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1.
Nature ; 590(7844): 37-38, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33536641
2.
Water Sci Technol ; 83(4): 854-862, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33617492

RESUMEN

River water in industrial regions is a dynamic medium defined by random variables that cannot be described by linear equations. However, some water quality characteristics, e.g., pollutant concentrations, which look chaotically distributed are largely governed by deterministic laws resulting in periodic variations of water chemistry. Understanding this process will enable the researchers to analyse the history of the characteristics involved and to predict their future values. We provide further evidence of predictable, cyclic concentration behavior from the Iset River flowing through a heavily industrialized area in the Ob River basin, Ural Federal District, Russia. In particular, we found that the concentration of copper and nitrate can be characterized by pronounced fractals and quasi-cycles with predominant lengths of 7-8 and 4-5 months, respectively. Our results can improve forecast reliability and water use efficiency. Results from the Iset River could be potentially applicable to virtually any other river in the world, at least in temperate climate areas.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Agua Dulce , Reproducibilidad de los Resultados , Federación de Rusia , Contaminantes Químicos del Agua/análisis , Calidad del Agua
3.
Bull Environ Contam Toxicol ; 106(1): 153-159, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33392685

RESUMEN

Soil properties largely control the fate of mercury (Hg), including the synthesis of neurovirulent methylmercury (MeHg). Here, the freshwater snail (Cipangopaludina cahayensis), a snail species commonly bred in flooded farmland, was used in a test of biotoxicity exposure to explore the effects of soil components on Hg bioavailability. The results show that snails incubated on the surface of slightly Hg-polluted flooded soil (2.0 mg/kg) have MeHg concentrations of 7.9 ± 1.5 mg/kg, which greatly exceed the limit of contaminants in food in China (0.5 mg/kg). The addition of ferrous disulfide can significantly increase the MeHg concentrations in soils while reducing the concentrations of total Hg (THg) and MeHg levels in snails by 59.1% and 64.3%, respectively. Peat-derived fulvic acid has the capacity to reduce the MeHg concentrations in soils and snails by 23.8% and 33.2%, respectively, whereas it increases the dissolved Hg levels in overlying water by 104.3%. Moreover, Fe-Mn oxides and humic acid can consistently reduce THg and MeHg concentrations in snails. Overall, freshwater snails bred in Hg-polluted areas may suffer from a high risk of Hg exposure, and importantly, some soil components such as ferrous disulfide and humic acid have strong inhibitory effects on Hg bioaccumulation in snails.


Asunto(s)
Mercurio , Compuestos de Metilmercurio , Animales , Bioacumulación , China , Monitoreo del Ambiente , Agua Dulce , Mercurio/análisis , Caracoles , Suelo
5.
Environ Pollut ; 272: 116415, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33421660

RESUMEN

Declining emissions of persistent organic pollutants (POPs), subject to international control under the Stockholm convention, are not consistently reflected in biotic samples. To assess spatial and temporal variation in organochlorine pesticides and PCBs in UK freshwaters, we analysed tissues of a sentinel predator, the Eurasian otter, Lutra lutra between 1992 and 2009. Past declines in otter populations have been linked to POPs and it is unclear whether otter recovery is hampered in any areas by their persistence. PCBs, DDT (and derivatives), dieldrin and HCB were detected in over 80% of 755 otter livers sampled. Concentrations of ∑PCB, ∑DDT and dieldrin in otter livers declined across the UK, but there was no significant time trend for ∑PCB-TEQ (WHO toxic equivalency, Van den Berg et al., 2006) or HCB. In general, higher concentrations were found in the midlands and eastern regions, and lowest concentrations in western regions. Concentrations of PCBs and HCB in otters increased near the coast, potentially reflecting higher pollutant levels in estuarine systems. Decades after legislative controls, concentrations of these legacy pollutants still pose a risk to otters and other freshwater predators, with spatially widespread exceedance of thresholds above which reproduction or survival has been reduced in related species.


