The effects of washing with tap and ozone water, ultrasonic cleaning and boiling on 16 pesticide (ten fungicides and six insecticides) residue levels in raw strawberries were investigated at different processing times (1, 2 and 5 min). An analysis of these pesticides was conducted using gas chromatography with nitrogen-phosphorous and electron capture detection (GC-NPD/ECD). The processing factor (PF) for each pesticide in each processing technique was determined. Washing with ozonated water was demonstrated to be more effective (reduction from 36.1 to 75.1 %) than washing with tap water (reduction from 19.8 to 68.1 %). Boiling decreased the residues of the most compounds, with reductions ranging from 42.8 to 92.9 %. Ultrasonic cleaning lowered residues for all analysed pesticides with removal of up to 91.2 %. The data indicated that ultrasonic cleaning and boiling were the most effective treatments for the reduction of 16 pesticide residues in raw strawberries, resulting in a lower health risk exposure. Calculated PFs for alpha-cypermethrin were used to perform an acute risk assessment of dietary exposure. To investigate the relationship between the levels of 16 pesticides in strawberry samples and their physicochemical properties, a principal component analysis (PCA) was performed.Graphical abstractᅟ

Greenhouse studies were conducted to evaluate the dissipation rate kinetics and estimate the behavior of selected pesticides after washing, peeling, simmering, and canning of tomato expressed as processing factor (PF). Two varieties (Marissa and Harzfeuer) were treated by six fungicides: azoxystrobin, boscalid, chlorothalonil, cyprodinil, fludioxonil, and pyraclostrobin at single and double dose and risk assessment defined as hazard quotient was performed. The QuEChERS method was used for sample preparation followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The dissipation of fungicides approximately fitted to a first-order kinetic model, with half-life values ranging from 2.49 and 2.67 days (cyprodinil) to 5.00 and 5.32 days (chlorothalonil) for Marissa and Harzfeuer variety, respectively. Results from processing studies showed that treatments have significant effects on the removal of the studied fungicides for both varieties. The PFs were generally less than 1 (between 0.01 and 0.90) and did not depend on variety. The dietary exposure assessed based on initial deposits of application at single and double dose on tomatoes and concentration after each process with PF correction showed no concern to consumer health. Our results would be a useful tool for monitoring of fungicides in tomatoes and provide more understanding of residue behavior and risk posed by these fungicides.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-016-6260-x) contains supplementary material, which is available to authorized users.

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In the present study an effort has been made to evaluate the residues of insecticides, fungicides and herbicides in fruit fromPolandand their health risks assessed. Accredited multiresidue methods based on gas and liquid chromatography, and spectroscopic technique were used to determine the concentrations above 160 pesticides. A total of 392 samples of 15 different fruit were collected during the May 2010 to October 2012. In 48.2% of samples no residues were found, 45.9% of samples contained pesticide residues at or below the EU MRL, and 5.9% of samples contained pesticide residues above MRL. Sour cherries (66%) and apples (63%) were the commodities in which pesticide residues the most frequently occurred. Thirty one different pesticides were detected in total. Dithiocarbamate, captan, cyprodinil and boscalid were the pesticide most frequently found. Multiple pesticides ( > 1 pesticide) were detected in about 30.1% samples. The dietary intake of residues of some pesticides can pose acute hazards. Data obtained were used for estimating the potential health risks associated with the exposures to these pesticides. The highest estimated daily intakes (EDIs) for children were: 22% for dimethoate and 112% for diazinone of the ADI. The most critical commodity was apple, contributing 1.30 to the acute Hazard Index for flusilazole. The results show that despite a high occurrence of pesticide residues in fruit it could not be considered a serious public health problem. Nevertheless, an investigation into continuous monitoring of pesticide residues in fruit is recommended.

In this study two analytical methods, one based on matrix solid phase dispersion (MSPD) and the other on liquid–solid extraction (LSE), coupled with gas chromatography, were evaluated and used to determine the presence of 163 pesticides (6 acaricides, 62 fungicides, 18 herbicides and 77 insecticides) in various herbs. Both methods were optimized considering different parameters (sample to sorbent mass ratio, extracting solvent, sorbents for clean-up step, etc.). The results of these validated sample preparation procedures were compared. Under optimum conditions, the mean recoveries obtained were in the range of 70–119 % for MSPD for most pesticides and 70–118 % for LSE, but with several exceptions. Precision values, expressed as relative standard deviation (RSD), were ≤16 % for MSPD and <18 % for LSE. Correlation coefficients were higher than 0.99254 for both methods. LODs (limits of detection) and LOQs (limits of quantification) for MSPD were within the ranges of 0.003–0.03 and 0.005–0.04 mg/kg, respectively. The data demonstrate that the MSPD method was successfully used for the analysis of 163 pesticides in the following herbs: chamomile (Matricaria chamomilla L.), linden (Tilia), lungwort (Pulmonaria L.), melissa (Melissa L.), peppermint (Mentha piperita L.) and thyme (Thymus vulgaris L.). This paper indicates the potential of MSPD for qualitative and quantitative analysis of pesticide residues. This method was therefore validated at three spiking levels (the first ranging from 0.005 to 0.05 mg/kg, the second from 0.05 to 0.5 mg/kg and the third from 0.25 to 2.5 mg/kg) and applied to real samples (n = 15). MSPD proves to be a simple, fast and very useful multiresidue method and can be recommended for routine pesticide monitoring studies in various herbs.

The analytical tool for analysis of pesticide residues in honey must still be improved. Therefore, a sensitive, selective, rapid, and reliable analytical method for the analysis of pesticide residue belonging to 29 different classes at very low concentration levels was developed. Over 130 insecticides were extracted from the honey matrix using different amounts of sample, concentrations of the extraction solvent, and cleanup sorbents. Acceptable extraction recoveries accounting for matrix effect were obtained using the cleanup sorbent combination chitosan/aluminum oxide/C8 (200/200/200 mg) and 1% FA in ACN. Determinations were made by liquid chromatography-tandem mass spectrometry (LC-MS/MS). For most compounds, the recoveries range from 70 to 120%, with relative standard deviations < 20%. Linear correlation coefficients (r2) were higher than 0.99 at concentration levels of 0.001-0.100 mg kg−1. A positive matrix effect was observed for up to 95% of organophosphates and 43% of pyrethroids and a negative effect for 37% of neonicotinoids. This work showed that the presented method is convenient and reliable for quick monitoring of insecticides in honey samples.

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The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg−1) and detection (0.0005 mg kg−1) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001–0.5 mg kg−1) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT50 of S-MET calculated according to the first-order kinetics model was 11.1–14.7 days (soil) and 9.6–13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.