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Environmental Effects This section describes primarily the Work of the Shetland Islands Council's Environmental Health department, both during and after the spill. As might be expected this department was at the forefront of monitoring the effects of the spill on all aspects of the environment, with particular emphasis on potential effects to the Shetland community, both in terms of immediate and longer-term health risks. The Braer incident was unique in the fact that it posed problems for the environmental health and public health professions not normally associated with an oil spill. Consequently problems which were not anticipated in oil spill response plans or routinely dealt with in exercises were very much in evidence from day one. These problems stemmed from the fact that the combination of light crude oil and extreme weather conditions caused significant pollution of the air, land, and fresh water via an oil/sea water aerosol/droplet mix. Initially the pollution gave rise to a strong smell of oil and reports of irritation to eyes, noses and fears of an imminent explosion risk. Measurements taken on the first evening using a meter designed for checking explosive levels of hydrocarbons at petrol stations, however, ruled out any risks from explosion. The spill also put severe pressure on the staff and resources within the Shetland Islands Council (SIC) as a whole but in particular within the Environmental Services Department. This stress was not limited to those actively involved in the incident as the others still had to contend with the day to day problems. This situation was exacerbated as the Director and Divisional Manager of Environmental Health had key roles in the joint response being the Vice Chairman of the Management Team and the Chairman of the Environment Team respectively. Assistance was forthcoming with experts in public health provided by the Scottish Office and the Royal Environmental Health Institute of Scotland, who provided a pool of volunteers from which Officers and equipment drawn from Edinburgh District Council and Orkney Islands Council. The oil industry provided an oil vapour analyser (OVA) and staff to operate it initially and trained local staff. In addition the Shetland Islands Council contacted a consultant in occupational health. This newly formed team of SIC staff and outside help was then equipped to deal with the problems as they arose. The first decision taken in public health terms following advice from the various contacts and the team that was set up was not to evacuate the immediate area, an option which was being considered for public health and safety reasons. In hindsight this was the correct decision as no long term health implications have been found nor were there any casualties. Had an evacuation taken place there was a very real chance of a fatality through for example an old person having a heart attack, or given the weather conditions, a road traffic accident. Public Concerns The strong hydrocarbon smell following the spill and irritation caused to some people's eyes and nose lead to a very real concern about effects the oil in the air would have on people's health. This was heightened when the Marine Pollution Control Unit (MPCU) authorised aerial dispersant spraying operations to try and assist the dispersal of oil near the wreck. Unfortunately spraying this oil lead to the accidental over - spraying of people and houses upwind of the target area. Complaints were received and a revised spraying strategy was agreed. The operational height of the aircraft was reduced from 30 feet to 15 feet above the waves. There would be no spraying near populated areas and the equipment would be switched off at the end of the run and emptied before the aircraft made the approach for the next run. The revised operation was witnessed and approved by the local Councillor, MP and Director of Public Health. In parallel to this it was agreed that no spraying of dispersants would occur above the 60° North line in an attempt to protect farmed salmon cages. Public concern about spraying was increased by the refusal of the MPCU to release the chemical composition of the dispersants due to commercial confidentiality (a policy which has now been reviewed) allowing a view to be expressed that this was because of the very toxic chemicals involved. From the point of view of the Joint Response Centre (JRC) Management Team, the Environment Team and the SIC it was very frustrating that detailed information on the chemical composition of dispersants was not readily available from day one and in fact it was day four of the incident before information was to hand. In addition it was reported that members of Greenpeace were handing out leaflets letting locals know that one of the dispersants "dispolene" was banned by the Norwegians. Atmospheric Pollution There was an obvious need to carry out monitoring of the atmosphere and from day two an OVA was used to take readings in the affected area. By day six, the team set up to monitor the atmosphere had begun a sampling programme using pump samples with absorbents, deposition tiles, diffusive monitors and precipitation samples, as well as a direct reading organic vapour analyser (OVA) with a limit of detection of 1 part per million (ppm). Total organic vapours at places of habitation reached measurable levels only on 12th January 1993. The sampling locations used for the monitoring of airborne contaminants were either at houses, or other frequented places such as shops and schools, etc. The sampling was concentrated