Toxicity of urban stormwater on Chlorella pyrenoidosa: Implications for reuse safety

Urban stormwater is an alternative water source used to mitigate water resource shortages, and ensuring the safety of stormwater reuse is essential. An in-depth understanding of both individual pollutant concentrations/loads in stormwater and holistic stormwater quality can be used to comprehensively evaluate how safely stormwater can be reused. The toxicity test takes all pollutants present in water samples into account, and the results reflect the integrated effect of these pollutants. In this study, the influence of urban stormwater sourced from different land uses on microalgae (Chlorella pyrenoidosa) and the possible toxicity mechanisms were investigated. The results showed that urban stormwater, particularly residential road stormwater, significantly inhibited microalgal growth. The chlorophyll contents of microalgae exposed to residential road stormwater were relatively lower, while the corresponding values were relatively higher for microalgae exposed to grassland road stormwater. Additionally, the antioxidant-related metabolism of microalgae could be dysregulated due to exposure to urban stormwater. A possible toxicity mechanism is that urban stormwater influences metabolic pathways related to chlorophyll synthesis and further hinders photosynthesis and hence microalgal growth. To resist oxidative stress and maintain regular microalgal cell activities, the ribosome metabolism pathway was upregulated. The research results contribute to elucidating the toxicity effects of urban stormwater and hence provide useful insight for ensuring the safety of stormwater reuse. It is also worth noting that the study outcomes can only represent the influence of land use on stormwater toxicity, while the impacts of other factors (particularly rainfall-runoff characteristics) have not been considered. Therefore, the consideration of all influential factors of stormwater is strongly recommended to generate more robust results in the future and provide more effective guidance for real practices related to stormwater reuse safety.

Evaluation of short-term copper toxicity in a co-culture of Synechococcus sp., Chaetoceros gracilis and Pleurochrisys cf. roscoffensis exposed to changes in temperature and salinity levels

Metals such as copper (Cu) enter marine environments from natural and anthropogenic sources, causing changes in the biodiversity of marine microalgae and cyanobacteria. Cu plays a dual role as either a micronutrient or toxicant depending on the environmental concentration. Many studies have summarized the potential of Cu to become more toxic to microalgae under environmental stress (for instance climate change). Most of the data available on Cu toxicity concerning microalgae and cyanobacteria have been produced using single-species laboratory tests, and there is still a significant gap in the information concerning the behavior of a group of algae exposed to environmental stressors. Thus, the objective of this study was to evaluate the toxicity of Cu at two concentrations (C1 = 2 μg L-1 and C2 = 5 μg L-1) in multispecies bioassays using three phytoplankton species (one cyanobacteria, Synechococcus sp., and two microalgae, Chaetoceros gracilis and Pleurochrisys cf. roscoffensis). Combinations of two temperatures (20 and 23 °C) and two salinities (33 and 36 PSU), were applied in a 96 h study using flow cytometry analysis (FCM). Algal growth and reactive oxygen species (ROS) production by 2'7'-dichlorofluorescein (DCFH) were monitored by FCM. The results indicated that Synechococcus sp. was more sensitive than C. gracilis and P. roscoffensis to Cu stress at a temperature 23 °C and salinity of 36 PSU under both concentrations of Cu. Chlorophyll a fluorescence showed a significant decrease (p < 0.05) in Synechococcus sp. under 5 μg L-1 of Cu in the combined treatment of 20 °C and 33 PSU; however, there was a significant increase in P. roscoffensis in all combinations at C2 = 5 μg L-1 compared to the control with no Cu, indicating a potential hormetic response to Cu for P. roscoffensis. ROS levels were triggered in a combination of 23 °C and 33 PSU and 5 μg L-1 of Cu, which was higher than all the other combinations studied. Our study resulted in data concerning the potential impacts caused by possible future climate change scenarios in aquatic habitats chronically exposed to metals.

The use of integrative tools and multiple models for aquatic environmental quality assessment: a case study of the Mirim Lagoon, Southern Brazil

This study performed toxicity assays with microalgae, microcrustaceans, and fish as well as evaluated biochemical and behavioral biomarkers in fish and microcrustaceans to assess the quality of the surface water of Mirim Lagoon, which belongs to one of the largest hydrographic basins in the world, located in southern Brazil. Three distinct sampling periods were chosen (January, March, and June 2022) based on the rice plantation dynamics which is the main activity surrounding the lagoon. In January, the plantation is irrigated; in March, the water is drained into the Mirim Lagoon, and July is the off-season. Concerning toxicity tests, there was significant inhibition in microalgae growth when exposed to water collected in March, but no mortality was observed for Ceriodaphia dubia, Daphnia magna, and Danio rerio. Regarding biomarkers, behavioral variables contributed more to the higher values of the Integrated Biomarker Response (IBR) index for both D. magna and D. rerio, in March. The Redundancy Analysis (RDA) indicated a correlation between the biomarkers for both organisms and abiotic parameters, mainly nutrients (total phosphorus and total nitrogen), thermotolerant coliforms, total solids, and turbidity. Spatially, there was no difference during monitoring, but the most significant ecotoxicological effects were observed in March. Multivariate analysis and the IBR index proved to be useful tools for monitoring of water bodies such as Mirim Lagoon.

Biodegradation and Detoxification of Low-Density Polyethylene (LDPE) by Stenotrophomonas sp. and Alcaligenaceae bacterium

Every year, human activities introduce large amounts of synthetic plastics into the environment. Decomposition of the plastic derivatives is very difficult and time consuming, so it is essential to eliminate these pollutants using different methods. Bioremediation, is suitable option, because of the low cost and environmentally safe. In this research, degradation of low-density polyethylene (LDPE) was investigated by two strains, isolated from Hamadan province (Iran) landfill soil. After identification by 16sr DNA primers, their abilities of polyethylene biodegradation were examined by Fourier transform infrared (FTIR), SEM and Gas Chromatography-Mass Spectrometry (GC-MS). Using media contain polyethylene) after and before addition of bacteria), toxicity test was conducted by measuring the germination index, root and hypocotyl length of Lactuca sativa seed. After three months, 10.15% ± 1.04 weight loss of LDPE achieved through strain Stenotrophomonas sp. degradation. Both strains had high biofilm formation capacity, confirmed by Electron microscope images and FTIR analysis. GC-MS confirmed the presence of the end-product of LDPE degradation (Pentacosane, Hexacosane, and Octadecane). Both, Stenotrophomonas sp. and Alcaligenaceae bacterium had significant detoxification ability. In media contain LDPE (without bacteria), decrease in the germination of lettuce seeds was observed.

Behavioural, developmental and biochemical effects in zebrafish caused by ibuprofen, irgarol and terbuthylazine

The increasing use of chemicals and their release into aquatic ecosystems are harming aquatic biota. Despite extensive ecotoxicological research, many environmental pollutants' ecological effects are still unknown. This study examined the spatial avoidance, behavioural and biochemical impacts of ibuprofen, irgarol, and terbuthylazine on the early life stages of zebrafish (Danio rerio) under a range of ecologically relevant concentrations (0-500 μg/L). Embryos were exposed following the OECD guideline "fish embryo toxicity test" complemented with biochemical assessment of AChE activity and behavioural analyses (swimming activity) using the video tracking system Zebrabox. Moreover, spatial avoidance was assessed by exposing 120 hpf-old larvae of D. rerio to a gradient of each chemical, by using the heterogeneous multi-habitat assay system (HeMHAS). The results obtained revealed that the 3 compounds delayed hatching at concentrations of 50 and 500 μg/L for both ibuprofen and irgarol and 500 μg/L for terbuthylazine. Moreover, all chemicals elicited a dose-dependent depression of movement (swimming distance) with LOEC values of 5, 500 and 50 μg/L for ibuprofen, irgarol and terbuthylazine, respectively. Zebrafish larvae avoided the three chemicals studied, with 4 h-AC50 values for ibuprofen, irgarol, and terbuthylazine of 64.32, 79.86, and 131.04 μg/L, respectively. The results of the HeMHAS assay suggest that larvae may early on avoid (just after 4 h of exposure) concentrations of the three chemicals that may later induce, apical and biochemical effects. Findings from this study make clear some advantages of using HeMHAS in ecotoxicology as it is: ecologically relevant (by simulating a chemically heterogeneous environmental scenario), sensitive (the perception of chemicals and the avoidance can occur at concentrations lower than those producing lethal or sublethal effects) and more humane and refined approach (organisms are not mandatorily exposed to concentrations that can produce individual toxicity).

