Water Stations Research Articles

Seasonal dynamics of Herohalli Lake in North Bangalore, Karnataka, India: A limnological study of water stations and its impact on a vertebrate biological system

Aim: This study takes a novel approach, aiming to assess the seasonal dynamics of limnological variables and the ecological health of Herohalli Lake using the embryos of Danio rerio. Methodology: Water samples from three sampling sites, the open surface, deposit and inlet, were tested for physical, chemical, and biological parameters following the standard methods of APHA. This comprehensive assessment, conducted between June 2022 and July 2023, spanned the monsoon, autumn, winter, spring, and summer seasons. Developmental stages of D. rerio embryos were observed, and their heart rates were counted and compared between the sampling sites. Results: The study revealed significant limnological changes influenced by seasons at all sampling stations. The open surface water station showed superior results to deposit and inlet sites. Notably, the study found that the water quality in the three stations moderately influence the aquatic life. Interpretation: Herohalli Lake plays a crucial role in the region's microclimate. This study recommends sustainable management, strategic planning, and policy-making to conserve the aquatic ecosystems efficiently. Key words: Herohalli Lake, Heartbeat count, Limnology, Zebrafish

Using Dominant Phytoplankton as Assessment of Water Quality: Water Resource Case Studies of University in Chatuchak District

The use of dominant phytoplankton as a water quality indicator was studied. Samples from 6 stations (S1-S6) were collected. From the study, 6 divisions of 34 genera of phytoplankton, i.e. Euglenophyta, Chlorophyta, Bacillariophyta, Chromophyta, and Pyrrhophyta were found, and the significant phytoplankton genera were Euglena, Phacus, and Tetraedron. By analysing water quality assessment in terms of scores by AARL-SPP Score using these three dominant genera, it was found that stations S1–S4 had a moderate level of water quality and stations S5–S6 had a moderate-polluted level of water quality. When the relationship between phytoplankton species and the water quality parameters were analysed by stepwise multiple regression analysis, the results showed that the prominent genus Merismopedia of Cyanophyta (Blue-green algae), correlated with transparency, salinity, chlorophyll a, and soluble phosphate while the genus Oscillatoria correlated with the total suspended solids, Chlorophyll a content, transparency, pH, temperature, and ammonia-nitrogen. The correlation indicates the high rate of phytoplankton growth was due to reduced water quality. According to water quality standards for surface water, the water quality was classified in Category 3.

Recent Findings on the Pollution Levels in the Romanian Black Sea Ecosystem: Implications for Achieving Good Environmental Status (GES) Under the Marine Strategy Framework Directive (Directive 2008/56/EC)

This study provides a comprehensive evaluation of contamination levels in the Romanian Black Sea within the framework of the Marine Strategy Framework Directive (MSFD). Over the course of five oceanographic expeditions between 2020 and 2022, data were gathered from 70 stations in transitional, coastal, shelf, and offshore waters of the Black Sea. Analyses were conducted on water, sediment, and biota samples for key contaminants: heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) such as organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs). The assessment identified contamination hotspots near riverine inputs, urban runoff, harbor activities, and industrial discharges. Offshore waters also showed measurable pollutant levels, likely from diffuse sources and atmospheric deposition. The key findings reveal the widespread contamination of HMs, PAHs, and POPs across the Romanian Black Sea, with concentrations in certain areas exceeding acceptable environmental thresholds, highlighting ongoing challenges for regional pollution management. PAHs were prevalent in both nearshore and offshore regions, while OCPs and PCBs were detected across various matrices, with significant concentrations observed in water and biota samples. The study emphasizes the importance of integrated assessments within the MSFD framework, suggesting that future evaluations should complement the “one out-all out” (OOAO) approach with multi-metric tools, to enhance the robustness of pollution status reporting. Despite improvements in some areas, contamination remains a critical challenge, requiring strengthened regulations, improved waste management, and increased regional cooperation to mitigate the ongoing risks to marine ecosystems. The findings provide valuable data for the upcoming national MSFD assessment cycle (2018–2023) and highlight the need for sustained monitoring and coordinated efforts to ensure long-term marine sustainability.

