Trends in the levels of metals in soils and vegetation samples collected near a hazardous waste incinerator

In 1998 and 2001, the levels of a number of elements (As, Be, Cd, Cr, Hg, Mn, Ni, Pb, Sn, Tl, and V) were determined in 40 soil and 40 herbage samples collected near a new hazardous waste incinerator (HWI) (Constanti, Catalonia, Spain). In 2003, soil and herbage samples were again collected at the same sampling points in which samples had been taken in the previous surveys. During the period 1998-2003, As, Be, Cr, Ni, and V levels showed significant increases in soils. In contrast, the levels of Cd, Hg, and Sn significantly decreased. With respect to herbage, while Cr, Mn, and V concentrations significantly increased, those of As levels diminished. On the other hand, human health risks derived from metal ingestion and inhalation of soils were also assessed. In relation to noncarcinogenic risks, all elements presented a value inside the safe interval. In turn, Cd and Cr were also in the safe interval of carcinogenic risks, whereas in contrast As levels clearly exceeded the regulatory limits concerning carcinogenic risks. According to the results of the previous (2001) and current (2003) surveys, the fluctuations in the metal concentrations suggest that the influence of the HWI is minimal in relation to other metal pollution sources in the area.