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 68 of 136 1993]. With the exception of the feeders the same substances were found in the water of Lake Constance. The maximum values were always higher than in the lake water (atrazine 0.12 mg/m³, desethylatrazine 0.014 mg/m³, simazine 0.05 mg/m³, terbutylazine 0.03 mg/m³). On the other hand these substances were multiple not be provable especially in the Dornbirnerach and sometimes in the Old Rhine. [MÜLLER 1993] stresses, that beside the four named triazines two more substances - cyanazine and diuron - and as well the by-products desethysimazine and desethylterbutylazine were found in some samples of the feeders. In accordance with other investigations like places for drinking water samplings at the lake the results prove the occurrence of low amounts of pesticides in the water of Lake Constance. The found concentrations are obviously lower than the permitted limit values in accordance to the German Drinking Water Directive (for single substances 0.1 mg/m³ and for the summation 0.5 mg/m³) [MÜLLER 1993]. The survey did not produce alarming results. Nearly 90 % of the tested pesticides were not be provable. The total herbicides atrazine and simazine are contained non-seasonal in traces in the whole Lake. An effect of the substances ban for atrazine being in force since spring 1991 in Germany has not be recognised during this random sample inquiry. In the period May 1999 to May 2000 in the flowing water Seefelder Aach, Riedgraben as well as the sewage treatment plant effluents in Fricken, Biegensegel and Grasbeuren a continual load of pesticides have been detected. 37 of the 58 investigated substances have been found. Withal 84 % of all load res. 94 % of the measured sewage treatment plant effluents have shown pesticides whereas up to 8 different active substances per single probe have been detected. The most commonly measured substances were the herbicides diuron, simazin, isoproturon, 2,4-D, dichlorprop-P, MCPA as well as mecoprop-P, the fungicides pyrimethanil, fenarimol, cyprodinil, penconazol and carbendazim as well as the insecticides primicarb and tebufenozid [SCHLICHTIG et al. 2001]. From the catchment area of the Seefelder Aach al least 9.2 kg active substances have been entered Lake Constance. The part of the pesticide loads from the sewage treatment plants were 61,5 % of the measured total load at the estuary of the Seefelder Aach. Due to degradation processes several of the from the sewage treatment plants emitted substances could not be detected at the mouth of the Seefelder Aach [SCHLICHTIG et al. 2001]. Investigation Programme - Feeders and Measured Parameters [HETZENAUER 1997] reports about samplings at selected places in the feeders Nonnenbach, Argen, Schussen, Rotach, Mühlbach Friedrichshafen, Manzeller Bach, Brunnisach, Lipbach, Kniebach, Dysenbach, Seefelder Aach, Nußbach, Tobelbach, Stockacher Aach, Mühlbach Randolfzell, Kasernengraben and Radolfzeller Aach has been performed. In the period between January 1993 and December 1995 the heavy metals arsenic, lead, cadmium, chrome copper and zinc and adsorbed organic halogen compounds (AOX) and volatile halogenated hydrocarbon of the group of the organic pollutants and oxygen depleting substances has been analysed. The measuring method for the heavy metals was the atom absorption spectrometry (AAS) for the AOX the "AOX Automat"
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 69 of 136 (kind of measuring instrument) was used and the volatile halogenated hydrocarbons were measured with the headspace gas chromatography. Heavy Metals The feeders load with heavy metals is discussed now. For all feeders the 90-percentile for chrome lies in a range which is deemed to be anthropogenic uncontaminated. The result for lead is the same apart from the two small feeder Kasernengraben and Mühlbach Friedrichshafen. Because of its varied use zinc is an indicator for anthropogenic influences. High 50-percentile and peaks are found in the Kasernengraben and in the Mühlbach Friedrichshafen while the other feeders are minor affected. The 50-percentile values for cadmium lie under 0.05 µg/l in every feeder so they are classified to be only slightly burdened. With the exception of the Kasernengraben the concentrations for copper lie in the area of a low load in every feeder [HETZENAUER 1997]. The author continues, that the Institute for Lake Research measures selected heavy metals in the feeder Schussen since more than 15 years. In this period a reduction of the concentration of some metals are recognised. In the period 1984 till 1987 the medium concentration for arsenic has been reduced from more than 5 µg/l to 1 µg/l and is now constant on this level. The lead concentrations in the Schussen are also reduced. Both could be the result of a processing conversion of an polluter/ discharger. In general, the heavy metal contamination of the Lake Constance feeders in Baden-Wuerttemberg is low till moderate. An exception are the small feeders Kasernengraben and Mühlbach Friedrichshafen which often have higher concentrations. AOX and Volatile Halogenated Hydrocarbons The relevant 50-percentile values for the adsorbed organic halogen compounds (AOX) in 16 of the 17 tested feeders lie at 7-14 µg/l. This is a small till moderate contamination. Because of a high 50- and 90- percentile value the Kasernengraben is special. This high concentrations could be the result of sewage discharge as well as of contaminated sides from a former military use. In contrast to the other parameters, at the group of volatile halogenated hydrocarbons only five random samples are analysed in 1995. The compounds bromidchlormethan, bromoform, dibromchlormethan, tetrachlorcarbon, trichlorethyten, chloroform, tetrachlorethylen and trichlorethan have been tested. The four first named compounds always lain below the determination limit of ca. 0.1 µg/l. The other four volatile halogenated hydrocarbons were found only in some feeders, especially in the Kasernengraben (maximum value 2.6 µg/l for trichlorethylen, 1.7 µg/l for chloroform) and in the Mühlbach Friedrichshafen (maximum value 2.1 µg/l for tetrachlorethylen). Chloroform values higher than 1 µg/l are classified as an increased burden. The maximum value in the Kasernengraben is higher than this value. In the rivers Schussen, Randolfzeller Aach, Seefelder Aach, Rotach, Stockacher Aach and Nonnenbach only some volatile halogenated hydrocarbons could be measured. All the measured concentrations are lower than 0.25 µg/l [HETZENAUER 1997]. Summary of the Situation at Lake Constance Concerning Endocrine Disrupters As shown, several active substances like pesticides and heavy metals have been detected in the water of the Bodensee and in investigated feeders. Due to the numerous flowing waters in the Lake Constance catchment and the high measured pesticide loads SCHLICHTIG et al 2001 emphasising the need of further controls of the small
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D10: Impact of Contaminants - Hydromod

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