Water Sites Research Articles

Quantifying the surge-induced response of a floating tidal stream turbine under wave-current flows

Understanding the impact of dynamic effects induced by wave-current conditions on the hydrodynamic performance of a floating horizontal axis tidal turbine (HATT) is crucial toward developing floating tidal turbines to harness tidal energy in deep water sites. The complicated of the wake of a HATT has not yet been fully understood. In this paper, a Computational Fluid Dynamics (CFD) model used to study the performance of a turbine supported by a moored floating platform, due to surge only and in wave-current flows. The CFD model is compared against piled turbine tests, providing an error of 1.36% in power coefficients at the studied TSR = 3.9. It was shown that surge motion caused by even a small wave height or wavelength has a significant effect on the thrust and torque of the rotor. The wave height and period have a remarkable effect on the fluctuation of the hydrodynamic performance due to the induced rotor velocity. The surge motion affects the wake velocity recovery and vortex structure development. For a fuller understanding, future work could explore the negative effects such as induced blade fatigue and platform instability arising from surge motion, as to design cost-efficient turbines, supports and arrangements.

Research on landscape regeneration design of old industrial sites under the concept of sustainable development

By the end of the 20th century, the transformation of industrial economic structure led to the decline of a large number of old industries. The large area of abandoned industrial land left by the city not only hindered the development of the city, but also brought damage to the ecological environment. According to the background of sustainable development theory, around the problems of industrial site wasteland reuse analysis, from many aspects to the industrial site of water, vegetation, soil and further combing ecological restoration, environmental protection, improve the utilization rate of land and the humanistic spirit refining fusion, the industrial wasteland design with natural ecology and context heritage of human natural landscape.

Modelling norovirus dynamics within oysters emphasises potential food safety issues associated with current testing & depuration protocols

Norovirus is a significant global cause of viral gastroenteritis, with raw oyster consumption often linked to such outbreaks due to their filter-feeding in harvest waters. National water quality and depuration/relaying times are often classified using Escherichia coli, a poor proxy for norovirus levels in shellfish. The current norovirus assay is limited to only the digestive tracts of oysters, meaning the total norovirus load of an oyster may differ from reported results. These limitations motivated this work, building upon previous modelling by the authors, and considers the sequestration of norovirus into observed and cryptic (unobservable) compartments within each oyster. Results show that total norovirus levels in shellfish batches exhibit distinct peaks during the early depuration stages, with each peak's magnitude dependent on the proportion of cryptic norovirus. These results are supported by depuration trial data and other studies, where viral levels often exhibit multiphase decays. This work's significant result is that any future norovirus legislation needs to consider not only the harvest site's water classification but also the total viral load present in oysters entering the market. We show that 62 h of depuration should be undertaken before any norovirus testing is conducted on oyster samples, being the time required for cryptic viral loads to have transited into the digestive tracts where they can be detected by current assay, or have exited the oyster.

Tracking contaminants of concern in wet-weather sanitary sewer overflows

Four representative sites in the greater city of Sydney, Australia, were selected for a study of the wet-weather overflow of sanitary (separate to stormwater) sewerage systems. Water samples were collected by autosamplers from up to eight wet weather overflow events over 16 months and from companion receiving water sites. The objective was to identify the risks posed by sewage contaminants to aquatic biota in the receiving waters, to aid in prioritising management actions. Twelve organic contaminants were identified in influents across the four sites under rainfall ingress diluted conditions, with measurements showing that the highest concentrations were restricted to the anti-inflammatory acetaminophen and the diabetes medication metformin. Lesser contaminants included theobromine, ibuprofen, sucralose, and three benzotriazoles (mainly 1-H benzotriazole). An assessment of the toxicity of the identified organic chemicals indicated that none appeared to pose concerns for ecosystem health before wet-weather ingress dilution, and this was even less likely after dilution in the receiving waters. Metal concentrations were low; however, ammonia concentrations in the influent did pose a risk to ecosystem health, although receiving water dilution diminished this risk at four of the five receiving water locations studied.