Asunto(s)
Contaminantes Ambientales , Nutrias , Plaguicidas , Bifenilos Policlorados , Contaminantes Químicos del Agua , Animales , Contaminantes Ambientales/análisis , Agua Dulce , Plaguicidas/análisis , Bifenilos Policlorados/análisis
6.
Sci Total Environ ; 764: 144293, 2021 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-33385655

RESUMEN

River ecosystems are the most important resource of surface freshwater, but they have frequently been contaminated by excessive nutrient input of nitrogen (N) and phosphorus (P) in particular. An efficient and economic river water treatment technology that possesses the capacity of simultaneous N and P removal is urgently required. In this study, a solar-driven, self-sustainable electrolytic treatment was conducted in situ to intensify N and P removal from eutrophic river water. Solar panel was applied to provide the electrolysis setups with energy (voltage 10 ± 0.5 V), and the current density was controlled to be 0.06 ± 0.02 mA cm-2. Results indicated that the average removal efficiencies of total N (TN) and total P (TP) under electrolysis conditions reached 72.4 ± 11.7 and 13.8 ± 5.3 mg m-2 d-1, which were 3.7- and 4.7-fold higher compared to untreated conditions. Enhanced TN removal mainly reflected the abatement of nitrate N (NO3--N) (80.6 ± 4.1%). The formation of ferric ions through the electro-dissolution of the sacrificial iron anode improved TP removal by coprecipitation with SPS. Combined high-throughput sequencing and statistical analyses revealed that electrolysis significantly reshaped the microbial communities in both the sediment-water interface and suspended sediment (SPS), and hydrogenotrophic denitrifiers (e.g., Hydrogenophaga) were highly enriched under electrolysis conditions. These findings indicated that in situ electrolysis is a feasible and effective technology for intensified nutrient removal from river water.


Asunto(s)
Microbiota , Eliminación de Residuos Líquidos , Electrólisis , Agua Dulce , Nitrógeno , Nutrientes , Fósforo , Ríos , Agua
7.
Environ Sci Pollut Res Int ; 28(7): 8945-8952, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33405148

RESUMEN

Eels are exposed to Ca2+ changes during migration between seawater and freshwater. The gill is the main organ of active calcium transport and has a large surface area to be particularly sensitive to environmental changes in the aquatic environment. In this research, we focused on the morphological changes of gill tissues when eels are faced with the environmental calcium challenges. Based on the results of hematoxylin and eosin (HE) staining and immunohistochemistry, compared with the control group (normal Ca2+ environment), the filament and lamella lengths and lamellar frequency (LF) appeared higher in high calcium environment and lower in deficient calcium environment, while the lamella width and filamental lamellar surface area (SAFL) decreased in high calcium environment and increased in deficient calcium environment. And there was no difference in the number filaments in first right gill arch in the three Ca2+ water environment. Transmission electron microscopy was employed to examine the ultrastructural changes in gills in different Ca2+ water environment. The nucleus and endoplasmic reticulum had a tendency to expand in calcium-deficient water, but had a tendency to shrink in high-calcium water comparing with the control group. This study provides the support that branchial surface areas are regulated in different Ca2+ waters through a list of calcium transporters including CACNB2.


Asunto(s)
Calcio , Branquias , Animales , Anguilas , Peces , Agua Dulce
8.
Water Res ; 191: 116767, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33418487

