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- Bertling, Sofia, 1970-
(författare)
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Corrosion-included metal runoff from external constructions and its environmental interaction : a combined field and laboratory investigation of Zn, Cu, Cr and Ni for risk assessment
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The 1990s has seen an increased awareness of possible environmental effects of corrosion-induced metal release from outdoor constructions. Considerable efforts have been initiated to perform critical assessments of possible risks of selected metals. Gaps of knowledge have been identified and research investigations started. This doctoral thesis is the result of an interdisciplinary research effort in which scientific insight into corrosion, soil chemistry and ecotoxicology has been integrated. The work comprises atmospheric exposure of pure metals and commercial materials for outdoor use. The focus is on release of four metals, copper, zinc, chromium and nickel. Their chemical speciation and bioavailable fraction in metal runoff were determined, both at the release moment and after environmental interaction with, e.g., soil and limestone. Total metal concentrations in runoff are influenced both by material properties (e.g., corrosion product solubility, and specific surface area) and by exposure parameters (e.g., rain volume, intensity, contact time and pollutants). Long-term runoff rates of copper, zinc, chromium and nickel were based on exposures (4-8 years) at standardized conditions (45o inclination facing south) in Stockholm, Sweden. Runoff rates for pure copper range from 1.2 to 1.5 g m-2 yr-1, depending on year. At the copper release moment the potential environmental effect was evaluated using 72 hours growth inhibition test with the green algae Raphidocelis subcapitata. This resulted in a mean value of 15 μg L-1 causing a 50% growth reduction (EC50). Long-term runoff rates for pure zinc range from 1.9 to 2.5 g m-2 yr-1. A considerable variation in average annual runoff rates (0.07-2.5 mg zinc m2yr-1) was observed between different investigated commercial zinc-based materials. An average 72 hour (EC50) value of 69 μg L-1 towards Raphidocelis subcapitata was found for runoff water from zinc-based materials. Long-term runoff rates from stainless steel of grade 304 and 316 range from 0.23 to 0.30 chromium and 0.28 to 0.52 nickel mg m-2 yr-1, with corresponding concentrations in the runoff at the release moment far below reported ecotoxic concentrations for chromium and nickel. Two predictive runoff rate models were successfully developed for transforming copper runoff rate data from Stockholm to other exposure sites. One model is based on rain pH, yearly precipitation and building geometry, and the other on average annual SO2 concentration, yearly precipitation and building geometry. In addition to total metal concentration, adequate effect assessments also require information on chemical speciation of the released metal and its bioavailability. Metal chemical speciation in runoff was determined experimentally through an ion selective electrode (for copper), and also modelled with the Windermere Humic Aquatic model (WHAM (V)). Bioavailability assessments were generated through bioassay tests. At the moment of metal release, all methods show that the majority (60-99%) of the metal in runoff exists in its most bioavailable form, the hydrated metal ion. During subsequent environmental entry the metal undergoes major reductions in concentration and bioavailability. This was evidenced by model column studies of the capacity of soil to retain and immobilize the metal in runoff water, and by model and field column studies of the capacity of limestone to retain copper. The retention by soil of all metals investigated is very high (96-99.8%) until each materials retention capacity is reached. Limestone also exhibits a substantial capacity (5- 47%) to retain copper. The capacity is significantly increased by increased amount and decreased fraction of limestone particles. Any outer or inner surface with significant retention ability and with low possibility of subsequent mobilization is an excellent candidate for neutralizing metal release and its potential ecotoxic effects. This was demonstrated through computer modelling (WHAM(V)) and biosensor tests (Biomet™), which showed the most bioavailable and ecotoxic metal species to be reduced during passage through soil and limestone. Predictions based on the computer model HYDRUS-1D suggest a time-period of between 4 and 8000 years, depending on runoff water and soil characteristics, before saturation in soil retention capacity of copper and zinc is reached. A significant fraction of the retained metal is extractable towards the strong complexing agent EDTA, indicating possible future mobilisation. It is also available for plant uptake, as shown by DGT- (Diffuse Gradients in Thin films-) analysis of copper and zinc in soil. The data generated, presented and discussed are all believed to be important for risk assessment work related to corrosion-induced metal release from outdoor constructions. As evidenced from this doctoral thesis, such work requires a complete set of data on annual runoff rates, concentrations, chemical speciation and bioavailability and its changes during environmental entry, together with knowledge on, e.g., type of material, service life of coating, building geometry, and dewatering system.
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- Bertling, Sofia, et al.
(författare)
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Environmental effects of zinc runoff from roofing materials : a new multidisciplinary approach
- 2002
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Ingår i: Outdoor Atmospheric Corrosion. - 0803128967 ; , s. 200-215
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Konferensbidrag (refereegranskat)abstract
- The objective of this work is to study changes in concentration and bioavailability of zinc-containing runoff water, released from roofing materials, upon passage through soil. The experimental approach is based on simulating the interaction between zinc in artificial runoff water and soil in a column system. The total zinc concentration of runoff was substantially reduced when passing through the soil and suggests marked zinc retention, During a constant flow and supply of zinc into the soil, equivalent to three and a half years of precipitation in Stockholm, a zinc retention capacity of approximately 99% was recorded, Not only the total concentration, but also the bio-available portion of the total zinc concentration was reduced after passage through soil, Most of the retained zinc was located in top 3 cm of the soil core and suggests the total capacity for zinc retention of the investigated soil to be about 140 years per kilogram soil in an isolated system in real systems, changes of temperature, pH, microbial activity, weathering of minerals and deposition of new organic material must be considered. The results form part of the effect assessment, preceding future risk assessment of the environmental effects of dispersed zinc.
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- Bertling, Sofia, et al.
