Mohamed H. El-Saeid

Pesticide Residues in Canned Foods, Fruits, and Vegetables: The Application of Supercritical Fluid Extraction and Chromatographic Techniques in the Analysis

Multiple pesticide residues have been observed in some samples of canned foods, frozen vegetables, and fruit jam, which put the health of the consumers at risk of adverse effects. It is quite apparent that such a state of affairs calls for the need of more accurate, cost-effective, and rapid analytical techniques capable of detecting the minimum concentrations of the multiple pesticide residues. The aims of this paper were first, to determine the effectiveness of the use of Supercritical Fluid Extraction (SFE) and Supercritical Fluid Chromatography (SFC) techniques in the analysis of the levels of pesticide residues in canned foods, vegetables, and fruits; and second, to contribute to the promotion of consumer safety by excluding pesticide residue contamination from markets. Fifteen different types of imported canned and frozen fruits and vegetables samples obtained from the Houston local food markets were investigated. The major types of pesticides tested were pyrethroids, herbicides, fungicides, and carbamates.By using these techniques, the overall data showed 60.82% of the food samples had no detection of any pesticide residues under this investigation. On the other hand, 39.15% different food samples were contaminated by four different pyrethroid residues ± RSD% ranging from 0.03 ± 0.005 to 0.05 ± 0.03 ppm, of which most of the pyrethroid residues were detected in frozen vegetables and strawberry jam. Herbicide residues in test samples ranged from 0.03 ± 0.005 to 0.8 ± 0.01 ppm. Five different fungicides, ranging from 0.05 ± 0.02 to 0.8 ±0.1 ppm, were found in five different frozen vegetable samples. Carbamate residues were not detected in 60% of investigated food samples. It was concluded that SFE and SFC techniques were accurate, reliable, less time consuming, and cost effective in the analysis of imported canned foods, fruits, and vegetables and are recommended for the monitoring of pesticide contaminations.

Multiresidue Analysis of 86 Pesticides Using Gas Chromatography Mass Spectrometry: II-Nonleafy Vegetables

A total of 1057 samples of fresh vegetables from import and domestic production were analyzed (cold pepper, egg plant, carrot, cucumber, potato, hot pepper, cultivation tomato, squash, beans, okra, onions, cauliflower, and green house tomato). The aim of this study was to investigate pesticide residues in market foods in Riyadh, which have been collected from Riyadh Development Company (Al-Tamer Vegetables Market). Pesticide residues were determined by gas chromatography with mass selective detector (GC-MSD). A multiresidue method was developed and described for simultaneous determination of 86 pesticides commonly used in crop protection. This method used to determine 86 pesticide residues with a broad range of physicochemical properties in fresh vegetables related to organophosphorus (OPP), organochlorines (OCP), pyrethroids, and carbamates mainly used in agriculture. Sample extract was cleaned up by using AOAC method. Pesticide residues above the maximum residue limits (MRL) were detected in 15.89% of the total samples (168 from 1057 samples), but 83.90% of the total samples (887 from 1057 samples) has no residues or contained pesticide residues at or below MRL. The detected and most frequently found pesticide residues were permethrin (45 times) and endosulfan (34 times) followed by deltamethrin (27 times). The findings of this study pointed to the following recommendations: the need for a monitoring program for pesticide residues in imported food crops.

Impacts of extraction methods in the rapid determination of atrazine residues in foods using supercritical fluid chromatography and enzyme-linked immunosorbent assay: microwave solvent vs. supercritical fluid extractions.

It is an accepted fact that many food products that we eat today have the possibility of being contaminated by various chemicals used from planting to processing. These chemicals have been shown to cause illnesses for which some concerned government agencies have instituted regulatory mechanisms to minimize the risks and the effects on humans. It is for these concerns that reliable and accurate rapid determination techniques are needed to effect proper regulatory standards for the protection of peoples nutritional health. This paper, therefore, reports the comparative evaluation of the extraction methods in the determination of atrazine (commonly used in agricultural as a herbicide) residues in foods using supercritical fluid chromatography (SFC) and enzyme-linked immunosorbent assay (ELISA) techniques. Supercritical fluid extraction (SFE) and microwave solvent extraction (MSE) methods were used to test samples of frozen vegetables, fruit juice, and jam from local food markets in Houston. Results showed a high recovery percentage of atrazine residues using supercritical fluid coupled with ELISA and SFC than with MSE. Comparatively, however, atrazine was detected 90.9 and 54.5% using SFC and ELISA techniques, respectively. ELISA technique was, however, less time consuming, lower in cost, and more sensitive with low detection limit of atrazine residues than SFC technique.