RESUMEN

Bioindication has become an indispensable part of water quality monitoring in most countries of the world, with the presence and abundance of bioindicator taxa, mostly multicellular eukaryotes, used for biotic indices. In contrast, microbes (bacteria, archaea and protists) are seldom used as bioindicators in routine assessments, although they have been recognized for their importance in environmental processes. Recently, the use of molecular methods has revealed unexpected diversity within known functional groups and novel metabolic pathways that are particularly important in energy and nutrient cycling. In various habitats, microbial communities respond to eutrophication, metals, and natural or anthropogenic organic pollutants through changes in diversity and function. In this review, we evaluated the common trends in these changes, documenting that they have value as bioindicators and can be used not only for monitoring but also for improving our understanding of the major processes in lotic and lentic environments. Current knowledge provides a solid foundation for exploiting microbial taxa, community structures and diversity, as well as functional genes, in novel monitoring programs. These microbial community measures can also be combined into biotic indices, improving the resolution of individual bioindicators. Here, we assess particular molecular approaches complemented by advanced bioinformatic analysis, as these are the most promising with respect to detailed bioindication value. We conclude that microbial community dynamics are a missing link important for our understanding of rapid changes in the structure and function of aquatic ecosystems, and should be addressed in the future environmental monitoring of freshwater ecosystems.


Asunto(s)
Monitoreo Biológico , Ecosistema , Archaea/genética , Biomarcadores Ambientales , Monitoreo del Ambiente , Agua Dulce
9.
Water Res ; 191: 116812, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33461082

RESUMEN

Elevated levels of Escherichia coli (E. coli) are responsible for more designated freshwater stream impairments than any other contaminant in the United States. E. coli are intentionally used as a sentinel of fecal contamination for freshwaters because previous research indicates that salt concentrations in brackish or marine waters reduce E. coli survival, rendering it a less effective indicator of public health risks. Given increasing evidence of freshwater salinization associated with upland anthropogenic land-use, understanding the effects on fecal indicators is critical; however, changes in E. coli survival along the freshwater salinity range (≤ 1500 µS cm-1) have not been previously examined. Through a series of controlled mesocosm experiments, we provide direct evidence that salinization causes E. coli survival rates in freshwater to increase at conductivities as low as 350 µS cm-1 and peak at 1500 µS cm-1, revealing a subsidy-stress response across the freshwater-marine continuum. Furthermore, specific base cations affect E. coli survival differently, with Mg2+ increasing E. coli survival rates relative to other chloride salts. Further investigation of the mechanisms by which freshwater salinization increases susceptibility to or exacerbates bacterial water quality impairments is recommended. Addressing salinization with nuanced approaches that consider salt sources and chemistry could assist in prioritizing and addressing bacterial water quality management.


Asunto(s)
Escherichia coli , Agua Dulce , Bacterias , Ríos , Salinidad
10.
Elife ; 102021 01 19.
Artículo en Inglés | MEDLINE | ID: mdl-33461660

RESUMEN

While traditional microbiological freshwater tests focus on the detection of specific bacterial indicator species, including pathogens, direct tracing of all aquatic DNA through metagenomics poses a profound alternative. Yet, in situ metagenomic water surveys face substantial challenges in cost and logistics. Here, we present a simple, fast, cost-effective and remotely accessible freshwater diagnostics workflow centred around the portable nanopore sequencing technology. Using defined compositions and spatiotemporal microbiota from surface water of an example river in Cambridge (UK), we provide optimised experimental and bioinformatics guidelines, including a benchmark with twelve taxonomic classification tools for nanopore sequences. We find that nanopore metagenomics can depict the hydrological core microbiome and fine temporal gradients in line with complementary physicochemical measurements. In a public health context, these data feature relevant sewage signals and pathogen maps at species level resolution. We anticipate that this framework will gather momentum for new environmental monitoring initiatives using portable devices.


