Monitoring of glyphosate and AMPA in soil samples from two olive cultivation areas in Greece: aspects related to spray operators activities.

The persistence of glyphosate and its primary metabolite AMPA (aminomethylphosphonic acid) was monitored in two areas in Southern Greece (Peza, Crete and Chora Trifilias, Peloponnese) with a known history of glyphosate use, and the levels of residues were linked to spray operators' activities in the respective areas. A total of 170 samples were collected and analysed from both areas during a 3-year monitoring study. A new method (Impact Assessment Procedure - IAP) designed to assess potential impacts to the environment caused by growers' activities, was utilised in the explanation of the results. The level of residues was compared to the predicted environmental concentrations in soil. The ratio of the measured concentrations to the predicted environmental concentrations (MCs/PECs) was > 1 in Chora the first 2 years of sampling and < 1 in the third year, whilst the MCs/PECs ratio was < 1 in Peza, throughout the whole monitoring period. The compliance to the instructions for best handling practices, which operators received during the monitoring period, was reflected in the amount of residues and the MCs/PECs ratio in the second and especially the third sampling year. Differences in the level of residues between areas as well as sampling sites of the same area were identified. AMPA persisted longer than the parent compound glyphosate in both areas.