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1.
Environ Monit Assess ; 193(7): 414, 2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34117952

RESUMO

Despite increasing public concern about air and water pollution risks posed by concentrated animal feeding operation areas (CAFOs), there is little information about bioavailability and ecosystem impacts of agrochemicals used to increase productivity. In this study, we investigated the toxicity of wastewaters originating from beef cattle feeding operation on Daphnia pulex. Specifically, we assessed lethal and chronic sublethal exposure effects using various endpoints including survival, oxygen consumption, morphology, reproduction, and swimming behavior. Exposure assessments (acute and chronic) were performed with ten (10) surface water samples collected from on-site retention ponds designated as A, B, C, D, E, F, G, H, I, and R (reference site). Surface water samples were diluted to yield five concentrations (stock, 1 × , 2 × , 3 × , and 4 ×) as treatments and deionized water was used as control. Results showed site-specific and concentration-related effects on toxicity endpoints. Among treatments, significant (p < 0.05) increase in mortality rate (for A, E, F, and H) and decreasing total body length and width (for B, C, D, and G) of D. pulex were observed with increasing wastewater concentration. However, treatments did not have significant effect on swimming behavior (average speed) after exposure to the wastewater samples from all sites except for site E. Evidence from this study suggested that surface waters near beef cattle feed yards affected physiological responses in D. pulex and therefore may similarly affect organisms in the surrounding aquatic ecosystems.


Assuntos
Daphnia , Poluentes Químicos da Água , Agroquímicos , Animais , Bovinos , Ecossistema , Monitoramento Ambiental , Água , Poluentes Químicos da Água/toxicidade
2.
Sensors (Basel) ; 21(10)2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34068049

RESUMO

Density estimation of pelagic fish was performed by means of single beam echosounding in 17 lakes within a period of 34 years, from 1985 to 2018. Surveys were performed repeatedly (two to fourteen times) in five lakes. The density estimates ranged from 34 to 4720 fish/ha and were significantly correlated with total phosphorus concentration. The high density in relatively phosphorus rich lakes (TP > 10 µg/L) was comprised of small fish (<20 cm) and was partly due to the higher number of pelagic fish species. The number of pelagic species varied from one, Arctic charr, in the most elevated and oligotrophic lakes, and whitefish dominated in less elevated oligotrophic lakes. In lowland lakes characterized as mesotrophic or tending to mesotrophy, smelt, vendace, and two to three cyprinids comprised the pelagic fish stock. These fish species predate zooplankton effectively, and species composition and body size of planktonic cladocerans was affected by fish density. Large species of Daphnia were lacking in lakes with high fish density, and body size of present species, D. galeata, D. cristata, and Bosmina spp. were negatively correlated with pelagic fish density.


Assuntos
Peixes , Lagos , Animais , Daphnia , Noruega , Zooplâncton
3.
Ecol Lett ; 24(7): 1467-1473, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33963637

RESUMO

When prey experience size-based harvesting by predators, they are not only subject to selection due to larger individuals being preferentially harvested but also selection due to reductions in population density. Density-dependent selection represents one of the most basic interactions between ecology and evolution. Yet, the reduction in density associated with exploitation has not been tested as a possible driving force of observed evolutionary changes in populations harvested size-dependently. Using an artificial selection experiment with a mixture of Daphnia clones, we partition the evolutionary effects of size-based harvesting into the effects of removing large individuals and the effects of lowering the population density. We show that both size selection and density-dependent selection are significant drivers of life-history evolution. Importantly, these drivers affected different life-history traits with size-selective harvesting selecting for slower juvenile growth rates and a larger size at maturity, and low-density selecting for reduced reproductive output.


Assuntos
Evolução Biológica , Ecologia , Animais , Daphnia/genética , Densidade Demográfica , Reprodução
4.
Aquat Toxicol ; 235: 105836, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33932687

