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Two Concise Reviews
FWR publishes two concise reviews related to eutrophication. The first is entitled 'Eutrophication of Fresh Waters'. It explains causes, nutrient sources, trends, impacts and remedial initiatives for the UK. The second review is entitled 'Cyanobacterial Toxins in the Water Environment'. Cyanobacteria, also known as blue-green algae, may proliferate in eutrophic water. The review describes the processes leading to the production of toxins, their effects and what is being done about them. Copies of both reviews, along with others, are available for free download.
Aquatic Eutrophication in England and Wales - A proposed management strategy
In mid-December 1998, the Environment Agency released an external consultation document on its proposals for a strategy to manage aquatic eutrophication in England and Wales. The consultation period ended in early March 1999. This document provides a good introduction to the subject and can be downloaded as a pdf file from the consultations section of the EA website.
Lough Neagh, Northern Ireland
Lough NeaghLough Neagh is the UK's largest lake and a multi-purpose resource. The Lough is a major source of drinking water and one of the most eutrophic lakes in the world due to high phosphorus (P) inputs. The P inputs to Lough Neagh have been measured and ascribed to sources. Phosphorus from sewage works was shown to account for almost half the amount entering the lake. To curtail this source, P reduction treatment was introduced in 1981 at the ten major sewage disposal works in the Lough Neagh Catchment. This was the first time P reduction treatment had been employed in the UK and it led to a reduction in P loading and improved water quality in the lake. Lough Neagh and its tributaries have been sampled at least fortnightly since 1969 and the unbroken record of nutrient inputs and water quality in the lake shows that in the early 1990's, the effects of sewage P reduction were overtaken by increasing diffuse P loads.
Loch Lomond, Scotland
Loch Lomond is a famous tourist attraction and an important drinking water supply for central Scotland. Recent scientific data suggests that the Loch may have shifted towards a more nutrient enriched mesotrophic status. The Scottish Environment Protection Agency (SEPA) has recently compiled a report on the phosphorus inputs to Loch Lomond and proposes a strategy for their control. The report is entitled "Phosphorus control on Loch Lomond" and is available for download from the publications page of the SEPA website
Point versus diffuse sources
"It is convenient to divide nutrient sources into point and diffuse categories. Most attention has been paid to tackling point sources, such as sewage treatment works, since this has proved easier than tackling diffuse sources. However, now that a programme exists for tackling sewage treatment inputs to areas of conservation importance under the habitats Directive, the Urban Waste Water Treatment Directive and the Nitrates Directive, diffuse sources are receiving more attention.
What constitutes a point or diffuse nutrient source is not always obvious. For example, atmospheric deposition and agriculture are classed as diffuse sources, as is urban runoff, but sewage treatment works are classed as point sources, even though a proportion of the nutrient load to them is diffuse in origin. Human waste to rivers via sewage treatment works is regarded as a point source, but this is derived from a population that occupies the same area from which 'diffuse' urban runoff is derived. In agriculture, a significant proportion of the pollutant load is generated from small point sources, such as a farmyard. In an agricultural context, the categorisation of nutrient loads into point and diffuse sources is largely a scale issue, with small point sources regarded as diffuse pollution on a catchment scale, but increasingly as point sources as the spatial resolution of observation increases.
Nutrient enrichment of inland and tidal waters is considered by the European Environment Agency to be one of the most important issues to facing Europe. However this enrichment is heterogeneously distributed both throughout Europe and within the UK. On a national and European basis , diffuse source-derived P is typically estimated to constitute some 40-60% of the surface water nutrient budget, while diffuse source-derived N accounts for approximately 70-80% of the nitrogen load. In groundwater, a higher proportion (often >95%) of the nitrogen budget is derived from diffuse sources."
The above text has been derived from a review entitled 'Diffuse Pollution: Sources of N & P'. Copies of the full report are available from FWR Publications (£35.00 less 20% to FWR Members).
Adverse effects of aquatic eutrophication
The main adverse effects caused by aquatic eutrophication are listed in a position paper, ADVERSE EFFECTS OF AQUATIC EUTROPHICATION, produced by the UK Eutrophication Forum. The effects are categorised in terms of the type of waters in which they occur (fresh or saline), the type of plant/algal growth involved and the types of effect.
The Centre for Environment and Society and Department of Biological Sciences of the University of Essex have conducted a preliminary assessment for The Environment Agency of the environmental damage costs incurred in England and Wales because of the eutrophication of fresh waters. Visit their website for the latest details. A paper describing the results has now been published:-
Pretty, J. N., Mason, C. F., Nedwell, D.B., Hine, R. E., Leaf, S. and Dils,R. Environmental Costs of Freshwater Eutrophication in England and wales, Environmental Science and Technology, 37, 201-208, (2003).
The Codes of Good Agricultural Practice for the Protection of Water, Air and Soil
The codes are designed to provide practical guidance to help farmers avoid causing pollution and to protect soil as their most valuable resource. The codes describe the main risks of causing pollution from different agricultural sources. Good agricultural practice means a practice that minimises the risk of causing pollution while protecting natural resources and allowing economic agriculture to continue. A Code for the Protection of Water can be downloaded from the Defra Website.

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