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1.
Mar Pollut Bull ; 159: 111482, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892917

RESUMO

Microplastics have received widespread attention as an emerging contaminant, but limited information was available during wetland restoration. The occurrence and characteristics of microplastics and their interaction with heavy metals in surface sediments from the Jinjiang Estuarine restored mangrove wetland were investigated. The abundance of microplastics ranged from 490 ± 127.3 to 1170 ± 99.0 items/500 g dry sediment, and the restored regions were much higher than mudflats, indicating mangrove restoration promoted its accumulation. Polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) were the main materials of microplastics after Raman spectroscopy identification. SEM-EDS images illustrated the mechanical erosion and chemical weathering on microplastics' surface, and Cr, Zn, Pb, and Cd were observed in elemental composition. The contents of Cr, Ni, Cu, Zn, Pb, As, and Cd accumulated in microplastics were not correlated with their total concentrations in sediments except for Hg, indicating that they might not be derived from sediments.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Microplásticos , Plásticos , Áreas Alagadas
2.
Mar Pollut Bull ; 159: 111495, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892925

RESUMO

Deposits of fluid mud on wave-dominated beaches are rare. Where they happen frequently and periodically, they can be associated with anthropic processes that bring fluid mud to the shoreface and surf zone. To determine the reason for the frequent deposition of fluid mud at Cassino Beach (Southern Brazil) in the 2014-2020 period, the La/Eu and Gd/Yb ratios in marine, beach, and adjacent Patos estuary sediments were investigated. Mud from the beach showed similar ratios of REE to dredged sediments from the harbor basin and navigation channel within the estuary. Industrial and port activity changes REE ratio in sediments of the navigation channel, and they are distinct from naturally deposited marine and estuarine sediments. We conclude that the mud deposition events at the beach are most likely associated with dredging processes in the estuary especially where overflow is the source of fluid mud on the beach shoreface.


Assuntos
Estuários , Sedimentos Geológicos , Brasil , Monitoramento Ambiental
3.
Environ Monit Assess ; 192(10): 626, 2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32897415

RESUMO

Benthic biotic indices are important ecological tools extensively used to understand the ecological quality of coastal wetlands. The present study aimed to assess the ecological status of Kodungallur-Azhikode estuary for the first time by using widely used benthic indices such as species richness (S), Shannon diversity index (H'log2), BENTIX, benthic opportunistic polychaetes amphipods (BOPA), AZTI's Marine Biotic Index (AMBI) and multivariate AMBI (M-AMBI). In the canonical correspondence analysis, salinity, dissolved oxygen, organic matter, sediment Eh, sediment pH and sand were identified as important variance descriptors. A single species of an opportunist, Americorophium triaeonyx, an amphipod belonging to the ecological group (EG) III, significantly contributed to the total macrofaunal density. Other dominant opportunistic species included Obelia bidentata (EGII), Arcuatula senhousia (EGIII), Cirolana fluviatilis (EGII), Prionospio cirrifera (EGIV) and Capitella sp. (EGV). The overall assessment indicated a 'good to moderate' condition in AMBI, 'good to poor' condition in M-AMBI, 'high to moderate' condition in BENTIX, 'high to poor' condition in BOPA and 'moderate to poor' condition in univariate Shannon diversity index. All the multivariate indices tested in the study were correlated with each other except BOPA and M-AMBI. The group of stations dominated with a sandy substrate and a moderate level of organic content indicated high to good conditions while other stations demonstrated moderate to poor conditions. However, no significant variation in indices tested between seasons was observed. The present study recommends long-term monitoring of benthic macroinvertebrate assemblages with proper taxonomic identification and functional trait analysis for better calibration of indices, which is the key factor for getting better results.


Assuntos
Estuários , Invertebrados , Animais , Ecossistema , Monitoramento Ambiental , Índia
4.
J Environ Sci (China) ; 97: 45-53, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933739

RESUMO

Estuarine wetland is the transitional interface linking terrestrial with marine ecosystems, and wetland microbes are crucial to the biogeochemical cycles of nutrients. The soil samples were collected in four seasons (spring, S1; summer, S2; autumn, S3; and winter, S4) from Suaeda wetland of Shuangtaizi River estuary, Northeast China, and the variations of bacterial community were evaluated by high-throughput sequencing. Soil properties presented a significant seasonal change, including pH, carbon (C) and total nitrogen (TN), and the microbial diversity, richness and structure also differed with seasons. Canonical correspondence analysis (CCA) and Mantel tests implied that soil pH, C and TN were the key factors structuring the microbial community. Gillisia (belonging to Bacteroidetes) and Woeseia (affiliating with Gammaproteobacteria) were the two primary components in the rhizosphere soils, displaying opposite variations with seasons. Based on PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) prediction, the xenobiotics biodegradation related genes exhibited a seasonal decline, while the majority of biomarker genes involved in nitrogen cycle showed an ascending trend. These findings could advance the understanding of rhizosphere microbiota of Suaeda in estuarine wetland.


