High Turbidity Values Research Articles

Application of a Novel Disposable Flow Cell for Spectroscopic Bioprocess Monitoring

The evaluation of the analytical capabilities of a novel disposable flow cell for spectroscopic bioprocess monitoring is presented. The flow cell is presterilized and can be connected to any kind of bioreactor by weldable tube connections. It is clamped into a reusable holder, which is equipped with SMA-terminated optical fibers or an integrated light source and detection unit. This modular construction enables spectroscopic techniques like UV-Vis spectroscopy or turbidity measurements by scattered light for modern disposable bioreactors. A NIR scattering module was used for biomass monitoring in different cultivations. A high-cell-density fed-batch cultivation with Komagataella phaffii and a continuous perfusion cultivation with a CHO DG44 cell line were conducted. A high correlation between the sensor signal and biomass or viable cell count was observed. Furthermore, the sensor shows high sensitivity during low turbidity states, as well as a high dynamic range to monitor high turbidity values without saturation effects. In addition to upstream processing, the sensor system was used to monitor the purification process of a monoclonal antibody. The absorption module enables simple and cost-efficient monitoring of downstream processing and quality control measurements. Recorded absorption spectra can be used for antibody aggregate detection, due to an increase in overall optical density.

Combined Effects of Local and Regional Drivers on Oyster Spat Density and Growth in Eastern Australia

Up to 85% of shellfish reefs have been lost worldwide, resulting in declining ecosystem services, and increasing restoration demand. However, more information regarding the conditions which maximise oyster settlement and growth is required to optimise restoration. We deployed oyster settlement tiles at 21 intertidal sites throughout Moreton Bay, Australia; a region where > 96% of rock oyster reefs are lost and demand for restoration is high. We quantified effects of variables describing the spatial (from GIS), local habitat (using quadrats and water quality measures), and oyster predator (using underwater videography) characteristics of sites on oyster density and size on tiles. Oyster density was highest at sites with intermediate predator abundance and temperature, highest nearby invertebrate cover, and low and high values of turbidity and nearby rock and algae cover. Conversely, oyster size was highest at sites with intermediate predator density, higher fish species richness and turbidity, and lowest temperatures. Together, this showed that optimal restoration requires sites with 22 to 23 °C average water temperatures, between 10 and 15 oyster predators, and either low (< 2 NTU) or high (> 6 NTU) turbidity levels. Notably, we observed multiple peaks for several variables, suggesting the potential presence of multiple cryptic oyster species on settlement tiles. We found that oysters shared preferred environmental conditions with polychaetes, coralline algae, and tunicates, and were more prevalent and abundant at sites with lower turf algae, barnacle, and mussel cover. Identifying environmental variables influencing oyster population distribution, settlement, and growth can guide the selection and approach of oyster restoration sites.

Three-Dimensional Numerical Modeling of Ground Ice Ablation in a Retrogressive Thaw Slump and Its Hydrological Ecosystem Response on the Qinghai-Tibet Plateau, China

Retrogressive thaw slumps (RTSs), which frequently occur in permafrost regions of the Qinghai-Tibet Plateau (QTP), China, can cause significant damage to the local surface, resulting in material losses and posing a threat to infrastructure and ecosystems in the region. However, quantitative assessment of ground ice ablation and hydrological ecosystem response was limited due to a lack of understanding of the complex hydro-thermal process during RTS development. In this study, we developed a three-dimensional hydro-thermal coupled numerical model of a RTS in the permafrost terrain at the Beilu River Basin of the QTP, including ice–water phase transitions, heat exchange, mass transport, and the parameterized exchange of heat between the active layer and air. Based on the calibrated hydro-thermal model and combined with the electrical resistivity tomography survey and sample analysis results, a method for estimating the melting of ground ice was proposed. Simulation results indicate that the model effectively reflects the factual hydro-thermal regime of the RTS and can evaluate the ground ice ablation and total suspended sediment variation, represented by turbidity. Between 2011 and 2021, the maximum simulated ground ice ablation was in 2016 within the slump region, amounting to a total of 492 m3, and it induced the reciprocal evolution, especially in the headwall of the RTS. High ponding depression water turbidity values of 28 and 49 occurred in the thawing season in 2021. The simulated ground ice ablation and turbidity events were highly correlated with climatic warming and wetting. The results offer a valuable approach to assessing the effects of RTS on infrastructure and the environment, especially in the context of a changing climate.

