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The article discusses lead contamination in soils as a major concern because it is toxic to humans and animals. Phosphate can bind lead and reduce the bioavailability and leachability of lead in soils. The authors tested different methods of applying phosphoric acid and phosphate rock as phosphorus sources to a soil, including applying as a layer, mixed with soil, and applied in one or two amendments. They concluded that mixing both phosphoric acid and phosphate rock with the soil at the same time was the most effective method for remediation in immobilizing lead while minimizing soil acidification.

This article reports that Chinese brake fern is a hyperaccumulator of arsenic (As) that grows naturally on soils in the southern United States. The fundamental explanation for improved uptake of poorly mobile elements by arbuscular mycorrhizal (AM) plants is that they have a better distributed absorbing surface area in the soil than do nonmycorrhizal plants. At harvest, percentage root length colonized by AM fungi, frond and root dry masses, and As and P concentrations were determined. Root length colonized by AM fungi ranged from 10 to 42% in treatments receiving the community inoculum. Mycorrhizal colonization had a significant and positive effect on frond dry mass at the highest level of As amendment and with addition of phosphorus. The fact that mycorrhizal colonization significantly increased the biomass of Chinese brake fern at high As levels suggests that inoculation with mycorrhizae may be a viable technology to improve the efficiency of plant arsenic uptake. In treatments amended with As, the effects of mycorrhizae on plant P concentrations as well as contents were more varied.

Focuses on weathering of lead bullets and its effect on the environment at several outdoor shooting ranges in Florida. Analysis of soil, plant and water samples; Presence of hydrocerussite in the weathered crusts and berm soils in the shooting ranges with alkaline soil hydrogen-ion concentration; Observation of elevated total lead concentrations in bermudagrass and in surface water.

Understanding trace metal leachability is important for successful land application of papermill residues. Trace metal leachability from papermill ashes (Ash 1 and Ash 2) and papermill sludge (Sludge), and the effects of a soil on their leachability were determined by leaching the three papermill residues packed on top of a soil in a column. The leachates were analyzed for pH, electrical conductivity (EC), dissolved organic carbon (DOC), and concentrations of six metals (Cd, Cr, Cu, Pb, Se, and Zn). Ash 1 behaved significantly differently from Ash 2 during the leaching experiment, primarily due to its high pH andNa contents. Application of papermill residues significantly increased the pH, EC, and DOC concentrations in leachates, with Ash 1 havingsignificantly greater impacts than Ash 2 and sludge. Soil columns under alkaline leaching of Ash 1 appeared bleached due to the dissolution of solid-phase organic matter. Significant amounts of Zn were leached from all papermill residues, whereas significant amounts of Cr, Se, and Cu were leached only in the Ash 1 treatments. The presence of a soil (especially a Bh horizon) generally enhanced metal leachability in the Ash 1 treatments due to the extremely high pH or Ash 1, whereas it decreased metal leachability in the Ash 2 and sludge treatments. Thus, organic matter enhances metal sorption when present as a solid phase, but it increases metal leachability when present in dissolved form under alkaline conditions. [ABSTRACT FROM AUTHOR]

Lead distribution in 11 contaminated soils among five physical size fractions was studied. Lead was present in elevated concentrations inthese soils, ranging from 198 to 12 523 mg kg-1. AlthoughPb in these soils was randomly distributed among the five size fractions studied, it was slightly concentrated in the silt and clay (< 53mu m) fraction with some exceptions. Several single chemical extractants were used to evaluate Pb availability in the contaminated soils.The effects of incubation and phosphate rock on Pb availability werealso investigated. Significant amounts of Pb were extracted with allthe extractants. The extractability increased in the order: H2O < Ca(NO3)2 < HOAc < EDTA-NH4OAc. The percentage of Pb extracted generally decreased with increasing incubation time as the soils gradually lost moisture during incubation. Net extractable Pb reduction with incubation time was not correlated with soH pH, organic matter, or total Fe and Mn contents in soils. Reduced Pb extractability with incubation may be attributed to precipitation/adsorption of Pb, rendering Pb less available. Addition ofphosphate rock reduced Ca(NO3)2 and HOAc extractable Pb from Pb-contaminated soils, but had little effect on EDTA-NH4OAc extractable Pb. Net extractable Pb reduction by phosphate rock was not correlated with soil pH, organic matter, or other metals such as Zn, Cu, Ni and Cd in soils, but it was highly correlated with total Pb (r = 0.7). Our results indicate that physical- chemical speciation of Pb-contaminated soils can be a useful tool in evaluating Pb availability. [ABSTRACT FROM AUTHOR]

Concentrations and distributions of 11 elements Hg, Cd, As, Cu, Cr, Pb, Ni, Zn, Mn, Al, and Fe in 40 Florida soil profiles (94 soil samples) were investigated. The soils were classified as Spodosols, Entisols, and Ultisols, representing major mineral soils in Florida. The geometric mean concentrations of Hg, Cd, As, Cu, Cr, Pb, Ni, Zn, Ma, Al, and Fe in surface soils (A horizons) were 0.0042, 0.21, 1.1, 3.7, 3.9, 4.1, 6.5, 12, 25, 730, and 820 mg kg-1, respectively.Metal concentrations in these soils were lower than those of published values of Florida agricultural soils and U.S. soils. Metal contents, excluding Cd and Mn, were strongly correlated with clay content (r= 0.35--0.77), and some metals (Cr, Ni, Pb, and Al) were correlated with cation exchange capacity (r = 0.23--0.35). Metal distributions in soils, therefore, reflected parent-material and pedogenic factors determining clay content variations between and within soil profiles. Generally, metal contents in soils decreased in the order of Ultisols> Entisols >/= Spodosols and Bt > Bh > A >/= E horizons. All metals except Cd, Hg, and Mn were concentrated in Bt horizons; As, Cu, Cr, Fe, and Al were enriched in Bh horizons, where clay and organic matterhad accumulated. [ABSTRACT FROM AUTHOR]