scholarly journals The Use of Biochar and Pyrolysed Materials to Improve Water Quality through Microcystin Sorption Separation

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2871
Author(s):  
Vladimír Frišták ◽  
H. Dail Laughinghouse ◽  
Stephen M. Bell

Harmful algal blooms have increased globally with warming of aquatic environments and increased eutrophication. Proliferation of cyanobacteria (blue-green algae) and the subsequent flux of toxic extracellular microcystins present threats to public and ecosystem health and challenges for remediation and management. Although methods exist, there is currently a need for more environmentally friendly and economically and technologically feasible sorbents. Biochar has been proposed in this regard because of its high porosity, chemical stability, and notable sorption efficiency for removing of cyanotoxins. In light of worsening cyanobacterial blooms and recent research advances, this review provides a timely assessment of microcystin removal strategies focusing on the most pertinent chemical and physical sorbent properties responsible for effective removal of various pollutants from wastewater, liquid wastes, and aqueous solutions. The pyrolysis process is then evaluated for the first time as a method for sorbent production for microcystin removal, considering the suitability and sorption efficiencies of pyrolysed materials and biochar. Inefficiencies and high costs of conventional methods can be avoided through the use of pyrolysis. The significant potential of biochar for microcystin removal is determined by feedstock type, pyrolysis conditions, and the physiochemical properties produced. This review informs future research and development of pyrolysed materials for the treatment of microcystin contaminated aquatic environments.

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 380
Author(s):  
Floriane Boullot ◽  
Caroline Fabioux ◽  
Hélène Hégaret ◽  
Pierre Boudry ◽  
Philippe Soudant ◽  
...  

Pacific oysters (Crassostrea gigas) may bio-accumulate high levels of paralytic shellfish toxins (PST) during harmful algal blooms of the genus Alexandrium. These blooms regularly occur in coastal waters, affecting oyster health and marketability. The aim of our study was to analyse the PST-sensitivity of nerves of Pacific oysters in relation with toxin bio-accumulation. The results show that C. gigas nerves have micromolar range of saxitoxin (STX) sensitivity, thus providing intermediate STX sensitivity compared to other bivalve species. However, theses nerves were much less sensitive to tetrodotoxin. The STX-sensitivity of compound nerve action potential (CNAP) recorded from oysters experimentally fed with Alexandrium minutum (toxic-alga-exposed oysters), or Tisochrysis lutea, a non-toxic microalga (control oysters), revealed that oysters could be separated into STX-resistant and STX-sensitive categories, regardless of the diet. Moreover, the percentage of toxin-sensitive nerves was lower, and the STX concentration necessary to inhibit 50% of CNAP higher, in recently toxic-alga-exposed oysters than in control bivalves. However, no obvious correlation was observed between nerve sensitivity to STX and the STX content in oyster digestive glands. None of the nerves isolated from wild and farmed oysters was detected to be sensitive to tetrodotoxin. In conclusion, this study highlights the good potential of cerebrovisceral nerves of Pacific oysters for electrophysiological and pharmacological studies. In addition, this study shows, for the first time, that C. gigas nerves have micromolar range of STX sensitivity. The STX sensitivity decreases, at least temporary, upon recent oyster exposure to dinoflagellates producing PST under natural, but not experimental environment.


2011 ◽  
Vol 11 (2) ◽  
pp. 69-79 ◽  
Author(s):  
Ewa Dembowska

Cyanobacterial blooms in shallow lakes of the Iławskie Lake DistrictThe dominance of blue-green algae observed in many lakes is related to a high trophic level. Shallow eutrophic lakes are particularly often abundant in blue-green algae. The research on phytoplankton, the results of which are presented in this paper, was carried out between 2002 and 2005 in six lakes. These lakes differed considerably in their size and management methods applied in the catchment (drainage) area. A few types of water blooms were distinguished, which is related to the catchment area management, the intensity of mixing and the trophic level. Algal blooms of the Planktothrix type appeared in lakes situated in an open area of agricultural catchment basins. Algal blooms of the Limnothrix type were characteristic of lakes with a forest-agricultural catchment area but surrounded by high shores, which reduced the wind influence on the mixing. Sporadic mixed algal blooms were typical of lakes situated in forest catchment areas.


Author(s):  
Aditya R. Nayak ◽  
Malcolm N. McFarland ◽  
Michael S. Twardowski ◽  
James M. Sullivan ◽  
Timothy S. Moore ◽  
...  

