Mercury Release from Soils Amended with Flue Gas Desulfurization Solids (original) (raw)
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Journal of environmental quality, 2018
Flue gas desulfurization gypsum (FGDG) from coal-fired power plants is readily available for agricultural use in many US regions. Broiler litter (BL) provides plant available N, P, and K but can be a source of unwanted As, Cu, and Zn. As a source of Ca and S, FGDG can reduce losses of P and other elements in runoff from BL-amended areas. Rainfall simulation plots (2.0 m) were established on a Piedmont Cecil soil growing 'Coastal' bermudagrass ( L.) for hay. Accumulation and transport of As, Cu, Cd, Cr, Hg, Pb, and Zn were evaluated after annual BL applications (13.5 Mg ha) with four FGDG rates (0, 2.2, 4.5, 9.0 Mg ha) and two FGDG treatments (0 and 9 Mg ha) without BL. Runoff As concentrations were sixfold greater with BL than without ( ≤ 0.01) and were similar to BL with FGDG at 2.2, 4.5 or 9.0 Mg ha ( ≤ 0.10). Runoff concentrations of target elements did not increase where FGDG was applied alone. After three annual applications of FGDG and BL, soil concentrations of As, Cr...
Journal of the Air & Waste Management Association, 2008
This paper describes a project that assessed the potential for mercury (Hg) release to air and water from soil amended with combustion products to simulate beneficial use. Combustion products (ash) derived from wood, sewage sludge, subbituminous coal, and a subbituminous coal-petroleum coke mixture were added to soil as agricultural supplements, soil stabilizers, and to develop lowpermeability surfaces. Hg release was measured from the latter when intact and after it was broken up and mixed into the soil. Air-substrate Hg exchange was measured for all materials six times over 24 hr, providing data that reflected winter, spring, summer, and fall meteorological conditions. Dry deposition of atmospheric Hg and emission of Hg to the atmosphere were both found to be important fluxes. Measured differences in seasonal and diel (24 hr) fluxes demonstrated that to establish an annual estimate of air-substrate flux from these materials data on both of these time steps should be collected. Air-substrate exchange was highly correlated with soil and air temperature, as well as incident light. Hg releases to the atmosphere from coal and wood combustion product-amended soils to simulate an agricultural application were similar to that measured for the unamended soil, whereas releases to the air for the sludge-amended materials were higher. Hg released to soil solutions during the Synthetic Precipitation Leaching Procedure for ashamended materials was higher than that released from soil alone. On the basis of estimates of annual releases of Hg to the air from the materials used, emissions from coal and wood ash-amended soil to simulate an agricultural application could simply be re-emission of Hg deposited by wet processes from the atmosphere; however, releases from sludge-amended materials and those generated to simulate soil stabilization and disturbed low-permeability pads include Hg indigenous to the material. IMPLICATIONS Ash generated from the combustion of coal, wood, and sewage sludge may be placed in landfills or put to some beneficial use. This project investigated the potential for Hg release to air and water from combustion products amended to soils as an agricultural supplement, soil stabilizer, and to generate a low-permeability surface. Data indicated that to develop accurate estimates of Hg release diel and seasonal measurements of air-surface exchange are necessary. Additionally, Hg releases will depend upon intrinsic characteristics of the material as well as the amount applied.
Environmental Earth Sciences, 2016
The mobility of mercury and its transformation as affected by different sulfur-rich amendments were investigated in a model laboratory incubation experiment. Two soils, Chernozem and Luvisol, differing in their physicochemical characteristics, were selected for the experiment. The soils were artificially contaminated with Hg by adding HgCl 2 solution to a final concentration of 12 mg kg-1 of Hg in the soils. Subsequently, organic and inorganic amendments: (1) (NH 4) 2 SO 4 , (2) L-cysteine, and (3) digestate, a biowaste from a biogas station, were applied and the soils were incubated for 21 days in the dark. Soil samples were collected after 1, 7, 14 and 21 days of incubation. At the individual sampling times 30 g of each soil was collected for determinations of pH, the mobile Hg pool, carbon derived from microbial biomass, and dehydrogenase activity. The results confirmed the important role of digestate application leading to (1) improved nutrient status and microbiological activity in the contaminated soils and (2) an increased proportion of methylmercury in the soils as well as a decrease in mercury volatilization. These findings suggested that digestate could be applied to Hg contaminated soil for effective stabilization of this element in the soil. However, long-term experiments are necessary for an evaluation of further potential Hg transformations due to the decomposition of digestate-bearing organic matter.
