Estimation of stochastic colored noise signal driving DNAPLs degradation kinetics in the natural water environment

Chemosphere ◽  
2015 ◽  
Vol 119 ◽  
pp. 130-136 ◽  
Author(s):  
L. He ◽  
H. Lu
Keyword(s):  
Natural Water ◽  
Colored Noise ◽  
Degradation Kinetics ◽  
Water Environment ◽  
Noise Signal

scholarly journals Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen

2020 ◽  
Author(s):  
Katja Pulkkinen ◽  
Tarmo Ketola ◽  
Jouni Laakso ◽  
Johanna Mappes ◽  
Lotta-Riina Sundberg
Keyword(s):  
Growth Rate ◽  
Natural Water ◽  
Phenotypic Variation ◽  
Water Environment ◽  
High Growth ◽  
Flavobacterium Columnare ◽  
Bacterial Survival ◽  
Fish Pathogen ◽  
Fish Farms ◽  
Host Environment

SummaryPhenotypic variation allows adaptation of opportunistic pathogens to variable conditions in the outside-host environment with strong effects on their epidemiology and pathogenicity in hosts. Here we found that the isolates of an opportunistic fish pathogen Flavobacterium columnare from fish farming environment had higher phenotypic variation between two morphotypes in growth, as compared to the isolates from the natural water environment. The rough morphotypes had higher growth rate than the rhizoid morphotypes especially in the higher resource concentrations and in the higher temperature, but only if the isolate was originating from the fish farms. Rhizoid morphotype was more virulent than the rough type regardless of their origin. However, the virulence of the rough type increased sharply with the size of the fish, and the bacterial isolates from the gills of diseased fish were rhizoid type, indicating a reversal of the rough morphotype into rhizoid in contact with the fish. The high growth rate of the rough morphotype combined with the morphotype reversibility could increase the probability of columnaris epidemics at fish farms. Our findings suggest that intensive farming imposes different selection pressures on bacterial survival in the outside-host environment and its transmission compared to the natural water environment.

Degradation kinetics and mechanism of 3-Chlorobenzoic acid in anoxic water environment using graphene/TiO2 as photocatalyst

2018 ◽  
Vol 41 (17) ◽  
pp. 2165-2179 ◽  
Author(s):  
Yiyang Huang ◽  
Hui Wang ◽  
Kai Huang ◽  
Donggen Huang ◽  
Shuang Yin ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Water Environment ◽  
Kinetics And Mechanism ◽  
Chlorobenzoic Acid ◽  
Anoxic Water

The Critical Condition for the Initiation of Localized Corrosion of Mild Steels in Contact with Bentonite Used For Nuclear Waste Package

1991 ◽  
Vol 257 ◽  
Author(s):  
Guen Nakayama ◽  
Masatsune Akashi
Keyword(s):  
Mild Steel ◽  
Nuclear Waste ◽  
Pitting Corrosion ◽  
Natural Water ◽  
Crevice Corrosion ◽  
Water Environment ◽  
Underground Water ◽  
Localized Corrosion ◽  
Critical Conditions ◽  
General Corrosion

ABSTRACTIt has been established that the mild steels which undergo the general corrosion in the acidic to neutral environments, attain the passivity status in alkaline environments, thereby becoming liable to the localized corrosion, such as pitting corrosion and crevice corrosion. Now, for the case of using bentonite as a buffer to stand between the hostrock and the geological disposal packages of high level nuclear waste, localized corrosion behaviors of mild steel as a candidate for such a package has been studied quantitatively for environments where the the otherwise neutral ground water would be turned slightly alkaline with pH = 9.5 - 10.0.In view of the lack of quantitative data on the passivity-to-localized corrosion of mild steel in natural water environments of weak alkalinity, the present authors have previously determined an empirical E-pH diagram for mild steel with a 20 °C, 1 m mol/L [HC03-], 10 ppm [CI -] solution simulating the natural water environment concerned; it has been shown that the general corrosion-to-passivity transition condition was determined to be pHd =9.4, and the mild steel was shown to be liable to localized corrosion over a large portion of the passivity domain. The present paper discusses behaviors, mechanisms, and critical conditions for initiation of localized corrosion in mild steel placed in bentonitesuspending natural water environment, in terms of the critical potentials for pitting (Vc), and crevice corrosion (ER,CREV). Bentonite was addid to the solution in varying amounts to give bentonite-to-solution ratios up to 0.1, while the pHvalue was adjusted appropriately with sodium carbonate, always keeping the bentonite particles in suspension.It is demonstrated that bentonite particles suspended in water will deposit upon the steel on receipt of Fe2 + ions, thereby promoting pitting corrosion by preventing repassivation and promoting crevice corrosion by acting as an effective crevice, once the environment conditions become favorable for localized corrosion.We conclude therefore that disposal package made of mild steel and placed in an underground water environment with bentonite as buffer will be liable to localized corrosion.

