Determination of The Ecological Water Quality in The Orienco Stream Using Benthic Macroinvertebrates in The Northern Ecuadorian Amazon

In recent years, pollution of watercourses in nearby protected ecosystems has increased due to urbanization. Standard physiochemical methods and probes are one way to monitor watercourses for quality. However, they often do not provide the full ecological status of the body of water. In this work, we set out to assess the ecological water quality of an urban stream by using benthic macroinvertebrates as bioindicators. We conducted the work on the Orienco stream in Lago Agrio in the province of Sucumbíos in the Northern Ecuadorian Amazon (NEA). The stream has become a sink of raw domestic sanitary wastewater from rural and urban areas. A total of 4511 macroinvertebrates from 10 families were identified across 17 sampling points. We compared our results from the biotic indices derived from the macroinvertebrates to standard water-quality parameters (temperature, conductivity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total suspended solids, ammonia–nitrogen, and pH) simultaneously sampled in the stream. The standard parameter results indicated that the water-quality levels of the stream met the Ecuadorian water-quality criteria most of the time. However, the results from the biotic indices classified the stream water as poor or very poor water quality. The results from the Biological Monitoring Working Party, Average Score per Taxon, and Family Biotic Indices had overall scores of heavily polluted waters of 45, 4.5, and 8.74, respectively. Furthermore, these results were consistent with reduced richness and evenness, and overall lower Shannon diversity and relatively higher Simpson Dominance indices of 0.71 and 2.56, respectively. We conclude that the macroinvertebrates were better indicators of the ecological water quality of the Orienco stream than the water-quality parameters from standard methods and probes alone. Our findings highlight the need for more integrated ecological assessments, which can provide critical information to the management and conservation strategies of urban watercourses in the NEA region. Integr Environ Assess Manag 2022;00:1–11. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

Stability of citrate-capped silver nanoparticles in exposure media and their effects on the development of embryonic zebrafish (Danio rerio)

The stability of citrate-capped silver nanoparticles (AgNPs) and the embryonic developmental toxicity were evaluated in the fish test water. Serious aggregation of AgNPs was observed in undiluted fish water (DM-100) in which high concentration of ionic salts exist. However, AgNPs were found to be stable for 7 days in DM-10, prepared by diluting the original fish water (DM-100) with deionized water to 10%. The normal physiology of zebrafish embryos were evaluated in DM-10 to see if DM-10 can be used as a control vehicle for the embryonic fish toxicity test. As results, DM-10 without AgNPs did not induce any significant adverse effects on embryonic development of zebrafish determined by mortality, hatching, malformations and heart rate. When embryonic toxicity of AgNPs was tested in both DM-10 and in DM-100, AgNPs showed higher toxicity in DM-10 than in DM-100. This means that the big-sized aggregates of AgNPs were low toxic compared to the nano-sized AgNPs. AgNPs induced delayed hatching, decreased heart rate, pericardial edema, and embryo death. Accumulation of AgNPs in the embryo bodies was also observed. Based on this study, citrate-capped AgNPs are not aggregated in DM-10 and it can be used as a control vehicle in the toxicity test of fish embryonic development.Keywords: Nanoparticle Exposure Media, Nanoparticle Stability, Embryonic Zebrafish Toxicity, Silver Nanoparticle