Thermal-Treated Soil for Mercury Removal: Soil and Phytotoxicity Tests
Journal of Environmental Quality, 2000
Mercury (Hg) contamination of soils and sediments is one of many environmental problems at the Oak Ridge Reservation, Oak Ridge, TN. Mercury-contaminated soil from the Lower East Fork Poplar Creek (LEFPC) at the Oak Reservation was treated thermally reduce Hg concentration to a below target level (20 mg kg-~) as a pilot scale thermal treatment demonstration. As a part of performance evaluation, the soil characteristics and plant growth response of the untreated and treated soil were examined. The soil treated at 350°C retained most of its original soil properties, but the soil treated at 600°C exhibited considerable changes in mineralogical composition and physicochemical characteristics. Growth and physiological response of the three plant species radish (Raphanus sativus L.), fescue (Festuca arundinacea Schreb.), and oat (Avena sativa L.) indicated adverse effects of the thermal treatment. The addition of N fertilizer had beneficial effects in the 350°C treated soil, but had little beneficial effects in the 600°C treated soil. Some changes of soil characteristics induced by thermal treatment cannot be avoided. Soil characteristics and phytotoxicity test results strongly suggest that changes occurring following the 350°C treatment do not limit the use of the treated soil to refill the excavated site for full-scale remediation. The only problem with the 350°C treatment is that small amounts of Hg compounds (<15 mg kg-~) remain in the soil and a processing cost of $45/Mg.
The Scientific World Journal, 2014
Both soil organic matter and sulfur (S) can reduce or even suppress mercury (Hg) mobility and bioavailability in soil. A batch incubation experiment was conducted with a Chernozem and a Luvisol artificially contaminated by 440 mg⋅kg −1 Hg showing wide differences in their physicochemical properties and available nutrients. The individual treatments were (i) digestate from the anaerobic fermentation of biowaste; (ii) fly ash from wood chip combustion; and (iii) ammonium sulfate, and every treatment was added with the same amount of S. The mobile Hg portion in Chernozem was highly reduced by adding digestate, even after 1 day of incubation, compared to control. Meanwhile, the outcome of these treatments was a decrease of mobile Hg forms as a function of incubation time whereas the contents of magnesium (Mg), potassium (K), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), and phosphorus (P) were stimulated by the addition of digestate in both soils. The available calcium (Ca) contents were not affected by the digestate addition. The experiment proved digestate application as the efficient measure for fast reduction of mobile Hg at extremely contaminated soils. Moreover, the decrease of the mobile mercury portion was followed by improvement of the nutrient status of the soils.
2002
This is a study of mercury (Hg) and methylmercury (MeHg) cycling in the soils of a paired watershed system at Acadia National Park, Maine. Two watersheds were compared, Cadillac Brook watershed, burned in 1947, currently bas thin soils and primarily deciduous vegetation, and Hadlock Brook watershed, unburned, currently having thicker soil and coniferous vegetation The fue likely had a significant impact on Cadillac watershed, by altering the vegetation, raising the soil pH, and depleting the carbon pool. Soil pH was significantly higher in all horizons of Cadillac soils than in Hadlock soils. This difference was especially significant in the 0 horizon, where on average, Cadillac soils had a pH approximately 0.40 units higher than Hadlock soils. Total Hg concentrations were higher in the 0 horizon of Hadlock soils than in Cadillac soils, most likely as a result of the fire. Cadillac and Hadlock soils contained an estimated total Hg content of 1.70 kg and 6.64 kg, respectively. Soil MeHg concentrations were higher in Cadillac than in Hadlock, also most likely as a result of the fire. Cadillac and Hadlock soils contained an estimated MeHg content of 0.0038 kg and 0.0056 kg, respectively.
Fuel, 2010
Temperature programmed decomposition was used to identify mercury (Hg) species in gypsum samples produced from flue gas desulfurization in two Spanish power stations (A and B). As stricter emission control/reduction policies, particularly those focusing on Hg, are being implemented, wet flue gas desulfurization (FGD) technologies used for the removal of SO 2 can result in the co-removal of highly-soluble oxidized Hg. The amount of Hg retained in FGD products may increase in the future if these units are optimized for co-capture. For this reason, it is important to identify the mercury species in FGD products not only to determine the potential risk when the wastes are finally disposed of, but also to understand the behaviour of mercury during combustion and therefore to improve the technologies for mercury removal. Different mercury species were identified in the gypsum samples. In power station A, Hg-S were the most probable Hg species, whereas in power station B the main compound was Hg halogenated compounds.
