Frequently the only response to an oil spill is to wait until the oil arrives on the coast and be prepared for cleanup of the affected coastal environments. Many of the methods of cleanup are efficient in the removal of oil from the environment, but they have a heavy impact on the biological community several times worse than the oil itself. Therefore, the form of cleanup is also a relevant factor upon considering the degree of impact of an oil spill.
Our initial thought should be that the oil has caused damage to the environment to a lesser or greater extent. We now have to clean up this oil causing the minimum possible damage. This can only be done by the close cooperation of oil spill response professionals and environmental agencies to arrive at the best solution to the problem.
It is the duty of the Planning Team to notify those in command of the strategy to be adopted. The selection of the methods to be used is a very important stage in the response planning cycle. To take the correct decision early can be very decisive during the later stages of cleanup. Therefore it is important that the right people are selected for the planning team.
They need to receive the propt information about the spill and the weather conditions, knowledge of the logistical information in reference to the availability of personnel, equipment and material.
All of these headings are part of a good contingency plan if there is one for the location.
Based on this information and local reconnaissance, the team will have the conditions to recommend to the Executive Command the most efficient strategy in order to minimise the impact to the environment and bring the response to a good conclusion, successfully and at an acceptable cost.
The response team needs to be able to justify their recommendations and clarify to the command any expected penalties, in the event other measures are taken.
We have to clean the shore doing the least amount of damage possible.
Knowing when high tide and low tide will be, as well as how high up the shore the water will come for safety reasons is important.
Also how low the water will go to allow the team to know when to stop cleaning thus reducing the damage to the sensitive life in the lower shore
Knowing when the tide will turn will enabling the clean-up team to work but also to retreat to a safe place and avoid being cut off or trapped with no exit point.
This is especially important in flat areas or muddy areas as the tide will rise faster than a man can run. Many people have drowned collecting shellfish in flat areas and have not been able to get to safety before the tide arrived.
Tide tables like the one left show the times and heights of the tide for every day of the year.
These can be found at chandlers or even as apps for smartphones.
If you cannot find one for the exact shore where you will be working, then looking at the nearest ports and adding or deducting minutes will get the answer.
Make sure you add a safety margin to the result until you know exactly when high or low tide will be.
Clean-up of coastlines
These days it is very difficult to see an oil spill event without various (SCAT) Shoreline Clean-up Assessment Technique teams doing surveys for future clean up or for info during and after the clean up for the Planning team
When a spill occurs there are usually far to few people to quickly take on this part of the response but it is important, as it will enevitably save time and life in the decision as to what should be done first and how. This helps, operations, planning, safety, logistics and finance.
POSOW is a project co-financed by the EU under the Civil Protection Financial instrument developed in cooperation with ISPRA, Cedre, Sea Alarm and CPMR and coordinated by REMPEC a regional Centre of the Barcelona Convention produced 4 free manuals designed for volunteers and all responders involved in onshore response who have little or no previous knowledge of shoreline geography and descriptions of shoreline oiling.
Click the logo to access the 4 manuals or go to Documents/POSOW on this site.
I have borrowed some of the designs and wording as it is good to see simple designs showing how things work.
The cornerstone activity of SCAT is the shoreline assessment survey and its fundamental objective is to collect and document data on oiled shoreline conditions in rapid, accurate and systematic fashion.
Shoreline assessment surveys are based on several fundamental principles. These include:
The need for a coordinated and systematic shoreline assessment programme will be triggered by an incident leading to marine or coastal oil pollution.
The SCAT process includes eight basic steps:
Field Equipment Check list
Surveyors should also have appropriate clothing and personal protective equipment
for the conditions, for example:
Refreshments should be carried in remote locations
Survey steps and comments
Gain segment overview
Try to gain an overall perspective of the segment to be surveyed, either by viewing from an elevated position or, for shorter segments, walking its length.
Acquire a good perspective of the extent of shoreline oiling.
It is recommended to walk along the whole segment making general notes, returning to oiled areas that require more detailed documentation.
On longer segments it may be more efficient to carry outdetailed note-taking as the team progresses along the shore.
Photographs and video are very useful tools in documenting the shore’s appearance. Ensure accurate notes of photograph or video locations are made. Use the reference numbers of images from the digital camera used. GPS can be used to identify photo locations if available and necessary.
Don't take to many, this is a case when quality is better than quantity. Think what the photo is for? does it show the inclination of the shore for example.
photographs should be taken to:
Do not forget to indicate the location of the view point on your sketch.
Draw sketch/annotate map
A sketch is a very important part of the assessment. The sketch complements photographs and is required to document oiling conditions on the form. The location of all key features should be marked.
Complete assessment form
The completed Oiled Shoreline Assessment Form provides all the detailed information on the oiling conditions.
The team reviews the assessments to reach an agreement on major points. At a minimum, there must be a consensus on the oil character and distribution.
Check that forms and sketch maps are complete. Ensure that all photographs and videos have been accurately logged.
Prevent secondary pollution by cleaning any oiled footwear prior to departure.
Check that all equipment, survey gear, personal items and, litter is taken when leaving the site.
The essential first step of a ground survey is to divide the coastline into planning and operational work units called ‘segments’.
Within a given segment, the shoreline character will be relatively homogeneous (uniform) in terms of physical features and sediment type.
Boundaries between segments are established on the basis of prominent geological features such as a headland or presence of a river, changes in shoreline or substrate type, sometimes a change in oiling conditions, or establishment of the boundary of an operational area. Segment lengths are typically 200 - 2,000 m. If there are long stretches of uniform coast, segments may be established on the basis of operational features, such as access points, or simply by equal distances along the shore.
How to define segmentation
To assist in defining segments one can use:
Segmentation will be used throughout the response process. These segments are the basis for the development of treatment plans. Ultimately, each segment of shoreline will be considered individually in both planning and operational stages.
Each segment should be given a unique identification code. There are no rules to how this is done but simple systems are effective e.g. a code for each municipality followed by sequential numbers for each segment within that municipality.
Survey team members
The number of persons in a survey team and the number of teams required will depend on the circumstances of the incident.
Generally a survey team comprises:
In practice, during the reactive phase, team members can be volunteers drawn from a wide variety of organisations. Typical candidates for shoreline survey teams, targeted by this manual:
Know the coast intimately before people begin to start work on the clean-up
Photos below to cover these above in the note.
The presence of sub-surface oiling can be due to:
This sub-surface can only be evaluated by digging pits or trench. Such investigations should only be undertaken if buried oil is suspected.
Constructive and distructive beaches
Many beaches are constructive and distructive. Constructive is when the waves have a strong swash which is the rush of seawater up the beach after the breaking of a wave and weak backwash a low wave in proportion to length are created in calm weather and are less powerful break on the shore and deposit materials.
Destructive waves have a weak swash but a strong backwash are created in storm conditions high wave in proportion to length it breaks downwards with great force tend to erode the coast occur when the wave energy is high and the wave has traveled over a long fetch.
This problem that arises especially on coarse grained sandy beaches. During these periods oil can become buried in layers as in the photo right. It is always advisable to dig a hole to see if this has happened. Obviously to remove all the oil could generate huge quantities of waste so close coordination will be required.
Level refers to the height of oil on the shore in relation to the tide. This information is important to evaluate the risk of oil remobilisation.
Length refers to the along-shore distance (parallel to the water’s edge) of the oiled lines.
