Biodegradation studies as an important way to estimate the environmental fate of chemicals

1999 ◽  
Vol 39 (10-11) ◽  
pp. 375-382
Author(s):  
Andreja Žgajnar Gotvajn ◽  
Jana Zagorc-Končan
Keyword(s):  
Surface Waters ◽  
Natural Waters ◽  
Environmental Fate ◽  
Standard Test ◽  
Screening Tests ◽  
Natural Systems ◽  
Additional Information ◽  
Assessment Tests ◽  
Ready Biodegradability ◽  
Biodegradability Assessment

Biodegradation is confirmed as an important mechanism of organic chemicals removal in natural systems. Estimation of biodegradability of chemicals which reach the aquatic environment in significant or even negligible quantities is necessary in assessing the entire hazard associated with their use. The aim of our study was to compare the standardized ready biodegradability assessment test (closed bottle test) and its modifications, employing the basic agreements on test principles of simulation of biodegradation in surface waters, yet no official standard method has been adopted. The standard test was modified using various natural river waters and a variety of nutrient conditions and microbial species trying to simulate the natural environment in the simplified way. Tests were performed with two compounds with different ability to degrade. Experiments indicate that predictability of biodegradation obtained by ready biodegradability assessment tests for surface waters in many cases is not reliable, because of different conditions, which may prevail in surface waters over time and affect biodegradation. However, the use of natural waters in screening tests assures additional information on fate of chemicals in rivers and lakes.

Comparison of biodegradability assessment tests for chemical substances in water

1996 ◽  
Vol 33 (6) ◽  
pp. 207-212 ◽  
Author(s):  
Andreja Žgajnar Gotvajn ◽  
Jana Zagorc-Koncan
Keyword(s):  
Lag Phase ◽  
Test Results ◽  
The European Union ◽  
Test Compound ◽  
Biodegradation Rate ◽  
Chemical Substances ◽  
Assessment Tests ◽  
Ready Biodegradability ◽  
Biodegradation Testing ◽  
Biodegradability Assessment

Assessment of biodegradability of specified compounds or wastewaters is an important guide to estimate their behavior in natural aquatic environment. Multilevel protocol for biodegradability assessment was proposed in the European Union to unify tests in different European countries. The protocol begins with tests for ready biodegradability, which are follosed by inherent biodegradability tests and the multilevel protocol is completed with simulation tests. The three-level tests are differentiated by procedure, concentration of test compound, amount and source of inoculum used. The comparisons of biodegradability tests, one standardized from zero level and one standardized from level one and their non-standardized modifications were made for different test substances to estimate the differences between them and to estimate the meaning of multilevel biodegradability testing. It was pointed out that, due to various biodegradation testing levels, differences between test results occur. The main ones are: the lag phase, the biodegradation rate and the final level of biodegradation.

Dynamic features of speciation analysis by adsorptive stripping techniques

2010 ◽  
Vol 7 (3) ◽  
pp. 242 ◽  
Author(s):  
Raewyn M. Town ◽  
Herman P. van Leeuwen
Keyword(s):  
Ligand Exchange ◽  
Natural Waters ◽  
Environmental Fate ◽  
Metal Speciation ◽  
Speciation Analysis ◽  
Dynamic Features ◽  
Natural Systems ◽  
Surface Active ◽  
The Stability ◽  
Kinetic Features

Environmental context.The environmental fate and bioavailability of metal ions in natural waters is determined by their thermodynamic stability and kinetic features, both of which are distributed. Competing ligand exchange – adsorptive stripping (CLE-AdS) is a technique that measures a certain portion of these complexes as determined by the stability of the selected competing ligand and the dynamic features of the sample complexes that remain following ligand exchange. Exploitation of CLE-AdS to determine a spectrum of sample complexes requires insight into its thermodynamic and kinetic windows. Abstract.The kinetic features of the accumulation step of competing ligand exchange – adsorptive stripping (CLE-AdS) in metal speciation methodology are elaborated. During the adsorptive accumulation process, the flux of the surface active complex MLad towards the electrode may be modified by the coupled conversions of ML and M into MLad. An immediate consequence is that the accumulation flux of MLad can be greater than that corresponding to its mere bulk concentration: a labile ML contributes fully to the MLad accumulation, and a further flux enhancement can arise if ML is more mobile than MLad (DML > DMLad). Applying the conventional lability criterion, we present a framework for interpretation of CLE-AdS measurements in the presence of kinetic contributions from sample ML to the adsorptive accumulation of MLad. Measured accumulation fluxes for a kinetic case are well described by the presented theoretical framework. The dynamic analysis provides the basis for exploitation of CLE-AdS over a wider kinetic window than has been used to date. Consideration of the dynamics of sample species during the adsorptive accumulation step is fundamental for interpretation of metal speciation by CLE-AdS in complex natural systems that contain a distribution of complexes of different stability, lability, and mobility.

