Predicting phosphorus availability from chemically diverse conventional and recycling fertilizers.

Fertilizers produced from heterogeneous, phosphorus-rich biowastes are becoming increasingly relevant. Treatment and processing (combustion, pyrolysis, anaerobic digestion, etc.) increase the diversity of their physico-chemical composition even further. We investigated several approaches to characterize P availability from a set of 13 contrasting fertilizers. We tested them directly using standard fertilizer extractions, as well as a continuous, sink-based P extraction (iron bag) method. We also performed Olsen, CAL and diffusive gradients in thin films (DGT) tests on fertilized soil. Standard extractions correlated only weakly, whereas the iron bag method correlated highly (0.73

Heavy metal accumulation in trees growing on contaminated sites in Central Europe.

Metal-accumulating woody species have been considered for phytoextraction of metal-contaminated sites. We investigated Zn and Cd accumulation in tissues of adult trees and associated herbaceous species collected from contaminated areas in Central Europe. We found considerable Cd and Zn accumulation in various willow, poplar and birch species with up to 116mgCdkg(-1) and 4680mgZnkg(-1) in leaves of Salix caprea. Annual variation of Cd and Zn concentrations in leaves of Salix caprea were small, indicating that data obtained in different years can be compared. Metal concentrations in leaves were not related to total (aqua regia) or labile (1M NH(4)NO(3) extract) concentrations in soil but the accumulation factors (leaf concentration: soil concentration) for Cd and Zn followed an inverse log type function. Metal partitioning between tissues showed a minimum in the wood, with increasing concentrations of Cd and Zn towards the leaves and fine roots.

Rhizosphere characteristics of indigenously growing nickel hyperaccumulator and excluder plants on serpentine soil.

The role of rhizosphere processes in metal hyperaccumulation is largely unexplored and a matter of debate, related field data are virtually not available. We conducted a field survey of rhizosphere characteristics beneath the Ni hyperaccumulator Thlaspi goesingense Hálácsy and the metal-excluder species Silene vulgaris L. and Rumex acetosella L. growing natively on the same serpentine site. Relative to bulk soil and to the rhizosphere of the excluder species, we found significantly increased DOC and Ni concentrations in water extracts of T. goesingense rhizosphere, whereas exchangeable Ni was depleted due to excessive uptake of Ni. Chemical speciation analysis using the MINTEQA2 software package revealed that enhanced Ni solubility in Thlaspi rhizosphere is driven by the formation of Ni-organic complexes. Moreover, ligand-induced dissolution of Ni-bearing minerals is likely to contribute to enhanced Ni solubility. Increased Mg and Ca concentrations and pH in Thlaspi rhizosphere are consistent with ligand-induced dissolution of orthosilicates such as forsterite (Mg(2)SiO(4). Our field data reinforce the hypothesis that exudation of organic ligands may contribute to enhanced solubility and replenishment of metals in the rhizosphere of hyperaccumulating species.

Simultaneous multi-element analysis of trace elements in soil samples by means of high-resolution inductively coupled plasma sector field mass spectrometry (SF-ICP-MS).

The potential of SF-ICP-MS for trace element analysis in complex environmental matrices such as soil solutions was investigated. Spectral interferences found in mass spectra of soil matrices are presented in detail. Furthermore, the influences of single components of the soil matrix on the signal intensity of selected elements were studied. Detection limits of different elements are presented with respect to the composition of the matrix. A fast and accurate method for quasi-simultaneous determination of Al, Si, P, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Sr, Mo, Cd, Sn, Hg and Pb in aqueous soil extracts was established.

The Role of Metal Transport and Tolerance in Nickel Hyperaccumulation by Thlaspi goesingense Halacsy.

Metal hyperaccumulators are plants that are capable of extracting metals from the soil and accumulating them to extraordinary concentrations in aboveground tissues (greater than 0.1% dry biomass Ni or Co or greater than 1% dry biomass Zn or Mn). Approximately 400 hyperaccumulator species have been identified, according to the analysis of field-collected specimens. Metal hyperaccumulators are interesting model organisms to study for the development of a phytoremediation technology, the use of plants to remove pollutant metals from soils. However, little is known about the molecular, biochemical, and physiological processes that result in the hyperaccumulator phenotype. We investigated the role of Ni tolerance and transport in Ni hyperaccumulation by Thlaspi goesingense, using plant biomass production, evapotranspiration, and protoplast viability assays, and by following short- and long-term uptake of Ni into roots and shoots. As long as both species (T. goesingense and Thlaspi arvense) were unaffected by Ni toxicity, the rates of Ni translocation from roots to shoots were the same in both the hyper- and nonaccumulator species. Our data suggest that Ni tolerance is sufficient to explain the Ni hyperaccumulator phenotype observed in hydroponically cultured T. goesingense when compared with the Ni-sensitive nonhyperaccumulator T. arvense.

Improved radiotherapy dose calculations using ultrasound uterine localization.

An easy noninvasive method of accurate uterine measurement using B-mode ultrasound for subsequent intracavitary dosimetry is presented. Importance of documentation of uterine size is stressed. This method if universally adopted would help to standardize intracavitary dosimetry and thereapy results could be more meaningfully analyzed.