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Invasive alien species (IAS) exert a negative impact on native ecosystems and on various human activities. Limnoperna fortunei (Dunker 1857), a sessile mytilid introduced from Asia in the Río de la Plata, demonstrates a high dispersal capacity, growing over other organisms and artificial structures. Understanding its behavior is crucial for developing appropriate control and mitigating its detrimental effects. This study investigated the population dynamics of this mollusk in response to urban effluents in a large river. Water and population parameters of L. fortunei were measured both upstream and downstream of a small town from July to December 2020. Downstream areas exhibited increased temperature and decreased transparency compared to upstream locations, while pH, conductivity, and dissolved oxygen remained relatively constant. However, downstream, the L. fortunei population comprised fewer and smaller individuals, displaying high width-to-length ratios. Most measured water parameters exhibited significant differences between sampling months. The abundance of L. fortunei remained relatively stable over time due to its nearly continuous reproduction in Uruguay. Nonetheless, shell elongation (15.3-22.8 mm) coincided with an increase in dry weight (0.009-0.038 g) from winter to spring. Allometric relationships, primarily following a power-law model, varied between months, ranging from H = 0.39L1.04 to H = 1.36L0.57. This study contributes to the comprehension of the population dynamics and life history of L. fortunei, thereby aiding in the conservation of invaded aquatic systems. Moreover, it provides valuable insights into the effects of urban effluents on this species, contributing to our understanding of its potential role as a bioindicator.

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In this study, the multi-marker approach was used for the first time with a highly urbanized lake located in the city of Fortaleza, Brazil, to provide a comprehensive view of temporal trends in sources of pollutants and evaluate the relation between the influence of anthropogenic activities and socioeconomic development. Total concentrations of the markers analyzed ranged from 21.0 to 103.8 ng g-1, 450.2 to 2390.2 ng g-1, and 233.8 to 9827.3 ng g-1 for ∑PAHs, ∑n-alk, and ∑sterols, respectively. Concentrations and patterns of PAH, AH, and sterol ratio distribution changed over time and may be associated with different episodes in the history of the city of Fortaleza. The marker ratio distribution in the sediment core revealed an overlap of natural and anthropogenic sources, with degraded oil, biogenic inputs, pyrogenic processes, and fecal contamination from humans and animals in the past changing to petroleum fossil inputs and high contamination from sewage in the present day. The distribution of markers and the chronological history of Fortaleza revealed two distinct periods related to human activities during the development of the city. In the first period (prior to the 1950s), the main human activities were animal breeding and the use of biomass for domestic activities, public and cargo transportation, and commercial activities, especially food production. In the second period (after the 1950s), expansion of the city occurred due to the so-called Brazilian economic miracle and the main human activities were industrialization and urbanization processes, involving deforestation, paving, sewage discharge, and petroleum combustion.

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In an urban scenario, one of the air pollutants most harmful to human health and environmental is the particulate matter (PM). Considering that urban green areas can contribute to mitigating the effects of PM, this work compares the concentration of PM2.5 in two closer locations in Rio de Janeiro, in order to verify how vegetation cover can actually improve air quality. One is the entrance to the Rebouças Tunnel (RT) and the other is the Rio de Janeiro Botanical Garden (RJBG). For this purpose, PM2.5 samples were taken from September 2017 to March 2018 using a Large Volume Sampler (LVS). The results reveal that RT has a higher concentration of PM2.5 in almost all samples. The RJBG obtains concentrations around 33% less than the other area, suggesting that the presence of urban green areas like the RJBG can reduce PM2.5 levels when compared to places with less vegetation cover, providing better air quality.