Width refers to the average across shore distance (perpendicular to the water’s edge) of the oil band within a segment or zone.Distribution represents the actual percentage of the surface that is covered by oil within a given area.
Percentage of coverage
Is probably the most difficult to estimate: the objective is not to provide an exact measurement of oil distribution, which is generally not homogenous, but to try to reach an average.
Level refers to the height of oil on the shore in relation to the tide.
This information is important to evaluate the risk of oil remobilisation.
TR Trace < 1%
SP Sporadic 1 - 10 %
PA Patchy 11 - 50 %
BR Broken 51 - 90 %
CO Continuous > 90 %
Refers to the average or dominant oil thickness within the segment or zone.
TO Thick oil (fresh oil or mousse > 1 cm thick)
CV Cover (oil or mousse from >0.1 cm to <1 cm on any surface)
CT Coat (visible oil <0.1 cm, which can be scraped off with fingernail)
FL Film (transparent or iridescent sheen or oily film)
This column provides a qualitative description of the form of oil.
FR Fresh oil (un-weathered, liquid oil)
MS Mousse (emulsified oil occurring over broad areas)
TB Tar balls (discrete accumulations of oil <10 cm in diameter)
TP Tar patties (discrete lumps or patches >10 cm diameter)
PA Patches (accumulation of oil > 1 m < 30 m)
SR Surface oil residue (non-cohesive, oiled surface sediments)
AP Asphalt pavements (cohesive, heavily oiled surface sediments)
TA Weathered tarry oil, almost solid consistency
Approximate overall exposure rating of the upper shore (or oiling) parts of the segment:
Sites which face into prevailing winds and recieve oceanic swell without and offshore breaks (Islands) for hundreds of kilometers.
Sites where strong onshore winds are frequent but also have a degree of shelter because of extensive shallow areas or other seaward obstructions.
Sites with a restricted sea area over which the wind blows (Fetch) generally <10km. They can face prevailing winds but with extensive shallow areas to seaward or may face away from prevailing winds.
Sites with a very restricted sea area over which blows (Fetch) genrally <2km and which face away from prevailing winds or have obstructions such as reefs to seaward or are fully enclosed:
Characteristics of sediment and beach slopes depend on exposure.
Photo right shows a very exposed boulder beach (note the slope and rounded boulders as good indicators of high exposure).
In ecology, as a rule, the more balanced and stable (sheltered) the environment, the greater the diversity of the species.
In accordance with the size of the grains, the percolation of oil will vary. Basically, it will be greater when the grains of sediments are larger. Thus, fine-grained beaches are less vulnerable to spills, since the greater compaction of the beach prevents the penetration of the oil. Beaches with coarse sand, on the other hand, are highly vulnerable in this sense, where the oil can penetrate many centimeters.
There are so many combinations with the amount of shoreline sediment types and size along with various types of oil and oiling.
There are various scales for classifying sediments based on the grain sizes. For the purposes of shoreline assessment, broad categories have been used. Use the box above as a guide to the size of sediment to determine the nature of the beach substrate. Categories have been chosen based on their implications for shoreline cleanup techniques. Well-known visual references (tennis ball, pencil diameter) can help to determine the size of sediment grains
Below are some photos of some 12 types of oiling taken for a volunteer manual for people carrying out shoreline impact studies
1 Thick oil (TO) Cedre 2 Cover (CV) OTRA 3 Coat (CT) ITOPF 4 Film (FL) ITOPF
5 Film (FL) Transparent sheen Cedre 6. Fresh (FR) liquid OTRA 7. Mousse (MS) ITOPF 8. Tar Balls (TB) Cedre
9. Tar Patties (PT) ITOPF 10. Patches (PA) Cedre 11. Surface Oil Residue (SR) OTRA 12. Asphalt Pavement (AP) OTRA
General comments / sketch / Taking photographs
The second part of the Assessment Form is for general comments. It is used to highlight particular points of interest or anomalies in the segment. This may include comments relating to:
The field sketch is an important component of the shoreline assessment process for
two principal reasons:
It is necessary to mention at least:
The surveyor should have gained an overview of the segment as their first task.
Drawing the sketch may come before or after the completion of the Assessment Form and taking photographs – this is largely a matter of preference and circumstances.
However, if it is done early in the survey, care should be taken to ensure key information such as photograph locations and any dug pits are annotated on the sketch before leaving the site. Note that if there are two or more members in the survey team, the various activities can be carried out simultaneously.
Determine the dimensions of the segment. Place the length and width of the intertidal zone as well as some of the more conspicuous features, such as groins or seawall segments. Using a pencil, indicate these measurements on the field sheet. Orient the longest dimension along the longest axis of the paper. Add a scale (use metric units) and a north arrow.
Lightly sketch in the outline of the intertidal zone or habitat being surveyed.
Show in final form (i.e. heavy pencil marks) the oiled zones, using a hatched pattern.
These zones should be the most conspicuous feature on the sketch, as shown below.
A letter is allocated to each oiled zone on the sketch that corresponds to the ‘Zone ID’
Use the checklist to indicate:
Photographs are very useful tools in documenting the shore’s appearance. However, some discipline is needed and care should be taken not to take too many photographs, which is very easy to do with digital cameras. Enough photographs should be taken to:
identify access routes or other operational features and on-going activities.
Do not forget to indicate the location of the view point on your sketch.
Most photographic management applications (e.g. Google Picasa, freely available) enable simple tagging of photograph sets and storage by date. If photographs can be uploaded at the end of the survey or at least on the same day, this will aid their cataloguing and secure storage. It also frees memory within a camera for future photographs.
Accurate indication of photograph locations should be made on the segment sketch.
As a rule of thumb, if you have taken more than 20-30 photographs at a site, then you have probably taken an too many.
With the experience of many responses over the years on different shorelines, varios tables have been put together showing what works well, medium and not at all; Colour code key Green works well, Orange works but not as good as green and red is not recomended but may work in some circumstances.
These formations have taken millennia to construct usually with high wave action.
This is a very dangerous place to put human beings to work during certain months.
When there is wave action the reflective wave in many cases will keep a slick some meters for impacting the cliffs, they also tend to be wet due to the wave so if there is contact with oil it does not tend to stick to the rock.
Great care from a safety point of view needs to be taken, information such as weather forecasts, tidal variations, etc. need to be known before these areas are approached.
This is one place where the supervision has to be done above the team of workers so that an overall view can be gained. There is a real danger of people being stranded with a rising tide.
Supervisors that are with the group usually make the same mistakes as the group because of the lack of overall vision.
Note: Cleaning vertical cliffs will be a dangerous operation confined to periods of calm weather and seas. Further complications arise in areas of substancial tidal movements. Two or more boats should work in tandem or, if single boats are deployed, under shore supervision. Due to the nature of the area experienced rock climbers have been used as this was the safest way to operate.
Consult local ecologists about whether clean-up is necessary at all, and what the disadvantages of a leave alone action would be.
If clean-up is necessary:
What to do:
What not to do:
The rocky coastlines vary greatly in relation to their economic, recreational and educational value and their role in the marine ecosystem. The rocky coastlines include a broad variety of habitats and different communities, significantly in relation to their sensitivity and capacity for recovery in relation to spills of hydrocarbons.