RESUMO

The importance of incorporating kinetic approaches in order to gain information on underlying physiological processes explaining species sensitivity to environmental stressors has been highlighted in recent years. Uranium is present in the aquatic environment worldwide due to naturally occurring and anthropogenic sources, posing a potential risk to freshwater taxa in contaminated areas. Although literature shows that organisms vary widely with respect to susceptibility to U, information on toxicokinetics that may explain the variation in toxicodynamic responses is scarce. In the present work, Daphnia magna were exposed to a range of environmentally relevant U concentrations (0 - 200 µg L-1) followed by a 48 h depuration phase to obtain information on toxicokinetic parameters and toxic responses. Results showed time-dependent and concentration-dependent uptake of U in daphnia (ku = 1.2 - 3.8 L g-1 day-1) with bioconcentration factors (BCFs) ranging from 1,641 - 5,204 (L kg-1), a high depuration rate constant (ke = 0.75 day-1), the majority of U tightly bound to the exoskeleton (~ 50 - 60%) and maternal transfer of U (1 - 7%). Effects on growth, survivorship and major ion homeostasis strongly correlated with exposure (external or internal) and toxicokinetic parameters (uptake rates, ku, BCF), indicating that uptake and internalization drives U toxicity responses in D. magna. Interference from U with ion uptake pathways and homeostasis was highlighted by the alteration in whole-body ion concentrations, their ionic ratios (e.g., Ca:Mg and Na:K) and the increased expression in some ion regulating genes. Together, this work adds to the limited data examining U kinetics in freshwater taxa and, in addition, provides perspective on factors influencing stress, toxicity and adaptive response to environmental contaminants such as uranium.


Assuntos
Daphnia/fisiologia , Urânio/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Transporte Biológico , Daphnia/metabolismo , Cinética , Alimentos Marinhos , Toxicocinética , Urânio/toxicidade
5.
Chemosphere ; 274: 129911, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33979935

RESUMO

Groundwater is an indispensable resource for humankind and sustainable biomes functioning. Anthropogenic disturbance threatens groundwater ecosystems globally, but to which extent groundwater organisms respond to stressors remains poorly understood. Groundwater animals are rare, with small populations, difficult to find and to breed in the lab, which poses a main challenge to the assessment of their responses to pollutants. Despite the difficulties, assessing the toxicity of a large spectrum of stressors to groundwater organisms is a priority to inform towards appropriate environmental protection of these ecosystems. We tested the sensitivity to CuSO4, diclofenac, and NaCl of a groundwater population of the copepod Diacyclops crassicaudis crassicaudis and compared its sensitivity with the model organism Daphnia magna. We ranked its sensitivity using a species sensitivity distribution (SSD) approach using the feasible data available for groundwater and surface crustaceans. Our results show that the most toxic compound was CuSO4 for which higher amount of data was recorded and wider variability in response was observed. It was followed by diclofenac, largely lacking data for groundwater-adapted organisms, and the least toxic compound was NaCl. The differential sensitivity between D. crassicaudis and D. magna was contaminant-dependent. As a general trend D. crassicaudis was always distributed in the upper part of the SSD curves together with other groundwater-adapted organisms. Our results highlight that the widespread groundwater populations of the D. crassicaudis species complex, which can be successfully breed in the lab, may provide a reasonable approach to assess the ecological effects of anthropogenic stressors in groundwater ecosystems.


Assuntos
Copépodes , Água Subterrânea , Poluentes Químicos da Água , Animais , Daphnia , Ecossistema , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
6.
Huan Jing Ke Xue ; 42(6): 3074-3083, 2021 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-34032108

RESUMO

Roxithromycin (ROX) is widespread in the water environment and has been reported to have ecotoxicological effects on aquatic organisms. To improve our understanding of these effects, we selected Daphnia magna as a test organism to study acute and chronic ROX toxicity on reproduction, growth, and antioxidant systems. The acute ROX toxicity was low, with 48 h-LC50 and 96h-LC50ROX values of 60.26 mg·L-1 and 39.81 mg·L-1, respectively. Furthermore, ROX concentrations of 0.5 µg·L-1 and 50 µg·L-1 significantly increased the frequency of egg laying, total number of eggs, and number of eggs per fetus. In the early exposure stages, ROX altered the sexual maturation time of Daphnia magna, affecting the frequency of egg laying and the number of eggs per fetus to cope with environmental stress. The intrinsic growth rate was also significantly increased by 50 µg·L-1 ROX. In both treatment groups, Daphnia magna had a shorter body length, abnormal heart rate, and inhibited swimming activity. Moreover, 50 µg·L-1 ROX inhibited the activities of POD, CAT, and GSH-Px by approximately 50% and induced MDA by more than 100%, resulting in the accumulation of reactive oxygen species in the body, which could potentially damage the cell membrane. In the 50 µg·L-1 ROX treatment, per 06 was up-regulated, enhancing the immune response of Daphnia magna. In contrast. gst and gst-theta were down-regulated, suggesting that ROX could weaken the detoxification effect of Daphnia magna. jhe, ecra, ecrb, rxr, vg1, vg2, and vit-2 were also down-regulated. ROX affected the secretion of juvenile and thyroid hormones, inhibiting the synthesis of vitellogenin. Finally, ROX also affected the growth and disturbed the population stability of Daphnia magna. This study provides a reference for the effects of ROX on the reproduction and growth of aquatic organisms and their responses at protein and gene levels.