Quantitative relationships among high-throughput sequencing, cyanobacteria toxigenic genotype abundance and microcystin occurrence in bathing waters

Toxin-producing cyanobacteria pose significant threats to human and animal health if exposed during recreational activities in bathing waters. To better safeguard public health and reduce health risks during the bathing season, an effective monitoring and management strategy is required. Molecular tools used to monitor toxigenic cyanobacteria have been evaluated on the basis of the efficiency and applicability of the method used to (i) establish an early-warning monitoring strategy for EU bathing water sites using both targeted quantitative polymerase chain reaction (qPCR) and non-targeted high-throughput sequencing (HTS) genotype analysis and (ii) to compare the toxigenic potential of cyanobacteria with actual microcystin (MC) occurrence and concentrations. For this purpose, 16 bathing water sites were monitored according to the bathing water directive (BWD) of the European Union (EU) during the bathing season of the summer of 2020 in eastern Austria. The cyanobacterial community composition was analyzed through HTS and qPCR by targeting the microcystin synthetase B gene (mcyB), which indicates MC synthesis within the genera Microcystis and Planktothrix. Within the genus Microcystis, which was identified as the primary MC producer, the mcyB genotypes formed stable subpopulations that increased linearly in correlation with the total Microcystis population. Notably, the HTS cell equivalents assigned to Microcystis and Planktothrix correlated with the corresponding qPCR estimates of genotype abundance, which serves as a confirmation of the suitability of (semi)-quantitative sequencing through HTS. In addition to the elevated trophic state, reduced transparency, increasing water temperatures, as well as cyanobacterial HTS read numbers and Microcystis cell number equivalents per mL estimated through qPCR, were associated with positive MC samples. Therefore, in combination with the monitoring of standard environmental parameters, the use of HTS and qPCR techniques is considered highly useful to ensure the timely identification of health risks to recreational users, as mandated by the BWD.

Optimizing Ocean Bottom Seismometers for Shallow Water Using Shielding and Horizontal Pressure Gradient Data

AbstractWe show large “shields” can significantly reduce horizontal component noise levels for ocean bottom seismometers by shielding the seismic sensors from shaking due to ocean currents. However, at short period (<1 s) some noise from vibration or rocking of the shield under current can partly couple through the ground causing peaks in the noise spectra. Deformation of the seafloor under ocean wave loading (“compliance”) raises noise levels at long period (>5 s) for both vertical and horizontal components at shallow water sites. Pressure gauge data is now routinely used to predict and remove this source of noise on vertical component data. We have developed horizontal pressure gradient (HPG) gauges to measure and remove this source of noise from horizontal component data. The combination of HPG data and shielding enables low noise long period seismic observations at otherwise very noisy shallow seafloor sites.

Variation in Larval Fish Assemblage Dynamics Associated with Harmful Algal Blooms in a Temperate Estuary, South Africa

Eutrophication and concomitant harmful algal blooms (HABs) are on the rise globally and pose a threat to larval stages of fishes that rely on estuarine nursery habitats for growth and survival. The anthropogenically altered low inflow estuary (LIE), Sundays Estuary, South Africa, supports persistent and predictable HABs. This study investigated the effects of HABs on the environmental conditions and larval fish assemblage of this warm temperate nursery area. Sampling took place during the austral spring of 2016 and 2018 at three sites in the mesohaline zone where both larval fish abundance and HABs are known to reach maxima. Physico-chemical and phytoplankton data were collected during the day and night, while larval fishes were sampled after nightfall. Physico-chemical parameters and larval fish assemblages were compared by water column (surface and bottom) and sites within the mesohaline zone, years, and HAB intensity (hypereutrophic ≥ 2781 H. akashiwo cells•mL−1; standard ≥ 205 H. akashiwo cells•mL−1; none < 205 H. akashiwo cells•mL−1). A longer period of consecutive hypereutrophic bloom conditions was recorded during 2018 compared to 2016. Dissolved oxygen concentration was notably higher during hypereutrophic blooms (χ2 = 23.759, df = 2, P < 0.001) and reached a maximum of approximately 21 mg•L−1 during the day and 13 mg•L−1 at night. Density and similarity of estuarine resident larval assemblages were negatively correlated to supersaturated dissolved oxygen concentrations. Greater mean densities of estuarine resident larvae were recorded during hypereutrophic blooms compared to standard blooms and bloom absence and diversity was lower during 2018 when hypereutrophic bloom conditions were more persistent. These changes may have major implications for successful early development of fishes that rely on the Sundays Estuary and similar LIEs as a nursery.