Asunto(s)
Agua Dulce/microbiología , Metagenoma/genética , Metagenómica/métodos , Microbiota/genética , Secuenciación de Nanoporos/métodos , Microbiología del Agua , Bacterias/clasificación , Bacterias/genética , Secuencia de Bases , Análisis por Conglomerados , Biología Computacional/métodos , Monitoreo del Ambiente/métodos , Geografía , ARN Ribosómico 16S/genética , Ríos/microbiología , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie , Reino Unido
11.
Ecotoxicol Environ Saf ; 209: 111815, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33387774

RESUMEN

Mercury (Hg) is a global contaminant resulting of both natural processes and human activities. In aquatic environments, studies conducted on vertebrates highlighted changes of gene expression or activity of antitoxic and oxidative enzymes. However, although Hg is a highly toxic compound in aquatic environments, only a few studies have evaluated the lethal and sublethal effects of inorganic Hg on Gammarus sp. Therefore, this study aimed at evaluating the effects of inorganic Hg (HgCl2) on the expression of 17 genes involved in crucial biological functions or mechanisms for organisms, namely respiration, osmoregulation, apoptosis, immune and endocrine system, and antioxidative and antitoxic defence systems. The study was performed in males of the freshwater amphipod Gammarus pulex exposed to two environmentally relevant concentrations (50 and 500 ng/L) at two temperature regime fluctuations (16 °C and 20 °C +/-2 °C) for 7 and 21 days. Results showed that G. pulex mortality was dependent on Hg concentration and temperature; the higher the concentration and temperature, the higher the mortality rate. In addition, the Integrated Biomarker Response emphasized that HgCl2 toxicity was dependent on the concentration, time and temperature of exposure. Overall, antioxidant and antitoxic defences, as well as the endocrine and immune systems, were the biological functions most impacted by Hg exposure (based on the concentration, duration, and temperature tested). Conversely, osmoregulation was the least affected biological function. The results also demonstrated a possible adaptation of G. pulex after 21 days at 500 ng/L, regardless of the exposure temperature. This study allowed us to show that Hg deregulates many crucial biological functions after a short exposure, but that during a long exposure, an adaptation phenomenon could occur, regardless of temperature.


Asunto(s)
Anfípodos/fisiología , Expresión Génica/efectos de los fármacos , Mercurio/toxicidad , Temperatura , Contaminantes Químicos del Agua/toxicidad , Anfípodos/metabolismo , Animales , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Agua Dulce , Humanos , Masculino
12.
Ecotoxicol Environ Saf ; 208: 111646, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396166

RESUMEN

Contamination of aquatic ecosystems linked to anthropogenic activity is currently a major concern; therefore, ecotoxicological studies are needed to assess its effect on organisms. The main objective of this study was to investigate the effects of different pollutants on microalgae in search of sensitive biomarkers that can promote a common cytotoxic response regardless of the contaminant. Cultures of the freshwater microalga Chlamydomonas reinhardtii were exposed for 24 h to four chemicals, three emerging pollutants (benzophenone-3, bisphenol A and oxytetracycline) and one priority substance (atrazine). A cytometric panel was carried out to assess toxicity biomarkers including cellular growth, inherent cell properties, viability, vitality, cytoplasmic membrane potential and ROS levels. Lipid peroxidation, photosynthetic efficiency and transcriptional responses of photosynthesis- and oxidative stress-related genes using RT-qPCR were also studied. Some toxicity responses showed a similar pattern; a decrease in growth rate, vitality and photosynthetic efficiency and an increase in autofluorescence and in the number of cells with depolarised cytoplasmic membrane and were found for all chemicals tested. However, ATZ and OTC provoked a decrease in cell size, whereas BP-3 and BPA caused an increase in cell size, intracellular complexity and ROS levels and a decrease in cell viability. Assayed pollutants generally promoted an overexpression of genes related to cellular antioxidant defence system and a subexpression of photosynthesis-related genes. In addition to the traditional growth endpoint, cell vitality, autofluorescence and gene expression of catalase, glutathione peroxidase and Fe-superoxide dismutase were significantly affected for all chemicals tested, showing a common cytotoxic response. Among the tested substances, BP-3 provoked the strongest cytotoxic alterations on this microalga, pointing out that some emerging contaminants could be more harmful to organisms than priority pollutants.


