Status In Water Research Articles

Identification and assessment of Critical parameters affecting drinking water quality: A case study of water treatment plants of India

Water-borne diseases are common in India and are mostly brought on by shortages and poor quality of potable water. Watercourses receive many effluents, generally residential sewage, due to inadequate sanitation and wastewater treatment. Hence, drinking water treatment plants (DWTPs) face difficulties in meeting the drinking water standards. The current study evaluated the water quality before and after the conventional drinking water treatment process. The water quality was analyzed every month from three major DWTPs in Guwahati, Assam, India for one year. The study showed significant variation in river water turbidity and pathogen levels. During monsoon, river water turbidity reached up to 470 ± 20 NTU, and an increase in pathogen concentration was observed during the dry seasons at low flow conditions. Many times, drinking water turbidity and MPN values exceeded the BIS guideline value in drinking water. The total organic carbon (TOC), one major precursor of disinfection by-products observed in treated drinking water, was found to be in a higher range in water before and after treatment. After treatment, the TOC of (3.25 ± 0.5 mg/L) was found. For better understanding, the water quality was evaluated using the Modified Entropy-weight Water Quality Index (MEWQI) which showed very poor status in the raw water collected from the river Brahmaputra. While the plant's water quality after treatment varied in the category of fair to very good in certain months of the year, but never excellent quality was achieved in any of the selected plants. The results of the sensitivity analysis suggest that turbidity and MPN exhibit the greatest contribution to the WQI of raw water followed by TOC in drinking water. By providing accurate water quality data, this study benefits researchers, policymakers, and water scientists. It also facilitates the adoption of clean production methods to mitigate pollution and enhance water quality.

One-Way Fluid–Structure Interaction Simulation of the Added Damping of T(0,1) Modes of Two Partially Overlapped Identical Plates in Still Water

Abstract Structures with a partially overlapped status in water can be seen in some engineering applications, and the fluid-structure coupling vibration behavior of two partially overlapped identical plates has been studied previously through the experimental method. In this study, the added damping of the T(0,1) modes of two submerged partially overlapped plates is numerically investigated through the one-way fluid-structure interaction (FSI) method. The relevant numerical settings, like the mesh size, calculated periods, time-step size, and vibration amplitude, were tested first. Then, the numerical results were compared with experimental results, and good agreements were found. Finally, numerical results were analyzed. The vibration status of two plates in the joint abutting area or the overlapped area has an important influence on the added mass variation. When the added mass is higher, the phase difference between modal force and vibration displacement is also greater, which is the main reason for the higher added damping. The relationship between the phase difference and the frequency in water can be approximately fitted to a straight line, which can probably be used to predict the added damping variations caused by fluid boundary changes of submerged structures.

Contrasted redox-dependent structural control on Fe isotope fractionation during its adsorption onto and assimilation by heterotrophic soil bacteria.

