scholarly journals ‘Floc and Sink’ Technique Removes Cyanobacteria and Microcystins from Tropical Reservoir Water

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 405
Author(s):  
Renan Silva Arruda ◽  
Natália Pessoa Noyma ◽  
Leonardo de Magalhães ◽  
Marcella Coelho Berjante Mesquita ◽  
Éryka Costa de Almeida ◽  
...  
Keyword(s):  
Water Column ◽  
Microcystis Aeruginosa ◽  
Laboratory Study ◽  
Combined Treatment ◽  
Natural Soil ◽  
Tropical Reservoir ◽  
Reservoir Water ◽  
Promising Tool ◽  
Biomass Removal ◽  
Polyaluminium Chloride

Combining coagulants with ballast (natural soil or modified clay) to remove cyanobacteria from the water column is a promising tool to mitigate nuisance blooms. Nevertheless, the possible effects of this technique on different toxin-producing cyanobacteria species have not been thoroughly investigated. This laboratory study evaluated the potential effects of the “Floc and Sink” technique on releasing microcystins (MC) from the precipitated biomass. A combined treatment of polyaluminium chloride (PAC) with lanthanum modified bentonite (LMB) and/or local red soil (LRS) was applied to the bloom material (mainly Dolichospermum circinalis and Microcystis aeruginosa) of a tropical reservoir. Intra and extracellular MC and biomass removal were evaluated. PAC alone was not efficient to remove the biomass, while PAC + LMB + LRS was the most efficient and removed 4.3–7.5 times more biomass than other treatments. Intracellular MC concentrations ranged between 12 and 2.180 µg L−1 independent from the biomass. PAC treatment increased extracellular MC concentrations from 3.5 to 6 times. However, when combined with ballast, extracellular MC was up to 4.2 times lower in the top of the test tubes. Nevertheless, PAC + LRS and PAC + LMB + LRS treatments showed extracellular MC concentration eight times higher than controls in the bottom. Our results showed that Floc and Sink appears to be more promising in removing cyanobacteria and extracellular MC from the water column than a sole coagulant (PAC).

scholarly journals Phytoplanktonic associations: a tool to understanding dominance events in a tropical Brazilian reservoir

2007 ◽  
Vol 21 (3) ◽  
pp. 641-648 ◽  
Author(s):  
Ariadne do Nascimento Moura ◽  
Maria do Carmo Bittencourt-Oliveira ◽  
Ênio Wocyli Dantas ◽  
João Dias de Toledo Arruda Neto
Keyword(s):  
Dissolved Oxygen ◽  
Trophic State ◽  
Nitrogen Concentration ◽  
Trophic State Index ◽  
Dry Period ◽  
Tropical Reservoir ◽  
Phytoplankton Assemblages ◽  
Reservoir Water ◽  
Rainy Period ◽  
State Index

The aim of this study was to characterize phytoplankton associations, as well as discuss controlling factors determining algal dominance in a eutrophic tropical reservoir, Mundaú, Pernambuco, Brazil. Water samples were collected during the dry period (January/2005) and the rainy period (June/2005). The samples were collected from both limnetic and littoral regions, and the phytoplankton assemblages identified from current literature after preservation in formaldehyde 4%. At the same time as sampling was done, in situ measurements of water temperature, transparency, dissolved oxygen, and pH were also taken. Total phosphorus, total nitrogen concentration and the Trophic State Index were subsequently determined in the laboratory. Phytoplankton density (ind. L-1) was estimated using an inverted Zeiss microscope. Grouping of the phytoplankton associations was carried out using the Reynolds phytosociological classification. During the dry period, reservoir water showed low dissolved oxygen concentrations, alkaline pH and was relatively turbid compared to the situation during the rainy season. Reservoir water is limited by nitrogen during both seasonal periods. The Trophic State Index is classified as determining eutrophic conditions. Phytoplankton was represented by 70 infrageneric taxa grouped in 16 functional associations, with the majority typical of eutrophic systems. This fact is supported by quantitative analysis, which shows the dominance of S associations comprising exclusively R-strategist cyanobacteria.