In Vivo Toxicity of Industrial Biocide Containing 2,2-Dibromo-3-nitrilopropionamide in Adult and Zebrafish Larvae

2,2-Dibromo-3-nitrilopropionamide (DBNPA) is a widely used biocide with potential environmental implications due to its toxicity. This study aimed to investigate the in vivo toxicity of DBNPA in zebrafish (Danio rerio), a model organism in environmental toxicology. Both adult and larval zebrafish were exposed to varying concentrations of DBNPA, and significant morphological changes and mortality rates were observed. The study found that even relatively low concentrations of DBNPA can have detrimental effects on zebrafish embryonic development, and high concentrations resulted in rapid mortality in adult zebrafish and larvae. The LC50 values calculated from this study were 9.3 ppm for adults and 9.1 ppm for larvae, indicating the high toxicity of DBNPA to these organisms. These findings underscore the potential environmental impact of DBNPA and highlight the need for further research into its effects on aquatic ecosystems.

Release characteristics and toxicity assessment of micro/nanoplastics from food-grade nonwoven bags

Micro/nanoplastic (M/NP) contamination in food has become a global concern. Food-grade polypropylene (PP) nonwoven bags, which are widely used to filter food residues, are considered environmentally friendly and nontoxic. However, the emergence of M/NPs has forced us to re-examine the use of nonwoven bags in cooking as plastic contact with hot water leads to M/NP release. To evaluate the release characteristics of M/NPs, three food-grade PP nonwoven bags of different sizes were boiled in 500 mL water for 1 h. Micro-Fourier transform infrared spectroscopy and Raman spectrometer confirmed that the leachates were released from the nonwoven bags. After boiling once, a food-grade nonwoven bag can release 0.12-0.33 million MPs (>1 μm) and 17.6-30.6 billion NPs (<1 μm), equivalent to a mass of 2.25 - 6.47 mg. Number of M/NPs released is independent of nonwoven bag size; however, it decreases with increasing cooking times. M/NPs are primarily produced from easily breakable PP fibers, and they are not released into the water at once. Adult zebrafish (Danio rerio) were cultured in filtered distilled water without released M/NPs and in water containing 14.4 ± 0.8 mg L^-1 released M/NPs for 2 and 14 days, respectively. To evaluate the toxicity of the released M/NPs on the gills and liver of zebrafish, several oxidative stress biomarkers (i.e., reactive oxygen species, glutathione, superoxide dismutase, catalase, and malonaldehyde) were measured. The ingestion of the released M/NPs by zebrafish induces oxidative stress in the gills and liver, depending on the exposure time. Food-grade plastics, such as nonwoven bags, should be used with caution in daily cooking because they release large amounts of M/NPs when heated, which can threaten human health.

Antidepressant evaluation of Andrographis paniculata Nees extract and andrographolide in chronic unpredictable stress zebrafish model

Andrographis paniculata (A. paniculata) showed an anti-depressive effect in rodent models. Zebrafish has recently emerged as a worthy complementary translational model for antidepressant drug discovery study. This study investigates the anti-depressive effect of A. paniculata extract and andrographolide in the chronic unpredictable stress (CUS)- zebrafish model. Four groups of zebrafish (n = 10/group), i.e. control, CUS (stressed, untreated), CUS + A. paniculata (100 mg/L) and CUS + fluoxetine (0.01 mg/L) were assessed in open-field and social interaction tests, 24 h after treatment. After extract screening, behavioural and cortisol analysis of andrographolide (5, 25 and 50 mg/kg, i.p.) and fluoxetine (10 mg/kg, i.p.) were evaluated. Before the behavioural study, acute toxicity and characterization of A. paniculata extract using UHPLC-ESI-MS/MS were performed. A significant reduction in freezing duration was found in A. paniculata- (t-test, p = 0.0234) and fluoxetine-treated groups (t-test, p < 0.0001) compared to the CUS group. A significant increase in total distance travelled, and contact duration was observed only in the fluoxetine-treated group (t-test, p = 0.0007) and (t-test, p = 0.0207), respectively. A significant increase in highly mobile duration was observed in both treatment groups. Andrographolide (50 mg/kg, i.p.) acute treatment showed a significant reduction in freezing duration (p = 0.0042), duration in a dark area (p = 0.0338) and cortisol level (p = 0.0156) and increased total distance travelled (p = 0.0144). Twenty-six compounds were tentatively characterized by LC-MS/MS method, and andrographolide content is 0.042 μg/g. According to cortisol analysis, A. paniculata's LC₅₀ is 627.99 mg/L, while andrographolide's EC₅₀ was determined as 26.915 mg/kg. Further assessment of the cellular and molecular underpinnings of the anti-depressive effect of andrographolide is strongly recommended to evaluate the potential as an antidepressant.

Do new cement-based mortars pose a significant threat to the aquatic environment?

Nowadays, the use of multi-functional mortars has increased significantly, with interesting applications in the sustainable construction. In the environment, the cement-based materials are subjected to leaching, so the assessment of potential adverse effects upon aquatic ecosystem is necessary. This study focuses on the evaluation of the ecotoxicological threat and of a new type of cement-based mortar (CPM-D) and its raw materials leachates. A screening risk assessment were performed by Hazard Quotient methods. The ecotoxicological effects were investigated by a test battery with bacteria, crustacean, and algae. Two different procedures, Toxicity test Battery Index (TBI) and Toxicity Classification System (TCS), to obtain a single value for toxicity rank were used. Raw materials showed the highest metal mobility and in particular, for Cu, Cd and V potential hazard was evidenced. Leachate toxicity assessment evidenced the highest effects linked to cement and glass while the mortar showed the lowest ecotoxicological risk. TBI procedure allows a finer classification of effect linked to materials with respect to TCS which is based on worst case approach. A safe by design approach taking into account the potential and the effective hazard of the raw materials and of their combinations could allow to achieve sustainable formulations for building materials.

The current state of ayahuasca research in animal models: A systematic review

RATIONALE

The psychedelic brew ayahuasca is increasingly being investigated for its therapeutic potential. Animal models are essential to investigate the pharmacological effects of ayahuasca since they can control important factors influencing it, such as the set and setting.

OBJECTIVE

Review and summarise data available on ayahuasca research using animal models.

METHODS

We systematically searched five databases (PubMed, Web of Science, EMBASE, LILACS and PsycInfo) for peer-reviewed studies in English, Portuguese or Spanish published up to July 2022. The search strategy included ayahuasca- and animal model-related terms adapted from the SYRCLE search syntax.

RESULTS

We identified 32 studies investigating ayahuasca effects on toxicological, behavioural and (neuro)biological parameters in rodents, primates and zebrafish. Toxicological results show that ayahuasca is safe at ceremonial-based doses but toxic at high doses. Behavioural results indicate an antidepressant effect and a potential to reduce the reward effects of ethanol and amphetamines, while the anxiety-related outcomes are yet inconclusive; also, ayahuasca can influence locomotor activity, highlighting the importance of controlling the analysis for locomotion when using tasks depending on it. Neurobiological results show that ayahuasca affects brain structures involved in memory, emotion and learning and that other neuropathways, besides the serotonergic action, are important in modulating its effects.

CONCLUSIONS

Studies using animal models indicate that ayahuasca is toxicologically safe in ceremonial-comparable doses and indicates a therapeutic potential for depression and substance use disorder while not supporting an anxiolytic effect. Essential gaps in the ayahuasca field can still be sufficed using animal models.

Study on the toxic effects of sodium pentachlorophenol (PCP-Na) on razor clam (Sinonovacula constricta)

Currently, research on toxic effects of PCP Na is greatly insufficient. The aim of this study is to explore the toxic effects of PCP-Na for better conducting future work on PCP-Na toxicology. For this purpose, S. constricta adults were exposed to PCP-Na for toxicity testing. The results showed that PCP-Na could easily bioaccumulate in S. constricta and significantly affected both phrase I and II metabolism enzymes. Meanwhile, PCP-Na strongly activated antioxidant system and caused PC, LPO and DNA damage. In addition, neurotoxicity and immunotoxicity of PCP-Na was demonstrated in this study. Interestingly, we observed that PCP-Na significantly affected the expression of genes of electron transport chain and induced key enzymes of glycolysis, indicating that PCP-Na may act as an uncoupler of oxidative phosphorylation, interfering with energy supply and causing energy compensation. This study is the first to fully analyze and provide a new perspective on the toxicity of PCP-Na.

