D10: Impact of Contaminants - Hydromod

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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.
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 89 of 136 Concerning the measurements of water quality SEPA (1999a) points out that the quality of Scotland's waters was initially measured by chemical analysis which measured the levels of oxygen demand and suspended solids to be used to assess the impact of sewage discharges and some forms of industrial pollution. Since the 1950s, the range of chemical measurements routinely carried out has increased considerably and now includes the measurement of nutrients, metals, oil and man-made organic substances such as pesticides and polychlorinated biphenyls. SEPA (1999a) stresses that the interpretation of chemical analyses also requires a good understanding of the concentrations above which a chemical causes damage to the environment, together with how it interacts with any other pollutants which may be present. 10.5 SUMMARY OF THE SITUATION AT THE LAKES In the previous chapters the situation at the Lakes has been described. The evaluation of the available data shows that several substances have been detected during the different surveys. Very often the substances have been measured near the detection limit or in ranges being in a tolerable amount concerning the drinking water or bathing water directive. Only SCHLICHTIG et al (2001) describe in a study the situation at the Seefelder Aach in the Lake Constance catchment where three substances have been detected in higher concentrations than the set target of the LAWA. The substances diuron, isoproturon and pirimicarb have exceeded quality targets up to 200 fold. The authors blame the sewage treatment plants, the improper handling of pesticides and their use in orchard horticulture. With respect to the sewage treatment plants the study shows that the 3 investigated plants, of 10 in the whole catchment, deliver an important part of the total pesticide load of the Seefelder Aach. They also critisise the fact that there are no set targets for many substances, and some results could not be analysed. Generally, the data concerning the impact of contaminants at the four EUROLAKES can not exclude to evaluate the possibility of potential for harm to the environment. There exists much less information about the coaction of different substances.
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D10: Impact of Contaminants - Hydromod

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