on the areas closest to the site of the wreck and other places where there was known to be significant contamination. Measurements were not taken inside houses for two reasons. Firstly the levels outside were not found to be significant and it was assumed that levels inside would be less. Secondly as there are sources volatile organic compounds such as gas cookers, central heating systems, etc., inside houses, interpretation of any results would have been difficult. Even though evidence suggested that there was no significant risk to health the SIC Environmental Services Department did issue general guidance notes for the public based on the advice to stay indoors, whenever it was not essential to be out. It is normal to try and avoid going out in severe winter gales, therefore there was little inconvenience to locals taking this advice. There are, however, some sections of the community who required to work outside for long periods of time, such as farmers. Advice to this group was to thoroughly wash off contaminants and to wear the protective vapour masks provided by the Environmental Services Department. Supplies of masks were provided at locations such as local shops. During the 9th to 20th January 1993 measurable levels of hydrocarbons were only found on one occasion. On the 11th January 1993 up to 6 ppm was measured in the vicinity of the house on Garths Ness. This was the day the Braer broke up and it is believed the levels of contamination may have been similar to those on the first day. When the OVA analyser was taken to within a few feet of oil dispersed in water on the beach or near to contaminated materials, no levels greater that 1 ppm (the detection limit of the device) were recorded. Hydrocarbon Static Monitoring Results The highest atmospheric hydrocarbon level recorded was at Garths Ness and was 6.33 ppm on the day that the Braer began to break up. The previous day the level at the same location was 0.264 ppm and the day after the level was <0.010 ppm. The corresponding benzene levels were 0.074 ppm, 0.023 ppm and <0.010 ppm. On 12th January 1993 (the day after the vessel broke up), the highest levels of hydrocarbons and benzene measured were 0.071 ppm and 0.018 ppm respectively. During the 13th to the 14th January 1993, total C3 - C8 hydrocarbons were in the range <0.010 ppm to 0.076 ppm with benzene levels of 0.010 to 0.043 ppm. A level of 2.09 ppm of C3 - C8 hydrocarbons was measured at Scat Ness in the period 15th to 16th January 1993. From the analysis it was considered that the major proportion of this was attributed to the compounds which could have originated from liquefied gas used for domestic purposes. During the 16th to the 20th January 1993 the 21 C6 - C16 results were in the range 0.04 to 0.023 ppm and all of the benzene results were less than 0.001 ppm. For comparison total hydrocarbon levels in a major city at any given rush hour are likely to be in the region of 11 ppm. The exposures of those involved in the clean up activities and in wildlife recovery were in the range 0.023 to 0.426 ppm of C6 - C16 and 0.060 to 0.187 ppm of C3 - C8 hydrocarbons. Exposures to benzene for one set of measurements were in the range of <0.001 to 0.014 ppm while another indicated levels were all less than 0.080 ppm. Differences in the detection limits are a factor of the sampling period involved and the measurement technique used. The exposures to particulate matter were in the range 0.01 to 0.67 milligrams per cubic metre with all the cyclohexane extractable fraction figures being less than 0.02 milligrams per cubic metre. Static Airborne Particulate, Deposition and Precipitation Sampling Results On the 11th January 1993 all the results were less than 0.1 milligrams per cubic metre, the limit detection of the method used at that time. During the 14th to the 20th January 1993 the results were in the range less than 0.01 to 0.53 milligrams per cubic metre. All the cyclohexane extractable material results, apart from one of 0.14 milligrams per cubic metre, were less than 0.01 milligrams per cubic metre. The cyclohexane extractable fraction was measured to estimate the hydrocarbon contact of the particulate. These results would indicate that much of the airborne particulate were not associated with the oil but would have been sea spray and general dust or soil generated material, produced by the continuous gale force winds. The results from the precipitation sampling indicated that sea spray and general dust were major contributors to the airborne contamination, as demonstrated by high levels of chloride in certain of the collected water samples and the suspended solids present. The highest chloride levels, obtained on the 18th and 19th January 1993 were associated with measurable levels of hydrocarbons, indicating that the airborne oil particulate was associated with the sea spray. The deposition plates indicated that on many occasions' substantial proportions of the deposited material was non-cyclohexane extractable. It should also be noted that not all of the cyclohexane extractable material would be attributable to the oil; there was non-oil-associated cyclohexane extractable material present in the soil. Drinking Water Pollution There was no apparent deterioration in the taste of fresh water supplies throughout the period of monitoring and no complaints of taint were received from the public. Water samples nevertheless were taken from day one and sent for analysis to a number of laboratories. Samples despatched to the different laboratories effectively overcame the transport delays brought about by the severe