1Materials and Chemistry

Fate and effects of dispersed oil Examples from research projects 2001-2008

Effects of Dispersed Oil WorkshopAnchorage, March 2008

Alf G. MelbyeResearch Manager

Fate and Effects – Marine Environmental Chemistry

SINTEF Materials and Chemistry

2Materials and Chemistry

Outline of presentation

Identification of knowledge gaps Overview of recent research on fate and effects of

dispersed oil on cod larvae and Calanus finmarchicus at SINTEF

Recommendation for further research

3Materials and Chemistry

Identification of knowledge gaps

Earlier experimental work adopted methodology from Concawe for preparation of dispersed oil in ecotox-studies For acute oil spill situations, the size distribution in earlier

experiments was not realistic or controlled The assignment of water soluble and particle-bound oil

compounds was not clear An regional risk assessment of

oil and gas production in northern Norway (“ULB 2003”) identified dispersed oil as a significant environmental risk in the water column

4Materials and Chemistry

Overview of recent research on fate and effects of dispersed oil

Controlled generation of oil dispersions

Realistic, reproducible and documented size distributions

10 ml/min

Peristaltic pump channel 10 ml/min

FMI piston pump

Generation of dispersion

100 % 50 % 25 % 12.5 % 6.75 %

20 ml/min 160ml/min

Waste

DISPERSION EXPOSURE

Input 10 ml/min sea water per channel

CONTROL

100 % 50 % 25 % 12.5 % 6.75 %

WSF EXPOSURE CONTROL

Filter

5Materials and Chemistry

Overview of recent research on fate and effects of dispersed oilControlled generation of oil dispersions cont.Decalins as indicators of oil droplets

0

1

2

3

4

D1 D2 D3 D4 D5 V1 V2 V3 V4 V5

Exposure group

Co

nce

ntr

atio

n (

µg

/L)

Decalin

C1-decalins

C2-decalins

C3-decalins

C4-decalins

Visualisation of oil droplets

6Materials and Chemistry

Controlled generation of oil dispersions

Size distribution of droplets Troll 200+

res idue at different loadings (50 and 100%)

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60

Size (µm )

Co

nce

ntr

atio

n

(µl/

l)

Size distribution of droplets Skarv 200+

residue at different loadings (50 and 100%)

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60

Size (µm )C

on

cen

trat

ion

µl/

L

7Materials and Chemistry

Changing energy input – changed size distribution:

Size distribution during settling in stagnant

w ater (20 m m w ater colum n); Troll 200+ residue

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60

Size (µm )

Co

nce

ntr

atio

n µ

l/L

0 min

30 min

60 min

Size dis tribution of Troll 200+ res idue at

different energy inputs

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60

Size (µm )

Co

nce

trat

ion

(µl

/L)

100%

75%

The effect of settling – changed size distribution and concentration:

8Materials and Chemistry

Overview of recent research on fate and effects of dispersed oil

Exposure of cod larvae – uptake and distribution

ControlNo bile

WSFMetabolites in bileDependant on

concentration

DispersionMetabolites in bileDependant on

concentration

9Materials and Chemistry

Overview of recent research on fate and effects of dispersed oil

Exposure of cod larvae – effects on growth

Experiment 1

Day 18

Start N.a.N. 1 2 3 4 5 Control

µg

DW

larv

a-1

20

40

60

80

100

120

140

160

V D

Day 5

Experiment 2

Day 15

Start N.a.N. 1 2 3 4 5 Control

µg

DW

larv

a-1

20

40

60

80

100

120

140

160

V D

Day 5

Experiment 3

Day 12

Start N.a.N. 1 2 3 4 5 Control

µg

DW

larv

a-1

20

40

60

80

100

120

140

160

V D

Day 5

Exposure to dispersed oil affects growth of cod larvae

10Materials and Chemistry

Overview of recent research on fate and effects of dispersed oil

Exposure of Calanus finmarchicus – uptake and distribution

Low concentration:

The copepod is able to feed; uptake via food

High concentration:

Oil droplets are attached to the body and mouth; the copepod is unable to feed

11Materials and Chemistry

The toxicity of oil dispersions

Main objective: Determine the relative contribution og particulate and dissolved oil to toxicity

Results are to be used in estimating the toxic impact of oil in water dispersions based on on oil concentration, oil composition oil droplet size distribution

12Materials and Chemistry

The toxicity of oil dispersions cont.

Methodology Generate dispersions of known concentration (composition) and

droplet size distribution Determine the toxicity of the dispersions Calculate the concentration of dissolved components (from

dissolution theory) Calculate the toxicity of the dissolved phase by the unit toxicity

model Determine the contribution of dispersed oil from the difference

between the total mixture toxicity and the toxicity of the dissolved phase

13Materials and Chemistry

Suggestion for further research

Continue ecotox-testing on relevant organisms under realistic conditions

Create and validate data and knowledge on fate of dispersed oil for incorporation in numerical models; Droplet formation Coalescence Adsorption characteristics – particles in the water column and

sediment Surface properties as function of time (“skin formation”) Biodegradation – persistent compounds?

14Materials and Chemistry

This work has been carried out by:

• Trond Nordtug, Bjørn Henrik Hansen, Alf G. Melbye, Øistein Johansen and Kjell Inge Reitan– SINTEF

• Sonnich Meier, Anders Mangor-Jensen and Bjørn Einar Grøsvik – Institute of Marine Research

• Anders Olsen – NTNU

• Dag Altin – Biotrix

The work has been funded by StatoilHydro, National Research Council of Norway and OLF

THANK YOU FOR YOUR ATTENTION!