Asunto(s)
Supervivencia Celular/efectos de los fármacos , Chlamydomonas reinhardtii/efectos de los fármacos , Microalgas/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Antioxidantes/metabolismo , Chlamydomonas reinhardtii/metabolismo , Ecotoxicología , Biomarcadores Ambientales/efectos de los fármacos , Agua Dulce/química , Agua Dulce/microbiología , Microalgas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Fotosíntesis/efectos de los fármacos
13.
Ecotoxicol Environ Saf ; 208: 111662, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396172

RESUMEN

Metal nanoparticles (MNPs) are employed in a variety of medical and non-medical applications. Over the past two decades, there has been substantial research on the impact of metallic nanoparticles on algae and cyanobacteria, which are at the base of aquatic food webs. In this review, the current status of our understanding of mechanisms of uptake and toxicity of MNPs and metal ions released from MNPs after dissolution in the surrounding environment were discussed. Also, the trophic transfer of MNPs in aquatic food webs was analyzed in this review. Approximately all metallic nanoparticles cause toxicity in algae. Predominantly, MNPs are less toxic compared to their corresponding metal ions. There is a sufficient evidence for the trophic transfer of MNPs in aquatic food webs. Internalization of MNPs is indisputable in algae, however, mechanisms of their transmembrane transport are inadequately known. Most of the toxicity studies are carried out with solitary species of MNPs under laboratory conditions rarely found in natural ecosystems. Oxidative stress is the primary toxicity mechanism of MNPs, however, oxidative stress seems a general response predictable to other abiotic stresses. MNP-specific toxicity in an algal cell is yet unknown. Lastly, the mechanism of MNP internalization, toxicity, and excretion in algae needs to be understood carefully for the risk assessment of MNPs to aquatic biota.


Asunto(s)
Agua Dulce/microbiología , Nanopartículas del Metal/toxicidad , Microalgas/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Bioacumulación , Ecosistema , Cadena Alimentaria , Agua Dulce/química , Metales/metabolismo , Metales/toxicidad , Microalgas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Contaminantes Químicos del Agua/metabolismo
14.
Ecotoxicol Environ Saf ; 208: 111664, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396174

RESUMEN

Recently, the pollution of microplastics (MPs) in the global freshwater environment has become increasingly problematic, but there are few studies on the freshwater environment risks of MPs. The present study, therefore, has investigated the single and combined effects of MPs and lead (Pb) on the freshwater algal Microcystis aeruginosa. Results showed that Pb-only (>0.05 mg·L-1) promoted the growth of algal cells, while MPs-only (1 mg L-1) resulted in growth inhibition. However, compared with the corresponding concentration of Pb-only groups, the growth of algal cells was promoted in MPs + Pb treatments. MPs-only and Pb-only (0.5 mg L-1) both reduced the content of photosynthetic pigments and affected algal photosynthesis. The MPs-only treatment and MPs + Pb2+ (no pretreatment, 0.5 mg L-1 Pb2+) treatments showed significant cell aggregation. At the same time, MPs-only caused a significant increase in bound extracellular polysaccharides (bEPS), while 0.5 mg L-1 Pb reduced bEPS. Furthermore, under high Pb stress (0.5 mg L-1), the effects of combined MPs and Pb on chlorophyll content, antioxidant enzyme activity (peroxidase (POD), catalase (CAT)), and damage to algal cells were less compared to individual effects, and the combination of MPs and Pb had a synergistic effect on promoting aggregations of M. aeruginosa. These results demonstrate that single and combined effects of MPs and Pb can induce differential responses in the freshwater algal M. aeruginosa, which can have a significant impact on aquatic ecosystems.


