STORRE Collection: Electronic copies of Biological and Environmental Sciences journal articles.Electronic copies of Biological and Environmental Sciences journal articles.http://hdl.handle.net/1893/1232024-03-19T02:44:24Z2024-03-19T02:44:24ZEliciting expert judgements to underpin our understanding of faecal indicator organism loss from septic tank systemsMzyece, Chisha ChongoGlendell, MiriamGagkas, ZisisQuilliam, Richard S.Jones, IanPagaling, EulynAkoumianaki, IoannaNewman, ClaireOliver, David M.http://hdl.handle.net/1893/358562024-03-14T01:04:29Z2024-04-01T00:00:00ZTitle: Eliciting expert judgements to underpin our understanding of faecal indicator organism loss from septic tank systems
Author(s): Mzyece, Chisha Chongo; Glendell, Miriam; Gagkas, Zisis; Quilliam, Richard S.; Jones, Ian; Pagaling, Eulyn; Akoumianaki, Ioanna; Newman, Claire; Oliver, David M.
Abstract: Septic tank systems (STS) in rural catchments represent a potential source of microbial pollution to watercourses; however, data concerning the risk of faecal indicator organism (FIO) export from STS to surface waters are scarce. In the absence of empirical data, elicitation of expert judgements can provide an alternative approach to aid understanding of FIO pollution risk from STS. Our study employed a structured elicitation process using the Sheffield Elicitation Framework to obtain expert judgements on the proportion of FIOs likely to be delivered from STS to watercourses, based on 36 scenarios combining: (i) septic tank effluent movement risk, driven by soil hydro-morphological characteristics; (ii) distance of septic tank to watercourse; and (iii) degree of slope. Experts used the tertile method to elicit a range of values representing their beliefs of the proportion of FIOs likely to be delivered to a watercourse for each scenario. The experts judged that 93 % of FIOs would likely be delivered from an STS to a watercourse under the highest risk scenario that combined (i) very high STS effluent movement risk, (ii) STS distance to watercourse <10 m, and (iii) a location on a steep slope with gradient >25 %. Under the lowest risk scenario, the proportion of FIOs reaching a watercourse would likely reduce to 5 %. Expert confidence was high for scenarios that represented extremes of risk, while uncertainty increased for scenarios depicting intermediate risk conditions. The behavioural aggregation process employed to obtain a consensus among the experts proved to be useful for highlighting both areas of strong consensus and high uncertainty. The latter therefore represent priorities for future empirical research to further improve our understanding of potential pollution risk from septic tanks and in turn enable better assessments of potential threats to water quality in rural catchments throughout the world where decentralised wastewater systems are common.2024-04-01T00:00:00ZUrban landscapes and legacy industry provide hotspots for riverine greenhouse gases: A source-to-sea study of the River ClydeBrown, Alison MBass, Adrian MSkiba, UteMacdonald, John MPickard, Amy Ehttp://hdl.handle.net/1893/357802024-02-28T01:01:46Z2023-06-01T00:00:00ZTitle: Urban landscapes and legacy industry provide hotspots for riverine greenhouse gases: A source-to-sea study of the River Clyde
Author(s): Brown, Alison M; Bass, Adrian M; Skiba, Ute; Macdonald, John M; Pickard, Amy E
Abstract: There is growing global concern that greenhouse gas (GHG) emissions from water bodies are increasing because of interactions between nutrient levels and climate warming. This paper investigates key land-cover, seasonal and hydrological controls of GHGs by comparison of the semi-natural, agricultural and urban environments in a detailed source-to-sea study of the River Clyde, Scotland. Riverine GHG concentrations were consistently oversaturated with respect to the atmosphere. High riverine concentrations of methane (CH 4) were primarily associated with point source inflows from urban wastewater treatment, abandoned coal mines and lakes, with CH 4-C concentrations between 0.1-44 µg l 1. Concentrations of carbon dioxide (CO 2) and nitrous oxide (N 2 O) were mainly driven by nitrogen concentrations, dominated by diffuse agricultural inputs in the upper catchment and supplemented by point source inputs from urban wastewater in the lower urban catchment, with CO 2-C concentrations between 0.1-2.6 mg l 1 and N 2 ON concentrations between 0.3-3.4 µg l 1. A significant and disproportionate increase in all GHGs occurred in the lower urban riverine environment in the summer, compared to the semi-natural environment, where GHG concentrations were higher in winter. This increase and change in GHG