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Ecotoxicology

Current research reports and chronological list of recent articles..




Ecotoxicology is an international scientific journal devoted to the publication of fundamental research on the effects of toxic chemicals on populations, communities and terrestrial, freshwater and marine ecosystems.

The publisher is Springer. The copyright and publishing rights of specialized products listed below are in this publishing house. This is also responsible for the content shown.

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Additional research articles see Current Chemistry Research Articles. Magazines with similar content (environmental chemistry):

 - Atmospheric Chemistry.

 - Chemosphere.

 - Environmental Chemistry.

 - Environmental Chemistry Letters.

 - Environmental Monitoring.

 - Environmental Science and Technology.

 - Environmental Toxicology.



Ecotoxicology - Abstracts



Analysis of the miRNA expression profile of laboratory red crucian carp under low-dose caesium-137 irradiation

Abstract

Radiation can cause the differential expression of biological miRNA molecules. This research was based on the development of the laboratory red crucian carp (LRCC) to explore the feasibility of its application in the detection of low-dose ionizing radiation-induced biological damage in aquatic environments and the development of related molecular markers. Adult LRCC were irradiated with caesium-137 at 0.3 Gy, while RNA-seq and bioinformatics techniques were used to identify miRNAs that were differentially expressed relative to their levels in the nonirradiation group. Analysis of liver sections showed that liver cells in the radiation group showed nuclear pyknosis. In this study, 34 miRNAs differentially expressed in the liver of LRCC after irradiation were identified, among which seven were new crucian carp miRNAs; a total of 632 target genes were predicted in the prediction analysis. The results of comprehensive GO enrichment and KEGG pathway analyses showed that these target genes were mainly involved in energy transfer and material catabolism, especially malonyl-CoA biosynthesis, acetyl-CoA carboxylase activity, fatty acid biosynthesis and metabolism, and pyruvate metabolism; in addition, the AMPK signalling pathway was the most active pathway. This study shows that the LRCC is sensitive to radiation, or can be used as a candidate experimental animal to study the biological effects of radiation, and the screened miRNA can be used as a pre-selected biomarker for radiation damage detection and radiation biological environmental monitoring.

Clinical Trials Registration

None.


Datum: 01.10.2022


Physiological and microbiological hormesis in sedge Eleocharis palustris induced by crude oil in phytoremediation of flooded clay soil

Abstract

Soil contamination with petroleum hydrocarbons affects plants and rhizospheric microorganisms. Microbial activity participates in important biochemical processes that stimulate, together with plants, the modification of toxic compounds for organisms. A nine-month experiment was set up to study the effect over time of oil on plant height (cm), formation of new plants, plant matter production (gravimetry), and population of rhizospheric microorganisms (serial dilution) in the sedge Eleocharis palustris. Removal of total petroleum hydrocarbons (soxhlet and gravimetry) from the soil was also evaluated. The means of the evaluated variables registered significant statistical differences (Duncan, p < 0.05) regarding the age of the plant and the amount of crude oil. There was a high correlation between oil and plant height (0.848) and with new plants (0.994). 60 mg oil dose promoted the greatest statistical difference in the amounts of roots and plant biomass (p < 0.05). E. palustris exposed to 60 and 75 mg of oil stimulated high densities of microalgae, actinomycetes, fungi, hydrocarbonoclastic bacteria and Pseudomonas spp; the overall ratio was 2:1 relative to natural attenuation. Plant and microorganism variables evaluated registered physiological and microbiological hormetic indices ≥1, showing a positive linear relationship. Natural attenuation was more efficient in removing crude oil. We conclude that E. palustris is tolerant to oil exposure. It is suggested to combine it with natural attenuation for the optimization of soils contaminated with crude oil.