Despite the importance of structural control on metal stable isotope fractionation in inorganic and abiotic systems, the link between metal structural changes and related isotopic fractionation during reactions with organic surfaces and live cells remains poorly established. We conducted reversible adsorption of Fe(II) and Fe(III) on the surface of exopolysaccharide (EPS)-rich and EPS-poor Pseudomonas aureofaciens, and we allowed Fe intracellular uptake by growing cells. We analyzed the Fe isotopic composition of the remaining fluid and cell biomass, and compared the isotopic fractionation during adsorption and assimilation reaction with relative changes in Fe structural status between aqueous solution and bacterial cells, based on available and newly collected X-ray absorption spectroscopy (XAS) observations. Iron(III) adsorption onto P. aureofaciens at 2.8 ≤ pH ≤ 6.0 produced an enrichment of the cell surface in heavier isotopes with Δ57Fecell-solution ranging from +0.7 to +2.1‰, without a link to pH in EPS-rich cultures. In contrast, the magnitude of isotopic fractionation increased with pH in EPS-poor cultures. Iron(II) adsorption produced an even larger enrichment of the cell surface in heavier isotopes, by up to 3.2‰, tentatively linked to Fe(III) hydroxide precipitation. Intracellular assimilation of Fe(II) favored heavier isotopes and led to Δ57Fecell-solution of +0.8‰. In addition, Fe(III) cellular uptake produced an enrichment of the bacterial biomass in lighter isotopes with Δ57Fecell-solution of -1‰. The XAS analyses demonstrated the dominance of Fe(III)-phosphate complexes both at the cell surface and in the cell interior. We suggest that heavier isotope enrichment of the cell surface relative to the aqueous solution is due to strong Fe(III)-phosphoryl surface complexes and Fe complexation to ligands responsible for metal transfer from the surface to the inner cell. In case of Fe(II) adsorption or assimilation, its partial oxidation within the cell compartments may lead to cell enrichment in heavier isotopes. In contrast, loss of symmetry of assimilated Fe(III) relative to the aqueous Fe3+ ion and longer bonds of intracellular ions relative to aqueous Fe(III)-citrate or hydroxo-complexes could produce an enrichment of cells in lighter isotopes. The versatile nature of Fe(II) and Fe(III) fractionation without a distinct effect of pH and surface exopolysaccharide coverage suggests that, in natural soil and sedimentary environments, Fe isotope fractionation during interaction with heterotrophic bacteria will be primarily governed by Fe complexation with DOM and Fe redox status in the soil pore water.

Antimicrobial Resistance in Escherichia coli and other Coliform Bacteria Isolated from Bagmati River

Objectives: To explore the presence of fecal indicator bacteria and assess antibiotic resistance status in Bagmati river water. Methods: In a cross sectional study during a year 2020; a total of 180 water samples were collected from the Bagmati River’s upstream, midstream, and downstream sources. Maintaining reverse cold chain, the samples were transferred to the laboratory of central department of Microbiology, Tribhuvan University. Organisms were isolated on Eosin Methylene Blue (EMB) and Nutrient Agar. The organisms were further identified based on the biochemical properties and antibiotic susceptibility testing was performed following CLSI (2020) guidelines. Results: Of the 546 isolates, 209 (or 38%) were Escherichia coli. Other coliforms isolated were Enterobacter spp (2%), Citrobacter spp (37%), and Klebsiella spp (23%). Upstream source revealed least percentage 3% (7/209) of E. coli. All the recovered Citrobacter spp. were resistant and E. coli showed >99% resistance towards Tetracycline, Ampicillin and Amoxiclav antibiotics. Klebsiella spp. was 100% resistant towards Ampicillin and Amoxiclav antibiotics. The coliforms exhibited least resistance (10%) towards Chloramphenicol. Based on antibiotic resistance percentage pattern, E. coli showed 27% similarity to Citrobacter spp. Conclusion: Coliforms showed maximum resistance towards first line antibiotics prescribed in human infection. Immediate water safety plans should be instituted to improve the water quality.

Combined effects of water salinity and ammonia exposure on the antioxidative status, serum biochemistry, and immunity of Nile tilapia (Oreochromis niloticus).

