Spatial distribution of jet fuel in the vadoze zone of a heterogeneous and fractured soil.

The goal of the present work is to screen and evaluate all available data before selecting and testing remediation technologies on heterogeneous soils polluted by jet fuel. The migration pathways of non-aqueous phase liquids (NAPLs) in the subsurface relate closely with soil properties. A case study is performed on the vadoze zone of a military airport of north-west Poland contaminated by jet fuel. Soil samples are collected from various depths of two cells, and on-site and off-site chemical analyses of hydrocarbons are conducted by using Pollut Eval apparatus and GC-MS, respectively. The geological conceptual model of the site along with microscopic and hydraulic properties of the porous matrix and fractures enable us to interpret the non-uniform spatial distribution of jet fuel constituents. The total concentration of the jet fuel and its main hydrocarbon families (n-paraffins, major aromatics) over the two cells is governed by the slow preferential flow of NAPL through the porous matrix, the rapid NAPL convective flow through vertical desiccation and sub-horizontal glaciotectonic fractures, and n-paraffin biodegradation in upper layers where the rates of oxygen transfer is not limited by complexities of the pore structure. The information collected is valuable for the selection, implementation and evaluation of two in situ remediation methods.

Efficiency of defined strains and of soil consortia in the biodegradation of polycyclic aromatic hydrocarbon (PAH) mixtures.

The microbiological characteristics of the bacterial degradation of mixtures of five polycyclic aromatic hydrocarbons (PAH), phenanthrene, fluorene, anthracene, fluoranthene and pyrene, were investigated. Three pure bacterial strains using one or several of these PAH as carbon sources were selected. The interactions between PAH during the degradation of PAH pairs by each of these strains were studied and their effects on the kinetics and the balance of degradation were characterised. Competition between PAH and degradation by cometabolism were frequently observed. Mixed cultures of two or three strains, although possessing the global capacity to mineralise the set of five PAH, achieved limited degradation of the mixture. In contrast, a consortium from a PAH-contaminated soil readily mineralised the five-PAH mixture. The results suggested that soil consortia possessed a wider variety of strains capable to compensate for the competitive inhibition between PAH as well as specialised strains that mineralised potentially inhibitory PAH metabolites produced by cometabolism.

[Gonadotropin-releasing hormone receptors in human breast cancer tissue]. / GnRH-Rezeptoren im menschlichen Mamma-karzinomgewebe.

Analogues of gonadotropin-releasing hormone (GnRH) are presently being investigated for the treatment of metastatic breast cancer. Although their effects are thought to be mediated via the suppression of gonadotropins and gonadal steroids, they could possibly also act directly on the tumour. The binding of a GnRH-agonist to membrane fractions of 97 primary human breast carcinomas was investigated. In 43 cases (44%) the presence of specific GnRH receptor binding sites (above 3 fmol/mg membrane protein) was shown. GnRH receptor content was 6.2 fmol/mg membrane protein in estradiol receptor (ER) positive tissues and in ER negative tissues 2.0 fmol/mg membrane protein (p less than 0.05). Progesterone receptor (PR) positive contained 5.2 fmol/mg protein and PR negative carcinoma contained 2.0 fmol/mg membrane protein. In postmenopausal women GnRH receptor concentration was 5.4 and 2.9 fmol/mg membrane protein, respectively, in ER positive and negative tissues (p less than 0.05) whereas 4.4 and 5.2 fmol/mg membrane protein, respectively, in PR positive and negative samples. Binding of GnRH was positive (above 3 fmol/mg protein) in 33% premenopausal and in 54% of postmenopausal cases. Further clinical studies with GnRH analogues will clarify the therapeutic value of GnRH receptor determination in breast cancer.