Comparison of the sensitivity between indigenous and exotic aquatic species for fluoranthene and derivation of water quality criteria (WQC)

Fluoranthene (FLU) has shown relatively high toxicity to aquatic life as a priority polycyclic aromatic hydrocarbon (PAH). Considering the toxic effects of FLU on aquatic organisms and its high detection frequency in the aquatic environment, it is necessary and critical to derive FLU water quality criteria (WQC) for the protection of aquatic organisms and ecological risk assessment. However, due to the lack of toxicity data at different classification levels, there has been no research about the WQC of FLU. In this study, nine acute and three chronic toxicity tests were carried out on 9 Chinese indigenous aquatic species from different classification levels to obtain toxicity data. According to the US EPA guidelines, the criterion maximum concentration of 0.570 mg/L and the criterion continuous concentration of 0.174 mg/L were developed. There is no significant difference when comparing the species sensitivity distributions between indigenous and exotic species. Therefore, it is possible to use toxicity data from organisms in different areas for ecological risk assessment of FLU. CAPSULE: We compared the sensitivity between indigenous and exotic aquatic species for fluoranthene and derived its water quality criteria.

From molecular endpoints to modeling longer-term effects in fish embryos exposed to the elutriate from Doce River

Sediments represent a major sink and also a main source of contaminants to aquatic environments. An environmental disaster from a mining dam breakage in 2015 in South-East Brazil re-suspended complex mixtures of chemicals deposited in the sediment, spreading contaminants along the Doce River Basin (DRB) major river course. While high levels of contaminants in sediment were well described, toxicological effects in aquatic organisms were poorly investigated. Thus, the effects of these potentially toxic chemicals were assessed in the present study through different endpoints (biochemical to populational levels) in fish embryos of the South-American silver catfish exposed to elutriates from different sites of the DRB. Despite no significant mortality observed, our results showed that exposure to the elutriates, especially those from the closest site to the dam collapse, caused higher deformities rates and DNA damage in the fish embryos than in the control group. Multivariate analysis showed that these sublethal effects may be related to the high levels of metals introduced by mining activities, compromising long-term survival and reproduction success. In addition, it was possible to observe the influence of other sources of pollutants along the river. According to our data, the mathematical model simulated a significant impact on the population density at longer-term exposure, for the sites that showed the most prominent toxicity responses. The fish embryo toxicity test proved to be an effective assay to assess the ecotoxicological effects of the pollutants from a major river contaminated by a mining dam collapse and showed that the survival rate per se was not a suitable endpoint to assess the toxicity of the pollutants. As a consequence, we contributed to shed a light on a potential underestimated impact of pollutants in sediments of the DRB on the native organisms at distinct biological levels of organizations.

Commercial pesticides for urban applications induced population growth and sub-cellular alterations in Raphidocelis subcapitata (Chlorophyceae) at concerning environmental concentrations

Information regarding the safety and environmental risks of pesticides intended for urban use remains limited. This study aimed to assess the effects of four common pesticides on the microalga Raphidocelis subcapitata: DIAZINON® 25% C. E., Roundup®, URBACIN® 20C. E., and VAPODEL® 20% C. E., which are commercial formulations of diazinon, glyphosate, dichlorvos, and cypermethrin, respectively. According to 96-h inhibition of population growth bioassays, the four pesticide toxicities exemplified the following order: DIAZINON® (diazinon) > Roundup® (glyphosate) > VAPODEL® (dichlorvos) > URBACIN® (cypermethrin). Increasing pesticide concentrations elicited alterations in the specific growth rates (µmax). The macromolecule contents and photosynthetic pigments increased in groups exposed to the highest concentrations of DIAZINON® 25%, Roundup®, and URBACIN® 20 compared to the control group, despite these treatments inducing lower population growth rates. VAPODEL® 20% induced higher growth rates and lower macromolecule content compared to the control. Since active ingredients were not quantified, certain comparisons may prove limiting, but it is important to assess the effects of the whole mixtures in the form that they enter the environment, especially for urban-intended applications or generic formulations with higher additive contents. Finally, this study demonstrated that commercial pesticide formulations designed for urban applications might pose a threat to freshwater microalgae due to their underestimated toxic potential, but further studies are required.

Acute and multigenerational effects of petroleum- and cellulose-based microfibers on growth and photosynthetic capacity of Lemna minor

Comparative toxicological assessment studies on the effects of petroleum- and cellulose-based microfibers on aquatic plants are limited. Therefore, we evaluated the acute and 10-generational toxicological effects of two types of petroleum- and cellulose-based microfibers on the duckweed Lemna minor. Plant growth and photosynthesis parameters were monitored as bioindicators. The multigenerational test revealed the following ranking of the microfibers according to the severity of their effects on L. minor: polypropylene > lyocell > viscose > polyethylene terephthalate. The acute tests revealed a significant increase in the energy required to initiate photosynthesis, although the growth of L. minor was not adversely affected by any microfiber. Both petroleum- and cellulose-based microfibers induced adverse effects on the growth and photosynthesis of L. minor in multigenerational tests. The results of the generational tests contribute to the understanding of the long-term adverse effects of microfibers on aquatic plants.

Characterization of Immobilized Magnetic Fe3O4 Nanoparticles on Raoultella Ornithinolytica sp. and Its Application for Azo Dye Removal

A high-performance immobilized bacterial strain coated with magnetic iron oxide nanoparticles was used for Basic Blue 41 azo dye (BB 41 dye) decolorization. To create the coated bacterial strain, Raoultella Ornithinolytica sp. was isolated and identified under the accession number KT213695, then coated with manufactured magnetic iron oxide nanoparticles. SEM and SEM-EDX were used to characterize the coated bacteria and validate its morphological structure formation. The coated Raoultella Ornithinolytica sp. A1 (coated A1) generated a 95.20% decolorization for BB 41 dye at 1600 ppm starting concentration with an optimal dose of coated A1 5 mL/L, pH 8, under static conditions for 24 h at 37 °C. Continuous batch cycles were used, with BB 41 dye (1600 ppm) added every 24 h four times, to achieve a high decolorization efficiency of 80.14%. Furthermore, the metabolites of BB 41 dye biodegradation were investigated by gas chromatographic-mass spectrum analysis (GC-MS) and showed a less toxic effect on the bioindicator Artemia salina. Additionally, 5 mL/L of coated A1 demonstrated the highest decolorization rate (47.2%) when applied to a real wastewater sample after 96 h with a consequent reduction in COD from 592 to 494 ppm.

Current technologies and future perspectives for the treatment of complex petroleum refinery wastewater: A review

Petroleum refinery wastewater (PRW) is a complex mixture of hydrocarbons, sulphides, ammonia, oils, suspended and dissolved solids, and heavy metals. As these pollutants are toxic and recalcitrant, it is essential to address the above issue with efficient, economical, and eco-friendly technologies. In this review, initially, an overview of the characteristics of wastewater discharged from different petroleum refinery units is discussed. Further, various pre-treatment and post-treatment strategies for complex PRW are introduced. A segregated approach has been proposed to treat the crude desalting, sour, spent caustic, and oily wastewater of petroleum refineries. The combined systems (e.g., ozonation + moving bed biofilm reactor and photocatalysis + packed bed biofilm reactor) for the treatment of low biodegradability index wastewater (BOD₅/COD < 0.2) were discussed to construct a perspective map and implement the proposed system efficiently. The economic, toxicity, and biodegradability aspects are also introduced, along with research gaps and future scope.

Microbial bioremediation of produced water under different redox conditions in marine sediments

The discharge of produced water from offshore oil platforms is an emerging concern due to its potential adverse effects on marine ecosystems. In this study, we investigated the feasibility and capability of using marine sediments for the bioremediation of produced water. We utilized a combination of porewater and solid phase analysis in a series of sediment batch incubations amended with produced water and synthetic produced water to determine the biodegradation of hydrocarbons under different redox conditions. Significant removal of benzene, toluene, ethylbenzene and xylene (BTEX) compounds was observed under different redox conditions, with biodegradation efficiencies of 93-97% in oxic incubations and 45-93% in anoxic incubations with nitrate, iron oxide or sulfate as the electron acceptor. Higher biodegradation rates of BTEX were obtained by incubations dominated by nitrate reduction (104-149 nmolC/cm³/d) and oxygen respiration (52-57 nmolC/cm³/d), followed by sulfate reduction (14-76 nmolC/cm³/d) and iron reduction (29-39 nmolC/cm³/d). Chemical fingerprint analysis showed that hydrocarbons were biodegraded to smaller alcohols/acids under oxic conditions compared to anoxic conditions with nitrate, indicating that the presence of oxygen facilitated a more complete biodegradation process. Toxicity of treated produced water to the marine copepod Acartia tonsa was reduced by half after sediment incubations with oxygen and nitrate. Our study emphasizes the possibility to use marine sediment as a biofilter for treating produced water at sea without extending the oil and gas platform or implementing a large-scale construction.