In general terms, the less sensitive coastlines the greater potential for natural recovery such as areas exposed to waves. The sheltered areas are much more sensitive to oil and also to the damage that could be caused by some cleanup techniques.
Due to its potential variability, sensitivity and the high cost of cleanup, it is essential that the contingency plans be sufficiently adaptable to the structure of the response options and adapted to the special peculiarities of each coastline. Sensitivity maps, details of access to the coast lines and directives on how the cleanups will be performed such as good communications between environmental assessors and those responsible for the cleanup.
The greater problems of oil spills on rocky coastlines are caused when the oil penetrates deeply into cracks and holes made by burrowing organisms. In circumstances where residual oil could pose a threat to colonies of marine mammals, birds or where other techniques could cause greater damage or disturbances, it could be appropriate to use a natural absorbent, such as peat, for the removal of this oil to avoid it penetrating into these locations and affecting the organisms that live in the location.
For cleanup along rocky coastlines, low-pressure, ambient temperature sea water may be used to clean up the oily residues. Final cleanup normally requires high pressure and will depend on how the oil is adhering to the rock. If the residual oil is adhering strongly to the rock or a very high degree of cleanup is required, it may be necessary to resort to hot water at high pressure.
Such “aggressive techniques” will cause irreversible damage to the natural flora and fauna that is found on the rocky coastline and therefore these techniques should be only used as a last resort. In many cases, it would be more appropriate to allow the less aggressive natural processes to act, e.g. wave action. In many cases these aggressive techniques are used where there is a lager tourist presence, remote sites can be left to mother nature to clean with assessments of the natural process.
These areas are difficult to clean and may release oil even after a thorough and time consuming clean-up operation.
What to do:
What not to do:
These areas are treated very similarly to rocky shores, techniques include flushing with high volume low pressure water to release oil trapped between or under the boulders. Rags, absorbent pads and de-greasing agents are used to clean the area, absorbent booms and pom-poms help contain the oil and stop it returning to the sea or re-oiling clean areas.
What to do:
What not to do:
These areas produce problems from a penetration point of view dependent on the type of oil and the inclination of the shoreline depends on how far the oil will penetrate.
During large oil spills with the correct mixture of environmentalists and response personnel new techniques can be developed for cleaning areas as this is a great opportunity to test new idea’s which cannot be done anywhere else.
During the Sea Empress incident we dug pits and sank skips into the shore lined them with thick plastic sheets washed the cobbles with de-greasing agents and water before replacing them where they came from on the shoreline.
The contaminated cobbles were in other areas were moved to the surf zone over a period of 4 days for the sea and the fine sands to clean. 5 days later there was no significant contamination. This is known as clay-oil flocculation and allows the oil to be dispersed naturally.
Concrete mixer lorries were used to wash the cobbles with water and in some cases de-greasing agents the released oil is skimmed off and the cobbles replaced. The good thing about this approach is the availability of these vehicles.
What to do:
What not to do:
In-situ Pit Washing of Oiled Cobbles
Pit washing was used for the first time during the Sea Empress incident to clean cobbles.
Large pits were dug to hold between 50 and 100 tonnes of material and lined with a heavy duty plastic liner. Cobbles were added and washed under high pressure water and an approved degreaser (surface cleaner).
Oil could then be skimmed off the surface of the pit and the cleaned cobbles returned to the beach.
Right In some cases sunken skips were used as the pit. It should be noted that this method of cleaning cobbles removes only the bulk oil. The remaining stained cobbles were not returned to the surface of the cobble zone but were buried to prevent re-oiling.
The same problem of penetration exists as with cobbles. Surf cleaning, pit washing and concrete lorries can be used to great effect, though it was found that removing the fine material before washing reduced the cleaning time as they tend to retain the oil.
There is as with all shoreline clean up a need to stop before more damage than necessary is caused and nature is allowed to take over. In sheltered areas bio-remediation has been tried by burying nutrients in the shoreline or spraying gelled versions, this is not a fast process but enhances the natural cleaning process.
Do's and Dont's as Cobbles above.
Shingle Washing Operations
During the Sea Empress incident in Wales, UK 1996 this innovative clean-up technique prove very useful.
Washing stations were set up at several locations. These were established from readily available equipment such as cement mixes, skips, temporary tanks, conveyors and scaffolding.
Oiled material is fed into a lorry-mounted cement mixer and seawater with an approved degreaser, and occasionally diesel, added. (However, later operations used neither degreaser or diesel as it was found that these were not necessary.) Operating the cement mixer agitates the material and loosens the oil.
The mixture is then left to separate. The oily water is then run-off into watertight skips or tanks and the oil removed by surface skimmers. The cleaned shingle was then returned to the beach. Treatment rates would depend on the degree of oiling, the capacity of the cement mixer and the number of cement mixers used. Cement mixers have a nominal capacity of 10 tonnes and, with a treatment cycle of 2 hours, some 50 tonnes per day can be treated. However, more recent work suggests that treatment cycles of this length may not always be necessary.
On shores with coarse grained sand the water brings the oil up the beach then the water sinks into the sand on its return to the sea. This action leaves the oil stranded in thin lines.Unless great care is taken huge amounts of sand will be removed with very little oil. This work is done with shovels or in some cases sorbent boom is stung out and rolls up the beach with the waves and picks up the oil on the outside of the boom.
Normally, oil can be removed from beaches of fine compacted sand without much difficulty, using a combination of well organised teams of workers. In the event it is necessary to use mechanical equipment to scrape off this contaminated sediment or to transport recovered residues, it should be done preferably by experienced people.
Care should be taken not to remove excessive quantities of sand, thus generating a large quantity of residues.
Care should also be taken not to mix the oil deeply in the substrate. Manual collection of oil is preferable to mechanical removal. Final cleanup operations may include manual removal of tar balls or larger fragments of oil pancakes.
What to do:
What not to do:
Amenity beaches with installations
Dependent on the type of sand, tourist beaches may have hundreds of thousands of foot prints on them as left here on Copacabana beach, Brasil, each one could be filled with oil right so there is a serious need for supervision of cleanup personnel to reduce the amount of sand removed with the oil.This becomes a time consuming job and many people will be picking up 3 or 4 times as much sand as oil while the supervisors back is turned. photo AP
What to do:
What not to do:
Many of the techniques used on other shoreline will do more damage to this environment than is necessary. The physical removal of oil may do great damage to the sensitive substrates. The use of chemicals may cause the penetration of the oil into the substrates damaging plant and animal life.
The amount of invertibrate life held in this type of shore is enormous, with oil on the surface the weight of your feet push the oil down into this anaerobic substrate where without oxygen will be a source of toxicity for many years causing problems for any life that encounters it.
These areas tend to be flat and extensive; there load bearing capacity is very low so vehicles should not be used. Many of these areas have killed people who got stuck in the mud and could not get out before the rising tide arrived.
These areas are highly sensitive and very dangerous so safety is a high priority if it is deemed necessary to do something. Normally they are left alone to allow natural cleaning to take place.
What to do:
What not to do:
What to do:
What not to do:
A cleanup may be performed with small groups of people who work in the mangrove swamps, directed by professionals in the environmental area. Absorbent materials should be used, preferably of natural origin, or blankets and booms as long as they are not left permanently in the affected area. For the removal of excess oil, light skimmers with portable pumps can be used.
