To main content

Dispersants have limited effects on exposure rates of oil spills on fish eggs and larvae in shelf seas

Dispersants have limited effects on exposure rates of oil spills on fish eggs and larvae in shelf seas

Category
Journal publication
Abstract
Early life stages of fish are particularly vulnerable to oil spills. Simulations of overlap of fish eggs and larvae with oil from different oil-spill scenarios, both without and with the dispersant Corexit 9500, enable quantitative comparisons of dispersants as a mitigation alternative. We have used model simulations of a blow out of 4500 m3 of crude oil per day (Statfjord light crude) for 30 days at three locations along the Norwegian coast. Eggs were released from nine different known spawning grounds, in the period from March 1st until the end of April, and all spawning products were followed for 90 days from the spill start at April first independent of time for spawning. We have modeled overlap between spawning products and oil concentrations giving a total polycyclic hydrocarbon (TPAH) concentration of more than 1.0 or 0.1 ppb (μg/l). At these orders of magnitude, we expect acute mortality or sublethal effects, respectively. In general, adding dispersants results in higher concentrations of TPAHs in a reduced volume of water compared to not adding dispersants. Also, the TPAHs are displaced deeper in the water column. Model simulations of the spill scenarios showed that addition of chemical dispersant in general moderately decreased the fraction of eggs and larvae that were exposed above the selected threshold values.
Language
English
Author(s)
  • Vikebø Frode Bendiksen
  • Rønningen Petter
  • Meier Sonnich
  • Grøsvik Bjørn Einar
  • Lien Vidar Surén
Affiliation
  • Institute of Marine Research
  • SINTEF Ocean / Miljø og nye ressurser
  • Institute of Marine Research
Year
2015
Published in
Environmental Science and Technology
ISSN
0013-936X
Publisher
ACS Publications
Volume
49
Booklet
10
Page(s)
6061 - 6069