scholarly journals Biodegradation of the artificial sweetener saccharin in surface waters and groundwaters

2018 ◽  
pp. 157-165
Author(s):  
Anja Slavič ◽  
Gabriela Kalčikova ◽  
Anita Jemec Kokalj ◽  
Andreja Žgajnar Gotvajn
Keyword(s):  
Laboratory Test ◽  
Surface Waters ◽  
Environmental Conditions ◽  
Natural Waters ◽  
Emerging Pollutants ◽  
Artificial Sweeteners ◽  
Lag Phase ◽  
Artificial Sweetener ◽  
Optimum Conditions ◽  
High Concentrations

The aim of this study was to evaluate the biodegradability of the artificial sweetener saccharin in surface waters and groundwater. Artificial sweeteners are generally persistent under environmental conditions and have been recently classified as emerging pollutants. Biodegradability in three surface waters and one groundwater was tested: the rivers Ljubljanica, Pivka, and Unica, and the groundwater Planina Cave (river Pivka). Under environmentally relevant conditions, saccharin degraded well in hypertrophic water (98%, 14 days) due to high concentrations of phosphorus and nitrogen. There was a longer lag phase and biodegradation time compared to the optimum conditions achieved in the standardized laboratory test. It has been concluded that saccharin is biodegradable in natural waters if said waters contain enough microorganisms and nutrients.

scholarly journals Defluoridation of synthetic and natural waters by polyaluminum chloride-chitosan (PACl-Ch) composite coagulant

2017 ◽  
Vol 18 (1) ◽  
pp. 259-269 ◽  
Author(s):  
Mehrnoosh Abtahi ◽  
Ali Koolivand ◽  
Sina Dobaradaran ◽  
Kamyar Yaghmaeian ◽  
Anoushiravan Mohseni-Bandpei ◽  
...  
Keyword(s):  
Natural Waters ◽  
High Efficiency ◽  
Operating Conditions ◽  
Fluoride Removal ◽  
Optimum Conditions ◽  
Polyaluminum Chloride ◽  
Residual Level ◽  
Wide Range ◽  
High Concentrations ◽  
Composite Coagulant

Abstract Removal of fluoride from drinking water by polyaluminum chloride-chitosan (PACl-Ch) composite coagulant was studied in a batch system. Two types of PACl-Ch coagulant were synthetized as PACl-Ch I and PACl-Ch II with chitosan to aluminum (Ch:Al) weight ratios of 0.5 and 1.0, respectively, and were used for defluoridation under different operating conditions. The composite coagulants were found to be more efficient than both PACl and chitosan. By an increase in the Ch:Al ratio from 0.5 to 1.0, the composite coagulant provided a little more efficiency of fluoride removal and lower residual level of Al. The optimum conditions of pH for fluoride removal by PACl-Ch I and PACl-Ch II were 8.0 and 7.5, respectively. Fluoride removal by the coagulants was not significantly affected by natural organic matter and turbidity, but was declined by high concentrations of common ions. To achieve desirable fluoride levels (lower than 1.0 mg/L) for natural water samples with fluoride levels of 2.0–2.9 mg/L, the required dosage of the composite coagulants were determined to be as low as 3–5 mgAl/L. The PACl-Ch coagulants demonstrated high efficiency for fluoride removal as well as low Al residual level (mainly lower than 0.2 mg/L) in a wide range of operating conditions.

scholarly journals Combating paraben pollution in surface waters with a variety of photocatalyzed systems: Looking for the most efficient technology

2019 ◽  
Vol 17 (1) ◽  
pp. 1317-1327 ◽  
Author(s):  
Joaquin R. Dominguez ◽  
Teresa Gonzalez ◽  
Eduardo M. Cuerda-Correa ◽  
Maria J. Muñoz-Peña
Keyword(s):  
Surface Waters ◽  
Natural Waters ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
Present Report ◽  
Emerging Pollutants ◽  
Fenton Process ◽  
Efficient Technology ◽  
Persistent Contaminants