Asunto(s)
Agua Dulce/microbiología , Plomo/toxicidad , Microcystis/efectos de los fármacos , Microplásticos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Antioxidantes/metabolismo , Clorofila/metabolismo , Sinergismo Farmacológico , Ecosistema , Agua Dulce/química , Microcystis/crecimiento & desarrollo , Microcystis/metabolismo , Fotosíntesis/efectos de los fármacos
15.
Ecotoxicol Environ Saf ; 208: 111666, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396176

RESUMEN

The chemical ecology of rotifers has been little studied. A yet unknown property is presented within some monogonant rotifers, namely the ability to produce an exogenic filamentous biopolymer, named 'Rotimer'. This rotifer-specific viscoelastic fiber was observed in six different freshwater monogonants (Euchlanis dilatata, Lecane bulla, Lepadella patella, Itura aurita, Colurella adriatica and Trichocerca iernis) in exception of four species. Induction of Rotimer secretion can only be achieved by mechanically irritating rotifer ciliate with administering different types (yeast cell skeleton, denatured BSA, epoxy, Carmine or urea crystals and micro-cellulose) and sizes (approx. from 2.5 to 50 µm diameter) of inert particles, as inductors or visualization by adhering particles. The thickness of this Rotimer is 33 ± 3 nm, detected by scanning electron microscope. This material has two structural formations (fiber or gluelike) in nano dimension. The existence of the novel adherent natural product becomes visible by forming a 'Rotimer-Inductor Conglomerate' (RIC) web structure within a few minutes. The RIC-producing capacity of animals, depends on viability, is significantly modified according to physiological- (depletion), drug- (toxin or stimulator) and environmental (temperature, salt content and pH) effects. The E. dilatata-produced RIC is affected by protein disruptors but is resistant to several chemical influences and its Rotimer component has an overwhelming cell (algae, yeast and human neuroblastoma) motility inhibitory effect, associated with low toxicity. This biopolymer-secretion-capacity is protective of rotifers against human-type beta-amyloid aggregates.


Asunto(s)
Biopolímeros/metabolismo , Rotíferos/metabolismo , Péptidos beta-Amiloides/farmacología , Animales , Biopolímeros/química , Biopolímeros/farmacología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Agua Dulce/microbiología , Humanos , Rotíferos/clasificación , Rotíferos/efectos de los fármacos , Temperatura
16.
Ecotoxicol Environ Saf ; 208: 111763, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396083

RESUMEN

Sulfate occurs naturally in the aquatic environment but its elevated levels can be toxic to aquatic life in freshwater environments. We investigated the toxicity of sulfate in humic, soft freshwater to whitefish (Coregonus lavaretus) from fertilization of eggs to hatching i.e. during the critical phases of whitefish early development. Anadromous Kokemäenjoki whitefish eggs and sperm during fertilization, embryos and larvae were exposed in the long-term 175-day incubation to seven different sodium sulfate (Na2SO4) concentrations from 44 to 2 000 mg SO4 L-1. Endpoint variables were the fertilization success, offspring survival and larval growth. Egg fertilization and early embryonic development were the most sensitive developmental stages of whitefish to sulfate, although the fertilization success and survival of embryos decreased only in the highest concentration of 2 000 mg SO4 L-1. The survival during late embryonic period, hatching and the 5-day larval period was high and no difference between the control and sulfate treatments were observed. LC50-values of sulfate for early embryonic period and for the entire embryonic and larval period was 1 413 and 1 161 mg L-1, respectively. The NOEC (No-observed Effect Concentration) of sulfate for the both periods was 1 207 mg L-1. The tolerance of whitefish early stages to sulfate toxicity seems to be on the same level as the tolerance of other salmonids' early stages.


Asunto(s)
Embrión no Mamífero/fisiología , Desarrollo Embrionario/efectos de los fármacos , Salmonidae/embriología , Sulfatos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Agua Dulce/química , Larva , Dosificación Letal Mediana , Masculino , Salmonidae/crecimiento & desarrollo , Espermatozoides
17.
Ecotoxicol Environ Saf ; 208: 111575, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396101

