Mohamed Tawfic Ahmed

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.

Residues of some chlorinated hydrocarbon pesticides in rain water, soil and ground water, and their influence on some soil microorganisms

Abstract Residues of lindane, heptachlor, heptachlor epoxide, aldrin, endrin, dieldrin, and DDT were monitored in rain water, the soil profile, and ground water. Heptachlor and heptachlor epoxide were detected in rain water in 1995 and 1996. The total concentrations of organochlorine detected were 4.7 and 10.6 μg L−1 for 1995 and 1996, respectively. Top soil showed a wider spectrum and higher concentrations of organochlorines detected. The total concentration detected in top soil was 9.5 μg kg−1, while concentrations detected at 50 cm depth mounted to 8 μg kg−1. Samples collected at 1 m depth had no detectable concentrations of any compound. Residues detected in ground water were higher than residues reported in many European countries. Residues detected in top soil and rain water caused a significant depression in soil heterotrophic bacteria and fungi. They also caused a sharp decrease in nitrifying bacteria.

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.

The influence of baking fuel on residues of polycyclic aromatic hydrocarbons and heavy metals in bread

The influence of fuel type used to bake bread on the spectrum and concentrations of some polycyclic aromatic hydrocarbons and heavy metals in baked bread was assessed. Bread samples were collected from different bakeries operated by either electricity, solar, mazot or solid waste and their residue content of PAHs and heavy metals was assessed. The total concentration of PAHs detected in mazot, solar, solid waste and electricity operated bakeries had an average of 320.6, 158.4, 317.3 and 25.5 microgkg(-1), respectively. Samples collected from mazot, solar and solid waste operated bakeries have had a wide spectrum of PAHs, in comparison to that detected in bread samples collected from electricity operated bakeries. Lead had the highest concentrations in the four groups of bread samples, followed by nickel, while the concentrations of zinc and cadmium were the least. The concentration of lead detected in bread samples produced from mazot, solar, solid waste and electricity fueled bakeries were 1375.5, 1114, 1234, and 257.3 microgkg(-1), respectively. Estimated daily intake of PAHs based on bread consumption were 48.2, 28.5, 80. 1, and 4.8 microg per person per day for bread produced in bakeries using mazot, solar, solid waste and electricity, respectively. Meanwhile, the estimated daily intake of benzo (a) pyrene were 3.69, 2.65, 8.1, and 0.81 microg per person per day for bread sample baked with mazot, solar, solid waste and electricity, respectively. The daily intake of lead, based on bread consumption was 291, 200.5, 222, and 46.31 microg per person per day for bread sample baked with mazot, solar, solid waste and electricity, respectively. The present work has indicated the comparatively high level of daily intake of benzo (a) pyrene and lead in comparison to levels reported from many other countries and those recommended by international regulatory bodies. It is probable that residues detected in bread samples are partially cereal-borne but there is strong evidence that the process of baking and the gases emitted are responsible for most of the contamination load.

Residues of chlorinated hydrocarbons, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in some marine organisms in Lake Temsah, Suez Canal, Egypt