AbstractThe constant presence of parabens in natural surface waters has raised a growing concern of the potential long-term toxic effects that parabens may have in wildlife, mainly as endocrine disruptors. The present report describes the results of a study in which different photocatalyzed systems, such as photo-Fenton, Fenton, UV-H2O2, UV-TiO2 and UV-TiO2-H2O2, were applied to the removal of these recalcitrant pollutants in some surface waters, including natural (e.g. rivers) and man-made (e.g. reservoirs and wastewater treatment plants). Degradation of four widely-used parabens (methyl-paraben, ethyl-paraben, propyl-paraben and butyl-paraben) was analyzed. Experimental results reveal that the most efficient method to combat these emerging pollutants was photo-Fenton. When this process was optimized, optimal removal efficiency was attained using doses of H2O2 and Fe(II) equal to 2.92·10−4 mol dm-3 and 1.85·10−5 mol dm-3, respectively. It is also worth noting that the removal rate of these contaminants is slower in natural waters. The results suggest that the photo-Fenton process is promising and maybe an adequate technology for the treatment of these persistent contaminants.

scholarly journals Increasing iron concentrations in surface waters – a factor behind brownification?

2011 ◽  
Vol 8 (6) ◽  
pp. 12285-12316 ◽  
Author(s):  
E. S. Kritzberg ◽  
S. M. Ekström
Keyword(s):  
Organic Matter ◽  
Surface Waters ◽  
Natural Waters ◽  
Iron Concentration ◽  
Organic Matter Content ◽  
Matter Content ◽  
Water Color ◽  
The North ◽  
High Concentrations ◽  
Iron Concentrations

Abstract. Browning of inland waters has been noted over large parts of the Northern Hemisphere and is a phenomenon with both ecological and societal consequences. The increase in water color is generally ascribed to increasing amounts of dissolved organic matter of terrestrial origin. However, oftentimes the increase in water color is larger than that of organic matter, implying that changes in the amount of organic matter alone cannot explain the enhanced water color. Water color is known to be affected also by the quality of organic matter and the prevalence of iron. Here we investigated trends in water color, organic matter and iron between 1972 and 2010 in 30 rivers draining into the Swedish cost, and peformed a laboratory iron addition experiment to natural waters, to evaluate the role of iron and organic matter in determining water color. By comparing the effect of iron additions on water color in the experiment, to variation in water color and iron concentration in the monitoring data, we show that iron can explain a significant share of the variation in water color (on average 25%), especially in the rivers in the north of Sweden (up to 74%). Further more, positive trends for iron are seen in 27 of 30 rivers (21–468%) and the increase in iron is larger than that of organic matter, indicating that iron and organic matter concentrations are controlled by similar but not identical processes. We speculate that increasing iron concentrations can be caused by changes in redox conditions, that mean that more anoxic water with high concentrations of soluble FeII are feeding into the surface waters. More studies are needed about why iron is increasing so strongly, since both causes and consequences are partly different from those of increasing organic matter content.

scholarly journals Large subglacial source of mercury from the southwestern margin of the Greenland Ice Sheet

2021 ◽  
Author(s):  
Jon R. Hawkings ◽  
Benjamin S. Linhoff ◽  
Jemma L. Wadham ◽  
Marek Stibal ◽  
Carl H. Lamborg ◽  
...  
Keyword(s):  
Natural Waters ◽  
Inorganic Mercury ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Annual Runoff ◽  
Arctic Ecosystems ◽  
High Mercury ◽  
Southwestern Margin ◽  
High Concentrations ◽  
Dissolved Mercury