If it is deamed necessary to use heavy equipment a lot of damage will be caused by the wheels or track of these vehicles as seen in the bottm left photo. The use of material such as trackway as in the photo top right spreads the load causing much less impact.
The destructions of areas within this habitat bottom right photo allows space and time for foreign invasive plants to take over thus upsetting the fragile balance in the area. In some countries when that growth dies back in the autumn, controlled burning is used which burns the oil and plant foliage but the roots in the water logged sediment will allow the plant to sprout in the spring. This has be shown to remove over 90% of the oil and little or no damage to the saltmarsh.
Although these areas may have little amenity use, theycould be one of the more sensitive ecological areas and during certain months sustain large migratory bird populations
What to do:
What not to do:
Spill damage, containment and clean-up operations may be very different in estuarine areas compared with other coastlines. In particular water in oil emulsions may sink on entering less saline waters. It may also be necessary to take into consideration a multitude of commercial and economical factors, in addition to ecological and amenity aspects. Large bodies of water flowing through small mouths cause very strong currents
What to do:
What not to do:
Small islands and deltas
What to do:
What not to do:
Spill damage will be mainly economical rather than ecological.
What not to do:
I am not completely against the green organisations though they do tend to uses some people who are lacking in the grey matter department.
The photo right shows a Greenpeace rubber boat dripping oil. This was taken during the Haven incident near Genoa, Italy.
Greenpeace decided to go boating in the oil then came back to a clean marina contaminating the boats but disappearing to let someone else clean up their mess (thank you).
Fisheries and aquaculture
If fishfarms, oyster beds or harvestable fields of alcae are affected the first priority should is to avoid further contamination. Cleaning operations can usually be more effectively organised by the operators of such ventures. Sorbents and other materials should be made available if required.
What to do:
What not to do:
I put this black and white photo here to show the amount of fishing boats that were working in the 1960's. This is the port of Great Yarmouth on the East coast of England.
I worked out of this port during the 1970's as it serviced the Southern North Sea. At that time the fishing boats had gone to make way for the oil and gas boom. The river was full of supply vessels.
I suppose with all those fishing boats working there is no wonder the fish stocks have disappeared.
Just as well, imagine the amount of compensation that would have need to be paid for all those fishing boats in the case of a spill.
The direct damage will be economical. Dispersion of smaller spills may be an established routine.
What to do:
What not to do:
The degree of sensitivity in these areas normally depends on who live there. In the top right photo is the white house belonging to a very wealty and influencial person so of course the sensitivity is very high.
Harbour walls, slipways, jetties and steps are normally cleaned with high pressure water and some use of de-greasing chemicals the oily water is caught with absorbents to avoid re-contaminating clean areas.
Close supervision is required as high pressure water can cut human tissue causing complication during hospitilisation. It can also cut in this case the sandstone wall which can then be erroded further by the sea.
In areas of rip rap as seen in the photo left, large quantities of oil can be held withing the spaces between the blocks which may take months to clean.
From a purely ecological perspective, the major preoccupation would be the effects of the hydrocarbons in the sediments in relation to the sheltered areas. This is due to the fact that these sediments are more productive and will probably retain more hydrocarbons, since they support the life of a great variety of marine worms, molluscs and crustaceans. These animals could die if the oil penetrates into the sediments, as was the case with the spill of the Sea Empress 1996, when many amphipods, crustaceans and molluscs died due to the highly toxic oil sweeping across mud flats.
The recovery from the contamination by hydrocarbons depends on the sensitivity of the species affected. After the spill of the Sea Empress, for example the populations of molluscs that lived in the mud recovered over a period of just a few months, however the populations of amphipods only returned to normal after a year. After a spill of hydrocarbons it is possible that the opportunists, such as some of the species of worms, show a spectacular growth over a short period of time.
The contamination by hydrocarbons is also related to the persistence of the hydrocarbons in the sediments. After the spill of the
The reduction over the long term of fauna in the sediment can have an adverse effect on the birds and fish that use the marine areas for feeding and, in some countries, the persistence of oil on sandy beaches could affect the reproduction of turtles. Some cases have been registered of the deaths of seal pups and, in some cases, adult seals do not succeed in reproducing in zones contaminated by oil.
The material, which for some reason or another was not removed and remains in the sediment, may block the light of a considerable portion of the surface of the marshes and, consequently reduce their productivity. Besides this, it consists of a potential source of contamination and a risk for the animals of this ecosystem.
The type of community affected often has to be taken into consideration, since many organisms possess the capacity to clean themselves, besides frequently living under natural conditions of stress and succeed well in resisting an oil spill. On the other hand, there are endemic species of organisms that may be seriously affected by an oil spill, with irreversible damage being caused to the community.
The local biological composition may also be presented as an important agent in the behavior of the oil in the sediment. Muddy beaches with fine-grained sand, principally, to display organisms adapted to living in galleries and tubes, which are physical means for the passage of oil and its consequent penetration to the lower layers of the sediment.
And now with all the relevant information:
Shoreline type, size, degree of exposure, angle, socio-economical issues, environmental issues, access, etc.
We need supervision at a rate of 1 to 10 maybe 15 this depends on whether they clean-up team are reliable.
Along with 3 other guys I had the charge of 250 women on a Mozambique beach during their civil war. The impacted beach was fairly flat made from fine packed sand it was about 3 kms in length with a small mangrove at one end and about 5000 tonnes of heavy crude oil.
It was impossible to know at any one time how many of the women were working.
Luckily they were very honest people and in all stages of pregnancy, the young girls set up a creche. When baby cried a girl would fetch mum, she would feed the baby and go back to work.
The were paid $1 and a bowl of rice per day. It was over to quickly, this job had a lasting impression on me.
I was in charge of a shoreline in Southern Ireland. There was a cliff at the back which reduced access to foot.
The shore was very rocky not allowing access from the water. The most expensive helicopter in the country was hired as it belonged to the prime minister's son. We got a cheaper one as fast as we could from Scotland.
All oil was removed in 1 tonne bags under slung the helicopter. I had people filling these bags with clean rocks of clean sea weed because the money was good and they did not want it to finish.
We even had a couple of guys dressed in oiley Tyvec suits rob a house up the cliff and leave their oily foot prints as a good reason for the police to look at the shoreline operation. They also stole a shotgun which at the time was a life sentence.
Hiring people is easy but releasing them can be very difficult. It all depends on where you are as to how the job needs to be supervised.
Techniques for coastal cleanup
The cleanup has the objective of minimising the adverse environmental impacts of an oil spill, making possible the restoration of the ecological functions of the environment and allowing human use of the coast.
The choice of cleanup techniques may be determined by the quantity and type of hydrocarbon, the ecological and socio-economic importance of the affected zones and the physical characteristics, such as wave energy.
For the choice of the technique to be applied in a coastal cleanup, several factors should be taken into account, such as difficulty of access, cost of the operation, type of oil and, principally, the type of environment affected. Each oil spill is unique; therefore, there are no general rules, standards or evaluation by means of criteria to be adopted.
Generally the most viable technique is a combination of very judicious manual recovery methods, such as the use of natural absorbents and pumping with natural cleaning.
Principal directives of clean-up procedure
The first rule for the cleanup of a coastal area is to check if most of the floating oil has already arrived at the coast. We cannot execute the cleanup of the coastal areas with the oil still arriving in these areas, because the impacts on the cleanup and efforts on the local communities will be greater.