Effect of UVB Irradiation on Cu2+-Binding Organic Ligands and Cu2+ Speciation in Alpine Lake Waters of New Zealand

2005 ◽  
Vol 2 (1) ◽  
pp. 56 ◽  
Author(s):  
Sylvia Sander ◽  
Jonathan P. Kim ◽  
Barry Anderson ◽  
Keith A. Hunter
Keyword(s):  
New Zealand ◽  
Surface Waters ◽  
Natural Waters ◽  
Austral Summer ◽  
Organic Ligands ◽  
Conditional Stability ◽  
Uvb Radiation ◽  
Dissolved Metals ◽  
Conditional Stability Constant ◽  
Uvb Irradiation

Environmental Context. The bioavailability of dissolved metals in natural waters is directly affected by metal-sequestering agents. These agents include soil-derived matter and compounds released by microorganisms, since copper can support or inhibit aquatic microorganisms depending on concentration. During summer the levels of copper increase in surface waters, an effect intuitively attributable to increased ultraviolet light degrading the sequestering agents more effectively, leading to a concurrent release of the metal. This paper shows that the amount of degradation attributable to light is too low to explain the metal release and that a biological influence may instead be responsible. Abstract. The influence of UVB irradiation on the Cu2+ binding by natural organic ligands in six alpine lakes on the South Island, New Zealand, has been investigated using competitive ligand equilibration with salicylaldoxime and detection by cathodic stripping voltammetry (CLE-CSV). During austral summer 2002–2003 the total dissolved Cu ([Cu]T), the concentration of strong Cu2+-binding ligands ([L]T), and their conditional stability constant K´´ were determined in surface samples of all six lakes. All lakes exhibited appreciable concentrations of a strong Cu2+ binding ligand with similar K´´ values and concentrations always exceeding [CuT], thus dominating Cu2+ speciation. Four lakes (Hayes, Manapouri, Wanaka, Te Anau) showed no appreciable trend in [LT] throughout the summer, whereas in Lakes Wakatipu and Hawea [LT] increased steadily throughout this period. Laboratory UVB irradiation of lake water samples using a 400 W mercury lamp with a Pyrex glass filter (λ > 280 nm) showed that Cu2+-binding ligands are destroyed by UVB radiation, causing [L]T to decrease with a rate of –0.588 nmol L–1 h–1 (r2 0.88). From this we calculate that the in situ ligand destruction rate by UVB in summer for surface waters of these lakes is too small to significantly affect [LT], and conclude that variations in ligand concentrations must result from seasonally variable biological factors.

Interferences With Urine Drug Screens

2010 ◽  
Vol 24 (1) ◽  
pp. 102-108 ◽  
Author(s):  
Charles Herring ◽  
Andrew J. Muzyk ◽  
Cynthia Johnston
Keyword(s):  
Screening Tests ◽  
Test Results ◽  
Appropriate Use ◽  
Additional Information ◽  
Concurrent Use ◽  
Nonmalignant Pain ◽  
Urine Drug ◽  
Drug Assays ◽  
Chronic Nonmalignant Pain ◽  
Urine Drug Screening

Qualitative urine drug assays are frequently used in conjunction with opioid contracts as a means of monitoring use of prescribed controlled substances as well as concurrent use of illicit substances in patients receiving opioids for chronic nonmalignant pain (CNMP) management. Appropriate use of these screening tests, in conjunction with opioid contracts, may provide the health care provider with additional information needed to safely prescribe opioids for selected individuals with CNMP. It is important for the practitioner caring for patients subject to random urine drug screening to understand interferences with the commonly used urine drug assays, as well as knowing options to confirm contested test results. We reviewed the literature on urine drug assay test interferences and present a summary of this information in this article.

