GULFTENE C16-18 ISOMERISED OLEFINS - NICNAS

loading of the test substance relative to the weight of sediment in each test vessel. This result
indicates that the test substance exhibits some toxicity to this species of sediment dwelling
organism. Furthermore, it should be noted that the levels of chemical in the piles of drill
cuttings may be up to 100 000 mg/kg which is well in excess of 1 250 mg/kg. Consequently,
the piles of drill cuttings may be toxic to this species.
Alga Growth Inhibition Test (Environment & Resource Technology Ltd 1995)
The tests on the effect of C16-18 alpha olefins, isomerised to the marine alga Skeletonema
costatum was conducted in accordance with (US EPA 1985) using five WAFs of the test
substance prepared with nominal loadings of test substance of 560, 1 000, 1 800, 3 200 and 5
600 mg/L in nutrient enriched sea water, and a control. The tests were conducted in duplicate
over a 72 hour period at a temperature of 20°C and pH between 8.39 and 9.01. After 72
hours, a 4% inhibition in biomass was observed for the media containing 3 200 mg/L WAF,
while 12% inhibition was observed for the media containing the highest WAF loading.
Accordingly the NOEL is 1 800 mg/L, the 72 hour EbL50 is greater than 5 600 mg/L, and the
test substance may be considered to be practically non toxic to this species up to the limit of
its water solubility.
The table above also contains entries for other tests on Acartia tonsa (marine copepod), and
Skeletenoma costatum (marine algae) performed on material known as “Olefin Isomers IV”.
These tests were performed by the Norwegian Institute for Water Research, and summary
reports only were provided. While the test samples were isomerised olefins intended for use
in drilling muds, there is no information on the relevant molecular weight range. However,
the results listed are in general accord with those of the better detailed reports, and are
included in the table for completion. Similarly, a test report on the toxicity of a Syn-Teq
drilling mud containing isomerised olefins to the sediment reworker Corophium volutator
was also submitted with the application (Orkney Water Test Centre 1994). Again the exact
nature of the olefin components of the mud were not specified, but the results are in general
agreement with those of the other test on this species, and need not be discussed further.
Indigenous Species
Toxicity testing on three representative species indigenous to the Western Australian marine
environment has also been performed, and fairly detailed summary reports also included in
the application. The results of these tests are given in the table below.
Toxicity Tests on Western Australian Marine Species (Tsvetnenko YB Evans LH Gorrie J )
Test Species Results (WAF - Nominal)
Acute Toxicity to Marine
Invertebrate
Acute Toxicity to Marine
Copepod
Penaeus monodon
(Tiger prawn)
Gladioferens imparipes
(copepod)
LL50 (96 h)>21.7 g/L
NOEL (96 h) = 11.2 g/L
LL50 (48 h) >224.2 g/L
NOEL (48 h) 242.4 g/L
FULL PUBLIC REPORT 26 April 2000
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