Freshwater River Research Articles

Population Structure and Multidrug Resistance of Non-O1/Non-O139 Vibrio cholerae in Freshwater Rivers in Zhejiang, China.

To understand the environmental reservoirs of Vibrio cholerae and their public health significance, we surveyed freshwater samples from rivers in two cities (Jiaxing [JX] and Jiande [JD]) in Zhejiang, China. A total of 26 sampling locations were selected, and river water was sampled 456 times from 2015 to 2016 yielding 200 V. cholerae isolates, all of which were non-O1/non-O139. The average isolation rate was 47.3% and 39.1% in JX and JD, respectively. Antibiotic resistance profiles of the V. cholerae isolates were examined with nonsusceptibility to cefazolin (68.70%, 79/115) being most common, followed by ampicillin (47.83%, 55/115) and imipenem (27.83%, 32/115). Forty-two isolates (36.52%, 42/115) were defined as multidrug resistant (MDR). The presence of virulence geneswas also determined, and the majority of the isolates were positive for toxR (198/200, 99%) and hlyA (196/200, 98%) with few other virulence genes observed. The population structure of the V. cholerae non-O1/non-O139 sampled was examined using multilocus sequence typing (MLST) with 200 isolates assigned to 128 STs and 6 subpopulations. The non-O1/non-O139 V. cholerae population in JX was more varied than in JD. By clonal complexes (CCs), 31 CCs that contained isolates from this study were shared with other parts of China and/or other countries, suggesting widespread presence of some non-O1/non-O139 clones. Drug resistance profiles differed between subpopulations. The findings suggest that non-O1/non-O139 V. cholerae in the freshwater environment is a potential source of human infections. Routine surveillance of non-O1/non-O139 V. cholerae in freshwater rivers will be of importance to public health.

Assessing small-scale freshwater microplastics pollution, land-use, source-to-sink conduits, and pollution risks: Perspectives from Japanese rivers polluted with microplastics

Rivers are vital for understanding freshwater microplastics pollution, along with the conduits from land-sources to marine-sinks. In this study, we investigated microplastics in the small-scale Awano and Ayaragi rivers, which flow into the Sea of Japan (SJ), and the Asa and Majime rivers, which flow into the Seto Inland Sea (SIS) in Yamaguchi Prefecture, Japan. Surface water samples were collected from 29 stations. Filtration, wet peroxidation, and density separation methods were employed to extract microplastics. Polymers were identified via attenuated total reflectance-Fourier transform infrared spectroscopy. Microplastics abundances and comparisons among different rivers revealed that these small-scale rivers were highly polluted than others around the world. Characterization demonstrated that small microplastics (<1000 μm) in size, fibers and fragments in shape and the polymers—polyethylene, polypropylene, vinylon, polyethylene terephthalate, and polystyrene were dominant. These small-scale rivers emitted substantially higher quantities of Japan land-sourced microplastics (0.4–154.27 billions/day and 0.01–17.55 tons/day) into the SJ and SIS environments than larger rivers in other countries compared to basin areas. The pollution load index indicated that all the river stations were polluted with microplastics. An assessment of the polymeric and pollution risks revealed variably low to high risks. The higher were the abundances of microplastics and toxic polymers, the higher were the pollution level and risks. The sites at high risk of pollution were regarded as hotspots. Both point and non-point land-uses sources of pollution could release microplastics into the river freshwater environments, affected posing high risks and hotspots. Moreover, the pollution characteristics (shapes-sizes-polymers) indicated serious ecotoxicological threats to these rivers and their downstream environments. This study provided new insights into river microplastics pollution and revealed small-scale rivers to be prominent source-to-sink microplastics conduits. Risk assessments provided a baseline for future comprehensive assessments and developing practical approaches to wards setting water quality criteria, pollution control and management.

