Soil organic carbon (SOC) is the largest carbon pool in terrestrial ecosystems, which plays an important role in climate change by regulating atmospheric carbon dioxide. Sweden’s forest management has led to a decrease in old growth forests. This change in land use can affect SOC levels in these forests. This report quantified SOC stocks among different wetness classes in 10 old growth forests across multiple regional environmental gradients in Sweden. I tested for the effects of some different environmental factors on SOC: temperature, precipitation, altitude, stem basal area, latitude, and normalized difference vegetation index. Soil measurements were taken from three different horizons: the O-, E-, and B-horizon. The results showed that the mean SOC stock in old growth forests (5.25 ± 0.60 kg m-2)  is a bit higher than the regional average (4.1 ± 0.5 kg m-2) and that local variation within forests, mainly due to hydrology, appears to drive variation that is often as big or larger than regional variations. There were no significant differences between the different forests, but there were significant differences found between the different wetness classes. There were several correlations found between the different regional environmental factors and SOC stocks. The most prominent relationship was a positive link between the O-horizons’ SOC stocks and temperature (R2adj = 0.58). Overall, these results indicate that SOC stocks in old growth forests are affected by both soil wetness at a local scale and air temperature at a regional scale; and that they might contain a slightly larger amount of SOC than managed forests.

There are several incentives for using bottom ash from municipal solid waste incineration (MSWI bottom ash) as a construction material, such as for road construction. These incentives include decreased disposal of material on landfills and a reduced amount of raw material extracted for road building purposes. However, one of the main obstacles to utilising the material is uncertainties regarding its environmental properties. The overall objective of this thesis is to describe the potential environmental impacts of utilising MSWI bottom ash in constructions and to improve the tools for environmental assessments. An environmental systems analysis (ESA) approach based on a life cycle perspective was outlined and used in a case study, with the aim of describing the differences in resource use and emissions that can be expected if crushed rock in the sub-base of a road in the Stockholm region in Sweden were to be substituted by MSWI bottom ash. The whole life cycle of the road was taken into account and the alternative disposal of the bottom ash was included. It was found that the studied alternatives would cause different types of potential environmental impact; whereas the conventional alternative with only crushed rock in the road’s sub-base would lead to larger use of energy and natural resources, the alternative with MSWI bottom ash in the sub-base would lead to larger contaminant leaching. It was concluded that a life cycle approach is needed in order to include both resource use and emissions in the comparison between the two alternative scenarios. The leaching of metals turned out to be the most important environmental aspect for the comparison and in particular the difference in copper (Cu) leaching was shown to be large. However, a large amount of Cu may not pose an environmental threat if the Cu is strongly bound to dissolved organic carbon (DOC). In order to improve the basis for toxicity estimates and environmental risk assessments, and thereby provide better input values for ESAs, the speciation of Cu to DOC in MSWI bottom ash leachate was studied. It was found that Cu to a large extent was bound to DOC, which is consistent with previous research. The results also suggest that the hydrophilic fraction of the MSWI bottom ash DOC is important for Cu complexation and that the pH-dependence for Cu complexation to MSWI bottom ash DOC is smaller than for natural DOC. This implies that models calibrated for natural DOC may give inconsistent simulations of Cu-DOC complexation in MSWI bottom ash leachate. / QC 20101217

Farmers have been disrupting the carbon cycle ever since humans started converting forests to agricultural lands. But are there farming practices that can be applied to increase the carbon storage in the soil and subsequently counteract increasing carbon dioxide levels in the atmosphere? In this study I investigate if soil organic matter (SOM) and soil organic carbon (SOC) change with longer interruption between tillage events. The study was conducted by studying SOM concentrations and SOC pools in eight fields with different time since tillage (1 to 14 years). I found that SOM concentrations increased in the O horizon of the studied soil in response to increased time since tillage. Here, SOM concentrations were on average around 13 % one year after tillage, while fourteen-year-old farmland had a concentration around 15 %. In similar, SOC pool increased from around 0.1 kg C m-2 in the O horizon of 1 year old soil to 0.33 kg C m-2 14 years after tillage. While both SOM concentrations and SOC pools increased in the O horizon over time since tillage, the SOM concentration and SOC pools decreased in the subsoil. I found no net sequestering of SOC in response to less frequent tillage in comparison to more frequency tillage. My conclusion is that limiting tillage to 14-year cycles is not enough to increase carbon sequestration.

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Ferrate (VI) has been studied as an alternative chemical to disinfect water and wastewater in recent years. The disinfection effectiveness of two different wet oxidation ferrate (VI) synthesis formulas in wastewater and Econlockhatchee River water was evaluated. Ferrate (VI) is synthesized by addition of ferric chloride to a mixture of sodium hydroxide and calcium hypochlorite (refer to U.S. Patent 6,790,429). One ferrate (VI) synthesis formula uses below the stoichiometric requirement of hypochlorite (Low Chlorine Formula) while the other ferrate (VI) synthesis formula uses more than the stoichiometric requirement of hypochlorite (Standard Chlorine Formula). For applications requiring low chlorine residual effluent quality, the Low Chlorine Formula intuitively is a more suitable disinfectant than the Standard Formula. For applications where chlorine residual is of little or no significance, the Standard Formula is logically a more suitable disinfectant due to lower production cost and production of higher ferrate (VI) concentrations than the Low Chlorine Formula. The total chlorine concentration, unfiltered and filtered ferrate (VI) concentration, and dissolved organic carbon concentration before and after treatment using both ferrate (VI) formulas in wastewater and Econ River water was measured at a contact time of 30 minutes. Disinfection capabilities were measured by comparing the quantity of Heterotrophic bacteria, Total Coliform, Escherichia coli, and Enterococcus bacteria pre-ferrate (VI) to post-ferrate (VI) at dosages of 2, 4, and 7.5 mg/L as ferrate (VI) using both ferrate (VI) formulas. The rate of disappearance of both ferrate (VI) formulas in wastewater at an unadjusted pH and pH of 6.0-6.35 was determined. In addition the total oxidant absorbance and total chlorine concentration were measured over a 30-minute period. Both ferrate (VI) formulas were effective at inactivating Total Coliform, E. Coli, Enterococcus, and heterotrophic bacteria at a 30-minute contact time and lowering DOC concentrations in Econlockhatchee River water and secondary wastewater. The Standard Formula demonstrated better disinfection at lower dosages than the Low Chlorine Formula. In both ferrate (VI) formulas, there was a presence of an instantaneous demand of ferrate (VI) and a first-order reaction rate of ferrate (VI) over 30 minutes. The chlorine residual of 7.5 mg/L ferrate (VI) dose in wastewater at a 30-minute contact time was 0.2 to 0.6 mg/L Cl2 for the Low Chlorine Formula and 0.8 to 1.4 mg/L Cl2 for the Standard Formula. These experiments indicate that both ferrate (VI) formulas can serve as effective environmentally friendly disinfectants for wastewater and Econ River water.

