An evaluation of biotic ligand models predicting acute copper toxicity to Daphnia magna in wastewater effluent

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 SETAC.The toxicity of Cu to Daphnia magna was investigated in a series of 48-h immobilization assays in effluents from four wastewater treatment works. The assay results were compared with median effective concentration (EC50) forecasts produced by the HydroQual biotic ligand model (BLM), the refined D. magna BLM, and a modified BLM that was constructed by integrating the refined D. magna biotic ligand characterization with the Windermere humic aqueous model (WHAM) VI geochemical speciation model, which also accommodated additional effluent characteristics as model inputs. The results demonstrated that all the BLMs were capable of predicting toxicity by within a factor of two, and that the modified BLM produced the most accurate toxicity forecasts. The refined D. magna BLM offered the most robust assessment of toxicity in that it was not reliant on the inclusion of effluent characteristics or optimization of the dissolved organic carbon active fraction to produce forecasts that were accurate by within a factor of two. The results also suggested that the biotic ligand stability constant for Na may be a poor approximation of the mechanisms governing the influence of Na where concentrations exceed the range within which the biotic ligand stability constant value had been determined. These findings support the use of BLMs for the establishment of site-specific water quality standards in waters that contain a substantial amount of wastewater effluent, but reinforces the need for regulators to scrutinize the composition of models, their thermodynamic and biotic ligand parameters, and the limitations of those parameters.EPSRC and Severn Trent Water

Realizing live sequence charts in SystemVerilog.

The design of an embedded control system starts with an investigation of properties and behaviors of the process evolving within its environment, and an analysis of the requirement for its safety performance. In early stages, system requirements are often specified as scenarios of behavior using sequence charts for different use cases. This specification must be precise, intuitive and expressive enough to capture different aspects of embedded control systems. As a rather rich and useful extension to the classical message sequence charts, live sequence charts (LSC), which provide a rich collection of constructs for specifying both possible and mandatory behaviors, are very suitable for designing an embedded control system. However, it is not a trivial task to realize a high-level design model in executable program codes effectively and correctly. This paper tackles the challenging task by providing a mapping algorithm to automatically synthesize SystemVerilog programs from given LSC specifications

Urban planning, public participation and digital technology: App development as a method of generating citizen involvement in local planning processes

There has been a recent shift in England towards empowering citizens to shape their neighbourhoods. However, current methods of participation are unsuitable or unwieldy for many people. In this paper, we report on ChangeExplorer, a smart watch application to support citizen feedback, to investigate the extent to which digital wearables can address barriers to participation in planning. The research contributes to both technology-mediated citizen involvement and urban planning participation methods. The app leverages in-situ, quick interactions encouraging citizens to reflect and comment on their environment. Taking a case study approach, the paper discusses the design and deployment of the app in a local planning authority through interviews with 19 citizens and three professional planners. The paper discusses the potential of the ChangeExplorer app to address more conceptual issues, and concludes by assessing the degree to which the technology raises awareness of urban change and whether it could serve as a gateway to more meaningful participatory methods

Geographically weighted correspondence matrices for local error reporting and change analyses: mapping the spatial distribution of errors and change

This letter describes and applies generic methods for generating local measures from the correspondence table. These were developed by integrating the functionality of two existing R packages: gwxtab and diffeR. They demonstrate how spatially explicit accuracy and error measures can be generated from local geographically weighted correspondence matrices, for example to compare classified and reference data (predicted and observed) for error analyses, and classes at times t1 and t2 for change analyses. The approaches in this letter extend earlier work that considered the measures derived from correspondence matrices in the context of generalized linear models and probability. Here the methods compute local, geographically weighted correspondence matrices, from which local statistics are directly calculated. In this case a selection of the overall and categorical difference measures proposed by Pontius and Milones (2011) and Pontius and Santacruz (2014), as well as spatially distributed estimates of kappa coefficients, User and Producer accuracies. The discussion reflects on the use of the correspondence matrix in remote sensing research, the philosophical underpinnings of local rather than global approaches for modelling landscape processes and the potential for policy and scientific benefits that local approaches support

Potential for low-emissions oil palm production in Indonesia: insights from spatiotemporal dynamics