Understanding Membrane Fouling in Electrically Driven Energy Conversion Devices

Positively charged (cetylpyridinium chloride), negatively charged (sodium dodecyl sulfate), and non-charged (polyethylene glycol) surfactants are used as potential foulant in reverse electrodialysis systems supplying seawater and river freshwater. Fouling tendency of the foulants to ion-exchange membranes is investigated in terms of the adsorption by electromigration, electrostatic attraction, and macromolecule interaction in reverse electrodialysis systems. According to theoretical prediction of fouling tendency, charged foulants in seawater streams could foul ion-exchange membranes significantly. However, the worst fouling behavior is observed when the charged foulants are present in river streams. As a result of zeta potential measurement, it is found that the Debye length of the charged foulants decreases due to the higher ionic strength of seawater streams and causes to lower net electrostatic effect. It finally results in less fouling tendency in reverse electrodialysis.

The Hydrochemical Characteristics of a Stressed Sand-Gravel Aquifer: Kazan Plain, Ankara, Turkey

Over-exploitation and sand-gravel mining affect groundwater resources in terms of both quantity and quality. Groundwater level and well yields in and around the sand-gravel pits significantly decrease. Sand-gravel mining also changes the turbidity levels and temperature of groundwater. Reduction and destruction of valuable aquifers are significant issues. In this case, the natural state of the aquifer disappears. The Kazan Plain in central Turkey is a dramatic example of these kinds of results. The productive sand-gravel aquifer in the Kazan plain has been substantially damaged due to intensive sand-gravel mining since the 1980s. Additionally, over-exploitation has caused notable declines in groundwater levels, particularly in the 2000s. This study focuses on the hydrogeochemical situation of the Kazan Plain alluvium aquifer after intensive sand-gravel mining and over-exploitation. Groundwater samples were collected seasonally in 2015, five years after the over-exploitation and heavy sand-gravel mining. The decline reached 20 m (about half of the saturated thickness of the sand-gravel aquifer) in the region where the intensive groundwater abstraction lasted until 2010. Some quarries continued to operate until 2010, but after that mining activity continued only at a minimum level. Today, groundwater quality has been significantly degraded due to the over-exploitation of sand-gravel mining and also the cessation of recharge from fresh river water.

Natural history study of an understudied sea catfish species from Panama (Siluriformes: Ariidae)

ABSTRACT The semi-anadromous sea catfish species Cathorops tuyra (Ariidae, Besudo sea catfish) from the Tropical Eastern Pacific has been found reproductively active in the freshwater rivers and lakes of the Panama Canal. Despite growing concerns for biodiversity, reports on natural history are lacking for many Neotropical sea catfishes. We aimed to provide data on the diet and seasonal timing of spawning of C. tuyra for an autochthonous, semi-anadromous, brackish water population from Rio Santa Maria and an allochthonous freshwater non-migrating population from Rio Chagres, an affluent to the Panama Canal, to understand how changing from semi-anadromous to residential lifestyle affects the natural history of a species. Fish from both sampling sites were dissected and information on stomach content, size, weight, parasitic load, sex, maturity, and number of eggs were recorded. In Rio Chagres, there was a female bias and individuals were larger and in pre-spawning mode compared to Rio Santa Maria. Parasite prevalence was low in Rio Chagres and zero in Rio Santa Maria. The diets were very similar between populations: gastropods, bivalves, and insects were the most important prey items in both rivers representing a diverse omnivorous diet that is similar to that of other catfishes.

Ecological changes in geological media and Siverskyi Donets River basin under the condition of goal mines flooding