Water and sediment pollution of intensively used surface waters during a drought period — a case study in Central Northern Namibia

Semiarid regions are often affected by water scarcity and poor water quality. Seasonal changes in precipitation and drought events increase the pressure of use on water bodies and their pollution. In Central Northern Namibia, a high seasonal intra- and inter-annual variability of precipitation caused a 5-year lasting drought period. In the semiarid region, ephemeral channels and water pans represent the main water source, besides the institutionalized water supply. No systematic analysis of its quality has been conducted so far. The states of the surface waters at the end of the dry season in 2017 and the end of the rainy seasons in 2018 and 2019 were characterized by the analysis of physical–chemical parameters, focusing on usability. The first results show coarse contamination of the waters, which results in high turbidity values. Salt concentrations, such as Ca2+ and Na+, greatly increased due to evaporation. Al is present in high concentrations in solid and liquid phases, which indicates direct anthropogenic pollution. Spatial differences are evident in the study area and based on the precipitation gradient, land use, and population density. The waters cannot be used as drinking water without prior treatment.

Assessing the ecological health of River Ringim, Northwestern, Nigeria using macroinvertebrate-based Chanchaga Multimetric Index

ABSTRACT The ecological health of River Ringim, Jigawa State, northwestern Nigeria was assessed between November 2018 and March 2019. Key physico-chemical variables alongside macroinvertebrates assemblage were used to achieve the aim of the study. The result of the physico-chemical variables showed that the four stations sampled were relatively perturbed judging from the high values of turbidity, nitrate, phosphate, BOD, TDS, and EC. Twelve (12) taxa and 365 individuals of macroinvertebrates were recorded in the entire study period of five months, confirming the deteriorating state of the river system. Hemiptera which was represented by 126 individuals was the most preponderant macroinvertebrate Order, followed by Coleoptera with 100 individuals. The least represented Order was Crustacea with only five individuals. The result of the diversity indices conducted showed that the Margalef index (1.32), Simpson diversity (0.76), and Shannon-Weiner index (1.59) were highest in Station 1. The results were used to check the implementation of the Chanchaga multimetric index and it showed that that the four stations of River Ringim were of poor water quality with a corresponding D ecological category. This further, confirmed the deteriorating state of the four stations sampled. We recommend that macroinvertebrate-based multimetric index (MMI) be developed for the river using a macroinvertebrates particular to the river instead of using the results in this study in checking the implementation of MMI developed for another river. This will ascertain the actual level of degradation River Ringim is undergoing due to the numerous human disturbances within the river catchments.

