In situ redox potential measurements as a monitoring technique for hot spring water quality

Ioka, Seiichiro; Muraoka, Hirofumi; Matsuyama, Kazuo; Tomita, K.

doi:10.1007/s40899-016-0065-4

Cited by 7 publications

(5 citation statements)

References 14 publications

(14 reference statements)

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“…Moreover, this can be implemented long term, continuously, and in situ for large scale applications. Ioka et al (2016) reached the same conclusion in their study when using measured values to monitor hot spring water quality. They used HS − /SO 4 2− and S 2− /SO 4 2− redox couples, because the dominant redox-related species in the hot springs water was sulphur [41].…”

Section: Redox Potential Measurements As a Monitoring Technique For Seo 3 2− Reductionsupporting

confidence: 65%

Performance Evaluation of Selenite (SeO32−) Reduction by Enterococcus spp.

2021

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Lactic acid bacteria (LAB) such as Enterococcus spp. have an advantage over several bacteria because of their ability to easily adapt to extreme conditions which include high temperatures, highly acidic or alkaline conditions and toxic metals. Although many microorganisms have been shown to reduce selenite (SeO32−) to elemental selenium (Se0), not much work has been done on the combined effect of Enterococcus spp. In this study, aerobic batch reduction of different selenite concentrations (1, 3 and 5 mM) was conducted using Enterococcus hermanniensis sp. and Enterococcus gallinarum sp. (3.5 h, 35 ± 2 °C, starting pH > 8.5). Results from the experiments showed that the average reductions rates were 0.608, 1.921 and 3.238 mmol·(L·h)−1, for the 1, 3 and 5 mM SeO32− concentrations respectively. In addition, more selenite was reduced for the 5 mM concentration compared to the 1 and 3 mM concentrations albeit constant biomass being used for all experiments. Other parameters which were monitored were the glucose consumption rate, protein variation, pH and ORP (oxidation reduction potential). TEM analysis was also conducted and it showed the location of electron-dense selenium nanoparticles (SeNPs). From the results obtained in this study, the authors concluded that Enterococcus species’s high adaptability makes it suitable for rapid selenium reduction and biosynthesis of elemental selenium.

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Section: Redox Potential Measurements As a Monitoring Technique For Seo 3 2− Reductionsupporting

confidence: 65%

Performance Evaluation of Selenite (SeO32−) Reduction by Enterococcus spp.

2021

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“…The other factor affecting ORP measurements is the time of result stabilization. Tests conducted by Gómez et al (2006) and Ioka et al (2011Ioka et al ( , 2016 indicate that sometimes the stable values might be observed after at least a week.…”

Section: Essentials Of Oxidation-reduction Potential In Groundwatermentioning

confidence: 96%

Redox potential research in the field of balneochemistry: case study on equilibrium approach to bioactive elements in therapeutic waters

et al. 2020

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In some countries (e.g. Poland, Czechia, Slovakia, Russia, Germany), oxidation-reduction potential (ORP) measurements are required to document the quality of groundwater which are planned to be used as therapeutic waters. ORP is still rarely studied and not fully availed in therapeutic water research. Studies of ORP in various types of therapeutic, mineral and thermal waters in sites of Poland integrated with geochemical equilibrium approach were employed to characterize two redox-sensitive and bioactive elements, i.e. iron and sulphur. Studied waters present reducing conditions (E H between − 406 and − 41 mV) at outflow or extraction sites; however, they significantly differ in terms of total dissolved solids, temperature, and iron, sulphur(II) and sulphate concentrations. These result in recognizable differences, e.g. in terms of saturation state with respect to aquifer rock minerals and the dominating forms of occurrence of elements studied disclosed on the stability field diagrams. Considering the methodological determinants, ORP orchestrated with geochemical modelling tools might be successfully applied for studying natural linkages between various groundwater in natural systems, protecting the therapeutic water resource, and identifying the changes of water quality both at exploitation sites (springs, wells) and treatment places.

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“…Third, low-density microplastics can easily move with the monsoon and be deposited on lakeshore sediments near estuaries. Fourth, human activities are intensive in coastal areas, and the spatial variability of microplastics is mainly influenced by the extent, path, and location of human activities [62]; thus, the abundance of microplastics is relatively great in shallow waters near the coast. In ecosystems, biological uptake is a key aspect of the microplastic transport process, and microplastics in sediments are taken up by a large number of aquatic organisms, including fish [63].…”

Section: Ecological Risk Assessment Of Microplasticsmentioning

confidence: 99%

Distribution Characteristics of Microplastics in Surface Seawater off the Yangtze River Estuary Section and Analysis of Ecological Risk Assessment

Ji,

Yan,

et al. 2023

Toxics

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Microplastics are widespread in the oceans as a new type of pollutant. Due to the special geographical environment characteristics, the Yangtze River estuary region become hotspot for microplastics research. In 2017 and 2019, surface seawater microplastics samples were collected from five stations off the Yangtze River estuary during four seasons (spring, summer, autumn, and winter). The abundance and characteristics of microplastics in seawater were researched. The results showed that microplastics widely existed in surface seawater; the average abundance of microplastics in seawater was (0.17 ± 0.14) items/m3 (0.00561 ± 0.00462) mg/m3; and accounting for 80% of the total plastic debris, the abundance of microplastics was at moderately low levels compared to national and international studies. The particle size of most microplastics was between 1 mm to 2 mm, accounting for 36.1% of the total microplastics. The main shapes of microplastics were fiber, flake, and line, accounting for 39.5%, 28.4%, and 20.8%, respectively. Polypropylene, polyethylene terephthalate, and polyethylene were the main components of microplastics, accounting for 41.0%, 25.1%, and 24.9%, respectively. Yellow, green, black, and transparent were the most common colors, accounting for 21.9%, 19.6%, 16.5%, and 15.7%, respectively. This study shows that the spatial distribution of microplastics in the surface waters off the Yangtze River estuary shows a decreasing trend from nearshore to farshore due to the influence of land-based inputs, hydrodynamics, and human activities; the distribution of microplastics has obvious seasonal changes, and the level of microplastic pollution is higher in summer. The potential ecological risk of microplastics in the surface waters off the Yangtze River estuary is relatively small.

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In situ redox potential measurements as a monitoring technique for hot spring water quality

Cited by 7 publications

References 14 publications

Performance Evaluation of Selenite (SeO32−) Reduction by Enterococcus spp.

Performance Evaluation of Selenite (SeO32−) Reduction by Enterococcus spp.

Redox potential research in the field of balneochemistry: case study on equilibrium approach to bioactive elements in therapeutic waters

Distribution Characteristics of Microplastics in Surface Seawater off the Yangtze River Estuary Section and Analysis of Ecological Risk Assessment

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