Dissipation kinetics and exposure of spirotetramat and pymetrozine in open fields, a prelude to risk assessment of green bean consumption.

Determination and dissipation kinetics of pymetrozine and spirotetramat in green bean were studied using a QuEChERS method coupled to high-performance liquid chromatography-tandem mass spectrometry. Pymetrozine recoveries ranged between 88.4-93.7%, with relative standard deviation (RSD) of 5.5-14.4%. For spirotetramat the recoveries ranged between 91.7-103.4%, and the RSD were in the range of 3.2 to 12.4%. The limits of quantification (LOQs) were 0.01 mg/kg and 0.005 mg/kg for pymetrozine and spirotetramat, respectively.The developed analytical method was used to study the degradation rates of pymetrozine and spirotetramat in green bean grown in open field. Results showed that pymetrozine and spirotetramat followed the first-order kinetics model with half-lives of 3.3 days and 4.2 days, respectively. Furthermore, risk assessment was carried out which showed that, the chronic risk quotient (RQc) values for pymetrozine and spirotetramat were much lower than 100%. The present results indicated that the health risks posed for consumers by the pymetrozine and spirotetramat residues were negligible at the recommended dosages.

Dissipation behavior of thiophanate-methyl in strawberry under open field condition in Egypt and consumer risk assessment.

Thiophanate methyl is a broad-spectrum benzimidazole fungicide extensively applied in pre- and post-harvest, for the control of a wide range of fruit and vegetable pathogens. In the current work, the residue behavior of thiophanate methyl after application on strawberries and an estimation of the consumer dietary exposure was performed. Supervised field trials were conducted in Egypt (Qaluobiya Governorate) as to investigate the residue dynamics and terminal residues at different PHIs of thiophanate methyl and its metabolite carbendazim in strawberries under Egyptian conditions. For the measurement of residues in fruits, a QuEChERS-based protocol coupled with LC-MS/MS was optimized and successfully validated at 0.01 mg kg-1. The half-life (t1/2) of thiophanate methyl in strawberries was estimated, and a dietary risk assessment was performed employing both FAO/WHO and EFSA approaches.

Consumer safety evaluation of pyraclostrobin residues in strawberry using liquid chromatography tandem mass spectrometry (LC-MS/MS): An Egyptian profile.

The dissipation rates of pyraclostrobin, a methoxyacrylate strobilurin group fungicide, along with its final residues and dietary exposure in strawberry were studied under Egyptian field conditions. Extraction was performed using a QuEChERS method, while residue determination was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS) with limits of quantitation of 0.001 mgkg-1. At three different fortification levels (1.0, 10 and 100 ng/g) of pyraclostrobin applied to untreated strawberry samples, the recoveries ranged between 97 and 104% with relative standard deviation (RSD) of 1-6% (n = 6). The reported analytical method fulfills the standard requirements with regard to specificity, repeatability, limit of quantitation and recoveries. The half-life (t1/2) of pyraclostrobin after one single application of the recommended rate was 5 days. Risk assessment study was carried out by comparing the national estimated daily intake (NEDI) against acceptable daily intake (ADI) under good agricultural practice (GAP) conditions. Results indicated that strawberry treated with pyraclostrobin at the recommended dosage, are safe for human consumption three days after two successive applications with 14 days interval between each application. The present research should pave the way for the establishment of the safe and proper use of pyraclostrobin in strawberry in Egypt.

Risk assessment of some organic contaminants: a case study based on food consumption in Tanta and Ismailia cities, Egypt.

The impact of some organic pollutants on some residents of Tanta and Ismailia cities of Egypt through their consumption of vegetables, fruits and fish (Nile tilapia and catfish) was examined. Residues of organochlorine (OCS) and organophosphorus (OPS) as some polychlorinated biphenyls (PCBS) were compared with pesticides as well maximum residue limits (MRLS). Probable health risk to consumers was also assessed. P, P'-DDT, P, P'-DDE, P, P'-DDD, endrin, α-BHC, (lindane), and hexachlorbenzene (HCB) were the most detected organochlorine compounds, but did not exceed MRLs.However, OPS residues were the most frequently detected contaminants. PCBs congeners 28, 70, 52, and 180 were detected in tilapia fish from Tanta, but congeners 28 and 180 were the only detected congeners in samples collected from Ismailia region. ∑PCBS values in all matrices did not exceed MRLS. Hazard index (HI) exhibited unity for all compounds at 50 the decreasing order: catfish > vegetables > fruits > Nile tilapia in Tanta, while in Ismailia the order was Nile tilapia > fruit > vegetables. Results also revealed that risk values for adults were greater than those of children categories.

Hazard index, a tool for a long term risk assessment of pesticide residues in some commodities, a pilot study.

Samples of some vegetables were analyzed for pesticides residues using the accredited (QuEChERS) method. The method allowed the determination of 215 compounds of different pesticide chemical groups. LC-MS/MS and GC-MS/MS were used for residues quantification. In a total number of 116 samples, no pesticides residues were detected in 34 samples (29.3%), while 82 samples (70.7%) had detectable pesticide residues, with some samples exceeding the MRLs levels established by the Codex Alimentarius Commission. The hazard index (HI %), representing the long--term risk assessment was in the range of 0.01%-15.04% of the ADI's. The highest exposure was observed for ethion, followed by chlorpyifos, both of them are organophosphates, at 15.04% and 2.45% of ADI respectively. The acute (short-term) exposure was also estimated. Results showed a potential risk for children posed by 3 pesticides, meanwhile, residues of one pesticides showed potential risk to adults (>100% of ARfD). The present work is an attempt to provide a model for the use of WHO template for calculating the short term intake. This model is especially useful for developing countries where information about consumption rate is rather meager.

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.

Residue levels of DDE and PCBs in the blood serum of women in the Port Said region of Egypt.

An investigation was conducted to detect residues of 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE) and polychlorinated biphenyls (PCBs) in blood serum samples collected from a cohort of fasting females attending the health insurance outpatient clinic at Port Said between July 1999 and July 2000. Females involved in the study included 43 females diagnosed with invasive adenocarcinoma of the breast, 21 female suffering benign breast disease, and 11 normal healthy females. Serum was separated and its contents of DDE and PCBs were extracted and determined, using gas chromatography, equipped with electron capture detector. Mean residues of DDE detected in the three examined groups of females were 41+/-5.2, 48+/-6.2 and 31+/-2.5ng/g for breast cancer cases, benign breast disease cases and controls, respectively, indicating some significantly less residues in blood serum of control females. While PCBs residues detected were 54+/-17, 59+/-23 and 61+/-21ng/g, for the three groups, respectively. Residues of DDE detected in all females alike in the present study are about 15 times higher than residues detected in Canada and The Netherlands.