| 1. |
- Dahlén, Johan, et al.
(författare)
-
Determination of nitrate and other water quality parameters in groundwater from UV/Vis spectra employing partial least squares regression
- 2000
-
Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 40:1, s. 71-77
-
Tidskriftsartikel (refereegranskat)abstract
- The use of UV/Vis spectroscopy in combination with partial least squares (PLS) regression for the simultaneous prediction of nitrate and non-purgeable organic carbon (NPOC) in groundwaters was evaluated. A model of high quality was obtained using first order derivative spectra in the range 200–300 nm. Inclusion of non-UV-absorbing constituents in the modeling procedure, i.e., chloride, sulfate, fluoride, total carbon (TC), inorganic carbon (IC), alkalinity, pH and conductivity was also evaluated. This model seemed to be useful for prediction of chloride, TC, IC, alkalinity and conductivity, while its ability to predict sulfate, fluoride and pH was poor. In conclusion, application of PLS regression, which requires neither filtration of samples nor addition of chemicals, is a promising alternative for fast interpretation of geochemical patterns of groundwater quality.
|
|
| 2. |
- Johansson, Emma, 1971-, et al.
(författare)
-
Spatial patterns of organic chlorine and chloride in Swedish forest soil
- 2003
-
Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 52:2, s. 391-397
-
Tidskriftsartikel (refereegranskat)abstract
- The concentration of organic carbon, organic chlorine and chloride was determined in Swedish forest soil in the southern part of Sweden and the spatial distribution of the variables were studied. The concentration of organically bound chlorine was positively correlated to the organic carbon content, which is in line with previous studies. However, the spatial distribution patterns strongly indicate that some other variable adds structure to the spatial distribution of organic chlorine. The distribution patterns for chloride strongly resembled the distribution of organic chlorine. The spatial distribution of chloride in soil depends on the deposition pattern which in turn depends on prevailing wind-direction, amount of precipitation and the distance from the sea. This suggests that the occurrence of organic chlorine in soil is influenced by the deposition of chloride of some variable that co-varies with chloride. Two clearly confined strata were found in the area: the concentrations of organic chlorine and chloride in the western area were significantly higher than in the eastern area. No such difference among the two areas was seen regarding the carbon content.
|
|
| 3. |
- Karlsson, Susanne, 1967-, et al.
(författare)
-
UV-light induced mineralization of organic matter bound chlorine in Lake BjΣn, Sweden - A laboratory study
- 2003
-
Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 52:2, s. 463-469
-
Tidskriftsartikel (refereegranskat)abstract
- Surface water and aqueous solutions of isolated organic matter from a humic rich lake in southern Sweden were exposed to artificial UV radiation to investigate the UV light induced influence on organic matter bound chlorine in natural systems. It was found that the photodegradation of organic matter bound chlorine was more pronounced than the photodegradation of organic carbon. After 120 h of irradiation of the isolated organic matter, only 35% of the initial organochlorine was still in the solution compared to about 70% of the dissolved organic carbon (DOC). A similar result was obtained for unfractionated surface water. Furthermore, our results indicate that the loss of organic chlorine was mainly due to a mineralization of organic chlorine into chloride ions. The total decrease of organic chlorine after 120 h was 32 ╡g Clorg l-1, of which the major part disappeared in the initial irradiation phase. A similar increase was observed in the chloride concentration (34 ╡g Cl- l-1).
|
|
| 4. |
- Rodstedth, M, et al.
(författare)
-
Chloride imbalances in soil lysimeters
- 2003
-
Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 52:2, s. 381-389
-
Tidskriftsartikel (refereegranskat)abstract
- The assumption that soil neither acts as a source or a sink of chloride is evaluated by incubating soil cores in lysimeters in a climate chamber under controlled conditions. Some of the lysimeters acted as a sink while others acted as a source of chloride. Considerable amounts of organic chlorine were lost by leaching. The loss by leaching of organic chlorine could only explain part of the discrepancy in the lysimeters where the soil acted as a sink and it could certainly not explain the cases where the soil acted as a source. The storage of organic chlorine was four times larger than the storage of chloride and comparably small changes in the organic chlorine storage will thus have a considerable influence on the chloride budget. However, the soil was too heterogeneous to determine whether a change in the storage had taken place or not. It is concluded that the observed chloride surplus and also, at least to some extent, the observed chloride deficit, most likely was caused by net-changes in the storage of organic chlorine in soil. An inverse correlation was found between the initial chloride content of the soil and the imbalance in the chloride budget. Dry deposition of chloride is generally assumed to equal the run-off minus the wet deposition. Extrapolation to the field situation suggests that the output of organic chlorine by soil leachate is at risk to cause an underestimation of the dry deposition by about 25%. (C) 2003 Elsevier Science Ltd. All rights reserved.
|
|
| 5. |
- Westblad, C., et al.
