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.

Occurrence and distribution of trifluralin, ethalfluralin, and pendimethalin in soils used for long-term intensive cotton cultivation in central Greece.

In the present study, a soil monitoring program was undertaken in Greek cotton cultivated areas in 2012. Twenty-seven soil samples were collected from the entire Thessaly plain in early summer of 2012, corresponding to approximately three months (current use of pendimethalin), up to one year (for the banned ethalfluralin), and three years (for the also banned trifluralin), after the last dinitroaniline application. Low but not negligible levels of dinitroanilines were detected, ranging from 0.01 to 0.21 µg g-1 d.w. for trifluralin and 0.01-0.048 µg g-1 d.w. for pendimethalin, respectively. Trifluralin was the herbicide most frequently detected (44.4%). The high historic application of trifluralin and its high persistence and accumulation potential is in line with the abundance of the detected residues. The present data indicate that soil samples contain extractable residues of banned trifluralin, but based on the comparison of the theoretical PECplateau for trifluralin (0.277 µg g-1) and the maximum Measured Environmental Concentration, it was concluded that the detected residues should be attributed to previous years' application. The latter suggested the need for continual monitoring of the dinitroaniline family of pesticides, including the banned substances, aiming thus to an improved environmental profile for agricultural areas.

Experiments on Pilot-Scale Constructed Floating Wetlands Efficiency in Removing Agrochemicals.

The efficiency of constructed floating wetlands (CFWs) in their ability to remove agrochemicals (nutrients and pesticides) is here investigated in a series of pilot-scale systems. Four experimental CFWs were designed and constructed; three of them were planted with the aquatic plant species Lemna minor, Azolla pinnata and Eichhornia crassipes. The fourth did not contain any plants and was used as the control. The aim of the study was to evaluate the efficiency of CFW containing aquatic macrophytes in the reduction of pesticides and nutrients, under field conditions. The CFWs operated continuously from May 2021 to September 2021, and their removal efficiencies of nitrogen and phosphorus ions, and five commonly used pesticides were examined. The CFW systems were fed daily with agricultural wastewater which was prepared by mixing a fertilizer and predetermined doses of pesticides. The hydraulic residence time was kept at 14 days. Samples were collected on a weekly basis from both the influent and the effluent of each experimental tank, and were subsequently analyzed in the laboratory. HPLC-DAD and Ion Chromatography were implemented for sample analysis following a very simple sample preparation. Reductions for nutrient ranged from no reduction to 100% removal, whereas for pesticides these varied from no reduction to 98.8% removal, indicating that these systems can be used as efficient and low-cost pollution control technologies for agrochemical wastewater treatment. Significant reduction for certain pesticides was also observed in the algae control tank, thus, proving the efficiency of algae in organic pollution reduction, and recognizing the limitations of aquatic plant use in decontamination.

Investigation of the presence of glyphosate and its major metabolite AMPA in Greek soils.

Glyphosate is a broad-spectrum, non-selective, post-emergence herbicide that controls weeds by inhibiting their ability to synthesize amino acids. It is characterized by high persistence and adsorption to soil, with its dissipation to be highly correlated to the climatic conditions. After its degradation in soil, aminomethylphosphonic acid (AMPA) is the sole and major metabolite produced, characterized also by high persistence and adsorption. Both substances have the potential to remain in soil rather than move to other environmental compartments. Considering the recent intense debate during the EU renewal of glyphosate along with its wide use, it is apparent that both glyphosate and AMPA require further attention and information on their occurrence and distribution in EU soils. The present study does constitute the first extended soil monitoring survey of glyphosate and AMPA with samples derived during the years 2013-2015, from the highest extent of the Greek territory. Specific attention was given to areas of high agricultural production as well as to urban areas, since glyphosate-containing products are also registered for non-professional uses. The positive samples represented the 36.7% for glyphosate and 44.9% for AMPA, while the detected residues fluctuated from 0.026 to 40.6 µg g-1 and from 0.01 to 2.5 µg g-1 for glyphosate and AMPA, respectively. Our findings can constitute a basis for the determination of the background concentration levels of glyphosate and its metabolite in the Greek territory. As such, apart from being the first study for glyphosate monitoring in Greece, the most significant highlights recognized in the present work are the following:The high levels of glyphosate and AMPA residues in urban areas that indicate possible misuse of pesticidesThe generally low detection in the main agricultural basins and particularly near water recipientsThe fact that a potential for misuse of herbicides cannot be excluded even in the case of agricultural areas (considering that the maximum detection was in an olive grove and exceeded the model-predicted concentrations by 13 times).

Pesticide residue concentration in soil following conventional and Low-Input Crop Management in a Mediterranean agro-ecosystem, in Central Greece.

The present study was focused on the comparative evaluation of pesticide residues, determined in soil samples from Kopaida region, Greece before and after the implementation of Low-Input Crop Management (LCM) protocols. LCM has been suggested as an environmental friendly plant protection approach to be applied on crops growing in vulnerable to pollution ecosystems, with special focus on the site specific problems. In the case of the specific pilot area, the vulnerability was mainly related to the pollution of water bodies from agrochemicals attributed to diffuse pollution primarily from herbicides and secondarily from insecticides. A total of sixty-six soil samples, were collected and analyzed during a three-year monitoring study and the results of the determined pesticide residues were considered for the impact evaluation of applied plant protection methodology. The LCM was developed and applied in the main crops growing in the pilot area i.e. cotton, maize and industrial tomato. Herbicides active ingredients such as ethalfluralin, trifluralin, pendimethalin, S-metolachlor and fluometuron were detected in most samples at various concentrations. Ethalfluralin, which was the active ingredient present in the majority of the samples ranged from 0.01 µg g(-1) to 0.26 µg g(-1) soil dry weight. However, the amount of herbicides measured after the implementation of LCM for two cropping periods, was reduced by more than 75% in all cases. The method of analysis was based on the simultaneous extraction of the target compounds by mechanical shaking, followed by liquid chromatography mass spectrometric and gas chromatography electron capture (LC-MS/MS and GC-ECD) analysis.