Toxaphen in der Umwelt

Residue analysis of toxaphene has been difficult because of the complexity of the technical mixture consisting of a high number of compounds with very similar structure and differing chlorine content. Furthermore, the composition of toxaphene in environmental samples varies widely and is normally not related to that of the technical mixture. Therefore, quantification of single components in environmental samples was impossible. After the isolation and identification of a great number of components during the last decade, enough standards are available for the reliable quantification of toxaphene in all environmental compartments. Recently, most research has been performed on the separation of chiral components of toxaphene with a view to identifying the degradation mechanisms and distribution pathways.     

Toxaphen in der Umwelt

Toxaphene is a mixture of more than 200 polychlorinated C₁₀-terpenes. Due to its persistence and long-range transport, it is distributed all over the world. Many of the components are very stable under environmental conditions, while others are easily degraded by UV-light or microorganisms. The main conversion pathway is reductive dechlorination and dehydrochlorination; oxidative degradation possibly occurs only after previous dechlorination. Accumulation especially in the aquatic environment has led in many cases to high residue levels in fish, marine mammals, and sea birds of the northern hemispere. Toxaphene is mutagenic in the Ames test and of high toxicity for fish, but few data are available on the toxicity of single components or their mode of action.     

Arzneimittel in der aquatischen Umwelt

The German Environmental Advisory Council evaluated German water protection policies in its last environmental report (2004) concluded that despite some great successes in this area there is still considerable need for action. Specifically, diffuse nutrient and chemical substances inputs remain an unsolved problem. The contamination of surface and groundwater with pharmaceuticals has been identified as an environmental risk increasing in pertinence. Pharmaceuticals and their metabolites are being detected in the whole aquatic environment, which they enter through sewage, soil contamination by agriculture, and waste storage facilities. Different pharmaceuticals have been tested for acute toxicity on various aquatic organisms, but almost nothing is known about chronic toxicity of these contaminants. This knowledge, however, is essential for estimating the ecotoxicological potential of pharmaceutical residues. In the opinion of the Environmental Council different strategies are necessary, to reduce the contamination of the environment with pharmaceuticals. Farmers should refrain from using pharmaceuticals for prophylactic purposes or from using hormonally or antibiotically active substances in livestock feed additives, so as to reduce inputs of veterinary drugs. As regards human medications, packaging should better correspond to appropriate dosage amounts, and environmentally responsible disposal measures should be followed. Still under discussion are a programme for the risk evaluation of existing pharmaceuticals and a ban on the use of sewage sludge in agriculture. In the future, improvement of sewage treatment facilities, for instances through membrane technologies, will offer further potential to reduce inputs of hazardous substances.     

Wassertechnische Strategien zur Reduzierung der Trinkwasserbelastung durch Arzneimittelwirkstoffe

Results The available research results concerning the application of innovative methods of wastewater and drinking water purification to eliminate pharmaceuticals are summarized in the present paper. An increase of the activated sludge (aerobic sludge) age to 8–10 days in treatment plants can improve the metabolization of less persistent pharmaceutical agents whereas expansion of the sojourn time beyond 10 days will not result in a remarked increase of degradation for most pharmaceutical substances. First results have shown that wastewater treatment plants with integrated membrane bioreactors (MBR) using micro- and ultrafiltration membranes do not provide significantly better results compared to the conventional wastewater treatment plants with respect to the removal of organic micropollutants (including pharmaceutical residues). The use of powdered carbon in biologically treated wastewater is able to reduce pharmaceutical residues up to 80?% in the run-off water. Pilot studies scrutinize the treatment of highly contaminated effluents via catalytic photooxidation. Regarding the suitability of the method to reduce the contamination of drinking and wastewater with pharmaceuticals yet only few data from laboratory scale testing are available. Activated carbon filtration is preferably used for drinking water treatment. Primarily against the background of disinfection, ozonation is widely used for drinking water treatment, but for wastewater treatment the method is still at the experimental stage and will hardly become of practical importance because of high costs. Sustainable wastewater separation is grounded on decentralized concepts by considering material cycles (recycling) at the place of origin. In the long term, separation measures can significantly contribute to declining drug concentrations in drinking water. Regarding the quarrying of drinking water by bank filtration water, river water or artificially enriched ground water, end-of-pipe techniques are vital. Most commonly, activated carbon or activated carbon combined with ozonization is applied and assures a high drinking water quality. Discussion The advantages and disadvantages of the different water treatment methods mainly concern the varying degrees of effectiveness with respect to the elimination of very persistent pharmaceutical agents, the generation of problematical metabolites and additional waste materials, hygienic problems, energy needs and the necessity to employ appropriate technical staff for operation. Although the biodegradation of very persistent drugs cannot be enhanced by an extension of the activated sludge age, this modification should be considered in sewage plants to reduce the contamination with less persistent medical agents. Compared with conventional wastewater treatment, membrane bioreactors provide the advantage of a better control of biological activities on the plant and a comparably small plant size but high investment and operation costs. Additionally, pharmaceuticals such as carbamazepin are only insufficiently removed from wastewater by membrane bioreactors. The regular use of powdered activated carbon in sewage treatment plants would also increase the costs of wastewater treatment and would additionally exclude the further use of sewage sludge in agriculture. Currently, in Germany the further use of sewage sludge is handled differently by the Federal States and discussed controversially. The implementation of ozonation as an additional treatment method in wastewater treatment plants is not realistic because of cost concerns. Additionally, the method produces analytically as yet not assessed metabolites with unknown (eco-)toxicological impacts. For this reason ozonation should currently not be applied unless the reaction products are removed subsequently by filtration through activated carbon. For industrial sewage photooxidation is in a state of testing but an application for municipal wastewater is, up to now, out of question. When river bank filtration is used for the supply of drinking water the use of activated carbon for purification should be essential. The lifetime of the filters is often defined by the filter capacities to eliminate radiocontrast media (e.?g., iopamidole, amidotrizoic acid). Many water supply companies already apply the ozonization prior to activated carbon filtration which supports the elimination of pharmaceuticals from the sewage. The unique developmental potential of the wastewater separation can be seen in the possibility to link up these methods with sustainable exploitation techniques and concepts (re-use of sanitized water, production of fertilizer, compost and biogas). Wastewater separation will not make ‘middle/end-of-pipe’ techniques dispensable but will make their handling more effective because concentrations of pharmaceutical agents are higher in separated effluents compared to those usually found in municipal wastewater, which in mixing sewage systems is even diluted by surface runoff. Conclusions Following today’s state of knowledge activated carbon filtration (eventually coupled with ozonization) is best suited to remove drug residues and other xenobiotics from raw water. Water works that do not apply the activated carbon filtration technique for cleanup of bank filtration water should consider an upgrade. The ozonization is primarily required for disinfection of the water. As no acute health hazard proceeds from drinking water contamination by pharmaceuticals at the present time, the upgrade of wastewater treatment plants by one of the aforementioned innovative methods is currently not required in view of drinking water quality. This offers the opportunity to develop sustainable approaches that already aim to reduce drug contaminations of wastewater and hence of ground-, surface- and drinking water. Recommendations and perspectives On a short- to mid-term perspective enriched sewage of hospitals, nursing homes and other medical facilities should be collected and treated separately. From a technical point of view the conditioning of separated hospital effluents (yellow- and greywater) via activated carbon or membrane filtration is possible but should be combined with disinfection. On a mid- and long-term scale sustainable sanitary concepts based on wastewater separation (black-, grey- and/or rainwater) associated with the recycling of mineral nutrients (nitrogen, phosphorous and potassium) should be realized for development, industry and trade areas, buildings with public lavatories, airports, motorway service areas, and large office and hotel buildings. Strategies focusing primarily on up-grading of municipal wastewater treatment plants are currently existing but the related technologies are largely in a test phase. This is why a particular technique should not be favored at the moment. The combination of various techniques (i.?e., ozonization combined with activated carbon filtration) is known to be very efficient for the removal of pharmaceutical residues from water, but the combination cannot be expected to become of importance in treatment of domestic wastewater because of high costs. Moreover, improvement of wastewater treatment technologies to remove pharmaceutical residues will not make the employment of end-of-pipe techniques in water works redundant and therefore will not lead to saving of expenses.     