Assuntos
Roxitromicina , Poluentes Químicos da Água , Animais , Daphnia , Oxirredução , Reprodução , Poluentes Químicos da Água/toxicidade
7.
J Hazard Mater ; 412: 125339, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33951881

RESUMO

This study assessed the reproductive toxicity of silver nanowires (AgNWs) in Daphnia magna over two consecutive generations. An acute immobilization test was conducted according to the ΟECD 202 guidelines. To perform reproductive toxicity tests in both F0 and F1 generations, the animals were exposed to different concentrations of AgNWs (0, 0.4, 2, 10, and 50 µg L-1) and pyriproxyfen (0.4 µg L-1), as a positive control, based on the ΟECD 211 principles. Overall, AgNWs were acutely toxic to D. magna with EC50 value of 0.063 mg L-1. Compared to the control groups, AgNWs disrupted reproductive performances of D. magna through increasing the egg development time and time to production of first brood as well as decreasing the total offspring production and molting frequency in both F0 and F1 generations. After exposure to AgNWs, the number of male neonates and non-reproductive females increased in the F0 generation, whereas just male neonates raised in the F1 generation. Moreover, AgNWs caused several congenital anomalies including underdeveloped antennae, 2nd antennae, malpighian tube, rostrum, sensory bristles, tail spine, and malformed eyes. Together, AgNWs could disrupt reproductive health of D. magna, and these types of bioperturbations could dramatically change the good health state of aquatic ecosystems.


Assuntos
Nanofios , Poluentes Químicos da Água , Animais , Daphnia , Ecossistema , Desenvolvimento Embrionário , Feminino , Humanos , Recém-Nascido , Masculino , Reprodução , Prata/toxicidade , Poluentes Químicos da Água/toxicidade
8.
Arch Environ Contam Toxicol ; 81(1): 46-57, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33864096

RESUMO

The present study investigates the toxicity of the herbicide tribenuron methyl (TBM) as an anthropogenic agent and ammonia as an abiotic factor on Daphnia magna at environmentally relevant concentrations. These stressors may coexist in surface waters in agricultural regions. To achieve this objective, D. magna were exposed to TBM at a nominal concentration of 0.81 µg/L in association with a low ammonia (LA) concentration of 0.65 mg/L and a high ammonia (HA) concentration of 1.61 mg/L in acute toxicity tests of 96-h duration and chronic toxicity tests of 21-day duration. The D. magna also were exposed to TBM, HA, and LA singly. The D. magna were analysed for various biomarkers of sublethal toxicity. Glutathione peroxidase (GPx), glutathione S-transferase (GST), cholinesterase (ChE) enzyme activities, and levels of thiobarbituric acid reactive substances (TBARS) and total protein were determined spectrophotometrically. Mitochondrial membrane potential (MMP) was analysed by microscopy with fluorescence staining. Cytochrome c and 5' AMP-activated protein kinase (AMPK) were analysed by Western blotting. Morphometric properties were examined microscopically. This is the first study in which AMPK, an indicator of intracellular energy, was measured in D. magna. GST and ChE enzyme activities and TBARS and total protein levels did not change during acute exposures (i.e., 96 h) in all treatments. GPx activity increased in D. magna from the HA + TBM treatment compared with single-exposure groups. The level of cytochrome c protein was elevated in D. magna from the LA and LA + TBM treatments. AMPK protein levels increased in all treatments with daphnids, except in the LA group. MMP was depolarised in D. magna from all treatments, whereas the most notable change was observed in HA + TBM mixture group in chronic exposures. The results show that GST and ChE may not be sensitive biomarkers for evaluating the sublethal toxic effects to D. magna exposed to environmentally relevant concentrations of ammonia and TBM. Acute and chronic exposure to ammonia and TBM probably caused an energetic crisis in D. magna. Therefore, AMPK and MMP are promising biomarkers for these toxicants.


