scholarly journals Phycocyanin as a proxy for algal blooms in surface waters: case study of Ukerewe Island, Tanzania

2019 ◽  
Vol 14 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Geofrey J. Mchau ◽  
Edna Makule ◽  
Revocatus Machunda ◽  
Yun Yun Gong ◽  
Martin Kimanya
Keyword(s):  
Water Quality ◽  
Redox Potential ◽  
Algal Blooms ◽  
Nitrate Nitrogen ◽  
Quality Parameters ◽  
Water Sources ◽  
Water Quality Parameters ◽  
Total Chlorophyll ◽  
Nitrite Nitrogen ◽  
Reactive Phosphorus

Abstract Knowledge of the parameters that contribute to water body eutrophication is essential for proper monitoring and management of water quality for human consumption. This study assessed water quality parameters in relation to phycocyanin (PC) as a proxy indicator for harmful algal blooms (HABs). Samples were collected from 23 water sources – lakes, wells, springs and boreholes – in selected villages, for six months. Parameters measured included temperature, pH, redox potential, dissolved oxygen, electrical conductivity, total dissolved solids, nitrate nitrogen, nitrite nitrogen, phosphorus, reactive phosphate and total chlorophyll, which were related to (PC) occurrence. The PC concentration detected in Lake Victoria ranged from 5 to 58.4 μg/l above the WHO alert level and exceeded that in other water sources by almost 30 μg/l (P < 0.001). Univariate relationship between water quality parameters and PC indicates association with temperature, redox potential, total chlorophyll, nitrate nitrogen, nitrite nitrogen, phosphate and reactive phosphorus (P < 0.001). The multivariate model indicates that redox potential, nitrate nitrogen and phosphorus are significant statistically (P < 0.05). A predictive model indicates that nitrate nitrogen and reactive phosphorus contribute significantly to PC occurrence whereby unit (1 mg/l) increases in these parameters increase PC by 9.55 and 4.38 μg/l (P < 0.05) respectively. This study demonstrates that water quality parameters can be used to predict increases in PC and hence as a proxy for HABs. It remains important to be able to classify algal blooms, to understand which species are present and their potential cyanotoxin production.

Effects of sampling frequency on estimation accuracies of annual loadings for water quality parameters in different sized watersheds

2020 ◽  
Vol 55 (3) ◽  
pp. 261-277
Author(s):  
Lin Gao ◽  
Junyu Qi ◽  
Sheng Li ◽  
Glenn Benoy ◽  
Zisheng Xing ◽  
...  
Keyword(s):  
Water Quality ◽  
Suspended Solids ◽  
Nitrate Nitrogen ◽  
Sampling Frequency ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Quality Data ◽  
Estimation Errors ◽  
Water Quality Data ◽  
Novel Approach

Abstract Potential errors or uncertainties of annual loading estimations for water quality parameters such as suspended solids (SS), nitrate-nitrogen (NO3-N), ortho-phosphorus (Ortho-P), potassium (K), calcium (Ca), and magnesium (Mg) can be greatly affected by sampling frequencies. In this study, annual loading estimation errors were assessed in terms of the coefficient of variation, relative bias, and probability of potential errors that were estimated with statistical samples taken at a series of sampling frequencies for a watershed in northwestern New Brunswick, Canada, and one of its sub-watersheds. Results indicate that annual loading estimation errors increased with decreasing sampling frequency for all water quality parameters. At the same sampling frequencies, the estimation errors were several times greater for the smaller watershed than those for the larger watershed, possibly due to the flushing nature of streamflows in the smaller watershed. We also found that low sampling frequency tended to underestimate the annual loadings of water quality parameters dominated by stormflow events (SS and K) and overestimate water quality parameters dominated by baseflow (Mg and Ca). These results can be used by hydrologists and water quality managers to determine sampling frequencies that minimize costs while providing acceptable estimation errors. This study also demonstrates a novel approach to assess potential errors when analyzing existing water quality data.

scholarly journals Algal control and enhanced removal in drinking waters in Cairo, Egypt

2015 ◽  
Vol 13 (4) ◽  
pp. 1060-1072 ◽  
Author(s):  
Farida M. S. E. El-Dars ◽  
M. A. M. Abdel Rahman ◽  
Olfat M. A. Salem ◽  
El-Sayed A. Abdel-Aal
Keyword(s):  
Water Quality ◽  
Algal Blooms ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Urban Region ◽  
Multivariate Statistical ◽  
Carbon Reduction ◽  
Outbreak Period ◽  
Greater Cairo ◽  
The Impact