weather conditions. Samples were sent to the Sullom Voe Terminal laboratory on a daily basis. Although the limit of detection of the procedure used was 1 part per million of oil it was useful to carry out this analysis as a quick indication of gross pollution. The North East River Purification Board laboratory in Aberdeen was used as results could be provided within 24 hours. Samples submitted indicated that the concentration of hexane extractable material in all samples was less than 1 milligram per litre which was the limit of detection of the method. In one of the 14 samples submitted there was an elevated total organic carbon level (28 milligrams per litre). All of the other results were in the range of 4.3 to 5.5 milligrams per litre. No significant peaks were found on any of the chromatograms. The total organic carbon level of 28 milligrams per litre occurred on the 14th January and on the following day the level was done to 4.6 milligrams per litre. No explanation can be found for this value. Two samples were submitted (taken on the 7th and 13th January) to the Lothian Regional Council laboratory. Both were considered to be satisfactory and to comply with the requirements of the Water Supply (Water Quality) (Scotland) Regulations 1990. There were no detectable traces of mineral hydrocarbons (less than 0.001 milligrams per litre) in either sample. Had oil been the source of contamination of the water a pattern would be expected in the contaminants found, but the results indicated that there was no measurable effect on the water quality. Of the 47 benzene results obtained a measurable level of benzene was found (0.7 micrograms per litre) only on one occasion (16th January) and this was not associated with measurable levels of other compounds. All other benzene results were less than 0.3 micrograms per litre. Measurable levels of toluene were found in six samples (taken on the 7th and 8th January), some of which were associated with detectable concentrations of xylene. The highest combined concentrations were 1.9 micrograms per litre which compares with the standard for hydrocarbons of 10 micrograms per litre. It is know that benzene and PAHs were not detected in this sample but it is not known if other hydrocarbons may have been present. On only two occasions were measurable levels of PAHs found when the two compounds measured totalled 0.10 and 0.18 micrograms per litre compared with the 0.2 micrograms per litre standard. On all other occasions the levels of PAHs were less than the limit of detection of the method, which, depending on the sample, was in the range of 0.01 to 0.05 micrograms per litre. Only on a few occasions were levels of individual compounds in any one sample at measurable levels. The compounds may have arisen from sources which had nothing to do with the oil spill. The results of the water analyses were compared against the requirements of the Water Supply (Water Quality) (Scotland) Regulations 1990. The values observed all complied with the requirements of these regulations. Land Pollution This section looks at land pollution in terms of food safety implications and the Environmental Services responsibilities rather than the effects on crops, animals, fish or shell fish. The responsibility of food safety becomes the SIC Environmental Services Department's when food is harvested not when it is in the sea or land i.e. when it becomes food rather than a crop. In the first few days of the incidents the local veterinary officer together with the Scottish Agricultural College (SAC) adviser undertook a fairly comprehensive visual study of the perceived affected land for animal husbandry reasons. The land was classified as having heavy, moderate, slight or no contamination. This work was widely used during and after the incident by a considerable number of organisations and individuals. During the incident the SIC and Scottish Office Home and Health Department used this information to agree an area where food stuffs originated from could not be sold for human consumption. Milk was exempted as the cows were being housed inside and fed on the previous year's silage, and there was no risk of contamination. The milk, however, was sampled anyway as a precaution. It should be noted that there was no general ban on food from the affected areas in terms that the food was unfit for human consumption. The ban was based on the fact that food was or had possibly been contaminated. This was because it proved impossible to establish if for example, a contaminated turnip was unfit for human consumption, given that ground vegetables are normally washed and peeled before eating. This meant gardeners and farmers, if happy to do so, could eat their own produce. During the first harvesting season (summer 1993) before lifting the ban, samples of crops were taken just before maturity. The timing of this proved to be fairly difficult as the crops needed to be harvested quickly after sampling to ensure the goods were marketable. Two cows were taken to the fields two weeks before the others and had their milk tested. Only after these tests proved satisfactory were the rest of the cows allowed into the fields. Other similar work was undertaken on sheep and vegetables. Health Implications / Health Study The air pollution in the Braer incident and the consequential pollution of inland water and land was exceptional, and no national or internationally accepted standards are available against which to evaluate the environmental levels of the substances monitored. For certain substances, however, occupational exposure limits have been set and