A storm driven turbidity maximum in a microtidal estuary

Many macro- and mesotidal estuaries are characterized by Turbidity Maxima Zones (TMZs), regions with suspended solid concentrations that are much higher than those found throughout the rest of the estuary. Such regions are located near the upriver limit of salt intrusion and their position and extent are modulated and driven by tidal oscillations, especially in estuaries where tidal forcing is large. Hence, pronounced TMZs are not typically expected in micro-tidal estuaries. Field experiments were carried out in the microtidal estuary of the Misa River (northeast coast of Italy) with the aim to analyze riverine-coastal ocean interactions during different climatic conditions, freshwater discharge and tidal forcing. The goal was also that of identifying factors and episodic conditions that could lead to the evolution of ephemeral TMZs in this microtidal estuarine system. Observational results, combined to a flocculation model suite, describe the hydrodynamics, morphological bed evolution, water chemistry and floc dynamics within the estuary during wintertime quiescent and stormy periods. Pronounced TMZs with different location and extent were observed during two storms with different intensities, when enhanced freshwater discharge, wave action and tidal oscillation generated significant stratification of the lower estuarine water column. Higher turbidity values were observed throughout the TMZ during the smaller/weaker storm, while stronger surface mixing during the stronger storm led to greater dispersion of the (re-)suspended particulate load throughout the upper water column, providing a less pronounced TMZ along the bed of the lower estuary. Observations in the Misa River, potentially valid for other microtidal estuaries, show that: 1) episodic storm conditions that significantly increase freshwater discharge can lead to the evolution of an ephemeral TMZ that is modulated, but not controlled, by tidal oscillations and surface mixing conditions; 2) ephemeral TMZ localization, intensity, and extent during episodic storm events is a function of storm intensity; 3) moderately enhanced freshwater flow during an episodic storm event promotes a high degree of stratification, allowing for the formation of large flocs with great settling rates, leading to a pronounced TMZ forming downriver of the landward limit of seawater intrusion; whereas higher freshwater flows during stronger storm events lead to less stratification, greater bottom turbulence and potential TMZ suppression near the riverbed, with shear conditions promoting smaller flocs with lower settling and a greater potential for suspended particulate export from the lower estuary to coastal waters.

Assessment of the water quality of the Niger River in Bamako, Mali, based on the Water Quality Index

Abstract The Niger River, threatened by human activities, is the main drinking water source for the population of Bamako city. This study assesses the trend of Niger River pollution in Bamako using the Water Quality Index (WQI). Fourteen parameters, namely Turbidity, Potential of Hydrogen (pH), Electrical Conductivity, Dissolved Oxygen, Total Dissolved Solids, Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Nitrate, Nitrite, Ammonium, Phosphate, Sulphate, Chloride and Copper, were employed to characterise the Niger River water quality during the period from 2016 to 2020. Parameters were measured at 15 sampling locations. High values of Turbidity, pH and high concentrations of BOD5, COD, Nitrite, Ammonium and Phosphates were recorded. The results showed that the Niger River water quality was good for 4 months and poor for 5 months during the dry season in a low flow period. Moreover, the water quality was poor during the 3 months of the wet season in the high flow period. The calculated WQI average values ranged from 75 to 100, indicating very poor water quality from upstream to downstream of Bamako city. Therefore, the Niger River water is polluted and cannot be used for drinking or industrial uses without any treatment.

Efeito da qualidade da água na fauna macrobentônica no rio Achenkovil, Southern-West Ghats, Kerala, Índia

Abstract Aim The present study investigated the influence of environmental variables on macrobenthic fauna in the Achenkovil River, Southern Western Ghats, Kerala. The knowledge of aquatic ecosystems in many remote areas is very scanty and no one has yet made an attempt to study the macrobenthic fauna of Achenkovil river. Since, macrobenthos play an important role in the benthic community structure a better knowledge of their ecology and distributional patterns in remote freshwater ecosystems would be of great interest for a better understanding of their functioning. Methods A bimonthly sampling was conducted from February 2019 to January 2020. Water samples for physicochemical analysis were carried to the laboratory in clean polyethylene bottles. The macrobenthic fauna was collected using Van Veen grab (0.025m2). Multivariate statistical technique such as Principal Component Analysis was used to monitor the variation in environmental parameters. The diversity of macrobenthic fauna was studied using Simpson_1-D, Shannon_H, Evenness_e^H/S, and Margalef’s indices. We analyzed the relationship between environmental variables and macrobenthic fauna, using Canonical Correlation Analysis and Pearson correlation. Results A total of 3563 individuals belonging to 9 orders, 32 families, 32 genera, and 32 species were identified. The most dominant order was Ephemeroptera followed by Coleoptera and Trichoptera and the least dominant was Zygoptera. The maximum number of macrobenthic fauna was observed in station 1(S1), (1461 Ind/m2) and the least in station 9 (S9), (37 Ind/m2). Station 1 (S1) is a pristine forest area, so this area is considered the reference site. The macrobenthic fauna in the pristine headwater forests (S1) was much more diverse than in the river mouth (S9) which is a highly impacted region. This region is facing various kinds of anthropogenic stress resulting in pollution and deterioration of water quality. The macrobenthic community structure in the Achenkovil River was significantly associated to the variations in water quality due to various natural as well as anthropogenic stresses. Conclusions It can be concluded that Ephemeroptera, Coleoptera, and Trichoptera were the most dominant groups in the undisturbed habitats in the river during the study period. The predominance of Chironomidae species, especially from the Chironomus genus in the midstream and downstream segments of the river is possibly due to their ability to adapt to various environmental conditions or habitats and their tolerance to the low oxygen content in anoxic conditions of the bottom sediment. The lowest abundance of macrobenthos at all the studied stations was observed at station 9 (S9) during dry seasons. S9 is a highly impacted region, characterized by high temperature, turbidity, TDS, pH, conductivity, nitrate, and phosphate values. For this reason, anthropogenic stress and changing environmental conditions are the main factors affecting the distribution of the macrobenthic fauna of the Achenkovil River basin, Kerala.