Algal blooms at the major water treatment plants in Egypt have been reported since 2006. While previous studies focused on algal types and their correlation with disinfection by-products, correlation between raw water quality and algal blooms were not explored. Therefore, a survey of Nile water quality parameters at a major water intake in the Greater Cairo Urban Region was conducted from December 2011 to November 2012. Bench-scale experiments were conducted to evaluate the effectiveness of the conventional chloride/alum treatment compared with combined Cl/permanganate pre-oxidation with Al and Fe coagulants during the outbreak period. Addition of permanganate (0.5 mg/L) significantly reduced the chlorine demand from 5.5 to 2.7 mg/L. The applied alum coagulant dose was slightly reduced while residual Al was reduced by 27% and the algal count by 50% in the final treated waters. Applying ferric chloride and ferric sulfate as coagulants to waters treated with the combined pre-oxidation procedure effectively reduced algal count by 60% and better the total organic carbon reduction and residual aluminum in the treated water. Multivariate statistical analysis was used to identify the relationship between water quality parameters and occurrence of algae and to explain the impact of coagulants on the final water quality.

scholarly journals R.A.OLAOYE et al. 2021 Variation of Groundwater and Rainwater Quality in a Nigerian Leper Colony

2021 ◽  
Vol 2 (3) ◽  
pp. 27-33
Author(s):  
Rebecca A. Olaoye ◽  
Akinwale O. Coker ◽  
Mynepalli K. Sridhar
Keyword(s):  
Water Quality ◽  
Water Samples ◽  
Quality Parameters ◽  
Water Sources ◽  
Water Quality Parameters ◽  
World Health ◽  
Slight Variation ◽  
Short Term ◽  
Adequate Treatment ◽  
Bacteriological Parameters

Adequate supply of potable water is a major challenge in most leper colony with emphasis often placed on water needs of “normal” people but little concern on the safe water source for the physically challenged and vulnerable lepers with limited mobility who cannot search for other sources of water outside designated colony. This study was designed to investigate the quality of water sources within a Nigerian leper colony. Periodic characterization of groundwater and rainwater samples was conducted using American Public Health Association (APHA) methods to determine physico-chemical parameters; appearance, odour, colour, taste, chloride, pH, sulphate, copper, zinc, iron, nitrate and bacteriological parameters; coliform organism and Escherichia coli (E-coli) against the world health organization (WHO) drinking water standard. Water samples were clear and odourless. Most of the parameters tested from both sources; groundwater and rainwater were within the recommended standard. Results from short term water quality parameters taken from 2010-2012 were relatively within the same range while the long-term decadal water quality parameters showed slight variation compared to the short term. Heavy metals showed remarkable variation in 2019 while bacteriological parameters from both water sources were above the permissible threshold. For potable use, water sources require adequate treatment. Boiling or disinfection is recommended until water samples have been retested to ascertain that contamination has been eliminated. In addition, home water-treatment through the use of filters, solar disinfection, or flocculants should be provided to make the water safe.

scholarly journals Water Quality and Sediment Profile in Shrimp Culture with Different Sediment Redox Potential and Stocking Densities Under Laboratory Condition

2016 ◽  
Vol 21 (2) ◽  
pp. 65 ◽  
Author(s):  
Wiyoto Wiyoto ◽  
Sukenda Sukenda ◽  
Enang Harris ◽  
Kukuh Nirmala ◽  
Daniel Djokosetiyanto
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Redox Potential ◽  
Sediment Quality ◽  
Stocking Density ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Shrimp Culture ◽  
Two Factors ◽  
Shrimp Density