comparison with occupational health limits is useful. It is important however, to remember that occupational limits are set to protect against acute and chronic toxic effects of substances for those exposed for eight hours a day, five days a week over a 40 year working life. The pollution on Shetland lasted no more than a few days. It is likely, therefore, that levels of pollution in the Shetland incident would need to exceed the occupational health limits by many times over if they were to pose the same kind of risk levels. Crude oil aerosols are much more irritant than vapours, and it is to be expected that particles of higher boiling point oily compounds and the surfactants from the dispersants, possibly together with high concentrations of salt, would have produced the eye and throat irritation reported in the incident. No environmental standards are available for such aerosols. With the contaminants arising from the crude oil and the use of dispersants in the Braer incident the length of exposure meant that acute (short-term) effects were of more concern than any potential long term effect. If people were not experiencing any acute effects (which in the case of both crude oil and dispersants, would have been respiratory and eye irritation and, in heavy contamination, skin irritation), or if the effects were transitory and disappeared once the exposure was reduced, although not desirable, would be unlikely to have long-term adverse effects on health. Post-spill Health Study A health study undertaken by the Environmental Health (Scotland) Unit was started on 13 January, within ten days of the grounding (Campbell et al 1993). The entire population registered with the local general practice, who were resident in the area within a three mile radius of the site of the grounding, were invited to participate in the survey. The study comprised the recording of symptoms experienced in the two weeks prior to and in the period following the incident; the testing of respiratory function using a peak expiratory flow meter; the recording of height and weight; taking of blood for tests of liver and kidney function and for haematological screening together with a toxicological screening; and testing a urine sample for protein, blood and sugar, and for toxicological markers. Exactly the same format of testing was offered to an age and sex matched control population living in the north of the Shetland Mainland who had not been exposed to the pollution incident. Of the 635 invited, 420 responded in the test area; and a control group comprised 92 individuals. The results confirmed the anecdotal reports of headache, throat irritation, skin irritation, and itchy eyes which had begun on days 1 and 2 of the incident. No significant differences for any of the biological markers were found between those in the affected area and those in the control area, and the toxicological studies failed to show any exposures known to affect human health. The announcement of the results of the first round of testing, as well as the knowledge that the testing was to be continued, appeared to reassure the bulk of the population who were exposed. Personnel involved in the wildlife recovery, in the clean-up activities and the Police were not included in the health monitoring programme unless they were residents of the area covered by the study. The Direct Labour Organisation (DLO) involved in the clean-up are Shetland Islands Council employees. Assessments, as required by the Control of Substances Hazardous to Health Regulations 1988, were carried out for personnel involved in the wildlife recovery and in the clean-up activities. They were provided with personal protective equipment including overalls, boots, gloves and respirators. Advice was given to them and others working outdoors on the precautions to take to minimise exposure and on the actions to take if contamination occurred. Further studies were carried out on behalf of the SIC in summer 1993 and winter 93/94. This found levels of hydrocarbon in Shetland during February 1994 to be similar to those reported for a rural site in England. The levels were typical of the background that would have been measured prior to the Braer incident. On the basis of current information it is likely that the running annual average benzene level in Shetland, even taking into account the Braer incident, is less than the 0.005 ppm Air Quality Standard proposed by the Expert Panel in Air Quality Standards. The winter 1994 survey also indicated that much of the airborne particulate was not associated with oil but would have been sea spray and general dust or soil-generated material. |
Oil spray being blown ashore. |
Sampling with an oil vapour analyser at residential properties. |
Oiled debris being washed ashore. |
Large amounts of Hay was shipped to Lerwick for affected livestock. |
Dispersant spraying gave rise to some public concerns. |
Oil contaminated sand being removed from Quendale beach in January 1993. |
Quendale beach in summer 1993. No visible signs of oil & livestock back near the wreck site. |
braer.net |
M.V. Braer grounding and oil spill Garth's Ness, Shetland, 5 Jan 1993 |