Mixture toxicity of six pharmaceuticals towards Aliivibrio fischeri, Daphnia magna, and Lemna minor

As the knowledge on the joint effects of pharmaceuticals towards different non-target organisms is still limited, the aim of our study was to evaluate the toxicity of mixtures of pharmaceuticals, as well as their baseline toxicity towards three selected organisms, namely the bioluminescent bacteria Aliivibrio fischeri, the crustacean Daphnia magna, and the duckweed Lemna minor. Different mixtures composed of three up to five pharmaceuticals having the same or different mechanisms of action in terms of their therapeutic activity (non-steroidal anti-inflammatory drugs, opioid analgesic, antibacterial and anti-epileptic drugs) were investigated. The observed EC₅₀s were compared with those predicted using the concentration addition (CA) and independent action (IA) models. In general, the EC₅₀ values for mixtures predicted with the CA model were lower than those obtained with the IA model, although, in some cases, test predictions of these two models were almost identical. Most of the experimentally determined EC₅₀ values for the specific mixtures were slightly higher than those predicted with the CA model; hence, a less than additive effect was noted. Based on the obtained results, it might be concluded that the CA model assumes the worst-case scenario and gives overall closer predictions; therefore, it should be recommended also for modeling the mixture toxicity of pharmaceuticals with different modes of action.

Microscale Toxicity Identification Evaluation (TIE) for interstitial water of estuarine sediments affected by multiple sources of pollution

Estuaries in the world are affected by different contamination sources related to urbanisation and port/industrial activities. Identifying the substances responsible for the environmental toxicity in estuaries is challenging due to the multitude of stressors, both natural and anthropogenic. The Toxicity Identification and Evaluation (TIE) is a suitable way of determining causes of toxicity of sediments, but it poses difficulties since its application is labour intensive and time consuming. The aim of this study is to evaluate the diagnosis provided by a TIE based on microscale embryotoxicity tests with interstitial water (IW) to identify toxicants in estuarine sediments affected by multiple stressors. TIE showed toxicity due to different combinations of metals, apolar organic compounds, ammonia and sulphides, depending on the contamination source closest to the sampling station. The microscale TIE was able to discern different toxicants on sites subject to different contamination sources. There is good agreement between the results indicated in the TIE and the chemical analyses in whole sediment, although there are some disagreements, either due to the sensitivity of the test used, or due to the particularities of the use of interstitial water to assess the sediment toxicity. The improvement of TIE methods focused on identifying toxicants in multiple-stressed estuarine areas are crucial to discern contamination sources and subsidise management strategies.

Daphnia magna and Ceriodaphnia dubia Have Similar Sensitivity in Standard Acute and Chronic Toxicity Tests

The cladocerans Daphnia magna and Ceriodaphnia dubia have been used for decades to assess the hazards of chemicals and effluents, but toxicity data for these species have traditionally been treated separately. Numerous standard acute and chronic test guidelines have been developed for both species. In the present study, data were compiled and curated for acute survival (48 h) and growth and reproduction tests with D. magna (21 days chronic) and C. dubia (7 days chronic) toxicity assays. Orthogonal regressions were developed to statistically compare the acute and chronic sensitivity of D. magna and C. dubia across a diversity of chemicals and modes of action. Acute orthogonal regressions between D. magna and D. pulex, a widely accepted surrogate species, were used to set a data-driven benchmark for what would constitute a suitable D. magna surrogate. The results indicate that there is insufficient evidence to suggest a difference in acute or chronic sensitivity of D. magna and C. dubia in standard toxicity tests. Further, the variability in the acute D. magna and C. dubia regressions were of the same magnitude as that in D. magna and D. pulex regressions. Slope and y-intercept values were also comparable. The absence of significant differences in toxicity values suggests similar species sensitivity in standard tests across a range of chemical classes and modes of action. Environ Toxicol Chem 2022;41:134-147. © 2021 SETAC.

Can fig and olive ameliorate the toxicity induced by 2-nitropropane in some organs of mice? Role of inflammatory versus anti-inflammatory gene

OBJECTIVE

To investigate the efficacy of Fig fruit powder and olive on hepatic, renal and splenic injury induced by 2-nitropropane (2-NP) in mice, especially if they were used in combination.

METHODS

A total of 40 adult BALB/c male mice weighting 25-30 g/each. Mice were categorized into five groups (8 each). Group 1 as negative control. Group 2 as positive control group intraperitoneally injected with 2-NP (100 mg/kg b. w.) 3 times/weekly for eight weeks. Group 3 injected with 2-NP and were orally supplemented with Fig (300 mg/kg). Group 4 injected with 2-NP and were orally supplemented with olive (100 mg/kg). Group 5 injected with 2-NP and were orally supplemented with mixture of Fig and olive (3:1 respectively).

RESULTS

Histopathological observation of liver in mice treated with 2-NP showed cellular degeneration, pyknosis, and congestion of the portal vein. In kidney there were disorganization of the cortical tissues, cellular necrosis and plenty of inflammatory lymphocytic aggregation. Significant elevations in liver function parameters (alanine aminotransferase and aspartate aminotransferase), mRNA expression levels of tumor necrosis factor-α, nicotinamide adenine dinucleotide phosphate oxidase and cyclooxygenase were detected as anti-inflammatory markers and 5-lipoxygenase, interleukin-1α and interleukin-6 as inflammatory biomarkers for liver and spleen, also significant elevations was detected in lipid peroxidation levels. The levels of antioxidants, glutathione, glutathione peroxidase, catalase and superoxide dismutase were significantly decreased.

CONCLUSION

our findings indicated that Fig fruit powder and olive protected against hepatic, renal and splenic injury induced with 2-NP in mice, especially if they were used in combination.

Development of reactive iron-coated natural filter media for treating antibiotic residual in swine wastewater: Mechanisms, intermediates and toxicity

Degradation mechanisms, surface phenomena, and the influence of co-existing organic matter on heterogeneous Fenton-like reactions were investigated using low-cost natural materials, to remove three veterinary antibiotics. Zeolite rock, laterite rock, and pumice rock were modified by adding ferric chloride. Fenton-like reactions yielded more than 50 % of antibiotic removal at a neutral pH. The modified zeolite exhibited the highest antibiotic removal efficiency. The heterogeneous Fenton-like reaction could be indicated by the simultaneous detection of Fe(II) and Fe(III) on the surface of the modified zeolite. Leaching iron was also observed to reduce the antibiotics with homogeneous Fenton-like reaction. The co-existing organic matter expressed by the COD below 400 mg/L did not have a considerable adverse impact on antibiotic removal. An H₂O₂ concentration as low as 20 μM was sufficient to react with the modified zeolite and degraded more than 70 % of the antibiotics at a neutral pH. The modified zeolite could be reused at least three times, with a removal efficiency of at least 80 %. The antibiotic degradation efficiencies in real treated swine wastewater were above 75 %. Moreover, the degradation intermediates and bacterial inhibition after treatment were investigated.

Innovative electrochemical biosensor for toxicological investigations on algae and cyanobacteria

An electrochemical biosensor is presented that directly reflects the metabolic activity of prokaryotic and eukaryotic cells. This biosensor can be used measure the biological activity of bacteria, yeasts and mammalian cells. This makes the sensor interesting for various applications in industry and science. A possible application is bioprocess control, monitor activities from yeasts, bacteria and fungi to increase the yield. Other applications are starter culture quality studies in the food industry and cytoxicological evaluation with mammalian cells. Our latest investigations additionally indicate the applicability of the electrochemical biosensor to measure algae and cyanobacteria. In our investigations, we were able to show that it was also possible to detect photosynthetic organisms with the electrochemical measurement method, used for investigations on prokaryotic and eukaryotic organisms before. Therefore, this the present study demonstrates an alternative to using this electrochemical biosensor equipped with alga and cyanobacteria for toxicological investigations based on selected test chemicals. The results of this study show a good correlation with those from reference methods, such as the Algal Growth Inhibition Test and the Microtox Test. The advantages of the new electrochemical biosensor are easy handling and shorter measurement time by using different types of test organisms. The evaluation of the sensor signal is based on the current-time curves of a potentiostatic measurement produced by the detection of microbially reduced mediator molecules immobilized in a gel structure. The mediator molecules are reduced during the measurement process. The reduced mediator molecules produce a current signal, which rapidly provides information about the vigor and vitality of living bacteria, yeasts, fungi or cells.