RESUMEN

Microplastics (MPs) have aroused widespread concern due to their extensive distribution in aquatic environments and adverse effects on aquatic organisms. However, the underlying toxicity of different kinds of MPs on freshwater microalgae has not been examined in detail. In this study, we investigated the effects of polyvinyl chloride (PVC), polystyrene (PS) and polyethylene (PE) MPs on the growth of Microcystis aeruginosa, as well as on its toxin production and oxidative stress. We found that all three kinds of MPs had an obvious inhibition effect on the growth of M. aeruginosa. Considering the results of antioxidant-related indicators, the activity of superoxide dismutase (SOD) and catalase (CAT), and cell membrane integrity were greatly affected with exposure to PVC, PS and PE MPs. Moreover, the content of intracellular (intra-) and extracellular (extra-) microcystins (MCs) had a noticeable increase due to the presence of PVC, PS, and PE MPs. Finally, according to the comprehensive stress resistance indicators, the resistance of M. aeruginosa to three MPs followed the order: PE (3.701)> PS (3.607)> PVC (2.901). Our results provide insights into the effects of different kinds of MPs on freshwater algae and provide valuable data for risk assessment of different types of MPs.


Asunto(s)
Microcystis/fisiología , Microplásticos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Antioxidantes/metabolismo , Catalasa/metabolismo , Agua Dulce , Microalgas/efectos de los fármacos , Microcistinas , Microcystis/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Plásticos/toxicidad , Polietileno , Poliestirenos/toxicidad , Cloruro de Polivinilo/toxicidad , Superóxido Dismutasa/metabolismo
18.
Ecotoxicol Environ Saf ; 208: 111628, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396148

RESUMEN

Metals may cause damage to the biota of contaminated environments. Moreover, using multiple endpoints in ecotoxicological studies is useful to better elucidate the mechanisms of toxicity of these compounds. Therefore, this study aimed to evaluate the effects of cadmium (Cd) and cobalt (Co) on growth, biochemical and photosynthetic parameters of the microalgae Raphidocelis subcapitata, through quantification of lipid classes composition, chlorophyll a (Chl a) content, maximum (ΦM) and effective (Φ'M) quantum yields and efficiency of the oxygen-evolving complex (OEC). Both metals affected the algal population growth, with an IC50-96h of 0.67 and 1.53 µM of Cd and Co, respectively. Moreover, the metals led to an increase in the total lipid content and reduced efficiency of OEC and ΦM. Cell density was the most sensitive endpoint to detect Cd toxicity after 96 h of treatment. Regarding Co, the photosynthetic parameters were the most affected and the total lipid content was the most sensitive endpoint as it was altered by the exposure to this metal in all concentrations. Cd led to increased contents of the lipid class wax esters (0.89 µM) and phospholipids (PL - at 0.89 and 1.11 µM) and decreased values of triglycerides (at 0.22 µM) and acetone-mobile polar lipids (AMPL - at 0.44 and 1.11 µM). The percentage of free fatty acids (FFA) and PL of microalgae exposed to Co increased, whereas AMPL decreased in all concentrations tested. We were able to detect differences between the toxicity mechanisms of each metal, especially how Co interferes in the microalgae at a biochemical level. Furthermore, to the best of our knowledge, this is the first study reporting Co effects in lipid classes of a freshwater Chlorophyceae. The damage caused by Cd and Co may reach higher trophic levels, causing potential damage to the aquatic communities as microalgae are primary producers and the base of the food chain.


Asunto(s)
Cadmio/toxicidad , Chlorophyceae/fisiología , Cobalto/toxicidad , Contaminantes Químicos del Agua/toxicidad , Chlorophyceae/efectos de los fármacos , Clorofila A , Ecotoxicología , Agua Dulce/química , Metales/farmacología , Microalgas/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Complejo de Proteína del Fotosistema II
19.
Arch Environ Contam Toxicol ; 80(1): 183-207, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33392777