Assuntos
Daphnia , Poluentes Químicos da Água , Amônia/toxicidade , Animais , Sulfonatos de Arila , Testes de Toxicidade Aguda , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
9.
Environ Sci Technol ; 55(9): 6150-6159, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33829772

RESUMO

Petroleum products and essential oils are produced and used in large amounts and are categorized as "Substances of Unknown or Variable composition, Complex reaction products or Biological materials (UVCBs)." These UVCBs are notorious difficult-to-test substances, since they are complex mixtures of hydrophobic and volatile compounds. This study introduces two passive dosing (PD) approaches for whole UVCB toxicity testing: (1) headspace PD applies the UVCB and purified lipid oil as a donor to control exposure via the headspace and (2) silicone rod PD applies UVCB-loaded silicone rods to control exposure via an aqueous test medium and headspace. Headspace gas chromatography-mass spectrometry measurements were used to cross-validate the approaches at the saturation level and to confirm exposure and maintain mixture composition at varying donor concentration levels. Both approaches were applied to whole-mixture toxicity tests of petroleum and essential oil UVCBs with daphnia and algae. Finally, the observed toxicity was linked to concentrations in the donor and in lipid membranes at equilibrium with the donors. Dose-response curves were similar across the dosing approaches and tested species for petroleum products but differed by an order of magnitude between essential oils and PD systems. All observed toxic effects were consistent with baseline toxicity, and no excess mixture toxicity was observed.


Assuntos
Óleos Voláteis , Petróleo , Animais , Daphnia , Interações Hidrofóbicas e Hidrofílicas , Óleos Voláteis/toxicidade , Petróleo/toxicidade , Testes de Toxicidade
10.
Water Res ; 197: 117109, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33857893

RESUMO

Tracer tests represent a well-established method for delineating key environmental processes in various media and engineered systems. Tracers like Rhodamine B and WT are frequently applied due to their strong fluorescence even at low concentrations.. However, due to a lack of ecotoxicological data, limit values for these tracers cannot be determined. This study fills this critical data gap by providing ecotoxicity data for Rhodamine B and WT using a battery of short-term standardized tests, including growth rate inhibition tests with algae (Raphidocelis subcapitata) and lethality tests using crustaceans (Daphnia magna) and zebrafish (Danio rerio) embryos, and estimating EQS for surface water. For Rhodamine B, the effective and lethal concentration (EC50 and LC50) -causing 50% toxicity were in the range of 14-24 mg/L. For Rhodamine WT, no statistically significant effects were observed (p<0.05) at the tsted concentrations (up to 91, 100 and 200 mg/L for algae, crustaceans and fish embryos, respectively). Thus for all tested organisms, Rhodamine B was more toxic than Rhodamine WT (more than 14 times more toxic for R. subcapitata, 5.6 times for D. magna, 15 times for D. rerio embryos,based on EC10 and LC10 values). These results signify that read-across assessments using ecotoxicity data obtained with Rhodamine B is not advisable for estimating the ecotoxicity of Rhodamine WT. The annual-average quality standard (AA-QS) and maximum allowable concentration quality standard (MAC-QS) for Rhodamine B were found to be 14 and 140 µg/L, respectively. For Rhodamine WT, the corresponding values were estimated to >91 µg/L (AA-QS) and >910 µg/L (MAC-QS). Hence, concentrations below 140 µg/L or 910 µg/L for Rhodamine B and WT, respectively, are not expected to pose a risk to aquatic freshwater life in the case of intermittent discharges, e.g. tracer experiments released in streams.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Animais , Daphnia , Rodaminas , Poluentes Químicos da Água/toxicidade
11.
Environ Monit Assess ; 193(5): 293, 2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33893596

