Volatilization and Mineralization of [3-¹⁴C]Fluoranthene After Soil Incorporation and Soil Surface Application

The gaseous losses of [3-14C]fluoranthene from bare soil were measured in a glass wind tunnel under field-like conditions. Four experiments of 14 days each were performed under individual climatic situations. In two studies. [3-14C]fluoranthene was incorporated into the 0–1 cm soil layer (approx. 670 μg kg−1), in the other two experiments [3-14C]fluoranthene was sprayed onto the soil surface (approx. 120 g ha−1). The data obtained will be used for validation of the HESP computer model (Human Exposure of Soil Pollutants). In all experiments the major fraction of radioactivity (60.0–97.6% of the applied radioactivity (AR)) was recovered in the 0–2 cm soil layer. The mineralization of [3-14C]fluoranthene was strongly temperature dependent and slightly higher for surface application (σ 6.6 and 3.3% AR) than for soil incorporation (σ 1.9 and 5.3% AR), possibly because of stronger adsorption in the soil and the resulting lower availability for microbial degradation. After surface application, the volatilization of [3-14C]fluoranthene was considerably higher (σ 33.6 and 12.4% AR) than after soil incorporation (σ 1.4 and 1.8% AR). The initially high volatilization rates decreased rapidly within 2 to 3 days in all experiments. Subsequently volatilization continued at a low level, showed a clear temperature dependence and thus followed a diurnal rhythm. Largely unchanged [3-14C]fluoranthene was characterized by radio-HPTLC both for soil and air samples.