Complex economic, geological-technological state of coal mines and impact of the armed conflict factors (the breakdown of energy supply, objects of critical infrastructure, etc.) accelerated closure of coal mines by the method of “wet preservation” in particular. In most developed EU countries decommissioning of coal mines, which have great depth (up to 1,0-1,5 km) and areas of minefields, occurs according to the post-mining (PM) research and production complex, which is based on the scientific and technological activities regarding prevention of dangerous changes in the geological environment (GE) - subsidence of ground surface, lands flooding, emission of explosive and toxic gases as well as reduction of outflows of polluted water into the local river basins (RB) and the soil aquifer. Additionally, PM suggests some mining works turning into the hydraulic-filtration system of mine water retention at a depth of 250-350 m with a purpose of preventing pollution flow into the freshwater aquifers and river network, preserving regional aquitards, degassing of mountain surface. In general, the PM activities complex aims at maintaining the balance and protective potential of the GE as mineral and landscape basis of the biosphere, elimination of dangerous changes in ecological parameters of the hydrographical network. It is shown that new models of subsoil and water use, geological prospecting structure, scientific basis for permissible changes in GE and RB are required together with closure of “old” mining works (MW) and opening of new ones, improvement of the environment monitoring based on GIS technologies and Earth remote sensing.

Ecosystem Organic Carbon Stock Estimations in the Sile River, North Eastern Italy

River ecosystems are one of the dynamic components of the terrestrial carbon cycle that provide a crucial function in ecosystem processes and high value to ecosystem services. A large amount of carbon is transported from terrestrial to the ocean through river flows. In order to evaluate the contribution of Sile River ecosystem to the global carbon stock, the river ecosystem Organic Carbon (OC) stock was quantified for sediments and dominant submerged aquatic macrophytes (SAMs) during the two sampling periods at three different stations along the Sile River (North Eastern Italy). The total mean ecosystem OC stock was 95.2 ± 13.8 Mg C ha−1 while those of SAMs ranged from 7.0 to 10.9 Mg C ha−1 which accounted for approx. 10% of the total OC stock. The total aboveground biomass retains approx. 90% of the SAM carbon stock, with a mean of 8.9 ± 1.6 Mg C ha−1. The mean sediment OC stock was 86.6 ± 14.5 Mg C ha−1 with low seasonal variations among the sites. Indeed, various environmental parameters and hydrodynamics appear to affect the accumulation of OC within the river ecosystem. The results highlight the role that freshwater river ecosystems play in the global carbon cycle, which consequently provide a baseline for future river ecosystem monitoring programs. Furthermore, future studies with additional sites and seasonal surveys of the river will enhance our understanding of the effects of global climate change on the river ecosystem and improve the ecosystem services.

Characterising groundwater-surface water connectivity in the lower Gandak catchment, a barrage regulated biodiversity hotspot in the mid-Gangetic basin

The alluvial aquifer system of the Indo-Gangetic Basin (IGB) is one of the world’s most important freshwater resources, sustaining humans and river ecosystems. Understanding groundwater recharge processes and connections to meteoric and surface water is necessary for effective water resource management for human and wider ecological requirements. Parts of the mid-Gangetic Basin, across eastern Uttar Pradesh and Bihar, are characterised by stable long-term groundwater levels, high annual rainfall, and limited historical groundwater use compared to parts of Northwest India for example. In this paper we use a combination of environmental tracers and hydrograph observations to characterise sources of recharge and groundwater-surface water interaction using a transect approach across the catchment of the River Gandak, a major barrage-regulated tributary of the River Ganga. Stable isotope results show that the dominant source of groundwater recharge, in the shallow (0–40 m bgl) Holocene and underlying Pleistocene aquifer system (>40 m bgl), is local rainfall. The shallow Holocene aquifer is also supplemented by local recharge from river and canal seepage and irrigation return flow in the upper and mid parts of the catchment. These observations are corroborated by evidence from detailed groundwater hydrographs and salinity observations, indicating localised canal, river and lake connectivity to groundwater. In the middle and lower catchment, river discharge is dominated by groundwater baseflow during the peak dry season when barrage gates are closed, which contributes to ecological flows for endangered river dolphins and gharial crocodiles. Groundwater residence time tracers indicate active modern recharge in the shallow alluvial aquifer system across the catchment. In the shallow Holocene aquifer elevated arsenic (As), iron (Fe), and manganese (Mn) exceeded WHO drinking water guidelines in a minority of sites, and uranium (U) and fluoride (F) concentrations approach but do not exceed the WHO guideline values. These observations varied across the catchment with higher As, Fe and Mn in the upper and mid catchments and higher U in the lower catchment. Groundwater salinity was typically between 500 and 1000 μS/cm, and isolated higher salinity was due to recharge from flood-plain wetlands and lakes impacted by evaporation. At present, the Gandak catchment has relatively high rainfall and low abstraction, which maintains stable groundwater levels and thus baseflow to the river in the dry season. Potential future threats to groundwater resources, and therefore river ecology due to the sensitivity to changes in baseflow in the catchment, would likely be driven by reductions in local monsoon rainfall, changes in water management practices and increased groundwater use.