The wetter zone of sand at the limit with the water of the sea is the region where the greatest numbers of organisms live. This is the most sensitive location in biological levels. In this region, then, the transit of people should be avoided and, principally, that of heavy vehicles, besides crushing the organisms present, it can cause greater penetration of oil in the sediments.
The hydrocarbon present in the location should be carried to the upper zone of the inter-tidal region by the action of the waves and tides themselves. Booms can be positioned at angles to decrease the amount of spread along the shoreline concentrating the oil in one place.
The vegetation present in the upper band of the beach (supra littoral) generally is damaged due to the transit of a large number of people and cleanup equipment. We should give special attention to these areas.
One should take maximum care in the removal of the least amount of uncontaminated sediments, besides the surviving animals and plants. Manual removal, with shovels and rakes, for example, is adequate for small areas contaminated with hydrocarbons in places where it has not penetrated deeply.
It is a useful technique to clean up patches of oil, in the cases where the use of heavy equipment is limited by access, when the machines could damage the structure of the beach.
The manual recovery of petroleum should be done just on the upper band of the beach (middle littoral upper and supra littoral). This procedure should be performed very carefully, removing the minimum amount of sand possible. In order to do this, wooden scrapers, rakes, shovels, buckets, skimmers (and not spades and hoes). Normally, several days of cleanup is necessary, since with each high tide, more oil in carried up.
The marine algae contaminated in low energy areas, can sometimes be removed. In higher energy areas where the algae is continually wet the mucus membrane on the fronds tend reject oil this should not be touched as the more life left on a shoreline the faster it will recover.
The photograph on the right shows contaminated seaweed removed and awaiting final disposal during the Sea Empress clean up in Wales, UK 1996.
Now here is an alarming story that surfaced in France:
A stretch of beach near Lannion in
The seaweed Ulva lactuca more commonly known as sea lettuce is growing abnormally fast in the region due to heavy nitrate pollution caused by intensive farming practices. The nitrates leach out of the soil and wash down in to the sea through local rivers. Wave action then washes the seaweed on to the beach in large amounts up to a metre deep in so called 'green tides' where it starts to decompose, during the decomposition process highly toxic hydrogen sulphide gas is formed. Because of its the gooey nature a thick crust forms on the top of the rotting seaweed causing the gas to accumulate and become trapped inside the rotting mounds. When the crust is broken by stepping on it the trapped gas is released.
Local mayor René Ropartz took the decision to close the beach at Trédrez-Locquémeau when a rider lost consciousness and his horse was killed after riding across the rotting sea weed last week. A council worker is also being treated in a hospital at Lannion after collapsing and falling in to a coma while clearing the deadly weed.
Earlier this year several dogs were killed after walking over the rotting seaweed, dogs and small children are particularly susceptible to the gas as they are lower to the ground and more likely to inhale larger amounts. The problem is not isolated to the beach at Trédrez, other beaches along the western coast of
All of the oil recovered removed from the beach should be, preferably in sealed drums or bags. Once the majority of the oil has been removed, the uses of natural absorbents such as peat, straw, etc or synthetic, are very efficient for the final cleanup of the beach. These should be spread on the fringe of the infra littoral area (region closest to the water), always at low tide. With rise of the tide, the product acts for several hours and along the entire length of the inter-tidal zone. At high tide, the product should be removed manually, respecting in the same way the lower bands of the beach.
In locations with great quantities of trash, such as in ports or close to mangrove swamps, normally the manual removal of this trash is done using nets, in order to facilitate the removal of oil by means of another process. If this can be done before the oil arrives this greatly reduces the amount of waste to be disposed of.
This is a brief description of Hydrogen Sulphide (H2S) it is colourless. Its odour is commonly referred to as the smell of rotten eggs. It has a vapour density 1.189 (Air=1.0) it is heavier than air. It is highly explosive. Its auto ignition temp is 260 degrees C. It is water solubility 2.9 percent (2.9g/100 ml water at 20 degrees C. It is also extremely corrosive, destroying steel and rubber seals very quickly.
Effects of H2S Note: Smell is only a temporary warning. Do not rely on your nose.
10,000 parts per million = 1 percent. 1 ppm: Can be smelled
10 ppm: Occupational Exposure Limit, for 8 hours: At very low concentrations of less than 10-100 ppm,
15 ppm: Occupational Exposure Limit, allowable for 15 minutes of exposure.
20 ppm: Occupational Exposure Limit, at this level workers must wear appropriate breathing apparatus.
100 ppm: the gas kills the sense of smell in 3-15 minutes and will cause you to cough or your eyes to water, possible headache, nausea, throat irritation.
200 ppm: your eyes and throat will begin to burn and you will get Headaches. Sense of smell lost rapidly.
300 ppm: Immediately Dangerous to Life and Health level. Positive pressure breathing apparatus required.
500 ppm: Loss of reasoning and balance with respiratory disturbances in 2 to 15 minutes.
700 ppm: Immediate unconsciousness. Death will result if not rescued ASAP.
1000 ppm: Immediate unconsciousness. Causes seizures, loss of control of bowel and bladder, breathing will stop and death will result if not rescued promptly. Immediate resuscitation needed.
Comparison of H2S with other lethal gasses will help you to understand the importance why:
(a) you can not work alone
(b) the reason for prompt and swift action. H2S has a threshold limit of 20 ppm and a lethal concentration of 600 ppm.
Hydrogen cyanide (used in Nazi gas chambers) has a threshold limit of 10 ppm and a lethal concentration of 300 ppm.
Carbon monoxide (CO) has a threshold limit of 50 ppm and a lethal concentration of 1,000 ppm.
You should have got the picture by now that when having to work with this substance an understanding of why so much preparation and precautions needs to be taken.
The saturation of the ground with low pressure water (<10 psi) permits that part of the oil floats for later retrieval. The water flushing applied to rocky shorelines could have an impact depending on the pressure used. Jetting at high pressures remove all of the biological community, aggravating even more the biological impact on the affected environment.
Low pressure water flushing with large volumes of sea water could be beneficial, if used with caution. This can be efficient in the removal of substantial quantities of oil from the vegetation where the vegetation is relatively stable and continuous.
Washing with running water of the affected rocky coastlines is a recommended technique as long as it does not provoke more damage. However, this technique should be utilized immediately after the areas were affected. Otherwise, it will prove inefficient in the removal of weathered oil that has already adhered to the substrate.
A perforated hose is placed in the location of contamination with the objective of saturating the sediment with water so that the oil floats. Any oil liberated should be recovered immediately so that contamination of other areas does not occur.
This water is pumped at and low pressure. In porous sediments, the flows of water in the substrate, by the difference in densities, will easily carry the loose oil to the surface. The viscosity of the oil will influence the success of the operation. We should always use water with the same physical-chemical characteristics as the place of the spill to reduce further damage.
High pressure jet washing is particularly adequate for firm sediments will low slope and rocky areas. The use of low pressure water at ambient temperature minimizes the damage to the structure of the sediments and to the organisms. Unless it is really necessary, the use of high pressure jet washing is not recommended.
As might be expected, high pressure jet cleaning could cause erosion, modifications of the substrate, physical harm to the plants and make the oil penetrate even more deeply into the sediments.
Right is what was called the omni boom, basically it is so high a pressure a hydraulic arm has to be employed.
