Search

Este estudio analizó la distribución espacial y temporal de 13 plaguicidas en sedimento y tejido de lobina (Micropterus spp.), por técnicas de análisis espacial y multivariantes en la presa “Vicente Guerrero” (Tamaulipas, México). Los compuestos fueron detectados por HPLC-MS/MS siguiendo el procedimiento de extracción QuEChERS. La concentración media de plaguicidas varió en sedimento de 0.37 a 8.33 µg/kg y en lobina de 0.05 a 2.88 µg/kg. La variación espacial fue significativa en los cinco sitios muestreados tanto en sedimento como en pescado. La mayor concentración y diversidad de plaguicidas se dio en la zona de confluencia (centro y zona este) en el embalse y declinó hacia el vertedero. La variación temporal en sedimento fue significativa (p < 0.05) en todo el periodo muestreado, mientras que en lobina solo en diciembre y mayo. Los plaguicidas más frecuentes en los dos tipos de muestras fueron amitraz, etión, paratión, piriproxifen y propargita, este último con la mayor variación y presente solo en el centro de la presa. Los resultados sugieren bioacumulación de al menos cinco plaguicidas desde el sedimento hacia el pescado. El paratión ha sido señalado como extremadamente peligroso para la salud humana; junto con etión y propargita son altamente tóxicos para la vida acuática, por lo que se sugiere realizar monitoreo frecuente de la presa, a fin de detectar la presencia de plaguicidas de alto riesgo y conservar la sanidad del ecosistema.

This article discusses ethical frameworks for planning and implementing composite research in the United States. Composites, defined here as archaeological materials with multiple genetic sources, include materials such as sediment, coprolites, birch pitch, and dental calculus. Although composites are increasingly used in genetic research, the ethical considerations of their use in ancient DNA studies have not been widely discussed. Here, we consider how composites' compositions, contexts, and potential to act as proxies can affect research plans and offer an overview of the primary ethical concerns of ancient DNA research. It is our view that ethical principles established for analyses of Ancestral remains and related materials can be used to inform research plans when working with composite evidence. This work also provides a guide to archaeologists unfamiliar with genetics analyses in planning research when using composite evidence from the United States with a focus on collaboration, having a clear research plan, and using lab methods that provide the desired data with minimal destruction. Following the principles discussed in this article and others allows for engaging in composite research while creating and maintaining positive relationships with stakeholders. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding species distribution patterns and what determines them is critical for effective conservation planning and management. In the case of shorebirds migrating along the East Asian‐Australasian Flyway (EAAF), the loss of stopover habitat in the Yellow Sea region is thought to be the primary reason for the precipitous population declines. However, the rates of decline vary considerably among species, and it remains unclear how such differences could arise within a group of closely related species using apparently similar habitats at the same locales. We mapped the spatial distributions of foraging shorebirds, as well as biotic (benthic invertebrates consumed by migrating shorebirds) and abiotic (sediment characteristics) environmental factors, at a key stopover site in eastern China. Five of the six sediment characteristics showed significant spatial variation with respect to distance along the shoreline or distance from the seawall in the same tidal flat. The biomasses of four of the six most abundant benthic invertebrates were concentrated in the upper or middle zones of the tidal flat. The distribution patterns of all three focal shorebird species on the tidal flat were best explained jointly by this heterogeneity of sediment characteristics and invertebrate prey. These results suggest that the loss of tidal flats along the Yellow Sea, which is typically concentrated at the upper and middle zones, may not only reduce the overall amount of staging habitat, but also disproportionately affect the most resource‐rich portions for the birds. Effective conservation of shorebird staging areas along the EAAF and likely elsewhere must consider the subtle habitat heterogeneity that characterizes these tidal flats, prioritizing the protection of those portions richest in food resources, most frequently used by focal bird species, and most vulnerable to anthropogenic threats. Article impact statement: Heterogeneity of tidal flats with respect to biotic and abiotic factors must be considered in shorebird conservation planning. [ABSTRACT FROM AUTHOR]

Identifying, quantifying and spatialising factors that condition water erosion processes, such as erosivity, can help to understand the process of sediment input to watercourses and, in this specific case, to hydroelectric plant reservoirs. The aim of this study was to estimate and spatialise rainfall and erosivity indices in the Area of Direct Influence (AID) of the Batalha reservoir (GO/MG). Using the database provided by the National Water Agency's (ANA) HIDROWEB portal, the equation proposed Silva et al. (1997) was adopted, and to measure the accuracy of the erosivity estimation models, the Fournier index (1958) was adopted for rainfall in the region, for a historical series from 1991 to 2021. To do this, the estimates took into account monthly and annual rainfall and their spatial variability for the south-eastern regions of Goiás and north-western Minas Gerais. By means of a descriptive analysis and spatialisation of the Erosivity Index (EI), in the study of annual variability, there was a tendency for it to increase in an approximately north-south direction, towards the south and centre-south. Similarly, in the study of monthly variability, there was an increase in the EI also in an approximately north-south direction, towards the south and centre-south, in the months with the highest rainfall. It was also observed that the months with the highest rainfall, corresponding to the spring and summer seasons, had the highest Erosivity Indices, classified as high and very high, except for October. For the drier months, corresponding to autumn and winter, these indices were classified as low and very low. Overall, the average annual erosivity was classified as high. [ABSTRACT FROM AUTHOR]