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The Metropolitan Region of Rio de Janeiro is the second largest urban and industrial region in Brazil. While the south and south-east areas are affected by vehicular emissions, the districts and cities located in the northern area are subjected to industrial emissions and have the poorest air quality of the region. In this study, BTEX concentrations were determined in the District of Irajá, a residential area located in the north of the city of Rio de Janeiro, approximately 25 km from the industrial zone, as well as in the District of Jardim Primavera, in the city of Duque de Caxias. The mean values for total BTEX concentrations were 38.4 ± 11.7 and 44.6 ± 29.3 µg m-3, in Irajá and Jardim Primavera, respectively, which are higher than those previously reported for other areas. The benzene/toluene rates, (approximately 0.5 for both sampling sites), were also higher than typical values that were determined for diesel and gasoline emissions through dynamometer experiments.

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Tropical regions experience naturally high levels of UV radiation, but urban pollution can reduce these levels substantially. We analyzed 20 years of measurements of the UV index (UVI) at several ground-level locations in the Mexico City Metropolitan Area and compared these data with the UVI values derived from the satellite observations of ozone and clouds (but not local pollution). The ground-based measurements were systematically lower than the satellite-based estimates by ca. 40% in 2000 and 25% in 2019. Calculations with a radiative transfer model using observed concentrations of air pollutants explained well the difference between satellite and ground-based UVI and showed specific contributions from aerosols, O3, NO2, and SO2 in decreasing order of importance. Such large changes in UV radiation between 2000 and 2019 have important implications ranging from human health (skin cancer and cataract induction) to air pollution control (photochemical smog formation).

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Animals have a long history of assessing ecosystem responses to environmental disturbances, and amphibians stand out for presenting themselves as good animal model and bioindicators of environmental quality. The main purpose of the present work was to investigate the cellular effects of contamination of waters of the Marrecas River, located in the southwest of the state of Paraná, Brazil. Therefore, the objective of the present study was to investigate and monitor the cytotoxic and mutagenic effect, with bullfrog tadpoles, and to discuss these effects with land use along this hydrographic basin. Mutagenic effects were determined by micronucleus assay, and cytotoxicity by other nuclear changes, such as segmented cells, binucleated cells, cells with buds and reniform cells. Water samples were obtained at nine sites along the Marrecas River, covering areas with rural and urban hydrological contribution. For each site, four samples were collected, along the years 2017 and 2018, encompassing the four seasons (summer, autumn, winter, and spring). The results showed mutagenic and cytotoxic effect in four sampling sites, and only cytotoxic effect in other four sites. These effects may be due, possibly, to the use of different agrochemicals across the hydrographic basin region, which have predominant hydrological contributions from crops. Data of this study indicate the presence of cytotoxic and mutagenic contaminants in the waters of the Marrecas River, which can generate environmental problems on the river fauna/flora, and can also affect the local population health.

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Ice and snow in the Central Andes contain significant amounts of light-absorbing particles such as black carbon. The consequent accelerated melting of the cryosphere is not only a threat from a climate perspective but also for water resources and snow-dependent species and activities, worsened by the mega-drought affecting the region since the last decade. Given its proximity to the Andes, emissions from the Metropolitan Area of Santiago, Chile, are believed to be among the main contributors to deposition on glaciers. However, no evidence backs such an assertion, especially given the usually subsident and stable conditions in wintertime, when the snowpack is at its maximum extent. Based on high-resolution chemistry-transport modeling with WRF-CHIMERE, the present work shows that, for the month of July 2015, up to 40% of black carbon dry deposition on snow or ice covered areas in the Central Andes downwind from the Metropolitan area can be attributed to emissions from Santiago. Through the analysis of aerosol tracers we determine (i) that the areas of the Metropolitan Area where emissions matter most when it comes to export towards glaciers are located in Eastern Santiago near the foothills of the Andes, (ii) the crucial role of the network of Andean valleys that channels pollutants up to remote locations near glaciers, following gentle slopes. A direct corollary is that severe urban pollution, and deposition of impurities on the Andes, are anti-correlated phenomena. Finally, a two-variable meteorological index is developed that accounts for the dynamics of aerosol export towards the Andes, based on the zonal wind speed over the urban area, and the vertical diffusion coefficient in the valleys close to ice and snow covered terrain. Numerous large urban areas are found along the Andes so that the processes studied here can shed light on similar investigations for other glaciers-dependent Andean regions.