Assuntos
Chenopodiaceae , China , Estuários , Filogenia , Rios , Estações do Ano , Solo , Microbiologia do Solo , Áreas Alagadas
5.
An Acad Bras Cienc ; 92(suppl 2): e20190045, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32935739

RESUMO

An extensive field survey was conducted to evaluate the spreading of the invasive estuarine bivalve Mytilopsis leucophaeata into the metropolitan region of Rio de Janeiro (Brazil), in which the single invaded site so far recorded is Rodrigo de Freitas Lagoon. A novel record is made to the Marapendi coastal lagoon, where M. leucophaeata mainly colonizes mangrove roots. A reef composed of druses above the unconsolidated substratum is recorded for the first time for this species. The fauna associated to agglomerates of M. leucophaeata was composed of eight taxa: polychaetes Alitta succinea and Polydora sp., amphipods Melita mangrovi and Elasmopus sp., barnacles Amphibalanus eburneus and A. improvisus, the crab Eurypanopeus cf. dissimilis and the gastropod Heleobia spp. Based on COI sequences, the haplotype diversity of M. leucophaeata invasion in Marapendi Lagoon is high, like that previously recorded in Rodrigo de Freitas Lagoon. The expansion of M. leucophaeata demands a continuous investigation, including the knowledge of its impacts on the biota.


Assuntos
Bivalves , Estuários , Animais , Brasil , Meio Ambiente
6.
Environ Monit Assess ; 192(10): 660, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32975666

RESUMO

We sampled the Klang estuary during the inter-monsoon and northeast monsoon period (July-Nov 2011, Oct-Nov 2012), which coincided with higher rainfall and elevated Klang River flow. The increased freshwater inflow into the estuary resulted in water column stratification that was observed during both sampling periods. Dissolved oxygen (DO) dropped below 63 µM, and hypoxia was observed. Elevated river flow also transported dissolved inorganic nutrients, chlorophyll a and bacteria to the estuary. However, bacterial production did not correlate with DO concentration in this study. As hypoxia was probably not due to in situ heterotrophic processes, deoxygenated waters were probably from upstream. We surmised this as DO correlated with salinity (R2 = 0.664, df = 86, p < 0.001). DO also decreased with increasing flushing time (R2 = 0.556, df = 11, p < 0.01), suggesting that when flushing time (> 6.7 h), hypoxia could occur at the Klang estuary. Here, we presented a model that related riverine flow rate to the post-heavy rainfall hypoxia that explicated the episodic hypoxia at Klang estuary. As Klang estuary supports aquaculture and cockle culture, our results could help protect the aquaculture and cockle culture industry here.


Assuntos
Estuários , Rios , Clorofila A , Monitoramento Ambiental , Humanos , Hipóxia , Nutrientes , Estações do Ano
7.
Bull Environ Contam Toxicol ; 105(3): 468-473, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32886144

RESUMO

Selenium (Se), iron (Fe), and free sulfides contents in pore waters were measured to study the liberation of soluble Se in suboxic conditions. The sediment core was collected in a salt marsh in Patos Lagoon estuary (southern Brazil), and it was obtained during a brackish water period, in a low intertidal stand vegetated by Spartina alterniflora. The redox potential (Eh), pH, andacid volatile sulfides (AVS) content were also investigated. Pore water results sustained the idea that S. alterniflora roots promote oxygen penetration to depths of ca. 10 cm below the salt marsh surface, increasing Eh and lowering the pH in this interval. High Se concentrations (e.g., 16.9 µg L-1), that are above US. EPA environmental criteria, were observed in the pore water to depths between 10 and 20 cm and are associated to low AVS contents and high concentrations of free sulfides. In the first 10 cm the lowering of Se contents probably happens due the low pH and biological volatilization of the metalloid.