Datum: 01.10.2022


Does persistent organic pollutant PFOS (perfluorooctane sulfonate) negative impacts on the aquatic invertebrate organism, Astacus leptodactylus [Eschscholtz, 1823]

Abstract

Highly persistent perfluorooctane sulfonate (PFOS) is an industrial fluorinated organic chemical with significant bioaccumulation and biomagnification properties. The purpose of this study was to determine the toxic effects of sublethal PFOS on the aquatic invertebrate organism, narrow-clawed crayfish [Astacus leptodactylus Eschscholtz, 1823]. The 96 h LC50 value was determined as 48.81 mg/L (34.19–63.68 mg/L) with probit analysis. The sublethal experimental design was formed into four groups solvent control (DMSO, dimethyl sulphoxide), non-treated control group, and 1/10 (5 mg/L) and 1/100 (0.5 mg/L) of 96 h LC50 of PFOS, and crayfish were exposed for 48 h, 7 d, and 21 d under laboratory conditions. Total haemocyte counts (THCs) decreased, while the haemolymph total antioxidant status (TAS) values increased (p < 0.05) after exposure to 0.5 and 5 mg/L PFOS for 48 h, 7 d, and 21 d. Haemolymph total oxidative stress (TOS) levels significantly increased at 5 mg/L PFOS concentration (p < 0.05). Catalase (CAT) activities increased at both concentrations after 48 h and 7 d and then returned to control levels after 21 d; whereas superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities did not change in muscle tissue (p > 0.05). GPX and CAT activities decreased, but SOD activity increased in hepatopancreas tissue (p < 0.05). SOD activity at both concentrations and CAT activity at 5 mg/L PFOS exposure decreased in gill tissue, while GPX activity increased at both concentrations of 48 h and 7 d and returned to control values on day 21 of exposure. Histopathological alterations were detected in hepatopancreas and gill tissues. Lamellar deformations, epithelial hyperplasia, and haemocytic infiltrations were observed in the gill tissues, whereas tubular degeneration, tubule loss, necrosis, and lesions in the hepatopancreas tissues were the major recorded alterations. As a result, the sublethal concentrations of PFOS have toxic effects on crayfish and histologically cause tissue damage. Our findings also support a better understanding of the early toxicological effects of PFOS in freshwater ecosystems. Also, it could be concluded that A. leptodactylus is a reliable model for examining histopathological alterations and differences in enzyme activities together with the haemolymph findings in toxicology studies amid aquatic species.


Datum: 01.10.2022


Identification and quantitation of the novel insecticide sulfoxaflor and its metabolites in floral nectar from Salvia splendens Ker Gawl. (Lamiaceae)

Abstract

Sulfoxaflor is a new systemic insecticide developed as a replacement for older neonicotinoids which are known to be toxic to pollinators. However, its metabolism in nectar and effect on nectar biosynthesis have not been investigated. After soil and foliar application, sulfoxaflor and its main metabolites in soil, leaf and Salvia splendens nectar, were measured by liquid chromatography coupled with triple quadrupole mass spectrometer (LC-MS/MS). The chemical composition between the clean and sulfoxaflor spiked nectar were also compared. The activities of two possible sulfoxaflor detoxifying enzymes in S. splendens nectar, nitrile hydratase and glutathione-s-transferase, were measured by LC-MS and spectrophotometry. S. splendens nectar proteome was investigated by high-resolution orbitrap-based MS/MS to screen for sulfoxaflor detoxifying relevant proteins. S. splendens could absorb sulfoxaflor through root or leaf surface and secrete a proportion of sulfoxaflor along with its metabolites into the nectar. After soil application, sulfoxaflor’s low toxic metabolite X11719474 was dominant in the nectar and reached an average concentration of 8905 ppb. However, after foliar application, sulfoxaflor was dominant over its metabolites in the nectar. S. splendens nectar has no nitrile hydratase and glutathione-s-transferase activity and none of the 106 proteins identified in the nectar were predicted to function in detoxifying sulfoxaflor. Soil and foliar sulfoxaflor application can result in different profiles of sulfoxaflor and its metabolites presented in the nectar. However, sulfoxaflor had no effects on S. splendens nectar secretion and chemical composition and cannot be directly detoxified by components in the nectar.


