Applied Chemistry

No. 2 - 2001

Contact Person:

Alf G. MelbyePhone: +47 73 59 13 85E-mail: alf.g.melbye@chem.sintef.no

Bioavailibility and effects of dispersed oil on marine zooplankton

SINTEF Applied Chemistry has studied effects of dispersed oil on the copepod Calanus fi nmarchicus - the most abun-dant zooplankton species in the Norwe-gian sector. The organisms actively fi l-trate seawater for food particles (phyto-plankton) up to 50 µm. The project has been fi nanced by the Norwegian oil and gas industry association.

A major objective for the oil companies and the Norwegian Pollution Control Authorities (SFT) is to develop predictive models for the fate and behaviour of sea-water discharges from offshore activities. These models include transport, acute toxic effects, uptake and biodegradation, and accumulation in the food chain.

Knowledge regarding the fate and effects of dispersed oil in the marine environ-ment has been lacking. This project has focused on acute toxic effects, bio-uptake / adsorption and biodegradation of dis-persed oil. A challenge has been to design a system for generating dispersed oil in the size range 1-10 µm, refl ecting dispersed oil in a typical produced water. A number of different methods for gen-erating droplets have been tested, and the most successful method was using an ultrasonication probe in an oil:water mixture. The oil used in the experiments was a de-aromatised base oil.

The recently developed droplet generator was used to produce exposure solutions in acute toxic tests and bioaccumulation studies with the zooplankton C. fi nmarchicus. The results from the acute toxic tests have been compared with results from tests exposing the zoo-plankton with a water-soluble fraction of the oil used. The results show that dis-persed oil has a measurable acute toxic effect for the chosen test-organism. Fur-ther, the test organisms show both an intake of oil and external fouling by oil particles.

Laboratory studies for determination of degradation rates of dispersed oil require a study period considerably longer than mean suspension times typical for lab-oratory scale tests. (Droplets tend to coalesce or adhere to container walls.). The experiment was designed to omit problems related to droplet stability, and a system using an immobilised oil fi lm on an inert carrier (tefl on sheet) was designed. The thickness of the immo-bilised oil fi lm was adjusted to approxi-mately 10 µm, refl ecting typical average diameter of dispersed oil droplets. The results show that hydrocarbons in the oil phase degrade at a slower rate, com-pared to hydrocarbons in solution.

Two images demonstrating epifl uorescence of C. fi nmarchicus after exposure of dispersed oil spiked with chlorophyll. Images in the right half are seen under blue light and images in the left half are the same image showing fl uorescense from chlorofyll only.

Environmental Engineering

Association (NSF, by Mr. Rolf Duus) has the secretariat and Per S. Daling of SINTEF is convenor for the working group.

At the 1st CEN- meeting of the CEN/BT/Task Force 120 Oil Spill Identifi -cation” held in Helsinki on November 2000, delegates from 10 European countries agreed to work out three pro-tocols / guidelines based on the revised Nordtest Methodology, that cover the following issues:

• Issue 1: Guidelines on the method-ology for identifi cation of waterborne oils.

• Issue 2: Guidelines for sampling of waterborne oils for oil spill identifi ca-tion

• Issue 3: Analytical methodology and guidance to data processing, interpre-tation and reporting in oil spill identifi -cation.

12 laboratories involved in on-going Round Robin testing

As a part of the harmonization, a Round Robin test based on the revised Nor-dtest oil spill identifi cation methodology is taking place this year, where 12 lab-oratories from UK, France, The Neth-erlands, Germany, Norway, Sweden, Denmark and Finland are participating.

The results and experiences from this RR-test will be presented and dis-cussed at the next meeting of the CEN/BT/Task Force 120 Oil Spill Identifi ca-tion” in Hamburg in September 27th - 28th.

Improved and standardized methodology for Oil Spill Identifi cation

Harmonize the revised methodol-ogy into a European standard for oil spill identifi cation.

Parallel and in addition to this ongoing Nordtest project, the Technical Board (BT) of the European Committee for Standardization (CEN) in May last year established a Task Force (working group) called: “CEN/BT/Task Force 120 Oil Spill Identifi cation” for harmonizing a European standard for oil spill iden-tifi cation. The Norwegian Standards

Revision of the NORDTEST Methodology for Oil Spill Identifi -cation

Nordtest (http://www.vtt.fi /nordtest/) is an institution under the Nordic Council of Ministers, and acts as a joint Nordic body in the fi eld of conformity assess-ment. In April 2000, Nordtest initiated a project called “Revision of the Nordtest Methodology for Oil Spill Identifi cation”. This ongoing project is a co-operation between the National Oil Spill Identifi -cation laboratories in Norway Sweden, Finland, Denmark and Battelle Labo-ratories in USA. Senior Scientist Per Daling at SINTEF is the leader of this projectgroup. The existing Nordtest Methodology for Oil Spill Identifi cation has over the past 10 years formed an important “platform” for solving oil spill identifi -cation cases both in Scandinavia and in countries like the US, Canada, the Netherlands, the UK and Ireland. There is, however, now a need for further improvements of the methodology, both on analytical procedures and in use of data processing techniques that have become available in recent years. The main objectives of this NORDTEST project are therefore to refi ne the exist-ing Nordtest methodology into a techni-cally more robust and legally defensible oil spill identifi cation methodology. The approach is to make more systematic use of “diagnostic ratios” between natu-ral, ubiquitous and stable compounds that occur in crude oils and most petro-leum products.

