Influencia de los procesos ambientales predominantes en la cuenca y el embalse Hanabanilla sobre la composición de su sedimento

The Hanabanilla reservoir was built in 1960 in the center-south of Cuba and is used for human supply and power generation. This research was aimed at identifying the important processes affecting sediment composition, through the analysis of particle size, and organic carbon (OC), nutrients, and major trace elements concentrations in sediment samples taken at the outlet point of the reservoir. The documentary review allowed us to identify how the nature and management of the basin and the operation of the reservoir affected sediment quality. The application of principal components analysis (PCA), and the determination of ionic relationships and correlations between the sediment quality variables, allowed for the identification of influential processes on sediment quality. Anthropic activities in the period 1960-2012 produced residues rich in OC, total phosphorus (TP) and total nitrogen (TN) that were stored in reservoir sediments. During the first years of the reservoir (1964-1976) the highest concentrations of sediment TP were recorded and the sediments functioned as a sink. The OC and TN mean concentrations were higher in the last stage of the study (2006-2012). The main influential processes on sediment composition were the operation of the reservoir, the geochemical cycle of P, the mineralization of the substances in the water column, and the weathering of silicates and the contribution of organic matter from the basin. Sediment quality data indicate that OC and TN were of allochthonous origin and TP was of autochthonous origin. Levels of sediment OC and TN also corresponded with an increase in anthropic activities in the basin.El embalse Hanabanilla fue construido en 1960 en el centro-sur de Cuba y sus usos principales son el abastecimiento humano y la generación de energía eléctrica. Esta investigación tuvo como objetivo identificar los procesos fundamentales que afectan la composición del sedimento, mediante el análisis del tamaño de las partículas, y el contenido de carbono orgánico (OC), nutrientes y elementos traza mayoritarios en muestras de sedimento tomadas en la obra de toma del embalse. La revisión documental permitió identificar cómo afectan la naturaleza y el manejo de la cuenca, y la operación del embalse a la calidad del sedimento. El análisis de componentes principales (PCA), las relaciones iónicas, y las correlaciones entre las variables de calidad del sedimento, permitieron identificar los procesos influyentes en la calidad del sedimento. Las actividades antrópicas en el período 1960-2012 produjeron residuos ricos en OC, fósforo total (TP) y nitrógeno total (TN) que se almacenaron en los sedimentos del embalse. Durante los primeros años del embalse (1964-1976), se registraron las más altas concentraciones de TP en el sedimento que actuó como sumidero. Las concentraciones medias de OC y TN fueron más altas en la última etapa del estudio (2006-2012). Los principales procesos que influyeron en la composición del sedimento fueron: la operación del embalse, el ciclo geoquímico del P, la mineralización de las sustancias en la columna de agua, y el lavado de los silicatos, unido a la contribución de la materia orgánica de la cuenca. Los datos indicaron un origen alóctono para el OC y el TN, y autóctono para el TP. Los niveles de OC y TN en el sedimento también se correspondieron con un incremento en la actividad antrópica en la cuenca.Fil: Labaut Betancourt, Yeny. Centro de Estudios Ambientales de Cienfuegos; Cuba. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Betancourt, Carmen R.. Universidad de Cienfuegos Carlos Rafael Rodriguez; CubaFil: Díaz Asencio, Misael. Centro de Estudios Ambientales de Cienfuegos; CubaFil: Beutel, Marc W.. University of California; Estados Unido

Anchored enrichment dataset for true flies (order Diptera) reveals insights into the phylogeny of flower flies (family Syrphidae)