Growing Nile tilapia in brackish water showed promising results, but the possibility of ammonia exposure can interrupt health status and productivity. Herein, the study tested the combined effects of water salinity and ammonia exposure on the antioxidative status, serum biochemistry, and immunity of Nile tilapia. Fish were assigned to eight groups where fish were reared in saline water (5, 10, and 15 ppt) with continuous or intermittent (every 3 days) total ammonia (TAN) exposure (5 mg TAN/L) (2 × 4 factorial design). After 30 days, the water salinity, TAN, and their interaction were markedly (P < 0.05), affecting the growth performance (final weight, weight gain, and specific growth rate) and survival rate of Nile tilapia. The growth performance and survival rate were markedly lower in tilapia grown in 15 ppt with continuous TAN exposure than in the remaining groups. The results showed that fish exposed to higher salinity levels (10 and 15 ppt) and continuous TAN exposure had a more robust antioxidative response, as evidenced by higher superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities and lower malondialdehyde (MDA) levels in the homogenates of the gills, intestines, and livers. The gills were notably affected, with congestion of primary filaments blood vessels and degeneration or shedding of secondary filaments epithelium, especially at salinity levels of 10 and 15 ppt. Additionally, the intestines displayed hyperplasia and inflammatory cell infiltration of intestinal mucosa at 5-10 ppt salinity, degeneration and sloughing of the intestinal epithelium at 15 ppt saline water, and increased goblet cell number at salinity of 10 ppt. The study found that continuous TAN exposure had a more significant impact on the fish, especially at higher salinity levels. Water salinity, TAN, and their interaction significantly affected all measured blood bio-indicators (total, albumin, globulin, ALT, AST, creatinine, urea, glucose, and cortisol levels). The phagocytic activity and index were markedly lowered in fish reared in 15 ppt with continuous TAN exposure, while the lysozyme activity was decreased in fish grown in 5, 10, and 15 ppt with continuous TAN exposure. In conclusion, Nile tilapia showed the possibility of growth with normal health status in brackish water (5-10 ppt); however, continuous TAN exposure can impair the productivity of tilapia, especially with high salinity (15 ppt).

Assessment of the Zooplankton Community and Water Quality in an Artificial Freshwater Lake from a Semi-Arid Area (Irbid, Jordan)

Zooplankton play a crucial role in aquatic food chains and contain many species, which could be bioindicators of water quality and ecosystem health. The ecological impacts of eutrophication on zooplankton composition in freshwater lakes have recently gained wide interest. Geographic location and water-body size influence zooplankton diversity in freshwaters; meanwhile, less is known about the composition and dynamic of the zooplankton community and their relationship with the trophic status in artificial water in semi-arid areas. The present study aimed to assess the physical–chemical parameters and to document the seasonal distribution of zooplankton species and their relationship with environmental factors and trophic state in the artificial freshwater lake JUST, in a semi-arid area. The high concentrations of nutrients and the trophic level index (TLI) classified the lake as eutrophic–hypertrophic. The zooplankton in the JUST lake were composed of twenty-six species, with eleven Rotifera, ten Copepoda, and five Cladocera. Copepoda was numerically the most abundant taxon, accounting for 64% of the total zooplankton abundance, in both seasons. However, the second most abundant taxon in summer was Rotifera (28.26%) while in winter it was Cladocera (25.88%). The community structure seemed to be influenced, most likely, by trophic state, phytoplankton abundance, water temperature, dissolved oxygen, and nutrient loading. The zooplankton were largely dominated by bioindicator species of high trophic levels. Zooplankton could be used as a tool to monitor the trophic state of the lake. For sustainable development, the introduction of phytoplanktivorous, aquaculture species, such as carp and koi, will strengthen the top-down control of the phytoplankton concentration, leading to a reduced trophic state.

Methodologies for Water Accounting at the Collective Irrigation System Scale Aiming at Optimizing Water Productivity

To improve water use efficiency and productivity, particularly in irrigated areas, reliable water accounting methodologies are essential, as they provide information on the status and trends in irrigation water availability/supply and consumption/demand. At the collective irrigation system level, irrigation water accounting (IWA) relies on the quantification of water fluxes from the diversion point to the plants, at both the conveyance and distribution network and the irrigated field level. Direct measurement is the most accurate method for IWA, but in most cases, there is limited metering of irrigation water despite the increasing pressure on both groundwater and surface water resources, hindering the water accounting procedures. However, various methodologies, tools, and indicators have been developed to estimate the IWA components, depending on the scale and the level of detail being considered. Another setback for the wide implementation of IWA is the vast terminology used in the literature for different scales and levels of application. Thus, the main objectives of this review, which focuses on IWA for collective irrigation services, are to (i) demonstrate the importance of IWA by showing its relationship with water productivity and water use efficiency; (ii) clarify the concepts and terminology related to IWA; and (iii) provide an overview of various approaches to obtain reliable data for the IWA, on the demand side, both at the distribution network and on-farm systems. From the review, it can be concluded that there is a need for reliable IWA, which provides a common information base for all stakeholders. Future work could include the development of user-friendly tools and methodologies to reduce the bridge between the technology available to collect and process the information on the various water accounting components and its effective use by stakeholders.