New Faunal Data for Black Flies (Diptera: Simuliidae), with the Evidence of COI Sequences, from Mediterranean Region of Türkiye

The present study provides faunal data for Turkish Black flies (Simuliidae, Diptera) from the Central and Western Mediterranean Region in Türkiye. Among the specimens collected from 221 different running water sites, 17 species in 3 genera and 5 subgenera were identified. Two species, Simulium (Nevermannia) ibleum (Rivosecchi 1966) and Simulium (Nevermannia) brevidens (Rubtsov 1956), were recorded for the first time from Türkiye, and 5 additional species were reported from the study area for the first time. The morphological identifications were tested by phylogenetic analyzes using mitochondrial cytochrome oxidase I (COI) barcode sequences. The COI analysis results overlapped with the morphotaxonomic identification results for eight of the 15 species. The first genetic data of 4 species (for World) and 5 species (from Türkiye) were stored in GenBank (NCBI).

Seasonal variation of Ichthyofaunal diversity and it’s relation with substratum in the River Changa, West Bengal, India

Aim: A survey was conducted at four sampling sites of the River Changa to study the fish diversity in relation to river substratum. The aim of the study was to prepare a check list of ichthyofaunal diversity and their habitat preference guild in relation to sediment type. Methodology: Ichthyofauna was collected from four selected stations at monthly interval with the help of fishermen using gill net and cast net. For the analysis of the riverine substratum, sediment samples were collected from six square inches area at the sampling sites of the river by grab sampling method. The composition of stones, pebbles, sand and mud were evaluated from the sample. Results: A total of 64 fish species belonging to 6 families and 18 orders were recorded. Among which 33 were cold water fishes, 31 were warm water fishes, 28 were rheophilic and 24 were eurytopic fishes. Site 1 and 2 were dominated by rheophilic and cold water fishes and Site 4 was rich in eurytopic and warm water fishes. Cypriniformes was the most dominant order with 42 fish species. River sediment of Site 1, 2 and 3 were dominated by stones, pebbles and sand, while sediments collected from Site 4 was dominated by sand and mud. Cold water and rheophilic fishes were positively influenced by stones and pebbles. Eurytopic and warm water fishes were positively influenced by sand and mud. Interpretation: Cold water and rheophilic fishes were abundant at upstream of the river and eurytopic and warm water fishes were abundant at downstream of the river. Abundance and distribution of fish species depends on the river substratum. Key words: Ichthyofaunal diversity, Rheophilic, River Changa, River substratum

상하수처리시스템용 현장제어반의 복합이상감시 기술 개발

On the site of water and sewage treatment facilities, in order to control and monitor not only distribution installed control equipment but also power equipment and lighting equipment, on-site control panels are installed in addition to a central monitoring and control system, to form an automatic control system. In particular, in order to comprehensively manage control power failures inside the on-site control panels, the prototype under development has additional features: a DC power abnormality monitoring device that monitors control power overload and arc discharge was developed, installed and applied to the on-site control panel, and an arc sensor, an infrared sensor, and a vibration sensor which are widely used across the industry were also installed to diagnose the integrity of the insulation inside the panel.