Background: Anchored hybrid enrichment is a form of next-generation sequencing that uses oligonucleotide probes to target conserved regions of the genome flanked by less conserved regions in order to acquire data useful for phylogenetic inference from a broad range of taxa. Once a probe kit is developed, anchored hybrid enrichment is superior to traditional PCR-based Sanger sequencing in terms of both the amount of genomic data that can be recovered and effective cost. Due to their incredibly diverse nature, importance as pollinators, and historical instability with regard to subfamilial and tribal classification, Syrphidae (flower flies or hoverflies) are an ideal candidate for anchored hybrid enrichment-based phylogenetics, especially since recent molecular phylogenies of the syrphids using only a few markers have resulted in highly unresolved topologies. Over 6200 syrphids are currently known and uncovering their phylogeny will help us to understand how these species have diversified, providing insight into an array of ecological processes, from the development of adult mimicry, the origin of adult migration, to pollination patterns and the evolution of larval resource utilization. Results: We present the first use of anchored hybrid enrichment in insect phylogenetics on a dataset containing 30 flower fly species from across all four subfamilies and 11 tribes out of 15. To produce a phylogenetic hypothesis, 559 loci were sampled to produce a final dataset containing 217,702 sites. We recovered a well resolved topology with bootstrap support values that were almost universally >95 %. The subfamily Eristalinae is recovered as paraphyletic, with the strongest support for this hypothesis to date. The ant predators in the Microdontinae are sister to all other syrphids. Syrphinae and Pipizinae are monophyletic and sister to each other. Larval predation on soft-bodied hemipterans evolved only once in this family. Conclusions: Anchored hybrid enrichment was successful in producing a robustly supported phylogenetic hypothesis for the syrphids. Subfamilial reconstruction is concordant with recent phylogenetic hypotheses, but with much higher support values. With the newly designed probe kit this analysis could be rapidly expanded with further sampling, opening the door to more comprehensive analyses targeting problem areas in syrphid phylogenetics and ecology.Peer reviewe

A Review of Environmental Pollution from the Use and Disposal of Cigarettes and Electronic Cigarettes: Contaminants, Sources, and Impacts

While the impacts of cigarette smoking on human health are widely known, a less recognized impact of tobacco product use and disposal is environmental pollution. This review discusses the current literature related to cigarette and e-cigarette contamination in the context of environmental sources and impacts, with a focus on the documented influences on biota, ranging from bacteria to mammals. Cigarette butts and electronic cigarette components can leach contaminants into soil, water, and air. Cellulose acetate cigarette filters comprising the butts are minimally degradable and are a source of bulk plastic and microplastic pollution, especially in aquatic ecosystems where they tend to accumulate. Cigarette combustion and aerosol production during e-cigarette use result in air contamination from sidestream, exhaled, and thirdhand pathways. The chemical byproducts of tobacco product use contaminate wastewater effluents, landfill leachates, and urban storm drains. The widespread detection of nicotine and cotinine in the environment illustrates the potential for large-scale environmental impacts of tobacco product waste. Studies show that cigarette butt leachate and nicotine are toxic to microbes, plants, benthic organisms, bivalves, zooplankton, fish, and mammals; however, there remain critical knowledge gaps related to the environmental impacts of tobacco product waste on environmental health and ecosystem functioning

Direct Measurement of Mercury Deposition at Rural and Suburban Sites in Washington State, USA

Because of mercury’s (Hg) capacity for long-range transport in the atmosphere, and its tendency to bioaccumulate in aquatic biota, there is a critical need to measure spatial and temporal patterns of Hg atmospheric deposition. Dry deposition of Hg is commonly calculated as the product of a measured atmospheric concentration and an assumed deposition velocity. An alternative is to directly assess Hg deposition via accumulation on surrogate surfaces. Using a direct measurement approach, this study quantified Hg deposition at a rural site (Pullman) and suburban site (Puyallup) in Washington State using simple, low-cost equipment. Dry deposition was measured using an aerodynamic “wet sampler” consisting of a Teflon plate, 35 cm in diameter, holding a thin layer (2.5 mm) of recirculating acidic aqueous receiving solution. In addition, wet Hg deposition was measured using a borosilicate glass funnel with a 20-cm-diameter opening and a 1 L Teflon sampling bottle. Hg deposition was estimated based on changes in total Hg in the aqueous phase of the samplers. Dry Hg deposition was 2.4 ± 1.4 ng/m2·h (average plus/minus standard deviation; n = 4) in Pullman and 1.3 ± 0.3 ng/m2·h (n = 6) in Puyallup. Wet Hg deposition was 7.0 ± 4.8 ng/m2·h (n = 4) in Pullman and 1.1 ± 0.2 ng/m2·h (n = 3) in Puyallup. Relatively high rates of Hg deposition in Pullman were attributed to regional agricultural activities that enhance mercury re-emission and deposition including agricultural harvesting and field burning. Hg concentration in precipitation negatively correlated with precipitation depth, indicating that Hg was scavenged from the atmosphere during the beginning of storm events. Because of their relative simplicity and robustness, direct measurement approaches such as those described in this study are useful in assessing Hg deposition, and for comparing results to less direct estimates and model estimates of Hg deposition

Effects of Nitrate Addition on Water Column Methylmercury in Occoquan Reservoir, Virginia, USA