Evaluation of physico-chemical and heavy metals status in irrigation, stagnant, and Indus River water at the trans-Himalayan region

The water quality of various resources is changing everywhere, including the high-altitude region, which may have adverse health effects on animals and the human population. So far, not much study has been conducted on high-mountain region water resources. Therefore, this study was conducted at Leh-Ladakh, a high-altitude region, to know the water quality of different sources. For this, water samples were collected from irrigation, stagnant (pond), and Indus river water resources and analyzed different physicochemical parameters as per standard methods and heavy metals using inductively coupled plasma-optical emission spectrometry (Optima 7000 DV, Perkin Elmer) at the laboratory. The results revealed that the total mean values of pH (7.58 ± 0.04), electrical conductivity (EC-243.78 ± 18.05 µS/cm), salinity (0.12 ± 0.01%), total dissolved solids (TDS-121.519.75 mg/L), turbidity (1.17 ± 0.22 NTU) and chemical oxygen demand (COD-31.45 ± 0.73 mg/L) of Indus river water, pH (7.43 ± 0.05), EC (231.86 ± 11.00 µS/cm), salinity (0.11 ± 0.01%), TDS (113.31 ± 5.48 mg/L), turbidity (0.85 ± 0.11 NTU) and COD (29.74 ± 0.49 mg/L) of irrigation water, and pH (7.46 ± 0.03), EC (233.14 ± 11.41 µS/cm), salinity (0.12 ± 0.01%), TDS (115.03 ± 5.78 mg/L), turbidity (0.67 ± 0.13 NTU) and COD (29.65 ± 0.57 mg/L) of pond water were within the prescribed limit by World Health Organization (WHO) for drinking water. However, variances in the range of heavy metals were observed in Indus river water, irrigation water, and in stagnant water at different sites. Our results revealed that the As, Cd, and Pb were above the permissible limit of WHO for drinking water. At the same time, the Ni and Cr levels were observed below the maximum permissible limit. Therefore, these water resources, if used for more extended periods, may pose health-related issues to humans and animals from these elements. So, this study finding will help develop specific mitigation strategies for water management for drinking and other purposes.

Pollution assessment and mapping of potentially toxic elements (PTE) distribution in urban wastewater fed natural wetland, Kolkata, India.

East Kolkata Wetland (EKW) is one of the largest sewage-fed wetlands in the world, which support the livelihood of thousands of peoples. However, at present, EKW system has become ecologically vulnerable due to the discharge of toxic waste through the sewage canal from the Kolkata metropolitan city. Hence, it becomes very important to understand the inflow and load of potentially toxic elements (PTE) in the sediment, water, and fish of sewage-fed wetland used for aquaculture activities. In this study, one of the polluted wetland from EKW, Sardar bherry, was selected as the study area. Sediment samples (45) were collected from 15 sites to characterize the PTEs concentrations levels utilizing inductively coupled plasma mass spectrometry, and their spatial distribution pattern and pollution quality indices were estimated. Water (45) and fish (7) samples were also analyzed to understand the distribution pattern of PTEs from sediment to water and water to fish. The geostatistical prediction map showed that the concentration range of Cr, Fe, Cu, Co, Zn, Cd, Ni, Pb, and Mn in sampling stations were 27.3-84.1 μg g-1, 7281-30193 μg g-1, 50.6-229.7 μg g-1, 4.8-15.3 μg g-1, 113.4-776.9 μg g-1, 10.0-26.9 μg g-1, 23.8-55.7 μg g-1, 9.5-39.3 μg g-1, and 188.6-448.5 μg g-1 respectively. Pollution is alarming in sediment as all of the studied PTEs exceed the threshold effect level according to Sediment Quality Guidelines. Cd levels in sediments were found to be upper than the lowest effect level (LEL), probable effect level (PEL), threshold effect level (TEL), and severe effect level (SEL) for all sample locations. Several pollution assessment indexes (contamination factor, geo-accumulation index, ecological risk index, etc.) also showed that sediment samples were severely polluted by Cd. PTEs status in water and fish is within permissible limits. The study emphasizes that attention should be paid to controlling the excessive accumulation of PTEs in sediment that would further harm the ecological environment and ultimately human health.