BREEDING ECOLOGY, NESTING HABITAT AND THREATS TO A BLACK-AND-CHESTNUT EAGLE SPIZAETUS ISIDORI POPULATION IN THE MONTANE FORESTS OF CENTRAL PERU

The Black-and-chestnut Eagle Spizaetus isidori is an endangered and little-known top predator of South American montane forests. To better understand the breeding ecology and threats of this eagle, we studied several pairs between 2017 and 2022 in the central Andes of Peru. We recorded 62 adults, one immature, and 36 juveniles in 36 territories. These territories were in mountainous areas (altitudinal range 690–3,810 m a.s.l.), widely covered by montane forests (43.8–99.7% cover), and secondarily by open land (0.3–56.2% cover), far from urban settlements (1.3–27.1 km). Nesting sites (N = 15) were at medium altitudes (1,330–2,330 m a.s.l.) in steep hillsides or ravines (15–55°), having no preferential cardinal orientation, and relatively close to permanent water courses (20–800 m), open areas (30–930 m) and sites with human activity (120–2,200 m). Nests (N = 15) were placed at the top of tall (28–40 m) and thick-stemmed (DBH range 0.53–1.52 m) emergent trees of nine genera, with Ficus and Juglans being the most used. Incubation and brood-rearing occurred during the dry season (Mar–Nov). The wooded slopes where the eagles nested are being replaced by crops and livestock pastures, causing an estimated loss of 218.2 km2 of forest cover in our study area (5,056 km2) during the last 20 years. We detected human persecution in 55.5% of the territories, resulting in 26 juveniles, four adults, two immatures, and nine unaged eagles killed. Preventing the local extinctions of these eagles will require long-term population monitoring, improving knowledge of its ecology, mitigation of human-eagle conflict, development of education programs, and strengthening of land use inspection.

Reduction of human fecal markers and enteric viruses in Sydney estuarine waters receiving wet weather overflows

The current microbial source tracking (MST) study tracked the reduction of the culturable fecal indicator bacteria enterococci, four human fecal markers (Bacteroides HF183, Lachnospiraceae Lachno3, cross-assembly phage (CrAssphage) and pepper mild mottle virus (PMMoV)) along with four enteric viruses - human adenovirus 40/41 (HAdV 40/41), enterovirus (EV), human norovirus GI (HNoV GI) and GII (HNoV GII) post wet weather overflows (WWOs) at two estuarine water sites from two depths under separate six-day sampling campaigns over seven and 12 days in Sydney, NSW, Australia. Neither HNoV GI nor GII was detected, while 13.9 % (10/72) of estuarine water samples had detections of EV. Quantifiable concentrations (0.64 to 2.00 log10 gene copies (GC)/100 mL) for HAdV 40/41 were returned from 65.2 % (47/72) of samples collected across the two sites and two depths with 30 quantifications recorded in the surface layer samples. In contrast the presence of HF183, Lachno3, CrAssphage, and PMMoV markers was observed in all 36 (100 %) estuarine water samples collected from the surface layer from both sites. Detection frequencies of these markers were slightly lower at 1 m above the bottom surface. The concentrations of the human fecal markers were compared to established gastrointestinal (GI) risk benchmarks. The concentrations of HF183, Lachno3 and CrAssphage marker only exceeded the GI risk benchmark until day 3, while concentrations of PMMoV marker were indicative of exceedance of the GI risk benchmark on day 7 post WWOs that was much longer than indicated by culturable enterococci concentrations that were within this GI risk benchmark by day 2 and day 4 for the two sites, respectively.

