Toxicity Values Research Articles

Distribution of 26 Metals in the Waters of the Aquatic Ecosystems of the Cotonou Channel and Lake Nokoué, Benin

Metallic elements have various origins: natural and anthropogenic sources as geochemical, marine and atmospheric sources resulting from the fallout of pollutants emitted or dust raised and which are transported by water and air currents. Thus marine, brackish and fresh continental waters may have high metal concentrations. In addition, some essential metals can become toxic above certain concentration values in aquatic environments. The aquatic ecosystems of Cotonou channel and lake Nokoué receive the pollutants charges from the town cities of Cotonou, Abomey-Calavi and town hall of So Ava. The aim of this study is to analyze waters from Eighteen (18) stations identified in the two ecosystems (nine by ecosystem). The concentrations of magnesium (Mg), calcium (Ca), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), beryllium (Be), aluminum (Al), strontium (Sr), molybdenum (Mo), silver (Ag), tin (Sn), barium (Ba), platinum (Pt), mercury (Hg), thallium (Tl), lead (Pb), thorium (Th) and uranium (U) were measured after acid digestion of the water samples using the inductively coupled plasma source mass spectrometer (ICP-MS). The results of the analyses indicate an unequal distribution of metals in the different ecosystems. However, atypical concentrations were observed at some stations of the lake and the channel. Magnesium, calcium and manganese have very high values in Lake Nokoué respectively at Ganvié market station GAN_M (2990 ± 105 mg/L), Ganvié center, station GAN_C (4991 ± 177 mg/L) and Lake middle station MLak4 (10662 ± 17.03 μg/L). On the other hand, iron, aluminum and strontium have very high concentrations in the Cotonou Channel respectively at Agbato station AGB (5236 ± 103 and 8289 ± 519 μg/L) and at the estuary station EST (6118 ± 68 μg/L). The concentrations were compared to wells and cborehole waters in sixth neighborhood of Cotonou. We have used statistical analyzers such as MANOVA which have made it possible to classify the waters and metals in the ecosystems studied compared to groundwater and Well water waters. We use hierarchical clustering on principal components to identify similarities between stations based on metal concentration with R software packages “FactoMineR” and “factoextra”. In general, we can conclude that most of the metals have an anthropogenic source except strontium and major elements (Ca and Mg) which could respectively provide from marine waters and geochemical sources.

The potential ecological risk of veterinary pharmaceuticals from swine wastewater on freshwater aquatic environment

The impact of pharmaceutical residue transport in the aquatic ecosystem has become an increasing subject of environmental interest due to the inherent bioactivity of trace levels of antibiotics and the negative environmental and public health impact. In this study, three veterinary pharmaceuticals including tetracycline, ivermectin, and salicylic acid were investigated in a piggery effluent from Western Cape, South Africa. Three freshwater organisms' taxonomic groups (Pseudokirchneriella subcapitata, Daphnia magna, and Tetrahymena thermophila) were used to determine the ecological risk of different treated piggery effluent concentration range of 1%, 10%, and 20% and a cocktail mixture of veterinary pharmaceuticals of environmental concerns. The average concentration of veterinary pharmaceuticals was in the range of 47.35, 7.19, and 1.46 μg L-1 for salicylic acid, chloro-tetracycline, and ivermectin, respectively. P.subcapitata exposed to 20% piggery wastewater effluent at 24- and 48-h EC50 showed a toxicity value of 14.2% and 13.6% (v/v), respectively. The study established the ecological risk of the test compounds as low to medium risk for low-level dose and low concentrations of piggery effluent. The relative sensitivity ranking of the taxa drawn is microalgae > protozoa > Cladocera. The study results demonstrated that a high dose of piggery effluent and mixtures of veterinary pharmaceutical can pose a high risk in freshwater ecosystems. PRACTITIONER POINTS: Transport processes of veterinary antibiotics into the environment were investigated. Dilution effect of the veterinary pharmaceutical on the antibiotic levels exists. High dose of piggery effluent presented an ecological risk.