Benthic cyanobacteria research in high mountain reservoirs remains limited, mainly due to their complexity and knowledge gaps that persist in relation to their ecology in tropical regions. This study aimed to explore the composition, diversity, and toxic potential of cyanobacterial in the upper sediment of two Colombian reservoirs. Our investigation involved multiple methodologies, such as germination experiments, that allowed us to assess the presence and viability of cyanobacteria in upper sediment samples, while the competitive ELISA assay allowed for the quantification of toxins within the cultures. The molecular analysis of Operational Taxonomic Units (OTUs) from subsamples of sediment cultures focused on evaluating cyanobacterial diversity and richness among prokaryotic phyla, and the Phylogenetic analysis of culturable cyanobacteria. Chlorophyll-a measurements confirmed the presence of viable populations in sediment cultures, while microscopic identification demonstrated the growth capacity of cyanobacteria from the orders Nostocales, Chroococcales, Oscillatoriales, and Synechococcales under controlled laboratory conditions. Despite low microcystin levels in culture, the prior detection of mcy genes in direct sediment samples suggests a possible toxic potential of cyanobacterial inhabiting the upper sediments. Community analysis, based on the OTUs abundance, revealed a notably diverse microbial community in both reservoir sediments, with a higher relative abundance of cyanobacteria compared to other prokaryotic phyla. These findings support the hypothesis that surface sediments play a fundamental role as a repository for cyanobacteria that may pose inherent risks to ecosystem health. In conclusion, this research underscores the necessity of further studies to achieve a holistic comprehension of benthic cyanobacteria dynamics in high-mountain tropical reservoirs. [ABSTRACT FROM AUTHOR]

Copyright of Water & Landscape (WAL) / Agua & Territorio (AYT) is the property of Editorial de la Universidad de Jaen and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A poluição de sistemas aquáticos com contaminantes emergentes é uma crescente preocupação. Dentre estes, os desreguladores endócrinos (DE) são substâncias que podem alterar o sistema endócrino de seres vivos até em baixas concentrações. Suas características físico-químicas indicam afinidade com matéria orgânica, sendo relevante o estudo de sedimentos. A atividade estrogênica pode ser avaliada pelo ensaio in vitro YES, porém matrizes ambientais complexas podem apresentar citotoxicidade e interferir no resultado do ensaio. Este estudo objetivou avaliar métodos de preparo de amostras de sedimento utilizando extração em fase sólida para remoção de compostos citotóxicos no ensaio in vitro YES. O uso isolado de EDTA para remoção de metais não foi eficiente para reduzir a citotoxicidade, enquanto a remoção foi completa com o cartucho SAX. Conclui-se que o uso combinado de cartuchos foi a técnica mais viável para a avaliação da atividade estrogênica de amostras de sedimento com ensaio YES.

Dos materiales locales fácilmente accesibles, caolín y sedimentos de un embalse, se evaluaron para comparar sus eficiencias como adsorbentes para arsénico. La muestra de caolín estaba compuesta sobre todo de caolinita y cuarzo, mientras que los sedimentos constaban de illita, montmorillonita y cuarzo. Componentes en menores proporciones fueron minerales de hierro, calcio y magnesio. Se realizaron experimentos de adsorción por lotes para medir la influencia del pH, tiempo de contacto, concentración inicial de arsénico y tratamientos químicos, los cuales se llevaron a cabo utilizando reactivo piraña y ácido trimésico para estudiar sus efectos en la capacidad de adsorción. El reactivo piraña parece ser una buena alternativa para mejorar la capacidad de absorción del caolín, mientras que la adsorción inicial usando ácido trimésico tiene solo un ligero efecto positivo en los sedimentos del embalse. Los sedimentos sin tratar mostraron mayores capacidades de adsorción que el caolín natural o tratado. Una gran parte de la adsorción parece deberse a las partículas más finas de los sedimentos, compuestas principalmente de minerales de hierro, en tanto que la materia orgánica casi no contribuye a la adsorción. Se emplearon los modelos de Freundlich y Dubinin-Kaganer-Radushkevich para evaluar la capacidad de adsorción de arsénico de los sedimentos intactos y tratados con ácido trimésico. La máxima capacidad de adsorción observada experimentalmente fue de 137 mg/kg para los sedimentos intactos después de cinco horas de reacción, que es ligeramente inferior a la medida para los tratados con ácido trimésico.

Introduction. The aquatic ecosystem as the final recipient of waste produced by anthropogenic and natural processes is a growing pollution problem on our planet and currently the presence of heavy metals, they present is an alarming index. This research is important because the Ite district uses river water as an elemental liquid for its daily activities and consumption. The Locumba River sub-basin is located within the Ite district and is characterized by mining and agricultural activities. Objective. Determine the quality of the river sediments through the concentrations of heavy metals (As, B, Cd, Cr, Cu, Fe, Mn and Pb) in the upper area of the Locumba river. Materials and methods. In the months of January and March, sampling was carried out in an altitudinal range between 350 and 800 meters above sea level, in the dry and rainy season. The guide for sediment sampling (LSASDPROC- 200-R4), USEPA quality standards, was used. The analyzes were performed by ICPOES Plasma Spectroscopy. Results. The concentration levels show us that heavy metals are present as; Arsenic exceeded standards of 58 ppm on average, Boron with 8.2 ppm, Copper with 372 ppm and Lead with 121 ppm. Conclusions. The sediment quality of the Locumba River due to the presence of heavy metals is not adequate and brings with it environmental risks, affecting the biota and ecosystems. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Poluentes orgânicos foram identificados em diferentes matrizes ambientais: água, sedimento e organismos de nível trófico secundário. A identificação ocorreu em nove sites ao longo de três zonas, durante os meses de dezembro de 2017 e junho de 2018 em dois períodos amostrais, respectivamente estiagem e chuvoso. A área de estudo foi o Estuário do Rio Mamanguape, localizado no bioma Floresta Atlântica no estado da Paraíba-Brasil, a qual faz parte de uma Área de Preservação Permanente. Foram identificados 62 poluentes nas matrizes ambientais durante os dois períodos amostrais. As substâncias identificadas são utilizadas para diversos fins, como: Agentes de produtos industriais 53%, Fármacos 24%, Agrotóxicos 16% e Produtos de cuidado pessoal 6%. Durante os dois períodos houve diferença significativa da ocorrência dos poluentes orgânicos, com α< 0,05 para a água e o sedimento, sendo o período de estiagem o com maior diversidade de poluentes. No entanto, o mesmo comportamento não foi encontrado para os organismos de nível trófico secundário.