Rising global demand for palm oil has created environmental pressures related to deforestation, burning, and peat exploitation, which in turn drives increased greenhouse gas (GHG) emissions. GHG emissions in oil palm (OP) production are known to vary spatially. However, temporal changes across contrasting management and soil types, are less well studied. This paper quantifies spatiotemporal GHG emissions across contrasting regions, management types, and soil types for the period 1990–2019 to assess the potential for reducing emission. The study focusses on Indonesia, as the biggest producer of OP, and in particular on the North Sumatra and Riau provinces, where OP is intensively produced. GHG inventories in 5 year time steps were constructed to investigate the change in drivers of emissions using spatial data, resampled to a 500 m grid. Total GHG emissions were found to have increased in both regions due to expanding OP production. However, results show a reduction in emissions flux from 1.98 to 1.15 Ton Ceq. ha−1yr−1 in North Sumatra and 9.63–2.67 Ton Ceq. ha−1yr−1 in Riau over the study period. This reduced flux was linked to the decreased deforestation and burning activities, together with increased biomass increment from lower carbon stock area conversion to OP. In both provinces, smallholder plantations emitted fewer emissions than industrial ones, and production on organic soils resulted in consistently higher emissions than on mineral soils. In North Sumatra, emissions under all management and soil types were found to decrease. In Riau, however, GHG emissions on organic soils regardless of management types, remained high. Our findings emphasise that potential for low-emissions OP production is attainable by reducing emissions per unit area through an improved understanding of GHG emissions spatiotemporal variability and their drivers. These contribute to reinforcing ongoing government regulations and guiding the industry towards low-emission OP productions

Proposed Environmental Quality Standards for Phenol in Water

This is the Proposed Environmental Quality Standards (EQS) for Phenol in Water prepared for the National Rivers Authority, and published by the Environment Agency in 1995. The report reviews the properties and uses of phenol, its fate, behaviour and reported concentrations in the environment and critically assesses the available data on its toxicity and bioaccumulation. The information is used to derive EQSs for the protection of fresh and saltwater life and for the abstraction of water to potable supply. Phenol is widely used as a chemical intermediate and the main sources for phenol in the environment are of anthropogenic origin. Phenol may also be formed during natural decomposition of organic material. The persistence of phenol in the aquatic environment is low with biodegradation being the main degradation process (half-lives of hours to days). Phenol is moderately toxic to aquatic organisms and its potential to bioaccumulate in aquatic organisms is low

Domestic source of phosphorus to sewage treatment works.

Phosphorus is an element essential for life. Concerns regarding long-term security of supply and issues related to eutrophication of surface waters once released into the aquatic environment have led governments to consider and apply measures for reducing the use and discharge of phosphorus. Examples of source control include legislation to reduce phosphorus use in domestic detergents. This research shows that other domestic sources of phosphorus also contribute significantly to the domestic load to sewer and that overall, domestic sources dominate loads to sewage treatment works. Estimates provided here show that although the natural diet contributes 40% of the domestic phosphorus load, other potentially preventable sources contribute significantly to the estimated 44,000 tonnes of phosphorus entering UK sewage treatment works each year. In the UK, food additives are estimated to contribute 29% of the domestic load; automatic dishwashing detergents contribute 9% and potentially increasing; domestic laundry 14%, including contributions from phosphonates, but decreasing; phosphorus dosing to reduce lead levels in tap water 6%; food waste disposed of down the drain 1%; and personal care products 1%. Although UK data is presented here, it is anticipated that similar impacts would be expected for other developed economies. Consideration of alternatives to all preventable sources of phosphorus from these sources would therefore offer potentially significant reductions in phosphorus loads to sewage treatment works and hence to the aquatic environment. Combining all source control measures and applying them to their maximum extent could potentially lead to the prevention of over 22,000 tonnes-P/year entering sewage treatment works

Pharmaceuticals in soils of lower income countries: Physico-chemical fate and risks from wastewater irrigation.

Population growth, increasing affluence, and greater access to medicines have led to an increase in active pharmaceutical ingredients (APIs) entering sewerage networks. In areas with high wastewater reuse, residual quantities of APIs may enter soils via irrigation with treated, partially treated, or untreated wastewater and sludge. Wastewater used for irrigation is currently not included in chemical environmental risk assessments and requires further consideration in areas with high water reuse. This study critically assesses the contemporary understanding of the occurrence and fate of APIs in soils of low and lower-middle income countries (LLMIC) in order to contribute to the development of risk assessments for APIs in LLMIC. The physico-chemical properties of APIs and soils vary greatly globally, impacting on API fate, bioaccumulation and toxicity. The impact of pH, clay and organic matter on the fate of organic ionisable compounds is discussed in detail. This study highlights the occurrence and the partitioning and degradation coefficients for APIs in soil:porewater systems, API usage data in LLMICS and removal rates (where used) within sewage treatment plants as key areas where data are required in order to inform robust environmental risk assessment methodologies

Shoreline Response to Relative Sea Level Change: Culbin Sands, Northeast Scotland