2020 ◽  
pp. 65-74
Author(s):  
M. Ramya ◽  
A. Umamaheswari ◽  
S. Elumalai

Water is an absolutely required resource for life nourishment especially for the purpose of drinking, domestic and farming. People in various part of the world are under prodigious threat due to unenviable changes in the physical-chemical and biological properties of an ecosystem. Due to anthropogenic causes like industrialization, the use of fertilizers and urbanization leads to highly polluted water bodies that include fresh and brackish water. These changes influence the harmful growth of cyanobacteria that is blue green algae. cyanoHABs (Cyanobacterial Harmful Algal Blooms)  became a worldwide threat to drinking and recreational purpose due to its adopting nature according to the temperature fluctuations. In this study, a basic introduction to cyanotoxins as well as the entanglement of public health that includes route of exposure health effects and the pervasive impact of cyanotoxins and alleviation efforts in the waterbodies along with that the toxicosis. Cyanobacterial toxins such as hepatotoxicosis, neurotoxicosis, gastrointestinal disturbances respiratory and allergic reactions were reviewed. Their detection process and the treatment techniques with various physicochemical methods and bioassay methods were also reviewed.


2021 ◽  
Vol 9 ◽  
Author(s):  
Samantha L. Sharp ◽  
Alexander L. Forrest ◽  
Keith Bouma-Gregson ◽  
Yufang Jin ◽  
Alicia Cortés ◽  
...  

Harmful algal blooms of cyanobacteria are increasing in magnitude and frequency globally, degrading inland and coastal aquatic ecosystems and adversely affecting public health. Efforts to understand the structure and natural variability of these blooms range from point sampling methods to a wide array of remote sensing tools. This study aims to provide a comprehensive view of cyanobacterial blooms in Clear Lake, California — a shallow, polymictic, naturally eutrophic lake with a long record of episodic cyanobacteria blooms. To understand the spatial heterogeneity and temporal dynamics of cyanobacterial blooms, we evaluated a satellite remote sensing tool for estimating coarse cyanobacteria distribution with coincident, in situ measurements at varying scales and resolutions. The Cyanobacteria Index (CI) remote sensing algorithm was used to estimate cyanobacterial abundance in the top portion of the water column from data acquired from the Ocean and Land Color Instrument (OLCI) sensor on the Sentinel-3a satellite. We collected hyperspectral data from a handheld spectroradiometer; discrete 1 m integrated surface samples for chlorophyll-a and phycocyanin; multispectral imagery from small Unmanned Aerial System (sUAS) flights (∼12 cm resolution); Autonomous Underwater Vehicle (AUV) measurements of chlorophyll-a, turbidity, and colored dissolved organic matter (∼10 cm horizontal spacing, 1 m below the water surface); and meteorological forcing and lake temperature data to provide context to our cyanobacteria measurements. A semivariogram analysis of the high resolution AUV and sUAS data found the Critical Scale of Variability for cyanobacterial blooms to range from 70 to 175 m, which is finer than what is resolvable by the satellite data. We thus observed high spatial variability within each 300 m satellite pixel. Finally, we used the field spectroscopy data to evaluate the accuracy of both the original and revised CI algorithm. We found the revised CI algorithm was not effective in estimating cyanobacterial abundance for our study site. Satellite-based remote sensing tools are vital to researchers and water managers as they provide consistent, high-coverage data at a low cost and sampling effort. The findings of this research support continued development and refinement of remote sensing tools, which are essential for satellite monitoring of harmful algal blooms in lakes and reservoirs.


Author(s):  
Jing Li ◽  
Lars-Anders Hansson ◽  
Kenneth M. Persson

Control of nutrients, mainly nitrogen (N) and phosphorus (P), plays a significant role in preventing cyanobacterial blooms (harmful algal blooms (HABs)). This study aimed at evaluating changes in the risk of the occurrence of cyanobacterial blooms and advancing the understanding of how N and P affect the growth of cyanobacteria in a eutrophic lake, Lake Vombsjön, in southern Sweden. Statistical analysis was used to demonstrate the pattern of cyanobacterial blooms, that the highest content present in September and the later that algal blooms occur, the more likely it is a cyanobacterial bloom as cyanobacteria became dominating in October and November (90%). Two hypothesises tested in Lake Vombsjön confirmed namely that a high total phosphorus (TP) level correlates with an abundance of cyanobacteria and that low N:P ratio (total nitrogen/total phosphorus < 20) favours the growth of cyanobacteria. To control the growth of cyanobacteria in Lake Vombsjön, the TP level should be kept below 20 µg/L and the N:P ratio be maintained at a level of over 20. The two species Planktothrix agardhii, and Pseudanabaena spp. should be carefully monitored especially in late autumn. Future work should consider any high degree of leakage from the sediment of the dissolved phosphorus available there.


