Environmental Risk Assessment of Produced Water Discharges on the Dutch Continental Shelf

The OSPAR Offshore Industry Committee (OIC) has decided, in its meeting of 2008, to evaluate the possibility of implementing a risk based approach towards produced water management. Currently, Norway has made most progress in this field as it has fully implemented the Environmental Impact Factor as the basis of their biannual reporting obligations. The Netherlands has for as yet mainly followed a source (immission) based approach, and therefore did not adopt a specific risk based approach. In this study an overview is provided of current approaches to assess the ecological risk of produced water discharges and it is investigated how these approaches can be used in the Dutch situation for produced water management as intended by the OIC

Addressing Uncertainty in TMDLS: Short Course at Arkansas Water Resources Center 2001 Annual Conference

Management of a critical natural resource like water requires information on the status of that resource. The US Environmental Protection Agency (EPA) reported in the 1998 National Water Quality Inventory that more than 291,000 miles of assessed rivers and streams and 5 million acres of lakes do not meet State water quality standards. This inventory represents a compilation of State assessments of 840,000 miles of rivers and 17.4 million acres of lakes; a 22 percent increase in river miles and 4 percent increase in lake acres over their 1996 reports. Siltation, bacteria, nutrients and metals were the leading pollutants of impaired waters, according to EPA. The sources of these pollutants were presumed to be runoff from agricultural lands and urban areas. EPA suggests that the majority of Americans-over 218 million-live within ten miles of a polluted waterbody. This seems to contradict the recent proclamations of the success of the Clean Water Act, the Nation\u27s water pollution control law. EPA also claims that, while water quality is still threatened in the US, the amount of water safe for fishing and swimming has doubled since 1972, and that the number of people served by sewage treatment plants has more than doubled

The UK risk assessment scheme for all non-native species

1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa. 2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored. 3. Although designed for the UK, the scheme can readily be applied elsewhere

Recent developments in the application of risk analysis to waste technologies.

The European waste sector is undergoing a period of unprecedented change driven by business consolidation, new legislation and heightened public and government scrutiny. One feature is the transition of the sector towards a process industry with increased pre-treatment of wastes prior to the disposal of residues and the co-location of technologies at single sites, often also for resource recovery and residuals management. Waste technologies such as in-vessel composting, the thermal treatment of clinical waste, the stabilisation of hazardous wastes, biomass gasification, sludge combustion and the use of wastes as fuel, present operators and regulators with new challenges as to their safe and environmentally responsible operation. A second feature of recent change is an increased regulatory emphasis on public and ecosystem health and the need for assessments of risk to and from waste installations. Public confidence in waste management, secured in part through enforcement of the planning and permitting regimes and sound operational performance, is central to establishing the infrastructure of new waste technologies. Well-informed risk management plays a critical role. We discuss recent developments in risk analysis within the sector and the future needs of risk analysis that are required to respond to the new waste and resource management agenda

Contributions to predicting contaminant leaching from secondary materials used in roads

Slags, coal ashes, and other secondary materials can be used in road construction. Both traditional and secondary materials used in roads may contain contaminants that may leach and pollute the groundwater. The goal of this research was to further the understanding of leaching and transport of contaminants from pavement materials. Towards this goal, a new probabilistic framework was introduced which provided a structured guidance for selecting the appropriate model, incorporating uncertainty, variability, and expert opinion, and interpreting results for decision making. In addition to the framework, specific contributions were made in pavement and embankment hydrology and reactive transport, Bayesian statistics, and aqueous geochemistry of leaching. Contributions on water movement and reactive transport in highways included probabilistic prediction of leaching in an embankment, and scenario analyses of leaching and transport in pavements using HYDRUS2D, a contaminant fate and transport model. Water flow in a Minnesota highway embankment was replicated by Bayesian calibration of hydrological parameters against water content data. Extent of leaching of Cd from a coal fly ash was estimated. Two dimensional simulations of various scenarios showed that salts in the base layer of pavements are depleted within the first year whereas the metals may never reach the groundwater if the pavement is built on adsorbing soils. Aqueous concentrations immediately above the groundwater estimated for intact and damaged pavements can be used for regulators to determine the acceptability of various recycled materials. Contributions in the aqueous geochemistry of leaching included a new modeling approach for leaching of anions and cations from complex matrices such as weathered steel slag. The novelty of the method was its simultaneous inclusion of sorption and solubility controls for multiple analytes. The developed model showed that leaching of SO4, Cr, As, Si, Ca, Mg, and V were controlled by corresponding soluble solids. Leaching of Pb was controlled by Pb(VO4)3 solubility at low pHs and by surface precipitation reactions at high pHs. Leaching of Cd and Zn were controlled by surface complexation and surface precipitation, respectively

