TÉCNICAS E INSTRUMENTOS DE RECOLECCIÓN DE DATOS

A comparison of weathered crude oil (SO) from plumage was made with and without the use of olive oil as a pre-conditioner, and the results of these experiments are presented in Fig. 6.24.

In this case, it can be seen that an improvement in removal becomes apparent at N = 7 and culminates in a maximum removal, at N = 12, of 96.4% and 94.5% with and without olive oil, respectively. These values are significantly different at the SE level. Although not as pronounced as with feather clusters, this once again demonstrates the advantage of the judicious use of pre-conditioner in cleansing of weathered oiled from plumage.

70 75 80 85 90 95 100 6 7 8 9 10 11 12 N C(%)

With olive oil Without olive oil

Figure 6.24: Comparison between the pick-up, C (%), of weathered crude oil from plumage as a function of the number of treatments, N, with and without the use of olive oil as a pre-conditioner. Error bars represent the SE for five replicates. The data are presented in Table 47 in Appendix 6.

6.4 Comparison of weathered crude oil removal between feather

clusters and plumage

Oil removal experiments that were conducted on penguin carcasses, using one-day weathering, were compared to results obtained for the removal of oil from feather clusters, under the same conditions. A comparative histogram of the results obtained for feather clusters and plumage is presented in Fig. 6.25.

It may be seen in Fig. 6.25 that, for all values of N, the removal of oil is higher for clusters than for plumage. Thus the initial pick-up from feather clusters is 56.7%, significantly higher than 27.8% from plumage. However, the difference becomes less pronounced as the number of treatments increases. In particular, a maximum removal of

97.6% is obtained for feather clusters (after 14 treatments), while the corresponding figure for plumage is 94.5% (after 12 treatments). This is consistent with results for the removal of fresh and tarry oils, which also shows higher removals for feather clusters than for plumage.

0 20 40 60 80 100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 N Oil removed (%)

Plumage Feather cluster

Figure 6.25: Comparison between the removal of weathered crude oil from feather clusters and plumage, using the optimal magnetic particles. Error bars represent the 95% confidence intervals for five replicates. The data are presented in Table 48 in Appendix 6.

6.5 Conclusions

Having been demonstrated to effectively remove fresh and tarry contaminants from feathers and plumage, the optimal iron powder grade was used to remove different weathered contaminants, Shell crude oil (SO) and bunker oil (BO2), from duck and penguin feather clusters and penguin plumage (carcasses).

An investigation into the effect of the time of weathering on the removal of contaminants from both duck and penguin feather clusters was carried out. It was found that for both crude oil and bunker oil, and for duck and penguin feathers, the removal of oil during the first several treatments (particularly the initial treatment) significantly decreases as the time of weathering increases. However, this variation becomes less pronounced as the number of treatments increases. Hence, for both of these contaminants, the maximum pick-up is comparable for all times of weathering, approaching ca. 100% for duck feathers and ca. 98% for penguin feathers. For both types of contaminant, it was also noted that the number of treatments needed to achieve maximum removal from both duck and penguin feathers is less for a shorter time of weathering, e.g. being N = 10 for one-day weathering compared to N = 14 for seven-day and fourteen-day weathering.

A comparison between duck and penguin feathers for the removal of weathered crude oil was carried out. It was found that, for all times of weathering, the removal for the first several treatments is significantly higher for duck feathers than for penguin feathers. The difference, however, becomes less pronounced as the number of treatments increases. Thus the maximum removals become more comparable, even though still significantly higher for duck feathers than for penguin feathers. A similar comparison between duck and penguin feathers was also carried out for weathered bunker oil. Contrary to the crude oil results it was found that, for all times of weathering, the removal of oil after the first several treatments is significantly higher for penguin feathers than for duck feathers. However, the difference, again, becomes less pronounced as the number of treatments increases; with the maximum removals being more comparable and the final removal being significantly higher for duck feathers. Thus there appears to be a complex inter- dependency between weathered oil removal and time of weathering and feather type.

A comparison between crude oil and bunker oil with respect to removal from duck feathers was carried out. It was found that, for one-day and seven-day times of weathering, the oil removal (during the first seven treatments) is generally higher for crude oil than for bunker oil. However, the opposite is found after both oils have been weathered for fourteen days reflecting, perhaps, significant changes in composition. However, the maximum removals achieved for these are essentially equivalent. A similar comparison between crude oil and bunker oil for the removal of oil from penguin feathers was carried out. It was found that, for all times of weathering, the oil removal is lower for crude oil than for bunker oil. Thus in addition to the dependency of removal on time of weathering and feather type, there is also a complex dependency on contamination.

An investigation into the candidacy of olive oil as a pre-conditioner in the magnetic removal of weathered oils from feathers was carried out. At first, experiments on the affinity of the optimal iron powder for olive oil itself were conducted. The results indicate that iron powder effectively removes olive oil, showing a removal of ca. 100% from both a glass substrate and duck feathers.

Different methods were trialled to explore the way in which olive oil can be most effectively applied as a pre-conditioner in the magnetic harvesting process, in relation to weathered contaminants. Preliminary testing suggested that the procedure most likely to give an optimum outcome involves the application of olive oil at N = 6 and then once more at N = 10, if required. More extensive experiments were then conducted for the magnetic removal of seven-day weathered crude oil from duck and penguin feathers employing olive oil as a pre-conditioner. It was found that the application of olive oil from N = 6 onwards results in a significant improvement in removal from both duck and penguin feathers. It is also worth noting that for duck feathers, when using olive oil, the maximum removal is achieved earlier at ten treatments compared to fourteen treatments when not using olive oil. Similar experiments were conducted for the removal of fourteen-day weathered bunker oil from duck and penguin feathers using olive oil as a pre-conditioner. It was found that the application of olive oil from N = 6 onwards also results in a significant improvement in weathered oil removal from both duck and penguin feathers, the improvement being more pronounced for the latter. Again, for both duck and penguin feathers, the use of olive oil leads to the maximum removal being

achieved earlier at ten treatments compared to twelve or fourteen treatments than when not using olive oil. It was also noted that for both contaminants and types of feathers the use of olive oil leads to the removal of discolouration. Therefore, it is demonstrated that the judicious use of pre-conditioner can offer real advantages.

