Wspólnotowy Serwis Informacyjny Badan i Rozwoju - CORDIS

Development of analytical and sampling methods for priority pesticides and relevant transformation products in aquifers

The research programme allowed the development of practical sampling and analytical procedures for investigating the contamination of priority herbicides and their transformation products (TP) in the aquifer materials. In particular, different sampling techniques were used by the partners according to the geopedological settings: alluvial material, chalk aquifer, weathered granite material, detritical quaternary material, volcanic material. With regard to sampling techniques, it was found that laboratory suction cup sorption studies demonstrated that ceramic cups of lysimeters adsorbed glyphosate and do not allow the recovery of the pesticide in water samples.

Proper procedures were developed for the analysis of atrazine, terbutilazine, simazine, alachlor, metolachlor, isoproturon, glyphosate, metribuzin and their main TPs in soil and water samples. The different techniques make use of gas chromatography (GC-NPD), gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS) instruments. The results obtained with traditional techniques were then compared to those obtained with enzyme linked immunosorbent assay (ELISA) kits. Millipore kits were used for the determination of atrazine and alachlor residues; Ohmicron ones for the analysis of alachlor, atrazine and metolachlor; Guildhay ones for atrazine and isoproturon quantification. The ELISA-GC/LC comparison gave positive responses in the case of water extracts but for soil samples the presence of matrix interferences was evidentiated.

Some soil saturation experiments were undertaken in order to quantify the possibility of release of herbicides and of their TPs from superficial agricultural soil to groundwater. According to the different compounds, the percentage release in water of the total amount of herbicides contained in soil varied from 2% to 6%.

Transport model calibration was carried out with automatic parameters which involved a conservative compound (bromide) and a non conservative compound (glyphosate). With reference to the mass transport model developed for bromide, the most important aspect is the successful sampling plan developed; it clearly showed the movement of the compound through the soil. It is also relevant that bromide was a suitable tracer to identify basic properties of the medium such as porosity and dispersivity. Glyphosate simulation was the last step of the modelling exercise, after medium characterization by modelling water flow and non reactive solute transport. The model showed realistic results for glyphosate sampling in the surficial part of soil, although uncertainties related to sampling survey distribution, early intensive rain and preferential flow still remain.

Kontakt

Licia GUZZELLA, (Researcher)
Tel.: +39-39-2004304
Faks: +39-39-2004692
Adres e-mail
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