial diversity, community composition and metabolic function in Lake Tianmuhu, China, and in its upstream dammed river, using Illumina MiSeq sequencing and Biolog EcoPlate method based on carbon source utilization. Our results revealed higher variations in bacterial α- and ß-diversity in the dammed river ecosystem than in the lake ecosystem. In addition, the dammed river and lake ecosystems were significantly different in bacterial community compositions and metabolic structures. No significant relationship between species richness and functional (metabolic) diversity was observed in this study. The site that was most impacted by domestic wastewater had the lowest taxonomic diversity but highest metabolic capacity and activity, suggesting that community composition rather than species diversity is more important in determining ecosystem functioning. Overall, our findings indicate that anthropogenic disturbances can significantly alter bacterial community and function, and taxonomic diversity is a weak proxy for ecosystem functioning in a natural freshwater habitat.


Assuntos
Lagos/microbiologia , Microbiota , Águas Residuárias , Microbiologia da Água , Bactérias , Biodiversidade , China , Ecossistema , Rios/química
17.
Ecotoxicol Environ Saf ; 213: 112073, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33639561

RESUMO

Seasonal variations in hydrogeochemical characteristics of groundwater were assessed from an intensive agricultural region to identify contaminants of concern that are a potential risk to human health. A total of 116 groundwater samples were collected grid-wise from an intensive agricultural region of confined Wanaparthy watershed to evaluate seasonal variations in hydrogeochemical processes of dissolved ions, nitrate health risk assessment and water quality during pre-monsoon (PRM) and post-monsoon (POM) seasons. The major ions concentration found in ascending order as PRM: F- < NO3-< SO42-< HCO3-< Cl- and K+< Mg+2< Ca+2< Na+ while POM: F- < NO3-< SO42-< Cl-< HCO3- and K+< Ca+2< Mg+2< Na+ respectively. Piper diagram for water-types shows PRM; Na-Cl type (70.68%) while POM; Ca-Mg-Cl type (39.66%) and Ca-HCO3 type (31.03%). Gibbs diagram explained the favorable environmental conditions as rock and evaporation dominance in both seasons. Spatial distribution map shows samples with higher and above permissible limits are found at/near to adjoining to higher-order streams and streams origin. As per the water quality index (WQI), 36.21% (PRM) and 60.34% (POM) fall in poor to unfit for drinking class. Hazard quotient (HQ) values of nitrate reach as high as for infants 1.31E + 01, children 1.23E + 01 and adults 4.68E + 00 respectively. Subsequently, HQ>1 with 68.97% of infants and 72.41% of children are in danger for non-carcinogenic ingestion of nitrate contaminated groundwater than in adults.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água/análise , Adulto , Agricultura , Criança , Fluoretos/análise , Água Subterrânea , Humanos , Índia , Lactente , Nitratos/análise , Medição de Risco , Rios/química , Estações do Ano , Sódio , Qualidade da Água/normas
18.
Nat Microbiol ; 6(4): 479-488, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33510474

RESUMO

Small lakes and ponds occupy an enormous surface area of inland freshwater and represent an important terrestrial-water interface. Disturbances caused by extreme weather events can have substantial effects on these ecosystems. Here, we analysed the dynamics of nutrients and the entire plankton community in two flood events and afterwards, when quasi-stable conditions were established, to investigate the effect of such disturbances on a small forest pond. We show that floodings result in repeated washout of resident organisms and hundredfold increases in nutrient load. Despite this, the microbial community recovers to a predisturbance state within two weeks of flooding through four well-defined succession phases. Reassembly of phytoplankton and especially zooplankton takes up to two times longer and features repetitive and adaptive patterns. Release of dissolved nutrients from the pond is associated with inflow rates and community recovery, and returns to predisturbance levels before microbial compositions recover. Our findings shed light on the mechanisms underlying functional resilience of small waterbodies and are relevant to global change-induced increases in weather extremes.


Assuntos
Clima Extremo , Água Doce/microbiologia , Microbiota , Chuva , Animais , Inundações , Cadeia Alimentar , Florestas , Água Doce/química , Nutrientes/análise , Plâncton/crescimento & desenvolvimento , Lagoas/química , Lagoas/microbiologia , Rios/química , Rios/microbiologia
19.
Sci Rep ; 11(1): 400, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33432041

RESUMO

The presence of microplastics (MPs) in the environment has generated global concerns. However, the explicit assessment of the effect of multiple anthropogenic activities on the existence of MPs in the freshwater system is scarcely reported. This study quantified anthropogenic activities and analyzed their relationship with MPs on a freshwater organism: the midge larvae (Diptera: Chironomidae). The study took place in an urban river and consisted of comparing the abundance and types of MPs. Our results highlight that, while industrial area was the most important variable contributing to the total MP concentration in midge larvae, residential area also influenced the concentration of microfibers in midge larvae. The impact of a residential area on the relative abundance of microfibers in each sample site was diluted by the proximity to an industrial area. In conclusion, we suggest that industrial areas are a potential source of MP pollution in river sediment, and midge larvae can be a good indicator of the MP concentrations in urban river systems. Quantifying anthropogenic activities can help discern their effects on MP concentration in a river system and promote management strategies.


Assuntos
Biotransformação/fisiologia , Chironomidae/fisiologia , Microplásticos/farmacocinética , Rios , Animais , Organismos Aquáticos , Chironomidae/metabolismo , Cidades , Monitoramento Ambiental , Comportamento Alimentar/fisiologia , Água Doce , Sedimentos Geológicos/química , Sedimentos Geológicos/parasitologia , Resíduos Industriais , Microplásticos/química , Microplásticos/toxicidade , Rios/química , Rios/parasitologia , Taiwan , Poluentes Químicos da Água/química , Poluentes Químicos da Água/farmacocinética , Poluentes Químicos da Água/toxicidade
20.
J Fish Biol ; 98(5): 1410-1420, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33483946

RESUMO

Anthropogenic effects on the aquatic environment are ever present and ever increasing and while a plethora of aquatic contaminants are known to affect fishes, one ubiquitous and increasingly prevalent world-wide urban runoff pollutant is frequently disregarded, and that is pet waste. While dog waste has been identified as a significant factor contributing to bacteria and nutrient loading within receiving waters and the associated water quality changes are known to affect fishes, the impact of uncollected dog faeces on urban fish populations has never been directly investigated. In this study we exposed creek chub (Semotilus atromaculatus), a widespread tolerant stream minnow, to various realistic concentrations of dog waste as simulated urban park runoff testing both fresh and dried dog faeces in both stagnant and aerated water for 96 h to investigate the impact on fish survival and behaviour. Creek chub percentage mortality increased significantly relative to controls and across an exposure gradient and was likely caused by anoxic conditions. Survivors were initially smaller while those that died were initially larger and presented with abnormal abdominal subdermal lesions post-exposure. Additional indicators of physiological stress included significantly increased rates of aquatic surface respiration and changes in flume test derived swimming motivation metrics with increased exposure concentrations. Both mortality and behavioural responses were alleviated by aeration. Furthermore, trials with fresh and dried faeces differed only in time-to-death and swimming metrics where results from dried trials were similar to those from aerated experiments. Results demonstrated the impact that the global dog waste management problem can have on aquatic communities with effects on creek chub likely to be more severe for less pollution-tolerant species and also likely to be exacerbated under future scenarios that consider climate change and increased urbanization.


Assuntos
Cyprinidae/fisiologia , Exposição Ambiental , Fezes , Natação/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Cães , Rios/química , Análise de Sobrevida , Urbanização , Poluentes da Água/toxicidade
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