Water First School Water Promotion and Access Intervention: A Cost Analysis Study

BackgroundAdequate water intake is associated with improved cognitive and physical performance, prevention of dental caries, and overweight and obesity. However, access to free drinking water in schools remains inadequate. Water First, a school-based intervention promoting water consumption, was shown effective in preventing overweight, yet its costs have not been quantified. ObjectiveTo evaluate the costs of Water First from the school's perspective over 1 academic year. DesignSecondary analysis of a cluster-randomized clinical trial assessing the cost of Water First. Participants and settingSix public schools in the San Francisco Bay Area during the 2018-2019 academic year, with an average of 578 ± 69 students per school and 110 ± 2 fourth-grade students in intervention schools, and 508 ± 190 students per school and 101 ± 5 fourth-grade students in control schools. InterventionSchools were randomized to receive water dispensers and stations in cafeterias and high-traffic areas and a schoolwide water promotion campaign (school-level intervention). Fourth-grade students and teachers received reusable water bottles, lessons, and materials for school and home (class-level intervention). Main outcome measuresActivities, resources, and the value needed to implement the school-level and classroom-level intervention were systematically captured over 1 academic year, including labor, materials, and utilities costs. Statistical analysisThe intervention costs per school and per student were estimated by summing the component-specific costs. Results are presented for both school-level and classroom-level interventions in 2023 US dollars. ResultsThe Water First intervention costs $20 per student for the school-level and $131 per student for the classroom-level intervention over 1 academic year. Accounting for the useful life of the installed water stations and dispensers beyond 1 year, the annualized cost of the school-level intervention was $11 per student. ConclusionsThese cost estimates provide useful insights for schools and stakeholders to plan and implement effective school-based interventions that promote access to drinking water.

Risk assessment for the surface water quality evaluation of a hydrological basin

This paper proposes a risk assessment methodology for evaluating the surface water quality of hydrological basins based on physico-chemical parameter concentrations. Considering the Douro River basin in Portugal and monthly recorded dissolved oxygen and conductivity parameter measurements in 18 water sampling stations from January 2002 to December 2013, the work intends to answer the research question of identifying the riskiest periods for water pollution in the year and classifying the water sampling stations in terms of risk for water pollution. The methodology consists first in determining the pollution risk implied by the physico-chemical parameters, based on the monthly water station measurements, using six different risk measures, namely mean, variance, loss probability, entropy, mean excess loss and value at risk. The risk values are ordered according to each risk measure and a final ranking is established through a ranking aggregation method. The final ranking permitted identifying the high risk period as ranging from May to October and the low risk period from November to April. Furthermore, July was classified as riskiest month concerning the dissolved oxygen concentration, and August as riskiest month regarding the conductivity levels. On the other hand, the ranking allowed classifying the water sampling stations, previously grouped in clusters, in terms of similar risk for water pollution: six sampling stations in the west of the basin formed the riskiest cluster in the dry period considering the dissolved oxygen concentrations, and four of those stations formed also the riskiest cluster concerning the conductivity levels.

Microbial source tracking and identification of fecal contamination patterns in saltwater estuaries between base- and storm-flow events using dual genome-based approaches

