Residues, dissipation and risk evaluation of spiroxamine in open-field-grown strawberries using liquid chromatography tandem mass spectrometry.

The dissipation dynamic and residues of spiroxamine in open-field-grown strawberries were determined using liquid chromatography tandem mass spectrometry (LC-MS/MS). Spiroxamine application was performed according to Egyptian good agricultural practices recommendation. A QuEChERS-based extraction method along with direct analysis with an LC-MS/MS analytical method were optimized and validated, and the specificity of the techniques used was considered satisfactory. Good linearity (R2 > 0.999) was obtained for spiroxamine within the range of 0.001-0.1 µg/ml. The mean recoveries varied between 97.1 and 108.2%, with inter- and intra-day precision (RSD) <4.9%. The limit of quantitation for spiroxamine was 0.001 mg/kg. The results indicated that spiroxamine degradation in strawberry followed first-order kinetics (R2 > 0.9929) with an estimated half-life value of 4.71 days. Considering the Australian maximum residue limit (0.05 mg/kg) in strawberry and based on the results from residue trials with a preharvest interval of 14 days for strawberry, compliance can be expected. The present results could provide guidance to fully evaluate the risks of spiroxamine residues, preventing any potential health risk to consumers.

Assessment of Pesticide Residues in Human Blood and Effects of Occupational Exposure on Hematological and Hormonal Qualities.

Pesticides are the first choice by farmers for use against plant pathogens, nevertheless their adverse effects to the environment. Current study was designed to measure pesticides residues in blood of spray farmers and to assess their possible effects. Blood indices and thyroid and reproductive hormones were evaluated in blood of adult male volunteers (20-48 years old). Volunteers were divided to three groups; spray-workers (directly-exposed), farmers who live in the country area (indirectly-exposed) and city inhabitants (not exposed). Spray workers had significantly decreased platelet number (PLT, 33%), ratio of large platelet (P-LCR%, 42%), average platelet volume (MPV, 70%), relative width of the distribution of erythrocytes (PDW, 56%), relative content of monocytes, basophils and eosinophils (MXD, 100%) compared to control group. In addition, blood samples of the exposed group showed significantly decreased PLT (30%), P-LCR (40%), MPV (65%) and PDW (50%) compared to the farmers. Furthermore, levels of testosterone, triiodothyronine and thyroxine hormones of spray workers were significantly low compared with the country residents. Then results were further subjected to canonical discriminant analysis to visualize the interrelationships among variables. Results highlighted the critical need for enforced official interventions that reduce overexposure of spray workers throughout Egypt.

Dissipation dynamic, residue distribution and processing factor of hexythiazox in strawberry fruits under open field condition.

Two independent field trials were performed to investigate the dissipation and residue levels of hexythiazox in strawberry. The study presents a method validation for extraction and quantitative analysis of hexythiazox residues in strawberry using HPLC-DAD. The results shown that the mean recoveries ranged from 85% to 93%, furthermore the intra- and inter-day relative standard deviations were less than 10%. The results suggest that the hexythiazox dissipation curves followed the first-order kinetic and its half-life ranged from 3.43 to 3.81 days. The final residues in strawberry were below the Codex maximum residue limit (MRL) (6 mg/kg) after three days of the application. The effects of household processing and storage on the levels of hexythiazox residues were quantified, and it's useful for reducing the dietary exposure. The processing factor after each stage were generally less than 1, indicating that the whole process can reduce the residues of hexythiazox in strawberry. The results could provide guidance to safe and reasonable use of hexythiazox in agriculture.

Residues of organochlorine and synthetic pyrethroid pesticides in honey, an indicator of ambient environment, a pilot study.

Samples of honey were screened to monitor residues of organochlorine and pyrethroid pesticides. The study meant to examine the quality of honey, and to use honey as a bioindicator of environmental contamination. Residue levels were determined by gas chromatography (GC-µECD). Samples had a wide spectrum of organochlorine and synthetic pyrethroids pesticides, with hexachlorobenzene (HCB) as the most frequently detected organochlorine, followed by permethrin, heptachlor epoxide. Only one sample had a concentration of γ-HCH higher than maximum residue limit of honey (0.01 mg kg(-1)). Residues of organochlorines detected, indicate the presence of some fresh supplies, despite the ban imposed on their use. The study confirmed that honey bee and beehive matrices could be used as gauge for monitoring environment contamination. From public health point of view, the observed levels of pesticide residues in honey do not pose a serious health risk to the consumers, but raises questions of the source of organochlorines.