Körperpflegemittel in der aquatischen Umwelt

Personal care products (PCP) are produced and used in enormous amounts world-wide. In the early 1990s, the annual production volume was more than 550.000 metric tonnes for Germany alone, where liquid bath admixtures, soaps, skin care products, shampoos and dental care products represented the main use patterns of PCPs. These preparations and their ingredients are quasi-continuously introduced into the aquatic environment during regular use, preferably via municipal wastewater treatment plants, and may reach concentrations in the ng/l or μg/l range in surface waters. Furthermore, considerable persistence and bioaccumulation potential has been shown for a number of PCPs (e.g. musk fragrances, disinfectants, antiseptics, some repellents, sunscreen agents). Except for the most important detergents and surfactants used in PCPs, the possible consequences of a chronic exposure of aquatic organisms to these compounds have not been investigated systematically to date. The information on the occurrence of PCPs in different environmental compartments is also rather fragmentary. It is the main objective of this article to provide an overview on the available literature concerning the environmental chemistry and ecotoxicology of selected PCP ingredients (e.g. fragrances, preservatives and antioxidants, disinfectants and antiseptics, repellents, sunscreen agents) The set of data on the occurrence and concentrations of PCPs in the environment and the effects in representative aquatic organisms is insufficient for the majority of the groups of substances considered and does not allow an assessment of their environmental risk. The example of musk fragrances, which represent one of the better analysed groups of PCP ingredients, shows that these compounds tend to accumulate in sediments and biota (including human beings) due to their inherent physicochemical properties, and are likely to attain considerable concentration levels. However, the knowledge about effects in aquatic organisms is rather incomplete and partially contradictory. Furthermore, detailed investigations of their potential reproductive, neuro-, immuno-and genotoxicity are lacking not only for musk fragrances, but also for the overwhelming majority of other PCP ingredients.     

Arzneimittel in der Umwelt: Umweltschutz im Arzneimittelrecht

The purpose of medicinal products is to act effectively on living organisms. If they reach environmental compartments it should be taken into account that they may have effects on biota in these compartments. Legislation on medicinal products has given little consideration to the risk that medicinal products may pose to the environment. In the near future there will be some progress according to amendments to the relevant legislative provisions.     

Perfluorierte Tenside (PFT) in der aquatischen Umwelt und im Trinkwasser

Recent scientific research on perfluorinated surfactants (PS) revealed their ocurrence in German surface and drinking waters (Skutlarek, Exner, Färber 2006). Since several years, PS have been found in the global environment, especially in animal and human tissues. PS possess extreme persistence against microbiological and chemical degradation and are able to bioaccumulate in animals and humans (Houde et al. 2006). PS concentrations (sum of 12 components) in the Rhine river and its main tributaries were determined below 100 ng/L, but the rivers Ruhr (tributary of the Rhine) and Möhne (tributary of the Ruhr) showed remarkable high concentrations (Ruhr: up to 446 ng/L, Möhne: up to 4385 ng/L). The maximum concentration in drinking waters was 598 ng/L with the major component perfluorooctanoic acid (PFOA). The PS concentrations decreased similarly to the PS concentrations of the raw waters along the flow direction of the Ruhr river. Therefore it seems to be necessary to install legal regulations for these compounds.