Al 2020 en Costa Rica únicamente, existen tres barreras dinámicas instaladas, dos de las cuales se encuentran en la Quebrada Burío. El cambio climático es un factor determinante ante el incremento de las intensidades de lluvia. Se espera un incremento del 20% para el año 2100 por lo que este dato se toma en cuenta para realizar todos los cálculos hidrológicos del caso de estudio. Al mismo tiempo, la implementación del modelo de Iber 2.5.1 es totalmente necesaria para la comprensión del comportamiento hidrodinámico de la quebrada y asimismo del comportamiento de los sedimentos en suspensión de ésta. Datos como hidrogramas, elevaciones obtenidas por medio de ortofotos de vuelos de aeronaves no tripuladas y concentración de sedimentos son los pilares para generar un modelo para este caso. La velocidad, altura del agua y comportamiento vectorial son los resultados obtenidos del modelo hidrodinámico generado por Iber 2.5.1. Así como el comportamiento de los sedimentos.

Land‐use change is considered one of the greatest human threats to marine ecosystems globally. Given limited resources for conservation, we adapted and scaled up a spatially explicit, linked land–sea decision support tool using open access global geospatial data sets and software to inform the prioritization of future forest management interventions that can have the greatest benefit on marine conservation in Vanuatu. We leveraged and compared outputs from two global marine habitat maps to prioritize land areas for forest conservation and restoration that can maximize sediment retention, water quality, and healthy coastal/marine ecosystems. By combining the outputs obtained from both marine habitat maps, we incorporated elements unique to each and provided higher confidence in our prioritization results. Regardless of marine habitat data source, prioritized areas were mostly located in watersheds on the windward side of the large high islands, exposed to higher tropical rainfall, upstream from large sections of coral reef and seagrass habitats, and thus vulnerable to human‐driven land use change. Forest protection and restoration in these areas will serve to maintain clean water and healthy, productive habitats through sediment retention, supporting the wellbeing of neighboring communities. The nationwide application of this linked land–sea tool can help managers prioritize watershed‐based management actions based on quantitative synergies and trade‐offs across terrestrial and marine ecosystems in data‐poor regions. The framework developed here will guide the implementation of ridge‐to‐reef management across the Pacific region and beyond. [ABSTRACT FROM AUTHOR]

As lagoas costeiras ocupam 13% da costa do planeta. No Brasil, ocorrem ao longo de toda a costa, com destaque para os Estados do Rio de Janeiro e Rio Grande do Sul. Em função de sua localização geográfica, as lagoas costeiras estão sujeitas a diversos impactos antrópicos. Ações multidisciplinares mitigadoras desses impactos são imprescindíveis para a mudança das condições atuais das lagoas costeiras do litoral brasileiro. Para isso, é necessário um maior conhecimento dos impactos causados e suas consequências para o funcionamento desses ecossistemas. O aporte de esgoto é um dos impactos ambientais e está diretamente relacionado ao aumento de produtividade do ecossistema. Por sua vez, quanto maior a produtividade aquática em águas lênticas, maior a emissão de metano para a atmosfera. Em um esforço para entender melhor a influência da eutrofização sobre o ciclo do metano, nós analisamos a concentração de metano no sedimento em quatro regiões da Lagoa Imboassica que apresentam diferentes características ambientais. Em cada região, foram coletados testemunhos de sedimento de 10 cm, que foram subdivididos em cinco perfis de 2 cm. Nós analisamos a concentração de metano na água instersticial do sedimento em cada perfil. Nós observamos que as regiões da lagoa influenciadas pelo aporte de esgoto apresentaram as maiores concentrações de metano no sedimento. Concluímos que o tratamento de esgoto é fundamental para a mitigação da eutrofização e, consequentemente, da produção de metano no ecossistema.

The article analyzes the sediment composition in a trout farm in Colombia. Differences were found in the parameters of available phosphorus, organic matter, organic carbon, and C: N ratio among the sectors of the farm. The study shows the impact of fish production on sediment composition. The use of sediments in agriculture and the importance of controlling sediment recirculation in wastewater treatment plants are also discussed. The article provides relevant information for aquaculture and sustainable agriculture. [Extracted from the article]

La Ciénaga Grande de Santa Marta (CGSM) es un importante ecosistema para la biodiversidad del planeta. Las actividades antrópicas generan residuos e incrementan los niveles de contaminantes, afectando la calidad del agua, la salud de la población y del ambiente. Con el objetivo de determinar el contenido de metales pesados y calidad del agua de la CGSM, se analizaron muestras de agua, en nueve sitios para las variables temperatura, sólidos disueltos totales (STD), pH, conductividad eléctrica (CE), salinidad, NO3-, NH4+, PO43-, Ca+2, Mg+2, Na+, SO42-, CO32-, HCO3-, Ni, Cd, Cr, Pb, Coliformes totales y termotolerantes. La concentración de Pb, Cd, Cr y Ni fue más baja que el valor de referencia para agua marina. La máxima concentración de Pb y Cd, se presentó en el sitio 6, con 17,76 y 0,48ppb, respectivamente. La salinidad correlacionó con Ni (r = 0,98), pH con contenidos de Ni y Cr (r = 0,99 y 0,43, respectivamente), OD se asoció con concentración de Cd y Pb (r = 0,72 y 0,67, respectivamente), STD se encuentra asociado con NI y Cr (r = 0,97 y 0,56, respectivamente), DBO con concentración de Cd (r = 0,79). La concentración de metales pesados encontrados constituye una alerta para el ecosistema, debido a la posible biodisponibilidad ante algunas condiciones ambientales y, a la vez, son reflejo de afectación de variables de calidad del agua del estuario, con transporte de materia orgánica, sedimentos y aportes de nutrientes. Los valores elevados de CT y CF afectan la salud del ecosistema.