Toxicidade e sinergismo de óleo essencial de Piper aduncum L. em populações de Sitophilus zeamais (Coleoptera: Curculionidae)

ABSTRACT Researches on the use of essential oil of Piper aduncum L. (EOPA) as a synergist in stored grain pests are still incipient. This study aimed to determine the toxicity of deltamethrin and EOPA, as well as to study the effect of the binary mixture of EOPA + deltamethrin, on five Sitophilus zeamais Brazilian populations. The toxicity was investigated based on concentration-mortality data from deltamethrin and EOPA in thirteen S. zeamais populations. The standard susceptibility population of ¼ LC20 was used with the deltamethrin combinations to generate lethal concentrations capable of causing 50 and 95 % of mortality (LC50 and LC95). A binary mixture of EOPA x deltamethrin was also tested in five S. zeamais populations to detect the synergistic effect with the deltamethrin. The concentration-mortality curves were generated, and the residual toxicity values after 24 h of exposure ranged 0.003-0.08 µL cm-2 for deltamethrin, 0.04-2.038 µL cm-2 for EOPA and 0.0016-0.014 µL cm-2 for the binary mixture. The S. zeamais populations showed an uneven toxicity in response to the deltamethrin. The Jacarezinho (Paraná state) population showed resistance, with toxicity ratios for LC50 increasing by 3.06 and 4.13 times, when compared to susceptible populations, for EOPA and deltamethrin, respectively. The Barbacena (Minas Gerais state) population was considered as the susceptibility standard in the EOPA toxicity bioassays. The binary mixture suppressed the resistance mechanism of the tested S. zeamais populations due to the synergistic action of the bioinsecticide with the deltamethrin.

The in silico and toxicity study of fraction red betel leaf (Piper crocatum) extract on histology lymphoid organ and hepatopancreas in white shrimp (Litopanaeus vannamei)

The shrimp farming industry has experienced a high mortality caused by diseases in recent decades. One of the most common diseases is vibriosis. This research aims is to obtain information on compounds found in fraction one of Piper crocatum as a therapeutic agent using in silico prediction and evaluate the toxicity test with an LC50. The potential of active ingredient content from P. crocatum extract was analyzed by in silico methods. The LC50 test was conducted by injections of the fraction one extract of P. crocatum for 96 hours at doses of 0 (control), 2 μg/g, 4 μg/g, 6 μg/g, 8 μg/g, and 10 μg/g. In silico toxicity (LD50) analysis showed that citral had the highest toxicity value (LD50) at 500 mg/kg and was classified as toxicity class 4, with an abundance value of 3.71%. The 10 μg/g concentration showed an LC50 mortality value of 53.3±5.8%. The percentage of heavy damage was observed at the concentration of 10 μg/g (53.33). These results indicate that the higher the concentration of fraction one extract of P. crocatum, the higher the percentage of damage to white shrimp's hepatopancreas and lymphoid organs.

In vivo Study of Chalcone Loaded Carbon Dots for Enhancement of Anticancer and Bioimaging Potencies.

The fluorescent imaging and drug delivery utilizing carbon dots nanomaterials (CDs) have attracted tremendously due to their unique optical ability and outstanding biocompatibility. Herein, we reported a new design of chalcone-loaded carbon dots (Chalcone-APBA-CDs) to serve chalcone transport onto cancer cells and enhance the CDs bioimaging and antitumor activity. The boronic acid was directly introduced to carbon dots (CDs) via pyrolysis process to drive CDs specifically to the cancer cell, and chalcone was mediated on CDs by ultrasonication to perform facile release of the drug delivery model. The successfully synthesized Chalcone-APBA-CDs were proved by their chemical structure, fluorescent activities, in vitro and in vivo analyses, and drug release systems using different pH. In addition, flow cytometry and confocal fluorescent imaging proved CDs' cellular uptake and imaging performance. In vitro analyses further proved that the Chalcone-APBA-CDs exhibited a higher toxicity value than bare CDs and efficiently inhibited the proliferation of the HeLa cells depending on their dose-response. Finally, the performance of Chalcone-APBA-CDs on cancer healing capability was examined in vivo with fibrosarcoma cancer-bearing mice, which showed a remarkable ability to reduce the tumor volume compared with saline (control). This result strongly suggested that the Chalcone-APBA-CDs appear promising simultaneously as cancer cell imaging and drug delivery.