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Impacts on urban water resources are invariably caused by the development of urban centers and the occupation of the watershed. The release of untreated effluents and urban runoff are sources of metals in adjacent water bodies. It is therefore important to conduct studies on the occurrence of these trace elements in the environment and the risks posed to human health. The aim of the present study was to determine Cd, Pb, Cu, and Zn concentrations in water bodies located in the Bacanga and Cachorros watersheds and correlate the occurrence of these elements with physicochemical variables of the water (temperature, pH, dissolved oxygen, and electrical conductivity). The variables were determined at the collection site with the aid of a multiparameter kit. Heavy metal concentrations were determined using anodic stripping voltammetry. The results revealed that the streams were not contaminated with the metals analyzed. The only exception was copper in the Limoeiro and Murtura streams, both of which are located in the industrial complex.

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Low-cost air quality sensors are widely used to improve temporal and spatial resolution of air quality data. In Lima, Peru, only a limited number of reference air quality monitors have been installed, which has led to a lack of data for establishing environmental and health policies. Low-cost technology is promising for developing countries because it is small and inexpensive to operate and maintain. However, considerable work remains to be done to improve data quality. In this study, a low-cost sensor was installed with a reference monitor station as the first stage for the calibration process, and a multiple regression model was developed based on reference measurements as an outcome variable using sensor data, temperature, and relative humidity as the predictive parameters. The results show that this particular technology exhibits a promising performance in measuring PM2.5 and PM10 (particulate matter with diameter aerodynamic less than 2.5 µm and 10 µm, respectively); however, the correlation for PM2.5 appears to be better. Temperature and relative humidity data from the sensor were only partially analyzed due to the evident low correlation with the reference meteorological data. The objective of this study is to begin analyzing the performance of low-cost sensors that have already been introduced to the Peruvian market and selecting those that perform better to provide for informed decision-making.

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ANTECEDENTES Y OBJETIVO Contaminación del aire es un importante factor de riesgo y un crucial factor que contribuye a la carga de enfermedad a nivel global, además de tener una incidencia directa sobre la calidad de vida de la población. En este contexto, la División de Planificación Sanitaria solicita una síntesis de evidencia con el objetivo de conocer el efecto de estrategias regulatorias para la reducción de contaminantes del aire, y de esta manera informar la toma de decisiones respecto a los efectos que tendría la implementación de distintas estrategias para abordar la contaminación del aire. METODOLOGÍA Se formuló una estrategia de búsqueda la cual se utilizó en las bases de datos HealthSystemsEvidence, SocialSystemsEvidence, Epistemonikos, PubMed, Campbell Collaboration y la Collaboration for Environmental Evidence, con el objetivo de identificar revisiones sistemáticas que abordaran la pregunta formulada. Luego, se estructuró la pregunta de acuerdo con las intervenciones encontradas para preparar un resumen de la evidencia disponible. Se utiliza la metodología de certeza de evidencia GRADE Se incluyeron todos los tipos de acciones, ya sean políticas, intervenciones y estrategias dirigidas al control, regulación o disminución de contaminantes ambientales. Se excluyeron intervenciones relacionadas a la dieta de las personas y acciones enfocadas en la contaminación intradomiciliaria. RESULTADOS Se recuperaron 4 Revisiones sistemáticas, de las cuales se obtuvieron los siguientes resultados: -Las estrategias para regular la contaminación del aire podrían reducir las tasas de mortalidad en la población -Es incierto si las políticas regulatorias mejoran el desarrollo neurológico de los niños, porque la certeza en la evidencia es muy baja. -Dentro de las políticas para reducir la contaminación del aire, Chile cuenta con medidas que regulan las emisiones de gases. De esta forma, se podría explorar estrategias para mejorar el cumplimiento de este tipo de iniciativas, en caso de que esto se considere como un elemento relevante para la política.

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