Datum: 01.10.2022


Same sensitivity with shorter exposure: behavior as an appropriate parameter to assess metal toxicity

Abstract

The exposure of animals to toxicants may cause a depletion in the energy uptake, which compromises reproduction and growth. Although both parameters are ecologically relevant, they usually need long-term bioassays. This is a handicap for the availability of toxicological data for environmental risk assessment. Short-term bioassays conducted with environmental concentrations, and using relevant ecological parameters sensitive to short-term exposures, such as behavior, could be a good alternative. Therefore, to include this parameter in the risk assessment procedures, it is relevant the comparison of its sensitivity with that of growth and reproduction bioassays. The study aim was the assessment of differences between endpoints based on mortality, behaviour, reproduction, and growth for the toxicity of metals on aquatic animals. We used the ECOTOX database to gather data to construct chemical toxicity distribution (CTD) curves. The mean concentrations, the mean exposure time, and the ratio between the mean concentration and the exposure time were compared among endpoints. Our results showed that behavioral, growth, and reproduction bioassays presented similar sensitivity. The shortest exposure was found in behavioral and reproduction bioassays. In general, the amount of toxicant used per time was lower in growth and reproduction bioassays than in behavioral and mortality bioassays. We can conclude that, for metal toxicity, behavioral bioassays are less time-consuming than growth bioassays. As the sensitivity of behavior was similar to that of growth and reproduction, this endpoint could be a better alternative to longer bioassays.


Datum: 01.10.2022


Effects of glyphosate on zebrafish: a systematic review and meta-analysis

Abstract

Glyphosate herbicide is widely used in worldwide crop production. Consequently, its active ingredient, surfactants, and adjuvants commonly reach the aquatic ecosystem, thereby harming the biota. An investigation into how this herbicide affects aquatic species is important, especially in fish, as they have the ability to absorb and concentrate toxins. We aimed to evaluate the effects of glyphosate on the embryonic, larval and adult stages of zebrafish (Danio rerio), an appreciable organismal model. In this sense, we performed a meta-analysis using published articles from online databases (PubMed and ScienceDirect), which covered studies published until 2022. From a massive compilation of studies evaluating the effects of active substance glyphosate and Glyphosate-Based Herbicides (GBH) on zebrafish, we selected 36 studies used in downstream analyses. Overall, we report that glyphosate affects developmental stages and demonstrates toxicity and damage in zebrafish. We observed that embryos exposed to glyphosate exhibit increased mortality. There was also an increase in the number of morphological abnormalities related to yolk sac oedema, pericardial oedema, spinal curvature and body malformations, and a decrease in body size was observed. Furthermore, there was a decrease in the number of beats. The biochemical results demonstrated an increase in reactive oxygen species and antioxidant capacity against peroxyl radicals in the gills. The literature shows that glyphosate decreased the distance covered and the mean speed of the animals and increased the number of rotations. We concluded that glyphosate causes damage in the embryonic, larval and adult stages of this species. These results are valid for zebrafish and can be applied to other freshwater fish species.

Graphical abstract


Datum: 01.10.2022


Proline-mediated modulation on DNA repair pathway in rice seedlings under chromium stress by integrating gene chip and co-expression network analysis

Abstract

Chromium (Cr) stress can cause oxidative burst to plants. Application of exogenous proline (Pro) is one of the most effective approaches to improve the tolerance of plants to Cr stress. In this study, we integrated the data of gene chip with co-expression network analysis to identify the key pathways involved in the DNA repair processes in rice seedlings under Cr(VI) stress. Based on KEGG pathway analysis, 158 genes identified are activated in five different types of DNA repair pathways, namely base excision repair (BER, 20 genes), mismatch repair (MMR, 30 genes), nonhomologous end joining (NHEJ, 8 genes), nucleotide excision repair (NER, 56 genes) and homologous recombination (HR, 44 genes). Co-expression network analysis showed that genes activated in DNA repair pathways were categorized into six different modules, wherein Module 1 (45.36%), Module 2 (27.84%) and Module 3 (19.59%) carried more weight than others. Integrating the data of gene chip and co-expression network analysis indicated that coordinated actions of HR and NER pathways are mainly associated with DNA repair processes in Cr(VI)-treated rice seedlings supplied with exogenous Pro. OsCSB, OsXPG, OsBRIP1, OsRAD51C, OsRAD51A2, OsRPA, OsTOPBP1C, OsTOP3, and OsXRCC3 activated in the HR pathway had a stronger impact on repairing DNA damage induced by Cr(VI) stress in rice seedlings supplied with exogenous Pro, while OsXPB1, OsTTDA2, OsTFIIH1, OsXPC, OsRAD23, OsDSS1, and OsRPA located at the NER pathway showed more contribution to repairing DNA damage than others.