Microplastics Records from the Southern Ocean Sediments

ABSTRACT The study records the extent of microplastics distribution in the surficial sediments of the Southern Ocean. This represents the first study of microplastics in the sediments of Prydz Bay, Southern Ocean. Prydz Bay is the largest embayment located in the Indian Ocean Sector of the Southern Ocean and receives sediments supplied by the Lambert Glacier/Amery Ice Shelf, draining approximately 10% of the total ice volume of Antarctica. It is an important site of circumpolar deep water (CDW) and Antarctic bottom water (AABW) formation. This study focuses on the distribution of microplastics in the sediments of the Prydz Bay, Southern Ocean with special reference to the ecological risk factor of these microplastics. The type distribution of microplastics revealed percent content as bead > fiber > fragment. Ecological risk factors (CF and PLI) of microplastics in sediment samples revealed a minor to major risk of these pollutants in the analyzed environment. Statistical analyses such as principal component analysis (PCA), ANOVA, Tukey's HSD test, and correlation analysis were performed to highlight the interrelationship of MPN with CF, PLI, pH, TOC, and sediment texture. The levels of microplastic pollution in the Prydz Bay are significant on a local scale, particularly around research stations. This report underlines the immediacy of microplastic pollution management in the Southern Ocean to maintain the serenity of this pristine marine habitat. So further research on the information of microplastics policy discussions to develop appropriate management responses.

Site‐specific space use and resource selection by Black Vultures (Coragyps atratus) in the southeastern USA

North American populations of Black Vultures Coragyps atratus have increased and expanded their distribution in the southern and eastern USA. In conjunction with these patterns has been a rise in human–vulture conflicts. To improve our understanding of space use patterns and better inform management, we evaluated the movements of Black Vultures (n = 23) in the southeastern USA using a long‐term GPS tracking database. Our specific objectives were to: (1) quantify home‐range sizes in relation to season and geographical study location and (2) examine within‐home‐range resource selection to identify landscape and anthropogenic factors influencing roost and diurnal space use. Home‐range sizes did not significantly differ between breeding and non‐breeding seasons. However, there were differences across geographical study locations, with the largest home‐ranges located in Florida. Similarly, there was limited seasonal variation in resource selection; however, use of anthropogenic features did vary by geographical study location. Overall Black Vultures avoided homogeneous landscapes regardless of season or activity and exhibited a strong selection for areas with increased landscape richness. Increased landscape richness, unlike homogeneous habitat, provides a diversity of resources for Black Vultures in a localized area, such as food, water, roosting and perch sites, and the creation of energy‐efficient flight opportunities. Contrasting with natural landscape feature selection, selection of anthropogenic features, such as landfill proximity and road density, was highly variable across individuals and study location. The high level of variation in selection for anthropogenic features provides further evidence of the propensity of Black Vultures to be flexible and opportunistic. The findings of this study stress the importance of using site‐specific studies effectively to understand and manage local vulture populations and mitigate associated human–vulture conflicts. Wildlife managers should exercise caution when implementing vulture management actions based on inferences from telemetry studies conducted in other geographical areas.

Seasonal fluctuations and diversity of Ingoldian mycobiota in two water bodies receiving different effluents at Assiut Governorate (Upper Egypt)

In the current study, fifty-eight Ingoldain fungal species assignable to forty-one genera were recovered from two water bodies receiving the treated sewage and the effluents of oils and soaps factory at Assiut Governorate (Upper Egypt), of which Anguillospora, Amniculicola, Flagellospora, and Mycocentrospora were the most prevalent genera. The most widespread identified species were Anguillospora furtive, Amniculicola longissima and Flagellospora fusarioides. Forty-three species were identified for the first time in Egypt. The most Ingoldain taxa were estimated for El-Zinnar canal, with the highest recorded taxa in winter. Whereas, the highest dominance of Ingoldian fungi was estimated for the El-Ibrahimia canal. The highest Simpson and Shannon diversity indexes were estimated for El-Zinnar canal samples recording 0.9683 and 3.741, respectively. The poorest water sites with Ingoldian fungi were those exposed directly to either treated sewage or industrial effluents, with which relatively higher values of water conductivity, cations and anions. Water temperature was the main abiotic factor driving the seasonal occurrence of Ingoldian fungi. It is interesting to isolate some Ingoldian fungal species from the stressful water sites receiving the effluents which provide valuable insights regarding their adaptation, predictive and putative role as bioindicators and their potentiality in pollutants degradation, organic decomposition, and transformation of xenobiotic compounds.

