Comparison of Substance-Based and Whole-Effluent Toxicity of Produced Water Discharges from Norwegian Offshore Oil and Gas Installations.

When assessing the environmental risks of offshore produced water discharges, it is key to properly assess the toxicity of this complex mixture. Toxicity can be assessed either through the application of whole-effluent toxicity (WET) testing or based on its substance-based chemical composition or both. In the present study, the toxicity assessed based on WET and substance-based was compared for 25 offshore produced water effluents collected for the Norwegian implementation of the Oslo-Paris convention risk-based assessment program.

Toward a harmonized approach for environmental assessment of human activities in the marine environment.

With a foreseen increase in maritime activities, and driven by new policies and conventions aiming at sustainable management of the marine ecosystem, spatial management at sea is of growing importance. Spatial management should ensure that the collective pressures caused by anthropogenic activities on the marine ecosystem are kept within acceptable levels. A multitude of approaches to environmental assessment are available to provide insight for sustainable management, and there is a need for a harmonized and integrated environmental assessment approach that can be used for different purposes and variable levels of detail.

Species sensitivity distributions for suspended clays, sediment burial, and grain size change in the marine environment.

Assessment of the environmental risk of discharges, containing both chemicals and suspended solids (e.g., drilling discharges to the marine environment), requires an evaluation of the effects of both toxic and nontoxic pollutants.

Assessment of environmental risks from toxic and nontoxic stressors; a proposed concept for a risk-based management tool for offshore drilling discharges.

In order to improve the ecological status of aquatic systems, both toxic (e.g., chemical) and nontoxic stressors (e.

Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water.

Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of the species from being affected, the present study aimed to apply these techniques to define treatment regimes of H2O2 and effectively eliminate as many species as possible.

Functional and structural impact of linuron on a freshwater community of primary producers: the use of immobilized algae.

An approach in determining ecosystem integrity and stress on ecosystem level is to assess processes within ecosystems. The aim of the present study was to evaluate the potential use of an in situ assay with immobilized Chlorella vulgaris as an indicator of effects on ecosystem functioning with regard to primary production. The herbicide linuron, applied in concentrations of 20, 60, and 180 microg linuron/L, was used to induce direct effects on primary producers.

Copper toxicity in relation to surface water-dissolved organic matter: biological effects to Daphnia magna.

Water quality standards for copper are usually stated in total element concentrations. It is known, however, that a major part of the copper can be bound in complexes that are biologically not available. Natural organic matter, such as humic and fulvic acids, are strong complexing agents that may affect the bioavailable copper (Cu2+) concentration.

Assessing structural and functional plankton responses to carbendazim toxicity.

A model ecosystem experiment was conducted to investigate the ability of an in situ Daphnia magna feeding bioassay to assess impairment of ecosystem function. Animals were deployed in model ecosystems dosed with different concentrations of the fungicide carbendazim, and effects on the postexposure feeding rate of D. magna were compared with effects on zooplankton species richness (ecosystem structure) and development of phytoplankton biomass (ecosystem function).