Screening potential toxicity of currently used herbicides in the freshwater amphipod Gammarus fossarum based on multi-level biomarker responses to field-realistic exposures

Herbicides are widely used to control weeds and maximize crop growth. Because of agricultural runoff, these chemicals are potentially hazardous to aquatic wildlife. However, their ecotoxicity and resulting disturbance in individual performance remain scarcely documented in freshwater crustaceans. This study aimed to screen the potential toxicity of currently used herbicides in the ecosystem engineer Gammarus fossarum using multi-level biomarkers. In microcosms, gammarids were exposed for 72 h to 12 herbicides individually (quinmerac, mesotrione, bentazone, isoproturon, chlortoluron, metazachlor, chloridazone, diflufenican, flufenacet, aclonifen, prosulfocarb and metolachlor) at a field-realistic concentration (i.e. 10 μg/L). The sublethal effects were assessed by monitoring several biochemical, physiological and behavioural traits. In exposed gammarids, alterations in behavioural activities were observed, i.e. increased locomotion and respiration as a general trend. Moreover, biochemical biomarkers suggested herbicide-dependent disruptions in moulting, antioxidant responses and cell integrity. Integrating multi-metric variations through statistical analyses allowed us to identify herbicide clusters likely to trigger common sets of biological responses. Depressed antioxidant defence at the cell level and impaired respiration at the individual level were the predominant toxic effects of herbicides, related to their hydrophobic feature. Furthermore, establishing relationships between sublethal alterations in gammarids and acute lethality or chronic toxicity values defined for regulatory purposes supports the relevance of these alterations as early warnings of toxicity. Our findings demonstrate that currently used herbicides have unexpected toxicological effects in a non-target wild animal, with possible long-term alterations in population dynamics and associated ecological functions, which constitute promising diagnostic tools for risk assessment in agricultural areas.

Establishing a Robust and Reliable Response from a Potent Osmium-Based Photosensitizer Via Lipid Nanoformulation†.

Osmium (Os) based photosensitizers (PSs) are a unique class of nontetrapyrrolic metal-containing PSs that absorb red light. We recently reported a highly potent Os(II) PS, rac-[Os(phen)2 (IP-4T)](Cl)2 , referred to as ML18J03 herein, with light EC50 values as low as 20 pm. ML18J03 also exhibits low dark toxicity and submicromolar light EC50 values in hypoxia in some cell lines. However, owing to its longer oligothiophene chain, ML18J03 is not completely water soluble and forms 1-2 μm sized aggregates in PBS containing 1% DMSO. This aggregation causes variability in PDT efficacy between assays and thus unreliable and irreproducible reports of invitro activity. To that end, we utilized PEG-modified DPPC liposomes (138 nm diameter) and DSPE-mPEG2000 micelles (10.2 nm diameter) as lipid nanoformulation vehicles to mitigate aggregation of ML18J03 and found that the spectroscopic properties important to biological activity were maintained or improved. Importantly, the lipid formulations decreased the interassay variance between the EC50 values by almost 20-fold, with respect to the unformulated ML18J03 when using broadband visible light excitation (P =0.0276). Herein, lipid formulations are presented as reliable platforms for more accurate invitro photocytotoxicity quantification for PSs prone to aggregation (such as ML18J03) and will be useful for assessing their invivo PDT effects.