Microplastics in water, feed and tissues of European seabass reared in a recirculation aquaculture system (RAS)

Plastic particles (PLs) are ubiquitous in aquatic ecosystems, and aquaculture production is susceptible to contamination from external or endogenous sources. This study investigated PL presence in water, fish feed and body sites of 55 European seabass produced in a recirculating aquaculture system (RAS). Fish morphometric parameters and health status biomarkers were determined. A total of 372 PLs were recovered from water (37.2 PL/L), 118 PLs from feed (3.9 PL/g), and 422 from seabass (0.7 PL/g fish; all body sites analysed). All 55 specimens had PLs in at least two of the four body sites analysed. Concentrations were higher in the gastrointestinal tract (GIT; 1.0 PL/g) and gills (0.8 PL/g) than in the liver (0.8 PL/g) and muscle (0.4 PL/g). PL concentration in GIT was significantly higher than in muscle. Black, blue, and transparent fibres made of man-made cellulose/rayon and polyethylene terephthalate were the most common PLs in water and seabass, while black fragments of phenoxy resin were the most common in feed. The levels of polymers linked to RAS components (polyethylene, polypropylene, and polyvinyl chloride) were low, suggesting a limited contribution to the overall PL levels found in water and/or fish. The mean PL size recovered from GIT (930 μm) and gills (1047 μm) was significantly larger than those found in the liver (647 μm) and dorsal muscle (425 μm). Considering all body sites, PLs bioconcentrated in seabass (BCFFish >1), but their bioaccumulation did not occur (BAFFish <1). No significant differences were observed in oxidative stress biomarkers between fish with low (<7) and high (≥7) PL numbers. These findings suggest that fish produced in RAS are mainly exposed to MPs through water and feed. Further monitoring under commercial conditions and risk assessment are warranted to identify potential threats to fish and human health and define mitigating measures.

Water as a Strategic Resource in the Western Samaria Region – The Unique Case of Deir Sam’an: The Water System that Has Been Operating for 1,500 Years

ABSTRACT Maintaining a proper water supply is a subject of constant concern in arid and semi-arid regions of the world, including the Mediterranean Basin and, more specifically, Western Samaria. Solutions such as cisterns, reservoirs, water tunnels, and springs were developed and perfected throughout history to enable a regular supply of water to the local population. The case of Deir Sam’an is particularly interesting, as it seems the site's water storage capability is much larger than needed during its activity in the Roman-Byzantine period. At the site, located in Western Samaria, several Roman-Byzantine water systems were found including reservoirs and large cisterns. Its main water system, which is still operating, enables a reliable estimate of the available water amount to the site residents in antiquity. In the winter of 2020-2021, the daily precipitation volume and the annual rise in pool levels were measured and compared with the water amount at the end of the summer. The results validated that the water storage capability far exceeds the estimated demand of Deir Sam’an's population. This paper suggests that a large amount of water was utilized by the Byzantine Empire as a strategic management tool of settlement in the area to attract its preferred population to the Western Samaria region.

Content level and risk assessment of phthalate esters in surface water of Bosten Lake, China.

Bosten Lake is the main fishing and grazing area in Xinjiang. The pollution of phthalate esters (PAEs) in water has attracted much attention, but limited research has been conducted on PAEs in Bosten Lake. The distribution of PAEs in fifteen sampling sites of surface water in the dry and flood seasons were investigated to explore the content level of PAEs in Bosten Lake, and the risk was evaluated. Seventeen PAEs were detected by GC-MS after liquid-liquid and solid-phase purification. Results showed that the content of ∑PAEs in the water during dry and flood seasons is ND-26.226μg/L and ND-7.179μg/L. The content of PAEs in the water of Bosten Lake is at a medium level. DBP and DIBP are the main PAEs. The content of PAEs is related to the physicochemical properties of water, and the physicochemical properties of water in dry season have a more serious impact on PAEs. PAEs in water mainly come from domestic pollution and chemical production. The results of health risk assessment indicate that PAEs in water do not pose a carcinogenic risk or a non carcinogenic risk to human, which can meet the conditions of Bosten Lake as a fishing ground and livestock base, but the pollution of PAEs cannot be ignored.

