Tone Karin Frost

Ecotoxicological Mechanisms and Models in an Impact Analysis Tool for Oil Spills

In an international collaborative effort, an impact analysis tool is being developed to predict the effect of accidental oil spills on recruitment and production of Atlantic cod (Gadus morhua) in the Barents Sea. The tool consisted of three coupled ecological models that describe (1) plankton biomass dynamics, (2) cod larvae growth, and (3) fish stock dynamics. The discussions from a series of workshops are presented in which variables and parameters of the first two ecological models were listed that may be affected by oil-related compounds. In addition, ecotoxicological algorithms are suggested that may be used to quantify such effects and what the challenges and opportunities are for algorithm parameterization. Based on model exercises described in the literature, survival and individual growth of cod larvae, survival and reproduction of zooplankton, and phytoplankton population growth are denoted as variables and parameters from the ecological models that might be affected in case of an oil spill. Because toxicity databases mostly (67%) contain data for freshwater species in temperate environments, parameterization of the ecotoxicological algorithms describing effects on these endpoints in the subarctic marine environment is not straightforward. Therefore, it is proposed that metadata analyses be used to estimate the sensitivity of subarctic marine species from available databases. To perform such analyses and reduce associated uncertainty and variability, mechanistic models of varying complexity, possibly aided by new experimental data, are proposed. Lastly, examples are given of how seasonality in ecosystems may influence chemical effects, in particular in the subarctic environment. Food availability and length of day were identified as important characteristics as these determine nutritional status and phototoxicity, respectively.

Comparison of the ParTrack mud/cuttings release model with field data based on use of synthetic-based drilling fluids

A model for the calculation of the spreading and deposition of drilling mud and cuttings has been developed. The calculations are based on a Lagrangian particle approach, which means that the properties of the discharge are represented by moving particles in the model domain. The initialization of the particles is based on the output from an Eulerian near-field underwater plume model. In addition, the model applies external current fields for the horizontal advection of the particles. The paper explains details in a comparison made between measured barium concentrations in the sediment and the modeled deposition on the sea floor from the drilling of eight exploration wells and eight production wells for the development of an oil field in the North Sea.

Comparison of the ParTrack mud/cuttings release model with field data

Abstract The oil industry promotes the development of numerical models for prediction of impacts from their discharges to sea. A model for the simulation of the spreading and deposition of drilling mud and cuttings on the sea floor as well as the spreading of chemicals (and small-sized particles) in the water column has been developed. The simulation is based on a Lagrangian ‘particle’ approach, which means that the properties of the discharge are represented by moving ‘particles’ in the model domain. The initialization of the particles is based on the output from an Eulerian near field underwater plume model. In addition, the model applies external current fields for the horizontal advection of the particles. This paper presents a comparison between simulated and measured concentrations of barium (barite) in surface contaminated sediment in the vicinity of an oil production field. As a part of the regular surveillance of oil production sites on the Norwegian Continental Shelf, the barium content in surface sediments is measured. These data might therefore serve as an opportunity for comparing simulation results with measured depositions of barium (barite) on the sea floor. The paper explains details in the comparison made between the measured barium concentrations in the sediment and the simulated deposition on the sea floor from the drilling of three exploration wells and 18 production wells off the west coast of Norway.

Environmental Monitoring and Modeling of Drilling Discharges at a Location with Vulnerable Seabed Fauna: Comparison between Field Measurements and Model Simulations

Offshore drilling activities were carried out by Statoil at the Hyme field, located in the Norwegian Sea, in an area with vulnerable seabed fauna. Cold water corals (Lophelia) were identified in vicinity of the drilling well location. Drilling activities in sensitive areas requires that the operator perform an assessment of potential impact or risk of drilling discharges prior to the drilling operation. The risk assessment is an input to the planning of the drilling operation with regards to minimize negative impacts on corals or other vulnerable fauna present. In addition, environmental monitoring during the drilling operation is undertaken in such areas, to document and, if possible, prevent potential impacts on the seabed fauna. The monitoring program at the Hyme field included measurements of ocean currents, temperature, salinity, turbidity and sedimentation of particles at the drilling location during the drilling operation. After drilling, the environmental risk assessment was updated with actual current data and high resolution discharge data for the whole discharge period. The results from the field measurements were used for validation of model simulations of dispersion and deposition of discharged drilling particles, in order to predict actual exposure and consequently potential effects or risk to the corals. In the present paper a comparison between model simulations and field measurements is presented. The model predicted particle exposure concentrations and burial of corals will be verified against turbidity measurements in the water column and particle sedimentation measurements at different distances from the discharge points. A high level accuracy in the model simulations, as basis for assessment of potential impacts to biota, is of high importance. This enables the operator to evaluate alternatives with regards to drilling discharge solutions (discharge point etc.) with lowest impact on environmental resources at the drilling site prior to drilling. A high level of accuracy is also important in the validation of the simulation.