Restrictions in water treatment by conventional processes (coagulation, flocculation, and sand-filtration) following scenarios of dam failure

Dam failure events can result in a high suspended solids concentration in surface waters. To understand the impact of high suspended solids concentration on the treatment process of water treatment plants, this study investigated coagulation-flocculation stages using different coagulants (ferric chloride and a polymeric coagulant – CAT-FLOC 8799 Plus) and solids concentrations (2000–46,000 mg/L), and how they impacted on the mean diameter (d50), density (ρs), and settling velocity (vs) of the agglomerates formed. After the sedimentation process, the turbidity values varied between 201–26 NTU when FeCl3 was used as a coagulant, and 36–11 NTU when using the organic coagulant. The study reinforces the effect of particle diameter on sedimentation velocity, which is lower for cases involving smaller average diameters. Even so, solids removal was high regardless of the initial conditions and characteristics of the agglomerated particles, starting early in flocculators with removals >80 %. The results point to the need for frequent maintenance of these units to remove the sludge settled, which could compromise the operation of water treatment plants. In this sense, two alternatives were proposed as pre- and post-treatment. Under high total solids concentration (>20,000 mg/L), pre-treatment with thickeners becomes mandatory, and ultrafiltration comes as an additional barrier that will prevent high turbidity values in drinking water. In this study, the use of ultrafiltration membranes in partial or total replacement of sand filters showed stable performance (permeate flow: 130–136 L/m2h) with no tendency to fouling and guaranteeing a residual turbidity value <0.3 NTU. Future studies should prove the technical and operational feasibility of the strategies proposed, which until then showed promising results to guarantee the operation of water treatment plants in adverse scenarios.

Source Apportionment of Chemical Elements and Their Geochemical Baseline Values in Surface Water of the Parauapebas River Basin, Southeast Amazon, Brazil

The present work aims to evaluate the chemical quality and establish the geochemical baseline values of elements in the surface waters of the Parauapebas River basin (PRB), which is one of the major subbasins in the Itacaiúnas River watershed (IRW) located in the Brazilian Amazon. A total of 327 surface water samples were collected during the rainy and dry seasons in 2017. Results indicate that waters are slightly acidic to alkaline (pH 6 to 8), and there was a strong influence of the seasonal variation on water quality, with higher values of turbidity, Fe, Al, Mn, TDS, etc. in the rainy season. Two geochemical baseline types for the PRB were defined, i.e., ‘conservative baseline’ (CB), represented by the cumulative frequency curve, and the ‘environmental baseline’ (EB), comprising the sum of natural and diffuse anthropogenic contributions, represented by the 98th percentile. Except Fe, Mn and Al, the CB and EB values of various trace elements (Ba, Co, Cr, Cu, Ni, Rb, Sn, Sr, Ti, V and Zn) were lower than the recommended limits of CONAMA 357/05—class 2. The principal component analysis (PCA) identified the major geochemical association (Al-Ti-Cu-Cr-Ni-V), which is an imprint of the local geological setting. Ni and Cr showed enrichment at sites where mafic and ultramafic rocks are concentrated, while Cu concentration is mainly associated with the north and south mineralization belts. High concentrations of Fe and Mn are characteristic of the waters of this region and this is mostly influenced by specific land use activities and intense weathering/erosion of catchment materials. At the upper Parauapebas, anthropogenic contributions associated with soil use and occupation were also important along with the geogenic effects. The obtained results regarding sources of contaminants in some microbasins can be taken as a starting point for future studies on the environmental quality of the region’s water resources.