Purging a Muddy–Earthy Flavor Taint from Rainbow Trout (Salmo gairdneri) by Transferring to Artificial and Natural Holding Environments

1976 ◽  
Vol 33 (1) ◽  
pp. 160-166 ◽  
Author(s):  
D. G. Iredale ◽  
R. K. York
Keyword(s):  
Rainbow Trout ◽  
Natural Water ◽  
Water Environment ◽  
Salmo Gairdneri ◽  
Clear Water ◽  
Threshold Levels ◽  
Sensory Data ◽  
Time Required ◽  
Artificial Water

Studies were conducted to determine the length of time required to purge a muddy–earthy flavor taint from pond cultured rainbow trout (Salmo gairdneri) transferred to two different clear water environments. Sensory data from trained judges show that this required 5 days for fish transferred to a rapidly changing purified artificial water environment and 16 days for fish transferred to a relatively static natural water environment to reduce this taint to or below threshold levels of recognition.

scholarly journals Восстановление сообществ водных беспозвоночных в результате очистки донных отложений от нефти

2017 ◽  
Vol 7 (4) ◽  
pp. 407-413
Author(s):  
Yu. A. Noskov ◽  
D. S. Vorobiev
Keyword(s):  
Species Diversity ◽  
Bottom Sediments ◽  
Natural Water ◽  
Oil Spills ◽  
Water Environment ◽  
Water Bodies ◽  
Time Interval ◽  
Ecological Groups ◽  
Oil Concentration ◽  
Natural Water Bodies

Oil decontamination of water bodies is one of the most complex and time-consuming tasks in the field of liquidation of oil spills. The complexity of cleaning natural water bodies is associated with a dynamic water environment and a variety of oil transformation processes that occur in the water. The most advanced and developed are technologies and methods of collecting oil and oil products from the surface of water bodies. Economically acceptable and well-grounded technologies for oil decontamination of bottom sediments are presented in minimal quantities, and often are not applicable to natural water bodies. The technology for oil decontamination based on flotation has been developed and successfully applied on Lake Shchuch'ye in 2004–2005 and showed a positive result after two summer seasons of work. This article presents the results of aquatic ecosystems recoverу as a result of oil decontamination of bottom sediments. The issue of restoration of the aquatic ecosystem as a result of cleaning bottom sediments from oil after a considerable time interval has been studied. A comparison of the quantitative indices and species diversity of the zooplankton of Shchuch'ye Lake from 2004 to 2016 showed a clear tendency of increasing the abundance, biomass and species diversity of total zooplankton and Cladocera in particular. In 2016 the amount of zooplankton species of Shchuch’ye Lake reaches the number of species of the uncontaminated lake, using as a control. It was shown that the macrozoobenthic fauna of Shchuch'ye Lake is poorer in both the number of main ecological groups and in species diversity within certain groups characteristic than in the uncontaminated lake. Some groups were found in both lakes, but the species diversity of Lake Shchuchye was poorer. The exception was a group of leeches, which had a greater variety in Lake Shchuch'ye. The change in the oligochaetene complex to chironomid, both in numbers and in biomass, indicates an improvement in environmental conditions, since chironomids are more sensitive to the quality of the habitat. Chemical analysis of bottom sediments in 2016 revealed that the oil concentration did not exceed 0.9 mg / kg, which indicates the effectiveness of the oil decontamination technology of bottom sediments.

Sign in / Sign up

Export Citation Format

Share Document