Evaluation of Groundwater for Arsenic Contamination Using Hydrogeochemical Properties and Multivariate Statistical Methods in Saudi Arabia

The aim of this research is to evaluate arsenic distribution and associated hydrogeochemical parameters in 27 randomly selected boreholes representing aquifers in the Al-Kharj geothermal fields of Saudi Arabia. Arsenic was detected at all sites, with 92.5% of boreholes yielding concentrations above the WHO permissible limit of 10 μg/L. The maximum concentration recorded was 122 μg/L (SD = 29 μg/L skewness = 1.87). The groundwater types were mainly Ca

Silicon Fertilization a Tool to Boost up Drought Tolerance in Wheat (Triticum aestivum L.) Crop for Better Yield

ABSTRACT In this study, impact of silicon (Si) application on wheat performance under drought stress is studied. Experimental soil was sandy clay loam with an average pH of 8.01, electrical conductivity (EC) of 2.36 dSm−1, and calcium carbonate (CaCO3) content of 2.16%. Soil was severely deficient in organic matter (<1%). Average extractable phosphorus (P) and potassium (K) concentration was 230 and 5.21 mg kg−1, respectively. Silicon potassium metasilicate (K2SiO3) was applied at the rate of 0 and 12 kg/ha with three canal water irrigation frequencies including two, three, and four under randomized complete block design (RCBD) factorial fashion with three replications. Results indicated that drought stress significantly reduced plant height, spike length, shoot fresh weight, and number of spikelets/spike, eventually enhancing wheat yield. Concentration of K+ in shoot (28.65 mg g−1) and grains (3.51 mg g−1) increased with Si application, which helped to maintain water potential in plant even under reduced moisture level in plants and soil, ultimately producing more yield and biomass under drought stress conditions.

Evaluation of the Most Current and Effective Methods in the Analysis of Chlorinated Dioxins in Ground Beef

Chlorinated dioxins are the group of environmental pollutants consisting of 210 chlorinated dibenzo-p-dioxins and dibenzofurans. They are highly toxic and persistent. They are lipophilic and can easily biomagnify in the food chain, hence posing a serious threat to human health. The daily consumption of low-level contaminated food, mainly of animal origin, leads to the accumulation of dioxins in the human body. The exposures of the general human population to dioxins and the specific issues of a risk assessment of dioxin pose serious concerns in public environmental and nutritional health. This paper reviews the analysis of chlorinated dioxins in ground beef. The sources of contamination of chlorinated dioxins in ground beef are first reviewed to form a basis for a clear understanding of the health implications of chlorinated dioxins in the human food chain and why it is necessary to monitor the level of dioxins in animal food products, especially ground beef. The methods of collection, sampling, and processing of ground beef, and the methods of sample clean up prior to the analysis, are reviewed. Emphasis is laid on the new techniques that are available and that might be effective in the analysis of chlorinated dioxins in ground beef. Among these new methods and techniques are: the synergistic combination of ELISA/GC/MS, direct sample introduction to /GC/MS-MS, automated clean-up method, and the supercritical fluid extraction methods. The possible treatments of results from each method and technique are discussed and their respective efficiencies are compared. Finally, quality control and quality assurance parameters are evaluated for levels of accuracy, reproducibility, and precision.

Determination of Pyrethroid Insecticides in Crude and Canned Vegetable Samples by Supercritical Fluid Chromatography

A supercritical fluid chromatography method for the determination of seven pyrethroid insecticides (allethrin, resmethrin, phenothrin, permethrin, tetramethrin, cypermethrin, deltamethrin) and one of their common metabolites, phenoxybenzyl alcohol, in whole and peeled potatoes and mixed vegetables was developed. The efficiencies of the two extraction techniques, supercritical fluid extraction and microwave-assisted extraction, for the extraction of pyrethroids from vegetable samples were also compared. The retention times of various pyrethroids ranged from 8.4 to 22.9 min, while all of the peaks were well-resolved and distinctly identified. The limits of detection of pyrethroid insecticides ranged between 0.31 and 0.54 ppm, whereas the limits of detection of phenoxybenzyl alcohol was 0.62 ppm. The recoveries of pyrethroid insecticides from whole potatoes, peeled potatoes, and mixed vegetables ranged as 93.83–99.8%, 92.3–105.8%, and 93.67–102.7%, respectively, with the use of supercritical fluid extraction. The corresponding recovery ranges while using microwave-assisted extraction were 94.2–102%, 96.6–101.2%, and 96–103.2%. These findings suggested that supercritical fluid chromatography was a sensitive and rapid technique for the analysis of pyrethroids in complex matrices, such as vegetables, fruits, and other agricultural products.

