Marine: Cleaner Seas report
Inputs from land
Waste entering the sea
Industrial wasteIndustrial waste may contain a range of substances from dilute acids to complex organic chemicals. It may only be discharged from onshore sources where consent is given by the Environment Agency (EA) in England and Wales, by the Scottish Environment Protection Agency (SEPA) in Scotland, or by the Department of the Environment in Northern Ireland.
The consent is based, as far as possible, on the ability of the receiving water to take the waste in question without adverse environmental effects. The controlling authorities may also impose legally enforceable conditions, including strict limits on particular substances.
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Chemicals
In recent years much attention has focused on substances such as organochlorine
compounds. These substances enter the environment in very small quantities
from a wide variety of sources and are difficult and costly to detect.
Significant levels of such compounds have been found in marine species - particularly mammals and seabirds - but there is little evidence to suggest that, at the levels generally found in UK waters, they have damaged those species. Nevertheless, precautionary action has been taken to remove the most dangerous of these substances.
For example, a voluntary ban on Polychlorinated Biphenyls (PCBs) was pioneered in the UK in the early 1970s, followed by legal controls a few years later. PCB levels in UK waters are already low and have been declining for some years. North Sea states have agreed that the remaining uses of PCBs should be phased out and all existing PCBs destroyed.
Some synthetic and natural chemicals can mimic natural hormones and there is a question whether there are sufficient amounts of such chemicals in the marine environment to cause adverse effects to associated ecosystems. The UK is playing a full part in the international research effort to investigate this issue and in the development of suitable screening and testing procedures to gauge the extent of any problems.
New chemicals are being brought into use all the time and are defined as those not included on the European Inventory of Existing Commercial Chemical Substances (EINECS), which lists most substances on the market between 1971 and 1981. Before marketing a new substance, a manufacturer or importer must notify Government with details of : estimated quantities; function and use; physico-chemical, toxicological and ecotoxicological properties; recommended precautions for safe use; and proposals for classification and labelling. This information will then form the basis of an assessment of the actual and potential risks created by each notified new substance to people and the environment.
Dangerous substances
The UK has a Red List of 23 of the most dangerous substances which have
been selected for priority control including through the system of integrated
pollution control. Red List substances are toxic, do not or are very slow
to degrade in water, and are likely to accumulate in living organisms.
The Red List includes the substances on the EC List I under the Dangerous
Substances Directive and there are statutory Environmental Quality Standards
(EQSs) in place for their discharge into surface waters. Statutory EQSs
for a further 25 substances came into force on 1 April 1998. These deal
with substances produced by manufac-turing industry, as well as a number
of pesticides applied to crops.
The UK has already achieved substantial reductions of hazardous substances entering the North Sea. At the Third North Sea Conference in 1990 it agreed to seek targets for a wider list of contaminants. At the Fourth North Sea Conference in June 1995, there was a further commitment to reduce discharges of priority substances. There is also a call for on-going reductions in emissions of hazardous substances leading to a cessation within 25 years.
Radioactive substances
Radioactive discharges are closely regulated under the Radioactive Sub-stances
Act 1993 by the Environment Agency (EA) in England and Wales, by the Scottish
Environment Protection Agency in Scotland (SEPA), and by the Northern
Ireland Environment and Heritage Service.
MAFF and, in coastal waters, the EA in England and Wales, and SEPA in Scotland, carry out monitoring of marine environmental media and foodstuffs around nuclear licensed sites that dis-charge radioactive waste into the sea. This is to ensure that any doses to the public from occupancy of coastal areas and consumption of local marine food-stuffs are well below any internationally agreed acceptable limits, and that such discharges pose no risk to the environment.
Discharges of liquid radioactive waste from the reprocessing plant at Sellafield, the UK's largest source of man-made emissions, have reduced considerably in total over the years and levels of radio-activity in the sea are correspondingly lower as a result.
Due to the processing of a backlog of stored liquid waste since 1994, levels of Technetium-99 have increased. However, the maximum radiation dose to members of the public in the UK from Sellafield discharges is well within national and international limits. The dose to people eating a large amount of seafood caught in the Sellafield area is less than 15% of the 1 millisievert* annual dose limit.
* 1 millisievert = a unit of radiation dose equal to 50 times that received from a single film chest x-ray.
Sewage and Fertilisers
Other sources of contaminants entering the sea include fertiliser run-off
(nutrients such as nitrogen and phosphorous) from farmland and sewage
discharges.
The UK has for many years treated a high proportion of its sewage (around 80%), but many coastal communities have relied on the sea's ability to degrade and purify sewage discharges without prior treatment.
Sewage sludge is the residue left after treatment at a sewage works. It can be used as fertiliser and is often spread on suitable farmland. However, where suitable land is limited, particularly in the vicinity of large coastal conurbations, disposal at sea has in the past been adopted.
The Urban Waste Water Treatment Directive requires that the dumping of sewage sludge at sea should cease by the end of 1998 and sludge be re-used whenever appropriate. Alternative disposal routes include incineration, an increase in beneficial recycling to land, use as a composting agent, and energy generation. The Government is encouraging the development of beneficial uses wherever possible.
In March 1990, the Government announced that it proposed to intro-duce treatment for all significant sewage discharges into coastal waters. This policy subsequently became a requirement of the EU's Urban Waste Water Treatment Directive.
Improvement schemes under the Bathing Water Directive injected £2,000 million to improve bathing water quality. The success of this programme is shown by coastal monitoring results. In 1997, 88% of the 486 identified waters around the UK met the EU mandatory bacterial standards, compared to 76% of the 440 bathing waters identified in 1989.
Page last modified:
01 March 2005
Page published: 21 September 1988