Umweltgeochemische Charakterisierung der niedermolekularen organischen Fracht des Flußsystems Lippe
Rivers are a sensitive and complex ecosystem hosting a diverse spectrum of organisms. Human activities have resulted in increasing river pollution due to input of organic contaminants into the river systems (anthropogenic input). The main emphasis of the present study is a comprehensive examination of anthropogenic and non-anthropogenic low-molecular weight organic compounds in a selected river system. The Lippe River (North Rhine-Westphalia, Germany) was chosen for this approach because it is located in a densely populated area with many diverse anthropogenic input sources, e.g. chemical industry, mining, agriculture and sewage. Four sample sets of river water and sediments were taken semi-annually at 19 sampling sites on a longitudinal section of the Lippe River. In order to identify a broad spectrum of organic compounds, non-discriminating methods were applied for extraction and analysis of the sample material. Gaschromatographic separation of the compounds and subsequent registration with FID/ECD as well as with MS allowed to identify a large number of low-molecular weight compounds with a high sensitivity. In this study the main emphasis was put on the investigation of the water samples. More than 100 dissolved organic compounds were identified which ranged from nonpolar constituents like aliphatic hydrocarbons to polar constituents like carboxylic (fatty) acids and phenols. Most of the organic compounds identified in Lippe River water could be attributed to anthropogenic input. Many of these anthropogenic compounds are by-products of industrial synthesis or are used as plasticizers, flame retardants, pharmaceutical drugs or synthetic fragrances. Using suitable molecular markers, effluents of sewage treatment plants were determined as the main input source for organic pollution of the Lippe River system. One major goal of this study was to investigate the organic pollution of the Lippe River on a quantitative basis. To this end 26 anthropogenic compounds of interest which were present in most water samples in concentrations above the limit of quantitation were surveyed. Features of specific interest were those related to e.g. xenobiotic attributes (e.g. ethylhexyl functional groups) or compounds with assumed physiological properties. Dissolved organic loads of the selected compounds were calculated on the basis of compound concentrations in water and river runoff on the day of sampling. The organic loads of each compound were compiled along the longitudinal section of the Lippe River in order to generate individual spatial pollution profiles. Distribution of organic loads along the river showed distinctive patterns, depending upon the input situation and physico-chemical properties of the compounds. Type 1 compounds were characterised by steadily increasing loads from the river source to the river mouth. Type 2 compounds represented the same trend but, due to large variations along the river, not as significantly as Type 1. Both types have in common that a steady input along the river, in most cases by effluents of sewage treatment plants, is taking place. Increasing loads of Type 1 compounds along the river indicate that the input rate is always higher than removal rate. This accumulation in the aqueous phase indicates the persistence of Type 1 compounds and their low tendency to partition into other phases. Their distribution along the river witnesses therefore the input situation of pollutants into the Lippe River in a very concrete fashion. The erratic distribution pattern of Type 2 compounds results from partial compensation of input by effective removal processes. The fact that loads are decreasing within a short flow distance implies that these processes take place within a short period. Consequently, it can be deduced that Type 2 compounds are rapidly degraded in the aqueous phase or tend to partition into other phases (e.g. by volatilization or adsorption to particulate matter). The third type of compounds occurred only in restricted sections of the river implying a punctual input pathway (point source). The Type 1 compounds which remain relatively stable in the aqueous phase are useful molecular markers for anthropogenic input of organic pollutants. They can be applied to track plumes from discrete pollution sources (e.g. sewage effluents). Generally, the investigation of compound distributions in natural systems provides direct information on the properties and fate of compounds which are discharged into the rivers.
info:eu-repo/classification/ddc/550, Lippe <Fluss>, Schadstoffbelastung, Niedermolekulare Verbindungen, Organische Verbindungen, Umweltgeochemie, Geowissenschaften, GC-MS, Screening Untersuchungen, niedermolekulare organische Verbindungen, organische Schadstoffe, Flußsysteme
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