Fecal contamination from natural and anthropogenic sources poses significant threats to saltwater estuaries, particularly after storms or heavy rainfall. Monitoring fecal contamination is essential for protecting these vulnerable ecosystems having important ecological and economic values. In this study, we investigated the abundance, sources, and potential causes of fecal contamination at three marine and seven freshwater stations across Vaughn Bay (WA, USA), a shellfish growing district, during base- and storm-flow events. Additionally, we evaluated the performance of fecal indicator bacteria (FIB) quantification, optical brightener assessment, and qPCR analysis for fecal contamination quantification. We compared the effectiveness of qPCR-based microbial source tracking (MST), which targeted a broad range of hosts including, such as humans, birds, cows, horses, ruminants, dogs, and pigs, with sequencing-based MST in identifying fecal contamination sources. Both MST analysis approaches identified birds and humans as the primary sources of fecal contamination. For marine water stations, freshwater creeks VBU001, VBU002, and VB047, along with drain VB007, were identified as the main sources of human-derived fecal contamination in Vaughn Bay, based on Kendall's tau analysis (τ: 0.58–0.97). This information indicates that the septic systems in the catchment areas of these creeks and drains require further investigation to achieve effective fecal contamination control. Optical brightener, FIB enumeration and qPCR quantification results were generally higher during storm-flow events, although they showed poor correlation with each other (Pearson r < 0.40), likely due to physiological and phylogenetic differences among the target organisms of these methods. However, the sequencing-based method faces challenges in precise quantitative identification of differences in fecal contamination between base- and storm-flow events. Due to its high-throughput and cost-effectiveness, we recommend using sequencing-based analysis for large-scale identification of the primary sources of fecal contamination in water environments, followed by targeted qPCR quantification of MST markers for more precise assessments.

Environmental DNA sheds new insight on molecular adaptation of foraminifera to temperature from laboratory-controlled culture experiment.

Foraminifera is the most important temperature proxy of the ocean on long time scales. However, the absence of temperature-controlled experiments at different water depths hinders the advancement of paleotemperature reconstruction with foraminifera from the continental shelf. For the first time, this study investigated the response of benthic foraminifera to temperature change using microcosm culture and metabarcoding. Foraminiferal communities from three continental stations at varying water depths (6.0, 9.2, and 26.0 m) were cultured under five temperature gradients (6, 12, 18, 24, and 30°C), with each treatment performed in triplicate. The foraminifera were fed with microalgae every 4 days, and the filtered seawater (through 0.22 μm pores), acting as a medium, was changed accordingly. The experiment lasted for 80 days, and 47 DNA samples were obtained and analyzed, including three insitu samples. The results showed that foraminifera adjusted its growth rate within the low-temperature range and adopted an r-strategy to cope with high-temperature stress. In addition, the foraminifera from deeper water stations exhibited a pronounced vulnerability to diminishing read counts. The read counts, operational taxonomic units (OTU) counts and Margalef index of foraminifera and the read counts of Rotaliida exhibited a remarkably positive correlation with temperature. The recommended relationships were described as read counts = 1314.75*T + 44754.51; OTU counts = 1.13*T + 44.26; Margalef index =1.13*T + 44.26. This study established the first quantitative relationship between temperature and foraminifera molecular parameters that holds significant implications for long-time paleotemperature calibration in climate change.

Community Structure, Abundance and Ecological Index of Phytoplankton in Jembrana Coastal Waters, Bali

Phytoplankton is an important component in aquatic ecosystems. Apart from producing oxygen, phytoplankton also act as primary producers in the food chain. Bali Sardinella (Lemuru) is an important fishery commodity in the Bali Strait, which is known to eat plankton (Plankton Feeder), so its existence depends on the distribution of plankton. This descriptive research aims to determine the community structure, abundance and ecological index of phytoplankton in the coastal waters of Jembrana Regency. Sampling was conducted in July 2023 at five observation stations in the coastal waters of Jembrana Regency (Pengambengan Beach, Perancak Beach and Delod Berawah Beach). Around 250 litres of seawater was filtered by a plankton net measuring 35 mm. The filtered samples collected in a 100 ml collecting bottle were then transferred to a 120 ml sample bottle and preserved in 4% formalin. The samples obtained were taken to the laboratory for observation under a microscope. This research shows that 66 types of phytoplankton were found to belong to 5 classes in the waters of Jembrana, Bali. The Bacillariophyceae class were found with the highest number of species (44 species), followed by the Dinophyceae (19 species), Chlorophyceae (1 species), Cryptophyceae (1 species), and Cyanophyceae (1 species). Based on the results of calculating phytoplankton abundance, various abundance values ​​were obtained at each observation station. Station 2 has the highest abundance of phytoplankton with 297 individuals/l followed by Station 1 (221 individuals/l), Station 4 (130 individuals/l), Station 3 (127 individuals/l), and Station 5 (36 individuals/l). The species Diversity Index (H') ranges from 2.61 - 2.83, the Dominance Index (C) ranges from 0.07 - 0.13, and the Evenness Index (e) ranges from 0.72 - 0.95. The ecological index value shows that the phytoplankton community in Jembrana coastal waters included in the moderate diversity category is not dominant and evenly distributed. The ecological index value shows that the water quality is categorized as moderately polluted.