Application of (V)UV/O3 technology for post-treatment of biologically treated wastewater: A pilot-scale study

For the first time, high energy VUV photons and generation of O₃ by (V)UV lamps were applied together for removal of active pharmaceutical ingredients (APIs) from biologically treated wastewater (BTWW) in pilot-scale. The core of the pilot container unit was a photoreactor assembly consisting of six photoreactors, each containing a low-pressure Hg lamp (UV dose of 1.2 J/cm² and 6.6 J/cm² at 185 nm and 254 nm, respectively). BTWW was irradiated (4.75 min residence time) by (V)UV light in presence of in situ photochemically generated O₃ from coolant air of the lamps. Experiments were conducted at the site of two wastewater treatment plants. Out of seven target APIs (namely carbamazepine, ciprofloxacin, clarithromycin, diclofenac, metoprolol, sitagliptin, and sulfamethoxazole), 80-100% removal was accomplished for five and 40-80% for two compounds. Two degradation products of carbamazepine were detected. Degradation products of other target compounds were not found. The applied O₃ dose was 30-45 μg O₃/mg dissolved organic carbon. Inactivation of up to log-4.8, log-4.5 and log-3.8 could be achieved for total coliform, Escherichia coli and Enterococcus faecalis, respectively. SOS Chromotest indicated no genotoxicity nor acute toxicity. Generation of neither NH₄⁺, NO₂^- nor NO₃^- was observed during post-treatment. Electric energy per order values were calculated for the first time for (V)UV/O₃ treatment in BTWW with a median value of 1.5 kWh/m³. This technology can be proposed for post-treatment of BTWWs of small settlements or livestock farms to degrade micropollutants before water discharge or for production of irrigation water. Further studies are essential in pilot-scale for other applications.

Mutated Shiitake extracts inhibit melanin-producing neural crest-derived cells in zebrafish embryo

The ability of natural extracts to inhibit melanocyte activity is of great interest to researchers. This study evaluates and explores the ability of mutated Shiitake (A37) and wildtype Shiitake (WE) extract to inhibit this activity. Several properties such as total phenolic (TPC) and total flavonoid content (TFC), antioxidant activity, effect on cell and component profiling were conducted. While having no significant differences in total phenolic content, mutation resulted in A37 having a TFC content (1.04 ± 0.7 mg/100 ml) compared to WE (0.86 ± 0.9 mg/100 ml). Despite that, A37 extract has lower antioxidant activity (EC50, A37 = 549.6 ± 2.70 μg/ml) than WE (EC50 = 52.8 ± 1.19 μg/ml). Toxicity tests on zebrafish embryos show that both extracts, stop the embryogenesis process when the concentration used exceeds 900 μg/ml. Although both extracts showed pigmentation reduction in zebrafish embryos, A37 extract showed no effect on embryo heartbeat. Cell cycle studies revealed that WE significantly affect the cell cycle while A37 not. Further tests found that these extracts inhibit the phosphorylation of Glycogen synthase kinase 3 β (pGSK3β) in HS27 cell line, which may explain the activation of apoptosis in melanin-producing cells. It was found that from 19 known compounds, 14 compounds were present in both WE and A37 extracts. Interestingly, the presence of decitabine in A37 extract makes it very potential for use in the medical application such as treatment of melanoma, skin therapy and even cancer.

Effects on Apical Outcomes of Regulatory Relevance of Early-Life Stage Exposure of Double-Crested Cormorant Embryos to 4 Environmental Chemicals

Environmental risk assessment is often challenged by a lack of toxicity data for ecological species. The overall goal of the present study was to employ an avian early-life stage toxicity test to determine the effects of 4 chemicals (benzo[a]pyrene [BaP], chlorpyrifos, fluoxetine hydrochloride [FLX], and ethinyl estradiol [EE2]) on an ecologically relevant avian species, the double-crested cormorant (Phalacrocorax auritus), and to compare our results with those we previously reported for a laboratory model species, Japanese quail. Chemicals were dissolved in dimethyl sulfoxide and administered via air cell injection to fertilized, unincubated double-crested cormorant eggs at 3 nominal concentrations, the highest selected to approximate the 20% lethal dose. Of the 4 chemicals, only chlorpyrifos and FLX were detected in liver tissue of embryos at midincubation (day 14) and termination (day 26; 1-2 d prior to hatch); EE2 and BaP were not detectable, suggesting embryonic clearance/metabolism. No apical effects were observed in double-crested cormorant embryos up to the highest concentrations of chlorpyrifos (no-observed-effect level [NOEL] = 25 µg/g) or FLX (NOEL = 18 µg/g). Exposure to EE2 reduced embryonic viability and increased deformities at a concentration of 2.3 µg/g (NOEL = 0.18 µg/g), and BaP decreased embryonic viability (median lethal dose = 0.015 µg/g; NOEL = 0.0027 µg/g). Compared with Japanese quail, double-crested cormorant were more sensitive with regard to embryolethality and deformities for EE2 and embryolethality for BaP, whereas they were less sensitive to embryonic deformities associated with chlorpyrifos exposure. These data reinforce the idea that standardized toxicity tests using a laboratory model species may not always be protective of wild birds, and thus they stress the importance of developing such alternative testing strategies (e.g., the EcoToxChip Project) for ecologically relevant species to augment risk assessment efforts. Environ Toxicol Chem 2021;40:390-401. © 2020 SETAC.

Toxicity variability of urban road stormwater during storage processes in Shenzhen, China: Identification of primary toxicity contributors and implications for reuse safety

Urban road stormwater reuse is one of the most important ways to mitigate water resource shortage. Generally, stormwater is stored prior to reuse or further treatment. This study explored the stormwater toxicity variability during two types of storages, closed and open storages using Chinese hamster ovary cells (CHO), which are mammalian cells. The toxicity test by CHO cells can indirectly represent the risk related to human health. Both rainfall (without reaching ground surfaces) and urban road stormwater were collected to undertake laboratory-scaled storage experiments and basic water quality parameters (pH and dissolved oxygen), microorganisms (E.coli and total bacteria), total organic carbon and heavy metals (copper, Cu, zinc, Zn, nickel, Ni, chromium, Cr, cadmium, Cd and lead, Pb) were also investigated during storage processes. The outcomes showed that rainfall has a better water quality with lower toxicity than urban road stormwater (EC₅₀ values of rainfall were generally twice higher than road stormwater). Additionally, it is found that storing road stormwater for a certain period would reduce the toxicity and hence improve their reuse safety (EC₅₀ values in Day 1 were 10.30 mL and 8.46 mL for closed and open storage respectively while they were 14.3 mL and 13.0 mL in Day 7). Organic matters and Cu are important contributors of toxicity during both closed and open storages while bacteria is also essential in toxicity contribution in open storage. The research results implied that storing stormwater for a certain period has a benefit for reuse safety. This is related to cost-effectiveness in terms of treatment system design to avoid over engineering. Additionally, it is suggested that for reducing toxicity, the stormwater treatment designed before/after storage devices should focus on removal of organic matters and heavy metals (specially Cu) as well as restraining bacteria growth.

Characterization of sediment toxicity in Shanghai Harbor using toxicity tests and digital gene expression analysis based on clams Ruditapes phillipinarum

In the present study, chemical analysis of contaminants (three classes of organic pollutants and seven metals) and elutriate toxicity test were adopted to evaluate the potential environmental hazards of dredged sediment samples from five sites (SS1-5) along Huangpu River Channel (Shanghai Harbor, China). The metal Pb, Cu, Cr, Zn and the organic pollutants including total hexachlorocyclohexane (HCHs) and total dichlorodiphenyltrichloroethane (DDTs) in the five samples exceeded the threshold for effects level (TEL) to varying degrees. The probable effect concentration quotients (Q_PECm) of contaminants from the five dredged samples were all above 0.25, which means potential toxicity risks. Elutriate toxicity tests using medaka fish (Oryzias melastigma) and manila clam (Ruditapes philippinarum) showed that SS2 caused mortality to both species and SS1 caused mortality to fish. To explore the molecular biomarkers that may reflect the toxic effects, differential expressed genes were identified by RNA-Seq-based transcriptome profiling from the survived clams exposed to the two polluted elutriates (SS1, SS2). In clams exposed to SS1 and SS2 elutriate, 368 and 860 differential expressed genes (DEGs) were up-regulated, 199 and 1304 genes were down-regulated, respectively. Fourteen DEGs were selected from the enriched pathways that reflect cytotoxicity and responses to xenobiotics for the following quantitative real time PCR analysis. The transcriptomic profiling and the selected gene's expression patterns from clams exposed to SS1 and SS2 showed significant differences with the non-contaminated and control groups. Using the expression data of the selected gene battery in Factor Analysis allowed the discrimination between contaminated and non-contaminated sites and may reflect an influence gradient of sites. The development of the assay of these molecular biomarkers may provide a rapid and high-throughput tool for the quality assessment of the dredging sediments.

