Temporal variation of PCDD/PCDF levels in environmental samples collected near an old municipal waste incinerator

In 1996 and 1997, the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in soil and herbage samples taken from 24 sites in the vicinity of an old municipal solid waste incinerator (Montcada, Barcelona, Spain). To determine the temporal variation in the concentrations of PCDD/Fs, recently 24 soiland 24 herbage samples were again collected at the same sampling points and analyzed for PCDD/F levels. In the currentsurvey, PCDD/F concentrations in soils ranged between 0.06 and127 ng I-TEQ kg^-1 (dry matter), with median and mean values of 4.80 and 9.95 ng I-TEQ kg^-1 (dry matter), respectively. In turn, the levels of PCDD/Fs in herbage samples ranged from 0.40 to 1.94 ng I-TEQ kg^-1 (dry matter), with median and mean values of 0.86 and 0.95 ng I-TEQ kg^-1 (dry matter), respectively. The comparison with the data obtained in 1996 and 1997 show that while PCDD/F concentrations in herbage samples decreased substantially during the last two years, no significant differences in the levels of PCDD/Fs in soils were noted. On the other hand, the potential intake of polluted soils from the vicinity of the plant would not imply any significant health risk for the general population living in the area under influence of the facility.