Congener Specific Determination of Polychlorinated Biphenyls (PCBs) in Human Milk

Eighteen congeners Polychlorinated biphenyls (PCBs) congeners were analyzed in 38 human milk samples collected from different ages living in Eastern and Central provinces in Saudi Arabia. The PCB profile was dominated by higher chlorinated congeners. Non-ortho PCB congeners which have the highest Toxic Equivalency Factor (TEF) values were detected in all of individual samples. PCB-81 and PCB-153, the most dominating PCB congeners, which might therefore be used as an indicator for sum PCBs. Toxic Equivalents Factor (TEF) for mono-ortho substituted PCB congeners indicated higher exposure to toxic PCBs in Eastern province rather the Central due to main petroleum industry activities, but estimated daily intakes for both provinces indicate that infants consuFming mother’s milk are not at risk of adverse effects caused by PCBs. Our study builds the first database in Saudi Arabia research of human milk samples.

Levels, Sources, and Risk Assessment of Polychlorinated Biphenyls (PCBs) in Soils from Industrial Areas: A Case Study from Saudi Arabia

ABSTRACT The objective of this study was to assess the pollution levels, sources, and human health risk of polychlorinated biphenyls (PCBs) in soils of industrial areas of the central and eastern regions of Saudi Arabia. Therefore, the surface soil samples from industrial areas (cement kiln, oil refinery, electric power plant, steel industry, and desalination plant) were collected and analyzed by High-Resolution Gas Chromatography-Mass Spectrometry/Mass Spectrometry-Time of Flight (HRGC-MS/MS-TOF) to quantify the levels of 26 PCBs (including 12 dioxin-like PCBs and 14 indicator-PCBs). The investigated 26 PCBs were detected in all soil samples. The total PCBs concentration (from tri-CBs to hepta-CBs) ranged from 171 to 4892 pg g−1 with an average of 1369 pg g−1 in soils of the central region and of 142–1231 pg g−1 with an average of 302 in soils of the eastern region, showing higher values at cement factory and/or oil refinery sites. Overall, the indicator-PCBs were the main congeners and contributed dominantly to the total mass of PCBs in comparison with the dioxin-like PCB congeners, with the most abundant for PCB-180 in the soil samples of the central region. Among individual dioxin-like PCBs, PCB-126 had the highest average value of the toxicity equivalence (TEQ). The TEQ values of ∑12dioxin-like PCBs did not exceed the Canadian soil quality guidelines of dioxin (4 pg TEQ g−1). Based on human health risk assessment via ingestion, dermal contact, and inhalation, low adverse effects of PCBs could be expected as indicated by lower values of cancer risk (≤10−6). The principal component analysis indicated that there is a different source of PCBs with similar or different PCB profiles.

Distribution Ratios of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Soils

Distribution ratios and sources of polycyclic aromatic hydrocarbons (PAHs), including Fluoranthene (Flt), Pyrene (Pyr), Benzo(a)pyrene (BaP), Benzo(k)fluoranthene (BkP), Indeno(1,2,3-cd)pyrene (IP), Benzo(ghi)perylene (BgP) in urban surface and subsurface soil collected from Riyadh city, Saudi Arabia was studied. The sum of the six PAHs ranged from 30.5-1016.6 ng g -1 with an average of 286.6 in surface samples and from 25.5-1501.7 ng g -1 with an average of 287.9 ng g -1 in subsurface samples. The magnitude of the PAHs was found in the following order: Pyr > Flt > BgP > IP > BkF > BaP. The ratios of benzo(a)pyrene to benzo(ghi)perylene (BaP/BghiP) indicated that diesel and gasoline vehicular exhausts were the predominant local emission sources of PAHs. The maximum values of Ind/(Ind+BgP) and Flt/(Flt+Pyr) indicated predominantly that the sources of these PAHs are pyrogenic sources due to combustion. It was also observed that soil samples of industrial areas possess the highest PAHs concentrations, and that the PAHs concentrations decreased with increasing distance from Riyadh city. Original Research Article EL-Saeid and Sapp; JALSI, 9(3): xxx-xxx, 2016; Article no.JALSI.30051 2