(författare)
-
A study on toxic organic emissions from batch combustion of styrene
- 2002
-
Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 49:4, s. 395-412
-
Tidskriftsartikel (refereegranskat)abstract
- Results from a laboratory-scale investigation on batch combustion of styrene are reported herein. Limited quantities of waste styrene monomer are incinerated, however this monomer is, also, the primary pyrolyzate during combustion of waste polystyrene, the second most abundant polymer produced worldwide. Thus, its combustion-generated emissions are of importance to the operation of hazardous waste incinerators and municipal waste-to-energy powerplants. This work focuses on emissions of polycyclic aromatic hydrocarbons (PAHs), particulates, as well as carbon monoxide. To investigate methods for minimizing such emissions, batch combustion of the monomer was conducted in a two-stage muffle furnace. An additional air mixing chamber was installed between the two stages. Small quantities of the liquid monomer were inserted in the primary furnace which served as a gasifier/burner. The furnace temperature was in the range of 300-1000 °C and diffusion flames were formed under most conditions. Upon mixing with additional air, combustion of unburned gaseous fuel and primary reaction products continued in the secondary furnace (afterburner), which was kept at a constant temperature of either 1000 or 800 °C. Using this technique, conditions that minimize emissions were explored and theoretical investigations on the fate of pollutants in the secondary furnace were undertaken. Results revealed that combustion of styrene, which is a highly volatile fuel, occurred with the formation of flames that were often non-anchored, unsteady and unstable. Emissions of organic pollutants, soot and CO were more intense than in the case of the polystyrene combustion, studied previously under identical conditions, due to the additional depolymerization/pyrolysis steps therein. The emissions from the secondary furnace exceeded those of the primary furnace, consistent with the fact that a very significant fraction of the fuel conversion occurred in the secondary chamber. Clear trends in the emissions of PAHs and soot, products of incomplete combustion, with the temperature of the primary furnace (gasifier) were observed. Emissions were drastically reduced with lowering the gasifier temperature. While final cumulative emissions of PAHs and soot accounted for more than one third of the mass of the fuel at high temperatures, their concentrations at the exit of the afterburner were negligible when the primary furnace was operated at 300 °C under pyrolytic conditions. In the latter case air was added to the afterburner. Numerical modeling based on a complex reaction network was used for the description of the primary furnace as well as of the afterburner. Kinetic analysis showed acetylene and benzene to be key species in the growth of PAHs. Formation of PAHs in the afterburner, found experimentally, was reproduced by the model using a plug-flow assumption. © 2002 Elsevier Science Ltd. All rights reserved.
|
|
| 6. |
- Öberg, Gunilla, 1961-, et al.
(författare)
-
Chloroperoxidase-mediated chlorination of aromatic groups in fulvic acid
- 2000
-
Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 41:5, s. 779-785
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study is to investigate whether exo-enzymatically mediated chlorination of fulvic acid (FA) results in the formation of chlorinated groups within the macromolecules which correspond to those which were previously detected in soil and surface water samples. The chlorination was carried out by exposing FA to a commercial chloroperoxidase (CPO) in the presence of chloride and hydrogen-peroxide. The exposed FA was then chemically degraded using an oxidative technique and finally analysed for four different aromatic groups and their chlorinated analogues. The particular aromatic groups included were the methyl esters of 4-ethoxybenzoic acid, 3-methoxy-4-ethoxybenzoic acid, 3,4-diethoxybenzoic acid, and 3,5- dimethoxy-4-ethoxybenzoic acid, along with their mono-and dichlorinated analogues. Prior to the chemical degradation procedure, the FA was analysed for AOX (adsorbable organic halogens) and chlorinated acetic acids. The original FA contained 1.4 mg Cl(org) g-1 and detectable amounts of two chlorinated aromatic groups. After exposure to the enzyme, the concentration of AOX increased to 44.3 mg Cl(org) g-1 and detectable amounts of four chlorinated aromatic groups as well as di- and trichloroacetic acid were found. (C) 2000 Elsevier Science Ltd.
|
|
| 7. |
- Araújo, Mário J, et al.
(författare)
-
Proteomics reveals multiple effects of titanium dioxide and silver nanoparticles in the metabolism of turbot, Scophthalmus maximus
- 2022
-
Ingår i: Chemosphere. - : Pergamon-Elsevier Science Ltd. - 0045-6535 .- 1879-1298. ; 308
-
Tidskriftsartikel (refereegranskat)abstract
- Titanium dioxide (TiO2) and silver (Ag) NPs are among the most used engineered inorganic nanoparticles (NPs); however, their potential effects to marine demersal fish species, are not fully understood. Therefore, this study aimed to assess the proteomic alterations induced by sub-lethal concentrations citrate-coated 25 nm ("P25") TiO2 or polyvinylpyrrolidone (PVP) coated 15 nm Ag NPs to turbot, Scophthalmus maximus. Juvenile fish were exposed to the NPs through daily feeding for 14 days. The tested concentrations were 0, 0.75 or 1.5 mg of each NPs per kg of fish per day. The determination of NPs, Titanium and Ag levels (sp-ICP-MS/ICP-MS) and histological alterations (Transmission Electron Microscopy) supported proteomic analysis performed in the liver and kidney. Proteomic sample preparation procedure (SP3) was followed by LC-MS/MS. Label-free MS quantification methods were employed to assess differences in protein expression. Functional analysis was performed using STRING web-tool. KEGG Gene Ontology suggested terms were discussed and potential biomarkers of exposure were proposed. Overall, data shows that liver accumulated more elements than kidney, presented more histological alterations (lipid droplets counts and size) and proteomic alterations. The Differentially Expressed Proteins (DEPs) were higher in Ag NPs trial. The functional analysis revealed that both NPs caused enrichment of proteins related to generic processes (metabolic pathways). Ag NPs also affected protein synthesis and nucleic acid transcription, among other processes. Proteins related to thyroid hormone transport (Serpina7) and calcium ion binding (FAT2) were suggested as biomarkers of TiO2 NPs in liver. For Ag NPs, in kidney (and at a lower degree in liver) proteins related with metabolic activity, metabolism of exogenous substances and oxidative stress (e.g.: NADH dehydrogenase and Cytochrome P450) were suggested as potential biomarkers. Data suggests adverse effects in turbot after medium/long-term exposures and the need for additional studies to validate specific biological applications of these NPs.