Three New Species of Rhinebothrium (Cestoda: Rhinebothriidea) from the Leopard Whipray, Himantura Leoparda, in Australia.

Examination of 4 specimens of the leopard whipray Himantura leoparda, a dasyatid stingray from northern Australia, led to the discovery of 3 new species of Rhinebothrium. Rhinebothrium leopardensis n. sp., Rhinebothrium nandoi n. sp., and Rhinebothrium ruhnkei n. sp. are described, increasing the diversity of the genus to 51 species globally. All 3 new species differ from their congeners in terms of testis number, proglottid number, loculus number, and size. With respect to one another, R. leopardensis n. sp. has bothridia that are weakly constricted at their centers and has a greater number of proglottids than the other 2 species (93-108 vs. 11-15, and 48-78, respectively). Rhinebothrium nandoi n. sp. is the smallest of the 3 species found in H. leoparda (3.6-5 vs. 10-15 mm and 10.1-15.8 mm in total length [TL], respectively) and bears bothridia that are constricted at their centers. Rhinebothrium ruhnkei n. sp. bears bothridia that are conspicuously constricted at their centers and has more testes than R. leopardensis and fewer than R. nandoi (7-10 vs. fewer than 7 and 21-33, respectively). Before this study, 56% (27 of 48) of Rhinebothrium species had been described from the freshwater river systems of South America and the marine waters surrounding South and North America. In contrast, despite the remarkably diverse nature of its batoid fauna, only 19 species were known from the Indo-Pacific region. Our work increases this number to 22, emphasizing the highly underestimated nature of Rhinebothrium diversity in this region of the globe. The discovery of these 3 new species was not unexpected, given the relatively poor status of our current knowledge of the cestode faunas of dasyatid stingrays in the Indo-Pacific region, and given the fact that it is common for a single batoid species to host 2 or more species of Rhinebothrium. Our results suggest that additional work on the cestode faunas of the batoids, especially dasyatids, from the Indo-Pacific region is likely to be highly productive in terms of contributing to the knowledge of Rhinebothrium diversity.

Characterization of Archaeological European White Elm (Ulmus laevis P.) and Black Poplar (Populus nigra L.)

The present study aims at characterization of freshly-cut and archaeological European white elm and poplar. The archaeological elm sample was buried at a depth of 8–10 m inside of soil with age approximation of ~1800–2000 years old, and the archaeological poplar sample was a part of a boat in a freshwater lake or river with age estimation of ~1000–1200 years. Alteration in the chemical structure of the elm and poplar samples due to the ageing process were confirmed by X-ray photoelectron spectroscopy (XPS). Both archaeological wood (AW) samples illustrated considerably lower cellulose crystallinity than the fresh samples as determined by X-ray diffraction. The sorption behavior of AW and fresh wood (FW) samples were evaluated by means of dynamic vapor sorption (DVS) analysis. Results exhibited a higher equilibrium moisture content (EMC) and sorption hysteresis values in archaeological elm and poplar as compared with the fresh samples. Higher hydrophilicity of the AW samples than the FW ones is attributed to their higher amorphous structure. The extensive degradation of AW samples were also confirmed by scanning electron microscopy (SEM) micrographs.

Complete mitogenome of Ganges river dolphin, Platanista gangetica gangetica and its phylogenetic relationship with other cetaceans.