RESUMO

Intensive livestock farming has increased the use of veterinary pharmaceuticals in many developing countries, and this is considered a significant concern to the freshwater ecosystem. However, the information on the potential acute toxicity of piggery effluent waste and the veterinary pharmaceutical effluent discharged into the aquatic environment is limited. This study assessed the adverse effect of a piggery effluent and the cocktail mixtures of high- and low-level doses of three frequently occurring veterinary pharmaceuticals (tetracycline (TETR), ivermectin (IVER), and salicylic acid (SALA)) on freshwater organisms using three representative freshwater biotests organisms: Pseudokirchneriella subcapitata (P. subcapitata), Daphnia magna (D. magna), and Tetrahymena thermophila (T. thermophila). The freshwater organism test results showed that the 24-h and 48-h EC50 algal toxicity to P. subcapitata exposed to 10% unfiltered piggery effluent were 25.6 and 49.3% respectively while the 24-h LC50 value to Cladocera, D. magna exposed to unfiltered piggery effluent was 23.2 (17.7-30.4)%. The 24-h EC50 protozoan toxicity to T. thermophila exposed to 1% HLD veterinary pharmaceuticals was 0.014 µg/L. Thus, the study established the different sensitivities of freshwater organisms to various percentage levels of piggery effluent and high- and low-level doses of veterinary pharmaceutical. The piggery effluent and the pharmaceutical cocktail mixtures have potential toxicological effects on the freshwater ecosystem.


Assuntos
Drogas Veterinárias , Poluentes Químicos da Água , Animais , Daphnia , Ecossistema , Monitoramento Ambiental , Água Doce , Drogas Veterinárias/toxicidade , Poluentes Químicos da Água/toxicidade
12.
Int J Mol Sci ; 22(9)2021 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-33921959

RESUMO

Chloroxylenol (PCMX) is applied as a preservative and disinfectant in personal care products, currently recommended for use to inactivate the SARS-CoV-2 virus. Its intensive application leads to the release of PCMX into the environment, which can have a harmful impact on aquatic and soil biotas. The aim of this study was to assess the mechanism of chloroxylenol biodegradation by the fungal strains Cunninghamella elegans IM 1785/21GP and Trametes versicolor IM 373, and investigate the ecotoxicity of emerging by-products. The residues of PCMX and formed metabolites were analysed using GC-MS. The elimination of PCMX in the cultures of tested microorganisms was above 70%. Five fungal by-products were detected for the first time. Identified intermediates were performed by dechlorination, hydroxylation, and oxidation reactions catalysed by cytochrome P450 enzymes and laccase. A real-time quantitative PCR analysis confirmed an increase in CYP450 genes expression in C. elegans cells. In the case of T. versicolor, spectrophotometric measurement of the oxidation of 2,20-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) showed a significant rise in laccase activity during PCMX elimination. Furthermore, with the use of bioindicators from different ecosystems (Daphtoxkit F and Phytotoxkit), it was revealed that the biodegradation process of PCMX had a detoxifying nature.


Assuntos
Cunninghamella/metabolismo , Trametes/metabolismo , Xilenos/metabolismo , Animais , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Daphnia/efeitos dos fármacos , Daphnia/fisiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Regulação da Expressão Gênica , Lacase/metabolismo , Oxirredução , Testes de Toxicidade , Xilenos/análise , Xilenos/farmacologia
13.
Sci Total Environ ; 784: 147113, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-33892323

RESUMO

The presence of sex steroid hormones in aquatic ecosystems is of rapidly growing concern worldwide since they can affect the different non-target species including cladocerans. Although data are available on the effects of estrogens on the well-established ecotoxicological model organism Daphnia magna, the molecular or behavioural alterations induced by environmentally relevant concentrations (from a few ng L-1 to a few hundred ng L-1 in average) of progestogens have not been investigated on this species. In the present study, we exposed neonates of D. magna to relevant equi-concentrations (1, 10, 100, 500 ng L-1) of mixtures of four progestogens (progesterone, drospirenone, gestodene, levonorgestrel) in short-term (6 days) and long-term (21 days) experiments. Significant alterations were observed at the molecular, cellular, and individual levels. During the short-term exposure, all of the mixtures increased the gene expression of glutathione S-transferase (GST) detoxification enzyme, moreover, the activity of GST was also significantly increased at the concentrations of 10, 100, and 500 ng L-1. In long-term exposure, the number of days until production of the first eggs was reduced at the 10 ng L-1 concentration compared to control, furthermore, the maximum egg number per individual increased at the concentrations of 1 and 10 ng L-1. Based on the authors' best knowledge, this is the first study to investigate the effects of progestogens in mixtures and at environmentally relevant concentrations on D. magna. Our findings contribute to the understanding of the possible physiological effects of human progestogens. Future research should be aimed at understanding the potential mechanisms (e.g., perception) underlying the changes induced by progestogens.