Underwater noise measurements of a free-running ship model

ABSTRACT The high background noise and narrow widths of towing tanks, which cause sound wave reflections, make them unsuitable for noise measurements, leading to a lack of published hydroacoustic data. To address this, we developed a free-running test model of the benchmark DTC container ship at a 1/80 scale and conducted hydroacoustic tests in the artificial lake at Istanbul Technical University. The model was remotely controlled to pass a fixed water station equipped with a hydrophone. We present ship noise measurements at three different velocities, noting a strong correlation between the propeller rotation rates from self-propulsion tests and hydroacoustic signals at high speeds. However, accuracy decreases at lower speeds due to background noise interference.

Evaluation of LoRa Network Performance for Water Quality Monitoring Systems

Conserving water resources from scarcity and pollution is the basis of water resource management and water quality monitoring programs. However, due to industrialization and population growth in Malaysia, which have resulted in poor water quality in many areas, this program needs to be improved. A smart water quality monitoring system based on the internet of things (IoT) paradigm was designed to analyze water conditions in real time and enable effective water management. Long-range (LoRa) application of the low-power, wide-area networking concept has become a phenomenon in IoT smart monitoring applications. This study proposes the implementation of a LoRa network in a water quality monitoring system-based IoT approach. The LoRa nodes were embedded with measuring sensors pH, turbidity, temperature, total dissolved solids, and dissolved oxygen, in the designated water stations. They operate at a transmission power of 14 dB and a bandwidth of 125 kHz. The network properties were tested with two different antenna gains of 2.1 dBi and 3 dBi, with three different spread factors of 7, 9, and 12. The water stations were located on the Sungai Pantai and Sungai Anak Air Batu rivers on the Universiti Malaya campus, Malaysia. Following a dashboard display and K-means analysis of the water quality data received by the LoRa gateway, it was determined that both rivers are Class II B rivers. The results from the evaluation of LoRa performance on the received strength signal indicator, signal noise ratio, loss packet, and path loss at best were −83 dBm, 7 dB, &lt;0%, and 64.41 dB, respectively, with a minimum received sensitivity of −129.1 dBm. LoRa has demonstrated its efficiency in an urban environment for smart river monitoring purposes.

Combined solar and ground source heat pump heating system with a latent heat storage tank as a sustainable system to replace an oilfield hot water station

Present study focuses on a clean energy replacement for an oilfield hot water station and develops a combined solar and ground source heat pump (GSHP) heating system with a latent heat storage tank (LHST). The effects of LHST and heat replenishment on energy and coefficient of performance (COP) are quantitatively analyzed during short-term or long-term operation of the system. The suitability of three different phase change materials for the system is compared, and the optimal one is identified. Results show that the LHST with 70 °C melting point can increase the collector efficiency to 53.91 % and reduce the total energy consumption of the system by 52344 kWh. Heat replenishment could effectively mitigate the ground temperature drop to 0.19 °C/year, reducing the annual energy consumption of GSHP by more than 4230 kWh and providing an additional thermal energy of 72 GJ. Compared to the initial heating system, the novel system efficiency increases to 51.25 %. Gas consumption and total system energy consumption decreased by 81.7 % and 75.2 %, respectively. Annual reduction of CO2 emission is about 1150 tons, showing satisfactory performance. Outcomes of this study prove the application of clean energy in oil field industrial processes, and help in achieving the goals of emission reduction and carbon neutrality.