The Ganges river dolphin, Platanista gangetica gangetica is one of the endangered cetaceans. Due to increasing anthropogenic activities, it has faced a significant reduction in distribution range since the late 1800s and has even gone extinct from most of the early localities. The investigation of complete mitogenome holds significant relevance for identifying evolutionary relationships and monitoring the endangered species. Herein, we report and characterize for the first time the 16,319bp complete mitochondrial genome of P. g. gangetica. It comprises 13 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA genes, and one control region (CR). The genome composition was A + T biased (59.6%) and exhibited a positive AT-skew (0.104) and negative GC-skew (- 0.384). All the genes were encoded on the heavy strand, except eight tRNAs and the ND6 gene. In the CR, an 18bp tandem repeat sequence was observed. Our Bayesian Inference (BI) and Maximum Likelihood (ML) based phylogenetic analysis indicated that studied river dolphins were polyphyletic and the placement of Platanista was to be more basal than other river dolphins (Lipotes, Inia and Pontoporia). The pairwise genetic distance of Platanista with other cetaceans was varied, with an overall close affinity with whales. The model-based BI and ML phylogenetic analysis indicated that Platanista clustering with Ziphiidae with high to moderate supportive values (PP/BP = 98/68). The results of this study provide insights important for the conservation genetics and further evolutionary studies of the freshwater river dolphins.

Development of a quantitative PCR-based method for studying temporal DNA degradation in waterlogged bone.

While several studies have examined temporal DNA degradation in bones collected from terrestrial environments, studies on temporal DNA degradation in bones collected from aquatic environments are limited and mostly based on case studies. The objective of this study was to assess the impact of long-term submersion, aquatic environment, bone type and DNA extraction method on DNA quality and quantity. Bone samples (scapulae and ribs), collected every ~1000 ADD from a freshwater lake and river, underwent DNA extraction via ChargeSwitch® gDNA Plant Kit and organic phenol-chloroform methods, and DNA quantitation using both TaqMan and SYBR Green-based quantitative PCR (qPCR) methods. Results suggest that in both bone types, quality of recovered DNA (i.e., degradation index) declined significantly with increase in submersion time. Among two bone types, quality of recovered DNA from scapulae declined faster than rib samples. There was no significant difference in recovered DNA quantity between bone types, DNA extraction methods, or locations but various interactions between these variables showed significant difference. Overall, it can be concluded that DNA can be extracted from waterlogged bone in sufficient quantity to generate an STR profile up to 4000 ADD.

Study of tidal effect on water mass stratification in Mahakam estuary using 3D hydrodynamic model

Mahakam Delta is a delta with unique characteristic. As a result of the continuous sedimentation process, the delta can be said as a complex delta because it has dozens of tributaries that are interconnected and flow into the sea to their estuaries. Mahakam Delta estuary is a meeting place for mixing masses of water from freshwater rivers and high salinity rivers. The aim of this study is to determine the water column stratification seen from the salinity and temperature parameters in the Mahakam Delta estuary. This study uses the ECOMSED model which is run for 40 days (July 7 to Augustt 16, 2018) with tides and river discharge as the generating force. The simulation results show that stratification is predominantly influenced by differences in salinity between the layers. The strongest stratification is located in the northern Mahakam Delta line with a difference in salinity is 8 psu from surface to bottom layer.

Quasi‐Biweekly Mode of the Asian Summer Monsoon Revealed in Bay of Bengal Surface Observations

