Assessing heavy metal and physiochemical pollution load of Danro River and its management using floating bed remediation

River Danro in Garhwa (India) plays a vital role as a significant source of surface water and a crucial tributary of the North Koel River, ultimately joining the Ganga River Basin. Serving both urban-industrial and rural areas, the region faces challenges, including sand mining near Belchampa Ghat. This study aimed to assess physicochemical and heavy metals pollution at nine sampling locations, utilizing the Overall Index of Pollution (OIP), Nemerow Pollution Index (NPI), and Heavy Metal Pollution Index (HPI). OIP values indicated excellent surface water quality (0.71) in non-monsoon and slight pollution (6.28) in monsoon. NPI ranged from 0.10 to 1.74 in non-monsoon and from 0.22 (clean) to 27.15 (heavily polluted) in monsoon. HPI results suggested groundwater contamination, particularly by lead. Principal component analysis (PCA) and geospatial mapping showed similar outcomes, highlighting the influence of adjacent land use on water quality. Recognizing the significance of the Danro River in sustaining life, livelihoods, and economic growth, the study recommends implementing measures like floating bed remediation and regulatory actions for effective river management. The study acknowledges weaknesses in the current practical assessment methods for water contamination. These weaknesses make it difficult to put plans for cleaning up and controlling contamination into action. Because of this, future research on developing new in-place remediation techniques should focus on creating better ways to measure how effective the cleanup is.

How the physicochemical substrate properties can influence the deposition of blood and seminal deposits

A comprehensive investigation into the impact of the physical and chemical variables of a substrate on the deposition was conducted to aid in the estimation of the subsequent transfer probabilities of blood and semen. The study focussed on surface roughness, topography, surface free energy (SFE), wettability, and the capacity for protein adsorption. Conjointly, evaluations of the physical and chemical characteristics of blood and seminal deposits were conducted, to assess the fluid dynamics of these non-Newtonian fluids and their adhesion potential to aluminium and polypropylene. A linear range of surface roughness parameters (0.5 - 3.5 µm) were assessed for their impact on the deposit deposition spread and adhesion height, to gather insight into the change in fluid dynamics of non-Newtonian fluids. Blood has shown to produce a uniform adhesion coverage on aluminium across all roughness categories while blood deposited on polypropylene exhibited a strong hydrophobic response from a surface roughness of 2.0 µm and beyond. Interestingly, the deposition height of blood resulted in near identical values, whether deposited onto the hydrophobic polypropylene or the hydrophilic aluminium substrate, illustrating the potential influence of a heightened fibrinogen adsorption effect. Semen deposited on aluminium resulted in concentrated localised deposition regions after reaching a surface roughness of 2.0 µm, highlighting the development of crystal formations afforded by the sodium ion concentration in the seminal fluid. The semen deposited on polypropylene conformed to the substrate contours producing a deposition film that was smoother than the substrate itself, underlining the effects of thixotropic fluid dynamics. Variables identified here establish the complexity observed for non-Newtonian fluids, and the effect protein adsorption may have on the deposition behaviour of blood and seminal deposits and inform questions in relation to the adhesion strength of said deposits and their ability to dislodge (becoming detached upon the application of an external force) from the substrate surface during a potential transfer event.

How changes to the substrate's physical characteristics can influence the deposition of touch and salivary deposits

An in-depth study into the physical substrate characteristics such as substrate surface roughness, topography, and physicochemical characteristics like wettability and surface free energy (SFE) was conducted to investigate the impact on the deposition and adherence of touch and salivary deposits on aluminium and polypropylene. A robust protocol was established to generate a set of substrates with a controlled linear surface roughness range (0.5-3.5 µm) in order to identify the impact of surface roughness on DNA transfer, persistence, prevalence, and recovery (DNA-TPPR). The polypropylene substrate was shown to produce fibres when artificially roughened, becoming more prominent at a higher surface roughness range, and has shown to have a direct impact on the distribution of salivary and touch deposits. At the low to moderate surface roughness range 0.5-2.0 µm, salivary and touch deposits have generally shown to follow the topographical features of the substrate they were deposited on, before a plateau of the surface roughness measure on the deposit was observed, indicating that a saturation point was reached and the grooves in the substrate were beginning to fill. Touch deposits have shown to maintain a consistent deposition height pre-surface roughness threshold, irrespective of substrate surface roughness while the deposition height of salivary deposits was heavily influenced by substrate surface roughness and topography. The substrate SFE, wettability, hydrophobicity, and the surface tension of the deposit was shown to drive the adhesion properties of the saliva and touch deposits on the respective substrates, and it was observed that this may be of importance for the improvement of the current DNA-TPPR understanding, DNA sampling protocols, and DNA transfer considerations within casework.