Datum: 01.10.2022


Tebufenozide has limited direct effects on simulated aquatic communities

Abstract

The use of insecticides to control undesirable pest species in forestry has undergone a shift from broad spectrum to narrow spectrum insecticides to reduce the risk of effects on non-target species. However, there is still risk of direct effects on non-target species as some insecticides function as hormone mimics, or through indirect pathways as the insecticide is broken down in the environment. Tebufenozide, an ecdysone hormone mimic, is the active ingredient in insecticides used in a variety of large scale pest control programs. An oft cited reason for the safety of Tebufenozide is that it is rapidly broken down in the environment by microbes. We investigated the potential non-target effects of two Tebufenozide formulations used in Canada, Mimic 240LV and Limit 240, on aquatic communities using an outdoor mesocosm experiment. We focus on direct effects on amphibian larvae (wood frog, Rana sylvaticus), zooplankton communities, and effects on biofilm and phytoplanktonic microbial communities that could arise from either direct toxicity, or from breaking down the insecticide as a nutrient and/or carbon source. There was limited evidence for direct effects on amphibian larvae or zooplankton communities. There were small but non-significant shifts in biofilm microbial communities responsible for nutrient cycling. Beta diversity in the plankton community was slightly higher among tanks treated with insecticide indicating a community dispersion/disbiosis effect. Overall, we found limited evidence of negative effects, however, subtle changes to microbial communities did occur and could indicate changes to ecosystem function.


Datum: 01.10.2022


Determination of stomatic density, index, and area as exposition biomarkers of pollution in Deschampsia antárctica Desv. (Poaceae)

Abstract

Until not so long ago, Antarctica was considered to be a polar region practically pristine. The Antarctic Peninsula has the highest concentration of scientific stations from different countries. Anthropogenic activity has caused alterations in the Antarctic ecosystems directly affecting terrestrial vegetation. This fact requires the finding of biomarkers in native plants to estimate the effects of human impact. Deschampsia antarctica Desv. (Poaceae) is the unique native grass described so far for Antarctica and was used for multiple investigations. In this study, plants were collected on Carlini scientific station, 25 de Mayo (King George) Island, Potter Peninsula, South Shetland Islands. Thus, the main objective planned consists of the evaluation of leaf stomata-related parameters as pollution biomarkers. The results of the stomatic index (SI), density (SD), and area (SA) were shown at sites with different levels of human impact (close and far away from the scientific station). It was found that the correlation between SD and SI, on the adaxial side of the leaves, resulted in a good biomarker for estimating the degree of anthropogenic impact in each studied area.

Graphical abstract


Datum: 01.10.2022


Assessment of the toxicity of weathered petroleum hydrocarbon impacted soils to native plants from a site in the Canadian Subarctic

Abstract

Remedial guidelines for petroleum hydrocarbons (PHCs) in soil aid in the mitigation of risks to human health and the environmental. However, some remediation guidelines may overestimate the potential for adverse effects to native plant species, contributing to unnecessary remedial efforts in attempts to meet the guidelines. At sites where PHC-contaminated soils undergo weathering, some PHCs may persist but with decreased bioavailability to organisms. In this study, the toxicity of both coarse and fine-grained subarctic soils, contaminated with weathered PHCs were assessed using five native plant species (Picea mariana, Achillea millefolium, Alnus viridis, Elymus trachycaulus and Salix bebbiana). Soil toxicity tests were conducted in a growth chamber with parameters set to simulate the site’s subarctic climate conditions. Reference toxicant tests using boric acid were conducted to provide confidence in the interpretation of the results for the PHC-contaminated soils, and also provide new information on the sensitivities of the four boreal species to boric acid. All plants exhibited reduced growth and germination rates as boric acid concentrations increased. Despite exceeding the Canada-wide standard guidelines for Fraction 3 PHCs, field-collected contaminated soils had no significant negative impacts on the growth (i.e., length, dry weight and emergence) of any of the plant species tested.