AbstractAsian summer monsoon has a planetary‐scale, westward propagating “quasi‐biweekly” mode of variability with a 10–25 day period. Six years of moored observations at 18°N, 89.5°E in the north Bay of Bengal (BoB) reveal distinct quasi‐biweekly variability in sea surface salinity (SSS) during summer and autumn, with peak‐to‐peak amplitude of 3–8 psu. This large‐amplitude SSS variability is not due to variations of surface freshwater flux or river runoff. We show from the moored data, satellite SSS, and reanalyses that surface winds associated with the quasi‐biweekly monsoon mode and embedded weather‐scale systems, drive SSS and coastal sea level variability in 2015 summer monsoon. When winds are calm, geostrophic currents associated with mesoscale ocean eddies transport Ganga‐Brahmaputra‐Meghna river water southward to the mooring, salinity falls, and the ocean mixed layer shallows to 1–10 m. During active (cloudy, windy) spells of quasi‐biweekly monsoon mode, directly wind‐forced surface currents carry river water away to the east and north, leading to increased salinity at the moorings, and rise of sea level by 0.1–0.5 m along the eastern and northern boundary of the bay. During July–August 2015, a shallow pool of low‐salinity river water lies in the northeastern bay. The amplitude of a 20‐day oscillation of sea surface temperature (SST) is two times larger within the fresh pool than in the saltier ocean to the west, although surface heat flux is nearly identical in the two regions. This is direct evidence that spatial‐temporal variations of BoB salinity influences sub‐seasonal SST variations, and possibly SST‐mediated monsoon air‐sea interaction.

Cultural and Religious Tourism in Majuli With Special Reference to Auniati Sattra And Uttar Kamalabari Sattra

The paper attempts to study the potential of cultural and religious tourism industry in Majuli as a whole and Auniati Sattra and Uttar Kamalabari Sattra of the island in particular. The scope of tourism in Majuli, be it eco-tourism or religious tourism and cultural tourism is tremendous with nature’s opulence in full display here. Majuli, renowned as one of the world’s largest freshwater river island is a conglomeration of Vaishnavite religion, natural beauty, art and craft, ethnic culture and traditions which needs to be explored and showcased to the world. The Sattras (Vaishnava monasteries) and their rich heritage and cultures have given Majuli the status and pride of being the “Cultural Capital of Assam”. Today people have shifted from the traditional ways of touring in the form of going to hill stations, historical places etc. to more adventurous and unexplored destinations. Adding to the other attractions of northeast India, Majuli stands out as a jewel in the crown with its total package of natural beauty, religious monasteries, eco-tourism etc. An attempt has been made to present the uniqueness of Majuli’s Sattras, its different congregational prayer services, a distinct dance form called Sattriya and an about to be an extinct art form mask making as a potential tool to put Majuli in the tourist map of India and the world.

Dissolved neodymium and hafnium isotopes and rare earth elements in the Congo River Plume: Tracing and quantifying continental inputs into the southeast Atlantic

The Congo River is the second largest river by discharge in the world and a major source of element inputs into the South Atlantic Ocean. Yet, the element fluxes and transport mechanisms across and beyond its estuary and their impacts on the marine distribution and cycling of many major and trace elements are not well understood. We present the first combined dissolved neodymium (Nd) and hafnium (Hf) isotope and rare earth element (REE) concentration distributions following the Congo River plume along its flow path off the West African coast and along a connected offshore latitudinal section at 3°S. The Congo River freshwater itself is characterized by extraordinarily high Nd and Hf concentrations of up to 4000 pmol/kg and 54 pmol/kg, and by Nd (εNd) and Hf (εHf) isotope compositions that range between −15.6 and −16.4 and between 0.35 and −1.4, respectively. Our near- and offshore data indicate that at salinities above 23 conservative mixing of Congo-derived Nd and Hf concentrations and isotopic signatures with ambient surface seawater occurs for at least 1000 km to the northwest of the river mouth. This demonstrates a large spatial extent of the influence of the Congo plume on trace metal distributions in the eastern south Atlantic surface waters. A comparison between dissolved Nd and Hf fluxes from the Congo River and the shelf zone estimated based on radium isotope compositions indicate that release from Congo-derived particulate phases likely balances strong estuarine REE and Hf removal in the low salinity zone. The combined riverine and shelf zone flux for Nd is almost twice as high as that estimated for the Amazon River, despite that the Amazon discharge is about five times higher than that of the Congo River. Even the offshore Nd flux estimated for the 3 °S transect based on radium isotope compositions still corresponds to ∼40% of the Congo-shelf-zone flux and reaches 150 ± 50 Mg/year for Nd. Moreover, intermediate waters below the plume are strongly affected by exchange with particulate inputs from the Congo River given that Nd isotope signatures are inconsistent with values expected from large-scale water mass mixing and instead support unradiogenic Nd release either from sinking or deposited Congo-derived detrital material. Deep and bottom water isotopic signatures are also slightly affected by interaction with particles and benthic Nd release.

