Sonochemical degradation of neonicotinoid pesticides in natural surface waters. Influence of operational and environmental conditions

2021 ◽  
Vol 197 ◽  
pp. 111021
Author(s):  
Joaquin R. Domínguez ◽  
Teresa González ◽  
Sergio Correia ◽  
Eva M. Domínguez
Keyword(s):  
Surface Waters ◽  
Environmental Conditions ◽  
Natural Surface ◽  
Neonicotinoid Pesticides

Modeling seasonal variability of fecal coliform in natural surface waters using the modified SWAT

2016 ◽  
Vol 535 ◽  
pp. 377-385 ◽  
Author(s):  
Kyung Hwa Cho ◽  
Yakov A. Pachepsky ◽  
Minjeong Kim ◽  
JongCheol Pyo ◽  
Mi-Hyun Park ◽  
...  
Keyword(s):  
Surface Waters ◽  
Seasonal Variability ◽  
Fecal Coliform ◽  
Natural Surface

Particles in Natural Surface Waters: Chemical Composition and Size Distribution

2000 ◽  
Vol 77 (1) ◽  
pp. 75-93 ◽  
Author(s):  
Susan E.J. Buykx ◽  
Marc A.G.T. Van Den Hoop ◽  
Rob F.M.J. Cleven ◽  
Jacques Buffle ◽  
Kevin J. Wilkinson
Keyword(s):  
Chemical Composition ◽  
Size Distribution ◽  
Surface Waters ◽  
Natural Surface

scholarly journals ENVIRONMENTAL CONDITIONS OF THE WATERS OF THE MANZANARES RIVER, CUMANA-SUCRE, VENEZUELA

2016 ◽  
Author(s):  
Arístide Márquez ◽  
William James Senior ◽  
Gregorio Martínez ◽  
J. Castañeda
Keyword(s):  
Heavy Metals ◽  
Dissolved Oxygen ◽  
Surface Waters ◽  
Environmental Conditions ◽  
Dilution Effect ◽  
Volume Flow ◽  
Human Consumption ◽  
Suspended Material ◽  
Low Salinity ◽  
Total Ammonium

The Manzanares River is one of the more important rivers of Venezuela inasmuch as it is used to supply drinkingwater to a large part of the northeastern zone of Venezuela. For this reason a study was undertaken of the surface waters of theestuarine zone of the river, following the saline gradient from zero to salinities greater than 30. The following properties weremeasured: river volume flow, rainfall, pH, temperature, suspended materials, dissolved oxygen and ammonium, and heavy metals(Fe, Mn, Cu, Zn, Ni, Cr, Pb and Cd) in particulate and dissolved phases. River volume flow varied with seasonal rainfall throughoutthe year, as expected, while temperature varied between 24.5 and30.4 oC and pH ranged from 6.65 and 8.9. From the dry to the wetseason, suspended material increased from 23 to 880 mg/l at low salinity, and always decreased progressively as salinity increased.Concentrations of total ammonium, 14.5 to 14.3 mmol/l, were high, while those of dissolved oxygen, 3.57 to 5.27 ml/l, were low, andthese levels were even more accentuated at salinities under 5 during the dry season. The highest concentrations found for heavymetals were: Fe 406.02; Mn 5.57; Zn 2.18; Cu 0.72; Cr 0.19; Ni 0.72; Pb 0.12; Cd 0.03 mmol/l. These surpass Venezuelan legal limitsfor water intended for human consumption as well as for waters to be discharged in coastal areas. Concentrations decreased atincreased salinity because of the dilution effect, flocculation and/or precipitation in the form of oxyhydroxides. The results obtainedin this study reveal a serious deterioration of the state of the waters of the lower Manzanares river.

scholarly journals Critical multi-stranded approach for determining the ecological values of diatoms in unique aquatic ecosystems of anthropogenic origin