seasonal patterns points to anthropogenic impacts on microbial communities. The loss of total dissolved carbon, to the estuary is approximately 48.4 ± 3.6 Gg C yr 1 , with the annual inorganic carbon export approximately double that of organic carbon and four times that of CO 2, with CH 4 accounting for 0.03%, with the anthropogenic impact of disused coal mines accelerating DIC loss. The annual loss of total dissolved nitrogen to the estuary is approximately 4.03 ± 0.38 Gg N yr 1 of which N 2 O represents 0.06%. This study improves our understanding of riverine GHG generation and dynamics which can contribute to our knowledge of their release to the atmosphere. It identifies where action could support reductions in aquatic GHG generation and emission.2023-06-01T00:00:00ZAnthropogenic-estuarine interactions cause disproportionate greenhouse gas production: A review of the evidence baseBrown, Alison MBass, Adrian MPickard, Amy Ehttp://hdl.handle.net/1893/357792024-02-28T01:01:16Z2022-01-01T00:00:00ZTitle: Anthropogenic-estuarine interactions cause disproportionate greenhouse gas production: A review of the evidence base
Author(s): Brown, Alison M; Bass, Adrian M; Pickard, Amy E
Abstract: Biologically productive regions such as estuaries and coastal areas, even though they only cover a small percentage of the world's oceans, contribute significantly to methane and nitrous oxide emissions. This paper synthesises greenhouse gas data measured in UK estuary studies, highlighting that urban wastewater loading is significantly correlated with both methane (P < 0.001) and nitrous oxide (P < 0.005) concentrations. It demonstrates that specific estuary typologies render them more sensitive to anthropogenic influences on greenhouse gas production, particularly estuaries that experience low oxygen levels due to reduced mixing and stratification or high sediment oxygen demand. Significantly, we find that estuaries with high urban wastewater loading may be hidden sources of greenhouse gases globally. Synthesising available information, a conceptual model for greenhouse gas concentrations in estuaries with different morphologies and mixing regimes is presented. Applications of this model should help identification of estuaries susceptible to anthropogenic impacts and potential hotspots for greenhouse gas emissions.2022-01-01T00:00:00ZSources and controls of greenhouse gases and heavy metals in mine water: A continuing climate legacyBrown, AlisonBass, AdrianGarnett, MarkSkiba, UtePickard, Amyhttp://hdl.handle.net/1893/357782024-02-28T01:00:49Z2024-01-01T00:00:00ZTitle: Sources and controls of greenhouse gases and heavy metals in mine water: A continuing climate legacy
Author(s): Brown, Alison; Bass, Adrian; Garnett, Mark; Skiba, Ute; Pickard, Amy
Abstract: Water pollution arising from abandoned coal mines, is second only to sewage as a source of freshwater pollution and in coalfield catchments mine water can be the dominant pollutant, with oxidised iron smothering the bed of receiving rivers. This study measured greenhouse gases in mine water outflows from sixteen sites across the Midland Valley in Scotland. Radiogenic and stable carbon isotopes measurements (Δ14C and δ13C) were used to determine the sources of both methane (CH4) and carbon dioxide (CO2) produced within the flooded mine environment. Concentrations of CH4-C ranged from 20 to 215 μg l− 1 and CO2-C from 30 to 120 mg l− 1, with CO2 accounting for 97 % of the mine water global warming potential. Methane origins included 51 % modern biogenic, 41 % thermogenic and 8 % from hydrogenotrophic methanogenesis of coal. The most significant in verse impact on biogenic CH4 concentrations was sulphate, most likely due to sulphate reducing bacteria out competing methanogens. Carbon dioxide origins included 64 % from the dissolution of limestone, 21 % from terrestrial organic carbon and 15 % from coal. The limestone derived CO2 was positively correlated with high sulphate concentrations, which resulted in sulphuric acid and caused the dissolution of carbonate from lime stone. The mine waters experienced significant carbonate buffering becoming only slightly acidic (pH 6–7), but with significant loss of inorganic carbon. The mine waters had low dissolved oxygen (6–25 %) and high dissolved iron (2 to 65 mg l − 1) and manganese (0.5 to 5 mg l− 1) concentrations. Dissolved greenhouse gases from abandoned mines were estimated as 0.27 +0.31 − 0.18 % of Scotland's global warming potential. This novel work has contributed information about the sources and controls of greenhouse gas fluxes in mine waters and identified the need to quantify and report this emissions term.2024-01-01T00:00:00Z