Sediment quality has been considered as one of the prime factors influencing the environment quality that support maximum shrimp production.The aim of the study was toevaluate the effects of sediment redox potential and shrimp stocking density on the profile of some sediment and water quality parameters. Two factors randomized factorial design was applied, with stocking density (60 and 120 shrimps.m-2) as the first variable and sediment redox potential (-65 mV, -108 mV and -206 mV) as the second variable. Some significant changes in TP, total Mn, and total S concentrations in the sediment were observed after the experimentation (P<0.05). Sediment redox potential significantly affected the dissolved oxygen, TAN, NO2, NO3, and H2S concentrations in the water. Whereas shrimp stocking density affected all water quality parameters except H2S concentration. Significant interactions between redox potential and stocking densities were observed in the nitrite and alkalinity concentrations. The significant effects of both shrimp density and redox potential on the sediment and water parameters in particular those that are known to directly affect the shrimp welfare (e.g. oxygen, ammonia, nitrite and H2S) indicate that these variables are of important aspects in shrimp pond management. Furthermore, the results clearly showed that -206mV redox potential significantly reduced the dissolved oxygen concentration in the sediment-water interface and increased the generation of H2S in water column. Thereby, this redox potential level is not advisable for shrimp culture system. Keywords: redox potential, stocking density.

scholarly journals WATER QUALITY RETRIEVAL AND ALGAL BLOOM DETECTION USING HIGH-RESOLUTION CUBESAT IMAGERY

2021 ◽  
Vol V-3-2021 ◽  
pp. 191-195
Author(s):  
M. Niroumand-Jadidi ◽  
F. Bovolo
Keyword(s):  
Water Quality ◽  
Algal Blooms ◽  
Variable Parameter ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Spatiotemporal Resolution ◽  
Chl A ◽  
In Situ Data

Abstract. Recent advancements in developing small satellites known as CubeSats provide an increasingly viable means of characterizing the dynamics of inland and nearshore waters with an unprecedented combination of high revisits (< 1 day) with a high spatial resolution (meter-scale). Estimation of water quality parameters can benefit from the very high spatiotemporal resolution of CubeSat imagery for monitoring subtle variations and identification of hazardous events like algal blooms. In this study, we present the first study on retrieving lake chlorophyll-a (Chl-a) concentration and detecting algal blooms using imagery acquired by the PlanetScope constellation which is currently the most prominent source of CubeSat data. Moreover, the concentration of total suspended matter (TSM) is retrieved that is an indicator of turbidity. The retrievals are based upon inverting the radiative transfer model. The low spectral resolution (four bands) of PlanetScope imagery poses challenges for such a physics-based inversion due to spectral ambiguities in optically-complex waters like inland waters. To deal with this issue, the number of variable parameters is minimized through inverse modeling. Given the significance of having high-quality water-leaving reflectance for physics-based models, a variable parameter (gdd) is considered to compensate for the atmospheric and sun-glint artifacts. The results compared to the in-situ data indicate high potentials of PlanetScope imagery in retrieving water quality parameters and detection of algal blooms in our case study (Lake Trasimeno, Italy).

scholarly journals A Study on Distribution of Water Quality Parameters in Potable/Ground Waters of Visakhapatnam Coastal Region with Multivariate Factor Analysis

2021 ◽  
Vol 33 (11) ◽  
pp. 2645-2652
Author(s):  
V.V.K.P.L.N. Murty ◽  
P. V.S. Machiraju ◽  
P. Shyamala ◽  
A. Vinod Kumar
Keyword(s):  
Water Quality ◽  
Factor Analysis ◽  
Ground Water ◽  
Water Samples ◽  
Coastal Region ◽  
Quality Parameters ◽  
Water Sources ◽  
Water Quality Parameters ◽  
Ground Waters ◽  
Multivariate Factor Analysis

Chemical components of the earth crust influence the ground water quality. In addition, anthropogenic activities also contribute in deteriorating the quality of ground waters and contaminate the water sources. In present study, 22 water samples were collected from the potable/ground water sources in south coastal region of Visakhapatnam district, India during pre- and post-monsoon seasons and characterized for physico-chemical parameters viz., pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, oxidation reduction potential (ORP), dissolved oxygen (DO), temperature, total hardness (TH), total alkalinity (TA), bicarbonate, carbonate, chloride, fluoride, sulphate, nitrate, phosphate, calcium, magnesium, sodium and potassium. The distribution of parameters was explained by Box-Whisker plot. Further Piper diagrams were drawn to identify the geochemical expressions between the parameters. Multivariate factor analysis was used to assess the degree of factor loadings and to identify the group of parameters influencing the variance of different water quality parameters. The analytical data indicated that majority of water samples in the study area have higher concentration of TDS, TH, TA, Ca2+, Mg2+, Na+, Cl−, HCO3 − and F−.

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