Impact of Microsparticle Concentration Levels upon Toxicity of Phenol to Artemia

Plastic pollution constitutes a threat to marine wildlife because of the deleterious impacts ranging from entanglement to ingestion of plastic debris. However, knowledge regarding the impacts of fragmented plastics into micron sizes and their interaction with other toxicants in the marine environment is still limited. In the present study the impact of polystyrene microspheres, 3 µm in diameter, upon toxicity of phenol to the brine shrimp Artemia was investigated in acute toxicity tests. The brine shrimp are employed as a model organism in marine toxicity tests. Phenol is a hydrophobic compound used as an intermediate resin discharged to the environment. Adult brine shrimps reared in the laboratory were exposed to phenol at nominal concentrations ranging from 40 to 200 mgL-1 to quantify the toxicity of phenol. Polystyrene microspheres at nominal concentrations of 100, 200 and 300 mgL-1 were then loaded to the phenol solutions to examine their impact upon toxicity of phenol to the brine shrimp. Results suggested that toxicity of phenol, as expressed by LC50 values, was lowered by the addition of higher concentrations of microspheres to test solutions for 48-h and 72-h exposure times. The data suggest that sorption of phenol to polystyrene beads is supported by other plastic congener profiles, protecting the brine shrimp against toxic levels of phenol. Moreover, the body burden of beads was increased with the increase of bead concentration, reveling that more beads in the organism can interact with the chemical

APPLICATION OF THE TENAX TECHNIQUE TO ASSESS BIOACCESSIBILITY OF SEDIMENT-ASSOCIATED POLYCHLORINATED BIPHENYLS

Sediments can act as both reservoir and source of legacy organic contaminants such as polychlorinated biphenyls (PCBs). Due to their chemical stability and ubiquity, these contaminants remain as model class of compounds in the field of sediment contamination. Whole sediment and organism concentrations have been often used as exposure metrics for ecological risk assessments. However, whole sediment concentrations often overestimate the potential for exposure to contaminants; while organism concentrations based on bioassay provide a better estimate of exposure, bioassays can also be labor intense, time consuming and expensive. Alternatively, accessiblity-based techniques such as Tenax extractions have been gaining ground, in the last few decades, as a rapid, reliable, and cost-effective approach to estimate exposure to organic contaminants from sediments. Tenax extractions measure the bioaccessible fraction of the contaminant that desorbes from sediment. Despite the simplicity, accuracy and robustness of the Tenax technique to estimate bioaccessibility of organic contaminants, there are still some remaining questions regarding the methodological standardization, and the applicability of the technique in sediments containing diverse carbonaceous sorbents associated adsorption/desorption of the contaminant. Therefore, the chapters of this dissertation were designed to address these questions. To this end, PCBs were chosen as a model compound class to represent a wide range of physicochemical properties of persistent organic contaminants, and because these compounds remain a worldwide legacy contamination problem. The dissertation goals were to: determine the best operational conditions for Tenax technique (Chapter 2); monitor the changes in bioaccessibility of field-collected sediments with different holding time conditions (Chapter 3); examine the effects of the type and quantity of organic carbon on bioaccessibility (Chapter 4); and evaluate the applicability of the Tenax technique to assess remediation success in contaminated marine sediments (Chapter 5). To address the methodological standardization of the Tenax technique, the operational parameters of solvent extract volume, Tenax sorption rate from water, and Tenax:OC (Tenax:Organic Carbon) ratios were investigated in Chapter 2. The highest efficiency of extraction of sorbed PCBs from Tenax resulted from using a 10 mL per each solvent wash during Tenax extraction procedure. For the Tenax sorption, it was found that 0.01 g of Tenax cleared PCB in 40 mL of water in 30 min, thus it would clear the water 48 times in 24 h. When this is extrapolated to the 0.5 of Tenax, typical amount used, it was found that the amount should clear the typical