Research progresses and prospects of microplasticsin the environment

<p indent=0mm>The term “microplastics” (MPs) refers to fine plastics less than <sc>5 mm</sc> in size and includes primary sources from the original production of small-sized particles and secondary sources from the degradation or fragmentation of large plastics. MPs have been widely detected in marine (estuaries, bays, coastal zones, deep seas, ocean waters and sediments), soils (farmlands, urban soils, wetlands, landfill and polar areas), freshwater (lakes, rivers, reservoirs, snow and ice, and sewage treatment plants) and sediments, atmosphere (outdoor and indoor airs), living organisms (plants, animals, microorganisms, human and pet faeces), and foods (table salts, drinking waters, beers, vegetables and pet foods). Besides, MPs could be acted as the vector for many environmental pollutants, pathogens and even antibiotic resistance genes (ARGs). Moreover, MPs can be taken up by various terrestrial and aquatic organisms and transfer along the food chain at various trophic levels. Thus, environmental MP pollution is becoming one of the most serious threats to the Earth’s surface ecosystems which has attracted serious concern and extensive research by many governments and the scientific community worldwide. Up to now, comprehensive studies and reports on the latest multidisciplinary research progress on microplastics in multiple environmental media remain limited. From the perspectives of earth sciences, chemistry, biology, and management, this article systematically reviews the research progress on the abundance, distribution and sources of microplastics in the waters, soils, atmosphere, sediments and organisms; the separation and analytical methods of microplastics in multiple environmental media; the migration and prediction of microplastics in terrestrial, marine and atmospheric environments; the surface changes and biofilm formation on microplastics and their adsorption characterization of environmental pollutants, pathogens and ARGs; the biological uptake, accumulation and ecological risks of MPs; the food chain transfer and health risks of MPs; the physico-chemical fragmentation and biodegradation of MPs in the environment and their risk reduction strategies and techniques. Finally, the key scientific issues and future research directions of environmental microplastics are also proposed in this review, such as methdology breakthroughs in separation and identification of submicron and nanoscale microplastics; comprehensive study on the distribution, migration, transport and flux of microplastics in environmental multi-media at cross-reginal and global scale; comprehensive monitoring, quantitative characterization and long-term evaluating the impacts of environmental microplastics on ecosystems; and the systematic assessment of human health risks of microplastics to different populations.

The direct and indirect effects of land use and water quality on phytoplankton communities in an agriculture-dominated basin.

Understanding the factors that control biodiversity in rivers is challenging due to the variety of potential sources, linkages, and processes. This research assesses the effects of land use on phytoplankton communities across water quality gradients. By employing abiotic and biotic datasets of 149 catchments in Lake Chaohu basin, China, and a structural equation model (SEM), the direct and indirect effects of land use and water quality on phytoplankton dynamic were analyzed. Both land use and water quality had statistically significant direct effects on phytoplankton community attribute and diversity, although these effects differed among these indices. For instance, farmland was found to positively affect the abundance and diversity indices, while total nitrogen (TN) had significant positive effects on species richness and abundance. Importantly, the average indirect effects strengthened the effects of land use (e.g., built-up land and woodland) up to 82.4% mainly through nutrients, while the average indirect effects weakened the effects of land use (e.g., farmland) by as much as 49.9% mainly due to nutrients, thus indicating the prevailing role of the effects of land use on phytoplankton based on nutrient concentrations. The results suggest that nutrients can regulate the effect of land use on phytoplankton community attribute and diversity indices. This study highlights the advantages of using an SEM because the potential linkages for phytoplankton diversities are more likely to be identified with this method than with a classical linear regression model. Therefore, SEM has wide application prospects in the field of the conservation of biodiversity in freshwater rivers.