Mercury species in formerly contaminated soils and released soil gases
Science of The Total Environment, 2017
Total mercury (T-Hg), elemental mercury (Hg 0), methylmercury (MeHg +), phenylmercury (PhHg +), and gaseous elemental mercury (GEM) species were determined in soils formerly contaminated by different processes from two sites in the Czech Republic. Analytical methods involved atomic absorption spectrometry (AAS) using a single-purpose Advanced Mercury Analyser AMA-254 and radiochemical neutron activation analysis (RNAA) for T-Hg determination, a thermal desorption method was used for Hg 0 determination, gas chromatography coupled with atomic fluorescence spectrometry (GC-AFS) was employed for assay of MeHg + and PhHg + , while GEM measurement was carried out using a portable Zeeman-AAS device Lumex RA-915 +. The first sampling site was in the surroundings of a former PhHgCl-based fungicide processing plant next to Příbram (central Bohemia). Although the use of Hg-based fungicides as seed mordant have been banned, and their production stopped at the end of 1980′s, highly elevated Hg contents in soil are still observed in the vicinity of the former plant, reaching T-Hg values N13 mg kg −1. The second sampling site was an abandoned mining area named Jedová hora Hill near Hořovice (central Bohemia), where cinnabar (HgS) was occasionally mined as by-product of Fe ores hematite and siderite. Mining activities have been stopped here in 1857. Very high contents of T-Hg are still found at this site, up to 144 mg kg −1. In most cases we found a statistically significant correlation between T-Hg and Hg 0 values regardless of the pollution source. On the contrary, insignificant correlation was observed neither between T-Hg and GEM values, nor between GEM and Hg 0. Concentrations of the investigated
Water, Air, and Soil Pollution, 2007
This study investigated the influence of soil and air mercury (Hg) concentrations on Hg accumulation in plant components for three plant species, Robinia pseudoacacia (Black locust), Juniperous scopulorum (Juniper), and Artemisia tridentata (Sagebrush), grown in environmentally controlled growth chambers. Exposures included ambient and elevated air (3.1±0.4 and 30.1±3.5 ng m −3 ) and soil (0.06±0.02 and 27.7±6.3 μg g −1 ) Hg concentrations. In addition, foliar Hg fluxes were measured, as was Hg accumulated directly on the leaf surface. Air Hg concentrations were found to be the dominant factor associated with foliar Hg concentrations. Foliar MeHg concentrations of deciduous plant species were greater than evergreen species. Trunk Hg concentrations were influenced by air and soil Hg concentrations. Root Hg concentrations were directly correlated with soil Hg concentrations. Foliar Hg fluxes for R. pseudoacacia were predominantly deposition. For A. tridentata foliar Hg fluxes were bi-directional, and foliar fluxes measured for J. scopulorum were not statistically different from the blank chamber fluxes. Measured fluxes did not correspond well with predicted uptake based on foliar Hg concentrations.
Atmospheric Environment, 2011
Uptake of gaseous elemental mercury (Hg 0 (g)) by three plant species and two soil types was measured using mercury vapor enriched in the 198 isotope (198 Hg 0 (g)). The plant species and soil types were: White Ash (Fraxinus Americana; WA); White Spruce (Picea Glauca; WS); Kentucky Bluegrass (Poa Partensis; KYBG); Plano Silt Loam (4% organic matter; PSL); and Plainfield Sand/Sparta Loamy Sand (1.25e1.5% organic matter: PS). The plants and soils were exposed to isotopically enriched Hg 0 (g) in a 19 m 3 controlled environment room for 7 days under optimal plant growth conditions (20 C, 140 Wm À2 between 300 nm and 700 nm; 70% RH) and atmospherically relevant Hg 0 (g) concentrations. Mercury was recovered from the samples using acidic digestions and surface leaches, and then analyzed for enrichments in 198 Hg by ICPMS. The method was sensitivity enough that statistically significant enrichments in 198 Hg were measured in the plant foliage at the end of Day 1. Whole leaf digestions and surface-selective leaches revealed that accumulative uptake was predominantly to the interior of the leaf under the conditions studied. Uptake fluxes for WA increased between the first and third days and remained constant thereafter (WA; Day 1 ¼ 7 AE 2 Â 10 À5 ng m À2 s À1 ; Days 3e7 ¼ 1.3 AE 0.1 Â 10 À4 ng m À2 s À1 ; where m 2 refers to one sided leaf area). KYBG demonstrated similar behavior although no Day 3 measurement was available (Day 1 ¼ 7.5 AE 0.5 Â 10 À5 ng m À2 s À1 ; Day 7 ¼ 1.2 AE 0.1 Â 10 À4 ng m À2 s À1). Fluxes to White Spruce were lower, with little difference between Days 1 and 3 followed by a decrease at Day 7 (WS; Days 1e3 ¼ 5 AE 2 Â 10 À5 ng m À2 s À1 ; Day 7 ¼ 2.4 AE 0.2 Â 10 À5 ng m À2 s À1). Uptake of Hg to soils was below the method detection limit for those media (PSL ¼ 3 Â 10 À2 ng m À2 s À1 ; PS ¼ 3 Â 10 À3 ng m À2 s À1) over the 7 day study period. Foliar resistances calculated for each species compared well to previous studies.