Los residuos minero-metalúrgicos que se encuentran expuestos a la intemperie son una fuente de contaminación que pueden afectar la salud de la población, deteriorar la calidad del hábitat y reducir la biodiversidad. Las situaciones donde estos residuos constituyen un riesgo potencial y permanente se denominan pasivos ambientales mineros. Las estrategias de remediación son más efectivas entre mejor se conozca la magnitud de la contaminación, su potencial de dispersión y su toxicidad potencial. En este artículo se mencionan las ventajas de usar sedimentos como medio de muestreo y algunas de las metodologías para su análisis que han sido utilizadas con éxito. Se concluye con las recomendaciones de: a) generar mapas donde se puedan visualizar fácilmente las áreas más contaminadas; b) complementar los mapas con información local sobre la movilidad de los elementos potencialmente tóxicos, su asociación con otros metales, así como las características del medio ambiente que podrían afectar su toxicidad, y; c) considerar aspectos políticos y sociales asociados con el pasivo ambiental minero. Abstract The mining-metallurgical wastes that lay exposed to the weather represent a source of contamination that can affect public health, deteriorate the quality of the habitat and reduce biodiversity. Cases where these wastes constitute a permanent and potential risk of contamination are known as mining environmental liability situations. Remediation strategies are more effective the better known the degree of contamination, its potential for dispersion and its potential toxicity. This article lists the advantages of using sediments as sampling medium and some methodologies of analysis that have been reported as successful. The author concludes with these recommendations, to (a) generate concentration maps where areas of highest contamination are visually identifiable, (b) provide complementary local information about mobility of potentially toxic elements, their association with other metals, and environmental characteristics that may influence their toxicity, and (c) consider political and social aspects associated with mining environmental liability . Keywords: contamination, metal, mining environmental liability, sediment, toxicity.

El aumento en el uso de combustibles fósiles y el desarrollo industrial, ha llevado al aumento de la concentración de hidrocarburos aromáticos policíclicos (HAP) en los recursos naturales incluyendo el aire, el agua y el suelo, esto ha derivado en el incremento de enfermedades respiratorias, dérmicas, cancerígenas, mutagénicas y teratogénicas en la población. Esta revisión, tiene como objetivo presentar las fuentes de emisión, transporte, destino, los principales congéneres de HAP, sus propiedades fisicoquímicas, el muestreo pasivo, las técnicas de extracción y la aplicación de metodologías analíticas en agua y sedimentos como la cromatografía de gases acoplada a espectrometría de masas, que permiten la evaluación de estas sustancias y garantizar la calidad de los recursos hídricos. En Colombia se han presentado dificultades en la implementación de estas técnicas de extracción e identificación de HAP debido a su elevado costo y al desconocimiento de los riesgos ambientales y a la salud humana por parte de las autoridades.

La erosión del suelo es un problema ampliamente reconocido. Sin embargo, resulta muy difícil evaluar de manera fiable y precisa la magnitud y la tasa del proceso a nivel de lote y de cuenca. El modelo Water Erosion Prediction Project (WEPP) es una herramienta de simulación continua, capaz de cuantificar los procesos de remoción de sedimentación y escurrimiento a nivel de lote y cuenca. El objetivo de este estudio fue comparar el escurrimiento medido en una cuenca con el simulado mediante el modelo WEPP y estimar la producción de sedimentos para diferentes rotaciones. El estudio se realizó en una cuenca agrícola de 27 ha con rotación Trigo/Soja 2ª-Maíz-Soja, y se la comparó con Soja continua, Trigo/Soja 2ª, Maíz continuo, Maíz-Soja-Trigo/ Soja 2ª y Cultivo de Cobertura/Maíz-Soja-Trigo/Soja 2ª. Los resultados fueron analizados mediante el coeficiente de eficiencia de Nash & Sutcliffe (E), análisis de regresión (R²) y análisis de varianza. Al analizar el conjunto de datos para los años 2012 y 2013, con alta variabilidad en el total anual precipitado (1352.6 y 851.6 mm, respectivamente), se observó una buena relación entre los valores de escurrimiento medidos y los simulados por WEPP (R²= 0.79), mientras que la eficiencia del modelo fue superior a la media de los datos medidos (E=0.66). Esto demuestra que, en el conjunto de los datos, WEPP fue capaz de absorber la variabilidad climática de forma eficiente. La producción de sedimentos estimada mediante WEPP para la rotación actual fue de 4.8 Mg ha-1 año-1, valor considerado adecuado teniendo en cuenta que la cuenca no presentó signos visibles de erosión hídrica. En las 5 rotaciones simuladas, el monocultivo de soja presentó las mayores pérdidas de agua por escurrimiento y de suelo por erosión. Esto podría deberse a que, al ser elevado los volúmenes escurridos, el agua se encauce provocando además de erosión laminar, erosión en surcos, transportando así mayor cantidad de sedimentos. La rotación que incorporó cultivo de cobertura redujo el escurrimiento y la producción de sedimentos.

