Samples (200 mL) were extracted using off-line SPE with polymeric OASIS 60 mg cartridges. Analyses were performed by gas chromatography-mass spectrometry (GC-MS) using selected ion monitoring (SIM) and full scan for quantification and unequivocal identification, respectively. This paper reports the detection limit for the compounds studied (from 0.001 to 0.030 μg L−1), and method performance as regards to linearity (0.01–1.3 μg L−1), reproducibility (less than 9%) and recovery (84 to 95%).

Active endocrine disruptors (nonylphenol, octylphenol and bisphenol A) were analysed in 2 aquifers and the corresponding surface waters. They are compounds widely used in industrial processes. The objective of this study was to determine the leaching potential of these compounds in groundwaters and to eventually correlate these levels with surface water samples. The areas sampled were agricultural, close to large cities and with an important industrial activity in the surrounding area.

The results from a monitoring program revealed the presence of the target compounds in all samples analysed, at levels of 0.07 and 1.9 μg L−1. The presence of these compounds in groundwater was attributed basically to degradation of inert ingredients present in the formulation of many pesticides or to the increasing application of sludge in agricultural practice, although the infiltration of industrial run-off and wastewater disposal cannot be disregarded.

This work was financed by the Spanish Ministerio de Ciencia y Tecnología (PPQ2001-1805-C03-01).

6 pages, 5 figures, 2 tables.-- Available online Oct 12, 2006.

Peer reviewed