2019 ◽  
Author(s):  
Rafał M. Olszyński ◽  
Ewelina Szczepocka ◽  
Joanna Żelazna-Wieczorek
Keyword(s):  
Surface Waters ◽  
Environmental Conditions ◽  
Aquatic Ecosystems ◽  
Ecological Indicator ◽  
Indicator Values ◽  
Chemical Parameters ◽  
Physical And Chemical Parameters ◽  
Characteristic Species ◽  
Physical And Chemical ◽  
Ecological Indicator Values

Background. The ecological state of surface waters is typically assessed by a multi-aspect approach based on a determination of its chemical and physical parameters, by hydromorphology and the use of indicator organisms such as benthic diatoms. By assigning ecological indicator values, it is possible to create diatom indices which serve as the basic tool in assessing the ecological status of surface waters. These ecological indicator values are set according to classification systems, such as the Van Dam et al. 1994 system, which classifies species of diatoms according to seven different ecological factors. However, recent studies on the autecology of diatoms have shown the need to verify and establish new ecological indicator values. To this end, aquatic ecosystems are good environments to observe the range of tolerance of benthic diatoms to environmental conditions due to their unique physical and chemical parameters. The aim of the present study was to propose the establishment of new, or altered, ecological indicator values, according to Van Dam et al. classification, of species of diatoms characteristic of three post-mining aquatic ecosystems. Methods. In total, 36 species were identified that were characteristic of three waterbodies: a salt aquatic complex (water outflow, a drainage ditch and a pond), a mined iron ore reservoir and a mined lignite reservoir. Their ecological indicator values were calculated using OMNIDIA software, and the environmental conditions prevailing in the studied ecosystems were determined. Of the 36 characteristic species, 16 lacking at least one assigned ecological indicator value were analysed further. The analysis identified three groups of selected characteristic species which showed a correlation, or lack of such, to the tested physical and chemical parameters. Results. Based on this multistage study of the autecology of characteristic diatoms, comprising an analysis of environmental conditions, literature analysis and reference ecological indicator values of other species, it is proposed that 32 ecological indicator values be established or adjusted for 16 species, and that Planothidium frequentissimum be excluded from water quality assessments.

scholarly journals Redox-Controlled Ammonium Storage and Overturn in Ediacaran Oceans

2021 ◽  
Vol 9 ◽  
Author(s):  
Christian Hallmann ◽  
Emmanuelle Grosjean ◽  
Nathan D. Shapiro ◽  
Yuichiro Kashiyama ◽  
Yoshito Chikaraishi ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Surface Waters ◽  
Primary Productivity ◽  
Environmental Conditions ◽  
Ammonium Assimilation ◽  
Early Cambrian ◽  
Anoxygenic Phototrophs ◽  
Molecular Speciation ◽  
Variable Regime ◽  
Chlorophyll Derivatives

As a key nutrient, nitrogen can limit primary productivity and carbon cycle dynamics, but also evolutionary progress. Given strong redox-dependency of its molecular speciation, environmental conditions can control nitrogen localization and bioavailability. This particularly applies to periods in Earth history with strong and frequent redox fluctuations, such as the Neoproterozoic. We here report on chlorophyll-derived porphyrins and maleimides in Ediacaran sediments from Oman. Exceptionally light δ15N values (< –10‰) in maleimides derived from anoxygenic phototrophs point towards ammonium assimilation at the chemocline, whereas the isotopic offset between kerogens and chlorophyll-derivatives indicates a variable regime of cyanobacterial and eukaryotic primary production in surface waters. Biomarker and maleimide mass balance considerations imply shallow euxinia during the terminal Ediacaran and a stronger contribution of anoxygenic phototrophs to primary productivity, possibly as a consequence of nutrient ‘lockup’ in a large anoxic ammonium reservoir. Synchronous δ13C and δ15N anomalies at the Ediacaran–Cambrian boundary may reflect one in a series of overturn events, mixing ammonium and isotopically-light DIC into oxic surface waters. By modulating access to nitrogen, environmental redox conditions may have periodically affected Ediacaran primary productivity, carbon cycle perturbations, and possibly played a role in the timing of the metazoan radiation across the terminal Ediacaran and early Cambrian.

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