Iodine determination in mineral water using ICP-MS: Method development and analysis of brands available in Israeli stores

Reliable iodine determination in drinking water samples has gained importance in the last few decades, mostly due to intensive use of both desalinized water that lacks several important nutritional elements, and bottled mineral water. ICP-MS is a sensitive method for iodine determination that must be performed under alkaline conditions because of the volatile nature of some iodine species. However, in water samples with high pH (>10), slow precipitation of calcium (Ca) and/or magnesium (Mg) carbonates leads to clogging of the ICP-MS nebulizer. We propose preventing this precipitation by adding the chelating agent ethylenediaminetetraacetic acid (EDTA) at 0.1% to a 2% ammonium hydroxide matrix. This concentration of EDTA sufficed for most drinking water samples studied, as long as a 1:1 molar ratio of EDTA to Ca+Mg concentration in the water was maintained. The limit of quantitation of the developed method for iodine was < 0.1 µg L−1. The average iodine concentration in various brands of bottled mineral water sold in Israel was relatively low (average value of seven brands ± standard deviation was 7.67 ± 6.38 µg I L−1). . Regular consumption of either desalinated water or bottled mineral water probably does not supply enough iodine to eliminate iodine deficiency in Israeli consumers. Therefore, continuous follow-up of the iodine status in both tap and bottled water is strongly recommended.

Estimation of the natural background of phosphate in a lowland river using tidal marsh sediment cores

Abstract. Elevated phosphate (PO4) concentrations can harm the ecological status in water by eutrophication. In the majority of surface waters in lowland regions such as Flanders (Belgium), the local PO4 levels exceed the limits defined by environmental policy and fail to decrease, despite decreasing total phosphorus (P) emissions. In order to underpin the definition of current limits, this study was set up to identify the pre-industrial background PO4 concentration in surface water of the Scheldt River, a tidal river in Flanders. We used the sedimentary records preserved in tidal marsh sediment cores as an archive for reconstructing historical changes in surface water PO4. For sediment samples at sequential depths below the sediment surface, we dated the time of sediment deposition and analysed the extractable sediment P. The resulting time series of sediment P was linked to the time series of measured surface water-PO4 concentrations (data 1967–present). By combining those datasets, the sorption characteristics of the sediment could be described using a Langmuir-type sorption model. The calibrated sorption model allowed us to estimate a pre-industrial background surface water PO4 levels, based on deeper sediment P that stabilized at concentrations smaller than the modern. In three out of the four cores, the sediment P peaked around 1980, coinciding with the surface water PO4. The estimated pre-industrial (∼1800) background PO4 concentration in the Scheldt River water was 62 [57; 66 (95 % CI)] µg PO4-P L−1. That concentration exceeds the previously estimated natural background values in Flanders (15–35 µg TP L−1) and is about half of the prevailing limit in the Scheldt River (120 µg PO4-P L−1). In the 1930s, river water concentrations were estimated at 140 [128; 148] µg PO4-P L−1, already exceeding the current limit. The method developed here proved useful for reconstructing historical background PO4 concentrations of a lowland tidal river. A similar approach can apply to other lowland tidal rivers to provide a scientific basis for local catchment-specific PO4 backgrounds.