Datum: 01.10.2022


Metformin-induced alterations in gills of the freshwater fish Astyanax lacustris (Lütken, 1875) detected by histological and scanning electron microscopy

Abstract

The antidiabetic drug metformin is widely prescribed and found in different concentrations in the environment around the world, raising concern about potential impacts on aquatic life. Analyses of the effects of exposure of biological models to aquatic contaminants are important for assessing pollution effects on fish health. The gills of fishes represent primary targets of disturbance by pollutants, mainly because of the large surface of the respiratory epithelium and the high perfusion rate, which both help the entry of pollutants into this tissue. In this context, the aim of this work was to use gill histological analyses biomarkers to evaluate the toxicity of metformin on aquatic environmental systems, by means of chronic exposure for 90 days of Astyanax lacustris (lambari), an ecologically important neotropical species that can be used as an environmental bioindicator. Histopathological analyses were performed using Light and Scanning Electron Microscopy. The main changes were lamellar fusion, telangiectasia hyperplasia and disappearance of microridges. The morphological changes observed possibly interfere with the gill physiology, indicating an unfavorable situation to the presence of metformin in the water, pointing to a concern that metformin may pose a risk to Astyanax lacustris and likely to other fish species, compromising the dynamics of the aquatic ecosystem as a whole.

Graphical abstract


Datum: 01.10.2022


Ecotoxicological responses of Daphnia magna and Eisenia andrei in landfill leachate

Abstract

Leachate toxicity using bioindicators such as microcrustaceans and earthworms has not been fully elucidated. These bioindicators are traditionally determined through physicochemical and microbiological analyses. The ecotoxicological assessment of leachate using indicator organisms from different environments is a technique to ensure the treatment and safe disposal of this effluent with minimum impact on human health and the environment. The current study aimed to evaluate the ecotoxicological responses of Daphnia magna and Eisenia andrei in landfill leachate, identifying which organism was more sensitive to this effluent. The leachate used in ecotoxicological tests was collected at the Campina Grande Sanitary Landfill (ASCG), Paraíba, Brazil. The leachate sample contained a high content of organic matter in the form of chemical oxygen demand (19496.86 mg.L−1) and ammoniacal nitrogen (2198.00 mg.NL−1), in addition to metals with carcinogenic potential, such as Cr (0.64 mg.L−1) and Fe (1.16 mg.L−1). The exposure of Daphnia magna to the leachate showed that the effluent is harmful to aquatic organisms, obtaining an EC 50, 48 h = 1.22%, FT of 128 and a TU of 81.96%. Among the contaminant concentrations tested in Eisenia andrei, 57% (59.28 mL.kg−1) caused the highest lethality, causing the death of 21 earthworms within 72 hours of exposure. The avoidance test showed that exposure to leachate concentrations between 10.38 and 39.86 mL.kg−1 led to the leakage of earthworms, and habitat loss was observed at a concentration of 55.80 mL.kg−1, in which leak response (LR) ≥80% was obtained. This study demonstrates that the mentioned organisms are suitable for ecotoxicological tests in landfill leachate. Moreover, the microcrustacean Daphnia magna showed the most significant sensitivity, presenting a rapid ecotoxicological response to the leachate.