AbstractThe Greenland Ice Sheet is currently not accounted for in Arctic mercury budgets, despite large and increasing annual runoff to the ocean and the socio-economic concerns of high mercury levels in Arctic organisms. Here we present concentrations of mercury in meltwaters from three glacial catchments on the southwestern margin of the Greenland Ice Sheet and evaluate the export of mercury to downstream fjords based on samples collected during summer ablation seasons. We show that concentrations of dissolved mercury are among the highest recorded in natural waters and mercury yields from these glacial catchments (521–3,300 mmol km−2 year−1) are two orders of magnitude higher than from Arctic rivers (4–20 mmol km−2 year−1). Fluxes of dissolved mercury from the southwestern region of Greenland are estimated to be globally significant (15.4–212 kmol year−1), accounting for about 10% of the estimated global riverine flux, and include export of bioaccumulating methylmercury (0.31–1.97 kmol year−1). High dissolved mercury concentrations (~20 pM inorganic mercury and ~2 pM methylmercury) were found to persist across salinity gradients of fjords. Mean particulate mercury concentrations were among the highest recorded in the literature (~51,000 pM), and dissolved mercury concentrations in runoff exceed reported surface snow and ice values. These results suggest a geological source of mercury at the ice sheet bed. The high concentrations of mercury and its large export to the downstream fjords have important implications for Arctic ecosystems, highlighting an urgent need to better understand mercury dynamics in ice sheet runoff under global warming.

Bank filtration: a suitable process for the removal of iodinated X-ray contrast media?

2004 ◽  
Vol 50 (5) ◽  
pp. 261-268 ◽  
Author(s):  
S. Schittko ◽  
A. Putschew ◽  
M. Jekel
Keyword(s):  
Drinking Water ◽  
Contrast Media ◽  
Surface Waters ◽  
Sampling Period ◽  
Transformation Products ◽  
Bank Filtration ◽  
Anoxic Conditions ◽  
X Ray ◽  
High Concentrations ◽  
Media Concentration

After bank filtration, effluent influenced surface waters are often used as raw drinking water. It is known that high concentrations of iodinated X-ray contrast media are detectable in such surface waters and thus, more knowledge about the behaviour of the contrast media during bank filtration is necessary and the subject of investigations in this study. The adsorbable organic iodine (AOI), four widely used iodinated X-ray contrast media and four possible transformation products were quantified in an influenced lake, five groundwater wells and a drinking water well. Under anoxic conditions the AOI as well as the concentration of the contrast media are decreased by bank filtration, whereby the AOI is decreased by 64% and the contrast media concentration can be reduced up to 95%, depending on the compound. In the raw drinking water the following average concentrations were determined: Iopromid <20 ng/L, Diatrizote 166 ng/L, Iopamidol 166 ng/L and Iohexol 34 ng/L. Instationary conditions during the sampling period indicate that, at least under anoxic conditions, a large part of the contrast media and transformation products, which are still iodinated, may be associated to colloids and/or humic material.

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.

scholarly journals Ozone damage, detoxification and the role of isoprenoids – new impetus for integrated models

2016 ◽  
Vol 43 (4) ◽  
pp. 324 ◽  
Author(s):  
Supriya Tiwari ◽  
Rüdiger Grote ◽  
Galina Churkina ◽  
Tim Butler
Keyword(s):  
Stomatal Conductance ◽  
Environmental Conditions ◽  
Economic Losses ◽  
Plant Responses ◽  
Damage Scenarios ◽  
Biochemical Processes ◽  
Wide Range ◽  
Defence Responses ◽  
High Concentrations ◽  
The Impact

High concentrations of ozone (O3) can have significant impacts on the health and productivity of agricultural and forest ecosystems, leading to significant economic losses. In order to estimate this impact under a wide range of environmental conditions, the mechanisms of O3 impacts on physiological and biochemical processes have been intensively investigated. This includes the impact on stomatal conductance, the formation of reactive oxygen species and their effects on enzymes and membranes, as well as several induced and constitutive defence responses. This review summarises these processes, discusses their importance for O3 damage scenarios and assesses to which degree this knowledge is currently used in ecosystem models which are applied for impact analyses. We found that even in highly sophisticated models, feedbacks affecting regulation, detoxification capacity and vulnerability are generally not considered. This implies that O3 inflicted alterations in carbon and water balances cannot be sufficiently well described to cover immediate plant responses under changing environmental conditions. Therefore, we suggest conceptual models that link the depicted feedbacks to available process-based descriptions of stomatal conductance, photosynthesis and isoprenoid formation, particularly the linkage to isoprenoid models opens up new options for describing biosphere-atmosphere interactions.