Peculiarities of seasonal dynamics of net primary production and its microzooplankton grazing in the coastal waters of the Black Sea (Sevastopol region)

The studies of net primary production (NPP) seasonal dynamics, its microzooplankton grazing were conducted at two stations in the western Black Sea coastal waters near Sevastopol during a period from January 2020 to December 2022. Each year, one maximum of the phytoplankton NPP (280–820 mg C·m-3·day-1) was observed in July, when the water temperature ranged from 22 to 25 °C, and solar radiation intensity was 48–50 E·m-2·day-1. Large diatoms and dinoflagellates played a key role in its formation. At this time, the values of the net phytoplankton growth rate were 0.3–1.0 day-1, and the relative share of primary production consumed by microzooplankton (g/m) did not exceed 26%. In December – February, when the water temperature was 8.0–13.5 °C and the intensity of solar radiation was 10–15 E·m-2·day-1, the NPP decreased to a minimum (4–38 mg C·m-3·day-1). Under these conditions, the net phytoplankton growth rate decreased to 0–0.40 day-1, and g/m was 15–100%. For three years at station 2, the contribution of large algae with cell volumes from 4000 to 18000 µm3 in the NPP was significantly higher than at station 1. It was 61.1 % in 2020, 69.7 % in 2021 and 23% in 2022. The consumed NPP for this size group of algae was 54 % in 2020, 68.4 % in 2021 and 47.8 % in 2022.

Analisis Kepuasan Pasien Terhadap Kualitas Pelayanan Rawat Jalan Rumah Sakit X Menggunakan Service Quality Metode Costumer Statisfaction Index (CSI) dan Importance Performance Analysis (IPA)

This study aims to evaluate the level of customer satisfaction with outpatient services at Hospital X and identify areas that require improvement. The results of data processing show that the customer satisfaction index (CSI) value obtained is 76.435%, which is included in the "Satisfied" category. However, there are still a number of patients who are dissatisfied with the services they receive, so efforts are needed to improve the quality of outpatient services. Meanwhile, the results of further analysis using the importance performance analysis (IPA) method reveal attributes that require special attention. The attributes are in Quadrant I of the Cartesian IPA diagram, which shows improvement priorities. Recommendations for improvement include adding facilities such as drinking water stations, children's play areas, and spare chairs for patients queuing. Apart from that, it is necessary to design standard operating procedures (SOP) that are in accordance with doctors' schedules to avoid schedule conflicts, as well as regular training regarding service excellence for medical personnel and hospital staff. The implementation of these recommendations is expected to increase patient satisfaction with outpatient services at Hospital X.

Rainfall and Extreme Drought Detection: An Analysis for a Potential Agricultural Region in the Southern Brazilian Amazon

In recent decades, the main commercial crops of Mato Grosso, such as soybeans, corn, and cotton, have been undergoing transformations regarding the adoption of new technologies to increase production. However, regardless of the technological level, the climate of the region, including the rainfall regime, can influence the success of crops and facilitate, or not, the maximum production efficiency. This study aimed to define the behavior of the variability in monthly and annual rainfall and its probability of monthly occurrence and calculate the drought index for the northwestern region of Mato Grosso, in the southern region of the Brazilian Amazon. To carry out the study, daily rainfall records were collected, calculating the totals for each month of the historical series for each of the four National Water and Sanitation Agency (ANA) rain gauge stations, Aripuanã (1985–2020), Colniza (2001–2020), Cotriguaçu (2004–2020), and Juína (1985–2020), representing the northwestern region. The annual distribution of rainfall during the periods studied ranged from 1376.2 to 3017.3 mm. The monthly distribution indicated a typical water shortage in the months of June, July, and August. The probability of rainfall near the average for each month was more than 50%. The monthly SPI-1 index revealed a total of 56 months affected by very dry events and 34 extreme dry events. The annual SPI-12 index pointed to seven very dry years and five extremely dry years. Therefore, the region presented high rainfall rates in most years; however, a significant process of drought was also observed, including in rainy months, which are the periods with the greatest demand for the main agricultural crops.

