Scottish coastal seas support some of the most productive marine ecosystems in the world and this reflects, amongst other things, the general high quality of our marine waters.
Scotland's low population density and position on the north-west of Europe have ensured that there has been relatively little contamination of the seas and any contaminants that have been released have an opportunity to dilute and disperse. Inevitably, as in any developed country, Scotland has an industrial history and as could be expected, where industrial development in the central belt was concentrated, some water quality problems remain, some of which result from historical contamination.
The sea acts as a sink for virtually all the substances that enter fresh waters and also receives chemical contaminants from the atmosphere, some of which may not originate from Scotland. Domestic inputs of contaminants to the seas and estuaries have demonstrably been reduced in the last 30 years as improved legislation and statutory powers, and an understanding of the consequences of pollution, have enabled Scotland increasingly to regulate the discharges from key polluters.
A clean and healthy sea is, of course, not just about chemicals in the water. It also relates to all changes that can affect animal and plant life at any stage in their life cycles. Other significant deterioration in quality can come from a lack of water clarity caused by increased mud, noise from man-made sources or temperature changes caused by effluents that are significantly warmer or colder than their receiving waters.
Work to maintain and improve the cleanliness of the seas has been greatly helped by a wide range of legislation and conventions, most of which now originate from the European Union. Regulating agencies aim to use all available legislation to ensure that Scotland's seas are clean and safe and to meet the OSPAR objective to continually reduce discharges.
The recent Marine Strategy Framework Directive (MSFD) adds to this by introducing the concept of achieving good environmental status.