(författare)
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Long-term corrosion-induced copper runoff from natural and artificial patina and its environmental impact
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268 .- 1552-8618. ; 25:3, s. 891-898
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Tidskriftsartikel (refereegranskat)abstract
- The overall objective of this paper is to present an extensive set of data for corrosion-induced copper dispersion and its environmental interaction with solid surfaces in the near vicinity of buildings. Copper dispersion is discussed in terms of total copper flows, copper speciation and bioavailability at the immediate release situation, and its changes during transport from source to recipient. Presented results are based on extensive field exposures (eight years) at an urban site, laboratory investigations of the runoff process, published field data, generated predictive site-specific runoff rate models, and reactivity investigations toward various natural and manmade surfaces, such as those in soil, limestone, and concrete. Emphasis is placed on the interaction of copper-containing runoff water with different soil systems through long-term laboratory column investigations. The fate of copper is discussed in terms of copper retention, copper chemical speciation, breakthrough capacities, and future mobilization based on changes in copper concentrations in the percolate water, computer modeling using the Windermere Humic Aqueous Model, and sequential extractions. The results illustrate that, for scenarios where copper comes in extensive contact with solid surfaces, such as soil and limestone, a large fraction of released copper is retained already in the immediate vicinity of the building. In all, both the total copper concentration in runoff water and its bioavailable part undergo a significant and rapid reduction.
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- Bertling, Sofia, et al.
(författare)
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Model studies of corrosion induced copper runoff fate in soil
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268 .- 1552-8618. ; 25:3, s. 683-691
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Tidskriftsartikel (refereegranskat)abstract
- Laboratory experiments have been performed with 3-cm soil columns simulating the fate of corrosion-induced copper runoff in contact with soil. The investigation simulates approximately 30 years (assuming an infiltration surplus of 25 cm/year) of continuous percolation of copper containing runoff water of a concentration realistic at the immediate release situation (4.8 mg/L) into four soils representative of urban conditions. Two of the three investigated topsoils reached their breakthrough of copper within the simulated time, while the third topsoil did not show a breakthrough. The subsoil reached a breakthrough after approximately 10 years of simulated exposure. To simulate more realistic outdoor scenarios, the laboratory-obtained breakthrough curves were modeled with Hydrus-1D (R) using a Langmuir-Freundlich model to describe copper sorption, the parameters of which were estimated from soil properties (pH, organic carbon content). The model predicts longer breakthrough times with increasing pH and organic content of the soil and with decreasing concentrations of copper and dissolved organic carbon in the runoff water. The time span for copper in runoff water (at concentrations of 0.01-10 mg/L) to reach a soil depth of 50 cm varied between 170 and more than 8,000 years for the predicted field scenarios.
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| 7. |
- Bertling, Sofia, et al.
(författare)
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Occurrence and fate of corrosion-induced zinc in runoff water from external structures
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 367:2-3, s. 908-923
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Tidskriftsartikel (refereegranskat)abstract
- This paper comprises data from an extensive cross-disciplinary research project aiming to elucidate the environmental fate of corrosion-induced zinc release from external structures. It includes an exposure assessment that provide long-term runoff rates, concentrations and chemical speciation of zinc, from 14 zinc-based materials exposed during 5 years in Stockholm, Sweden, and an effect assessment including bioavailability and ecotoxicity measurements, both at the immediate release situation and after soil interaction.Runoff rates of total zinc ranged from 0.07 to 2.5g Znm(-2) yr(-1) with zinc primarily released as the free ion for all materials investigated. The average effect concentration, causing a 50% growth reduction after 72h to the green algae Raphidocelis subcapitata, was at the immediate release situation 69 mu g ZnL-1. Upon interaction of runoff water with soil, which simulated 18 to 34years of exposure, the total zinc concentration was significantly reduced, from milligram per litre to microgram per litre levels. Simultaneously, the most bioavailable fraction of zinc in runoff, the hydrated zinc(II)-ion, decreased from more than 95% to about 30%. The major fraction, 98-99%, of the introduced total zinc concentration in the runoff water was retained within the soil. As long as the soil retention capacity was not reached, this resulted in zinc concentrations in the percolate water transported through the soil layer, close to background values and below growth inhibition concentrations for the green algae investigated. Zinc retained in soil was to a large extent (85-99.9%) extractable with EDTA, and available for plant uptake after 5 to 7months of ageing.
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- Odnevall Wallinder, Inger, et al.
(författare)
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Corrosion-induced release and environmental interaction of chromium, nickel and iron from stainless steel
- 2006
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Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 170:1-4, s. 17-35
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Tidskriftsartikel (refereegranskat)abstract
- A cross-disciplinary research project has been implemented because of increased awareness of the potential environmental effects caused by dispersion of metals from external applications into the environment. The work comprises a 4-year (1998-2002) field exposure of grades 304 and 316 stainless steels, and a laboratory percolation study simulating 20-25 years of chromium and nickel containing runoff water interactions with soil. Total metal annual release rates varied between 0.2 and 0.7 mg m(-2) yr(-1) for Cr, between 0.1 and 0.8 mg m(-2) yr(-1) for Ni and between 10 and 200 mg m(-2) yr(-1) for Fe. Most Cr and Ni is present in an ionic form as a result of the limited presence of organic matter at the immediate release situation. Metal ion concentrations in the runoff water are far below reported ecotoxic concentrations. Studies of the environmental interaction between runoff water from stainless steel and soil show the majority of released Cr and Ni to be retained and their concentrations in percolation water to be very low (0.5-1 mu g L-1 and 1-5.5 mu g L-1 for Cr and Ni, respectively). Speciation calculations showed Cr to be primarily complexed to dissolved organic carbon while Ni also was present in an ionic form in the solution phase. Soil extractions showed Cr and Ni to be very strongly retained within the soil.
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