COMPARATIVE STUDY OF IN-VITRO TOXICITY OF RAW HONEY AND FERMENTED HONEY USING THE BSLT (BRINE SHRIMP LETHALITY TEST) METHOD

Honey is an alternative product used in traditional medicine because of concerns, honey is a sweet liquid made by bees using flower nectar. Raw honey has low water content and high sugar content, when the water content in honey is high it makes honey easy to ferment. The samples used were raw honey and fermented honey. Raw and fermented honey contains phenolic compounds that can act as anticancer candidates by testing anticancer compounds in the form of toxicity measurements using the BSLT method. The honey sample yielded a toxicity of 59.75 μg/mL. While the fermented honey sample obtained an LC50 value of 3.28 μg/mL, which means the LC50 value was 30 ppm, indicating that the fermented honey sample was included in the very toxic category. Toxicity test on raw honey samples showed the LC50 value was in the toxic range. In the toxicity test, the fermented honey sample showed an LC50 value of 30 ppm, which means that the fermented honey has a very toxic toxicity value. There are differences in LC50 values in the second sample. However, statistically, there is no significant difference between raw honey and fermented honey

Haloacetonitrile stability in cell culture media used in vitro toxicological studies

Haloacetonitriles (HANs) are an emerging class of nitrogenous disinfection by-products (DBPs) formed in disinfected drinking water and have been reported to be more cyto- and genotoxic than the regulated DBPs. HANs are also known to hydrolyze under neutral pH and normal room temperature. However, the stability of HANs has not been well characterized in DBP toxicological assessments. Most toxicological assessments expose DBPs up to several days which may result in a mixture of HANs and degradation products that might have underestimated HAN toxicity. In this study, HANs stability was characterized in 1) a buffer solution in sealed vials, 2) cell culture media (CCM) in sealed vials, and 3) CCM in 96 sealed well plates with 5% CO2. Solutions were incubated at 37 °C for 3 days. MonoHANs were found to be stable in buffer and CCM except when HANs were incubated in CCM in plates where they could possibly be affected by volatilization and photodegradation during sample handling. However, di- and tri- HANs degraded between 70 and 100% in both buffer solution and CCM. They were also found to be less stable in CCM than in buffer solution possibly from HANs reacting with nucleophiles present in CCM (i.e., amino acids). Identified degradation products include corresponding haloacetamides and haloacetic acids for buffer solutions and only haloacetic acids and an unknown brominated compound for CCM. Results of this study suggests that reported toxicity values might have been underestimated and should consider changing CCM and DBP on a daily basis for a more accurate toxicity measurement.

An FeP/carbon composite derived from a phytic acid-Fe3+ complex for sulfathiazole degradation through peroxymonosulfate activation

Peroxymonosulfate (PMS) activation-based advanced oxidation technology possesses great potential for antibiotic-containing wastewater treatment. Herein, we developed an iron phosphide/carbon composite and verified its capability and superiority towards a model antibiotic pollutant (sulfathiazole, STZ) degradation through PMS activation. Benefiting from the chelating ability of phytic acid (PA) with metal ions and its abundance on phosphorous element, a PA-Fe3+ complex was firstly formed and then served as sole precursor for iron phosphide formation by anoxic pyrolysis. Well crystalized FeP particle were found loading on the simultaneously formed thin layer carbon structure. Catalytic activity evaluation showed that FeP/carbon composite could remove over 99% of STZ (20 mg L−1) in 20 min adsorption and 30 min catalysis process under the reaction conditions of catalyst dosage 0.2 g L−1, PMS loading 0.15 g L−1. A pseudo-first-order reaction rate constant of 0.2193 min−1 was obtained, which was among the highest compared with reported studies. Further investigations indicated that the developed FeP/carbon composite worked well in a wide solution pH range of 3–9. Reaction mechanism study showed that reactive species of SO4−• and 1O2 generated from PMS activation played major roles for STZ degradation. Based on liquid chromatography-mass spectroscopy (LC-MS) analysis, a few STZ degradation intermediate products were identified, which facilitated the proposal of STZ degradation pathways. The possible ecological risk of STZ and related degradation intermediates were also considered by toxicity assessment using the Ecological Structure Activity Relationships (ECOSAR) Class Program. The obtained acute and chronic toxicity values implied the relatively low ecological risk of FeP/carbon-PMS reaction system for STZ treatment.

Reliable and Representative Estimation of Extrapolation Model Application in Deriving Water Quality Criteria for Antibiotics.