This paper is a thought experiment to attune to the geo-physical and geo-political materialities of sediment, a terra-aqueous substance produced when the earth's continental surfaces intra-act with the atmosphere and are chemically transformed by it. The paper is framed by questions of how to engage more closely with the dynamics of earth systems and of how social and political agency emerges alongside earth forces. Sediment is important to such questions because it is the mechanism by which the earth recycles itself and is thick with the climatological and geological histories that have conditioned the possibility of life on the planet. While acknowledging the import of Deleuze and Guattari's metaphysics to such questions, the paper takes a material approach to them. It is based on field work in Bangladesh, but also traverses a range of scientific, historical and theoretical literature. It is arranged in four sections that loosely correspond to the sedimentary cycle. It follows sediment from chemical processes on rock surfaces in the Himalayas, to its lively travels in monsoonal rivers across flood plains to its eventual deposition and subterranean diagenesis. In each section, the paper discusses the material processes at work, their socio-political enmeshments and the theoretical implications of these intra-actions. The paper concludes that sediment serves as a reminder not only of close entanglements of geo-physical and geo-political becomings, but also of the profound indifference of earth systems to human affairs, and asks what this might mean for the re-imagination of politics. [ABSTRACT FROM AUTHOR]

Building on a small, yet growing body of scholarship focused on the political ecology of race and critical race studies of science and technology, this article follows the ways sediment, science, and race intersect on the grounds of environmental restoration in coastal Louisiana. Mobilizing ethnographic field work and historical research conducted with African-American communities and coastal scientists, I empirically expand upon geographer Kathryn Yusoff's (2018) notion of the "geosocial registers" of the Anthropocene through an examination of the entwined histories of coastal engineering and racial inequality that situate contemporary debates about large scale coastal restoration projects along Louisiana's disappearing coastline. In dialogue with critical work on the relationship between racism, science, and the constitution of the Anthropocene, I argue that coastal restoration is a geophysical and social process upon which racial inequality is forged and contested. The article concludes by considering how environmental restoration can participate in creating alternative forms of social and environmental repair by aligning the goals of coastal science with those of racial justice for communities of color living in changing coastal landscapes. [ABSTRACT FROM AUTHOR]

Copyright of Summa, Animali da Compagnia is the property of Point Veterinaire Italie s.r.l. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the increase in fish production in fish farming systems, mainly tilapia, the use of the hormone 17α- methyltestosterone (MT) as an inducer of the masculinization of fry has grown together. The probability of contamination of natural resources also tends to increase, and there is no Brazilian law that regulates the content of this hormone in waters. The study of the interaction of the hormone with the typical soil of the producing regions is essential to understand the factors that influence its adsorption. This work used two samples of Eutropherric Red Oxisols and the conditions of the interaction of the hormone in static (resting), and dynamic (agitation) processes were evaluated, using isothermal models. The results showed that the higher organic matter content of the soil and the higher salinity of the aqueous medium increases the adsorption of MT in the soil in the static process. For the dynamic process, the Fe content influences the higher adsorption in soil. The pH of the medium does not affect the adsorption in any of the processes. The adsorption has exothermic characteristics, and the adsorption equilibrium is reached in 24 hours, and the Freundlich model for the soil 1 sample and the Temkin model for the soil 2 sample is the most suitable for the adsorption process. According to parameters calculated for the Dubinin isotherm, soil adsorption tends to have chemical interactions between adsorbent-adsorbate. These results show concern for the amount of adsorbed hormone sediment in fish farming tanks and their release to the water body, with the possibility of contamination of natural resources. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The determination of the fall velocity of non-cohesive particles (sand) was measured experimentally by using a technique of filming with a commercial camera. The diameters of the sediment ranged from 0.075 mm to 2 mm, the experimental values were compared with the ones calculated by empirical equations, four equations only consider the diameter to calculate the falling speed, the fifth equation considers diameter and form factor (cfs), and sixth equation considers diameter, form factor, and roundness (P). The results showed that the filming technique allows measuring the falling speed adequately and a sediment diameter range from 0.075 mm to 1.2 mm, the equation that includes the form factors and roundness had one of the best performances. [ABSTRACT FROM AUTHOR]

La degradación de los suelos por erosión hídrica afecta su potencial productivo. En el área agrícola argentina este problema está magnificado por la presencia de paisajes ondulados, lluvias intensas y elevada frecuencia de soja. Para estudiar este fenómeno se han desarrollado modelos como la Ecuación Universal de Pérdida de Suelo (USLE) y Water Erosion Prediction Project (WEPP). Localmente se ha ajustado y validado USLE, aunque es necesario contar con modelos que estimen con mayor precisión la producción de sedimentos y escurrimiento. Los objetivos de este estudio fueron comparar el escurrimiento medido en parcelas con el estimado por WEPP y la producción de sedimentos en parcelas de escorrentía con la estimada con USLE y WEPP. El estudio se realizó sobre parcelas de escorrentía ubicadas en Paraná (Argentina), en cuatro tratamientos: suelo desnudo, maíz, soja a 70 y a 35 cm entre hileras. Para evaluar los modelos se utilizaron el índice Nash-Sutcliffe (E), el R², el intervalo de confianza y el coeficiente de variación. Al comparar los datos promedios anuales de las parcelas con los estimados mediante WEPP, no se encontró diferencia estadísticamente significativa para ningún tratamiento, mientras que los estimados mediante USLE fueron significativamente mayores en los tratamientos de suelo desnudo y maíz continuo. El modelo físico WEPP presentó muy buena eficiencia en la estimación de la producción de sedimentos (E de 0,17 a 0,61), superior a las predicciones del modelo USLE (E de -8,94 a 0,14) para los cuatro tratamientos. En soja continua, WEPP exhibió alta eficiencia de estimación de sedimentos para altos valores de pérdida de suelo, mientras que USLE en valores extremos bajos y altos los sobre y subestimó, respectivamente. La estimación de escurrimiento con el modelo WEPP fue satisfactoria para los cuatro tratamientos (E de 0,27 a 0,44). El uso del modelo físico WEPP permitió representar mejor la realidad de la susceptibilidad a la erosión hídrica de distintos sistemas productivos de la Región pampeana Argentina.

