Das Komplementsystem: Ein Funktionsträger für Infektabwehr und Immunregulation

Complement is a physiological constituent of bloodplasma. In its activated state complement is able to stimulate various cells for special performance, e.g., monocytes, macrophages, granulocytes, platelets, but also T- and B-lymphocytes. The biological functions of the complement system cover the following areas: induction of inflammation, defence against microbial infections, handling of immune complexes, and modulation of the immune response.     

Bestimmung von Nitrodiphenylaminen und verwandten Verbindungen im Sickerwasser einer Rüstungsaltlast

Goal, Scope and Background

Nitrodiphenylamines can be found at abandoned military sites where the explosive 2,2′,4,4′,6,6′-hexanitrodiphenylamine (hexyl) or diphenylamine as a stabilizer of smokeless powder was handled. Aim of the present study is the development of HPLC methods for the analysis of contaminants which can be expected in particular under aerobic conditions at premises which are contaminated by nitrodiphenyl-amines and related compounds.

Methods

A list of 13 compounds which can be expected at these explosives factories was deduced from literature studies. HPLC methods were developed for the analytes. Water samples from the unsaturated zone of a former hexyl-producing factory were collected by suction cups and the material was analysed according to these procedures to demonstrate the practicability of the new methods and to verify the existence of the postulated compounds in the environment of the former nitration plant.

Results and Conclusion

The new HPLC methods are suitable for the exploration of sites contaminated by nitrodiphenylamines. Beside some hexyl its intermediates 1-chloro-2,4-dinitrobenzene, 2,4-dinitrodiphenylamine und 2,2′,4,4′-tetranitrodiphenylamine were identified in the leachate water.

Recommendation and Perspective

It is advisable to include at least these 4 compounds in the examination of former hexyl-producing plants. Several unknown peaks were observed in the HPLC-chromatogram. It is recommendable to perform further investigations of the unidentified compounds to compile a final list of analytes for military sites polluted by nitrodiphenylamines.     

Fate and transport of N-nitrosamines under conditions simulating full-scale groundwater recharge operations.

The key objective of this study was to investigate the attenuation mechanisms of seven N-nitrosamine compounds at environmental concentrations and under conditions relevant to groundwater recharge operations. The study used a combination of controlled laboratory-scale soil-column experiments and groundwater monitoring at a full-scale river-bank filtration facility. Findings of the controlled column experiments suggest that N-nitrosodimethylamine and six other N-nitrosamines (N-nitrosodiethylamine, N-nitrosomethylethylamine, N-nitroso-n-propylamine, N-nitrosodi-n-butylamine, N-nitrosopiperidine, and N-nitrosopyrrolidine) are biodegradable under oxic and anoxic oxidation-reduction conditions. Half lives determined in this study for the targeted compounds varied between 1.3 and 7 days, which will ensure a removal to below detection limits (< 2 ng/L) within short travel times in groundwater recharge systems. Findings of this study suggest that complete removal of N-nitrosamines requires the presence of an adapted biocommunity, which will be established over several weeks to months.