Can phytoplankton blooming be harmful to benthic organisms? The toxic influence of Anabaena sp. and Chlorella sp. on Chironomus riparius larvae

Cyanobacteria and microalgae are abundant biota groups in eutrophic freshwater ecosystems, serving as a food source for many aquatic organisms, including the larvae of non-biting midges (Chironomidae). Many species of cyanobacteria are toxin producers, which can act as stressors to other organisms. The present study aimed to analyze and compare the effects of dietary exposure to the common toxic cyanobacteria Anabaena sp. and non-toxic microalgae Chlorella sp. in Chironomus riparius larvae. Microcystin was detected and quantified in the methanolic extract of Anabaena sp. using the HPLC-DAD technique, and it was identified as microcystin-LR. Both Anabaena sp. and Chlorella sp. were suitable food sources to enable the survival of C. riparius larvae in laboratory conditions, causing negligible mortality and significant differences in the larval mass (ANOVA and Post hoc LSD test; p < 0.05) and hemoglobin concentration (Student's t-test; p < 0.05). Oxidative stress parameters such as advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS), catalase (CAT) and superoxide dismutase (SOD) activity, and DNA damage, were also investigated. One-way ANOVA, followed by the Post hoc LSD test, showed a significant increase in AOPP and CAT for the group of larvae fed with Chlorella sp. The same test showed moderate DNA damage in both groups of larvae, with greater damage in the group fed with Anabaena sp. Thus, Chlorella sp. and microcystin-LR producing Anabaena sp. are food sources that did not result in any drastic acute effect on the population level of C. riparius larvae. However, sub-individual-level endpoints revealed significant effects of the treatments, since they caused oxidative stress and DNA damage that may pose a danger to successive generations of test organisms.

Investigating toxicity of urban road deposited sediments using Chinese hamster ovary cells and Chlorella Pyrenoidosa

Road deposited sediments (RDS) is the key carrier of pollutants in the urban road stormwater processes and hence has been seen as an important pollutant source of urban road stormwater. Although many research studies have focused on RDS and pollutants attached to RDS, the investigation on RDS toxicity is very limited. Toxicity test can permit an overall assessment on whether the RDS polluted stormwater can be safely reused. This paper used two living organisms, namely Chinese hamster ovary (CHO) cells, (mammalian cells to indicate human health related toxicity) and Chlorella Pyrenoidosa (algae to indicate ecological health related toxicity) to test RDS toxicity by using an innovative "equivalent toxicity area (ETA)" approach. The outcomes showed that mammalian cells are more sensitive than algae in terms of RDS toxicity. Pb, Cd and Cr primarily contributed to mammalian cell-based toxicity while Zn, Ni, Cu and TOC are primarily toxic to algae. It is also found that road site characteristics such as land uses exerted an important influence on RDS toxicity. Commercial areas tended to generate RDS with higher human health risk related toxicity while industrial areas had a potential to produce RDS with high ecological health risk related toxicity. The research outcomes also showed that solely focusing on pollutant themselves on RDS can not accurately indicate RDS pollution. An approach to considering both pollutant loads and toxicity is preferred. These results were expected to provide a useful insight to enhancing effectiveness of RDS polluted urban road stormwater management and ensuring their reuse safety.

Embryo bioassays with aquatic animals for toxicity testing and hazard assessment of emerging pollutants: A review

This review article gathers the available information on the use of embryo-tests as high-throughput tools for toxicity screening, hazard assessment and prioritization of new and existing chemical compounds. The approach is contextualized considering the new legal trends for animal experimentation, fostering the 3R policy, with reduction of experimental animals, addressing the potential of embryo-tests as high-throughput toxicity screening and prioritizing tools. Further, the current test guidelines, such as the ones provided by OECD and EPA, focus mainly in a limited number of animal lineages, particularly vertebrates and arthropods. To extrapolate hazard assessment to the ecosystem scale, a larger diversity of taxa should be tested. The use of new experimental animal models in toxicity testing, from a representative set of taxa, was thoroughly revised and discussed in this review. Here, we critically review current tools and the main advantages and drawbacks of different animal models and set researcher priorities.

Acetaminophen affects the survivor, pigmentation and development of craniofacial structures in zebrafish (Danio rerio) embryos

In spite of its toxic effects, N-acetyl-p-aminophenol (APAP), also commonly known as acetaminophen or paracetamol, is one of the most widely used analgesic and antipyretic agents. It can be obtained without a medical prescription. To test the effect over the zebrafish embryonic development, a Fish Embryo acute Toxicity (FET) test was carried out with acetaminophen to establish the range of concentrations that cause a harmful effect on the zebrafish development. Diminished pigmentation (in embryos treated from 0 h post-fertilization) and blockage of melanin synthesis (in larvae treated from 72 h post-fertilization) were detected, suggesting the involvement of this compound in the development of black pigment cells as described recently for human epidermal melanocytes. Morphological abnormalities such as aberrant craniofacial structures, pericardial edemas, and blood accumulation were also found. All these effects could be due to higher levels of apoptotic cells detected in treated embryos. Therefore, teratogenic effects of acetaminophen cannot be ruled out, and its wide use should be taken with caution.

De novo biosynthesis of 8-hydroxyoctanoic acid via a medium-chain length specific fatty acid synthase and cytochrome P450 in Saccharomyces cerevisiae

Terminally hydroxylated fatty acids or dicarboxylic acids are industrially relevant compounds with broad applications. Here, we present the proof of principle for the de novo biosynthesis of 8-hydroxyoctanoic acid from glucose and ethanol in the yeast Saccharomyces cerevisiae. Toxicity tests with medium-chain length ω-hydroxy fatty acids and dicarboxylic acids revealed little or no growth impairments on yeast cultures even at higher concentrations. The ability of various heterologous cytochrome P450 enzymes in combination with their cognate reductases for ω-hydroxylation of externally fed octanoic acid were compared. Finally, the most efficient P450 enzyme system was expressed in a yeast strain, whose fatty acid synthase was engineered for octanoic acid production, resulting in de novo biosynthesis of 8-hydroxyoctanoic acid up to 3 ​mg/l. Accumulation of octanoic acid revealed that cytochromes P450 activities were limiting 8-hydroxyoctanoic acid synthesis. The hydroxylation of both externally added and intracellularly produced octanoic acid was strongly dependent on the carbon source used, with ethanol being preferred. We further identified the availability of heme, a cofactor needed for P450 activity, as a limiting factor of 8-hydroxyoctanoic acid biosynthesis.

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Low toxic effects of medium-chain ω-hydroxy fatty acids on yeast cells .

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Systematic comparison of cytochrome P450 enzyme activities on octanoic acid .

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De novo biosynthesis of 8-hydroxyoctanoic acid .

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Improvement of cytochrome P450 activity with ethanol or by addition of hemin .

Advanced oxidation processes applied for color removal of textile effluent using a home-made peroxidase from rice bran

Enzymes are becoming tools in industrial processes because of several advantages, including activity in mild environmental conditions, and high specificity. Peroxidase, for one, stably oxidizes several substrates. The present study aimed to develop advanced oxidation processes (AOP), using non-commercial rice bran peroxidase to remove color and toxicity of synthetic textile wastewater. Using a microwave and shaker system, we obtained 38.9% and 100% of effluent color removal after peroxidase treatment, respectively. In addition, the shaker system decants residual dye particles through filtration, providing the textile industry with an economical and environmentally viable alternative to effluent treatment. In toxicity tests results, both treatment systems damaged the used genetic material. This damage occurs because of industrial discharge of wastewater into water bodies; effluent dilution reduced this damage. The data suggest that peroxidase as a textile effluent treatment has potential uses in industrial processes, because rice bran peroxidase has demonstrated affinity with dyes.