volume of water used on Tenax extraction about 2400 times. This represents unequivocal evidence that the Tenax resin would remove PCBs dissolved in the liquid phase (e.g., overlying or interstitial water) present in the sediment sample and be limited only by compound desorption and not by the Tenax sorption capacity. The results examining the impact of the relationship between the amount of Tenax required and the amount of organic carbon in the sediment extraction indicated that a minimum of 5:1 Tenax:OC ratio be used to conduct Tenax extractions. This will reduce (eliminate) the possibility of re-adsorption by the native OC in the sediment in competition with the Tenax. After ascertaining the best operational conditions for Tenax extractions, two additional methodological uncertainties, the effect of storage time after collection and the preservation method associated with the handling of collected sediment samples were investigated in Chapter 3. The effect of holding time and the preservation method on PCB concentrations from field-collected sediments was examined for a period of 196 d. All samples were held at 4 ºC in the dark and several holding times were chosen. The parameters to track the changes in PCB concentration in two sediments used three exposure metrics: exhaustive solvent extraction, tissue concentrations and Tenax extractions (Chapter 3). The results showed that the total exhaustive concentrations representing the whole sediment concentrations did not significantly change (ANOVA, p\u3e 0.05) in either sediment over the course of 196 d. Similar results were also found for the total Tenax concentrations that represented the bioaccessible sediment concentrations, and for the total organism tissue concentrations representing exposure. The likely equilibrium of PCB in the sediment, their chemical stability of PCB and slow degradation can be underlined as the main factors leading to these results. The long time that legacy contaminants such as PCBs have been in contact with contaminated sites (e.g., Superfund sites) might have contributed to an equilibrium to be reached between the sediment particles and PCB molecules. The significance of this chapter is that sediments collected from PCB-contaminated sites can be stored longer than the 14 d as recommended by current standard protocols without disturbing the measures of bioavailability. The role of organic carbon composition within sediment on contaminant sorption was also investigated to ascertain the effects of type and quantity of OC from different origins on the bioaccessibility of PCBs in contaminated sediments (Chapter 4). Changes in PCB bioaccessibility in sediments amended at either 3 or 6% by dry weight with black carbon (BC), humic acid (HA) or sawdust (SD), showed that the lowest and highest PCB bioaccessibilities were observed in the BC and SD amendments, respectively. Specifically, the total amount of PCBs desorbed ranges from 3 to 27% for BC amendments, 12 to 55% for HA amendments and 16 to 80% for SD amendments. The results showed the influence of OC quantity on bioaccessibility having a much slower desorption of PCBs in 6% amendments compared to 3% amendments, and this finding was most evident in HA and BC amendments. The results also showed that the Tenax technique can be applied to tract the variation in type of carbon and quantity of OC in contaminated sediment to estimate exposure. Finally, the applicability of the Tenax technique as tool to assess the remediation success of PCB-contaminated marine sediments upon AC amendment at either 4.3 or 0.026% AC by dw was examined in Chapter 5. The results showed that bioaccessibility of PCBs was greatly reduced in sediment amended at the higher AC dose (4.3%); while, reduction was also observed even in the sediment amended at 0.026% AC. Furthermore, the results revealed that Tenax concentrations reflected the PCB reduction among AC amended sediments in the same direction as the PCB reduction in the organism bioaccumulation. Overall, this dissertation provides further evidence that the Tenax technique is a rapid, reliable, and cost-effective tool for estimating exposure to recalcitrant organic contaminants such as PCBs from contaminated sites. The applicability of the technique to estimate bioaccessible compound from both freshwater and marine aquatic sediments underline the robustness of the technique to widen its use among risk ecological assessor and researchers

