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Land spreading of biosolids as a disposal option is expensive and can disperse pathogens and contaminants in the environment. This growth room study examined phytoremediation using switchgrass (Panicum virgatumL.) and cattail (Typha latifoliaL.) as an alternative to land spreading of biosolids. Seedlings were transplanted into pots containing 3.9 kg of biosolids (dry wt.). Aboveground biomass (AGB) was harvested either once or twice during each 90-day growth period. Switchgrass AGB yield was greater with two harvests than with one harvest during the first 90-day growth period, whereas cattail yield was not affected by harvest frequency. In the second growth period, harvesting frequency did not affect the yield of either plant species. However, repeated harvesting significantly improved nitrogen (N) and phosphorus (P) uptake by both plants in the first period. Phytoextraction of P was significantly greater for switchgrass (3.9% of initial biosolids P content) than for cattail (2.8%), while plant species did not have a significant effect on N phytoextraction. The trace element accumulation in the AGB of both plant species was negligible. Phytoextraction rates attained in this study suggest that phytoremediation can effectively remove P from biosolids and offers a potentially viable alternative to the disposal of biosolids on agricultural land. [ABSTRACT FROM PUBLISHER]

The distribution of Zn, Cu, Cd, Cr, Pb, Ni, and Mn in the soil, and related soil properties was studied in Abeokuta, southwestern Nigeria. Their soil pollution source was hypothesized to be automobile traffic. Consequently, their variations were assessed as a function of traffic density, distance from road and traffic, and soil depth. Soil samples were collected from the areas of high, medium, and low traffic densities at 0, 50, 100, 150, and 200 m from roadside; at depths 0–20, 20–40, 40–60, 60–80, and 80–100 cm. The potential effects of these metals on environment and agricultural activities were also assessed. Results indicated that the major sources for the metals’ contamination are emissions from vehicles. High and medium traffic volume impacted more metals of the soils. Zinc, Cu, Cd, and Cr were concentrated at depths 0–40 cm, Pb, Ni, and Mn were concentrated at 0–20 cm and appeared bound to soil organic matter (SOM). Significantly lower concentrations of metals are found at distances of 100 m and beyond. Concentrations of these metals are generally low compared with standards and their uptake by crops is not probable. However, their continuous accumulation might be a threat in the future. [ABSTRACT FROM AUTHOR]