Mercury bioaccumulation in aquatic biota poses a widespread threat to human and environmental health. Methylmercury (MeHg), the toxic form of mercury, tends to build up under anaerobic conditions in the profundal zones of lakes. In this study we performed a two-year assessment of spatial and temporal patterns of dissolved oxygen, nitrate, MeHg, manganese (Mn) and iron (Fe) in Occoquan Reservoir, a large run-of-the-river drinking water reservoir in Virginia, USA. A tributary to the reservoir receives input of nitrate-rich tertiary-treated wastewater that enhances the oxidant capacity of bottom water. Multiple lines of evidence supported the hypothesis that the presences of nitrate and/or oxygen in bottom water correlated with low MeHg in bottom water. Bottom water MeHg was significantly lower in a nitrate-rich tributary (annual mean of 0.05 ng/L in both 2012 and 2013) compared to a nitrate-poor tributary (annual mean of 0.58 ng/L in 2012 and 0.21 ng/L in 2013). The presence of nitrate and oxygen in bottom water corresponded with significantly lower bottom water MeHg at an upstream station in the main reservoir (0.05 versus 0.11 ng/L in 2013). In 2012 the reservoir exhibited a longitudinal gradient with nitrate and oxygen decreasing and MeHg and Mn increasing downstream. In both study years, there was a clear threshold of oxygen equivalent (3–5 mg/L), a metric that combines the oxidant capacity of nitrate and oxygen, above which MeHg (\u3c0.05 ng/L), Mn (\u3c0.3 mg/L) and Fe (\u3c0.5 mg/L) were low. Results indicated that the addition of nitrate-rich tertiary-treated wastewater to the bottom of anaerobic reservoirs can reduce MeHg concentrations, and potentially decrease mercury bioaccumulation, while increasing the safe water yield for potable use

Satellite Remote Sensing: A Tool to Support Harmful Algal Bloom Monitoring and Recreational Health Advisories in a California Reservoir

Abstract Cyanobacterial harmful algal blooms (cyanoHABs) can harm people, animals, and affect consumptive and recreational use of inland waters. Monitoring cyanoHABs is often limited. However, chlorophyll‐a (chl‐a) is a common water quality metric and has been shown to have a relationship with cyanobacteria. The World Health Organization (WHO) recently updated their previous 1999 cyanoHAB guidance values (GVs) to be more practical by basing the GVs on chl‐a concentration rather than cyanobacterial counts. This creates an opportunity for widespread cyanoHAB monitoring based on chl‐a proxies, with satellite remote sensing (SRS) being a potentially powerful tool. We used Sentinel‐2 (S2) and Sentinel‐3 (S3) to map chl‐a and cyanobacteria, respectively, classified chl‐a values according to WHO GVs, and then compared them to cyanotoxin advisories issued by the California Department of Water Resources (DWR) at San Luis Reservoir, key infrastructure in California's water system. We found reasonably high rates of total agreement between advisories by DWR and SRS, however rates of agreement varied for S2 based on algorithm. Total agreement was 83% for S3, and 52%–79% for S2. False positive and false negative rates for S3 were 12% and 23%, respectively. S2 had 12%–80% false positive rate and 0%–38% false negative rate, depending on algorithm. Using SRS‐based chl‐a GVs as an early indicator for possible exposure advisories and as a trigger for in situ sampling may be effective to improve public health warnings. Implementing SRS for cyanoHAB monitoring could fill temporal data gaps and provide greater spatial information not available from in situ measurements alone

Nonsingular Adsorption/Desorption of Chlorpyrifos in Soils and Sediments: Experimental Results and Modeling

At environmentally relevant concentrations in soils and sediments, chlorpyrifos, a hydrophobic organic insecticide, showed strong adsorption that correlated significantly with organic matter content. Chlorpyrifos desorption followed a nonsingular falling desorption isotherm that was estimated using a memory-dependent mathematical model. Desorption of chlorpyrifos was biphasic in nature, with a labile and nonlabile component. The labile component comprised 18–28% of the original solid-phase concentration, and the residue was predicted to slowly partition to the aqueous phase, implying long-term desorption from contaminated soils or sediments. The newly proposed mechanism to explain sorption/desorption hysteresis and biphasic desorption is the unfavorable thermodynamic energy landscape arising from limitation of diffusivity of water molecules through the strongly hydrophobic domain of soils and sediments. Modeling results suggest that contaminated soils and sediments could be secondary long-term sources of pollution. Long-term desorption may explain the detection of chlorpyrifos and other hydrophobic organic compounds in aquatic systems far from application sites, an observation that contradicts conventional transport predictions