Pertinent Nutrient Status in Soil and Water of Kargah and Napuras Streams in Gilgit Valley

Aims: To observe the status of salinity build up besides inorganic nutrient status at different sites in Kargah and Napuras streams of Gilgit valley.&#x0D; Study Design: one-way ANOVA means using LSD test.&#x0D; Place and Duration of Study: Kargah and Napuras streams and nearby village in Gilgit valley and the duration of the study was 3 months. &#x0D; Methodology: Soil and water sampling to analyze pertinent salinity parameters besides inorganic nutrient status.&#x0D; Results: Soil and water properties for important salinity parameters were normal at mid point after entering the village areas of Kargah and Napuras streams. Human activities especially to raise crops by applying fertilizers needs to monitor with a specific time scale in order to avoid salinity build up.

Anomalous Fluctuation of Halogens in Relation to the Pollution Status along Lake Mariout, Egypt

This paper aimed to study the anomalous fluctuation of halogens with respect to the pollution status in surface water (w), pore water (p), and sediments (s) of Lake Mariout. It provided a framework for understanding the distribution of dissolved and precipitated halogen salts related to the pollution status of the lake. The study cleared out that bromide was only the most abundant halogen in the three studied partitions. On contrast, sediment’s partition contained the lowest chloride content. Fluoride minerals, especially, fluorapatites and carbonate-fluorapatite (FAP and CFAP), had high Saturation Index (SI) values in surface water (42.77–51.95 and 16.04–60.89, respectively) and in pore water (51.26–54.60 and 17.52–78.33, respectively). Bromide and chloride were mainly found in the soluble forms in the surface water and pore waters. Iodide salts, (Ca(IO3)2 and Ca(IO3)2.6H2O), were moderately precipitated in surface and pore waters. Thus, SI content reflected that halogens, especially fluoride and iodide, played a vital role in reducing lake pollution. Fluorite (CaF2) and sellaïte (MgF2) could only be formed in pore water, while calcite and aragonite could be deposited from surface water. In addition, Cl was mainly found in the forms of NaCl, CaCl2, MgCl2, and KCl in surface and pore waters. The multivariate analysis revealed that fluoride precipitate may serve in decreasing the dissolved salt pollution. Multivariate analysis showed that in the long run, the fluoride precipitation in FAP and CFAP can significantly adsorb and absorb various pollutants and can protect the lake from pollution. The ecological risk assessment conducted by calculating the enrichment factor (EF) showed that the lake was still unpolluted. Regarding human health risks, at appropriate levels of human health and safety, the hazard quotient (HQ) and hazard index (HI) of halogens found to be lower than these reported levels. Hence, ingestion and dermal absorption routes of halogens by surface water and sediments did not pose any adverse effects to population reflecting uncontaminated status of Lake Mariout.

Exploratory study on the spatial relationship between emerging infectious diseases and urban characteristics: Cases from Korea

In the modern global context of interconnected populations, the recent emergence of infectious diseases involves complex interactions. The purpose of this study is to investigate the spatial correlations between urban characteristics, taking into account the socio-ecological aspects, and the emergence of infectious diseases. Using exploratory spatial data analysis and spatial regression between the infectious disease emergence data and 14 urban characteristics, we analyzed 225 spatial units in South Korea, where there was a re-emergence of measles and a 2015 outbreak of Middle East Respiratory Syndrome. As results of exploratory spatial data analysis, the emerging infectious diseases had spatial dependence and showed spatial clusters. Spatial regression models showed that urban characteristic factors had different effects according to the type of infectious disease. Common factors were characteristics related to low socioeconomic status in water or food-borne diseases and manageable infectious diseases. Intermittent infections disease epidemics are related to high-quality residential environments and the response capacity of the local government. New infectious diseases are different than other infectious diseases, which are related to the ecological environment. This study suggests spatial policies for preventing infectious diseases considering the spatial relationships between urban characteristics and infectious diseases as well as the management of public health.

