English Abstract This report describes the experiments that were carried
out, to develop a bioassay with nematodes in a polluted natural soil. The
nematode Plectus acuminatus, was cultured in 0.5% sloppy-agar with
Acinetobacter spec. as a food source. For the experiments small plastic
pots were used with 10 g soil polluted with heavy metals, from the
Budel-area. One hundred nematodes were inoculated, and exposed for 7 days
in a climate-chamber by 20 degrees C in the dark. In the first experiment
with three levels of heavy metal contamination and pH-adjustment, the
recovery of nematodes was very low (maximum 22%). The results showed that
nematodes can survive in experiments with natural soil. Also a weak trend
was found: more nematodes were caught back in the clean soil. Liming (to
adjust pH) did not seem to have an effect on survival. To optimize the
survival a second experiment was carried out. Several methodical items were
investigated (Liming, Extraction method, Food, Injection of nematodes). The
results show that the survival percentage can be optimized to an average of
79%. Additionally, the possibilities to preserve Plectus acuminatus in a
frozen state were investigated, in order to use identical genetical material
in future experiments. It appeared to be possible to revive nematodes after
freezing at -70 C degrees. The highest survival (19%), after 7 days at -70
degrees C, was found for nematodes in pure tap water.
