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Establishment of reproducible toxicity tests on various biochars from pyrolysis and HTC-biocoal (hydrochar) from hydrothermal carbonization (HTC)

Daniela Busch1
1 Institut für Pflanzenökologie, Uni Gießen

V 1.6 in Neueste wissenschaftliche Ergebnisse

08.07.2010, 15:25-15:45, H 8, GEO

Addition of carbonaceous organic materials to soils is currently discussed as an option to improve soil fertility and enhance C sequestration. However, before a broadscale application can be considered, possible influences on ecosystem functions and environmental conditions should be evaluated. A series of toxicity tests were established to test if biochars (from pyrolysis and hydrothermal carbonization, HTC) affected germination and early plant development in Lactuca sativa, Hordeum vulgare and Lepidum sativum, and avoidance behaviour of earthworms (Eisenia foetida). The study of short-term effects on biological organisms, based on ISO guidelines or standardized tests used for compost evaluation, shall provide information about possible influences of phytotoxic gases, toxic substances or toxic effects on soil fauna associated with application of biochars or HTC-coals. In a first step, the reproducibility of the test procedures was evaluated using the same biochar (peanut hull, Eprida, USA). Subsequently, a variety of different biochars and HTC-coals was evaluated with the established test procedures. Preliminary results indicated that fresh HTC-coals had some negative effects on short-term biomass production and lettuce, cress and barley germination rates. However, aged HTC-biocoals seem to have different effects. Furthermore, earthworms tended to avoid the HTC-biocoal (soil medium: standard soil type 3, sandy loam). In contrast, significantly higher earthworm numbers were found in biochar-containing compartments. Furthermore, first results of genotoxicity tests with two carbonaceous substances (one biochar and one HTC-biocoal) with Tradescantia plants (test according to VDI- 3957) will be presented.

Letzte Änderung 05.07.2010