Small variations between the abundance of naturally occurring compounds (expressed as “Diagnostic ratios”) between crude oils produced in the same oil fi eld can be strong legally defensible diagnostic indicies in oil spill identifi cation cases.

Strong “national feelings” at the last NORDTEST project meeting in Roskilde in Denmark

Contact persons:

SINTEF: Per S. Daling / Liv-Guri FaksnessPer.Daling@chem.sintef.no /Liv-Guri.Faksness@chem.sintef.no

CEN / NSF: Rolf DuusRolf.Duus@nas.no

Rolf Duus, NAS, Norway, Asger B. Hansen, DMU, Denmark, Per S. Daling, SINTEF, Niina Viitala, Finland, Nina Gjøs, SINTEF, Gerhard Dahlmann, BSH, Germany (specially invited), Liv-Guri Faksness, SINTEF, Jørgen Avnskjold, DMU, Denmark, Jonas Johansson, SKL, Sweden, Mads P. Schreiber, Nordtest, Finland.Scott Stout, Battelle, USA (not present)

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Environmental Engineering

Students and teachers in the UNIS course “Fate and modelling of pollutants in the Arctic”, prior to the 70 km snow-scooter excursion from Longyearbyen to Svea. (Darth Vader on the far left.)

University Students on Svalbard Learn to Use OSCAR 2000 The University Courses on Svalbard (UNIS) is a university institution in Longyearbyen, latitude 77° N. UNIS is owned by the four Norwegian Uni-versities on the mainland, and offers high level university courses within the four disciplines of Arctic Biology, Geol-ogy, Geophysics and Technology. (See www.unis.no for further details.)

Dr. Per Johan Brandvik, on leave from SINTEF Applied Chemistry, is responsi-ble for arranging several courses focus-ing on “Pollution in the Arctic”. One such course, “Fate and modelling of pollutants in the Arctic” is lectured intensively over 3 weeks and includes a one-week excursion with a research vessel in the marginal ice zone.

One week of this course is the theory behind and the use of modern mod-elling systems to model fate and behaviour of oil spills. The program system “OSCAR - Oil Spill Contingency and Response” from SINTEF Applied Chemistry is used for this purpose. (See http://www.sintef.no/units/chem/environment/number.htm for further information on the OSCAR model.) This

year Dr. Mark Reed, supported by May Kristin Ditlevsen, taught the modelling portion of the course, which included both theoretical background and practi-cal applications. Many of the students also chose to use OSCAR 2000 as part of their fi nal course project.

A 70 km excursion by snow-scooter across the mountains to Svea to visit

SINTEF Applied Chemistry’s fi eld sta-tion and to perform oil-in-ice experi-ments and demonstrations on the Van Mijen fjord concluded the course.

Fifth International Marine Environmental Modelling Seminar 2001

Hosted by

U.S. Minerals Management Service, Herndon, VirginiaSINTEF Applied Chemistry, Trondheim, Norway

New Orleans 9-11 October, 2001

You are cordially invited to par-ticipate in the year 2001 Interna-tional Marine Environmental Model-ling Seminar. The purpose of the conference is to provide a forum for

scientists and environmental man-agers to exchange information and viewpoints on environmental issues. Special emphasis is placed on recent developments in applications

tools for environmental assessment. International and inter-disciplinary applications for environmental man-agement support are of special interest.

For registration and information: http://www.sintef.no/units/chem/environment/sem2001/invitation.htme-mail: may.ditlevsen@chem.sintef.no, Tel. + 47-73-591364, Fax. + 47-73-597051

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Strømstad

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Applied Chemistry

Environmental Engineering Newsletter

Environmental EngineeringN-7465 Trondheim, Norway

Phone: + 47 73 59 28 73Fax: + 47 73 59 70 51

http://www.sintef.no/units/chem/environment

Layout: Tone Aas Heggenhougen

Applied Chemistry

Please return if the addressee is unknown, or has left your company

OSCAR 2000 Applied to Dispersant Use in Shallow Coastal Waters

Contact Person:

Mark ReedPhone: +47 73 59 12 32mark.reed@chem.sintef.no

Simulations of several hypothetical experimental oil spill scenarios were carried out to estimate mass bal-ances and hydrocarbon concentration fi elds following dispersant application in shallow waters. All scenarios were for relatively minor releases of 10 bar-rels or less, and included application of chemical dispersants to the slick shortly after release. Slick lifetimes were under 5 hours. Due to shallow depths (< 6 m), a small fraction of the released hydrocarbons was asso-ciated with bottom sediments after 24 hours.

A three-dimensional hydrodynamic model was used to supply realistic current fi elds for these simulations. The currents support previous obser-vations that the circulation in the study area is largely tidally driven. In the center of the study area, the circulation appears relatively weak. These simulations suggest that the eventual behavior of an oil droplet cloud in the middle of the study area will be relatively insensitive to release point or time in the tidal cycle.A limited analysis was run to evaluate model sensitivity to the oil-sediment sorption coeffi cient. Increasing this coeffi cient by a factor of 10 resulted in an approximately linear increase in

OSCAR2000 snapshot of the mid-depth hydrodynamic fi eld at maximum fl ood velocity through the shipping channel.

Concentration contours after 90 minutes, release from site 1, wind from the southeast. Maximum total hydrocarbon concentration is about 100 ppm near the water surface.

the fraction of oil in the sediments. Sensitivity of estimated time-to-zero-volume for the 0.1-ppm concentration contour demonstrated that the model prediction of 3.5 days was associated with an uncertainty of 12 hours for a release of 10 barrels. This time estimate is also a function of the oil-sediment interaction rate, since more oil in the sediments means less oil in the water column.