In 2017 and 2018, a field survey was initiated on Greek olive orchards to investigate the attractiveness of bait spray applications and the impact of cover and bait sprays applied against the olive fruit fly Bactrocera oleae (Diptera: Tephritidae), on the honeybee, Apis mellifera L. and bumblebees Bombus terrestris, by investigating the pesticides’ residual prevalence. Bee colonies were evenly distributed in three sites located on coastal areas of Western Crete and visited almost weekly between July and October. Samples collected, were analyzed using existing or developed-optimized liquid and gas chromatographic methods. In bee samples, concentrations varied from 0.0013 to 2.3 mg/kg for dimethoate, from 0.0013–0.059 mg/kg for its metabolite omethoate, and from 0.0035 to 0.63 mg/kg regarding the pyrethroids, β-cyfluthrin and λ-cyhalothrin. In one bee sample dimethoate concentration exceeded both acute oral and contact median lethal dose (LD₅₀). Residue findings in bees, along with verified olive oil residues corroborated that those insecticides had been applied in the olive orchards and transferred to bees. The possibility of non-target effects of the bait sprays to the bees, as well as the impact of the contaminated olive to the bees are discussed.

A new multiresidue method for the determination of more than 200 pesticides and degradation products with distinct physicochemical properties and 13 polychlorinated biphenyls (PCBs) in water was developed and statistically validated. The method includes solid phase extraction using Oasis HLB cartridges and analysis using liquid chromatography tandem mass spectrometry (LC–MS/MS) and gas chromatography tandem mass spectrometry (GC–MS/MS) for pesticides and GC–MS for PCBs. The method was validated at different concentration levels for pesticides (1, 0.1 and 0.01 μg L⁻¹) and PCBs (0.1 μg L⁻¹) (five replicates) by assessing the following parameters: accuracy, precision, limit of quantification and linearity. Calibration curves were established for all analytes and regression analysis was performed at 95% confidence level. About 4.1% of the analytes had a recovery less than 60%, 5% from 60 to 70%, 84% from 70 to 120% and 6.8% from 120 to 140%. Acrinathrin had the lowest recoveries among all analytes studied both in LC and GC systems. In terms of pesticide class, lowest recoveries were for pyrethrins, aryloxyphenoxypropionic acids, cyclodienes and organochlorines. For PCBs, recovery ranged from 45.4% for deca-substituted PCB-209, to 105% for di-substituted PCB-11. The developed method was applied for the determination of pesticide residues in 73 samples of groundwater intended for irrigation purposes from three regions in Greece: (1) Prefecture of Messinia, Peloponesse; (2) Prefecture of Heraklion, Crete; and (3) Prefecture of Lasithi, Crete, during the period of November 2011 to November 2013. Eleven samples were found positive for pesticide residues, with ethalfluralin being the most frequently detected pesticide.

A three-year study of the spatial and temporal variation of pesticide residues in Viotikos Kifissos basin (VKB), in central Greece, before and after the application of Low-Input Crop Management systems (LCM), was carried out between May 2009 and November 2011. A total of 253 water samples from 34 sampling points (boreholes, rivers, wells, vadose zone) were analysed for the presence of more than 200 pesticides and degradation products, using liquid and gas chromatography coupled to tandem mass spectrometry. Samples were prepared by solid-phase extraction (SPE) using Oasis HLB cartridges. Almost 70% of the samples were found positive for the presence of pesticides in amounts greater than the limit of detection. The most frequently detected pesticide was fluometuron, followed by s-metolachlor, metalaxyl-M, imidacloprid and ethalfluralin. The highest concentration was recorded for fluometuron (322 μg L⁻¹), ethalfluralin (123 μg L⁻¹) and s-Metolachlor (36.4 μg L⁻¹). Results showed a reduction of the pesticides detected and quantified in water samples during 2011 compared to those measured in 2009 and 2010.

“Can systemic insecticides be used in bait spots in order to kill the adult olive fly?” Effort was directed toward providing an answer to that question. Both field and laboratory tests were implemented to detect the dislodgeable residues of dimethoate, phosmet and b-cyfluthrin in olive leaves and fruit using the LC-MS/MS and GC-MS/MS chromatographic techniques. Residues of dimethoate declined more over time than those of phosmet, while levels of beta-cyfluthrin remained almost stable, both in leaves and fruit. Additionally, significantly higher and faster toxicity of dimethoate and beta-cyfluthrin (>92%) compared to phosmet (80%) to fly adults was shown, which was reduced significantly after a two-week period. Conversely, 100% mortality of the larval stages within olive flesh was observed at the 2nd day for dimethoate and at the 7th day for phosmet. Although phosmet was not expected to contribute to preventing larval development, its application in bait sprays presented similar toxicity to that of dimethoate. However, no larval toxicity was recorded in beta-cyfluthrin. As a primary conclusion, we recommend the avoidance of the use of systemic insecticides in bait sprays.

Method development and validation for the determination of PAHs and NDL-PCBs in fish and smoked fish products using GC-SQ-MS.