Datum: 01.10.2022


Starvation and cadmium affect energy reserves and oxidative stress in individuals of Spodoptera exigua

Abstract

Different factors, such as starvation and metal exposure, may affect development and cause oxidative stress in insects. Some host plants may contain a high concentration of cadmium due to their hyperaccumulating property. The negative effects of metals and hunger may be manifested by low availability of energetic substrates. This study aimed to assess whether the insect population with a history of long metal exposure may better manage metal stress or/and starvation at different developmental stages, with the use of energetic substrates. Two strains of Spodoptera exigua model organism were tested: control strain and cadmium strain (treated continuously for over 200 generations with subtoxic amounts of cadmium). The effects of different factors, individually and in combination, on the tested strains were assessed, first by determining the body weight of larvae and pupae and then by estimating the concentration of biomolecules (proteins, carbohydrates, lipids, or glycogen) in the 4th and 5th larval stages and in pupae, and the total antioxidant capacity and lipid peroxidation level in the 4th larval stage. Compared to control strain, cadmium strain individuals exhibited changes in the concentration of soluble carbohydrates and protein. This was partly related to earlier 1-day starvation. In particular, changes in carbohydrate concentration seemed to be a sensitive biomarker of metal stress, independent of the age of individuals and period of starvation. However, the increase in the total antioxidant capacity and the concentration of lipid peroxidation products in the 4th larval stage under the effect of cadmium was dependent on strain origin.


Datum: 29.09.2022


Environmental impacts due to the use of sunscreen products: a mini-review

Abstract

Sunscreen use has increased in recent years, as sunscreen products minimize the damaging effects of solar radiation. Active ingredients called ultraviolet (UV) filters or UV agents, either organic or inorganic, responsible for defending skin tissue against harmful UV rays, are incorporated in sunscreen formulations. UV agents have a serious impact on many members of bio communities, and they are transferred to the environment either directly or indirectly. Many organic UV filters are found to be accumulated in marine environments because of high values of the octanol/water partition coefficient. However, due to the fact that UV agents are not stable in water, unwanted by-products may be formed. Experimental studies or field observations have shown that organic UV filters tend to bioaccumulate in various aquatic animals, such as corals, algae, arthropods, mollusks, echinoderms, marine vertebrates. This review was conducted in order to understand the effects of UV agents on both the environment and marine biota. In vivo and in vitro studies of UV filters show a wide range of adverse effects on the environment and exposed organisms. Coral bleaching receives considerable attention, but the scientific data identify potential toxicities of endocrine, neurologic, neoplastic and developmental pathways. However, more controlled environmental studies and long-term human use data are limited. Several jurisdictions have prohibited specific UV filters, but this does not adequately address the dichotomy of the benefits of photoprotection vs lack of eco-friendly, safe, and approved alternatives.


Datum: 29.09.2022


Cold storage effects on lethal and sublethal responses of Amphibalanus amphitrite Nauplii

Abstract

Bioassays are extensively used in ecotoxicology and there is a constant need for even more sensitive, reliable and easy to rear and obtain model organisms. Larvae of the crustacean Amphibalanus amphitrite are a good ecotoxicological model, for their high sensitivity to a wide range of toxicants and emerging contaminants. A standardized protocol for this toxicity bioassay has been recently proposed. Nevertheless, a limit of this model organism is the lack of resting stages and the need to use larvae immediately after their release from adults, thus increasing laboratory efforts related to the maintenance of adults. The aim of this work is to verify if short-term cold storage of A. amphitrite larvae prior to use in ecotoxicological tests may affect the ecotoxicological responses of these organisms. Three end-points (mortality, immobilization and swimming speed alteration) were measured on nauplii after storing them at 4 ± 1 °C for different times (24, 72 and 120 h) before bioassay set-up. Bioassays were set up using: (i) clean filtered natural sea water (0.22 µm FNSW), (ii) a reference toxicant (Cadmium Nitrate) and (iii) an environmental matrix (sediment elutriate). Results show that mortality, differently from the other two endpoints, was not affected by cold-storage. Even after 5 days of larvae storage at 4 ± 1 °C before bioassay set up, mortality data were comparable to those obtained for non-cold-stored organisms. Moreover, larval sensitivity to the reference toxicant and sediment elutriate did not change. Regarding the other two end points, low cadmium concentrations significantly changed immobility and swimming activity in cold-stored nauplii compared to larvae used immediately after larval release. In conclusion, short-term cold storage of A. amphitrite nauplii before bioassay set up is an appropriate procedure in ecotoxicological testing if mortality is the endpoint to be considered for final evaluation.