|
|
| 8. |
|
|
| 9. |
- Caliz, Joan, et al.
(författare)
-
The microbiota of an unpolluted calcareous soil faces up chlorophenols: Evidences of resistant strains with potential for bioremediation
- 2011
-
Ingår i: Chemosphere. - : Elsevier Science B.V., Amsterdam.. - 0045-6535 .- 1879-1298. ; 83:2, s. 104-116
-
Tidskriftsartikel (refereegranskat)abstract
- To highlight the effects of a variety of chlorophenols (CP) in relation to the response of an indigenous bacterial community, an agricultural Mediterranean calcareous soil has been studied in microcosms incubated under controlled laboratory conditions. Soil samples were artificially polluted with 2-monochlorophenol (MCP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP), at concentrations ranging from 0.1 up to 5000 mg kg(-1). Both activity and composition of the microbial community were assessed during several weeks, respectively, by respirometric methods and PCR-DGGE analysis of extracted DNA and RNA. Significant decreases in soil respirometric values and changes in the bacterial community composition were observed at concentrations above 1000 mg kg(-1) MCP and TCP, and above 100 mg kg(-1) PCP. However, the persistence of several active bacterial populations in soil microcosms contaminated with high concentration of CP, as indicated by DGGE fingerprints, suggested the capacity of these native bacteria to survive in the presence of the pollutants, even without a previous adaptation or contact with them. The isolation of potential CP degraders was attempted by culture plating from microcosms incubated with high CP concentrations. Twenty-three different isolates were screened for their resistance to TCP and PCP. The most resistant isolates were identified as Kocuria palustris, Lysobacter gummosus, Bacillus sp. and Pseudomonas putida, according to 16S rRNA gene homology. In addition, these four isolates also showed the capacity to reduce the concentration of TCP and PCP from 15% to 30% after 5 d of incubation in laboratory assays (initial pollutant concentration of 50 mg L(-1)). Isolate ITP29, which could be a novel species of Bacillus, has been revealed as the first known member in this bacterial group with potential for CP bioremediation applications, usually wide-spread in the soil natural communities, which has not been reported to date as a CP degrader.
|
|
| 10. |
- Campos-Pereira, Hugo, et al.
(författare)
-
Effect of pH, surface charge and soil properties on the solid-solution partitioning of perfluoroalkyl substances (PFASs) in a wide range of temperate soils
- 2023
-
Ingår i: Chemosphere. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0045-6535 .- 1879-1298. ; 321
-
Tidskriftsartikel (refereegranskat)abstract
- The pH-dependent soil-water partitioning of six perfluoroalkyl substances (PFASs) of environmental concern (PFOA, PFDA, PFUnDA, PFHxS, PFOS and FOSA), was investigated for 11 temperate mineral soils and related to soil properties such as organic carbon content (0.2-3%), concentrations of Fe and Al (hydr)oxides, and texture. PFAS sorption was positively related to the perfluorocarbon chain length of the molecule, and inversely related to solution pH for all substances. The negative slope between log Kd and pH became steeper with increasing perfluorocarbon chain length of the PFAS (r2 = 0.75, p <= 0.05). Organic carbon (OC) alone was a poor predictor of the partitioning for all PFASs, except for FOSA (r2 = 0.71), and the OC-normalized PFAS partitioning, as derived from organic soil materials, underestimated PFAS sorption to the soils. Multiple linear regression suggested sorption contributions (p <= 0.05) from OC for perfluorooctane sulfonate (PFOS) and FOSA, and Fe/Al (hydr) oxides for PFOS, FOSA, and perfluorodecanoate (PFDA). FOSA was the only substance under study for which there was a statistically significant correlation between its binding and soil texture (silt + clay). To predict PFAS sorption, the surface net charge of the soil organic matter fraction of all soils was calculated using the Stockholm Humic Model. When calibrated against charge-dependent PFAS sorption to a peat (Oe) material, the derived model significantly underestimated the measured Kd values for 10 out of 11 soils. To conclude, additional
|
|