Assuntos
Sedimentos Geológicos/química , Selênio/análise , Áreas Alagadas , Brasil , Estuários , Ferro/análise , Poaceae , Sulfetos/análise , Volatilização
8.
Ecotoxicol Environ Saf ; 202: 110976, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800235

RESUMO

In this study, we first reviewed the current research progress regarding the presence of environmental microplastics (MPs) in environment in China from 2010 to 2019. Results showed that: (1) current research has primarily focused on river and marine environments rather than soils and dusts, mainly located in eastern China, i.e., the Yangtze river, Poyang lake, Dongting lake, Yellow sea, and Bohai sea; (2) the abundance of MPs found in water bodies (sediments) of the rivers in China ranged from 3.9 to 7900 items·m-3 (19.0 × 103-13600.5 × 103 items·km-2), and 20-24300 items·kg-2 (170-5500 × 106 items·km-2) in the sediments, respectively; in lake water the range was 340-8900 items·m-3 (5 × 103-340 × 105 items·km-2) and 8 to 1200 items·m-2/25-300 items·kg-1 in the sediments, respectively; in marine water the range was 0.003-540 items·m-3 (0-380,100 item·km-2) and 1.3-14700 item·kg-1 in the sediments, respectively; in fish, shellfish, and natural planktons from ocean and freshwater, the range was 0-57 items·individuals-1 (0-168 items·g-1); (3) The absorption and toxicological effects of MPs in freshwater and oceans have mainly focused on polyethylene (PE), polypropylene (PP), and polystyrene (PS); (4) the sources of microplastics in soils and dusts primarily come from urban/town activities; for rivers and lakes (estuary), they primarily come from urban activities; for coastal waters, fishing gear and nets, and the maritime activities were the main sources.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Lagos/química , Microplásticos/análise , Rios/química , Solo/química , Poluentes Químicos da Água/análise , China , Cidades , Poeira/análise , Estuários , Oceanos e Mares , Polietileno/análise , Polipropilenos/análise , Poliestirenos/análise
9.
J Environ Manage ; 271: 110993, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778283

RESUMO

Organic matter (OM) composition changed due to land use ─ land cover (LULC) and hydrology modification, has distinctive linkage towards sustainable environment management in tropical river systems. It is crucial in small river systems, which experience delay of freshwater flow to the estuaries due to headwater damming, also LULC alteration along the entire basin. In order to understand this fundamental linkage in tropical Zuari river-estuary (ZRE), we analyzed multi-proxy data of organic carbon to total nitrogen ratio (Corg/N), stable organic carbon isotope (δ13Corg) and lignin phenols measured in seasonally collected suspended particulate matter (SPM) and sediment samples. Results highlighted about moderate seasonality of OM tracers, with a significant effect of LULC alteration, which nevertheless a striking feature in monsoon-fed river-estuaries of peninsular India. Particulate Corg export from ZRE estimated to be 20 × 103 kg yr-1, was much lower as compared to tropical river-estuary systems elsewhere. OM fraction from vascular plant (mangroves) contributed to SPM and sediment was 15% and 40%, respectively, calculated using a Bayesian mixing calculation through Stable isotope analysis in R (SIAR). Presence of mudflat LULC in the estuarine region notably caused 20% decrease in Corg and 60% increase in lignin phenol (Λ8) as compared to their limits in upstream. This is although mudflat accounts only 3% of ZRE catchment. The degree of shifts in OM tracers highlights towards efficient entrapment, transformation and/or utilization of riverine OM in the mudflats of ZRE. Accelerated human induced LULC dampens the seasonality of OM characteristics and flow is highlighted through this study, which is essential towards sustainable environmental management practice in small rivers of India and World.


Assuntos
Estuários , Rios , Teorema de Bayes , Monitoramento Ambiental , Sedimentos Geológicos , Índia
10.
Environ Pollut ; 265(Pt B): 114941, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806444