Development And Application Of A Methodology To Estimate Regional Natural Conditions For Trace Metals In Marine Sediments Of Southcentral Alaska's Coastal Region

Thesis (Ph.D.) University of Alaska Fairbanks, 2010Increasing levels of resource development and population growth along Alaska's relatively pristine coastline require responsible environmental stewardship that is based on scientifically defensible monitoring and assessment. This thesis develops a methodology to assess the spatial distribution of coastal sediment trace metals and estimate their natural condition along Alaska's coastline. Marine sediments provide a better integrated long-term signal for naturally occurring and anthropogenic chemicals than repeated water measurements. The first of three manuscripts reports on marine sediment trace metal concentrations from a probabilistic sampling survey of Alaska's Southcentral coastal region. Results are described on a proportional basis, i.e., percent of estuary area, for the distribution of As, Cd, Cr, Cu, Pb, Hg, Ni, Ag, and Zn in the sediments. With the exception of naturally elevated Cr and Ni at a site bounded by a chromite ore body, sediment trace metal concentrations measured represent non-analmous levels. The second manuscript develops natural conditions for fluvial trace metal inputs from two major Southeast Alaska coastal watersheds: Cook Inlet and Copper River. The stream sediment trace metal natural conditions place levels in the adjacent coastal sediments into context. Two exploratory data analysis techniques, the Tukey Box plot and Median + 2 Median Absolute Deviation, combined with geochemical mapping are used to develop stream sediment trace metal natural conditions. The third manuscript builds on the first two to develop a methodology to estimate coastal sediment natural conditions. Population estimates for the cumulative area 90% UCB 95% sediment trace metal of interest obtained from the sampling survey methodology and screened reference sites is used to establishing an upper threshold value for regional natural conditions. While this work establishes natural condition marine sediment trace metal levels for this region, the significance of these levels from an ecotoxciological perspective remains to be established. Additional studies are needed along other sections of Alaska's coastline, coupled with biological assessments, if Alaska is to develop relevant sediment quality guidelines

Global sensitivity analysis in hydrological modeling: Review of concepts, methods, theoretical framework, and applications

Sensitivity analysis (SA) aims to identify the key parameters that affect model performance and it plays important roles in model parameterization, calibration, optimization, and uncertainty quantification. However, the increasing complexity of hydrological models means that a large number of parameters need to be estimated. To better understand how these complex models work, efficient SA methods should be applied before the application of hydrological modeling. This study provides a comprehensive review of global SA methods in the field of hydrological modeling. The common definitions of SA and the typical categories of SA methods are described. A wide variety of global SA methods have been introduced to provide a more efficient evaluation framework for hydrological modeling. We review, analyze, and categorize research into global SA methods and their applications, with an emphasis on the research accomplished in the hydrological modeling field. The advantages and disadvantages are also discussed and summarized. An application framework and the typical practical steps involved in SA for hydrological modeling are outlined. Further discussions cover several important and often overlooked topics, including the relationship between parameter identification, uncertainty analysis, and optimization in hydrological modeling, how to deal with correlated parameters, and time-varying SA. Finally, some conclusions and guidance recommendations on SA in hydrological modeling are provided, as well as a list of important future research directions that may facilitate more robust analyses when assessing hydrological modeling performance

Tsunami Hazard Assessment: Best Modeling Practices and State-of-the-Art Technology

NUREG/CR-722

Tsunami Hazard Assessment: Best Modeling Practices and State-of-the-Art Technology

NUREG/CR-722