VOLATILIZATION AND MINERALIZATION OF [3-C-14]FLUORANTHENE AFTER - SOIL INCORPORATION AND SOIL SURFACE APPLICATION

The gaseous losses of [3-C-14]fluoranthene from bare soil were measure d in a glass wind tunnel under field-like conditions. Four experiments of 14 days each were performed under individual climatic situations. In two studies, [3-C-14]fluoranthene was incorporated into the 0-1 cm soil layer (approx. 670 mu g kg(-1)), in the other two experiments [3- C-14]fluoranthene was sprayed onto the soil surface (approx. 120 g ha( -1)). The data obtained will be used for validation of the HESP comput er model (Human Exposure of Soil Pollutants). In all experiments the m ajor fraction of radioactivity (60.0 - 97.6% of the applied radioactiv ity (AR)) was recovered in the 0-2 cm soil layer. The mineralization o f [3-C-14]fluoranthene was strongly temperature dependent and slightly higher for surface application (Sigma 6.6 and 3.3% AR) than for soil incorporation (Sigma 1.9 and 5.3% AR), possibly because of stronger ad sorption in the soil and the resulting lower availability for microbia l degradation. After surface application, the volatilization of [3-C-1 4]fluoranthene was considerably higher (Sigma 33.6 and 12.4% AR) than after soil incorporation (Sigma 1.4 and 1.8% AR). The initially high v olatilization rates decreased rapidly within 2 to 3 days in all experi ments. Subsequently volatilization continued at a low level, showed a clear temperature dependence and thus followed a diurnal rhythm. Large ly unchanged [3-C-14]fluoranthene was characterized by radio-HPTLC bot h for soil and air samples.