Classification of local diesel fuels and simultaneous prediction of their physicochemical parameters using FTIR-ATR data and chemometrics

Class identification and prediction of physicochemical variables of eight diesel fuel brands collected from several stations within the Atlanta metropolitan area in the State of Georgia were investigated using principal component analysis (PCA), partial least squares discriminant analysis (PLS2-DA), and partial least squares regression (PLSR) as modeling techniques. The fuels were from a common pipeline, therefore, assumed to have very similar characteristics. Ten FTIR-ATR spectra per fuel brand were collected over the 650 - 4000 cm^-1 mid-infrared region, and the 80 x 3351 matrix was submitted to PCA to determine if there were any clusters. Following PCA, the 80 x 3351 matrix was split into a training matrix (56x3351) and a test matrix (24x3351). PLS2-DA models were built and evaluated for class identification using dummy variables (I,0) as input matrix. For physicochemical variable predictions, models were developed via PLSR using the FTIR-ATR spectra training matrix and physicochemical variables obtained from the Georgia Department of Agriculture Labs as input. Correlation coefficients of the eight fuels ranged from 0.9960 to 0.9998. PCA revealed all eight clusters of the diesel fuels, regardless of the tight correlation coefficients range. With a 1.0 ± 0.1 cut-off for fuel identification, the PLS2-DA models showed 100% correct predictions for four or five fuel brands, and 75% correct prediction for all eight fuel brands. PLSR predicted 100% correct physicochemical variables, with a RMSEP range of 0.019 to 1.132 for all 80 variables targeted.

Spatial and seasonal dynamics of phosphorous and physicochemical variables in the Negro River Estuary (Argentina): a preliminary approach

Nutrient discharge into rivers and estuaries and the factors that control it need to be further understood to decrease the risk of harmful algae blooms on these ecosystems. Preliminary seasonal physicochemical parameters at six stations along the Negro River Estuary (Argentina) were studied during 2019 (Austral summer, winter, and spring) with high- and low-frequency data. Three of the stations were mainly estuarine-influenced and three were marine-influenced ones. The concentration of phosphate (P), river discharge, meteorological conditions, seasonality, and physicochemical variables were analyzed. Total phosphorus (TP) showed seasonal variations and was higher than previously reported for the upper watershed in all stations in the warmer months, except for the marine control one. Orthophosphate values were also high compared to previous watershed data and changed independently of TP fluctuations. Changing turbidity, water temperature, pH, and conductivity did not appear to have an essential role in phosphorus variations. An unexplained high TP spike in the late spring sample shows the need for further research in the area, while the seawater mixing with P-rich river water could be acting as a dilution agent at the mouth of the river.

Spatial and seasonal variations in coastal water characteristics at Kalpakkam, western Bay of Bengal, Southeast India: a multivariate statistical approach

A study was carried out in the coastal waters of Kalpakkam with the objectives to evaluate the seasonality in hydrobiological parameters in surface and bottom waters, and assess the anthropogenic stress and monsoonal flux on a spatiotemporal scale. The study covered an area of approximately 100 km² in the coastal environment. Relatively high values for pH, temperature, and TP were observed during the post-monsoon (POM) season. The monsoon (MON) season was linked with TN, ammonia, and DO concentrations as all these parameters have shown increased values during this season due to freshwater input. The summer (SUM) season was characterized by salinity, turbidity, nitrate, phosphate, and silicate, indicating a true marine environmental condition for plankton production. Principal component analysis (PCA) and cluster analysis (CA) indicated the presence of distinct coastal water masses with respect to seasons and sampling regions. The spatial pattern indicated the distinctness of the coastal nearshore water (CNW) and coastal offshore water (COW) with respect to water quality. The CNW was more dynamic due to direct external influence as compared to the relatively stable COW environment. Similarly, the study region in the northern part, which is continuously exposed to the backwater inputs and tourism activities, was statistically different from the southern part.