Trihalomethanes and haloacetic acid species from the chlorination of algal organic matter and bromide

2011 ◽  
Vol 63 (6) ◽  
pp. 1111-1120 ◽  
Author(s):  
Y. Y. Wei ◽  
Y. Liu ◽  
R. H. Dai ◽  
X. Liu ◽  
J. J. Wu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Fish Oil ◽  
Microcystis Aeruginosa ◽  
Bovine Serum ◽  
Algal Species ◽  
Haloacetic Acid ◽  
Model Compounds ◽  
Reservoir Water

Bromide and algal pollution are important factors influencing disinfection byproduct (DBP) formation and speciation in reservoir water in coastal areas. In this study, the chlorination of model algal cellular compounds (bovine serum albumin, fish oil and starch), Microcystis aeruginosa and its extra-cellular organic matter (EOM) were conducted in the absence and presence of bromide. The main aim of the present study is to explore their potential as precursors for trihalomethanes (THMs) and haloacetic acid (HAAs) speciation upon chlorination in the presence of bromide. The results showed that all brominated THMs species were generated, whereas only bromochloroacetic acid (BCAA) or/and dibromoacetic acid (DBAA) was/were produced as for brominated HAAs (Br-HAAs) from the three model compounds in the presence of bromide. The effect of bromide on Br-HAAs speciation upon fish oil chlorination was more evident than with BSA and starch. There was a good correlation between the species predicted from the model compounds and those obtained from specific algal species. Br-HAAs and Br-THMs species from Microcystis aeruginosa cells or EOM were the same as those from bovine serum albumin in the presence of bromide.

scholarly journals The effects of red soil in removing phosphorus from water column and reducing phosphorus release from sediment in Lake Taihu

2014 ◽  
Vol 69 (5) ◽  
pp. 1052-1058 ◽  
Author(s):  
Lichun Dai ◽  
Gang Pan
Keyword(s):  
Water Column ◽  
Lake Taihu ◽  
Cost Effective ◽  
Phosphorus Release ◽  
Red Soil ◽  
Natural Soil ◽  
P Adsorption ◽  
P Release ◽  
The Cost ◽  
Short Time

A natural red soil and a lanthanum-modified soil (LMS) were tested to compare their phosphorus (P) adsorption capacities and their effectiveness in removing P from the water column and reducing P release from sediment. The equilibrium of P adsorption demonstrated that the maximum P adsorption for the soil was 1.29 and 2.22 mg g−1 at pH 8.5 and 5.5, respectively, and for the LMS these were increased by 45.6 and 77.6% at pH 8.5 and 5.5, respectively, indicating that the soil was effective in P adsorption and the doping of lanthanum could substantially increase P adsorption. The sediment–water column incubation showed that, due to the P adsorption of the soil and LMS, the total P in the water column decreased by 58.5, 60.6, 68.2 and 77.2% for 180 g m−2 soil, 900 g m−2 soil, 180 g m−2 LMS and 900 g m−2 LMS treated systems, respectively, in a short time (6 h), and the capping layer substantially reduced the P release from sediment during column incubation, indicating that the soils were effective in reducing internal P load. However, considering the cost of LMS, the natural soil was suggested to be a cost-effective material to control internal P load.

Atmospheric correction assessment of SPOT-6 image and its influence on models to estimate water column transparency in tropical reservoir

2016 ◽  
Vol 4 ◽  
pp. 158-166 ◽  
Author(s):  
Luiz H.S. Rotta ◽  
Enner H. Alcântara ◽  
Fernanda S.Y. Watanabe ◽  
Thanan W.P. Rodrigues ◽  
Nilton N. Imai
Keyword(s):  
Water Column ◽  
Atmospheric Correction ◽  
Tropical Reservoir

scholarly journals Diel vertical migration of Cladocera in a compartment of a tropical reservoir

