For
several days last week the mainstream media ran vivid reports on Guillemots and
Razorbills coming ashore in Dorset and Devon with their feathers gummed up by a
“mystery” substance. There were speculative statements that it could be Palm
Oil, so with the wonders of internet search engines this led to a marked jump in
hits on an earlier Natur Cymru blog about Palm Oil lumps being mistaken for ambergris.
More useful however might have been checking out websites that deal with the
transportation of the range of vegetable oils.
Some
interesting experimental releases of such oils were done in France to plan for
accidents. Palm Oil itself has a pour point (the temperature at which it melts)
well above our winter sea temperatures. In the experimental releases it was
observed to form a scatter of small lumps, so it was a rather unlikely cause of
the problem. Several of the other vegetable oils have lower pour points, but
they have been found to polymerise in seawater as decay sets in, rather than forming
the sticky mousse emulsions that crude oils frequently do.
After
a vessel carrying Sunflower Oil capsized off Anglesey the fresh oil spread as a
very thin slick. When reaching the shore it gave rocks the appearance of having
a thin coat of varnish. Being non-toxic it did not cause limpets to drop off
and it soon vanished. More surprising to those of us then new to vegetable oil
spills, it sometimes formed elastic sheets at the edge of some high shore rock
pools and turned into thousands of little lumps like pieces of discarded
chewing gum. As it went rancid an aroma of less salubrious chip shops hung over
a few beaches.
A
problem in the recent South Coast incident was that in the absence of a ship
reporting damage to its tanks, or perhaps to a tank on a container ship, no one
seemed to know what the mystery substance was for several days. This had
consequences both for tracing the likely source and for anyone attempting to
treat wildlife casualties. Seen from a distance just through media reports, the
process of getting even preliminary scientific analyses to type the substance seemed
to be rather slow. This delay just added extra hype to the “mystery” and the report
that it was a refined mineral oil still seems rather non-specific.
There
are lessons in this incident for authorities in Wales, particularly for those
responsible after 1st April when Natural Resources Wales (NRW) goes
live. It is to be hoped that NRW will have adequate capability to get analyses
of strange substances affecting wildlife done promptly without having to
prevail upon the goodwill of distant laboratories in England.
In
practice samples need to be collected and processed for two rather different
purposes. The first one, to find out what it might be, needs to be done quickly
and can be based on whatever can be got to a suitable lab. However duplicate or
triplicate samples may also need to be taken that have to be much more
carefully stored and properly sealed as forensic specimens. There are already established
protocols for handling oil samples in case of subsequent legal proceedings.
To
end, here is a cautionary tale. Many years ago at sea we happened to pass a
mile or two from an oil drilling platform where well testing was taking place.
This involved flaring off the flow of oil. From a distance with binoculars, in
addition to clouds of black smoke billowing up from the flare, “rain” was
visible dropping from the flame. Later that day and at a distance down tide of
the platform we came across a mass of small black and slightly crisp oil pellets
on the sea surface. A sample was picked up and, in due course via HM
Coastguard, was sent for analysis. The lab reported that it had the
characteristics of heavy fuel oil. This delighted the PR side of the oil
company, though the operational people did admit that there had been incomplete
combustion and modifications were made to the flare. The fractions of the oil
burnt as it was sprayed through a flare would have been similar to the fractions
taken off during refining.
This
article was written by Ivor Rees
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