Bioindicadores de calidad hídrica con diferente cobertura ribereña en la microcuenca Guapara, Ecuador

Agricultural activities produce changes in the margins of the stream banks, causing disturbances in water quality, and in the assemblage of aquatic insect communities. The objective of this research is to evaluate the changes in the structure and composition of the aquatic macroinvertebrate community, and physicochemical variables in relation to the land use of the Guapara river, Cotopaxi province, Ecuador. Samplings were conducted during the rainy season (December to February 2018-2019) in three streams with different riparian cover: agricultural, native forest, and forest plantations, where samples of aquatic insects and physicochemical parameters were collected in situ. A total of 461 aquatic insects corresponding to 7 orders and 25 families were collected. In general, the highest abundance in order and family was presented by Ephemeroptera with 34 %, and Leptophlebiidae with 21 % respectively. According to the Ephemeroptera, Plecoptera Trichoptera (EPT) index, the highest ecological condition was found in streams with native forest cover, and forest plantations respectively, and decreased in the stream with agricultural cover; while BMWP-Cr indicated water contamination in the three streams. Hydrobiosidae (Trichoptera) were associated with high turbidity values; while Gerridae (Hemiptera) were associated with high dissolved oxygen concentrations; in addition, Ptilodactylidae (Coleoptera) preferred the Q1-CA, and Q3-CF conditions, while Leptophlebiidae (Ephemeroptera) were associated with the stream of native forest. A negative influence of agricultural activity on the physicochemical parameters of the water and on the structure of the aquatic insect community assemblage was evidenced.

Water Turbidity and Suspended Particulate Matter Concentration at Dredged Material Dumping Sites in the Southern Baltic.

Dredged material dumping is an activity that causes some of the greatest changes in coastal waters. It results in the need to regularly monitor the properties of seawater related to water quality. In this study, we present the first wide-ranging attempt to correlate seawater turbidity and suspended particulate matter (SPM) concentrations within dumping sites and adjacent waters on the basis of in situ measurements. In the years 2019–2020, we examined four dumping sites, namely Darłowo, Gdynia, Gdańsk, and DCT, located in Polish coastal waters of the Baltic Sea, in the course of four measurement campaigns conducted in the spring, summer, autumn, and winter. The measurements were conducted using a turbidity sensor to determine the turbidity, in formazin turbidity units (FTU), a spectrophotometer to determine the concentrations of nutrients (total phosphorus (P-tot), phosphate phosphorus (P-PO4−3), total nitrogen (N-tot), ammonium nitrogen (N-NH4+), and nitrate nitrogen (N-NO3−)), as well as glass microfiber filters to determine the concentrations of SPM. The analysis of the relationship between the turbidity and SPM within the dumping sites in comparison to reference points showed that the dumping sites are very complex waters and that the issue must be approached locally. The highest turbidity values were registered in the spring, and they correlated linearly with the SPM concentrations (R2 = 0.69). Moreover, we performed a statistical cluster analysis to illustrate the similarities between sampling points in the four dumpsites based on nutrient concentrations. We conclude that the influence of the dumping sites on the local bio-optical and chemical properties significantly exceeds their borders and spreads to the adjacent waters. Nutrient concentrations in many cases exceeded the legal policy limits.

