The sequential extraction procedures described by Tessier et al., McGrath and Cegarra, and Gimeno-García et al. were compared to investigate trace element (As, Cr, Cu, Pb, and Zn) partitioning patterns and extraction efficiency in three contaminated soils from Mediterranean regions of Spain. Soils were selected from Onda (Castellón) (S1), Aznalcóllar (Sevilla) (S2), and Silla (Valencia) (S3). S1 was a soil contaminated with Pb and Zn after dumping of wastes from the manufacture of ceramic tiles, S2 was polluted accidentally with a highly acid and As-concentrated sludge from mining activities, and S3 was a soil with a high Cr content from tannery sludge disposal. Trace element distribution in the soils--soluble, exchangeable, organically bound, precipitated with carbonates, bound to iron and manganese oxides, and precipitated with sulfides fractions--varied significantly according to the extraction procedure used. In addition, different extraction efficiencies were found for the three sequential extraction procedures compared. Finally, the trace elements studied showed different and specific distribution patterns between the various soil fractions examined.

Vitellogenin (VTG) is a protein produced in the liver of oviparous animals in response to oestrogens. Abnormal production of VTG by males, therefore, is used as a biological indicator of exposure to xeno-oestrogens. In this study, a sandwich-ELISA for measuring VTG in Liza aurata (golden grey mullet) was developed and validated. Plasma VTG was purified from 17beta-oestradiol-injected immature individuals of mullet, by size-exclusion and ion-exchange chromatography. Polyclonal antibodies against VTG were raised in rabbits. A sensitive immunoassay was developed for measurement of vitellogenin in L. aurata serum, reaching a quantification limit of 0.01 microg mL(-1) and a dynamic range from 0.02 to 2 microg mL(-1). The assay is specific, because high levels (>100 microg mL(-1)) of carp (Cyprinus carpio), goldfish (Carassius auratus), tilapia (Oreochromis niloticus), tench (Tinca tinca), rainbow trout (Oncorhynchus mykiss), European eel (Anguilla anguilla) and frog (Rana perezi) purified VTG, give negligible responses. The assay was used to analyse plasma samples from wild mullet.