Hubungan Kepadatan Gafrarium pecinatum dengan Kualitas Perairan di Perairan Pengudang dan Perairan Dompak, Tanjungpinang Provinsi Kepulauan Riau

This study aims to analyze the relationship between macrozoobenthos Gafrarium pecinatum density and water quality at two water stations determined based on the turbidity of the research location on Sunday, May 26, 2024 in Pengudang waters and Monday, May 27, 2024 in Dompak waters. Field data analysis was carried out in the Marine Biology laboratory of the Faculty of Marine Science and Fisheries UMRAH. This study used a random sampling method with sample collection carried out at two predetermined research stations. The results showed that Gafrarium pecinatum is a macrozoobenthos species found in both research locations, with differences in the number of individuals between stations. Evaluation of water quality showed that most of the chemical and physical parameters were still within the established quality standard limits, but the temperature parameter at station 2 slightly exceeded the quality standard limits. Nonetheless, the water conditions at both sites can still be considered suitable to support the life of marine biota. Further monitoring is required to maintain the sustainability of the coastal ecosystem.

Zoo Benthic Biodiversity as a Bioindicator in the Bengawan Solo Estuary

Graphical Abstract Highlight Research Salinity is the critical influencing the distribution of macrobenthos species based on habitat (seawater and freshwater species) in estuaries. The brackish water station exhibited the highest macrobenthos abundance, whereas the seawater station showed the highest meiobenthos abundance. Corresponding water quality parameters markedly influenced the abundance of each benthic group. The calculation of abundance and biological indexes classified the Bengawan Solo estuary as relatively stable. Abstract As key aquatic organisms, benthos are a reliable indicator of water quality owing to their relatively fixed habitats, limited mobility, and residence at the bottom of the water. This study aimed to analyze benthos' biodiversity and community structure as bioindicators in the waters of the Bengawan Solo estuary that important for fisheries activities conducted by local fishermen community. A descriptive analysis method was employed, involving identifying and analyzing benthos in abundance, biological indexes, and principal component analysis (PCA). The macrobenthos species composition consisted of Gastropoda, Bivalvia, Maxillopoda, Malacostraca, Polychaeta, and Clitellata while meiobenthos comprised Foraminifera, Bivalvia, Gastropoda, and Polychaeta. Macrobenthos abundance was 288 ind./m2, whereas meiobenthos abundance was 16 ind./10 cm2. Both macrobenthos and meiobenthos exhibited a moderate diversity index and a medium evenness index, although evenness values tended to be higher in macrobenthos. The dominance index for both macrobenthos and meiobenthos showed moderate values. PCA analysis revealed that macrobenthos, Bivalvia, Gastropoda, and Clitellata abundance was influenced by brightness and turbidity, Malacostraca and Maxillopoda abundance by salinity, and Polychaeta abundance by dissolved oxygen. In meiobenthos, Gastropoda and Foraminifera abundance was influenced by salinity, whereas Bivalvia and Polychaeta abundance was affected by brightness and turbidity. Abundance and biological index results indicate that the Bengawan Solo estuary is relatively stable.

Quantification of Nitrate Level in Shallow and Deep Groundwater Wells for Drinking, Domestic and Agricultural Uses in Northeastern Arid Regions of Saudi Arabia

Nitrate (NO3−) is a vulnerable natural contaminant that can be found in groundwater. The estimated nitrate concentrations for four categories of wells in the northeastern arid regions of Saudi Arabia—commercial treated water stations for drinking, commercial stations of untreated water for domestic uses, private wells of residences for households, and private wells for agricultural uses—were found to be in the 16–380 mg/L range. Drinking water from all commercial treated water stations has lower nitrate levels, based on the WHO standard of 50 mg/L. In contrast, almost 33% of commercial stations with untreated water (used only for domestic purposes) in the studied areas had higher nitrate levels that were unsuitable for drinking. Approximately half of the private wells of residences and wells for agricultural uses had very high nitrate levels. They can be considered unsuitable for drinking due to excessive levels of nitrates but can be used for domestic and agricultural purposes. Thus, adopting specific strategies to reduce nitrate levels in public wells in the studied areas is crucial. The data obtained in the present study are essential for equipping decision-makers with valuable insights, allowing them to enact appropriate measures, as needed, and uphold community health in the studied regions.

