A low-cost optode-array measuring system based on 1 mm plastic optical fibers — new technique for in situ detection and quantification of pyrite weathering processes

Optical oxygen sensors and a sensor array were developed on the basis of 1 mm plastic optical fibers (POF). They can be adapted to a commercially available single-channel optical fluorescence lifetime measuring device. The sensors are inexpensive and show high mechanical stability. The developed sensor array for 1 mm POF shows very good reproducibility even in a low-cost prototype version. The measuring system allows long-term in situ measurement of oxygen concentrations. In a field test, the measuring system could be used successfully for the in situ measurement in the oxygen-consuming environment of a brown coal dump body. In laboratory experiments, the system was used for the observation and quantification of pyrite oxidation processes in column experiments.