No / Organic matter (OM) causes many problems in drinking water treatment. It is difficult to monitor OM concentrations and character during treatment processes due to its complexity. Fluorescence spectroscopy is a promising tool for online monitoring. In this study, a unique dataset of fluorescence excitation emission matrixes (EEMs) (n = 867) was collected from all treatment stages of five drinking water treatment plants (WTPs) situated in diverse locations from subtropical to temperate climate. The WTPs incorporated various water sources, treatment processes and OM removal efficiencies (DOC removal 0%–68%). Despite these differences, four common fluorescence PARAFAC components were identified for characterisation of OM concentration and treatability. Moreover, fluorescence component ratios showed site-specific statistically significant correlations with OM removal, which contrasted with correlations between specific UV absorbance at 254 nm (SUVA) and OM removal that were not statistically significant. This indicates that use of fluorescence spectroscopy may be a more robust alternative for predicting DOC removal than UV spectroscopy. Based on the identified fluorescence components, four optical locations were selected in order to move towards single wavelength online OM monitoring.

Antihistamines are a group of pharmaceuticals that enter the environment and may affect microorganisms that regulate decomposing of organic matter and the release of carbon and nitrogen from soils. In this study I investigated if the antihistamine fexofenadine decreases the concentration of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from humus. I used humus from two vegetation types (heath and meadow), and used a batch experiment approach, where humus was mixed with fexofenadine solutions (2000 ng/L and 20 000 ng/L). After ten days in room temperature, the samples with fexofenadine were compared with batches containing pure water solutions (control). I found differences in the concentration of DOC, DON and pH that were dependent on the studied vegetation types. There were higher concentrations of DOC and DON in heath (35.9 mg/L and 2.0 mg/L) than in the more nutrient rich meadow (9.2 mg/L and 0.5 mg/L). The latter vegetation type did also have a higher pH. In contrast to my hypothesis, the concentration of DOC and DON was not significantly affected by the fexofenadine. However, if considering a 90%-level of significance, there were a significant interaction effect where concentration of DOC decreased in meadow and increased it in heath. A possible vegetation specific effect of fexofenadin seems plausible as microbial biomass and activity in the vegetation types are known to differ. My findings cannot exclude that fexofenadine stimulates degradation of DOC in the more microbial active meadow humus, but not in the humus of heath where activities are lower.

Snowmelt river systems exhibit seasonal fluxes in water chemistry, potentially affecting the water supply of one-sixth of the worlds population. In this study, we examined water chemistry of the upper Provo River, northern Utah, which supplies water to over two million people along the urban Wasatch Front. Seasonal changes in water chemistry were characterized by analyzing discharge and dissolved organic carbon (DOC) with dissolved trace metal and cation concentrations (La, Pb, Cu, Al, Be, Sr and K) over three consecutive water years 20142016, with intensive sampling during snowmelt runoff. To better understand links between metal movement and DOC, we sampled the river in three locations (Soapstone, Woodland, and Hailstone), snowpack, and ephemeral snowmelt channels. Concentrations of La, Pb, Cu, Al, and Be increased with discharge/snowmelt during the 2014, 2015 and 2016 water years. Over 90% of La, Pb, Cu, Al, Be and between 70-90% Sr and K loads occurred during the snowmelt season (April-June). In relation to discharge, concentrations of each element varied between the river sampling sites. At Soapstone, DOC, La, Pb, Cu, Al and Be increased slightly with discharge, but Sr and K remained chemostatic. At Woodland and Hailstone, DOC, La, Pb, Cu, Al and Be had sharp increases with discharge, and Sr and K were diluted. Hysteresis patterns showed that concentrations of DOC, La, Pb, Cu, Al, Be, Sr and K all peaked on the rising limb of the hydrograph at the higher elevation Soapstone site but patterns were variable at the lower elevation Woodland and Hailstone sites. Concentrations for ephemeral channels were significantly higher than river and snow concentrations in La, Pb, Cu and Al, suggesting soil water was a significant source of flushed metals and DOC to the upper Provo River. DOC was highly correlated with La (R2 = 0.94, P = < .0001), Pb (R2 = 0.76, P = < .0023), Cu (R2 = 0.83, P = < .0001), Al (R2 = 0.94, P = < .0001) and Be (R2 = 0.93, P = < .0005), and likely facilitating metal transport. More work is needed to determine the mechanisms of DOC and metal transport, and potential metal complexation. This study has implications for understanding water quality impacts from metal flushing during snowmelt in mountain watersheds.