The Impact of Surface Ligands and Synthesis Method on the Toxicity of Glutathione-Coated Gold Nanoparticles

Gold nanoparticles (AuNPs) are increasingly used in biomedical applications, hence understanding the processes that affect their biocompatibility and stability are of significant interest. In this study, we assessed the stability of peptide-capped AuNPs and used the embryonic zebrafish (Danio rerio) as a vertebrate system to investigate the impact of synthesis method and purity on their biocompatibility. Using glutathione (GSH) as a stabilizer, Au-GSH nanoparticles with identical core sizes were terminally modified with Tryptophan (Trp), Histidine (His) or Methionine (Met) amino acids and purified by either dialysis or ultracentrifugation. Au-GSH-(Trp)2 purified by dialysis elicited significant morbidity and mortality at 200 μg/mL, Au-GSH-(His)2 induced morbidity and mortality after purification by either method at 20 and 200 μg/mL, and Au-GSH-(Met)2 caused only sublethal responses at 200 μg/mL. Overall, toxicity was significantly reduced and ligand structure was improved by implementing ultracentrifugation purifications at several stages during the multi-step synthesis and surface modification of Au-GSH nanoparticles. When carefully synthesized at high purity, peptide-functionalized AuNPs showed high biocompatibility in biological systems

Cultivo de huayaipe, seríola rivoliana, en piscinas provistas de geomembranas

El estudio preliminar para cultivar huayaipe, Seriola rivoliana, en piscinas provistas de geomembranas se llevo a cabo haciendo un análisis técnico-financiero de la factibilidad de realizar la evaluación de adaptar este tipo de cultivo a la infraestructura camaronera subutilizada o no operante en el sector acuícola del país. Así, con la recopilación de experiencias realizadas, el presente estudio tiene la intención de servir de guía para quienes de una forma u otra deseen incursionar en cultivos alternativos haciendo uso, por una parte, de las instalaciones acuícolas disponibles y de los criterios técnicos alcanzados en el campo de la diversificación. La evaluación de la fase técnica se analizó en el contexto de poder cultivar ejemplares de huayaipe tanto en su fase larvaria como en su fase de engorde, bajo los criterios técnicos que demandan las especies de estas características biológicas. Tomando como punto de partida el realizar una adecuación, de las áreas estrictamente necesarias, de una infraestructura ya existente (laboratorio de larvas de camarón y piscinas de producción de camarón). Mientras que, la evaluación económica permitió identificar los costos de producción para cada fase, asimismo, consideró la aplicación de indicadores económicos universales para poner en consideración la rentabilidad de poder desarrollar este tipo de cultivos. Finalmente luego de haber realizado el estudio preliminar de cultivo de huayaipe en piscinas provistas de geomembranas en base a criterios técnicos y económicos se pone a disposición las proyecciones realizadas para cada una de las fases de cultivo, dejando así en esta tesis una herramienta de que hace el papel de guía para las personas que quieran realizar diversificar sus cultivos a través de peces marinos como es el huayaipe

Cultivo de huayaipe, seríola rivoliana, en piscinas provistas de geomembranas

El estudio preliminar para cultivar huayaipe, Seriola rivoliana, en piscinas provistas de geomembranas se llevo a cabo haciendo un análisis técnico-financiero de la factibilidad de realizar la evaluación de adaptar este tipo de cultivo a la infraestructura camaronera subutilizada o no operante en el sector acuícola del país. Así, con la recopilación de experiencias realizadas, el presente estudio tiene la intención de servir de guía para quienes de una forma u otra deseen incursionar en cultivos alternativos haciendo uso, por una parte, de las instalaciones acuícolas disponibles y de los criterios técnicos alcanzados en el campo de la diversificación. La evaluación de la fase técnica se analizó en el contexto de poder cultivar ejemplares de huayaipe tanto en su fase larvaria como en su fase de engorde, bajo los criterios técnicos que demandan las especies de estas características biológicas. Tomando como punto de partida el realizar una adecuación, de las áreas estrictamente necesarias, de una infraestructura ya existente (laboratorio de larvas de camarón y piscinas de producción de camarón). Mientras que, la evaluación económica permitió identificar los costos de producción para cada fase, asimismo, consideró la aplicación de indicadores económicos universales para poner en consideración la rentabilidad de poder desarrollar este tipo de cultivos. Finalmente luego de haber realizado el estudio preliminar de cultivo de huayaipe en piscinas provistas de geomembranas en base a criterios técnicos y económicos se pone a disposición las proyecciones realizadas para cada una de las fases de cultivo, dejando así en esta tesis una herramienta de que hace el papel de guía para las personas que quieran realizar diversificar sus cultivos a través de peces marinos como es el huayaipe

DriveAware: Generating Actionable Data through Vehicle-Based Citizen Science

Submission to the May 2022 LUC Computer Science Research Symposium Submission type: lightning talk/demo hybri

