WA6 Fate and Effects of Energetic Compounds
202 Oregon Ballroom
8:00 AM - 12:00 PM, Wednesday
() Effect of storage on the toxicity of TNT-spiked soil material for the collembola Folsomia candida.
Schaefer, Dr. R.K.1, Achazi, Prof. Dr. R.K.1, 1 FU-Berlin, Insitute of Exotoxicology and Biochemistry, Germany
ABSTRACT- The time a pollutant has been in the soil, affects its toxicity due to its interaction with the soil matrix and/or its physical and microbiological degradation. Thus the effects of ageing have to be taken into account for the evaluation of the ecological risk of a pollutant. With the aid of suitable biotests it is possible to assess the toxicity of the original pollutant as well as of possible degradation products of unknown toxicity. This study attempts to simulate the ageing process for 2,4,6-trinitrotoulene (TNT), the mayor ammunition derived compound in soils. For that spiked soil materials were stored at 4°C and 20°C. After a set period of time (1, 2, 4, 8, 16, and 24 weeks) the toxicity of the soil materials was determined with the collembola biotest. The test organism is Folsomia candida, which is very sensitive towards TNT. In the TNT-spiked soil materials the toxicity decreased in the mortality and reproduction test. This can be the effect of microbial degradation as well as sorption to the soil matrix. The toxicity of the stored soil material was related with both storage time and original TNT-concentration. In the mortality test the decrease in toxicity manifested itself earlier than in the reproduction tests. It was faster in soil materials stored at 20°C than in those stored at 4°C. Those soil samples which showed a decrease in toxicity were analysed for their content of TNT and some of the main degradation products (2A46DNT and 4A26DNT). The mortality was high if the extracted TNT-content was > 100 mg TNT/kg soil (dw). The reproduction failed if the extractable TNT-concentration was above 19 mg TNT/kg soil (dw) or if the concentrations of the ADNTs were quite high (2A46DNT > 9 mg/kg soil (dw) and/or 4A26DNT > 13 mg/kg soil (dw)).
Key words: storage, TNT, collebola-biotest