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Erika dos Santos Silva ◽  
Odete Rocha ◽  
Maria José dos Santos-Wisniewski
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Chlorophyll A ◽  
Vertical Migration ◽  
Variable Temperature ◽  
Chemical Properties ◽  
Migration Pattern ◽  
Limiting Factor ◽  
Tropical Reservoir ◽  
Physical And Chemical

Abstract Aim This study seeks to analyze the vertical migration pattern of Cladocera species as related with the physical and chemical parameters of the water. Methods Samplings were carried out at 3-h intervals for 24 h in January 15 on the Sapucaí River compartment of Furnas reservoir, Minas Gerais State, Brazil. These samples were taken at five depths, from the surface to the near-bottom layer (0, 2, 4, 6, 8, and 9 m) totalizing 54 samplings for each limnological variable (temperature, pH, dissolved oxygen, electrical conductivity, chlorophyll-a content, Index of Trophic State, water transparency and Cladocera populations abundance). The samplings were performed at the limnetic region at a point with total depth of 9 meters. Results Water column thermal and chemical stratifications and thermocline occurrences were registered in the middle of the day. Among the 14 Cladocera species, only Ceriodaphnia cornuta and C. silvestrii displayed a significant migration pattern, which was mainly related to chlorophyll-a and dissolved oxygen concentrations. Diaphanosoma birgei and D. spinulosum are found at high densities near the surface and low ones in depth. The migration of Diaphanosoma was directly related to the concentration of chlorophyll a and pH, thus acting as a limiting factor. Feeding at high temperatures in the surface layer and assimilating at lower ones in depth, usually confer metabolic advantages to the vertically migratory species. Conclusions In this study, a well-defined pattern of vertical migration was found for two Cladocera species and its possible causes were hypothesized. To the species with less locomotory capacity, thermal and chemical stratifications can act as barriers to migration and distribution through the water column. This pattern may probably be found for zooplankton species in other compartments of Furnas reservoir, with similar physical and chemical properties.

scholarly journals Hydrochemistry and trophic state change in a large reservoir in the Brazilian northeast region under intense drought conditions

2016 ◽  
Author(s):  
Janaina A. Santos ◽  
Rozane V. Marins ◽  
José E. Aguiar ◽  
Guillermo Challar ◽  
Francisco A.T.F. Silva ◽  
...  
Keyword(s):  
Water Column ◽  
Trophic State ◽  
Anthropogenic Activities ◽  
Water Volume ◽  
Semiarid Region ◽  
Trophic State Index ◽  
Reservoir Water ◽  
Worst Case ◽  
Large Reservoir ◽  
Reservoir Volume

<p>The study shows changes on physical and chemical water parameters and of trophic state in a large reservoir in the Brazilian semiarid region following decreasing reservoir volume due to rainfall shortage during four consecutive years. The monitoring period, between November 2011 and May 2014, assessed approximately 50% water volume reduction and 10 meters’ decrease of reservoir water level that degraded water quality. Decrease in reservoir volume, strong evaporation and the permanent influence of anthropogenic activities, favored the concentration of salts and accumulation of nutrients and of increasing pH. Thermal stratification of the water column occurred when volume was maximum and lead to a significant reduction in dissolved oxygen in the hypolimnion (0.07 to 2.62 mg L<sup>-1</sup>). Diminishing volume resulted in mixing of the hypolimnion nutrient-rich and oxygen-poor waters in the entre water column and changed the initial oligotrophic condition to eutrophic. However, the temporal scale of the response of the reservoir's trophic state differs in the different areas of the reservoir. Whereas deeper areas accumulating nutrients from aquaculture and agriculture progressively became mesotrophic and eventually eutrophic; shallower regions far from direct anthropogenic influences, changed their trophic sate much later, but rapidly turned into super-eutrophic conditions, probably due to more intense sediment resuspension and water mixing. Trophic State Index followed nutrient increase during most of the period. However, it also responded to an increase in chlorophyll <em>a </em>concentrations when the reservoir achieved its minimum volume, in particular in the shallower areas. The results suggest that this type of reservoir systems are vulnerable to eutrophication during extended drought periods and that a better assessment of the maximum support capacity for reservoir activities, particularly aquaculture, must be re-assessed taking into consideration worst case scenarios forecasted by global climate change. </p>

scholarly journals Accelerated eutrophication and toxicity in tropical reservoir water and sediments: an ecotoxicological approach

