Toxicity and biodegradability of a soil conditioner

The soil conditioner Amalgerol(R)-Premium was investigated with regard to its toxicity its effect on the growth of microorganisms and the biodegradability of its hydrocarbon components in soil. Concentrations up to the 1000-fold of the recommended amount of application were not to be toxic in water or in aqueous soil elutriate. Only a 1000-2000-fold higher concentration than the recommended amount demonstrated an inhibiting effect on the growth of E. coli, V. fischeri and a mixed population of soil bacteria; the inhibiting effect decreased with time. A lower concentration resulted partially even in a stimulation of growth. In soil, the hydrocarbon content of a 1000-fold concentration of the recommended amount of application was reduced by about 90% within 8 days at 10-30 degrees C in an open system, 50% had disappeared already after 24 h. In a closed system (gas-tight), the hydrocarbon content decreased by 24-31% after 8 days at 10-30 degreesC. The presence of a N-P-K fertilizer had no effect on the hydrocarbon loss in soil.