Application of Quantitative Risk Assessment in Produced Water Management – the Environmental Impact Factor (EIF)

The Dose-related Risk and Effect Assessment Model (DREAM) was developed through a JIP in the period 1997–2000 and was implemented for produced water (PW) management in the Norwegian sector of the North Sea as a part of the ‘Zero discharge work’, 2000–2005. The initial version of DREAM included two approaches to PW management, the Environmental Impact Factor (EIF) and a body burden related risk assessment model focusing on selected PW compounds. The EIF, addressed in the present chapter, has found broad application in the North Sea and has also been used in other offshore production areas by different companies. The produced water EIF is based on the risk assessment principles described in the EU Technical Guidance Document (TGD), comparing the Predicted Environmental Concentration (PEC) and the Predicted No Effect Concentration (PNEC) of PW compounds. The quantitative risk element in the model is represented by the water volume where PEC exceeds PNEC, including the combined risk of all major PW constituents, both naturally occurring compounds and industry-added chemicals. The EIF is used as a management tool, primarily to identify and perform cost–benefit analyses of PW mitigation measures and best available technology (BAT). The method enables the operator to identify the compounds posing the most significant environmental risk in PW, and further to rank different PW discharges with respect to environmental significance and risk. This chapter describes the EIF method and focuses on examples of application of the tool on specific offshore production fields. A description of how the EIF fits into Statoil’s environmental management system is also given, including the link between risk assessment, selection of BAT and field validation through environmental monitoring.

LEFT – a web-based tool for the remote measurement and estimation of ecological value across global landscapes

Summary 1.The overall aim in the development of the Local Ecological Footprinting tool (LEFT) was to design a web-based tool that could provide quickly obtained quantitative data to assist landowners when making land-use change decisions and to help them minimise the environmental impact and determine areas of greatest ecological risk in their operations. 2.LEFT works for almost any region in the world and uses freely available satellite imagery, biotic and abiotic data from existing global databases, models and algorithms to deliver a customised report for a selected area within one hour of job submission. 3.Biotic data automatically obtained for a selected landscape includes terrestrial vertebrate and plant species occurrence data, information on their conservation status and remotely sensed vegetation productivity. Abiotic information obtained includes temperature, precipitation, water availability, insolation, topography, elevation, distribution of urban infrastructure, and location of wetlands. 4.The tool performs a number of analyses on the biotic and abiotic data to produce maps for the selected area at a 30m resolution depicting land cover type, numbers of globally threatened terrestrial vertebrate and plant species, beta-diversity of terrestrial vertebrates and plants, habitat intactness, wetland habitat connectivity, numbers of migratory species and vegetation resilience. Results are also aggregated to produce a summary map demonstrating areas of high and low ecological value across the selected area. 5.LEFT has been designed to be intuitive to use, requiring no specialised software or user expertise. Input is extremely easy and requires the user to highlight the area of interest on a map or using grid co-ordinates. Output is delivered via the web application and comprises a customised PDF containing the maps and a zip file of GIS data for the area requested. Users may run an unlimited number of LEFT analyses and download reports free of charge. In addition to the free tool described in this paper, there is also a paid service: individual LEFT analyses can be upgraded for a charge to allow access to the geographically subsetted datasets generated for each report. This data is supplied as a zip file containing raster datasets for the layers in the LEFT analysis in GeoTIFF format. These can be opened and queried in a Geographical Information System (GIS) software package. This article is protected by copyright. All rights reserved.