Physicochemical and metal composition of rainfall in the Johannesburg region, South Africa

The change in the water quality of rainfall impacts water supply through the contamination of surface water and groundwater. The presence of potential sources for metals in the form of aerosol through atmospheric transportation from gold tailings dams, coal mines, and coal-fired power stations increases the risk of water quality deterioration in the Johannesburg region. Rainfall monitoring was conducted for one hydrological year. Rainfall amount was measured, and samples were collected for stable isotope and metal analysis. Some metals show very high concentration in the rainfall with a decreasing order from zinc, cadmium, copper to lead. Their presence in the water is not desirable, as a result of favourable pH and Eh conditions in the rainfall with contaminant inputs from the gold tailing dams, coal mines, and coal-fired power stations. Therefore, the Johannesburg rainfall can be considered as potentially toxic due to the constant input of meals into water supply dams and aquifers recharged by the rainfall.

Assessment of spatial and temporal variations in water quality by the application of multivariate statistical methods in the Kali River, Uttar Pradesh, India

The Kali River is a significant source of surface water as well as the main tributary of River Hindon that flows through major cities of western Uttar Pradesh, India. It flows throughout the urban and industrial regions; hence, it carries various amounts of pollutant. Therefore, a study was conducted to examine spatial-temporal variations in river water quality by determining physicochemical variables and heavy metal concentrations at seventeen sampling stations (S₁-S₁₇) throughout the river stretch. Various physicochemical variables, namely pH, EC, TDS, turbidity, BOD, COD, TH, TA, Ca, Mg, Na, K, HCO₃^-, Cl^-, SO₄^2-, NO₃^-, and PO₄^3- were higher in summer than in winter. The order of mean metal concentrations was Fe > Pb > Mn > Ni > Zn > Cu > Cr > Cd. The relationships among measured physicochemical variables and pollution index were examined. Furthermore, multivariate statistical methods were used to assess spatial-temporal variation in water quality to identify current pollution sources and validate results. Water quality index and comprehensive pollution index indicated that the Kali River was less polluted from S₁ to S₈. However, downstream sampling sites were polluted. Pollution starts from S₉ and drastically increases at and beyond S₁₃ because of effluents from industries and sugar mills in Muzaffarnagar. The study suggests cleaning the downstream region of river to restore human health and flora and fauna in the river ecosystem.

Influence of human-induced pressures on dissolved and particulate metal concentrations in a South American estuary

Coastal areas are urbanized and industrialized environments, affected by dredging operations, discharges of untreated municipal wastewaters, and farming. Developing countries are in continuous growth and will deal, in a close future, with the highest rate of coastal transformation, posing serious risks for the ecological and environmental value of ecosystem assets. This research aims to study the dissolved and particulate Cr, Ni, Pb and Zn values within an argentinean estuarine environment which is currently under human-induced pressures. Concentrations of all the metals under analyses showed seasonal variability of both dissolved and particulate metals. An important outcome of this study was that dissolved Cr, Pb and Zn attained maximum values and overall increased concentrations with respect to previous records from the same area. Indeed, the highest concentrations were found during the dredging operations or in association with increases in the metal levels from wastewater discharges. The results also indicated that human activities contributed the least to the dissolved Ni concentrations. The particulate fraction of Cr, Ni and Zn showed an upward trend in the concentrations, particularly during the last two sampling dates, being also positively correlated between each other. Regarding their respective environmental quality standards, many samples achieved dissolved Cr and Zn concentrations above the maximum values recommended by international guidelines. Thus, this study highlights the possibility of stressors like dredging activities and municipal wastewaters to cause increases in the water column pollution levels.

Spatiotemporal dynamics of Phormidium cover and anatoxin concentrations in eight New Zealand rivers with contrasting nutrient and flow regimes

Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are a major concern in many countries due to their increasing extent and severity. The aim of this study was to improve the current understanding of the dominant physicochemical variables associated with high Phormidium cover and toxin concentrations. Phormidium cover and anatoxin concentrations were assessed weekly for 30weeks in eight predominately cobble-bed rivers in the South Island of New Zealand. Phormidium cover was highly variable both spatially (among and within sites) and temporally. Generalized additive mixed models (GAMMs) identified site, month of the year, conductivity and nutrient concentrations over the accrual period as significant variables associated with Phormidium cover. Cover was greatest under low to intermediate accrual dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations. Accrual nutrients had a strong, negative effect on cover at concentrations>0.2mgL^-1 DIN and 0.014mgL^-1 DRP. The effect of flow was generally consistent across rivers, with cover accruing with time since the last flushing flow. Total anatoxins were detected at all eight study sites, at concentrations ranging from 0.008 to 662.5mgkg^-1 dried weight. GAMMs predicted higher total anatoxin concentrations between November and February and during periods of accrual DRP<0.02mgL^-1. This study suggests that multiple physicochemical variables may influence Phormidium proliferations and also evidenced large site-to-site variability. This result highlights a challenge from a management perspective, as it suggests that mitigation options are likely to be site-specific.