El área de descarga que sirve como cuerpo receptor del efluente industrial que se genera en la planta de alúmina de la empresa Bauxilum, recorre un canal abierto de aproximadamente 650 metros de longitud. Sin embargo, se observan flujos de agua que llevan consigo partículas sólidas y sustancias químicas que se dirigen al canal. Se tomaron 15 muestras de suelo, se seleccionaron 6 de ella. Los análisis granulométricos indican que estos suelos son del tipo SC (suelos arenosos con tamaños de partículas uniformes, con arcillas inorgánicas de baja plasticidad y material gravoso de transición entre roca descompuesta y el suelo). En relación con los análisis químicos se determinó que los suelos son altamente alcalinos, presentando altas concentraciones de sodio (rango entre 5,59% y 8,22%), hierro (rango entre 5,56% y 7,53%) y aluminio (rango entre 10,15% y 18,36%), considerándose ser suelos alcalinos. Estos sedimentos tienen altos niveles de contaminación ambiental, por lo tanto, se deben valorizar para su uso industrial, de esta forma se podría disminuir la potencial afectación de las áreas aledañas a la planta de alúmina.

La espectrometría de Fluorescencia de Rayos-X (FRX) es uno de los métodos más usados para medir datos geoquímicos y aplica técnicas tanto destructivas como no destructivas en la preparación de muestras. Se evaluó la calidad de 12 diferentes elementos usados comúnmente en la investigación de sedimentos calculando la precisión y exactitud de las concentraciones obtenidas en un espectrómetro portátil de FRX por dispersión en energía (Niton FXL 950), a partir de un método de preparación de muestras no destructivo. Los diferentes modos de medida del espectrómetro y la matriz de las muestras no influyeron significativamente en la precisión, aunque ambos influenciaron los valores de la exactitud. La concentración elemental en sedimentos con textura y matriz variables, colectados de la cuenca de Santiaguillo (estado de Durango, México), medida en el FRX por dispersión en energía mostraron correlaciones positivas altas (r≥0.8) con respecto a las concentraciones obtenidas en un espectrómetro convencional FRX para Si, Ti, Al, Fe, Mn, Ca, K, Sr y Zr. Las correlaciones bajas para Mg, P, y Rb (r≤0.7) fueron causadas probablemente por la matriz. Los resultados de elementos con correlaciones altas se corrigieron usando las ecuaciones de regresión lineal entre los datos de ambos espectrómetros. doi: https://doi.org/10.22201/igeof.00167169p.2017.56.3.1819

Diversos estudios muestran el efecto de la temperatura en la bioacumulación de contaminantes en moluscos bivalvos, pero la inuencia de esté factor en la bioacumulación de hidrocarburos (HC) en Crassostrea virginica no se ha reportado. En este trabajo se estudió el efecto de la temperatura sobre la acumulación de HC en C. virginica en condiciones controladas, la tasa de sobrevivencia (TS) y el desarrollo gametogénico. Se aplicaron cuatro tratamientos con diferentes temperaturas y concentración de HC: A (sin HC a 26 ◦C), B (sin HC a 30 ◦C), C (con HC a 26 ◦C) y D (con HC a 30 ◦C) y el control (sin HC a temperatura ambiente). Los resultados mostraron que el control y los tratamientos A y B tuvieron los valores más bajos de bioacumulación de HC con cantidades menores de 30 mg kg−1 . En el tratamiento C se estimaron valores de acumulación de 83 mg kg−1 . Mientras que en el tratamiento D se registraron los niveles más altos de HC con 118 mg kg−1 y la TS más baja (53 %). La TS mayor (93 %) se registró en el control y los tratamientos A y C. A nivel celular no se identicó ninguna patología, pero el desarrollo gonádico fue afectado por la presencia de HC y la temperatura de 30◦C, con escaso crecimiento gonadal, predominando organismos indenidos. Las diferentes temperaturas no inuyeron en la bioacumulación de HC en los organismos, pero se observa efecto negativo en el desarrollo gametogénico y la TS

O objetivo do estudo foi avaliar as condições fisico-químicas e microbiológicas do Córrego do Tanquinho, localizado em área altamente urbanizada e industrializada no município de Ribeirão Preto, SP, Brasil, considerando variações espaciais e temporais. Os parâmetros limnológicos avaliados foram: pH, temperatura, turbidez, condutividade e oxigênio dissolvido (OD), com medições realizadas in situ. Os níveis de metais no sedimento e em água superficial foram analisados por Espectrofotometria de Absorção Atômica. Para a determinação dos Coliformes Totais e Escherichia coli foi empregada a técnica dos Tubos Múltiplos com utilização de substrato cromogênico. Os parâmetros OD, E. coli e a concentração dos metais Cu e Mn na água encontram-se em desacordo com a legislação. Os metais encontrados em maior concentração no sedimento foram Mn, Cr e Zn. A avaliação microbiológica evidenciou o despejo de esgoto doméstico no córrego e as concentrações de metais indicam a possível ocorrência de efluentes industriais, podendo gerar graves problemas de saúde pública. O diagnóstico espacial indicou os locais de amostragem com as piores condições microbiológicas e altas concentrações de metais, enquanto que a influência temporal foi observada no pH, Mn e Cr em água superficial, e Mn, Cr e Pb nos sedimentos. Os resultados mostraram que o Córrego do Tanquinho é um corpo hídrico impactado. Recomenda-se a realização de outros estudos que possam esclarecer melhor a origem das cargas poluidoras, além da conscientização da população e da adoção de medidas que possibilitem a recuperação e proteção desse corpo hídrico.