Deriving water quality benchmarks based on the species sensitivity distribution (SSD) is crucial for assessing the ecological risks of antibiotics. The application of extrapolation methods such as interspecies correlation estimation (ICE) and acute-to-chronic ratios (ACRs) can effectively supplement insufficient toxicity data for these emerging contaminants. Acute-to-chronic ratios can predict chronic toxicity from acute toxicity, and ICE can extrapolate an acute toxicity value from one species to another species. The present study explored the impact of two extrapolation methods on the reliability of SSDs by analyzing different scenarios. The results show that, compared with the normal and Weibull distributions, the logistic model was the best-fitting model. For most antibiotics, SSDs derived by extrapolation have high reliability, with 82.9% of R2 values being higher than 0.9, and combining ICE and ACR methods can bring a maximum increase of 10% in R2 . Based on the results of Monte Carlo simulation, the statistical uncertainty brought by ICE in SSD is 10-40 times larger than that brought by ACR, and combining the two methods could reduce uncertainty. In addition, the sensitivity test showed that whether the toxicity data came from extrapolation or actual measurement, the lower the value of toxicity endpoints was, the greater the bias caused by the corresponding species in every scenario. Combining the two aforementioned extrapolation methods could effectively increase the stability of SSD, with their bias nearly equal to 1. Environ Toxicol Chem 2023;42:191-204. © 2022 SETAC.

From Molecular Descriptors to Intrinsic Fish Toxicity of Chemicals: An Alternative Approach to Chemical Prioritization.

The European and U.S. chemical agencies have listed approximately 800k chemicals about which knowledge of potential risks to human health and the environment is lacking. Filling these data gaps experimentally is impossible, so in silico approaches and prediction are essential. Many existing models are however limited by assumptions (e.g., linearity and continuity) and small training sets. In this study, we present a supervised direct classification model that connects molecular descriptors to toxicity. Categories can be driven by either data (using k-means clustering) or defined by regulation. This was tested via 907 experimentally defined 96 h LC50 values for acute fish toxicity. Our classification model explained ≈90% of the variance in our data for the training set and ≈80% for the test set. This strategy gave a 5-fold decrease in the frequency of incorrect categorization compared to a quantitative structure-activity relationship (QSAR) regression model. Our model was subsequently employed to predict the toxicity categories of ≈32k chemicals. A comparison between the model-based applicability domain (AD) and the training set AD was performed, suggesting that the training set-based AD is a more adequate way to avoid extrapolation when using such models. The better performance of our direct classification model compared to that of QSAR methods makes this approach a viable tool for assessing the hazards and risks of chemicals.

Occurrence and Source Identification of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans and Polychlorinated Biphenyls in Surface Sediments from Liangshui River in Beijing, China

Polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls were measured in the surface sediments of Liangshui River, the second largest drainage river in Beijing, China. The sum concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls ranged from 3.5 to 3019 (mean value: 184) pg g-1 dry weight and from 319 to 5949 (mean value: 1958) pg g-1 dry weight, and the corresponding World Health Organization toxic equivalent quantity values were 0.0011-5.1 pg TEQ g-1 dry weight and 0.0074-1.4 pg TEQ g-1 dry weight, respectively. The spatial distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls showed increasing trends from urban area and development area to suburb. Principal component analysis revealed that polychlorinated dibenzo-p-dioxins and dibenzofurans contamination in the sediments may originate from pentachlorophenol and sodium pentachlorophenate and municipal solid waste incineration. Regarding polychlorinated biphenyls, the steel industry, combustion processes and usage of some commercial polychlorinated biphenyl products were identified as the major sources. The emission from a former steel plant could be the main contributor to polychlorinated biphenyls in urban areas. The mean value of the total toxic equivalent quantities in the sediment samples exceeded the Canadian interim sediment quality guidelines. Long-term wastewater irrigation increases the load of sediment-bound pollutants in agricultural soil and may pose potential ecological risks to crops and human health.