It is suggested that studies be made of the effect of this method on marshes and mangrove swamps before its application.
High pressure is used to remove oil that has adhered to the hard substrate or to artificial structures.
We should take care that the oil does not flow into sensitive habitats. It should be recovered to prevent later contamination of adjacent areas. This technique should not be used directly on fixed algae or in inter-tidal areas.
Left shows black oil floating on the surface but the fine light coloured sediments have been driven into the most sensitive zone on this shoreline thus doing more damage than the oil did when it arrived.
Environmental effects: all of the fixed animal and plants in the zone of direct spray will be removed, even when it is used correctly. It can cause deeper contamination of the substrate or uncontaminated sediments. This technique is not viable for mud or clay sediments.
The habitat may be physically disturbed by traffic during the operations and these environments may be suffocated by the fine sediments washed over sensitive areas. If retention methods are not effective, the oil could contaminate sediments in the adjacent areas. Inundation can cause loss of sediment and erosion of the coastal contours and scrub vegetation. Fine sediment can bury benthic organisms especially in the upper tidal zone.
Hot water can kill animals and plants. Generally, marine organisms live adapted to a range of temperature, salinity and oxygenation. If the containment of the area is not sufficient, this water used in jet washing may contaminate other areas.
Jet cleaning may cause erosion in other areas, causing great damage to the vegetation of areas of mangrove swamps.
During the Exxon Valdez spill, the use of high-pressure hot water was applied as a cleanup technique and resulted in a greater impact and longer periods of recovery for the coastal organisms.
The sea temperatures ranges from 0º – 3º C so the use of hot water make the shore look clean but effectivly kills everything. The principal cause of these impacts was the massive elimination of species with long life cycles that required many years to re-establish themselves. This technique came about more from media pressure to remove thin layers of oil coating stones than common sense.
The natural cleaning in this area during the following winter would have done the job with far less environmental impact as was shown during the following spring in areas that had not been touched the previous year.
These techniques do not always result in an improvement in the recovery of the environment; fortunately we usually learn from our mistakes but public and media pressure can be great and things are done to that should never be done but, by then it is to late.
Steam cleanup is generally made with very hot waters, with temperatures between 77°C and 100°C.
This method is very destructive and should only be applied in locations where no biological communities exist because the effects of this technique are devastating, being capable of causing the complete death of an entire biological community and the rate of recovery is cancelled by other factors.
In the event that small areas of the coast will be used to eliminate the oil slicks on solid substrate or on man made structures, this technique should be used during high tides, so that the contaminated water may be contained and removed.
From a safety point of view: More than 11,000 workers helped clean up the
During steam cleaning operations masks should be used to avoid breathing in vapourised oil which then stays in the lungs and becomes a heath problem for responder for many years after the event. This is a real problem for many workers who worked there.
Workers were sent out to clean oil without proper training or protective equipment. While media and public attention focused on the thousands of oiled and dead seabirds, otters, and other wildlife, little attention was given to the harm done to the cleanup workers.
Person Protective Equipment (PPE) for 11,000 people for months of work in a remote region can be a logistical nightmare.
The utilisation of absorbent materials for the removal of oil normally is done manually. The absorbents may be defined as materials with the capacity to recover oil by means of absorption and/or adsorption. There are three basic types of absorbents.
Natural organic materials, such as cork, hay, fennel, sugar cane, coconut husks, peat
Mineral materials such as vermiculite, perlite and volcanic ash; Synthetic organic absorbents, such as polyurethane foam and polypropylene fibers.
The synthetic absorbents normally show a greater capacity for the retention of oil and may be obtained in a variety of forms, including booms, pads, and sheets. They normally have retention of 20 times oil to 1 times the weight of the absorbent thus the weight of the boom for recovery could be 20 times heavier.
Some absorbents may be treated with oleophilic agents, or by controlled heating, that results in an improvement in the capacity of the material, preferring oil to water.
In general the use of absorbents is only appropriate during the final stages of the cleanup in coastal environments are to aid in the removal of fine films of oil and that trapped in holes on rocks which are difficult to remove with other methods.
All synthetic absorbents must be recovered whereas natural ones can be left as long as they are not oil contaminated. It is important that synthetic granual absorbents are only used where they can be easily recovered on windy days this can be difficult.
Booms and pads are simple to use and keep control of, so if it is possible stay away from these granual types, they are usually yellow or white and when the wind catches them they blow all over the place and become time consuming and waste generators which you can do without.
The efficiency of the absorbent will depend on the type of the material used in its composition and the apertures of the mesh of the absorbent. Weathered oils and heavy fuel oil the more it adheres rather than absorbing. When you cut the boom open you find the outside black but the inside still clean. Even though they do not absorb heavy oils they can be very useful to keep the oil from spreading.
Thin strips of polypropylene are tied together in balls are used for the recovery of heavy or emulsified oils; they are excellent for oil caught in holes. Used separately if they escape can get into skimmers causing pumps to stop. They are also manufactured attached to ropes which are used in shorelines in inter tidal areas much the same as absorbents.
The greatest impacts on species are in reference to the possibility of ingestion and suffocation because of these materials, principally the granulated absorbents. Generally, synthetic absorbents take more time or do not degrade in the environment.
There are times normally in small ports or harbours where small quantities of diesel are spilled from for example a small fishing boat where absorbent boom or pads could be the only response.
In some countries absorbent booms are used as the first response to all spills and kilometers are used, raising the cost of the cleanup dramatically. Skimmers would have produced oil/water residues which are much easier to dispose of, we now have tonnes of dirty absorbent boom which cost a fortune to purchase and now will now cost a fortune to dispose of.
Insurance companies pay for reasonable expenditure.
This is an absorbent invented by an excentric englishman called Ken Frogbrook and made from straw in a plastic net it was made in a huge machine on site if there was straw available. It came in long lengths about 30 meter. The problem was it became a seriously heavy object to remove without it splitting and spilling its contents everywhere.
In this case we used it to for an access path to reduce the damage done by people walking across this water logged area. It worked very well for this type of job.
This product got the backing of people like Actress Joanna Lumbley who wanted to save the world at the time. The path right was on Shetland during the spill from MV Braer.
Shortly after she wanted to send the machine to Northern Russia for the Komi spill unfortunately there is no straw available in either location.
The cutting of plants covered with oil to the less than 3cm level of the sediment is a cleanup technique that results in direct physical destruction of the plant fibers. This severely reduces the quantity of photosynthetic tissue, except for the marshes during the time that the aerial portion of the plants dies to sprout again. At the time of the cut, the plant is more exposed to the toxic substances of the oil, favouring its contamination and reducing its immunity. The cutting of the base of the plant favours the penetration of the oil into the substrate, besides the death of the plant itself. Areas where the plants were removed or trampled are susceptible to erosion.
The use of this resource should have the approval of the environmental organisation. This technique has the objective of increasing the efficiency of the removal of the oil from contaminated substrates.
The degreaser has a role that is very similar to that of the dispersant. Some degreasers are slightly toxic, but the problem is that they make the oil biologically available in the environment.
The intention of this technique is to reduce pressure and temperature of the water at the time of cleaning. Some agents will disperse the oil away from the beach. The degreaser ruptures the molecular structure of the hydrocarbon.
When the product does not disperse the oil in the column of water, the liberated oil should be recovered on the surface of the water. The use of this material should be restricted in the proximity of areas of high productivity with the presence.
