The WHAM-FTOX model quantifies the combined toxic effects of protons and metal cations towards aquatic organisms through the toxicity function (FTOX), a linear combination of the products of organism-bound cation and a toxic potency coefficient for each cation. We describe the application of the model to predict an observable ecological field variable, species richness of pelagic lake crustacean zooplankton, studied with respect to either acidification or the impacts of metals from smelters. The fitted results give toxic potencies increasing in the order H(+) < Al < Cu < Zn < Ni. In general, observed species richness is lower than predicted, but in some instances agreement is close, and is rarely higher than predictions. The model predicts recovery in agreement with observations for three regions, namely Sudbury (Canada), Bohemian Forest (Czech Republic) and a subset of lakes across Norway, but fails to predict observed recovery from acidification in Adirondack lakes (USA).

• MeSH
• chemické látky znečišťující vodu toxicita   MeSH
• chemické modely * MeSH
• jezera chemie   MeSH
• korýši klasifikace   účinky léků   růst a vývoj   MeSH
• kovy toxicita   MeSH
• monitorování životního prostředí metody   MeSH
• protony MeSH
• zooplankton klasifikace   účinky léků   růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Česká republika MeSH
• Kanada MeSH
• Norsko MeSH

The diffusive gradient in the film technique (DGT) is a new approach to the in-situ determinations of labile metal species in aquatic systems. The DGT device accumulates labile species from solution and therefore contamination problems associated with conventional collection and filtration procedures are eliminated. The technique employs a hydrogel layer to control the diffusive transport of metals to a cation-exchange resin, which is selective for free or weakly complexed metal ion species. This study deals with the use of a new resin based on the Spheron-Oxin® ion exchanger in the DGT technique. The resin with a selectivity for trace metal species higher than Chelex 100 could provide more information on metal speciation in aquatic systems. Its performance was tested for Cd, Cu, Ni and Pb under laboratory conditions. The new resin provides reliable results in the pH range 6-8, independently of ionic strength (25 mmol l-1- 0.6 mol l-1) and also in the presence of Mg(NO3)2 (10 µmol l-1 - 0.05 mol l-1). The effect of iminodiacetic acid, as a model competitive ligand on the metal uptake measured by DGT probe was also assessed.

• MeSH
• financování organizované MeSH
• gely MeSH
• iontoměniče MeSH
• kovy analýza   MeSH
• látky znečišťující životní prostředí analýza   MeSH

Metal smelting is often responsible for local contamination of environmental compartments. Dust materials escaping from the smelting facilities not only settle in the soil, but can also have direct effects on populations living close to these operations (by ingestion or inhalation). In this particular study, we investigate dusts from Cu-Co metal smelters in the Zambian Copperbelt, using a combination of mineralogical techniques (XRD, SEM/EDS, and TEM/EDS), in order to understand the solid speciation of the contaminants, as well as their bioaccessibility using in vitro tests in simulated gastric and lung fluids to assess the exposure risk for humans. The leaching of metals was mainly dependent on the contaminant mineralogy. Based on our results, a potential risk can be recognized, particularly from ingestion of the dust, with bioaccessible fractions ranging from 21 to 89% of the total contaminant concentrations. In contrast, relatively low bioaccessible fractions were observed for simulated lung fluid extracts, with values ranging from 0.01% (Pb) up to 16.5% (Co) of total contaminant concentrations. Daily intakes via oral exposure, calculated for an adult (70 kg, ingestion rate 50 mg dust per day), slightly exceeded the tolerable daily intake limits for Co (1.66× for fly ash and 1.19× for slag dust) and occasionally also for Pb (1.49×, fly ash) and As (1.64×, electrostatic precipitator dust). Cobalt has been suggested as the most important pollutant, and the direct pathways of the population's exposures to dust particles in the industrial parts of the Zambian Copperbelt should be further studied in interdisciplinary investigations.

• MeSH
• arsen analýza   MeSH
• biologické modely MeSH
• dospělí MeSH
• hodnocení rizik MeSH
• hutnictví * MeSH
• látky znečišťující vzduch analýza   MeSH
• lidé MeSH
• monitorování životního prostředí * MeSH
• prach analýza   MeSH
• průmysl MeSH
• techniky in vitro MeSH
• těžké kovy analýza   MeSH
• velikost částic MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Zambie MeSH