Copyright of Acta Veterinaria Brasilica is the property of Acta Veterinaria Brasilica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Los habitantes del pueblo de Barra de Potosí en el suroeste de México fueron testigos de la inundación por olas después del sismo de 7.5 Mw del 21 de septiembre de 1985 hasta una distancia de ~ 500 m desde la costa. Se identificaron los sedimentos depositados por la ola de tsunami cerca del estero del Potosí y se compararon la sedimentología, mineralogía y composición química de dichos depósitos con los sedimentos que representan los entornos de pre-tsunami y los depositados en la zona cercana no afectada. Los sedimentos asociados al tsunami se caracterizaron como arenas finas (tamaño medio: 2.13-2.47 Φ), de bien a moderadamente bien ordenados (desviación estándar: 0.4-0.7 Φ). Contienen mayores cantidades tanto de fracciones finas como de gruesas (sesgo de negativo a positivo) y tienen una distribución que va de leptocúrtica a extremadamente leptocúrtica. Las características sedimentológicas de los depósitos de tsunami y los del pre-tsunami son similares. La abundancia y la asociación de los minerales pesados son también comparables en ambos depósitos. Sin embargo, los depósitos de tsunami tienen contenidos más bajos de Br y Fe2O3 y contenidos más altos de SiO2 y TiO2 comparados con los depósitos de pre-tsunami. La comparación con los depósitos ocurridos en la región durante los tsunamis del 14 de marzo de 1979, del 21 de septiembre de 1985 y del 11 de marzo de 2011, no arrojó ninguna firma característica. A excepción de la estratigrafía (i.e. base erosiva), no se observó alguna otra carac-terística geológica que pudiera ser útil para la identificación de paleo-tsunamis en la región. doi: https://doi.org/10.22201/igeof.00167169p.2017.56.1.1747

Abstract Extreme physical conditions usually limit the meiofauna occurrence and distribution in highly hydrodynamic environments such as reflective beaches. Despite sediment grains of the upper layers being constantly resuspended and deposited, the high energy of the swash zone besides depositing coarse sediments allows an ample vertical distribution of meiofaunal organisms. The effect of physical, chemical and sediment variables on the vertical distribution of meiofaunal organims and nematodes was analysed on two reflective exposed beaches. Sampling was conducted at three sampling points on each beach in the swash zone. The sediment collected was divided into four 10-cm strata (0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm). The statistical differences between strata due to factors previously established (i.e. meiofaunal composition, density of most abundant taxa) were tested using a hierarchical PERMANOVA applied under similarity and euclidian distances. An inverse relation among average grain size, content of organic matter and sediment sorting was evident. Coarser sediment characterized the upper layers, while at deeper layers the sediment was very poorly sorted and presented a higher content of organic matter. A similar pattern in the vertical distribution of meiofaunal and nematofaunal composition and density was detected. The lowest densities were associated with the first stratum (0-10 cm), highly affected by hydrodynamics. The vertical distribution of organisms was statistically different only when the interaction among factors was considered. This result suggests that zonation and vertical distribution of meiofaunal organisms are determined by the within-beach variability.

The objective of the current study was to evaluate the concentration of aluminum (Al), iron (Fe) and manganese (Mn) on water and on the sediment of urban rivers (Carahá, Caveiras and Ponte Grande) in Lages, located on the mountain region of Santa Catarina, placed in a coverage area of the Guarani Aquifer. The water and sediment samples were collected between May and October of 2016 in three urban rivers, following an environmental disturbance gradient. For the extraction of the metals present on the sample, it was used the methods 3030 - Standard Methods of Water and Wastewater (2005) for the water samples and ISO 11,466 (1995) for the sediment samples. The quantification of metals was performed through a high-resolution spectrometer with atomic absorption, with a flame automation (acetylene-air or nitrous oxide-air). To evaluate the quantification, it was used a certified material (SRM 2709a - San Joaquin Soil - NIST). On the water samples were found concentrations of Mn above of class III, defined by the Resolution 357/05 of the Environment National Board- Brazil. The Pearson correlation matrix showed a positive correlation between the variables Al/Fe, Fe/Mn e Al/Mn on sediment and Fe/Mn on water. For the sediment, it was found high concentrations of Al, Fe, and Mn in some of the samples. By the results found, it is evinced an increase in the concentration of Al and Fe on the Carahá river sediment, and concentrations of Al, Fe, and Mn on the Ponte Grande river sediment, on the spots located at Lages - SC. [ABSTRACT FROM AUTHOR]