Datum: 01.09.2022


Toxicity of perfluoroalkyl substances (PFAS) toward embryonic stages of mahi-mahi (Coryphaena hippurus)

Abstract

Perfluoroalkyl substances (PFAS) are highly persistent organic pollutants that have been detected in a wide array of environmental matrices and, in turn, diverse biota including humans and wildlife wherein they have been associated with a multitude of toxic, and otherwise adverse effects, including ecosystem impacts. In the present study, we developed a toxicity assay for embryonic stages of mahi-mahi (Coryphaena hippurus), as an environmentally relevant pelagic fish species, and applied this assay to the evaluation of the toxicity of “legacy” and “next-generation” PFAS including, respectively, perfluorooctanoic acid (PFOA) and several perfluoroethercarboxylic acids (PFECA). Acute embryotoxicity, in the form of lethality, was measured for all five PFAS toward mahi-mahi embryos with median lethal concentrations (LC50) in the micromolar range. Consistent with studies in other similar model systems, and specifically the zebrafish, embryotoxicity in mahi-mahi generally (1) correlated with fluoroalkyl/fluoroether chain length and hydrophobicity, i.e., log P, of PFAS, and thus, aligned with a role of uptake in the relative toxicity; and (2) increased with continuous exposure, suggesting a possible role of development stage specifically including a contribution of hatching (and loss of protective chorion) and/or differentiation of target systems (e.g., liver). Compared to prior studies in the zebrafish embryo model, mahi-mahi was significantly more sensitive to PFAS which may be related to differences in either exposure conditions (e.g., salinity) and uptake, or possibly differential susceptibility of relevant targets, for the two species. Moreover, when considered in the context of the previously reported concentration of PFAS within upper sea surface layers, and co-localization of buoyant eggs (i.e., embryos) and other early development stages (i.e., larvae, juveniles) of pelagic fish species to the sea surface, the observed toxicity potentially aligns with environmentally relevant concentrations in these marine systems. Thus, impacts on ecosystems including, in particular, population recruitment are a possibility. The present study is the first to demonstrate embryotoxicity of PFAS in a pelagic marine fish species, and suggests that mahi-mahi represents a potentially informative, and moreover, environmentally relevant, ecotoxicological model for PFAS in marine systems.


Datum: 01.09.2022


Heavy metals and parasitological infection associated with oxidative stress and histopathological alteration in the Clarias gariepinus

Abstract

The goal of this study was to assess the harmful effects of heavy metal accumulation on Clarias gariepinus (catfish) in two different polluted areas in the Al Sharkia governorate and assess the impact on oxidative stress and histological changes. The results revealed a highly significant difference in heavy metal levels in the water and inside fish tissues (liver and gonads) between the two sites. The total prevalence of parasitic infection was at the highest percentage in area B, in addition to severe histopathological damage to the liver and the gonads. Findings show that the total prevalence of parasitic infection is associated with uptake of metals, depleted antioxidant activity, and incidence of lipid peroxidation in tissue.


Datum: 01.09.2022


Occurrence and distribution of antibiotics in surface water

Abstract

The concentrations, distribution, and ecological risks of 24 typical antibiotics in Hong Kong rivers and seawater were investigated using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UHPLC-EI-MS/MS). The results showed that the select antibiotics were widely distributed in the study area. Among the target antibiotics, the detection rate of tetracyclines (TCs) was 100%, which indicated the widespread use of TCs in Hong Kong. The detection rates of sulfonamides (SAs) (57.1–100%), fluoroquinolones (FQs) (78.6–100%), roxithromycin (RTM) (50%) and novobiocin (NOV) (50%) were all above 50%. Compared with river water (7.9–114.26 ng/L, medium: 27.7 ng/L), concentrations of the most antibiotics in seawater (9.5–32.0 ng/L, medium: 13.3 ng/L) were lower; seawater concentrations were similar to those reported from other coastal cities, such as Guangzhou and Zhuhai in China, which implied that the source of marine antibiotic pollution may be the nearby rivers, and the vastness of the ocean causes environmental dilution of antibiotics. According to the ratio of the measured environmental concentration (MEC) to the predicted no-effect concentration (PNEC), ofloxacin (OFX) (average risk quotient: 1.94E–01) and ciprofloxacin (CFX) (average risk quotient: 3.53E–01) posed medium to high ecological risk in most places, whereas other antibiotics posed lower risk. In Yuen Long, where there were many livestock farms nearby, the detected concentration of antibiotics was higher, indicating that livestock wastewater may be the major reason for the increase in antibiotic levels in this area. In general, the detected concentration of antibiotics in Hong Kong was lower than that in the United States, Japan, the United Kingdom, and coastal areas of China, but the long-term existence of low concentrations of antibiotics also poses great risks. According to the risk assessment, Hong Kong should pay more attention to the use of FQs (e.g., OFX and CFX) in the future.