Environmental DNA clarifies impacts of combined sewer overflows on the bacteriology of an urban river and resulting risks to public health

There is no reference of microbiological water quality in the European Union's Water Framework Directive, adapted into English law, and consequently microbial water quality is not routinely monitored in English rivers, except for two recently designated bathing water sites. To address this knowledge gap, we developed an innovative monitoring approach for quantitative assessment of combined sewer overflow (CSO) impacts on the bacteriology of receiving rivers. Our approach combines conventional and environmental DNA (eDNA) based methods to generate multiple lines of evidence for assessing risks to public health. We demonstrated this approach by investigating spatiotemporal variation in the bacteriology of the Ouseburn in northeast England for different weather conditions in the summer and early autumn of the year 2021 across eight sampling locations that comprised rural, urban, and recreational land use settings. We characterized pollution source attributes by collecting sewage from treatment works and CSO discharge at the peak of a storm event. CSO discharge was characterized by log10 values per 100 mL (average ± stdev) of 5.12 ± 0.03 and 4.90 ± 0.03 for faecal coliforms and faecal streptococci, and 6.00 ± 0.11 and 7.78 ± 0.04 for rodA and HF183 genetic markers, for E. coli and human host associated Bacteroides, respectively, indicating about 5 % sewage content. SourceTracker analysis of sequencing data attributed 72–77 % of bacteria in the downstream section of the river during a storm event to CSO discharge sources, versus only 4–6 % to rural upstream sources. Data from sixteen summer sampling events in a public park exceeded various guideline values for recreational water quality. Quantitative microbial risk assessment (QMRA) predicted a median and 95th percentile risk of 0.03 and 0.39, respectively, of contracting a bacterial gastrointestinal disease when wading and splashing around in the Ouseburn. We show clearly why microbial water quality should be monitored where rivers flow through public parks, irrespective of their bathing water designation.

Salinity and total dissolved solids measurements for natural waters: An overview and a new salinity method based on specific conductance and water type

The total concentration of dissolved constituents in water is routinely quantified by measurements of salinity or total dissolved solids (TDS). However, salinity and TDS are operationally defined by their analytical methods and are not equivalent for most waters. Furthermore, multiple methods are available to determine salinity and TDS, and these methods have inherent differences. TDS is defined as the mass of anhydrous residue remaining in a sample vessel after evaporation and subsequent oven drying at a defined temperature. Salinity is a measure of the mass of dissolved salts in a given mass of solution. In addition, there are approaches that quantify the total solute (TS) concentration, including gases. The purpose of this study is to develop a proxy method using specific conductance and major-ion water type to reliably predict salinity, TDS, and/or TS. Thus, we compared several methods to calculate salinity, TDS, and TS for 6391 surface water samples and conclude the following: TDS measurements are best suited for studies of anhydrous residue (e.g., evaporites); salinity determined by summing the speciated ion concentrations, termed S∑spec, is the most comprehensive method to represent the concentration of dissolved constituents in natural waters; and TS determinations are useful if dissolved CO2 and other gases are of interest. Thus, we utilized S∑spec to compare differences between the various salinity, TDS, and TS methods, and to develop a new proxy method to predict salinity based on specific conductance (SC) and major ion water type, termed SSC_WT. For the surface waters used in this study, the median difference between TDS and S∑Spec was between −19% and −24%, depending on the method. The median difference between SSC_WT and S∑Spec was −2.4% for the samples in this study. The SSC_WT approach is cost effective, rapid, and capable of providing reliable real-time salinity determinations at surface water sites where SC data are available and water type is known.