RESUMO

Pesticides are potentially toxic to aquatic systems, even at low concentration, depending on their individual ecotoxicological properties and their mixture composition. Thus, to evaluate possible ecological stress due to pesticide load, a thorough assessment of the potential toxicity of pesticide mixtures is required. Here we report water discharge and quality data of an eastern Mediterranean micro-estuary (Alexander stream), targeting the temporal distribution of a pesticide mixture. Over 150 water samples were collected during 2 hydrological years representing base-flow and flood conditions. On average, each water sample contained 34 and 45 different pesticides with peak concentrations of 1.4 µg L-1 of Imidacloprid and 55 µg L-1 of Diuron during base-flow and flood events, respectively. Pesticide mixtures were potentially toxic to benthic invertebrates and algae during flood events, surpassing the toxicity benchmark with medians of 110% and 155%, respectively. The herbicide Diuron and the insecticide Imidacloprid were the main pesticides responsible for the high potential toxicity during flood events. The falling limb of the flood hydrographs was found to inflict the highest stress on the estuarine environment due to elevated toxicity combined with prolonged residence time of the water. Examination of the potential chronic toxicity of single compounds showed continuous stress for plants, algae, amphibians, crustaceans, insects and fish from nine pesticides. Our data show that the ecosystem of the Alexander micro-estuary is under a continuous chronic stress with acute peaks in potential toxicity during flood events and the period that follows them. We propose that analyzing a small set of flood-tail samples is needed for the evaluation of small estuarine ecosystems risk during the rainy season. From a management perspective, we suggest better control of application practices for Diuron in the watershed to minimize the stress to the estuarine ecosystem.


Assuntos
Praguicidas/análise , Poluentes Químicos da Água/análise , Animais , Ecossistema , Estuários , Rios
11.
Environ Pollut ; 265(Pt B): 115066, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806459

RESUMO

Hypoxia off the Changjiang Estuary (CE) and its adjacent waters is purported to be the most severe in China, attracting considerable concern from both the scientific community and the general public. Currently, continuous observations of dissolved oxygen (DO) levels covering hypoxia from its appearance to disappearance are lacking. In this study, twelve consecutive monthly cruises (from February 2015 to January 2016) were conducted. The consecutive spatiotemporal variations in hypoxia throughout the annual cycle were elucidated in detail, and the responses of annual variations in hypoxia to the different influential factors were explored. Overall, hypoxia experienced a consecutive process of expanding from south to north, then disappearing from north to south. The annual variations in hypoxia were mainly contingent on stratification variations. Among different stages, there was significant heterogeneity in the dominant factors. Specifically, low-DO waters initially appeared from the intrusion of nearshore Kuroshio branch current (NKBC), as NKBC intrusion provided a low-DO background and triggered stratification. Thereafter, stratification was enhanced and gradually expanded northward, which promoted the extension of low-DO areas. The formation of hypoxia was regionally selective, and more intense organic matter decomposition at local regions facilitated the occurrence and discontinuous distribution of hypoxia. Hypoxic zones were observed at the Changjiang bank and Zhejiang coastal region from August (most extensively at 14,800 km2) to October. Thereafter, increased vertical mixing facilitated the dissipation of hypoxia from north to south.


Assuntos
Estuários , Oxigênio/análise , China , Humanos , Hipóxia
12.
Environ Monit Assess ; 192(9): 566, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32767125

RESUMO

A large number of white hard clam farms are in the estuary shoreline of Saigon-Dongnai Rivers, which flow through Ho Chi Minh City, a megacity, and numerous industrial zones in the basin catchment area. In this study, eleven trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Hg, and Pb) in the hard clam Meretrix lyrata and its habitats including surface water, suspended particulate matter, and sediment were evaluated to understand the bioaccumulation of trace metals from the environment into the whole tissues of the hard clam as well as its different organs. The samples were collected monthly in dry, transition, and wet seasons of the southern part of Vietnam from March to September 2016. The results showed that seasonal and spatial variations of the studied metal concentrations in the hard clam M. lyrata might be influenced by the sea current as well as the surface runoff in the rainy season. The relationship between condition index and the element concentrations in M. lyrata might be affected by the living environment conditions and farming methods. In addition, the hazard index values of all trace elements in the hard clam M. lyrata harvested in the sampling time show that the hard clams farmed in the study area were safe for local consumers.


Assuntos
Bivalves , Metais Pesados/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Animais , Bioacumulação , Cidades , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Vietnã
13.
Environ Monit Assess ; 192(9): 585, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32809133

