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 66 of 136 The existing threshold values are fixed on the basis of the substances toxicity to humans and not on their ecotoxicity. The threshold values refer on the open water but a plurality of foreign matter was measured partly in higher concentrations in the sediment. About the impacts of these substances is known very less the more so as between different substances interactions could happen. Aggravating is the fact, that the detection limit for some substances and groups of substances is already relative high. Chronic toxic impacts and interference of natural biological processes like reproduction and search for food can not be excluded even at very low concentrations [UBR 1994]. In the UBR-study it is mentioned, that the direct discharges into the open water of Lake Constance are caused by navigation because the exhaust gases of the outboard motors are discharged directly into the lake. That way a significant amount of the emission products come into the water like polycyclic aromatic hydrocarbons (PAH) and emulsified oils. A direct connection between the amount of hydrocarbons into the water and the intensity of the shipping traffic on Lake Constance could be proved. The mixture and the quantity depend very much on the motor type and fuel. At local places high concentrations are reached. Calculations in 1980 reveal that the emissions caused by navigation lie approximately at 1120 t highly volatile hydrocarbons for the whole lake. Approximately 67 % of this emissions are caused by sport sips and 50 % by two-stroke engines. Ecotoxicological surveys have shown that the exhaust gases of two-stroke engines have high toxicological impacts to standardised biological test procedures. For the four-stroke engines the results have shown lower values. The input of polycyclic aromatic hydrocarbons result particularly from the road dust contaminated with asphalt particles. The input of these pollutants can be prevented by a purification of the surface and street effluents in special plants at the main streets near the lake [UBR 1994]. An other safety hazard is the transport of hazardous goods on the roads and rail roads near the lake. The annual transport of hazardous goods in the inflow area of Lake Constance is substantial, at approximate 3.4 million tonnes. The ratio of road to rail transport is 54:46. The most significant traffic streams are the transport of mineral oil from the Singen region to Konstanz, and further on to the area of Switzerland around Lake Constance, and from around Ulm and Freiburg to the area of southern Germany around the lake, and further on to Austria [KREUTLER et. al. 2000]. The high concentrations of heavy hydrocarbons are found also in younger sedimentation layers consist of minimum 90 % of fossil hydrocarbons. The sources of these hydrocarbons can not be named but the emission at several sources can be estimated. Motorboats are account for approximately 42 t/a, inputs of road effluents mount up to approximately 32.5 t/a, inputs from the burning of coal as well as from exhaust fumes and oil heating. An other aspect are accidents. Between 1988 and 1990 18 000 l oil were leaked in the administrative district of Konstanz. In the period 1986 to 1990 64 300 l water-endangering substances were leaked in the administrative district of Bodenseekreis [UBR 1994]. The UBR-study points out, that volatile hydrocarbons belong to the substances, to be descended from industrial manufacturing processes and are found in the sediment of Lake Constance in higher concentrations. They are used as solvents in great quantities. To these substances also belong phthalates (plasticizer in plastics) which were emitted by use. Different heavy metals were partly remobilized from the sediment if the oxygen
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 67 of 136 concentration near the sediment surface deteriorates. In 1985 approximately 1.5 t zinc, 755 kg lead and 208 kg copper reaches Lake Constance via road effluents. The main source of these emissions is the road traffic. The untreated surface waters reach the sewage water system but not a treatment plant and enter the lake unchanged. Along the busy road B 31 all the direct discharges in Lake Constance will stop not until the realisation of the planned by-pass. The waste water treatment of the textile industry from the region make problems because the state of the art according to the pretreatment is still a contentious issue. The industry is subject to the indirect discharger directive. In 1988 and 1989 it was ascertained that the threshold values were not be observed in pre-treatment plants in the administrative district of Konstanz [UBR 1994]. Besides agricultural and forestry the source of pesticide residues are also weed control methods at the railways. Official information from the DB (German railway) state that every year 1.18 to 1.3 g herbicides (diuron tender) per square meter are sprayed. This way of weed control must be stopped at the railways near Lake Constance [UBR 1994]. From 1996 to 1998 five investigations about pharmaceutical products and some byproducts take place in the catchment area of Lake Constance. The water samples from two sewage treatment plant effluents, the most important feeders of Baden- Wuerttemberg as well as from the nearshore and the open water of the "upper lake" were checked to more than 60 substances. More than one third of the substances have been proved [ROßKNECHT, HETZENAUER 2000]. The authors continue, that mainly some antibiotics, different antirheumatics and x-raying radio-opaque dye as well as the antiepileptikum carbamazine and the lipid lowerer clofibrin acid has been proved more often and in higher concentrations. With all these substances travel varying concentration levels from the sewage treatment plant effluents to the concentrations in the open water in the middle of the lake. Pesticides Load of Lake Constance and Flowing Waters In [MÜLLER 1993] the results of a two years study about the spatial and temporal distribution of pesticides are resumed for Lake Constance. The intention of this study was the result of several surveys about pesticides in the ground and surface water which have shown that different compounds occur in increased concentrations. During six sampling series in 1990 and 1991 several samples of water from the lake, feeders and outlets have been tested to 80 different pesticides and by-products of pesticides. Substances for which during the first testing period no positive results were found have not been tested in the second testing period [MÜLLER 1993]. He points out that only four substances could be found in each sampling: atrazine, desethylatrazine, simazine, and terbutylazine. Atrazine was found in the water of Lake Constance in more than 90 % of the samplings in a constant concentration of 0.03 mg/m³ and a maximum value of 0.04 mg/m³. The by-product of atrazine desethylatrazine has a detection limit of 0.03 mg/m³ and could not be found in any lake-sampling since the halfway through 1991. Before this time the concentrations were laying between 0.03 and 0.06 mg/m³. In January 1990 simazine was not provable in any sampling of Lake Constance and reached in July 1990 nearly in each sampling nearly the detection limit. Since February 1991 nearly the same amount of 0.02 mg/m³ was measured. Terbutylazine was only occasionally found in concentrations near the detection limit of 0.01 mg/m³ [MÜLLER
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D10: Impact of Contaminants - Hydromod

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