Assuntos
Cladóceros , Poluentes Químicos da Água , Animais , Daphnia , Ecossistema , Humanos , Recém-Nascido , Progestinas/toxicidade , Reprodução , Poluentes Químicos da Água/toxicidade
14.
Sci Total Environ ; 784: 147082, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-33894603

RESUMO

In many ecosystems, the zooplankton community has been pressured simultaneously by microplastic pollution and alterations resulting from global climate changes. The potential influence of light intensity rise (from 10,830 lx to 26,000 lx) and water temperature rise (from 20 °C to 25 °C) on the long term-toxicity of microplastics (MPs) to Daphnia magna were investigated. Three 21-day laboratory bioassays with model MPs (1-5 µm diameter) were carried out at (i) 20 °C/10830 lx, (ii) 20 °C/26000 lx, and (iii) 25 °C/10830 lx. In each bioassay, one control (no MPs) and three MP concentrations (0.04, 0.09, 0.19 mg/L) were tested. In all the bioassays, MPs caused parental and juvenile mortality, and reduced the somatic growth, reproduction and population growth rate. The MP EC50s on living offspring (95% confidence interval within brackets) were 0.146 mg/L (0.142-0.151 mg/L) at 20 °C/10830 lx, 0.102 mg/L (0.099-0.105 mg/L) at 20 °C/26000 lx, and 0.101 mg/L (0.098-0.104 mg/L) at 25 °C/10830 lx. Relatively to the respective control group, 0.19 mg/L of MPs decreased the mean of the population growth rate by 27% at 20 °C/10830 lx, 38% at 20 °C/26000 lx and 59% at 25 °C/10830 lx. Based on the population growth rate and in relation to 20 °C/10830 lx (control, no MPs), the interaction between increased light intensity (26,000 lx) and MPs was synergism (at all the MP concentrations tested). The interaction between water temperature rise (25 °C) and MPs was antagonism at 0.04 mg/L of MPs and synergism at 0.09 and 0.19 mg/L of MPs. In the present scenario of climate changes and global MP pollution such findings raise high concern because zooplankton communities are crucial for aquatic biodiversity conservation, ecosystem functioning and services provided to humans. Further studies on the combined effects of MPs, other common pollutants, and alterations due to climate changes are needed.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Daphnia , Ecossistema , Humanos , Plásticos , Crescimento Demográfico , Reprodução , Temperatura , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
15.
Nat Commun ; 12(1): 1945, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782425

RESUMO

Exploring the capability of organisms to cope with human-caused environmental change is crucial for assessing the risk of extinction and biodiversity loss. We study the consequences of changing nutrient pollution for the freshwater keystone grazer, Daphnia, in a large lake with a well-documented history of eutrophication and oligotrophication. Experiments using decades-old genotypes resurrected from the sediment egg bank revealed that nutrient enrichment in the middle of the 20th century, resulting in the proliferation of harmful cyanobacteria, led to the rapid evolution of grazer resistance to cyanobacteria. We show here that the subsequent reduction in nutrient input, accompanied by a decrease in cyanobacteria, resulted in the re-emergence of highly susceptible Daphnia genotypes. Expression and subsequent loss of grazer resistance occurred at high evolutionary rates, suggesting opposing selection and that maintaining resistance was costly. We provide a rare example of reversed evolution of a fitness-relevant trait in response to relaxed selection.


Assuntos
Coevolução Biológica , Cianobactérias/patogenicidade , Daphnia/genética , Aptidão Genética , Poluição da Água/análise , Animais , Cianobactérias/fisiologia , Daphnia/crescimento & desenvolvimento , Daphnia/metabolismo , Europa (Continente) , Eutrofização , Genótipo , Humanos , Lagos/química , Fenótipo , Característica Quantitativa Herdável , Seleção Genética
16.
Sci Total Environ ; 764: 142902, 2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33757253

