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1.
ACS Sens ; 3(7): 1233-1245, 2018 07 27.
Article in English | MEDLINE | ID: mdl-29974739

ABSTRACT

Due to increasing stringency of water legislation and extreme consequences that failure to detect some contaminants in water can involve, there has been a strong interest in developing electrochemical biosensors for algal toxin detection during the past decade, evidenced by literature increasing from 2 journal papers pre-2009 to 24 between 2009 and 2018. In this context, this review has summarized recent progress of successful algal toxin detection in water using electrochemical biosensing techniques. Satisfactory detection recoveries using real environmental water samples and good sensor repeatability and reproducibility have been achieved, along with some excellent limit-of-detection (LOD) reported. Recent electrochemical biosensor literature in algal toxin detection is compared and discussed to cover three major design components: (1) biorecognition elements, (2) electrochemical read-out techniques, and (3) sensor electrodes and signal amplification strategy. The recent development of electrochemical biosensors has provided one more step further toward quick in situ detection of algal toxins in the contamination point of the water source. In the end, we have also critically reviewed the current challenges and research opportunities regarding electrochemical biosensors for algal toxin detection that need to be addressed before they attain commercial viability.


Subject(s)
Bacterial Toxins/analysis , Biosensing Techniques/instrumentation , Cyanobacteria/chemistry , Dinoflagellida/chemistry , Electrochemical Techniques/instrumentation , Marine Toxins/analysis , Microcystins/analysis , Water Pollutants, Chemical/analysis , Water/analysis , Biosensing Techniques/methods , Cyanobacteria Toxins , Electrochemical Techniques/methods , Environmental Monitoring/instrumentation , Environmental Monitoring/methods , Equipment Design , Neurotoxins/analysis , Saxitoxin/analysis
2.
Water Res ; 45(11): 3461-72, 2011 May.
Article in English | MEDLINE | ID: mdl-21529882

ABSTRACT

Granular media filtration was evaluated for the removal of a suite of chemical contaminants that can be found in wastewater. Laboratory- and pilot-scale sand and granular activated carbon (GAC) filters were trialled for their ability to remove atrazine, estrone (E1), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR) and N-nitrosodiethylamine (NDEA). In general, sand filtration was ineffective in removing the contaminants from a tertiary treated wastewater, with the exception of E1 and EE2, where efficient removals were observed after approximately 150 d. Batch degradation experiments confirmed that the removal of E1 was through biological activity, with a pseudo-first-order degradation rate constant of 7.4 × 10(-3) h(-1). GAC filtration was initially able to effectively remove all contaminants; although removals decreased over time due to competition with other organics present in the water. The only exception was atrazine where removal remained consistently high throughout the experiment. Previously unreported differences were observed in the adsorption of the three nitrosamines, with the ease of removal following the trend, NDEA > NMOR > NDMA, consistent with their hydrophobic character. In most instances the removals from the pilot-scale filters were generally in agreement with the laboratory-scale filter, suggesting that there is potential in using laboratory-scale filters as monitoring tools to evaluate the performance of pilot- and possibly full-scale sand and GAC filters at wastewater treatment plants.


Subject(s)
Endocrine Disruptors/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/chemistry , Atrazine/analysis , Atrazine/chemistry , Biodegradation, Environmental , Charcoal/analysis , Charcoal/chemistry , Diethylnitrosamine/analysis , Diethylnitrosamine/chemistry , Dimethylnitrosamine/analysis , Dimethylnitrosamine/chemistry , Endocrine Disruptors/analysis , Estrone/analysis , Estrone/chemistry , Ethinyl Estradiol/analysis , Ethinyl Estradiol/chemistry , Filtration , Nitrosamines/analysis , Nitrosamines/chemistry , Waste Disposal, Fluid/instrumentation , Water Pollutants, Chemical/analysis
3.
J Hazard Mater ; 188(1-3): 288-95, 2011 Apr 15.
Article in English | MEDLINE | ID: mdl-21339048

ABSTRACT

Cyanobacterial metabolites, both toxic and non-toxic, are a major problem for the water industry. Nanofiltration (NF) may be an effective treatment option for removing organic micropollutants, such as cyanobacterial metabolites, from drinking water due to its size exclusion properties. A rapid bench scale membrane test (RBSMT) unit was utilised to trial four NF membranes to remove the cyanobacterial metabolites, microcystin, cylindrospermopsin (CYN), 2-methylisoborneol (MIB) and geosmin (GSM) in two treated waters sourced from the Palmer and Myponga water treatment plants. Membrane fouling was observed for both treated waters; however, only minor differences were observed between feed waters of differing natural organic matter (NOM) concentration. Low molecular weight cut-off (MWCO), or 'tight' NF, membranes afforded average removals above 90% for CYN, while removal by higher MWCO, or 'loose' NF membranes was lower. MIB and GSM were removed effectively (above 75%) by tight NF but less effectively by loose NF. Microcystin variants (MCRR, MCYR, MCLR, MCLA) were removed to above 90% by tight NF membranes; however, removal using loose NF membranes depended on the hydrophobicity and charge of the variant. Different NOM concentration in the treated waters had no effect on the removal of cyanobacterial metabolites.


Subject(s)
Cyanobacteria/metabolism , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Filtration , Membranes, Artificial
4.
J Hazard Mater ; 186(2-3): 1553-9, 2011 Feb 28.
Article in English | MEDLINE | ID: mdl-21227576

ABSTRACT

Cyanobacteria are a major problem for the world wide water industry as they can produce metabolites toxic to humans in addition to taste and odour compounds that make drinking water aesthetically displeasing. Removal of cyanobacterial toxins from drinking water is important to avoid serious illness in consumers. This objective can be confidently achieved through the application of the multiple barrier approach to drinking water quality and safety. In this study the use of a multiple barrier approach incorporating coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of intracellular and extracellular cyanobacterial toxins from two naturally occurring blooms in South Australia. Also investigated was the impact of these treatments on the UF flux. In this multibarrier approach, coagulation was used to remove the cells and thus the intracellular toxin while PAC was used for extracellular toxin adsorption and finally the UF was used for floc, PAC and cell removal. Cyanobacterial cells were completely removed using the UF membrane alone and when used in conjunction with coagulation. Extracellular toxins were removed to varying degrees by PAC addition. UF flux deteriorated dramatically during a trial with a very high cell concentration; however, the flux was improved by coagulation and PAC addition.


Subject(s)
Bacterial Toxins/isolation & purification , Charcoal/chemistry , Cyanobacteria/chemistry , Eutrophication , Marine Toxins/isolation & purification , Microcystins/isolation & purification , Anabaena/growth & development , Anabaena/physiology , Australia , Carbon/analysis , Cell Count , Cyanobacteria/growth & development , Cyanobacteria Toxins , Enzyme-Linked Immunosorbent Assay , Fresh Water/analysis , Membranes, Artificial , Microcystins/analysis , Microcystis/chemistry , Microcystis/growth & development , Molecular Weight , Polyvinyls/chemistry , Saxitoxin/analysis , Saxitoxin/isolation & purification , Spectrophotometry, Ultraviolet , Ultrafiltration , Water Purification/methods
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