Anomalously low electrostatic bending stiffness of graphene oxide 2D membranes regulates its environmental fate in aquatic ecosystems

2021 ◽  
Author(s):  
Mohamad Ali Sanjari Shahrezaei ◽  
Seyed Mohammad-Reza Taheri ◽  
Hesam Nikfazan ◽  
Alexandra Satalov ◽  
Mohsen Moazzami Gudarzi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Environmental Impact ◽  
Surface Waters ◽  
Aquatic Ecosystems ◽  
Environmental Fate ◽  
2D Materials ◽  
Bending Stiffness ◽  
High Importance

Though deemed to be of high importance for the determination of environmental impact of 2D materials upon their release into surface waters, control over the conformational engineering of atomically thin...

scholarly journals Geochemistry of natural waters of the Baydar valley (Crimean Peninsula)

2019 ◽  
Vol 98 ◽  
pp. 01036
Author(s):  
Larisa A. Nichkova ◽  
Dmitry A. Novikov ◽  
Anatoliy V. Chernykh ◽  
Fedor F. Dultsev ◽  
Galina A. Sigora ◽  
...  
Keyword(s):  
Trace Elements ◽  
Surface Waters ◽  
Natural Waters ◽  
Upper Jurassic ◽  
Alkaline Ph ◽  
Crimean Peninsula ◽  
Ph Values ◽  
Ree Distribution ◽  
Basic Characteristics ◽  
The Crimean Peninsula

The paper discusses the pioneering results of comprehensive hydrogeochemical studies of natural waters of the Baydar valley (southwestern parts of the Crimean Peninsula), whose major aquifers are confined to the upper Jurassic sediments (karst limestone) representing the most important hydrogeological feature of the study area. Fresh and ultra-fresh waters of predominantly bicarbonate calcium composition with total mineralization in the range from 194 to 1137 mg/dm3 are most widespread in the region. The analyzed waters (surface, ground and artesian) differ significantly in chemical composition and their basic characteristics have been arranged in the following patterns: mineralization of 254-832 mg/dm3 and neutral pH (6.98-7.54) for artesian waters; higher mineralization level (up to 1137 mg/dm3) and wide variations of pH values (from 7.18 to 8.31) for ground waters; mineralization from 194 to 288 mg/dm3 and a slightly alkaline pH (between 8.02 and 8.04) for surface waters collected in the Chyornaya river basin and Chernorechensk reservoir. The studied waters display a unique spectrum of trace elements and REE distribution.

scholarly journals Semiarid climate and hyposaline lake on early Mars inferred from reconstructed water chemistry at Gale

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Keisuke Fukushi ◽  
Yasuhito Sekine ◽  
Hiroshi Sakuma ◽  
Koki Morida ◽  
Robin Wordsworth
Keyword(s):  
Pore Water ◽  
Surface Waters ◽  
Natural Waters ◽  
Lacustrine Sediments ◽  
Redox States ◽  
Gale Crater ◽  
Fundamental Properties ◽  
Formation Conditions ◽  
Early Mars ◽  
Multiple Scenarios

Abstract Salinity, pH, and redox states are fundamental properties that characterize natural waters. These properties of surface waters on early Mars reflect palaeoenvironments, and thus provide clues on the palaeoclimate and habitability. Here we constrain these properties of pore water within lacustrine sediments of Gale Crater, Mars, using smectite interlayer compositions. Regardless of formation conditions of smectite, the pore water that last interacted with the sediments was of Na-Cl type with mild salinity (~0.1–0.5 mol/kg) and circumneutral pH. To interpret this, multiple scenarios for post-depositional alterations are considered. The estimated Na-Cl concentrations would reflect hyposaline, early lakes developed in 104–106-year-long semiarid climates. Assuming that post-depositional sulfate-rich fluids interacted with the sediments, the redox disequilibria in secondary minerals suggest infiltration of oxidizing fluids into reducing sediments. Assuming no interactions, the redox disequilibria could have been generated by interactions of upwelling groundwater with oxidized sediments in early post-depositional stages.