Datum: 01.09.2022


Toxicity of lanthanides on various fish cell lines

Abstract

The growing use of Lanthanides in new technologies has increased their anthropogenic releases into the aquatic environment over the last decades. However, knowledge on their ecotoxicological impacts is still incomplete, especially with regard to biological effects of Lanthanides mixtures and the possible regular variation in toxicity along the Lanthanides series. The present study evaluated the individual toxicity of all Lanthanides and the toxicity of mixtures of three of them, namely Neodymium (Nd3+), Gadolinium (Gd3+), and Ytterbium (Yb3+) on Danio rerio fibroblast-like cells (ZF4). Individual and mixtures toxicity of Neodymium (Nd3+) and Ytterbium (Yb3+) were also assessed on Danio rerio hepatic cells (ZFL) and Oncorhynchus mykiss epithelial cells (RTgill-W1). The measured Lanthanide concentrations were close to the nominal ones in the culture media of ZF4, ZFL, and RTgill-W1 cells (85–99%). A toxic impact was observed on the three fish cell lines exposed to all Lanthanides tested individually. RTgill-W1 appeared as the less sensitive cells, compared to the two others. Four Lanthanides, Erbium (Er3+), Thulium (Tm3+), Ytterbium (Yb3+) and Lutetium (Lu3+) showed a higher toxicity than the others on ZF4 cells but no correlation could be established between the toxicity of Lanthanides and the order of the elements within the Lanthanides series. Exposures to binary mixtures highlighted the presence of synergistic effects on cell viability for all cell lines.


Datum: 01.09.2022


Effects of the antifouling agent tributyltin on the sinking behavior, photosynthetic rate and biochemical composition of the marine planktonic diatom Thalassiosira pseudonana

Abstract

This study investigated the changes in the sinking rates and physiochemical characteristics of the planktonic marine diatom, Thalassiosira pseudonana, caused by 72 h exposure to antifouling agent tributyltin (TBT) at 1.0 µg L−1 (72-h 10% effective concentration for growth rate, EC10), and 1.7 µg L−1 (EC50). After 72 h of exposure, the sinking rates of T. pseudonana cells were changed from 0.13–0.08 m day−1 in the control, 0.08–0.05 m day−1 in the EC10 treatment, and 0.04–0.006 m day−1 in the EC50 treatment. The results revealed that the sinking rate of T. pseudonana decreased significantly compared with the control at 48 h in the EC10 treatment group and at 24, 48, and 72 h in the EC50 treatment group. The photosynthetic performance index on an absorption basis and the maximum quantum yields of photosystem II also decreased significantly (P < 0.05) in the TBT treatments compared with the control. There was a significant (P < 0.05) positive correlation between sinking rates and cellular protein contents (ng cell−1). Changes in the biochemical and physiochemical composition of the cells suggest that interference with photosynthetic processes by TBT may have reduced their specific gravity and thereby caused a decrease in the sinking rates of T. pseudonana. The results of this investigation suggest the importance of considering the effects of pollutants on the sinking behaviors of diatoms when evaluating the adverse effects of pollutants on marine primary production.


Datum: 01.09.2022


 


Category: Current Chemistry Research

Last update: 28.03.2018.






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