Toxicity test of LC-50 (Lethal Concentration) surfactant LAS (Linear Alkylbenzene Sulfonate) against white snapper (Lates calcarifer) fingerlings on a laboratory scale

LAS (Linear Alkylbenzene Sulfonate) surfactants are the main cleaning agents from the anionic group found in detergents that are widely used in Indonesia. LAS decomposes in surface water for 1-2 days, in sediments it decomposes for 1-3 days, in marine and estuarine systems it decomposes for 5-10 days. LAS is generally degraded by as much as 90% within 3 months, with a time ranging from 5-30 days (World Health Organization, 1996). LAS surfactants can cause damage to the gill epithelium and blockage of branchiola channels in fish. This study aims to determine the toxic effect of LAS surfactant on the survival of white snapper (Lates calcarifer) fry and to determine the toxicity value of LC50 (Lethal Concentration) of LAS surfactant to white snapper (Lates calcarifer) fry on a laboratory scale. This research was carried out on September 21 – October 04, 2021 at the Marine Science Laboratory, Faculty of Agriculture, Malikussaleh University using laboratory experimental methods with 5 treatments, namely: control treatment A (0 ppm), B (0.83 ppm), C (1.58 ppm). ), D (2.16 ppm), and E (2.91 ppm). The results of this study cause barramundi to experience irregular movements, mouth opening and operculum tend to be fast and irregular, scales are pale and peeling, and cause death, LAS surfactants affect water quality such as pH and dissolved oxygen, but have no effect on salinity and temperature. The 24-hour LC50 value is 1.95 ppm, the 48-hour LC50 value is 1.86 ppm, the 72-hour LC50 value is 1.70 ppm, and the 96-hour LC50 value is 1.58 ppm.Key words : LAS surfactant; LC50; toxicity; white snapper

Occurrence Characteristics and Ecological Risk Assessment of Organophosphorus Compounds in a Wastewater Treatment Plant and Upstream Enterprises

Organophosphorus compounds have toxic effects on organisms and the ecosystem. Therefore, it is vital to monitor and control the effluent organophosphorus levels of wastewater treatment plants (WWTPs). This study analyzed the composition and concentration of organophosphorus compounds from the upstream enterprises of a WWTP and conducted ecological risk and toxicity assessments using ECOSAR (ecological structure activity relationship model), T.E.S.T (Toxicity Estimation Software Tool), and risk quotient (RQ) methods. A total of 14 organic phosphorus pollutants were detected in the effluent of the upstream enterprises and WWTP. The concentration of influent total organic phosphorus from the WWTP was 39.5 mg/L, and the effluent total organic phosphorus was merely 0.301 mg/L, indicating that good phosphorus removal was achieved in the WWTP. According to the acute and chronic toxicity analysis, the ECOSAR ecotoxicity assessment showed that 11 kinds of organophosphorus compounds were hazardous to fish, daphnia, and algae in different degrees. Among them, triphenyl phosphine (TPP) had a 96 hr LC50 of 1.00 mg/L for fish and is a substance with high acute toxicity. T.E.S.T evaluates the acute toxicity of each organophosphorus component and the bioconcentration factor (BCF). The evaluation results showed that the LC50 of TPP and octicizer were 0.39 and 0.098 mg/L, respectively, and the concentrations of these two organophosphorus compounds from the effluent of an environmental protection enterprise were as high as 30.4 mg/L and 0.735 mg/L, which exceeded the acute toxicity values and has led to serious hazards to aquatic organisms. The BCF values of each organophosphorus component in the upstream enterprises and the effluent of the WWTP were less than 2000, implying that there was no bioaccumulation effect on aquatic organisms. The developmental toxicity assessment demonstrated that there were nine types of organophosphorus compounds belonging to developmental toxicants, that the presence of developmental toxicants was found in the effluent of each upstream enterprise, and that triethyl phosphate (TEP) was the most common organophosphorus compound. Comparing the RQ of the effluent from various enterprises, it was found that the effluent from the environmental protection enterprise presented the highest degree of environmental hazard, mainly due to the higher toxicity of TEP and octicizer.