Volatile‐Rich Hydrothermal Plumes Over the Southern Central Indian Ridge, 24°49’S: Evidence for a New Hydrothermal Field Hosted by Ultramafic Rocks

AbstractWater column physico‐chemical studies were conducted over the southern Central Indian Ridge between 24°44’S and 25°52’S to identify and chemically characterize seafloor hydrothermal activity. High turbidity values were observed between 2300 and 2700 m with two distinct layers, between water depths of 2320–2500 m and 2510–2650 m, at two closely spaced CTD stations at 24°48.62’S (CTD‐17‐P5) and 24°48.68’S (CTD‐17‐P8). Elevated concentrations of dissolved Mn (DMn: 19–112 nM), dissolved Fe (DFe: 33–88 nM), methane (CH4: 32–246 nM), elevated δ3He values (28%–88%), and stable carbon isotope ratios of CH4 confirm the hydrothermal origin. In plume layer‐1, the maximum concentrations were observed at 2375m at P8 and in plume layer‐2, the maximum concentrations were observed at 2570 m at P5. The stable isotope ratios of methane (δ13C‐CH4) show that heavier isotopes are enriched (−13.2‰ to −14.7‰) in the plume waters and are similar to vent fluids on the global mid‐oceanic ridges. Further, morphological and mineralogical studies of plume particles, collected from the plume layer‐2 maxima, clearly show the presence of barite, pyrite, chalcopyrite, and indicate possible venting of high‐temperature fluids in the vicinity of P5. Enrichment in methane relative to the other tracers and the general geochemical characteristics of these two plume layers, CH4/Mn (1.8–2.2); CH4/Δ3He (85–97 × 106), Mn/Δ3He (44–46 × 106), Fe/Δ3He (52–54 × 106), indicate that these plumes are formed from fluids released at the seafloor that circulated through ultramafic/gabbroic rocks. The high concentrations of dissolved gases and metals combined with the presence of sulfide particles in the water column provide evidence for a new ultramafic/gabbroic‐hosted hydrothermal vent field, at 24°49’S on the southern Central Indian Ridge.

A Video Plankton Recorder user guide: Lessons learned from in situ plankton imaging in shallow and turbid coastal waters in the Belgian part of the North Sea

Optical imaging devices such as the Video Plankton Recorder (VPR) harness unique capabilities to perform in situ observations and observe planktonic organisms in their natural environmental context. However, applying this technology in shallow and turbid coastal waters comes with a number of challenges. Depending on the research goal, methodological choices need to be made regarding the appropriate towing procedure and instrument settings, like magnification or field of view. In addition, limitations can be expected related to the physical characteristics of the water column, more specifically regarding suspended matter concentration and turbidity. To inform VPR users on the possibilities and limitations of the device in shallow and turbid coastal waters, this paper evaluates a number of specific deployment procedures in the Belgian part of the North Sea (BPNS). For three different towing procedures the practical feasibility, characteristics and output are assessed and the assets and liabilities for each of the tow types are discussed. A Z-shaped and a clover-shaped tow type are seen as best fit for detailed characterization of the plankton community of a limited geographical area. A straight tow type is more suitable for plankton studies over a larger area, with the potential to capture local plankton abundance peaks and to determine the relation with the spatial variation of the environmental conditions. The capacity of the various VPR magnification settings to capture specific plankton taxa or size groups, was tested during four straight line transects with different magnifications. The highest magnification can be used for organisms from 0.3 to 0.7 mm while the low magnification allows to observe larger organisms within the size range of 1.0 to 3.8 mm. Finally, the boundary conditions for the deployment of the VPR related to the turbidity of the water column were defined and the implications for deployment within the study area were investigated. This study shows that high turbidity values over 6.2 NTU inhibit the collection of useable data, complicating the VPR's application in many coastal and transitional waters.