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.

The influence of hydrological pathways on the transport of the herbicide, isoproturon, through an underdrained clay soil

1999 ◽  
Vol 39 (12) ◽  
pp. 77-84 ◽  
Author(s):  
C. M. Heppell ◽  
T. P. Burt ◽  
R. J. Williams ◽  
A. H. Haria
Keyword(s):  
Surface Waters ◽  
Clay Soil ◽  
Quality Standard ◽  
Early Spring ◽  
Hydrological Response ◽  
Macropore Flow ◽  
Ephemeral Stream ◽  
Low Intensity ◽  
Flow Through ◽  
High Concentrations

This paper reports the findings of a 12 month field monitoring programme at Wytham (Oxfordshire, UK), which examined the leaching of the phenylurea herbicide, isoproturon, from an agricultural clay hillslope to the adjacent ephemeral stream. Isoproturon was shown to reach the drains (at 50 cm depth) through a combination of vertical and lateral macropore flow through wormholes and inter-pedal cracks. Seasonal changes in hydrological response were also observed at the site, with lateral flow through inter-pedal cracks providing an important route by which herbicide was transported during autumn and early spring when the clay soils were wetting up. Concentrations of isoproturon in drainflow frequently exceeded the Environment Agency's (EA) non-statutory Environmental Quality Standard (EQS) of 20 μg/l for isoproturon in surface waters. Even under low intensity rainfall (< 1 mm/hr) the saturated region at the base of the hillslope was shown to conduct macropore flow containing significantly high concentrations of herbicide to the drain. The results of this study suggest that those regions close to surface waters which are areas of converging hydrological flow may be key contributors to the problem of isoproturon contamination of surface waters.

scholarly journals Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development

2009 ◽  
Vol 6 (2) ◽  
pp. 3803-3850 ◽  
Author(s):  
E. Breitbarth ◽  
J. Gelting ◽  
J. Walve ◽  
L. J. Hoffmann ◽  
D. R. Turner ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Surface Waters ◽  
Cyanobacterial Bloom ◽  
Euphotic Zone ◽  
Strong Wind ◽  
Ferrous Ions ◽  
The Baltic Sea ◽  
High Concentrations ◽  
Wind Events ◽  
The Baltic

Abstract. Iron chemistry measurements were conducted during summer 2007 at two distinct locations in the Baltic Sea (Gotland Deep and Landsort Deep) to evaluate the role of iron for cyanobacterial bloom development in these estuarine waters. Depth profiles of Fe(II) were measured by chemiluminescent flow injection analysis (CL-FIA) and reveal several origins of Fe(II) to the water column. Photoreduction of Fe(III)-complexes and deposition by rain are main sources of Fe(II) (up to 0.9 nmol L−1) in light penetrated surface waters. Indication for organic Fe(II) complexation resulting in prolonged residence times in oxygenated water was observed. Surface dwelling heterocystous cyanobacteria where mainly responsible for Fe(II) consumption in comparison to other phytoplankton. The significant Fe(II) concentrations in surface waters apparently play a major role in cyanobacterial bloom development in the Baltic Sea and are a major contributor to the Fe requirements of diazotrophs. Second, Fe(II) concentrations up to 1.44 nmol L−1 were observed at water depths below the euphotic zone, but above the oxic anoxic interface. Finally, all Fe(III) is reduced to Fe(II) in anoxic deep water. However, only a fraction thereof is present as ferrous ions (up to 28 nmol L−1) and was detected by the CL-FIA method applied. Despite their high concentrations, it is unlikely that ferrous ions originating from sub-oxic waters could be a temporary source of bioavailable iron to the euphotic zone since mixed layer depths after strong wind events are not deep enough in summer time.

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