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The possible involvement of the epiphytic yeasts Rhodotorula glutinis and Rhodotorula rubra in the biodegradation of the insecticide chlorpyrifos and its metabolite 3,5,6-trichloro-2-pyridinol (TCP), in pure cultures and in plant surfaces (tomato fruits) was investigated. Higher biodegradation rates were observed as the concentration of chlorpyrifos and the inoculum of the microorganisms were increased, while the yeasts proved to be more active at 25 and 15 °C. The presence of glucose in the mineral nutrient medium, as an extra source of carbon, delayed the biodegradation by Rhodotorula glutinis, while Rhodotorula rubra proved to be more active. The detection and quantification of the parent compound and TCP was successfully achieved using a LC/MS/MS chromatographic system. The in vitro enzymatic assays applied suggested that esterases may be involved in the biodegradation of chlorpyrifos, a fact that was further enhanced after the addition of the synergists triphenyl phosphate, diethyl maleate and piperonyl butoxide in the biodegradation trials. The decrease of chlorpyrifos residues on tomato fruits confirmed the corresponding on pure cultures, resulting in the suggestion that the yeasts R. glutinis and R. rubra can possibly be used successfully for the removal or detoxification of chlorpyrifos residues on tomatoes.

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A 1-year monitoring study is presented on the chemical status of two surface water reservoirs in a decentralized Mediterranean island. Water samples were collected at varying depths in the two surface water reservoirs and different seasons between November 2015 and September 2016, covering both wet and dry periods of the year. Samples were analyzed in order to determine major chemical parameters and priority substances based on the EU Water Framework Directive (2000/60/EC) and the latest revision of the Priority Substances Policy Directive (2013/39/EU). Tested parameters in both reservoirs did not exceed the set limits. Increased pollutant concentrations were observed in the bottom samples. More than 200 pesticide active substances were determined but none of them was above the parametric trigger value (0.1 µg L-1). Toxic metals were not detected in the examined water samples, whereas the relatively high concentrations of Mn and Cu in the bottom samples are mainly attributed to geogenic background concentrations. Based on the results of the present study, it can be concluded that the chemical situation of both water reservoirs is considered acceptable; however, continuous monitoring should be implemented in the area.

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One of the recent trends in Analytical Chemistry is the development of economic, quick and easy hyphenated methods to be used in a field that includes analytes of different classes and physicochemical properties. In this work a multi-residue method was developed for the simultaneous determination of 28 xenobiotics (polar and hydrophilic) using hydrophilic interaction liquid chromatography technique (HILIC) coupled with triple quadrupole mass spectrometry (LC-MS/MS) technology. The scope of the method includes plant growth regulators (chlormequat, daminozide, diquat, maleic hydrazide, mepiquat, paraquat), pesticides (cyromazine, the metabolite of the fungicide propineb PTU (propylenethiourea), amitrole), various multiclass antibiotics (tetracyclines, sulfonamides quinolones, kasugamycin and mycotoxins (aflatoxin B1, B2, fumonisin B1 and ochratoxin A). Isolation of the analytes from the matrix was achieved with a fast and effective technique. The validation of the multi-residue method was performed at the levels: 10 µg/kg and 100 µg/kg in the following representative substrates: fruits-vegetables (apples, apricots, lettuce and onions), cereals and pulses (flour and chickpeas), animal products (milk and meat) and cereal based baby foods. The method was validated taking into consideration EU guidelines and showed acceptable linearity (r ≥ 0.99), accuracy with recoveries between 70 and 120% and precision with RSD ≤ 20% for the majority of the analytes studied. For the analytes that presented accuracy and precision values outside the acceptable limits the method still is able to serve as a semi-quantitative method. The matrix effect, the limits of detection and quantification were also estimated and compared with the current EU MRLs (Maximum Residue Levels) and FAO/WHO MLs (Maximum Levels) or CXLs (Codex Maximum Residue Limits). The combined and expanded uncertainty of the method for each analyte per substrate, was also estimated.

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Mycotoxin contamination is a common problem on feedstuffs, that can be formed on crops in the field, during harvest, storage, processing or feeding. The scope of the current study was to investigate the levels of Aflatoxin B1, Aflatoxin B2, Aflatoxin G1, Aflatoxin G2, Diacetoxyscirpenol, Ochratoxin A, Toxin HT-2, Toxin T-2 and zearalenone in a variety of feedstuffs (maize silage, alfalfa hay, cottonseed cake, corn grain and concentrates) fed to ruminants and the possible contamination of milk though consumption. For this purpose an easy and simple multiresidue LC-MS/MS method without any clean-up step was developed and successfully validated in feed and milk matrices. The LOQ of the method was set at 10 µg/kg for all analytes and 0.05 µg/kg for Aflatoxin M1 and Ochratoxin A in milk. The results showed that 7 cottonseed cake samples, out of 13 were contaminated with Aflatoxin B1 at a level higher than the maximum levels as set by EU Regulations and with Toxin T-2 with values ranging from 8 to 562 µg/kg. Nine maize silages and 6 alfalfa hay samples were contaminated with Aflatoxin G2 at levels higher than the maximum tolerance limit. No mycotoxins or their metabolites were found above the LOQ in any of the analyzed milk samples.

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The objective of this study was to investigate if milk from dairy sheep and goats, fed mainly with supplementary feed during the winter months, was contaminated with pesticides residues. Tauwo hundred milk samples from sheep and goats were collected from 10 farms of each animals. The sheep and goats farms were selected from those which represent common conventional production and feeding systems in Greece. Milk and feed samples (alfalfa hay, wheat straw, shrubs, pasture and concentrates) were taken from each farm to analyze for pesticides residues. The results showed that the summation operatorendosulfan was the main pesticide residue which was detected in all the concentrates samples at a mean concentration of 5.36 mgkg(-1), which is much higher from the maximum residue level (MRL). In addition, the summation operatorendosulfan was also detected in all the alfalfa hay samples but at a mean concentration of 0.10 mgkg(-1) which is lower than the MRL. The mean concentrations of endosulfan alpha and beta were 2.82 and 2.39 mgkg(-1) in the concentrates samples and 0.08 and 0.02 mgkg(-1) respectively in alfalfa hay samples. In the wheat straw, shrubs and pasture samples no pesticides residues were detected. No pesticide residues were also detected in milk samples of sheep and goats. Thus, this milk from the farms sampled presents no human health risks as far as the contaminants analyzed concerned.

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