Coastal dynamics on equatorial beaches of amazonian coast during extreme tide events

This paper describes the influence of tidal currents on sediment transport on Amazonian equatorial beaches during extreme events. The study area (Salinópolis city) was divided into two sectors: western (Sampaio tidal channel) and eastern (Atalaia Island). Field surveys were conducted in 2013 during two periods of highest tides: April (the rainy season) and October (the less rainy season and Spring Equinox). The optical backscatter sensors (tide, turbidity, and wave data) and current meter sensors (velocity field data) were programmed to collect data every 0.1 and 60 seconds, respectively. They operated together for 24/12 hours on the upper shoreface (surf zone). Wave heights were higher in the Atalaia Island (up to 1 meter during the less rainy season). The currents were stronger, reaching 1.2 m.s-1, during ebb tide in the rainy season (Sampaio tidal channel). Higher turbidity values (maximum 1,200 FTU) occurred at the Atalaia Island during the less rainy season. The coastal dynamics in the area derives mostly from the Amazonian continental shelf, where intense tidal currents interact with a high volume of particulate debris, especially fine sand in Salinópolis. Nevertheless, estuaries and tidal channels are also largely responsible for sediment supply and play a key role in shoreline stability and coastal transport, especially during extreme tide events.

An Environmental Study for Assessing the Efficiency of the Drinking Water Purification Plant Supplying Some Areas North of Tikrit

The current study is conducted to evaluate the efficiency of the drinking water pu-rification plant supplying for some areas north of Tikrit. The study samples were taken monthly, including a sample from the river outlet of raw water, a sample from the sedi-mentation basin, and the third sample from the drinking water line, starting from August of 2020 until March 2021. The study included, firstly, measuring some environmental factors, including (turbidity, pH, dissolved oxygen, Biochemical oxygen demand , calci-um hardness, magnesium hardness , chloride ion) and secondly, microbial factors (total aerobic plate count, total coliform). The study has recorded high values of turbidity in the winter season, reaching (162.4) nephelometric turbidity unit, while the pH values were tending to be basicity, as their levels ranged between (8.3-7.1). As for the dissolved oxy-gen concentration, it was high in the spring season, reaching (9) mg / Liter and the con-centration of the biochemical oxygen demand was high in the summer season due to the high temperatures, as its concentration reached (4. 3) mg / liter. The chloride ion concen-tration was conformity with compliance with international standards, it ranged between (55.6-32.7) mg / liter. The microbial study, it was found that the water is very polluted, especially in the spring season, as the values of the total number of aerobic bacteria ranged between (17.6-3) × 103 cells / ml, while the values of the total number of coliform bacteria were between (4-4) cells / 100 ml.

Spatio-temporal variations in the water quality of the Doorndraai Dam, South Africa: An assessment of sustainable water resource management

The problem of water scarcity and clean water in sub-Saharan Africa is a growing concern. This study aims to quantify the water quality on a temporal scale in the Doorndraai dam site in sub-Saharan Africa to design possible management options. Here, an integrated approach using both in-situ measurements of water quality parameters and remote sensing data was used to derive the water quality index (WQI) and inherent optical properties of water to deduce the factors governing seasonal and annual variability. The results show that all the water quality parameters analyzed fall under the permissible limit of the World Health Organization (WHO) for drinking water, except turbidity. The average value of turbidity for the dry and wet periods was 12.52 and 3.39 NTU, respectively. WQI value ranges from good to excellent during the wet season, and poor in the dry season owing to the high values of turbidity in the water samples. Both in-situ and remote sensing-based analysis shows that during the last five years, the value of suspended particulate matter (SPM) based on Landsat-8 increased gradually in the study area. The Sentinel-2 derived modified normalized difference water index (MNDWI) shows a decreasing trend in the water area due to encroachment. The strong correlation between in-situ and remote sensing data supports the usefulness of remote sensing techniques for water resource management, especially in data-scarce regions. Looking at the spatio-temporal trend of water quality evolution, the findings of this study will help local decision-makers design sustainable plans for water resource management of Doorndraai dam.