Historic water quality patterns in endemic schistosomiasis regions of southern Africa: Implications for disease vector distribution

Alterations in atmospheric temperature and rainfall have a major influence on the distribution patterns of vector-borne diseases, including schistosomiasis, by changing the optimum habitat of the intermediate hosts (vectors) that transmit these diseases. Water quality degradation and the creation of artificial freshwater habitats may widen or restrict the distribution of disease vectors. Understanding the influence of water quality on ecosystems is essential in determining the environments that vectors thrive in and where potential outbreaks of the disease they carry will occur. This study aims to analyse the changes in various water quality variables between 1977 and 2009 in the Mbombela river systems and how this may have altered the presence of schistosomiasis snail vectors in these areas. Historical water quality data for the Sabie, Kaap, Komati and Crocodile rivers were obtained from the Department of Water and Sanitation monitoring stations and separated into three decades (1977–1987; 1988–1998 and 1999–2009). The Physicochemical Driver Assessment Index (PAI) was used to determine the ecological category of the rivers in each decade. A Principal Component Analysis was also created for the different river systems to identify possible changes in water quality over the 3 decades. According to the PAI, the Sabie River remained in a relatively good state while the Crocodile, Komati and Kaap rivers had a low water quality to begin with and became further degraded over the three decades. The PCAs indicated the Sabie and Crocodile rivers had increased levels of salts, nutrients and pH between 1988-1998 and 1999–2009 while the Kaap River had high salt content and pH between 1977 and 1998 and high nutrients during the decade of 1999–2009. These results indicate that there has been a change in the water quality of Mbombela river systems with notable increases in salt, pH and nutrient levels. As a result, the aquatic biota have likely been negatively affected and this poses severe impacts on the presence and abundance of schistosomiasis vectors as the snails are sensitive to changes in salinity, nutrients and pH.

Operational characteristics of solar-gas combined heating water system with phase change heat storage units for oilfield hot water stations

To achieve the low carbonization heating purpose of oilfield hot water stations, an innovative solar-gas combined heating water system with phase change heat storage (PCHS) units is proposed. The operating characteristics of the combined heating system utilizing PCHS and traditional water heat storage (WHS) are compared. The impact of the phase transition temperature of phase change materials (PCMs) on the operational characteristics is simultaneously investigated. The findings demonstrate that the utilization of PCHS can yield a reduction in gas consumption for the combined heating system by about 7.02 % compared to WHS. Moreover, the combined heating system achieves better energy savings when the phase transition temperature is slightly lower than the heat demand temperature at the load end. The heating demand of gas boilers is reduced by about 75.60 GJ during the summer and autumn when the phase change temperature changes from 80 °C to 62 °C. This study provides theoretical guidance and references for the industrial application of solar heating systems (SHSs) that utilize PCHS units.

The distribution of sediment microplastics assemblages is driven by location and hydrodynamics, not sediment characteristics, in the Gulf of Maine, USA

Microplastics (MP) are found in marine sediments across the globe, but we are just beginning to understand their spatial distribution and assemblages. In this study, we quantified MP in Gulf of Maine, USA sediments. MP were extracted from 20 sediment samples, followed by polymer identification using Raman spectroscopy. We detected 27 polymer types and 1929 MP kg−1 wet sediment, on average. Statistical analyses showed that habitat, hydrodynamics, and station proximity were more important drivers of MP assemblages than land use or sediment characteristics. Stations closer to one another were more similar in their MP assemblages, tidal rivers had higher numbers of unique plastic polymers than open water or embayment stations, and stations closer to shore had higher numbers of MP. There was little evidence of relationships between MP assemblages and land use, sediment texture, total organic carbon, or contaminants.