The Braer runs aground Oil spillages are most frequently in the news when tankers run aground or are in collisions. In January 1993, an oil tanker taking 85,000 tonnes of light crude oil from Norway to Canada ran aground on rocks at the southern tip of the Shetland Isles. Gales and strong seas prevented other ships coming alongside to pump the oil off and, as the tanker broke up, the oil spilled into the sea. What was threatened? The seas off Shetland support a huge variety of marine life including shellfish, sea birds, fish, seals and otters. Many parts of the coastline have been designated as Sites of Special Scientific Interest (SSSIs). Commercial salmon farms along the coast were also at risk, as the oil pollution threatened this multi-million pound industry. In addition, it was feared that the strong winds blowing spray onshore could contaminate grazing land for sheep adjacent to the coast and, if inhaled, the spray could be a health risk to the people of Shetland, causing respiratory problems. What emergency measures were taken? The fact that there were several hours between the Braer breaking down and the vessel hitting the rocks and breaking up allowed time for emergency plans to be put into operation. (Every part of the British Isles is covered by emergency plans drawn up by central government and local authorities.) The marine, environmental and legal departments of the Shetland Islands council were all involved, as were representatives from national government (the Departments of Transport and Environment) and members of voluntary organisations. As an emergency measure, a fisheries exclusion zone of several hundred square miles was enforced, in which fishing was banned. Grazing sheep were moved from coastal pastures, and fish sales were banned from the salmon farms affected. Fortunately, the pollution problems were not as disastrous as first feared. There was no significant mortality of sea mammals due to 'Braer' oil. Plants in some fields near the coast were contaminated, some islanders reported throat and skin irritations. About 1,600 sea birds were found dead during the oil spill. The total bird mortality is likely to have been higher but represents a small proportion of the Shetland bird population. The crude oil was of a 'light' grade and the slick broke up and dispersed more quickly than would have occurred had it been a heavy grade oil. The key, however, was the weather. Strong storms, even by Shetland standards, raged for weeks during and after the accident and helped to disperse the oil naturally. An official report into the environmental impact of the Braer oil spill concluded: "Overall, the impact of the oil spill on the environment and ecology of South Shetland has been minimal. Adverse impacts did occur but were both localised and limited. The resilience of ecosystems and species populations has already been powerfully demonstrated, and provides confidence and reassurance for the future." Source: The Environmental Impact of the Wreck of the Braer, published by The Scottish Office, 1994. |
In the case of the Braer environmental damage was largely limited by natural phenomena. In other locations, and under less favourable circumstance, the damage could only be limited through human intervention, which is not always successful. |
Shetland oil spill did little harm The Braer oil spill was not a disaster, according to the group set up by the Scottish Office to examine the ecological effects of the tanker accident in the Shetland Islands. Although 85 000 tonnes of crude oil were spilled when the Braer went aground in January, early prophesies of doom appear not to have been fulfilled. The report presents data from environmental monitoring in the three months since the accident. 'Initial results suggest that populations of fish, plants and birds were not affected, even locally, to a degree which might have threatened their survival,' it says. Around 1500 dead seabirds were recovered in January, but this is a low toll compared with other major oil spills. The spill seems to have had no effect on sea mammals. However, the group acknowledges that three months is a short time: 'The ecological implications of a spill of this magnitude are unlikely to be transitory, and monitoring over a longer period will be needed before the full range of effects of the oil spill can be determined.' The oil spilt from the Braer did not form a slick, but was dispersed by the violent mechanical action of the waves. According to the report, around 30 per cent of the oil has been deposited in the sediments of two basins, around 10 500 tonnes to the west of the South Shetland peninsula and around 12 500 tonnes to the southeast of Fair Isle. This oil will slowly break down, but little is known about the ecological implications of this process. The group is also puzzled about why a fine spray of oil fell over the island in the early days of the spill, and it recommends research into how the spray could have formed. It concludes that the level of air pollution after the spill was extremely low despite the oily mist. Friends of the Earth Scotland dispute this. It says there is some contradiction in the figures and that the island was poorly equipped to monitor atmospheric pollution. From issue 1879 of New Scientist magazine, 26 June 1993, page 8. http://www.newscientist.com/arti cle/mg13818791.400-shetland-oil -spill-did-little-harm-.html |
Petroleum-based hydrocarbons can negatively impact marine life at concentrations as low as one part per billion.The lighter fractions of oil, such as benzene and toluene, are highly toxic, but are also volatile and evaporate quickly. Heavier components of crude oil, such as polycyclic aromatic hydrocarbons (PAHs) appear to cause the most damage. While they are less toxic than the lighter volatiles, they persist in the environment much longer. A heavy oil spill can also blanket shoreline ecosystems, preventing gas exchange and blocking light. The oil can mix deeply into pebble, shingle or sandy beaches, where it may remain for months or years. |