scholarly journals Simultaneous Removal of Arsenate and Chromate from Ground- and Surface- Waters by Iron-Based Redox Assisted Coagulation

2020 ◽  
Vol 12 (13) ◽  
pp. 5394
Author(s):  
Asterios Laskaridis ◽  
Ioannis Sarakatsianos ◽  
Nikolaos Tzollas ◽  
Ioannis A. Katsoyiannis
Keyword(s):  
Drinking Water ◽  
Surface Waters ◽  
Natural Waters ◽  
Iron Concentration ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Matrix Composition ◽  
Ph Values ◽  
Water Matrix ◽  
Iron Based

Arsenic (As) and chromate (Cr(VI)) contamination of ground and surface waters is a major problem worldwide. Given that a new drinking water limit is anticipated for Cr(VI) and that the limit of arsenic in drinking water is quite low (10 μg/L), there is an urgent need for evaluating technologies that could be efficient for removal of both contaminants simultaneously. In this work, the use of Fe(II) redox assisted coagulation was investigated to simultaneously remove the contaminants of interest. The basic principle of this technology is that Fe(II) could react with Cr(VI) and form Fe(III)-hydroxides and insoluble Cr(III) species, while the freshly formed Fe(III) hydroxides are very efficient adsorbents for As(V). The effect of pH, the water matrix composition, Fe(II) dose, initial contaminant concentrations, NOM presence and phosphate concentration were the examined parameters. The results revealed that with a dose of 2 mg/L Fe(II), residual As(V) and Cr(VI) concentrations were both below 10 μg/L, from initial concentrations of 50 μg/L. Though, this is effective only at circumneutral pH values. This is however not a big obstacle, since most natural waters, especially groundwaters, have near neutral pH values. At these pH values, residual iron concentration was far below 200 μg/L. The presence of phosphate anions inhibited As(V) removal but had no effect on Cr(VI) removal. Increasing Fe(II) concentrations eliminated the effect of phosphate and provided simultaneous phosphate removal. Therefore, Fe(II) coagulation can be applied, with secured results, for simultaneous As(V), Cr(VI) and phosphate removal from waters.

scholarly journals Distribution of the stable isotopes (δ18O, δD и δ13C) in natural waters of the Baydar valley (Crimean Peninsula)

2019 ◽  
Vol 98 ◽  
pp. 01038
Author(s):  
Dmitry A. Novikov ◽  
Larisa A. Nichkova ◽  
Anatoliy V. Chernykh ◽  
Fedor F. Dultsev ◽  
Alexander N. Pyryaev ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Organic Compounds ◽  
Surface Waters ◽  
Atmospheric Carbon Dioxide ◽  
Natural Waters ◽  
Meteoric Water ◽  
Soil Layer ◽  
Study Region ◽  
Crimean Peninsula ◽  
The Crimean Peninsula

Results of the study of the stable isotopes (δ18O, δD and δ13C) distribution in natural waters of the Baydar valley (southwestern part of the Crimean Peninsula) are presented. The study region holds fresh and ultra-fresh waters of predominantly bicarbonate calcium composition with TDS varying from 194 to 1137 mg/dm3. The research results revealed that all of the studied waters are of atmospheric origin that lie either along the global (GMWL) or local (LMWL) meteoric water lines. The established variations are: from -9.5 to -5.6‰ for δ18O values in waters with δD values varying from -64.0 to -40.0‰. The source for bicarbonate ion enriched in δ13C in natural waters of the Bauydar valley are carbonate sedimentary rocks, atmospheric carbon dioxide and organic compounds. Surface waters have heavier isotopic composition δ13C (-9.2 – -7.0‰) because of the atmospheric CO2. Artesian waters are differentiated by lighter δ13C (-12.8 – -10.7‰) due to the interactions between carbonate rocks and the dispersed organic matter. Water sources (springs, wells) are characterized by the widest variations of δ13C (-6.9 – -15.5‰) due to the presence of the atmospheric CO2 and intense processes of biochemical decomposition of organic compounds in the soil layer.

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