RESUMO

To avoid potential risks of biofuels on the environment and human, ecotoxicity investigation should be integrated into the early design stage for promising biofuel candidates. In the present study, a green toxicology testing strategy combining experimental bioassays with in silico tools was established to investigate the potential ecotoxicity of biofuel candidates. Experimental results obtained from the acute immobilisation test, the fish embryo acute toxicity test and the in vitro micronucleus assay (Chinese hamster lung fibroblast cell line V79) were compared with model prediction results by ECOSAR and OECD QSAR Toolbox. Both our experimental and model prediction results showed that 1-Octanol (1-Oct) and Di-n-butyl ether (DNBE) were the most toxic to Daphnia magna and zebrafish among all the biofuel candidates we investigated, while Methyl ethyl ketone (MEK), Dimethoxymethane (DMM) and Diethoxymethane (DEM) were the least toxic. Moreover, both in vitro micronucleus assay and OECD QSAR Toolbox evaluation suggested that the metabolites present higher genotoxicity than biofuel candidates themselves. Overall, our results proved that this green toxicology testing strategy is a useful tool for assessing ecotoxicity of biofuel candidates.


Assuntos
Biocombustíveis , Poluentes Químicos da Água , Animais , Biocombustíveis/toxicidade , Linhagem Celular , Cricetinae , Daphnia , Humanos , Testes de Toxicidade Aguda , Peixe-Zebra
17.
Ecotoxicol Environ Saf ; 215: 112151, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33743402

RESUMO

The Water Framework Directive (WFD) was adopted in 2000 and is a common framework for water policy, management and protection in Europe. The WFD assesses specific parameters; however, it ignores indicators of ecosystem functioning and sub-individual performance. Reservoirs are strongly influenced by anthropogenic activities that promote their imbalance. Bioassays and biomarkers are useful tools to link the chemical, ecological and toxicological assessments in water quality assessments. These approaches can be complementary to WFD methodologies, allowing the detection of impacts on the ecosystem. This study evaluated if the biochemical parameters can improve the sensitivity of the biomonitoring strategy using bioassays with the standard species Daphnia magna, in the assessment of the ecological quality of water reservoirs. To this end, water samples of Portuguese reservoirs were analysed in three sampling periods (Autumn 2018 and Spring, Autumn 2019). In parallel, a physicochemical characterization of waters was performed. D. magna feeding rate assays were performed for 24 h. After exposure, metabolism, oxidative stress and lipid peroxidation biomarkers were evaluated. Feeding rate assays showed sensitivity to different reservoirs. Biomarkers showed a higher sensitivity and can therefore improve the sensitivity of the biomonitoring strategy using bioassays. Bioassays and biomarkers approach allowed to highlight potential sources of stress, more related to the quality of the seston than to chemical contamination. This work highlights the complementarity between bioassays and biomarkers to identify ecotoxicological effects of surface waters, and can be extremely useful, especially in cases where the biotic indices are difficult to establish, such as reservoirs.


Assuntos
Bioensaio , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Animais , Monitoramento Biológico , Daphnia/efeitos dos fármacos , Ecossistema , Ecotoxicologia , Europa (Continente) , Padrões de Referência , Estações do Ano , Qualidade da Água
18.
Environ Pollut ; 278: 116918, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33743270

RESUMO

Many prey organisms adaptively respond to predation risk by inducible defenses with underlying tradeoffs in resource allocation. Cyanobacterial blooms expose zooplankton to poor food conditions, affecting the herbivores' fitness. Given the interferences on resources allocation and life history traits, poor-quality cyanobacteria are predicted to affect the adaptive predator-induced responses in zooplankton. Here, we exposed two clones (i.e., clones SH and ZJ) of the cladoceran Daphnia mitsukuri to different combinations of fish predation cues and diets containing toxic Microcystis aeruginosa (0%-30%). D. mitsukuri matured at a small size and had elongated relative tail spine as adaptive responses to fish cues. Despite the comparable tail spine defense, fish cue-induced changes in growth and reproduction in the clone SH were more pronounced than those in the clone ZJ under no M. aeruginosa. Animals accumulated microcystin in the whole body with increasing abundance of M. aeruginosa. However, the inducible enhanced tail spine allometry was not affected, resulting in unchanged tail spine defense by Daphnia under all M. aeruginosa treatments. By contrast, M. aeruginosa remarkably decreased the adaptive maturation size and the offspring number in all animals. However, the inducible reproductive effort tended to increase or remain unchanged depending on clones associated with the constant or decreased responses of the somatic growth effort under increasing M. aeruginosa. Our results suggested that toxic M. aeruginosa did not alter the resource allocation to antipredator morphological defense but affected the somatic growth and reproduction in D. mitsukuri under fish cues. The present study highlights the different effects of toxic cyanobacteria on adaptive predator-induced responses in zooplankton, promoting the understanding for the morphological defense-mediated predator-prey interactions in eutrophic environments.