The addition of a quaternary group in biopolymeric material increases the adsorptive capacity of Acid Blue 25 textile dye

The quaternization of chitosan molecules creates materials with high adsorptive capacity towards textile dyes, which renders them capable of rapidly removing such dyes from a solution. In this study, a novel material was synthesized in bead form to adsorb the Acid Blue 25 textile dye. The adsorption isotherms, kinetics, and thermodynamics of this new material were investigated. The beads were further characterized by FT-IR and SEM studies, as well as their rheological behavior. Bioassays with Daphnia similis analyzed the toxicity of the dye before and after treatments. The Freundlich isotherm model fitted to all the adsorption data in a pH range from 2.50 to 8.50. Kinetic studies showed that adsorption was ruled by an intraparticle diffusion process and reached equilibrium in 270 min, as 39.527 μg mg^-1 of dye was sorbed to the beads. Thermodynamic studies showed that adsorption was a spontaneous and endothermic process. Thermodynamics also confirmed that the adsorption was proportionally influenced by higher temperatures. The FT-IR spectroscopy identified the adsorbate/adsorbent binding sites, thus confirming the occurrence of chemisorption. Post-treatment bioassays found a significant decrease in toxicity, obtaining just 10% of D. similis mortality after adsorption treatments. Therefore, the synthesized beads from this research can potentially be applied to the treatment of textile effluents.

Toxicity of crude organic extracts from the zoanthid Palythoa caribaeorum: A biogeography approach

Marine isolates such as palytoxin (PTX) are of concern within the Caribbean region due to their toxicity. PTX for example has been described as a one of the most known potent marine toxins, known to prevent predation from larger species (e.g. vertebrates) as well as the prevention of being overgrown from other coral species. PTX is a polyhydroxylated polyether toxin with a very large and complex chemical structure that possesses both hydrophilic and lipophilic properties. Previous acute toxicity tests using brine shrimp (Artemia salina) and PTX extract had shown it to be moderately toxic. In humans, PTX has been credited to be responsible for extreme symptoms such anaphylactic shock, rapid cardiac failure and eventual death occurring within minutes. Extrapolation for human dose ranges has therefore been suggested to be between 2.3 and 31.5 μg. This study isolates a potentially PTX-enriched extract from Palythoa caribaeorum and examines its organic extract toxicity from a biogeography perspective from a within-colony to a variety of reef sites around Trinidad and Tobago that are popular for marine visitors. This research represents an acute study with a high level of crude organic extract toxicity on A. salina whilst postulating potential factors which may contribute to its extreme toxicity and the risk posed to users of these environments.

Toxicity of exogenous antimony to the soil-dwelling springtail Folsomia candida

Antimony (Sb) is a toxic pollutant, but data for Sb toxicity to springtails in soil are limited, and the effects of Sb speciation, soil physiochemical properties, and aging time on Sb toxicity have not been investigated. To address this, the effects of Sb on Folsomia candida were evaluated in laboratory studies. The results demonstrated that compared with Sb(III), no significant change in mortality was observed in Sb(V)-treated soil, but the EC₅₀ value for the reproduction was 28-fold higher than that of Sb(III). Sb(III) toxicity was very different in four soils. The LC₅₀ values for the survival were 2325-5107 mg kg^-1 in the acute test and 605-2682 mg kg^-1 in the chronic test, and the EC₅₀ values for the reproduction were 293-2317 mg kg^-1. The toxicity discrepancies were associated with the variations in oxidation potential and sorption capacity among corresponding soils. Toxicity significantly positively correlated with the clay and amorphous iron content but significantly negatively correlated with pH. Long-term aging markedly decreased Sb(III) toxicity, and the EC₅₀ and LC₅₀ values were unexpectedly higher than the highest test concentration in soil aged for 180 days. Sb(III) toxicity was probably modified more by oxidation than by changes in the available Sb fraction during aging.

Effects of s-metolachlor on early life stages of marbled crayfish

The effects of s-metolachlor chronic exposure at concentrations of 1.1 μg/L (maximal real environmental concentration in the Czech Republic), 11 μg/L (environmental relevant concentration) and 110 μg/L on early life stages of marbled crayfish (Procambarus virginalis) was evaluated under laboratory conditions. All s-metolachlor exposures resulted in higher mortality, delay ontogenetic development with accompanied slower growth and excited behaviour (increase of total distance moved and walking speed). Significantly lower superoxide dismutase, catalase, glutathione S-transferase activity and reduced glutathione level was observed at two higher tested concentrations (11 and 110 μg/L) of s-metolachlor compared with the control. S-metolachlor in concentrations 110 μg/L showed alteration of the tubular system of hepatopancreas including focal disintegration of tubular epithelium and notable reduction in epithelial cells number, especially B-cells. In conclusion, potential risk associated with using of s-metolachlor in agriculture, due to effects on non-target aquatic organisms as documented on early life stages of marbled crayfish in this study, should be taken into account.

Catalytic wet air oxidation of Reactive Black 5 in the presence of LaNiO3 perovskite catalyst as a green process for azo dye removal

The removal of textile azo dye, Reactive Black from the aqueous solutions by catalytic wet air oxidation in the presence of LaNiO₃ perovskite catalyst has been investigated. The most suitable reaction conditions were determined by testing various the catalyst loadings, reaction temperature and pressure values, and the initial pH of the Reactive Black 5 solutions. The most suitable reaction conditions with 0.61 L/min of air flow rate were found to be 1 g/L of LaNiO₃ loading, 50 °C of reaction temperature, 1 atm of reaction pressure, and, pH = 3 for the oxidation of 100 mg/L Reactive Black solutions. Under these conditions the degradation and the decolorization efficiencies were evaluated as 65.4% and 89.6%, respectively. The phytotoxicity analyzes were carried out by using Lepidium sativum. According to the toxicity tests a remarkable decrease in the growth inhibition was achieved by the catalytic wet air oxidation in the presence of LaNiO₃ catalyst. The growth inhibition in the untreated and treated dye solutions were calculated as 49.3% and 23.7%, respectively.

The impact of kraft pulping effluent on egg survival and hatching success in two species of Clupeiformes (Teleostei)

The anchoveta (Engraulis ringens) and sardine (Strangomera bentincki) are coastal pelagic species with important spawning areas off the coast of Chile. The discharge of secondary-treated effluents from a kraft pulp plant near one of these spawning areas has raised environmental concerns. Therefore, effluent effects on the development of anchoveta and sardine eggs were assessed by in vitro exposure. Eggs were sampled between 2007 and 2010 off Talcahuano, Chile. Subsequent toxicity tests (96 h duration, 12 °C) were performed using increasing effluent concentrations, a filtered seawater control, and two potassium dichromate concentrations (to verify consistent embryonic sensitivity). Egg mortality and hatching success were evaluated. For anchoveta, mortality (9.9 ± 7.1%) did not significantly differ among groups in five toxicity tests except the final toxicity test that showed significant differences in mortality (5.6% control vs 27.8% in 100% effluent). For sardines, no differences in mortality existed between the effluent dilutions (2.6 ± 3.6%) and control (6.3 ± 3.9%). Notably, anchoveta egg survival and hatching success rates were inconsistent, i.e., the highest rates of hatching failure occurred on the same sampling date with the highest rates of survival for the 100% effluent group (72%). In conclusion, the obtained results indicate that (i) anchoveta egg mortality and hatching failure increase only under 100% effluent exposure, coinciding with decreased egg quality near the end of spawning season and (ii) high effluent dilutions not significantly increase sardine and anchoveta egg mortalities. Nevertheless, the recorded adverse effects to the hatching process should be studied in greater detail, particularly considering interspecific variability and the complexity of reproductive processes, especially during early development.

Acute Lethal Toxicity of Heavy Metals to the Seeds of Plants of High Importance to Humans

Laboratory experiments were conducted to assess the effects of highly toxic and dangerous metals (Pb, Cd, Hg) and essential microelements (Cr, Cu, Ni, Zn) on the seed germination process in vetch and eight plant species of major importance to human consumption. The degree of metal toxicity was determined on the basis of acute LC50 values calculated by means of two different methods. All the metals were found to inhibit the germination process, but in a varying, species-dependent degree. Of all the plant seeds under study, the most sensitive to the presence of the examined metals during germination were the seeds of cress (Cu, Pb, Hg), rye (Ni, Zn, Cd) and barley (Cr), while vetch (Cr, Ni, Zn, Cd, Pb, Hg), rape (Cr, Cu) and pea (Ni, Cd) were found to be least affected.