Environments ◽  
2019 ◽  
Vol 6 (6) ◽  
pp. 60 ◽  
Author(s):  
Igor Ogashawara

Cyanobacterial harmful algal blooms (CHABs) have been a concern for aquatic systems, especially those used for water supply and recreation. Thus, the monitoring of CHABs is essential for the establishment of water governance policies. Recently, remote sensing has been used as a tool to monitor CHABs worldwide. Remote monitoring of CHABs relies on the optical properties of pigments, especially the phycocyanin (PC) and chlorophyll-a (chl-a). The goal of this study is to evaluate the potential of recent launch the Ocean and Land Color Instrument (OLCI) on-board the Sentinel-3 satellite to identify PC and chl-a. To do this, OLCI images were collected over the Western part of Lake Erie (U.S.A.) during the summer of 2016, 2017, and 2018. When comparing the use of traditional remote sensing algorithms to estimate PC and chl-a, none was able to accurately estimate both pigments. However, when single and band ratios were used to estimate these pigments, stronger correlations were found. These results indicate that spectral band selection should be re-evaluated for the development of new algorithms for OLCI images. Overall, Sentinel 3/OLCI has the potential to be used to identify PC and chl-a. However, algorithm development is needed.


2020 ◽  
Vol 71 (5) ◽  
pp. 636 ◽  
Author(s):  
Elżbieta Wilk-Woźniak

Cyanobacterial harmful algal blooms are known all around the world. Climate change (temperature increase) and human activity (eutrophication) are factors that promote the proliferation of cyanobacteria, leading to the development of blooms and the release of toxins. Abiotic and biotic factors are responsible for the development of blooms and how long they last. Although the abiotic factors controlling blooms are well known, knowledge of biotic factors and their interactions is still lacking. This paper reviews five levels of biotic interactions, namely cyanobacteria–zooplankton, cyanobacteria–ciliates, cyanobacteria–bacteria, cyanobacteria–viruses and cyanobacteria–fungi, showing a more complex food web network than was previously thought. New findings published recently, such as the relationships between cyanobacteria and viruses or cyanobacteria and fungi, indicate that cyanobacterial blooms are not the end of the cycle of events taking place in water habitats, but rather the middle of them. As such, a new approach needs to consider mutual connections, genetic response, horizontal gene transfer and non-linear flow of carbon.


2000 ◽  
Vol 35 (3) ◽  
pp. 489-504 ◽  
Author(s):  
Daniel D. Olding

Abstract An investigation into phytoplankton and periphyton algal communities of two recently constructed Stormwater management ponds suggests that Stormwater impacts on biological communities are reduced during passage through the ponds, providing a degree of protection for biological communities in their receiving waters. In both ponds, disturbance effects from the incoming Stormwater on algal community richness and evenness appear to be greatest in the sediment forebay and are reduced in the main pond. However, the nature of the disturbance in the two systems can be seen to be fundamentally different from a biological perspective, with Rouge Pond functioning primarily to reduce toxins harmful to algal communities (e.g., heavy metals), and Harding Pond acting to reduce nutrients. The taxonomic composition of the two sites provides an indication of the quality of the incoming Stormwater. Rouge Pond, which contains many marine and brackish water species, receives Stormwater runoff from a major highway, while Harding Pond, containing more nutrient rich species, receives Stormwater primarily from residential properties. Despite the nutrient-rich conditions present in both ponds, nuisance blue-green algae (cyanobacte-ria) are conspicuously absent, and the ponds appear to have little potential for developing harmful algal blooms. The lack of blue-green algae can be linked to the hydraulic functioning of the ponds, suggesting that Stormwater facilities may be engineered to inhibit undesirable algal communities.


Dead Zones ◽  
2021 ◽  
pp. 106-123
Author(s):  
David L. Kirchman

As this chapter explains, one approach to evaluate nutrient limitation is to compare nutrient concentrations with the Redfield ratio. Alfred Redfield had no formal background in oceanography, yet he made one of the most fundamental discoveries in the field. He found that the ratio of nitrogen to phosphorus in marine microorganisms is the same as the ratio of the two elements in nutrients dissolved in the oceans. Because of work with the ratio, the current Hypoxia Action Plan for the Gulf of Mexico mentions phosphorus as well as nitrogen. In the Baltic Sea, it was argued that the focus should be solely on phosphorus to limit toxic cyanobacterial blooms, but other work demonstrates the importance of limiting nitrogen for minimizing eutrophication. Once considered to be a dead lake, Lake Erie improved after the construction of wastewater-treatment plants and the banning of phosphorus-rich detergents, as the chapter shows. But the lake continues to have problems with hypoxia and harmful algal blooms, because of continuing inputs of phosphate and organic nitrogen. The chapter ends by arguing that both nitrogen and phosphorus must be considered in efforts to solve the dead-zone problem.


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