Understanding hazardous concentrations of microplastics in fresh water using non-traditional toxicity data

Microplastic pollution has become a major environmental problem, indicating the need to implement quantitative governance standards in combination with reducing or banning single-use plastic. Previous studies have predicted no-effect concentrations for limited microplastic-based toxicity data but have not considered environmentally relevant sizes, shapes, or polymers. To provide high quantity and quality data for microplastics of different sizes, shapes, or polymer compositions, non-traditional and traditional toxicity data may need to be considered in combination. In this study, we reviewed toxicity data for microplastics in freshwaters from 2018 to 2022 and analyzed the toxicity data using traditional and non-traditional methods. Based on 166 chronic traditional toxicity data points, the hazard concentration (HC) values calculated from non-traditional toxicity endpoints or all toxicity endpoints were lower than those calculated from traditional toxicity endpoints. Based on 398 chronic traditional plus non-traditional toxicity data points, the HC values calculated from traditional plus non-traditional values were higher than those calculated from traditional toxicity values. With these results, we developed a new framework for deriving microplastic-specific hazardous concentrations, one that especially considers non-traditional toxicity endpoints and values for microplastics. Overall, this study offers a basis for future management strategies and associated frameworks for mitigating microplastic toxicity.

Poison frog dietary preference depends on prey type and alkaloid load.

The ability to acquire chemical defenses through the diet has evolved across several major taxa. Chemically defended organisms may need to balance chemical defense acquisition and nutritional quality of prey items. However, these dietary preferences and potential trade-offs are rarely considered in the framework of diet-derived defenses. Poison frogs (Family Dendrobatidae) acquire defensive alkaloids from their arthropod diet of ants and mites, although their dietary preferences have never been investigated. We conducted prey preference assays with the Dyeing Poison frog (Dendrobates tinctorius) to test the hypothesis that alkaloid load and prey traits influence frog dietary preferences. We tested size preferences (big versus small) within each of four prey groups (ants, beetles, flies, and fly larvae) and found that frogs preferred interacting with smaller prey items of the fly and beetle groups. Frog taxonomic prey preferences were also tested as we experimentally increased their chemical defense load by feeding frogs decahydroquinoline, an alkaloid compound similar to those naturally found in their diet. Contrary to our expectations, overall preferences did not change during alkaloid consumption, as frogs across groups preferred fly larvae over other prey. Finally, we assessed the protein and lipid content of prey items and found that small ants have the highest lipid content while large fly larvae have the highest protein content. Our results suggest that consideration of toxicity and prey nutritional value are important factors in understanding the evolution of acquired chemical defenses and niche partitioning.

Toxicity test of LC-50 (Lethal Concentration) surfactant LAS (Linear Alkylbenzene Sulfonate) against white snapper (Lates calcarifer) fingerlings on a laboratory scale

LAS (Linear Alkylbenzene Sulfonate) surfactants are the main cleaning agents from the anionic group found in detergents that are widely used in Indonesia. LAS decomposes in surface water for 1-2 days, in sediments it decomposes for 1-3 days, in marine and estuarine systems it decomposes for 5-10 days. LAS is generally degraded by as much as 90% within 3 months, with a time ranging from 5-30 days (World Health Organization, 1996). LAS surfactants can cause damage to the gill epithelium and blockage of branchiola channels in fish. This study aims to determine the toxic effect of LAS surfactant on the survival of white snapper (Lates calcarifer) fry and to determine the toxicity value of LC50 (Lethal Concentration) of LAS surfactant to white snapper (Lates calcarifer) fry on a laboratory scale. This research was carried out on September 21 – October 04, 2021 at the Marine Science Laboratory, Faculty of Agriculture, Malikussaleh University using laboratory experimental methods with 5 treatments, namely: control treatment A (0 ppm), B (0.83 ppm), C (1.58 ppm). ), D (2.16 ppm), and E (2.91 ppm). The results of this study cause barramundi to experience irregular movements, mouth opening and operculum tend to be fast and irregular, scales are pale and peeling, and cause death, LAS surfactants affect water quality such as pH and dissolved oxygen, but have no effect on salinity and temperature. The 24-hour LC50 value is 1.95 ppm, the 48-hour LC50 value is 1.86 ppm, the 72-hour LC50 value is 1.70 ppm, and the 96-hour LC50 value is 1.58 ppm.Key words: LAS surfactant; LC50; toxicity; white snapper

Characterizing surface water concentrations of hundreds of organic chemicals in United States for environmental risk prioritization.