An enhanced bioindicator for calorimetric monitoring of prophage-activating chemicals in the trace concentration range

Viruses that infect bacteria (bacteriophages) can either lyse bacteria directly or integrate their genome into the bacterial genome. In the latter case, the viral genome (called prophage) remains dormant, and both phages and bacteria are able to survive in this state. But the silent prophages can be reactivated by, e.g., chemicals, accompanied by the release of substantial quantities of phage particles that further infect other phage-sensitive bacteria, thus harming ecosystems or technical systems by way of a viral bloom. Recently, a calorimetric method was developed to monitor the prophage-activating properties of chemicals. The method evaluates the difference in the metabolic heat of the Escherichia coli bioindicator with (λ+) and without (λ-) lambda prophages under the influence of the test substances. Simulations and experiments clearly demonstrate that the sensitivity of the test can be significantly improved, when a customized mixture of λ+ and λ- E. coli strains is used for enhanced bioindication. Hence, the new method mirrors a common situation in nature, where bacteria with and without prophages coexist. In summary, a monitoring method is suggested that provides quick results (after few hours) and offers both the option for automation with low workload (requires only a few minutes) and usage of commercially available instruments.

Pilot scale aided-phytoremediation of a co-contaminated soil

A pilot scale experiment was conducted to investigate the aided-phytoextraction of metals and the aided-phytodegradation of petroleum hydrocarbons (PHC) in a co-contaminated soil. First, this soil was amended with compost (10% w/w) and assembled into piles (Unp-10%C). Then, a phyto-cap of Medicago sativa L. either in monoculture (MS-10%C) or co-cropped with Helianthus annuus L. as companion planting (MSHA-10%C) was sown on the topsoil. Physico-chemical parameters and contaminants in the soil and its leachates were measured at the beginning and the end of the first growth season (after five months). In parallel, residual soil ecotoxicity was assessed using the plant species Lepidium sativum L. and the earthworm Eisenia fetida Savigny, 1826, while the leachate ecotoxicity was assessed using Lemna minor L. After 5months, PH C10-C40, PAH-L, PAH-M PAH-H, Pb and Cu concentrations in the MS-10%C soil were significantly reduced as compared to the Unp-10%C soil. Metal uptake by alfalfa was low but their translocation to shoots was high for Mn, Cr, Co and Zn (transfer factor (TF) >1), except for Cu and Pb. Alfalfa in monoculture reduced electrical conductivity, total organic C and Cu concentration in the leachate while pH and dissolved oxygen increased. Alfalfa co-planting with sunflower did not affect the extraction of inorganic contaminants from the soil, the PAH (M and H) degradation and was less efficient for PH C10-C40 and PAH-L as compared to alfalfa monoculture. The co-planting reduced shoot and root Pb concentrations. The residual soil ecotoxicity after 5months showed a positive effect of co-planting on L. sativum shoot dry weight (DW) yield. However, high contaminant concentrations in soil and leachate still inhibited the L. sativum root DW yield, earthworm development, and L. minor growth rate.

Preparation and toxicity evaluation of a novel nattokinase-tauroursodeoxycholate complex

Nattokinase (NK), which has been identified as a potent fibrinolytic protease, has remarkable potential in treatment of thrombolysis, and even has the ability to ameliorate chronic vein thrombosis. To reduce the hemorrhagic risk from an intravenous injection of NK, nattokinase-tauroursodeoxycholate (NK-TUDCA) complex was prepared at different pH values and with different ratios of NK and TUDCA. When assessing survival time, survival state, tail injury, and the body weight of mice, it was found that the NK-TUDCA complex (NK: 10 kIU/ml; TUDCA: 10 mg/ml; pH 5.0) had a lower toxicity when administered at an NK dosage of 130 kIU/kg in the acute toxicity test and 13 kIU/kg in the repeated low-dose challenge. From the results of the in vitro thrombolytic test and characterization of NK-TUDCA, we speculated that the delayed release of NK-TUDCA might be the main cause of toxicity reduction by the complex. This study described the preparation of an NK complex with low toxicity following intravenous administration, which could be utilized for further clinical study of NK.

Biochemical alterations in duckweed and algae induced by carrier solvents: Selection of an appropriate solvent in toxicity testing

Carrier solvents are often used in aquatic toxicity testing for test chemicals with hydrophobic properties. However, the knowledge of solvent effects on test organisms remains limited. The present study aimed to determine the biochemical effects of the 4 common solvents methanol, ethanol, acetone, and dimethyl sulfoxide (DMSO) on 2 test species, Lemna minor and Raphidocelis subcapitata, by applying Fourier transform infrared spectroscopy (FTIR) coupled with multivariate analysis to select appropriate solvents for toxicity testing. The results showed biochemical variations associated with solvent treatments at different doses on test species. From the infrared spectra obtained, the structures of lipid membrane and protein phosphorylation in the test species were found to be sensitive to the solvents. Methanol and ethanol mainly affected the protein secondary structure, whereas acetone and DMSO primarily induced alterations in carbohydrates and proteins in the test species. The FTIR results demonstrated that methanol and ethanol showed higher biochemical alterations in the test species than acetone and DMSO, especially at the high doses (0.1 and 1% v/v). Based on the growth inhibition displayed and FTIR spectroscopy, acetone, and DMSO can be used as carrier solvents in toxicity testing when their doses are lower than 0.1% v/v. Environ Toxicol Chem 2017;36:2631-2639. © 2017 SETAC.

Effects of three triazine metabolites and their mixture at environmentally relevant concentrations on early life stages of marbled crayfish (Procambarus fallax f. virginalis)

The sensitivity of early life stages of marbled crayfish (Procambarus fallax f. virginalis) to chronic exposure of one out of three triazine metabolites (terbuthylazine 2-hydroxy - T2H, terbuthylazine-desethyl - TD, and atrazine 2-hydroxy - A2H) and their mixture at maximal environmentally real concentrations was evaluated under laboratory conditions. The effects were assessed on the basis of mortality, growth, development, oxidative stress biomarkers, antioxidant enzymes activity and histopathology. Single metabolites (T2H - 0.73 μg/L; TD - 1.80 μg/L; A2H - 0.66 μg/L) and their mixture were not associated with negative effects on mortality, behaviour and early ontogeny, however, two metabolites (TD and A2H) and mixtures caused significantly lower growth and significantly higher catalase activity of early life stages of marbled crayfish. No histopathological changes of gills were observed after exposure to all tested triazine treatments, however, apparent histological differences in structural cells organization such as superiority in numbers of lipid resorptive cells were recorded in after exposition to TD and mixture. In conclusion, this study shows potential risk of using triazine herbicides in agriculture due to effects of their degradation products on non-target organisms.

Prediction of hepatotoxicity for drugs using human pluripotent stem cell-derived hepatocytes

Drug-induced liver toxicity is a main reason for withdrawals of new drugs in late clinical phases and post-launch of the drugs. Thus, hepatotoxicity screening of drug candidates in pre-clinical stage is important for reducing drug attrition rates during the clinical development process. Here, we show commercially available hepatocytes that could be used for early toxicity evaluation of drug candidates. From our hepatic differentiation technology, we obtained highly pure (≥98%) hepatocytes from human embryonic stem cells (hESCs) having mature phenotypes and similar gene expression profiles with those of primary human tissues. Furthermore, we optimized 96-well culture condition of hESC-derived hepatocytes suitable for toxicity tests in vitro. To this end, we demonstrated the efficacy of our optimized hepatocyte model for predicting hepatotoxicity against the Chinese herbal medicines and showed that toxicity patterns from our hepatocyte model was similar to those of human primary cultured hepatocytes. We conclude that toxicity test using our hepatocyte model could be a good alternative cell source for pre-clinical study to predict potential hepatotoxicity in drug discovery industries.

Fourier-transform infrared spectroscopy as a novel approach to providing effect-based endpoints in duckweed toxicity testing

Traditional duckweed toxicity tests only measure plant growth inhibition as an endpoint, with limited effects-based data. The present study aimed to investigate whether Fourier-transform infrared (FTIR) spectroscopy could enhance the duckweed (Lemna minor L.) toxicity test. Four chemicals (Cu, Cd, atrazine, and acetochlor) and 4 metal-containing industrial wastewater samples were tested. After exposure of duckweed to the chemicals, standard toxicity endpoints (frond number and chlorophyll content) were determined; the fronds were also interrogated using FTIR spectroscopy under optimized test conditions. Biochemical alterations associated with each treatment were assessed and further analyzed by multivariate analysis. The results showed that comparable x% of effective concentration (ECx) values could be achieved based on FTIR spectroscopy in comparison with those based on traditional toxicity endpoints. Biochemical alterations associated with different doses of toxicant were mainly attributed to lipid, protein, nucleic acid, and carbohydrate structural changes, which helped to explain toxic mechanisms. With the help of multivariate analysis, separation of clusters related to different exposure doses could be achieved. The present study is the first to show successful application of FTIR spectroscopy in standard duckweed toxicity tests with biochemical alterations as new endpoints. Environ Toxicol Chem 2017;36:346-353. © 2016 SETAC.