The impact of a natural wetland ("dambo" in Zambia) on neutral mine drainage at Luanshya in the Zambian Copperbelt has been investigated during an intermediate discharge period (July) using a multi-method characterization of solid phase samples, sequential extraction analysis, X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy combined with water analyses, isotopic analyses, and geochemical modeling. In the wetland, the principal identified solid phases in sediments were carbonates, gypsum, and ferric oxyhydroxides. A significant portion of the ochres was present as insoluble hematite. Mine drainage pH values decrease, and log [Formula: see text] values increase after inflow of water into the wetland; dissolved and suspended concentrations of Fe, Mn, Cu, and Co also decrease. Based on speciation calculations, there is no precipitation of secondary Cu and Co minerals in the period of sampling, but it can occur later in dry period when the flow rate is reduced. Concentrations of sulfate decrease, and values of δ34S(SO4) in the wetland increase in parallel, suggesting sulfate reduction is occurring. In more advanced dry period, the discharge in mine drainage stream is probably much lower and water can reach supersaturation with respect to minerals such as gypsum, which has been found in sediments. Wetlands have a positive impact on mine drainage water quality due to the removal of metals by adsorption, co-precipitation, and filtration of colloids. However, there can also be a rebound of contamination by seepage inflow downstream from the wetland. Ongoing climate change with extreme hydrologic events may enhance differences between dry and rainy seasons with resulting faster mobilization of contaminants.

• MeSH
• adsorpce MeSH
• chemická precipitace MeSH
• chemické látky znečišťující vodu analýza   MeSH
• difrakce rentgenového záření MeSH
• filtrace MeSH
• hornictví * MeSH
• klimatické změny * MeSH
• koloidy MeSH
• minerály chemie   MeSH
• mokřady * MeSH
• monitorování životního prostředí * metody   MeSH
• odpadní voda chemie   MeSH
• počasí MeSH
• roční období MeSH
• síran vápenatý chemie   MeSH
• sírany analýza   MeSH
• těžké kovy analýza   MeSH
• uhličitany chemie   MeSH
• železité sloučeniny MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Zambie MeSH

We assessed the relationship between the diffusive gradient in thin film (DGT) technique using the new ion-exchange resin Ambersep GT74 and the uptake of mercury (Hg) by a model plant cultivated on metal-contaminated agricultural soils under greenhouse conditions. Based on the total Hg content, 0.37 to 1.17% of the Hg passed to the soil porewater from the solid phase, and 2.18 to 9.18% of the Hg is DGT-available. These results were confirmed by calculating the R value (the ratio of the concentrations of bioavailable Hg measured by DGT and soil solution), which illustrated the strong bonding of Hg to the solid phase of soil and its extremely low mobility. Only inorganic Hg2+ species were found in the metal-contaminated agricultural soils, as determined by a high-performance liquid chromatography-cold vapor atomic fluorescence spectrometry speciation analysis. The Hg was distributed in Miscanthus × giganteus organs in the following order for all sampling sites: roots (55-82%) > leaves (8-27%) > stems (7-16%) > rhizomes (4-7%). Environ Toxicol Chem 2019;38:321-328. © 2018 SETAC.

• MeSH
• biologická dostupnost MeSH
• biologické modely MeSH
• biologický transport MeSH
• iontoměniče chemie   MeSH
• látky znečišťující půdu analýza   metabolismus   MeSH
• lipnicovité metabolismus   MeSH
• monitorování životního prostředí metody   MeSH
• půda chemie   MeSH
• rtuť analýza   metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Arsenic is one of the inorganic pollutants typically found in natural waters, and its toxic effects on the human body are currently of great concern. For this reason, the search for detoxifying agents that can be used in a so-called "chelation therapy" is of primary importance. However, to the aim of finding the thermodynamic behavior of efficient chelating agents, extensive speciation studies, capable of reproducing physiological conditions in terms of pH, temperature, and ionic strength, are in order. Here, we report on the acid-base properties of meso-2,3-dimercaptosuccinic acid (DMSA) at different temperatures (i.e., T = 288.15, 298.15, 310.15, and 318.15 K). In particular, its capability to interact with As(III) has been investigated by experimentally evaluating some crucial thermodynamic parameters (ΔH and TΔS), stability constants, and its speciation model. Additionally, in order to gather information on the microscopic coordination modalities of As(III) with the functional groups of DMSA and, at the same time, to better interpret the experimental results, a series of state-of-the-art ab initio molecular dynamics simulations have been performed. For the sake of completeness, the sequestering capabilities of DMSA-a simple dithiol ligand-toward As(III) are directly compared with those recently emerged from similar analyses reported on monothiol ligands.

• MeSH
• arsen chemie   izolace a purifikace   MeSH
• chelátory chemie   MeSH
• koncentrace vodíkových iontů MeSH
• kyselina dimerkaptojantarová chemie   MeSH
• lidé MeSH
• ligandy MeSH
• molekulární struktura MeSH
• simulace molekulární dynamiky MeSH
• tělesné tekutiny chemie   MeSH
• termodynamika MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• měď toxicita   škodlivé účinky   MeSH
• pracovní expozice MeSH
• vystavení vlivu životního prostředí MeSH

• Konspekt
• Lékařské vědy. Lékařství
• NLK Obory
• toxikologie
• environmentální vědy
• environmentální vědy
• NLK Publikační typ
• publikace WHO

• MeSH
• nikl toxicita   MeSH
• pracovní expozice MeSH
• znečištění životního prostředí MeSH

• Konspekt
• Veřejné zdraví a hygiena
• NLK Obory
• environmentální vědy