WP3: Geochemical investigations into the dissemination of contaminants in conventional ammunition
The aim of WP3 is to investigate the release and distribution of organic and inorganic contaminants in seawater and sediments before, during and after the delaboration process. In addition, the degradation and degradation processes of these contaminants in contact with the seawater in the Baltic Sea are examined in laboratory experiments. The most hazardous organic and inorganic compounds of conventional ammunition are Trinitrotoluene (TNT) and its degradation products (Trinitrobenzene (TNB), amino-dinitrotoluene (ADNT)) as well as mercury (Hg), methyl mercury (MeHg) and lead (Pb), which were used in trigger units and explosive capsules (Pichtel, 2012). These substances can be released into the seawater and the surrounding sediment either due to the corrosion of the metal housings of the weapons or during the planned delaboration in the course of the RoBEMM project and ultimately incorporated by marine organisms. However, the biogeochemical cycles of these contaminants close to munition dump sites is yet not very well understood.
Aims and responsibilies
During the course of the UDEMM project, the concentrations of these contaminants (see above) in seawater, bottom sediments and organisms (WP4) are measured in the study areas (Kohlberger Heide and the Bay of Eckernförde). The water column is sampled at different depths using either a “trace metal clean” Go-Flo water creator or a “trace metal clean pump CTD” and for both particles in solution (< 0.2 µm) and the suspended particulate fraction (filtrate > 0.2 µm). In addition, sediment and pore water samples are taken from the same location as the water samples using a multicorer (MUC). The processing and chemical analysis of the samples will be conducted within 24 hours after sampling using high performance liquid chromatography (HPLC) for TNT and its degradation products. The concentrations of Hg, MeHg and Pb in the different fractions are determined using inductively coupled mass spectrometry (ICP-MS; Thermo-, Element XR and XSeries).
During the delaboration process the possible release of the hazardous compounds is analyzed using a solid phase extraction column that will be mounted outside the delaboration chamber and is developed in close collaboration with the RoBEMM project.
Furthermore, it is planned to conduct seawater and seawater-sediment incubation experiments to investigate the biotic and abiotic (degradation-) cycles of TNT and its degradation products in detail. In the first phase of the UDEMM project, the kinetics of the TNT solubility and its degradation (including its products) will be determined under controlled “Baltic Sea conditions” (strength of the UV radiation, oxygen concentration, salinity, temperature, dissolved organic matter (DOM) concentration, nitrate) inside the lab using a Chemostat. Further lab experiments will focus more on the bacterial degradation under certain “Baltic Sea conditions”, specifically the formation of TNT polymers at pH 8.
Pichtel, J. (2012): Distribution and Fate of Military Explosives and Propellants in Soil: A Review; Applied and Environmental Soil Science; Volume 2012; 33p.; http://dx.doi.org/10.1155/2012/617236