[Spatial and seasonal characterization of the drinking water from various sources in a peri-urban town of Salta]

Drinking water monitoring plans are important to characterize both treated and untreated water used for drinking purposes. Access to drinking water increased in recent years as a response to the Millennium Development Goals set for 2015. The new Sustainable Development Goals aim to ensure universal access to safe drinking water by 2030. Within the framework of these global goals, it is crucial to monitor local drinking water systems. In this paper, treated and untreated water from different sources currently consumed in a specific town in Salta, northern Argentina, was thoroughly assessed. Monitoring extended along several seasons and included the physical, chemical and microbiological variables recommended by the Argentine Food Code. On the one hand, treated water mostly complies with these standards, with some non-compliances detected during the rainy season. Untreated water, on the other hand, never meets microbiological standards and is unfit for human consumption. Monitoring seems essential to detect anomalies and help guarantee a constant provision of safe drinking water. New treatment plants are urgently needed to expand the water grid to the entire population.

Fragmentation and groundwater supply as major drivers of algal and plant diversity and relative cover dynamics along a highly modified lowland river

Algae and aquatic vascular plants were investigated along a highly modified medium-sized lowland river (Oglio River, northern Italy). We focused on the role of fragmentation and groundwater supply in driving macrophyte assemblages, paying particular attention to soft-bodied benthic algae. Four different a priori stretch types (dammed, groundwater-dependent, potamal and rhithral) were identified along the river longitudinal gradient as proxies of river hydrology and relative human-induced flow alterations. Over three years (2009-2011), taxa diversity, cover data, spatial and temporal dynamics and indicator and detector species were compared with physical, chemical and hydrological variables at 30 different river sites. Data was explored by indicator species analysis, nonmetric multidimensional scaling, and PROTEST. A total of 88 taxa, of which 36 were algae (equal to 40.9% of the total diversity), 3 bryophytes (3.4%) and 49 vascular plants (55.7%), were recorded. Taxa diversity peaked at the groundwater-dependent sites for both algae and vascular plants (with a mean of 12.8±2.7 and 12.7±4.8 taxa per site, respectively). Algae cover values were one order of magnitude higher than those of vascular plants (with an overall mean of 37.0±24.2% per site). The vascular plants counterbalanced the algae coverage values exclusively at the dammed sites (27.6±23.2% vs 28.2±13.9%, respectively). A clear zonation of communities emerged from the multivariate analysis, which revealed taxa rearrangements that largely overlapped the river stretch types. Inter-annual comparisons confirmed the strong stability of the primary producer communities in the short term (three years). Our work substantiates the pivotal role played by fragmentation and hydrology, in addition to groundwater, in structuring riverine macrophyte communities. Further investigations are needed to resolve the uncertainty surrounding the non-linear responses of macrophytes to the physical and chemical conditions of rivers.

The effects of physicochemical variables and tadpole assemblages on microalgal communities in freshwater temporary ponds through an experimental approach

BACKGROUND

In freshwater systems, microalgae are the major biomass of microorganisms. They occur in ecosystems that are largely structured by the climatic regime, the physical and chemical environments with which they interact, and the biological interactions that occur within them. Amphibian larvae are most present in standing water habitats where they are important primary and secondary consumers and even predators. Studies conducted in America and Europe have shown that tadpoles play an important role in the regulation of the algal community structure and water quality in ecosystems. This article aimed to study the effects of the physicochemical variables and tadpole assemblages of four species on microalgae in artificial freshwater ponds using an experimental approach in the Pendjari area, a flora and fauna reserve located in the extreme north-west of Benin.

RESULTS

The species of phytoplankton and periphyton recorded in ponds were among the taxonomical groups of chlorophytes, cyanophytes, euglenophytes, diatoms and dinoflagellates. Chlorophytes were the dominant group in the algal communities. Physicochemical variables affected the biomass of the different communities of algae in temporary freshwater ponds. Transparency and pond size were the most determinative variables of the structure of microalgae communities in ponds. Tadpoles of Kassina fusca, Ptychadena. bibroni, and Phrynomantis microps were important for the regulation of the water quality and algal community structure by grazing and filter-feeding.

CONCLUSIONS

A decrease in the tadpole population in the artificial temporary ponds due to predation by carnivorous tadpoles of Hoplobatrachus occipitalis caused a disturbance of the algal community structure. This means that the decline of the amphibian population will critically lead to the impoverishment of ecosystems, thereby negatively influencing aquatic and terrestrial ecosystems.