example of the equipment and related procedures required for a field effectiveness test is the
Australian National Plan Oil Spill Dispersant Effectiveness Field Test Kit (Nat-DET) Operational Guide,
available at:
http://www.amsa.gov.au/forms-and-publications/Publications/NatDET_Guide_2012.pdf
.
SMART protocol
The SMART (Special Monitoring of Applied Response Technologies) protocol was developed by
the U.S. Coast Guard (USCG) and others. SMART has three tiers (note that these are not related
to the response tiers used in contingency planning):
l
Tier I: visual monitoring.
l
Tier II: combines visual monitoring with on-water teams conducting real-time water column
monitoring (using a fluorometer) at a single depth with water sample collection for later analysis.
l
Tier III: expands on the Tier II water monitoring to meet the information needs of the incident.
This may include monitoring at multiple depths (using the fluorometer) and also taking water
quality measurements or more extensive water samples.
The initial motivation behind the development of
the SMART programme was to provide the spill
incident Command with technically valid
information on dispersant application. This
protocol was to be used for guidance only to
confirm that dispersant application was working.
The SMART protocol seeks to strike a balance
between the operational imperatives in quickly
obtaining data while still following sound scientific
principles. The SMART Protocol does not attempt
to produce an oil mass balance but rather infers
and provides an indication of the relative
effectiveness of the dispersant.
IPIECA-IOGP Oil Spill Response Joint Industry Project
10
Successful dispersion of
weathered oils is possible
under some
circumstances. The
picture shows Alaskan
North Slope crude oil
being dispersed during a
sea trial after 55 hours
weathering and a viscosity
of 15,000–20,000 cP; the
dispersed oil cloud can be
clearly seen.
Tier I: visual monitoring
Tier 1 recommends the use of either trained or experienced persons to observe the development
of a light-brown coloured cloud or plume of oil, which is used as an indicator to determine that
the dispersant is working. These visual observations can then be augmented by remote sensing
technology, such as IR detectors, if available. The methodology and training for such visual
observers has been well developed in the addenda to the SMART documentation. In some
circumstances it can take tens of minutes for the dispersion to occur, and observers should take
this into account if rapid dispersion is not observed.
Sour
ce: Dr T
im Lunel, ITOPF
It is important to note that false indications can be observed which
may lead to inaccurate conclusions about the effectiveness of the
dispersant. Oil ‘herding’, for example, occurs when the oil is not
treated by the dispersant but instead is displaced by the dispersant
application platform or dispersant spray; on a smaller scale, this
phenomenon is known as ‘lacing’. Herding and lacing give the
appearance that the dispersant was effective, even though little
dispersion has actually occurred. Conversely, during application, it
is also possible that the dispersed oil can be hidden under any
remaining surface oil, giving the impression that the dispersant was
not effective. If the dosage rate was too low, or the oil was not
particularly amenable to the application of dispersant, a visual
observation may lead to the conclusion that it was not effective. In this scenario, it would be more
accurate to conclude that a higher dose rate or second pass is required.
A milky white plume in the water will be present if the dispersant has missed the oil or has run off
extremely viscous or highly emulsified oil.
Visual monitoring requires good viewing conditions. Some weather conditions, such as fog and
haze, will make it difficult to carry out any observations of slick behaviour, including in particular
efforts to identify a cloud of dispersed oil.
Tier II: on-water monitoring
The Tier II protocol was developed to provide more reliable data, and involves the detection and
sampling of the underwater cloud or plume using either water column sampling for subsequent
testing, or in-water monitoring using fluorometry. Either sampling method will produce a single line
data set at the depth at which the sampling occurs. It is recommended that this depth is 1 metre
but in rougher weather conditions it may be more suitable to deploy at a depth of 2 metres.
Sampling and fluorometry readings should be taken where:
i.
no oil is present on the sea surface (background);
ii.
oil is present on the sea surface (natural dispersion); and
iii. oil has recently been sprayed with dispersant (chemically dispersed).
A transect should be followed through the slick when taking the fluorometry readings, as
illustrated in Figure 3 on page 12. The protocol suggests a rule of thumb, i.e. that if there is an
increase in readings of five times between the untreated oil (left) and the dispersed oil (right), the
dispersant may be considered to be effective.
The use of Tier II (and Tier III) monitoring is most readily carried out when dispersant is applied
from vessels. Although airborne application of dispersant can be extremely effective, post-spill
monitoring following an aerial spray operation can be challenging. To accurately deploy a
monitoring vessel into a zone that has been sprayed from the air needs well-practised teams that
routinely perform exercises in conjunction with spray aircraft. Although post-spill monitoring may
11
At-sea monitoring of surface dispersant effectiveness
Natuna Sea, Singapore,
2000: a white plume
indicates that the
dispersant is not effective
on this highly viscous oil.
Sour
ce: Dr T
im Lunel, ITOPF