D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 88 of 136
Water-based activities are of particular importance in Loch Lomond. Boating can increase
erosion at unofficial launching sites and sheer overcrowding may be a problem
in some popular areas. fuel spillages from powered craft may cause water pollution and
disposal ofchemical toilets' contents may be a problem for larger motor-cruisers
[SEPA]. A maximum of 1.275 boats were counted using the lake on one day during
1999, the highest figure since monitoring began in 1989. This increase in powered boat
traffic has led to concerns over a number of possible detrimental effects ranging from
boat engine hydrocarbon emissions impacting on water quality, to boat wakes causing
damage to aquatic plants in shallow waters and exacerbating problems of shore erosion.
More detailed information is not available at the moment but in general the situation at
Loch Lomond is not as serious as at the other three Lakes because here the interference
by humans is not so important.
The Situation in Scotland Concerning Endocrine Disrupters
Natural hormones in drinking water are of little concern in Scotland because there is
only one location where a sewage outfall enters a water course above the point where
water is taken for a public water supply. Effluents from some large sewage treatment
plants also discharge into rivers and estuaries and natural hormones, excreted by
women, may have feminising effects on male fish as has been found in rivers in England.
In addition, Scotland has a large amount of wool, textiles and electronics industry
and the waste waters from these, which may contain alkyl phenol ethoxylates (APEs),
enter the river and tidal waters where they may have an adverse effect on fish and
other aquatic life. A survey by the Scottish Environment Protection Agency (SEPA) in
1996 showed that EDCs were present in some areas but at concentrations below the
'no effect' level. The results also showed that at 13 sites this level may be exceeded at
certain times. SEPA points out that there have been no reports of any adverse effects
on the fish in the rivers receiving these effluents, but there has been no systematic investigation
yet carried out to confirm this [SEPA 1999b].
The great majority of freshwater lochs in Scotland are of high water quality. Of those
which have some degree of pollution, diffuse causes of pollution such as acidification,
diffuse agricultural pollution and forestry were responsible for 80 % of polluted lochs,
says SEPA in its report "Improving Scotland's Water Environment. SEPA (1999a) continues
that only three lochs are currently listened in the poor or seriously polluted categories
and only one of these has a reasonable prospect of being improved to fair water
quality by the end of 2005. Sewage effluent and freshwater fish farming are the only
significant point source discharges to Scottish lochs. Diffuse agricultural pollution and
urban drainage are also among the top four sources of river pollution in all regions. The
diffuse agricultural pollution results from the run-off of pesticides, organic waste, soil
and nutrients from agricultural land. SEPA said, that drainage from roads, yards and
roofs in urban areas is typically contaminated by metals and oils. Concerning the industrial
effluent SEPA says that in rivers industrial effluent affects only about 2 % of the
polluted river length and is ranked as seventh in the list of sources of polluted river waters.
The largest single identifiable sector causing pollution to rivers is the textile industry.