The toxicity and the effects of the dispersal of the treated oil vary widely among the products. The selection of a product should take into consideration its toxicity. Many of these products have certificates of biodegradability and their toxicological effects on organisms.
In many past cases, dispersants used along shorelines were common and have caused additional damage besides the oil and in some cases, has increase the penetration of the oil into the sediments or contaminate intact areas in the inter-tidal zone.
There is evidence that dispersed oil has varying degrees of toxicity for plants. According to the mixture, type of oil and dispersant, the problem of the application of dispersants occurs because often there is the bio-availability of the oil at the time of application.
Chemicals can be important in small cleanups and littoral fringes in combination with low-pressure flushing but in general their use is not recommended. Chemical alone are not efficient with emulsified oils or very viscous oils.
The need exists to perform experiments to test the toxicity and the efficiency of the different chemicals available for the various types of oil that are transported along our coasts.
There are many chemical degreasers on the market made from oranges and lemons they smell nice but in many cases large quantities have to be used to get better results than water under pressure.
The gelling agents transform the oil from the liquid state to a solid state. Polymers are applied at a rate of 10 to 45%, solidifying the oil in minutes.
Unfortunately they work considerably better in the laboratory than at the spill site.
In confined places the use of this material impedes the entrance of the oil into cracks in the rocks, sediments and impedes its propagation. It is possible that the oil does not completely solidify, unless the product is well mixed with the oil. Generally it is not used with very viscous oils.
These products are insoluble and have very low toxicity in the aquatic media. The oil that solidifies and is not recovered could have a longer impact because of the slower rates of weathering. Physical disturbance of the habitat is very probable during application and recovery.
If the product is well applied there could be a reduction in the volume of water recovered during the operation and the solidified residues could be transported more easily. Some countries accept disposal in sanitary landfills.
The mechanical removal is a method generally employed on sandy coasts, on which the contamination is extensive however, penetration is not very deep. Normally, patrols are used to remove the surface layer of contaminated oil; this layer should never be thicker than the penetration of the oil.
Another consideration we should make is in reference to the constructive cycles of the beach. If at the moment of the spill, a constructive period is underway, burial of contaminated sediments could take place, this technique may be considered.
Heavy vehicles can cause compaction of the sediment, causing the death of countless organisms due to crushing. The traffic of vehicles should be done preferentially on the driest part of the sand (Supra littoral).
Bear in mind that in past incidents mountains of waste have been generated using heavy machinery, anything up to 30 times more beach material than oil. Now imagine an impacted shoreline with 50,000m3 of oil, this has now become 1.5 million m3
Beach cleaning machines
These machines come in various sizes and can be very effective for the removal of tarballs especially on long stretches of beach. The system works with revolving or agetating steel screens with differing hole diameters, when the sand and tarballs are picked up the clean sand is returned by gravity to the beach and the tarballs and any other rubbish are held inside. When full it is towed to an area where it is emptied and seperated before final disposal.
Now lets look at the response to the Deepwater Horizon spill instead of using the machines as seen above which collect the tar balls sift the sand replacing it where it was, here we remove the sand with a few tarballs then have to wash it and maybe replace it in the same place. Intensive washing of sand removes any life (yes it is clean but it is also dead) and may suffocate life on the shoreline which it covers and will take longer to recover.
Sometimes we have the opportunity to transport the sediment to a surf zone of the beach, so that with the rise of the tide, together with force of the breaking waves, a natural washing of the sediments takes place. This technique is more appropriate for sand with a larger grain size or gravel that was lightly contaminated.
This technique also results in greater aeration of the sediment, besides mixing the sediment with the subsurface. This movement of sediment is generally done with tractors and causes the compactation of the sediment, besides the possibility of burying some organisms. This movement of contaminated sediments can result in oil films on the water. This reworking can expose some organisms and prevent their adherence.
Divers were used during a spill of heavy fuel oil from the barge Morris J Berman to remove the oil from the bottom using an air lift which is a pipe with compressed air entering near the bottom thus as it rises causing a reduction in pressure and lifting the oil to the surface. In the clear water the minimum possible sediments were removed.
In high sediment water where a diver has visibility of a few centimeters this type of work is impossible, also in areas with currents in excess of 2 – 3 knots where the diver is taken off the job continuously, work will only be carried out during slack tide this in some cases will be less than 20 minutes per 6 hours.
The depth of water where the spill occured is of huge importance. If decompression has to be done then the diver/s will have to be perfectly clean, nude when going into a confined space breathing in part pure oxygen. Dependent on the climate it can be very cold in a steel tube.
We have known since the second world war that oil and oxygen unde pressure explode very readily.
When the oil sinks, we have few resources for its removal, for this type of environment. Dredging the bottom is capable of removing the contaminated sediment being, therefore, efficient as a technique of decontamination in clear waters.
However, it causes a lot of damage to the biological community that was already affected by the oil. A large part of the biological community could also be removed together with the sediment, for this reason dredging should be avoided.
In certain sheltered locations with contaminated environments, it could take a long time to return to a healthy environment. Dredging in this case could be considered. The contaminated sediment would be removed, making possible the repopulation of the environment.
This remains a huge problem along the Lebanese coast after Israel bombed a power plant in their war of 2006.
Here is a dredging operation from 2013 Kalamazoo River, Michigan. Looking at the boom and the boat.
A few points:
1. white boom usually means absorbent.
2. Oil that sinks is to heavy to be absorbed.
3. The boom looks to be a bit to small even if was going to absorb the oil.
4. There is always someone available to take photos especially when you do something wrong.
Photograph Clark Little
Wave action can be very effective currents and tides efficiently remove hydrocarbons from the coastal regions.
Many techniques promote additional damage to the community being cleaned. Often, doing nothing, and allowing the environment to recover naturally, is the best procedure in terms of the environment. For example, on rocky coastlines and areas of bluffs exposed to the action of waves, one should give priority to natural recovery.
In the Braer case ( Shetland Isles UK), despite the large volume of oil spilled, the environment was only slightly affected by the oil. Natural cleanup has been shown to be very efficient in these types of environments.
The oil in this case was a very light crude but the weather was close to hurricane force, this turned out to be the biggest natural dispersant demonstration to date, with some 84,000 tonnes of crude dispersed in less than two weeks.
Later found in the sediments some 150 miles to the south near Fair Isle.
It is clear that the natural process of degradation by means of exposure to weather conditions will eliminate the oil rapidly in some coastal areas and that, probably the recovery will be complete in a few years dependent on the viscosity of the oil. However, the cleanup response should expect to reduce significantly the recovery time of the environment, so that the economic and tourist concerns and, principally, worries about the effects on the wildlife can also be minimised and the avoidance of problems resulting from complaints and claims from the affected parties. The choice of the technique available and its application should be made very carefully, so that all of the impacts are minimised.
In general terms, the less sensitive coasts are those with the greater potential for natural recovery such as areas heavily exposed to waves. These areas generally do not get cleaned up due to the danger to human life and it is improbable that they suffer any long-term damage.
The sheltered coastal areas are more sensitive to oil spills and also are more sensitive to damage from some cleanup measures. To this end we try to work together to find the least damaging solution to the environmental problem.
With all shoreline cleanup operations there is always conflict between what should be done and what can be done. We have to concentrate on doing the best we can for the environment and the local population which can lead to conflicts, some can be resolved and others cannot nothing is perfect.