Assessing temporal dynamics on pelagic Sargassum influx and its relationship with water quality parameters in the Mexican Caribbean

Since 2011, massive inflows of pelagic Sargassum have been recorded in the Caribbean region, which has affected coastal ecosystems, mainly water quality and the flora and fauna that inhabit these areas. The aim of this study is to evaluate the temporal dynamics of Sargassum arrival and its relationship on water quality in three sites of the Mexican Caribbean (Mahahual, Xahuayxol and Xcalak). We used remote sensing tools to estimate Sargassum coverage and turbidity to know if these parameters vary throughout the year and are related. We measured in situ water quality parameters to identify variations, depending on the Sargassum quantity and leachate concentration. Our results of 26 Landsat 8-OLI images show higher Sargassum coverage and turbidity during the winter months and a high relationship between Sargassum coverage and turbidity in areas near the coast. Additionally, turbidity calculated from multispectral bands complemented satellite detection of Sargassum, as high turbidity values were identified in near-shore areas where satellite images could not detect the alga. Finally, water quality parameters showed an increase in ammonium concentration and decreased pH and oxygen levels in the areas with higher Sargassum accumulation and leachate concentration. This study provides a better understanding about temporal dynamics of Sargassum influx in the southern Mexican Caribbean and its relationship with water turbidity in order to develop strategies, management plans and harvesting policies that could prevent huge masses of Sargassum reaching the coast.

Exploring the potential greywater use in a typical microcosmic commercial area of South Africa

With water scarcity looming, South Africa needs to be mindful of the way water is used, conserved, or disposed of. By investigating the biological and physical characteristics of grey water, this paper attempted to explore the potential use of grey water within a microcosmic commercial area. Through different methods, samples were tested for Conductivity, Temperature, pH, and Turbidity. Using IDEXX 2000 method, biological characteristics of the grey water (Total Coliform (TC) and E-coli) were tested. At a pH range of 5.8 to 9, Turbidity in the grey water was found to be between 20.1 and 814. The count for TC ranged between 6.83 ×105 – 3.255 ×109 MPN/100 ml, and that for E-coli ranged between 0.1046 ×104 and 0.7701 ×108 MPN/100 ml. The study found that high turbidity values may have serious implications on the perception of people on grey water use as a potential substitute for potable water. However, the low number of E-coli counts suggests that greywater in commercial areas of South Africa may not pose a major health risk to people compared to black water. This paper will contribute to the knowledge about grey water characteristics expected to be encountered when contemplating exploiting grey water in commercial areas around South Africa.

Correlation of turbidity and suspended sediment concentration in natural water flow using alternative data of water plant treatment, case of study in the upper Jundiaí river, Brazil.

Measurements of suspended sediment discharge are greatly significant and represent a basic need for the initial assessment of the effects caused by this process and for the subsequent formulation of management actions. Also, considering that obtaining direct hydrosedimentological data is not a trivial and low-cost task due mainly to the special and temporal variability of the phenomenon, substitute technologies are well employed for monitoring watersheds. Among these are turbidity measurements, described in many papers. An adaptation of this technique was designed and performed in this study for the verification and secondary use of turbidimetric data carried out by a drinking water treatment company at the closing point of the upper part of the Jundiaí river watershed, in the city of Campo Limpo Paulista, São Paulo state. Direct measurements with traditional samplers and valuations of particle size distribution throughout the hydrological year were used to establish empirical correlations between the suspended sediments concentration and turbidity. The definition of the most appropriate adjustment was carried out based on the statistical analysis of the linear regression parameters (R2, Value-p, MSPE, and PRESS) and residue statistics, thus adopting the model with piecewise regression by turbidimetric ranges (250 NTU), which in turn, presented low overestimation of the SSC for high values of turbidity. The definition of the historical series of suspended sediment discharge (SSD)with hourly temporal resolution for the study site validated the main objective of reusing secondary data with hydro-sedimentological purposes, highlighting the plausible applications for different places where there are insufficient resources for the installation and use of in situ turbidity equipment.