Monitoring of Nutrient Status at Ratargul Swamp Forest in Sylhet, Bangladesh

Nutrient concentration is an important parameter to recognize critical processes of an ecosystem and environmental quality. This paper is based on a study carried out to evaluate the nutrient status in sediments, water and plant leaves from Ratargul swamp forest of Bangladesh during the period from September 2016 to August 2017. The samples were collected from twelve sampling stations of four different canals during dry (September 2016 to April 2017) and wet (May to August, 2017) seasons, respectively. The nutrient contents such as total nitrogen (TN), available phosphorus (AP) and total organic carbon (TOC) were analysed in the laboratory of the Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, Bangladesh. The TN, AP and TOC in sediments were ranged from 2.22 to 5.23, 0.032 to 0.035 and 2.6 to 4.52%, respectively, whereas TN and AP in water were found 5.34 to 22.54% and 0.002 to 0.366%, respectively. Result showed that the TOC in plant leaves was higher in wet season than in dry season, where the TN and AP were higher in dry season than in wet season due to high temperature which increases the rate of photosynthetic activities in the dry season. In both Korochand Hijal plants, the TOC and AP were higher in green leaves than brown leaves, while TN was higher in brown leaves than green ones. Moreover, a statistically significant positive correlation was found among the samples. The study concluded that the nutrient status in sediments, water and leaves were perfectly natural during both the dry and wet season.

Impact of conventional retting of jute (Corchorus spp.) on the environmental quality of water: a case study.

Production of quality jute fibre primarily depends on the retting process of jute. However, the quality of retting water is of great concern because of the scarcity of available water bodies for retting. A study conducted on physico-chemical and microbiological changes in retting water (pre- and post-retting) from four intensively jute-growing districts namely Nadia, North 24 Parganas, Hooghly and South Dinajpur of West Bengal, India, during jute retting. The post-retting water samples recorded lower pH (6.22 to 7.08) and higher EC (electrical conductivity) (0.509 to 0.850ds/m) compared with pre-retting water samples (pH 6.63 to 7.44; EC 0.197 to 0.330ds/m) collected from all the four districts under study. The biological oxygen demand (BOD) and chemical oxygen demand (COD) increased several folds in the post-retting water samples indicating very high microbial growth and activities and depleted oxygen level compared with pre-retting water. The Ca + Mg (calcium + magnesium) content in pre-retting water was high (24.15 to 36.60ppm) which raised further (61.30 to 103.67ppm) in post-retting water, while the bicarbonate content also increased and ranged between 2.72 and 6.81me/l in post-retting water compared with its status in pre-retting water (1.30 to 3.15me/l). The post-retting water was found to be a rich source of nutrients like nitrogen (N), phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn) and copper (Cu) which increased substantially because of jute retting as compared with their status in pre-retting water. The population of pectinolytic, xylanolytic, cellulolytic and ligninolytic bacterial cfu (colony forming unit) increased by 1.5 times in post-retting water as compared with pre-retting water, because these specific bacterial population were involved in the degradation of pectin, xylan, cellulose and lignin during retting of jute. Thus, post-retting water can be judiciously used as a potent source of primary, secondary and micronutrients for succeeding crops besides having higher BOD and COD as a result of higher microbial growth related to jute retting.

Monitoring of Nutritional Status in Sediments, Water and Plant Leaves from Ratargul Swamp Forest at Sylhet in Bangladesh

Monitoring of Nutritional Status in Sediments, Water and Plant Leaves from Ratargul Swamp Forest at Sylhet in Bangladesh

Assessing the ecological health status using macrobenthic communities of tropical coastal water

ABSTRACTThe relative contributions of natural and anthropogenic fluctuations are different in shaping habitat health status and natural benthic communities in tropical coastal water. Understanding responses of coastal benthic communities to these fluctuations are still equivocal and thus available data are inadequate. Here, multiple analytical approaches were used to address the significant risk factors and their impacts on coastal benthic habitat health through space and time. A total abundance of 1436 ± 612 individuals of 33 benthic species were counted and identified from 22 sampling stations across eight sampling periods over the two years of study. Bioassay results showed that the benthic community is moderately exposed to anthropogenic pollutants in Klang Strait coastal water. The results showed that there were no significant temporal changes of habitat health status and macrobenthic community structure; however, spatial changes were significant and synchronized with anthropogenic and natural fluctuations. This study demonstrates that Cd and Hg levels and sediment characteristics played the primary role in shaping the habitat health and macrobenthic assemblages, whereas the influence of other factors were insignificant.