RESUMEN

Evaluation of the hydrogeochemical processes governing the heavy metal distribution and the associated health risk is important in managing and protecting the health of freshwater resources. This study mainly focused on the health impacts due to the heavy metals pollution in a known Cretaceous-Tertiary (K/T) contact region (Tiruchinopoly, Tamilnadu) of peninsular India, using various pollution indices, statistical, and geochemical analyses. A total of 63 samples were collected from the hard rock aquifers and sedimentary formations during southwest monsoon and analysed for heavy metals, such as Li, Be, Al, Rb, Sr, Cs, Ba, pb, Mn, Fe, Cr, Zn, Ga, Cu, As, Ni, and Co. Ba was the dominant element that ranged from 441 to 42,638 µg/l in hard rock aquifers, whereas Zn was the major element in sedimentary formations, with concentrations that ranged from 44 to 118,281 µg/l. The concentrations of Fe, Ni, Cr, Al, Cr, and Ni fell above the permissible limit in both of the formations. However, the calculated heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and the degree of contamination (Cd) parameters were higher in the sedimentary formation along the contact zone of the K/T boundary. Excessive health risks from consumption of contaminated groundwater were mostly confined to populations in the northern and southwestern regions of the study area. Carcinogenic risk assessment suggests that there are elevated risks of cancer due to prolonged consumption of untreated groundwater. Ba, Sr, and Zn were found to be geochemically highly mobile due to the partitioning between the rock matrix and groundwater, aided by the formation of soluble carbonato-complexes. Factor analysis indicates that the metals are mainly derived from the host rocks and anthropogenic inputs are relatively insignificant. Overall, this study indicated that groundwater in K/T contact zones is vulnerable to contamination because of the favorable geochemical factors. Long-term monitoring of such contact zones is required to avert the potential health hazards associated with consumption of the contaminated groundwater.


Asunto(s)
Monitoreo del Ambiente/métodos , Sedimentos Geológicos/química , Agua Subterránea/química , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Agua Dulce/química , Humanos , India , Medición de Riesgo
20.
Ecotoxicol Environ Saf ; 211: 111905, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33453636

RESUMEN

The constant increase of heavy metals into the aqueous environment has become a contemporary global issue of concern to government authorities and the public. The study assesses the concentration, distribution, and risk assessment of heavy metals in freshwater from the Linggi River, Negeri Sembilan, Malaysia. Species sensitivity distribution (SSD) was utilised to calculate the cumulative probability distribution of toxicity from heavy metals. The aquatic organism's toxicity data obtained from the ECOTOXicology knowledgebase (ECOTOX) was used to estimate the predictive non-effects concentration (PNEC). The decreasing sequence of hazardous concentration (HC5) was manganese > aluminium > copper > lead > arsenic > cadmium > nickel > zinc > selenium, respectively. The highest heavy metal concentration was iron with a mean value of 45.77 µg L-1, followed by manganese (14.41 µg L-1) and aluminium (11.72 µg L-1). The mean heavy metal pollution index (HPI) value in this study is 11.52, implying low-level heavy metal pollutions in Linggi River. The risk quotient (RQ) approaches were applied to assess the potential risk of heavy metals. The RQ shows a medium risk of aluminium (RQm = 0.1125) and zinc (RQm = 0.1262); a low risk of arsenic (RQm = 0.0122) and manganese (RQm = 0.0687); and a negligible risk of cadmium (RQm = 0.0085), copper (RQm = 0.0054), nickel (RQm = 0.0054), lead (RQm = 0.0016) and selenium (RQm = 0.0012). The output of this study produces comprehensive pollution risk, thus provides insights for the legislators regarding exposure management and mitigation.


Asunto(s)
Metales Pesados/toxicidad , Contaminantes Químicos del Agua/toxicidad , Arsénico/análisis , Cadmio/análisis , Cobre/análisis , Ecotoxicología , Monitoreo del Ambiente , Agua Dulce , Hierro , Malasia , Manganeso , Metales Pesados/análisis , Níquel/análisis , Medición de Riesgo , Ríos , Contaminantes Químicos del Agua/análisis , Zinc/análisis
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