As with feather clusters, experiments were carried out with respect to the magnetic removal of weathered crude oil from plumage (penguin carcasses) - with and without using olive oil. When olive oil is not used, the maximum removal from plumage is around 94.5%, although quite promising, still lower than 96.5% when using olive oil. This is consistent with what is achieved with feather clusters, i.e. an improved removal with the use of olive oil.

A comparison between feather clusters and plumage, with respect to the removal of one- day weathered crude oil, was also conducted. It was clear that the removal, especially the initial removal, is considerably higher for feather clusters than for plumage. This is consistent with the results obtained for fresh and tarry contaminants (Chapter 4 and Chapter 5), which show higher removal for feather clusters than for feather plumage. This is not surprising given that plumage is a less accessible matrix. The accessibility might be improved by the application of iron powder in a stream of compressed air.

6.6 References

Australian Maritime Safety Authority (AMSA) 2004, Weathering of oil at sea and the implications for the estimation of the window of opportunity for use of oil spill

dispersants, viewed 11 June 2004,

<http://www.amsa.gov.au/marine%5Fenvironment%5Fprotection/national%5Fplan/gen eral%5Finformation/dispersants%5Finformation/weathering%5Fof%5Foil%5Fat%5Fs ea.asp >.

Bassères, A, Verschuere, B, Jacques, JP, Holtzinger, G, Tramier, B 1994, ‘A new cleaning product for oiled birds: Laboratory and metabolic tests and initial results of field tests’, Spill Sci. Technol. Bull., vol. 1, no. 2, pp. 159–164.

Bryndza, HE, Foster, JP, McCartney, JH, Lundberg, B, Lober, JC 1991, ‘Surfactant efficacy in removal of petrochemicals from feathers’, Contribution No.4523 from the Central Research and Development Department and the Petrochemicals Department of the E.I. Du pont de Nemours &Co. Inc, Experimental Station, Wilmington, Delaware, 19880-0328 and Contribution No.8702 from Tri-Sate Bird Rescue and Research Inc., Box 1713, Wilmington, Delaware, 19899.

Bryndza, H 2005, Removing oil from feathers - Critical issues and misconceptions, viewed 25 May 2005, <http://www.ibrrc.org/pdfs/ibrrc_policy.pdf>.

Clark, RB, Evans, S, Palmer, N 1997, Review of the effectiveness of, and management procedures for, the rehabilitation (treatment, cleaning and release) of oiled birds with reference to the Sea Empress oil spill, Sea Empress Environment Evaluation Committee (SEEEC) contract Report 243.

Daling, SP & Strom, T 1999, ‘Weathering of oils at sea: Model/Field data comparisons’, Spill Sci. Techno. Bull., vol. 5, no. 1, pp. 63-74.

Dao, HV, Ngeh, LN, Bigger, SW, Orbell, JD, Healy, M, Jessop, R, Dann, P 2006, ‘Magnetic cleansing of weathered/tarry oiled feathers - the role of pre-conditioners’,

Frink, L & Crozer-Jones, B 1986, ‘Oiled bird rehabilitation: Fact and fallacy’, J.Wild. Rehabil., vol. 5, pp. 68-79.

Healy, M 2005, Personal communication, Phillip Island Nature Park, Melbourne, Australia.

Hill, JF 1999, Oil spills and Marine Wildlife: Guidelines for a response plan for the Isle of Mull, Project Report commissioned by the Hebridean Whale and Dolphin Trust.

Holcomb, J & Russell, M 1999, ‘New breakthroughs in oiled bird rehabilitation’, J. Wild. Rehabil., vol. 22, no. 4, pp. 6-8.

International Bird Rescue Research Centre (IBRRC) 2000, Report on the Treasure oil spill, viewed 10 May 2005, <http://www.ibrrc.org/treasure_report_3.html>.

International Tanker Owners Pollution Federation Limited (ITOPF-a) 2004, ITOPF Handbook 2004/2005, viewed 18 December 2004,

<http://www.itopf.com/itopfhandbook2004.pdf>.

International Tanker Owners Pollution Federation Limited (ITOPF-b) 2004, Fate of marine oil spills, viewed 19 December 2004 <http://www.itopf.com/fate.html>.

Leighton, AF 2003, Petroleum oils and wildlife, viewed 12 October 2003, <http://wildlife.usask.ca/bookhtml/oil/oil.htm>.

Mecoy, L 2005, California officials trade oil spill, The News and Observer, viewed 3 May 2005, <http://newsobserver.com/news/story/2048678p-8433818c.html>.

Michel, J & Hayes, OM 1999, ‘Weathering patterns of oil residues eight years after the Exxon Valdez Oil spill’, Mar. Poll. Bull., vol. 38, no. 10, pp. 855-863.

Moles, A, Holland, L, Short, J 2002, ‘Effectiveness in the laboratory of Corexit 9527 and 9500 in dispersing fresh, weathered, and emulsion of Alaska north slope crude oil under subarctic conditions’, Spill Sci. & Technol. Bull., vol. 7, no. 5-6, pp. 241-247.