Assuntos
Microcystis , Animais , Sinais (Psicologia) , Daphnia , Comportamento Predatório , Alocação de Recursos
19.
Environ Sci Technol ; 55(8): 5143-5151, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33726495

RESUMO

Widely applied silver nanoparticles (AgNPs) can have potentially detrimental impacts on aquatic organisms. Unicellular algae as primary producers can interact with AgNPs and initiate their transfer along food chains. Herein, we demonstrate that AgNPs were internalized in a freshwater phytoplankton species Chlamydomonas reinhardtii, but the entrance pathways varied with their surface coatings. Citrate-coated AgNPs (Cit-AgNPs) were internalized mainly through the apical zone of the cell near the flagella, whereas the aggregation-induced emission fluorogen (AIEgen)-coated AgNPs (AIE-AgNPs) were internalized through endocytosis. The internalized AgNPs were dissolved intracellularly and the released Ag+ was distributed heterogeneously in the cytoplasm, in contrast to the directly accumulated Ag+ which displayed a diffuse cytoplasmic distribution pattern. We then further visualized and quantified the trophic transfer of AgNPs from the alga C. reinhardtii to the zooplanktonic species Daphnia magna. Both trophically transferred Ag+ and AgNPs were concentrated in the gut regions of D. magna as a result of the direct ingestion of food particles. After ingestion, about 95% of the trophically transferred Ag+ was eliminated. Retention of AIE-AgNPs by daphnids was relatively higher than that of Cit-AgNPs due to their lower dissolution of Ag+. The present study provides direct evidence for the internalization of AgNPs in unicellular algae and demonstrates that the biological transport of trophically transferred of AgNPs is related to the different surface coatings of NPs.


Assuntos
Nanopartículas Metálicas , Poluentes Químicos da Água , Animais , Transporte Biológico , Daphnia , Prata , Nitrato de Prata
20.
BMC Bioinformatics ; 22(1): 151, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33761866

RESUMO

BACKGROUND: A number of predictive models for aquatic toxicity are available, however, the accuracy and extent of easy to use of these in silico tools in risk assessment still need further studied. This study evaluated the performance of seven in silico tools to daphnia and fish: ECOSAR, T.E.S.T., Danish QSAR Database, VEGA, KATE, Read Across and Trent Analysis. 37 Priority Controlled Chemicals in China (PCCs) and 92 New Chemicals (NCs) were used as validation dataset. RESULTS: In the quantitative evaluation to PCCs with the criteria of 10-fold difference between experimental value and estimated value, the accuracies of VEGA is the highest among all of the models, both in prediction of daphnia and fish acute toxicity, with accuracies of 100% and 90% after considering AD, respectively. The performance of KATE, ECOSAR and T.E.S.T. is similar, with accuracies are slightly lower than VEGA. The accuracy of Danish Q.D. is the lowest among the above tools with which QSAR is the main mechanism. The performance of Read Across and Trent Analysis is lowest among all of the tested in silico tools. The predictive ability of models to NCs was lower than that of PCCs possibly because never appeared in training set of the models, and ECOSAR perform best than other in silico tools. CONCLUSION: QSAR based in silico tools had the greater prediction accuracy than category approach (Read Across and Trent Analysis) in predicting the acute toxicity of daphnia and fish. Category approach (Read Across and Trent Analysis) requires expert knowledge to be utilized effectively. ECOSAR performs well in both PCCs and NCs, and the application shoud be promoted in both risk assessment and priority activities. We suggest that distribution of multiple data and water solubility should be considered when developing in silico models. Both more intelligent in silico tools and testing are necessary to identify hazards of Chemicals.


Assuntos
Daphnia , Relação Quantitativa Estrutura-Atividade , Poluentes Químicos da Água , Animais , China , Simulação por Computador , Poluentes Químicos da Água/toxicidade
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