The Role of Hospital Effluent for Occurrence and Distribution of Ecologically Important Antibiotics in Sri Lanka

Antibiotics are among the emerging micro contaminants in the aquatic environment due to their potential adverse effects on the ecosystem and possibly on human health. Four important antibiotic classes, sulfanomides [sulfadiazine (SDI), sulfamethoxazol (SMX)], penicillin [amoxicillin (AMX), ampicilline (AMP)], tetracycline [oxytetracycline (OTC), tetracycline (TET)] and macrolids [erythromycin (ERM)] used for human and veterinary medicine, were studied. Triplicate samples of hospital effluents water and sediment were collected from 50 sampling sites in different area of the country. Solid-Phase Extraction (SPE) was employed to concentrate antibiotics and quantification was done by High Performance Liquid Chromatography (HPLC). Recoveries for each antibiotic were remained between 83%±0.021 to 95%±0.034. Among the selected antibiotics tested; the highest concentrations of AMX and AMP were recorded in hospital effluent water while OTC was not detected. AMX and AMP were ranged between 0.001-0.023 ppm and 0.001-0.024 ppm respectively. The other antibiotics concentrations were; TET (water: 0-0.001 ppm, sediments: N.D); SDI (water: 0.001-0.003 ppm, sediments: 0.001-0.003 ppm); SMX (water: 0.001-0.018 ppm, sediments: 0.001-0.002 ppm); ERM (water: 0.001-0.008 ppm, sediments: 0.001-0.003 ppm) respectively. A relatively high removal efficiency was detected for TET (50-100%) where descending order was followed by SDI (63-72%), SMX (52-72%), ERM (48-100%), AMP (40-54%) and AMX (35-58%) respectively. The results of the study can be incorporated into environmental risk assessments of the particular contaminants as the published information regarding antibiotic contamination status in water and sediment are limited in Sri Lanka. Keywords: Amphicillin (AMP), Amoxicilline (AMX), Sulfadiazine (SDI), Sulfamethoxazol (SMX), Oxytetracycline (OTC), Ttetracycline (TET), High Performance Liquid Chromatography (HPLC)

Appraisal of heavy metal status in water for irrigation usage of the Bangshi River, Bangladesh

An attempt was made to assess the status of heavy metals in the Bangshi River water for irrigation usage. River water was sampled from 20 sampling points for chemical analysis of physicochemical parameters and metal ions. Our analyses revealed that water samples were slightly alkaline to alkaline. All samples had reasonable electrical conductivity, and these samples were from low to medium salinity classes as being fit for irrigation on soils having moderate level of permeability. Water samples were categorized freshwater as per total dissolved solids (TDS). All water samples were excellent indicating low alkalinity hazard, based on sodium adsorption ratio (SAR), but most of the samples were doubtful to unsuitable for soluble sodium percentage (SSP). All samples were free from residual sodium carbonate (RSC) suggesting suitability for irrigation purpose. For water hardness, samples were rated as moderately hard, hard, and very hard. The status of Fe, Zn, Pb, Cd, and Ni in water samples were within permissible levels but Cr, Cu, and Mn content in water samples were in excess of recommended limits and these ions would be considered toxic in long-term irrigation system. Significant relationships existed between EC versus TDS, SAR versus SSP, SSP versus RSC, and SAR versus RSC. There were significant correlations between metal ions: Fe–Cu, Fe–Pb, Cu–Pb, Fe–Mn, Cu–Mn, and Mn–Pb. This finding showed that Cr, Cu, and Mn ions were considered contaminants in river water used for irrigation because the present status of these metals may pose a harmful impact on human health.