Thousands of chemicals are observed in freshwater, typically at trace levels. Measurements are collected for different purposes, so sample characteristics vary. Due to inconsistent data availability for exposure and hazard, it is complex to prioritize which chemicals may pose risks. We evaluated the influence of data curation and statistical practices aggregating surface water measurements of organic chemicals into exposure distributions intended for prioritizing based on nation-scale potential risk. The Water Quality Portal includes millions of observations describing over 1700 chemicals in 93% of hydrologic subbasins across the United States. After filtering to maintain quality and applicability while including all possible samples, we compared concentrations across sample types. We evaluated statistical methods to estimate per-chemical distributions for chosen samples. Overlaps between resulting exposure ranges and distributions representing no-effect concentrations for multiple freshwater species were used to rank estimated chemical risks for further assessment. When we apply explicit data quality and statistical assumptions, we find that there are 186 organic chemicals for which we can make screening-level estimates of surface water chemical concentration. Of the original 1700 observed chemicals, this number decreased primarily due to a predominance of censored values (that is, observations indicating concentrations too low to be measured). We further identify 423 chemicals where all measurements were censored but, through consideration of detection limits, risk might still be prioritized based on the detection limits themselves. In the final set of 1.5 million samples, the median environmental concentration of one chemical (acetic acid) exceeded the 5th percentile of no-effect concentrations for the most delicate freshwater species (the highest priority risk condition identified here), and a further 29 chemicals were identified for possible further evaluation based on a small margin between occurrence and toxicity values. This method shows the broad range of chemical concentrations seen for organic chemicals across the country and identifies methods of determining their central tendency, allowing for researchers to characterize higher-than-normal or lower-than-normal surface water conditions as well as providing an overall indication of the presence of organic chemicals in the United States. The highest chemical concentrations did not always indicate the highest-risk conditions. Even when accounting for the high level of uncertainty in these data due to differences in data collection and reporting across the set, some chemicals may still be categorized as higher environmental risk than others using this method, providing value to chemical safety decision makers and researchers by suggesting avenues for more focused investigation.

In Silico Molecular Docking and ADMET Analysis for Drug Development of Phytoestrogens Compound with Its Evaluation of Neurodegenerative Diseases

Neurodegenerative disease is one of the problems faced by postmenopausal women due to estrogen deficiency. Phytoestrogen compounds can be used as an alternative treatment for diseases caused by estrogen deficiency by binding to their receptors through the estrogen receptor (ER) dependent pathway. With in silico studies, this study aims to predict how phytoestrogen compounds will stop neurons from dying by using the dependent ER pathway. Genistein, daidzein, glycitein, formononetin, biochanin A, equol, pinoresinol, 4-methoxypinoresinol, eudesmin, α-amyrin, and β-amyrin compounds were prepared with ChemDraw Ultra 12.0. Then their pharmacokinetic and pharmacodynamic properties were examined using SwissADME. Geometry optimization of the compound was performed using Avogadro 1.0.1, and molecular docking of the compound to the ERα (1A52) and ERβ (5TOA) receptors was performed using AutoDock vina (PyRx 0.8). The interaction visualization stage was carried out with Biovia Discover Studio 2021, while the toxicity values of the compounds were analyzed using pkCSM and ProTox II. The results showed that the equol compound met the pharmacokinetic, pharmacodynamic, toxicity criteria, and had similarities with the native ligand 17β-estradiol. Equol compound inhibits neurodegeneration via an ER-dependent pathway by binding to ERα (1A52) and ERβ (5TOA) receptors.