Landfills have been the most used alternative for final municipal solid wastes disposal, however, this system is the responsible of contamination problems associated with the generation of leachates, sediments and toxic gasses emissions. The sediments occur by the organic and inorganic matter precipitation from leachates dumped in retention lagoons, which can present toxic characteristics than affect the environment. The aim of this work was to evaluate the potential toxicity of leachates from a municipal landfill, using the TCLP procedure and acute toxicity assays with Daphnia pulex and Poecilia reticulata as biological indicators. The results showed that the sediment evaluated, did not exceed the stablished levels suggested by the EPA for the TCLP test, nor were they toxic to the organisms used. This results, suggests a potential agricultural use of this material in acid soils, since the nature of leachate sediments are pH alkaline and rich in nutrients and organic matter. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil erosion is a widely recognized problem. However, it is difficult to evaluate, reliably and accurately, the magnitude and rate of soil erosion at a field and watershed level. The Water Erosion Prediction Project (WEPP) is a continuous simulation tool, being capable of quantifying sediment and runoff processes at the field and watershed level. The objective of this study was to compare measured and simulated runoff in a watershed and estimate the sediment yield for different crop rotations using the WEPP model. The study was carried out in a small agricultural watershed of 27 ha, with Wheat/Soybean 2nd-Maize-Soybean crop rotation, near Paraná, Entre Ríos. Estimated soil losses from five crop rotations were compared: Continuous Soybean, Wheat/Soybean 2nd, Continuous Maize, Maize-Soybean-Wheat/Soybean 2nd and Cover crop/Maize-Soybean-Wheat/Soybean 2nd. Nash & Sutcliffe efficiency coefficient of index (E), regression analysis (R2), and analysis of variance were used for data analysis. Measured runoff water and WEPP simulated values were highly related (R2 = 0.79), when analyzing 2012 and 2013 data set; with high variability in the total annual precipitated rain (1352.6 and 851.6 mm, respectively). Model efficiency was higher than the mean of the measured data (E = 0.66), which shows that, in the data set, WEPP was able to take into account climatic variability. Within the actual crop rotation, the agricultural watershed shows no observable signs of water erosion. Sediment yield simulated by WEPP was 4.8 Mg ha-1 yr-1, indicating an acceptable estimation. In the five crop rotations simulated, soybean monoculture presented the highest water runoff and soil loss. This may be because when higher volumes of water runoff are produced, water tends to concentrate on channels causing further interrill and rill erosion carrying higher amounts of sediments. The crop rotation that included cover crops reduced estimated runoff water and sediment production. [ABSTRACT FROM AUTHOR]

Copyright of Anuario do Instituto de Geociencias is the property of Universidade Federal do Rio de Janeiro, Instituto de Geociencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Aim: Here we analyzed some basic ecological attributes (richness and density) of the benthic community in a stretch of a rocky river under the influence of a small dam of a meter in height, forming a small reservoir of run-of-river type. Methods Sediment samples were taken with a Petersen collector at three different periods and in three sites: upstream from the dam (site 1), close to the dam (site 2) and downstream from the dam (site 3). Organisms were separated in large groups and Chironomidae genera. Results The particle size analysis indicated that the sites 1 and 2 are dominated by fine sediments, in contrast to site 3, composed of medium and coarse sediments. A total of 23 taxa of benthic macroinvertebrate groups and 31 genera of Chironomidae were found. Richness and density were different among sampling sites, and for large groups and Chironomidae its attributes increased towards downstream, probably explained by the sediment composition and the originally lotic conditions in site 3, confirmed by all statistical analysis used. In the dam site (2) there was a richness decrease. Non metric multidimensional analysis showed a clear spatial separation of large groups of macroinvertebrates and chironomid genera between sampling sites, indicating that there are typical taxa of each spatial compartment. Canonical correspondence analysis correlated only rubble sediment with the abundance of large groups, and for Chironomidae genera only the granules type was correlationed, with two groups of taxa in the anlysis: one with sites 1 and 2, and other with site 3. Conclusions Even very small dams in rocky rivers as in the present study alter the environmental variables and ecological attributes of benthic macroinvertebrates.

Abstract Numerous factors may affect the pattern of distribution of benthic fauna in a river mouth region and, among the macroinvertebrates, Chironomidae and Oligochaeta are the most abundant groups and most tolerant to environmental changes. Aim The aim of this study was to evaluate the controlling factors of and a possible similarity between Chironomidae and Oligochaeta assemblies at two close sites, the mouth of the Guareí River into the Paranapanema River (São Paulo, Brazil) and its lateral fluvial area. Methods Fauna samples were collected every three months during one year. Water physical and chemical variables and sediment variables were also determined in the same period. Results Both assemblies presented low density variability over time in the lateral area due to sediment characteristics and environmental factors. Taxa Caladomyia, Parachironomus, Pristina sp., Pristina osborni, Bothrioneurum and Opistocysta funiculus were recorded at this site. The Guareí River presented both greater temporal and spatial variations, attributed mainly to a reduction in the water level. Greater organism abundance, especially of Chironomus and Tubificinae, was observed in the river. Conclusions Dissimilarity in temporal and spatial distributions of Chironomidae and Oligochaeta was attributed to peculiar characteristics of the two study sites, a river channel and a lateral area. Reduction in the water level over the year was the main controlling factor of Chironomidae and Oligochaeta richness and density in the river. In the lateral area, the presence and abundance of certain taxa were determined by the nature of the sediment and water physical and chemical variables.

En este artículo se estimaron los desperdicios totales procedentes de la producción de trucha arcoíris, Oncorhynchus mykiss Walbaum (Salmoniformes: Salmonidae), en el lago de Tota, ecosistema de agua dulce ubicado en el departamento de Boyacá (Colombia), y su potencial impacto sobre este. La producción de trucha se desarrolla de manera intensiva en dicho lago desde 2005, utilizando jaulas inmersas. Con datos obtenidos de la Autoridad Nacional de Acuicultura y Pesca (Aunap), la Corporación Autónoma Regional de Boyacá (Corpoboyacá) y la Cámara de Comercio de Sogamoso, se identificaron los piscicultores, su ubicación geográfica en el lago y la producción autorizada de las fincas. Con esta información se calculó la cantidad de desperdicios producidos y las cantidades de nitrógeno y fósforo generados en este proceso. Según los resultados obtenidos, se evidencia la contaminación del lago por la producción intensiva de trucha y se recomienda mejorar o modificar los métodos de producción para minimizar la contaminación del agua.