RESUMO

Wetlands are carbon pools for terrestrial ecosystems and play an important role in the global carbon cycle. The Nanhui tidal flat is located at the Yangtze River estuary and has been disturbed by various human activities. However, the effect of human activities on the carbon accumulation capability and carbon storage of wetlands in the Nanhui tidal flat is poorly understood. In this study, the annual carbon accumulation capability and carbon storage of three types of Spartina alterniflora Loisel. wetlands in the Nanhui tidal flat, which were defined as a natural wetland, silt-promoting wetland, and artificial restored wetland, were evaluated by analyzing the plant carbon fixation capability, soil carbon emissions, and soil organic carbon (SOC) density. The results showed that the three wetlands all had a carbon sink effect and the natural wetland, artificial restored wetland, and silt-promoting wetland annually accumulated 7.94, 7.14, and 6.33 kg m-2 CO2, respectively. The existing SOC density in the subsurface soil (0-40 cm) in the natural wetland, silt-promoting wetland, and artificial restored wetland was 23.26, 17.95, and 12.21 kg m-2 CO2, respectively. The natural wetland, with no human disturbance, had a longer duration of waterlogging and greater tidal nutrition inputs than the other wetlands, resulting in a higher plant biomass and lower soil respiration (SR). It therefore had the strongest carbon accumulation capability and highest SOC storage.


Assuntos
Estuários , Áreas Alagadas , Carbono/análise , China , Ecossistema , Monitoramento Ambiental , Rios , Solo
14.
J Environ Manage ; 273: 111151, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32758912

RESUMO

Anaerobic oxidation of methane with denitrification (DAMO), as an important microbial process regulating methane emission, has been widely reported in freshwater ecosystems. However, the DAMO process and associated biogeochemical controls in estuaries remain poorly understood. Here, we used 13C- and 15N-labelling experiments to quantify the potential rates of DAMO and determined the crucial factors controlling the DAMO rates in the sediment of Yangtze Estuary. Potential rates of DAMO varied greatly across the estuary, ranging from 0.07 to 0.28 nmol CO2 g-1 d-1. Salinity negatively affected the DAMO and also showed an indirectly negative influence on DAMO process by high salinity inhibition on NO3- availability and denitrification. Nitrate concentrations were significantly correlated with the DAMO rates. Denitrification rates showed positive correlation with DAMO rates, implying that nitrate reduction drives the DAMO process. Sediment total organic carbon and NH4+ had important effects on DAMO rates. These results together indicate that DAMO process can occur and the DAMO rates were mainly controlled by sediment NO3- and denitrification in estuary. We further conclude that increasing NO3- load can drive the DAMO process with more important implications on methane sink in estuarine ecosystems.


Assuntos
Estuários , Metano , Anaerobiose , Desnitrificação , Ecossistema , Sedimentos Geológicos , Nitritos , Oxirredução , RNA Ribossômico 16S
15.
Mar Pollut Bull ; 159: 111494, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32739632

RESUMO

The source, distribution, and potential toxicity of sedimentary polycyclic aromatic hydrocarbons (PAHs) along the mouth bar of the Yangtze River Estuary were investigated. Total concentrations of 17 PAHs in the study area ranged from 34.94 to 580.26 ng/g (mean value 146.31 ng/g). Results of PMF model revealed that mixed vehicle emissions (38.43%), natural gas combustion (24.98%), biomass combustion (20.76%) and coal combustion (15.83%) were sources of these sedimentary PAHs. The ERL/ERM, TEL/PEL and TEC/PEC values showed that the potential toxicity of PAHs was at low to medium level, but the presence of benzo[a]pyrene (BaP) and benzo[e]pyrene (BeP) requires more attention and research. Sedimentary PAHs pollution level in the three shoals (East Nanhui Shoal, Jiuduansha Shoal and Hengsha Shoal) was higher than that of the two passages (South Passage and North Passage), which demonstrates the possibility of restoration of the adjacent shoals by dredged soils in terms of PAHs pollution.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Boca/química , Medição de Risco , Rios
16.
Mar Pollut Bull ; 159: 111521, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32763558

RESUMO

Plastic pollution is a concern in many nearshore ecosystems, and it is critical to understand how microplastics (plastics <5 mm in length) affect nearshore marine biota. Here, we report the presence of microplastics in the benthic, upside-down jellyfish (Cassiopea xamachana) across three estuaries in south Florida. Microplastics were recovered from Cassiopea using an acid digestion, then enumerated via microscopy, and identified using micro Fourier-transform interferometer (µFTIR) analysis. Out of 115 specimens analyzed, 77% contained microplastics. Bell diameter and number of plastics per individual varied significantly across locations with the highest plastic densities and bell diameter observed in individuals from Big Pine Key, followed by Jupiter, and Sarasota. µFTIR analysis confirmed that synthetic microfibers were the dominant microplastic measured at all three locations and may indicate Cassiopea as potential sinks of microplastic. Cassiopea may be used as bioindicators of microplastic contamination in the future, allowing for potential plastic pollution mitigation.