The coastal areas also vary greatly in their value, whether in economic, recreational, educational terms or for conservation, and in their role in the marine ecosystem. Some of these environments deserve a considerable effort to be protected from oil spills. Due to the great variability in sensitivity, potential and value of recuperation, it is essential that the contingency plans be sufficiently adaptable in order to structure the response mechanisms adapted to the special condition of each coastal region.
The burning of oil and oily residues at the site itself can be done, only if it is allowed by the appropriate environmental organisation. Several factors influence the decision-making process for burning, such as the time of year, the type of vegetation, the richness of the species and the level of water in the environment.
In the event burning is necessary, there should be a controlled location with no possibilities of explosion. Oils and residues with more than 30% of water are very difficult to be burned. The heavier oils will have to sustain the burn with lighter oil to help with ignition. At the end of the process, there will be a small amount of residue for disposal is.
The heat produced by the burning has an impact on all of the sediment due to the increase in temperature, reducing all of the primary productivity. In humid areas, the effect of this irradiated heat is minimised. Another considerable impact is the black smoke cuased by the lack of sufficient oxygen for the size of the fire.
Burning is at times an effective method of removal of oil and the contaminated vegetation of the marshes without promoting damage from trampling. Spartina marshes can resist an occasional burn, because during the winter the aerial part of the plant dries out, to sprout again later. In this period the burn may be made without adversely affecting the portion of the burned plant and can stimulate its re-sprouting. However, burning is not recommended during any other season.
Empire terminal after Katrina during burn Fire out and approx. 90% of the oil burned 5 months after the burn
This series of photos were taken after damage cause by hurricane Katrina, the marsh area was in its winter stage, the burn to place in the spring obviously there is a short term problem with air quality but the amount of damage that would have been cause by manual cleanup in the area would have caused much more damage to the marsh. Net environmental balance is always used in these cases before any decisions are made.
Bioremediation versus bioaumentation
Bioremediation consists of the application of oil-degrading bacteria or nutrients to increase the natural biological breakdown of the oil. This technique has generated considerable interest for more than two decades. It is not satisfactory for the use in large volumes of oil, but it is very useful during final cleanup and in the recuperation of degraded environments.
The addition of nutrients, nitrogen, phosphorus and potassium (NPK) are necessary in order to stimulate the growth of the microbes. This technique has great potential for the recuperation of contaminated environments. When the concentration of hydrocarbons is above 10,000 mg/kg, biodegradation shows good results. It is also necessary to have, in large quantities, the presence of interstitial air and oxygen. The nutrients will accelerate the growth of the bacteria that decompose the oil.
Spill site March 1999 Spill site July 1999 Spill site August 2000
This series of photographs show how well bioremediation works for inland oil spill sites, it is much more difficult on shorelines.
In the event the contaminated oil is in the subsurface, the bioremediation agent can be diluted in water for later irrigation of the contaminated environment. The furrowing of the sediment facilitates the mixing. Packages of bioremediation agents generally have instructions for applications.
Bioremediation agents may be applied to any type of coastal environment where access is permitted and the nutrients of the soil are deficient. They are most effective in medium and combustible crude oils. The presence of asphaltenes tends to inhibit rapid biodegradation. They also have little effect in the presence of light hydrocarbons, because these compounds evaporate quickly from the contaminated environment.
Some compounds, such as ammonia, may be toxic to the aquatic environment. Their use in mangrove areas may alter the equilibrium of the system, causing an excess of nutrients and cause adverse effects to the environment. After the application of the bioremediation agents, the environments should be monitored, preferentially.
Bio-augmentation consists of the application of bacteria to the environment to increase the natural degradation of the oil. Research and experiments during oil spills show that the addition of cultures of specialised bacteria has of little or no effect. These organisms generally develop very well in laboratories, but in the field the results have not proven to be satisfactory. These bacteria do not develop rapidly due to the competition between the autochthonous bacteria that are much better adapted to the conditions of the local medium.
Not learning from the past
The main aim of an oil spill clean up is to reduce the amount of damage done to the environment.
Back in the late 1960’s when the first of the major oil spills occurred from a tanker of over 100,000 tones up until the late 1980’s humans in general did not have the same thought for the environment that we have today. Below are a few points where it seems some people do not read case histories they just make the same mistakes all over again.
Areas like this saltmarsh in
These days if it is deemed necessary to use machinery in these areas there is a need to cause the least damage.
This type of material right is used, it is based on a military design which would have to be quick, easy and effective, to spread the weight of vehicles and is later removed and taken to the next location.
Over the years we have learned techniques to reduce this amount of beach material and therefore the time and cost of the operation.
In the past mountains of beach material were removed in comparison to the amount of oil; in some cases this was up to 1 m3 of oil to 20 m3 of sand, imagine 10,000 m3 of oil on a sandy shoreline, you would have to have somewhere handy to deal with 200,000 tones of oily waste
Extreme actions were taken especially when you have a spill of 225,000 on the shoreline as in this case. Enormous amounts of oily waste were generated which took years to resolve but at the time they had little knowledge of the damage they were doing and had to be seen to be getting rid of the problem as fast as possible.
This photo right was taken during the Deepwater Horizon response showing that none of the lessons were learned or if they were have not been remembered.
Here you see excavators piling up sand where in the foreground there are just a few small tar balls.
I am sure when the tonnage figures finally come out there will be another world record as to the amount of sand removed in this case considerably more than 20 times the amount of sand to oil.
We have discussed the problems of cleaning manmade areas such as riprap. The oil gets in between the concrete or rocks and takes a long time to come out without removing the structure.
Here we have a bulldozer building a berm to stop to oil affecting the whole tidal area on the shore.
Here are 3 points to think about.
1. Making access to the oil much more difficult
2. The sand will mix the oil with the sand as it collapses with each high tide.
3. Was it necessity for the rocks to be mixed in too.
Now instead of just removing the oil the whole contaminated mixture has to be treated.
We have used beach cleaning machines for years for removing tar balls; in some case there is a need to modify the screen for very small tar balls.
These machines are used daily around the world to remove the rubbish bathers leave behind as here on Copacabana beach. They pick up the rubbish and drop the sand where it came from.
Here we have machines that pick up both tar balls and sand the mix them together then dump it in a heap for another machine to pick up and the transport it to where it will be separated.
Unless there is a rigid system in place to say exactly where the sand came from it cannot be put back. Sand grains differ greatly in size from beach to beach and from the front to the back of a beach. If sand from one beach is put on another it can cause local erosion.
This unit left is powered by two diesel generators and a 4 million Btu propane boiler is used to heat water. A wash takes 20 minutes and in an hour the unit can process 50 tons of sand to a sterile state. It covers an area 1/3 of a football pitch. Of course this is not mobile and so all the sand from the region has to be transported to the site increasing the opportunity for road accidents and raising the cost of the operation. Big is not always best!
Washing sand until it is “really white” as a spokesperson said can also cause problems. Sandy shores have life in them especially close to the sea; putting tonnes of clean white sterile sand back where it came from can kill the life that both survived the oil and the clean up.
This too has been done in the past with units placed on the beach in question and cleaned with high pressure sea water. This may have been slightly slower but it replaced the material in the correct area and the life was not cooked.
The system breaks down and fits on a truck for transport to the next location.