2016 ◽  
Vol 25 (14) ◽  
pp. 13292-13311 ◽  
Author(s):  
A. C. Rietzler ◽  
C. R. Botta ◽  
M. M. Ribeiro ◽  
O. Rocha ◽  
A. L. Fonseca
Keyword(s):  
Tropical Reservoir ◽  
Reservoir Water

scholarly journals Monitoring of Cyanobacteria in Water Using Spectrophotometry and First Derivative of Absorbance

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 124 ◽  
Author(s):  
Adogbeji Valentine Agberien ◽  
Banu Örmeci
Keyword(s):  
Detection Limit ◽  
Surface Water ◽  
Microcystis Aeruginosa ◽  
Negative Impact ◽  
Quality Parameters ◽  
Deionized Water ◽  
Derivative Spectrophotometry ◽  
First Derivative ◽  
Promising Tool ◽  
Low Concentrations

Management of cyanobacteria blooms and their negative impact on human and ecosystem health requires effective tools for monitoring their concentration in water bodies. This research investigated the potential of derivative spectrophotometry in detection and monitoring of cyanobacteria using toxigenic and non-toxigenic strains of Microcystis aeruginosa. Microcystis aeruginosa was quantified in deionized water and surface water using traditional spectrophotometry and the first derivative of absorbance. The first derivative of absorbance was effective in improving the signal of traditional spectrophotometry; however, it was not adequate in differentiating between signal and noise at low concentrations. Savitzky-Golay coefficients for first derivative were used to smooth the derivative spectra and improve the correlation between concentration and noise at low concentrations. Derivative spectrophotometry improved the detection limit as much as eight times in deionized water and as much as four times in surface water. The lowest detection limit measured in surface water with traditional spectrophotometry was 392,982 cells/mL, and the Savitzky-Golay first derivative of absorbance was 90,231 cells/mL. The method provided herein provides a promising tool in real-time monitoring of cyanobacteria concentrations and spectrophotometry offers the ability to measure water quality parameters together with cyanobacteria concentrations.

scholarly journals Aerobic and anaerobic mineralization of Salvinia molesta and Myriophyllum aquaticum leachates from a tropical reservoir (Brazil)

2011 ◽  
Vol 23 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Renato Henriques da Silva ◽  
Rafael Spadaccia Panhota ◽  
Irineu Bianchini Junior
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Organic Carbon ◽  
Water Sample ◽  
Aquatic Macrophytes ◽  
Salvinia Molesta ◽  
Myriophyllum Aquaticum ◽  
Tropical Reservoir ◽  
Reservoir Water ◽  
Aerobic And Anaerobic

AIM: This study aimed at describing and discussing the leachates mineralization (aerobic and anaerobic) of two species of aquatic macrophytes (Salvinia molesta and Myriophyllum aquaticum) from a tropical reservoir (22° 00' S and 47° 54' W); METHODS: The incubations were prepared with plant leachates and reservoir water sample and were maintained during 45 days in the dark (at 20 °C). The organic carbon and the oxygen consumption kinetics were evaluated; RESULTS: Irrespective of to the experimental condition, the leachates were mainly utilized for catabolic processes (i.e., respiration), mineralization was slightly faster in an aerobic environment (1.22 fold) and in this condition, the yield of refractory products was smaller (2.3%); the O/C stoichiometric ratios values (oxygen consumed per atom of carbon) from mineralization of the 2 types of leachates were similar (ca. 1.12); CONCLUSIONS: According to these results we conclude that the leachate from selected macrophytes is rapidly decomposed and subsidize primariy the microbial catabolism (aerobic or anaerobic); in addition, we propose that S. molesta contributes more to the input of dissolved organic matter within the reservoir.

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