Post-mining of the Ukraine’s mining regions as a new direction for the environmentally safe use of mineral resources

The growth of market requirements for socio-economic and environmental parameters of mineral resources in most developed (“old”) mining areas (MA) of Ukraine has led to the closure of mines and quarries, including by the method of “wet conservation” (autorehabilitation uncontrolled flooding). This process is most actively developing in the MA of the Donbas, including in areas affected by armed conflict.&#x0D; In most developed EU countries, the decommissioning of coal mines (Ruhr, Lorraine, Wales), which have large depths (up to 1,0–1,5 km) and area (thousand sq. km) of minefields, is a research and production complex of post-mining (PM), which is based on scientific and technical measures to prevent dangerous changes in the geological environment (GE) - subsidence of the earth’s surface, flooding of lands, release of explosive and toxic gases, limiting the leakage of polluted water. In addition, the PM provides for the transformation of part of the mine workings into a hydraulic filtration system of mine water retention at a depth of 250–350 m in order to prevent the flow of pollutants into freshwater horizons and river network, preservation of regional aquicludes, degassing of mining space. In general, the set of PM measures is aimed at maintaining the balance and protective potential of the GE as a mineral and landscape base of the biosphere.&#x0D; In this regard, the article compares the protective potential of the GE of the Chornobyl accident zone and the Donbas region, as well as performs an expert assessment of the environmental protection potential of the PM in the leading MA of Ukraine.&#x0D; It is shown that a new model of mineral resourses use, structure of geological exploration works, scientific substantiation of maximum allowable changes of GE at closing of “old” and formation of new MA, improvement of environmental monitoring based on GIS technologies and remote sensing of the Earth are needed.

Naegleria Fowleri Diagnosed with Hospital Autopsy in a Toddler: A Case Study

Abstract Casestudy Naegleria fowleri, an amoeba, is typically found in warm freshwater lakes, ponds, rivers and hot springs. It is responsible for causing the incredibly rare and lethal central nervous system infection called Primary Amoebic Meningoencephalitis (PAM). In the United States, 145 confirmed cases have been documented since 1962. Most cases are associated with freshwater lakes, ponds and reservoirs, while only a handful have been linked to artificial recreational venues such as pools, interactive water play-grounds, and spas. In addition to highlighting a rare amoebic disease, this case illustrates the continued importance of hospital autopsies especially given recent ruling to eliminate the autopsy requirement by the Centers for Medicare and Medicaid Services. Results An otherwise healthy toddler had upper respiratory symptoms and otitis media days after returning from an artificial recreational water venue, becoming increasingly lethargic and febrile over the next few days. At the hospital, cerebrospinal fluid (CSF) abnormalities were suggestive but not consistent with bacterial meningitis. A meningoencephalitis panel, a Computed Tomograph (CT) scan of the head, and chest-x-ray were negative for abnormalities. Appropriate antimicrobial therapy was initiated. Three days after hospital admission, his symptoms worsened including development of dysconjugate gaze and signs of cerebellitis. He became increasingly hemodynamically unstable, suffered an arrest, and passed away days later. Conclusion Since this death did not fall under the state’s statutes mandating medicolegal autopsy, a hospital- requested autopsy was performed. Cerebral edema and a light gray to light green exudate was along the inferior and lateral left temporal lobe, brain stem, and cerebellum. An exuberant lymphoplasmacytic infiltrate with scattered polymorphonuclear leukocytes expanded the meninges. Small histiocyte-like cells with distinct eccentric nuclei and granular, vacuolated cytoplasm, confirmed by Centers for Disease Control and Prevention (CDC) to be Naegleria fowleri, were best visualized in the Virchow-Robin spaces and deeper parenchyma.