Assuntos
Estuários , Poluentes Químicos da Água/análise , Animais , Ecossistema , Monitoramento Ambiental , Florida , Microplásticos , Plásticos
17.
Mar Pollut Bull ; 159: 111473, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32853847

RESUMO

Due to rapid urbanization and industrialization, heavy metal (HM) pollution in coastal areas of the East China Sea (ECS) has attracted extensive attention. This article attempts to review recent studies on the temporal and spatial distributions, ecological risks, and possible sources of HMs in typical bays and estuaries of ECS. The levels of HMs are closely related to local economic development and local characteristics. The anthropogenic activities and the particle size of sediments are important factors affecting the distribution of HMs. During the late 1970s to the 1990s, HMs levels in the Yangtze Estuary (YRE) sediments showed an upward tendency due to the increased emissions. However, HMs levels in the early 2000s were lower than that in the late 1970s to the mid-1990s. Cd caused serious pollution and brought potential ecological risks in the Yangtze Estuary, Hangzhou Bay (HZB), Sanmen Bay (SMB), and Quanzhou Bay (QZB). In Fujian province of China, the Quanzhou Bay was heavily polluted by HMs and high contents of HMs were found in biota. Among different species, molluscs in the coastal areas of ECS have the highest levels of HMs exceeding safety limits.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Estuários , Sedimentos Geológicos
18.
Mar Pollut Bull ; 158: 111383, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753173

RESUMO

The estuaries of populated catchments have been documented as hotspots of plastic pollution. In this study, microplastics (0.355-5.0 mm) and large plastic debris (>5.0 mm) of surface water collected from the Inner Lingding Bay of the Pearl River Estuary (PRE) were quantified and categorized according to their size, shape, colour and composition. Both microplastics and large plastic debris were detected at all sampling sites with mean abundances of 2.376 ± 0.700 n/m3 and 0.110 ± 0.039 n/m3, respectively. Microplastics constitute 95.4% of the total abundance by number. The average microplastic concentration in the inner PRE was almost 3.5 times higher than that in the central PRE, indicating a positive correlation between plastic concentration and proximity to the river mouth. This result reveals the important role of rivers in transporting plastic debris from land to the oceans.


Assuntos
Plásticos , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Estuários , Microplásticos , Oceanos e Mares , Rios
19.
Mar Pollut Bull ; 158: 111412, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753196

RESUMO

The Conwy estuary was evaluated for sediment quality. Microtox bioassay revealed 38 of 39 sites were non-toxic. Hg ranged from 0.001 to 0.153 µg kg-1, mean 0.026 mg kg-1, Σ16 PAH from 18 to 1578 µg kg-1, mean 269 µg kg-1, Σ22 PAH, 18 to 1871 µg kg-1 mean to 312 µg kg-1, two sites had high perylene relative to ΣPAH. Σ22PAH correlated positively with TOC, clay and silt (R2 0.89, 0.92, 0.90) and negatively with sand. Multivariate statistics, delineated four spatial (site) and five variable (measurements) clusters. Spatial clustering relates to sediment grain size, in response to hydrodynamic processes in estuary; fine (clay to silt) sized sediments exhibit the highest Hg and PAH content, because these components partitioned into the fine fraction. Comparison to national and international environmental standards suggests Hg and PAH content of Conwy sediments are unlikely to harm ecology or transfer up into the human food chain.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Carbono/análise , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Humanos , Rios , Reino Unido , País de Gales
20.
Mar Pollut Bull ; 158: 111415, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753199

RESUMO

The mangrove sediment cores from middle and upper Zuari Estuary were studied for grain size, organic carbon, total and bioavailable metals (Fe, Mn, Zn, Pb) to evaluate the metal enrichment and pollution, along with the bioaccumulation of metals by edible bivalve Polymesoda erosa to understand the toxicity of metals. The distribution of metals varied between middle and upper estuary and was attributed to difference in metal source, hydrodynamics and/or post-depositional behavior. The pollution indices viz., contamination factor and pollution load index revealed metal pollution at both middle and upper estuary. Speciation of Mn, Zn and Pb indicated their bioavailability in sediments, and the application of screening quick reference table and risk assessment code suggested possible harmful effects of Mn on biota. The concentration of metals in Polymesoda erosa was more than the standard permissible limit, at both middle and upper estuary indicating metal toxicity to Polymesoda erosa and human health.


Assuntos
Bivalves , Metais Pesados/análise , Poluentes Químicos da Água/análise , Animais , Bioacumulação , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Índia , Metais/análise
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