The aims of this research are to establish shoreline responses to relative sea level change in the Moray Firth. Using both the sea level history and contemporary coastal sediment budgets, a "palaeosediment budget" is presented, which is used to assess the response of the shoreline to changing conditions of relative sea level and sediment supply during the Holocene. The area around Culbin and Burghead Bay in NE Scotland comprises a series of relict shoreline and associated unconsolidated deposits which have formed since the last glacial maximum ca. 18 000 years ago. The Culbin foreland is composed of a suite of shingle storm beach ridges abandoned at up to 3 km inland. The storm ridges were deposited under falling relative sea level after the peak of the Holocene sea level maximum ca. 6500 BP as a staircase of features between 11 and 3 m OD, and are backed landwards by fine grained sediments which have been deposited in their lee. Using modern analogues from The Bar, a barrier beach 3 km downdrift, these are successfully used in conjunction with more standard dated indicators in the reconstruction of relative sea level trends for the area. Detailed morphological investigation of the shingle ridges demonstrates relationships between crest spacing and the regularity of sediment supply, which demonstrate rapid changes in ridge altitude to be directly related to sediment supply, and indirectly related to relative sea level change, An allied study of contemporary processes operating along the Culbin foreshore and at The Bar was also undertaken. Wave data from commercial sources was supplemented by data from a directional wave recorder constructed specifically for the project. Modal wave height and period in the Culbin area are low, at only 1 m and 4 s respectively. The wave recorder demonstrates the under-representation of low (< 0.5 m) waves in commercial records and the presence of converging wave trains. The incidence of swell from the NE sector creates a dominant westerly longshore current, responsible for the strong sediment sorting and drift-aligned landform assemblage at the coast. Tidal currents were found to be very weak in the Culbin area, and are not an important sediment transport mechanism. The primary mode of contemporary foreshore sedimentation has altered radically from a shingle to a sand dominated environment, with shingle now only actively deposited at the proximal end of The Bar. Quantification of the sedimentary inputs and outputs to the Culbin area allowed two sediment budgets to be calculated, one for the sandy Culbin foreshore, and a second shingle budget for The Bar. These both indicate that longshore transport remains the dominant mode of transport, with up to 3.3 x 104 m3 a-1 of sand transported along the Culbin foreshore, and 0.1 x 104 m3 a-1 of shingle along the proximal flank of The Bar. The calculation of a palaeosediment budget aimed to produce a first order quantification of the volumetric development of Culbin during the Holocene period. Adopting a similar methodology as the contemporary sediment budget, the inputs and outputs of sediment to the coastal zone during the Holocene were quantified, although at an order-of-magnitude scale. The supply of shingle from the neighbouring River Findhorn was insufficient to account for the development of Culbin alone, and an additional updrift supply of shingle from the Spey helps to explain the genesis of a composite landform the size of Culbin. A three stage developmental model is proposed, which attempts to explain the variable nature of sediment supply to Culbin under different relative sea levels at Culbin throughout the Holocene. This is based upon the identification of an operational water depth of 6 m around the northern flank of the present Covesea-Burghead area, defining a critical depth below which shingle is no longer actively transported in the nearshore zone. Phase 1 relates to the period 9500-7200 BP, when operational depths were below 6 m, allowing the free passage of shingle from the River Spey to augment the supply from the River Findhorn reaching Culbin. Phase 2 occurs between 7200 and 4300 BP, when operational depths exceeded 6 m and the supply of shingle from the Spey to Culbin was halted. Phase 3 is dated post-4300 BP, when the Spey link was re-established, but shingle supplies were beginning to fail from both rivers. From this, a developmental model is described, which attempts to explain the evolution of the Culbin area under conditions of varying relative sea level and sediment supply. Having considered the past and present evolution of Culbin, an assessment of the future development of the area is made in the light of potentially rising relative sea level as eustatic sea level begins to match the rate of isostatic rebound in the Moray Firth

A Template for a New Generic Geographically Weighted R Package gwverse

GWR is a popular approach for investigating the spatial variation in relationships between response and predictor variables, and critically for investigating and understanding process spatial heterogeneity. The geographically weighted (GW) framework is increasingly used to accommodate different types of models and analyses, reflecting a wider desire to explore spatial variation in model parameters and outputs. However, the growth in the use of GWR and different GW models has only been partially supported by package development in both R and Python, the major coding environments for spatial analysis. The result is that refinements have been inconsistently included within GWR and GW functions in any given package. This paper outlines the structure of a new gwverse package, that may over time replace GW model, that takes advantage of recent developments in the composition of complex, integrated packages. It conceptualizes gwverse as having a modular structure, that separates core GW functionality and applications such as GWR. It adopts a function factory approach, in which bespoke functions are created and returned to the user based on user-defined parameters. The paper introduces two demonstrator modules that can be used to undertake GWR and identifies a number of key considerations and next steps