Estructura y estimación del carbono acumulado en el estrato arbóreo de un bosque siempreverde de tierras bajas: Caso Parque Ecológico Recreacional Lago Agrio, Sucumbíos,

The present study focused on determining forest structure and carbon aboveground storage of a forest from the Northern Ecuadorian Amazon. The study site was located at the “Parque Ecologico y Recreacional Lago Agrio (PERLA)” in Lago Agrio, Sucumbíos in Ecuador. We established 10 study transects at 500 m2 to measure trees from the site with dbh (mean diameter at breast height) ≥ 10 cm (D1, 30m). On the trees surveyed, we measured the importance index value (IVI), alpha diversity index, and tree aboveground biomass using allometric models reported for tropical forests. We reported 672 trees ha-1 taxonomically ranked within 25 families, 35 genera and 42 species. The results showed that species with the higher IVI index values included Guarea kunthiana, Inga spp, Nectandra guadaripo, Pourouma minor, Chrysophyllum argenteum; while, for the upper arboreal composition the species included Pourouma minor Vochysia ferruginea y Dussia lehmannii. Furthermore, the alpha diversity index for the arboreal composition was 1392 bits, we thought that this was due to the lack of uniformity in the species distribution within the site. The results also showed a strong correlation between tree biomass and DBH values (p < 0.001; R2 ≥ 0.92). Finally, our results showed that the forest at the PERLA site had 271.5 Mg ha-1 aboveground biomass and 135.8 Mg ha-1 carbon storage.El presente estudio se enfocó en determinar la estructura y estimación del carbono acumulado en el estrato arbóreo del bosque del Parque Ecológico y Recreacional Lago Agrio (PERLA) situado en la Provincia de Sucumbíos Cantón Lago Agrio Parroquia Nueva Loja. Para lo cual se establecieron10 transectos de 500m2 se tomó datos de todos los individuos >= 10 cm de D1,30m. Se determinó características estructurales del bosque como índice de valor de importancia (IVI), índice de diversidad de alfa, biomasa almacenada mediante modelos alométricos para bosques tropicales. Se registraron un aproximado de 672 individuos ha-1 agrupados en 25 familias, 35 géneros y 42 especies. Las especies con mayor IVI fueron: Guarea kunthiana, Inga spp, Nectandra guadaripo, Pourouma minor, Chrysophyllum argenteum, el estrato superior está representado por Pourouma minor Vochysia ferruginea y Dussia lehmannii. La diversidad florística de estrato arbóreo es de 1392 bits, debido principalmente a la baja uniformidad en la distribución de los individuos en cada especie. La biomasa aérea arbórea se correlacionó fuertemente con el DAP. Se pudo determinar que en la actualidad el bosque acumula 271.5 Mg ha-1 de biomasa y 135.8 Mg ha-1 de carbono, mostrando una relación de dependencia (p = 0.92) entre DAP y biomasa

Estudio exploratorío de la presencia de actividad antibacteriana en la sangre de la concha prieta anadara similis

El presente trabajo describe la presencia mayoritaria de células circulantes en la sangre de la concha prieta y la presencia de actividad antibacteriana en estas células. Las observaciones de microscopía óptica muestran a estas células mayoritarias como un grupo homogéneo con una morfología característica. Las células descritas en este estudio presentan un núcleo bien definido y abundantes estructuras citoplasmáticas similares a gránulos. El presente trabajo también establece la existencia de una cierta actividad antibacteriana de los lisados de las células circulantes de la concha prieta contra 3 cepas bacterianas identificadas como Bacillus sp.-2, Vibrio harveyi y Vibrio anguillarum. Además, bajo las condiciones de experimentación de este trabajo, se descarta que el origen de estas actividades antibacterianas se encuentre localizado en cualquier célula distinta de las células circulantes de la concha prieta. El presente estudio, es a nuestro conocimiento, la primera descripción de la presencia de actividad antibacteriana en el molusco Anadara similis