Lake Temsah is the end point where some municipal, agricultural and industrial wastewaters are discharged. The lake is connected to the Suez Canal where large volumes of petroleum oil are passed from producing countries in the Arab Gulf to Europe and North America. The lake is the main source of fish for the area of Ismailia and a recreational site where the tourism industry thrives. Recently, numerous complaints have been made about the level of pollution in the lake which affects to a significant extent fishing and tourism industries. In the present study, residues of some chlorinated hydrocarbon pesticides, polycyclic aromatic hydrocarbons and polychlorinated biphenyls were monitored in some of the lakes organisms. Mullet ( Mugil cephalus , usually living in the water column), crab ( Lupa pelagcus , an intertidal organism) and a bivalve ( Ruditapes decussata, a benthic sedentary organism) were selected as representatives of various strata of the lake ecosystem. Residues of an endosulfan, DDE, Dieldrin, heptachlor epoxide and Dicofol were detected. Aroclor residues were not seen. Endosulfan had the highest detected concentration of all organochlorines: concentrations were 24.1, 52.3, 124.8, and 65.6 µg kg -1 in fish skin, fish gills, fish muscles and bivalves respectively. DDE was the most frequent detected organochlorine, detected in all samples, while Dieldrin was only detected in bivalves and crab. The concentration of polycyclic aromatic hydrocarbons was lowest in fish skin, 2.7 µg kg -1 , and highest in bivalves, 48.9 µg kg -1 . Fluorine and anthracene were the most frequently detected polycyclic aromatic hydrocarbons compounds, while acenaphthene was the least detected. The highest concentrations of organochlorines and polycyclic aromatic hydrocarbons, 108 and 48.9 µg kg -1 , respectively, were detected in bivalves. Bivalves also had the widest spectrum of detected organochlorines and polycyclic aromatic hydrocarbons. All tested organisms showed a higher ability to accumulate organochlorines in comparison to polycyclic aromatic hydrocarbons. Results also showed some indications that factors other than fat content may have some influence on the accumulation of persistent contaminants in biological tissues.

Field dissipation and health hazard assessment of Fenhexamid on Egyptian grapes

Dissipation behavior and hazard assessment of the fungicide fenhexamid applied to grapes were investigated under climatic conditions in Egypt. Fenhexamid residues were extracted from grape samples with ethyl acetate. The extract was cleaned up by QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, and determined by gas chromatographic method (GC-μECD). The average recoveries ranged between 94.2% and 99.4% with associated relative standard deviation not exceeding 12%. The estimated limit of quantification for fenhexamid was 0.1 mg/kg. The field results showed that fenhexamid dissipated rapidly from grapes and had a half-life of approximately 4.21 days. Hazard assessment was evaluated by using the hazard quotient (HQ). Data showed that the HQ value was significantly less than HQ = 1. Results indicate that hazard of fenhexamid use in grape even at 1.5-fold higher than recommended dosage was negligible to humans. This study could provide guidance for safe and reasonable use of fenhexamid in grapes and prevent health problems to consumers. However, further hazard assessment studies are needed to ascertain the hazard of fenhexamid residues on grape to vulnerable groups, including children, pregnant women, and elderly consumers.

Residues of PCDD, PCDF, and PCBs in some marine organisms in Lake Temsah, Ismailia, Egypt

Residues of PCDDs/F, non-ortho, mono-ortho PCBs, and other PCBs were monitored in the tissues of mullet fish, bolti fish, bivalves and crab taken from Lake Temsah, at Ismailia, Egypt. Results showed that 2,3,7,8 Tetra CDD and 1,2,3,7,8 Penta CDD were the most frequently detected PCDD congeners. Similarly, 2,3,7,8 Tetra CDF, 1,2,3,7,8 Penta CDF and 2,3,4,7,8 Penta CDF were the most frequently detected PCDF congeners. No relationship was apparent between the concentrations of detected PCDDs congeners and the degree of chlorination, except with crab samples in which an increase in the chlorination coincided with a decrease in the concentrations of the congeners. In PCDF congeners, detected residues have had a reversed relationship with chlorination increase. In PCDD congeners, Octa CDD had the highest detected concentrations in the two fish species, while in the bivalves and crab, 2,3,7,8 Tetra CDD had the highest concentrations. The mullet fish had the highest total PCDDs concentration, at 0.398 pg/g fresh weight, followed by crab at 0.395 pg/g fresh weight, then bivalves and bolti fish at 0.187 and 0.062 pg/g fresh weight, respectively. In all the examined organisms, the total concentrations of PCDFs were much higher than the total concentrations of the PCDD congeners. The WHO–TEQ values were 11.92, 39.12, 25, and 3.6 pg/g fresh weight, for mullet fish, bolti fish, bivlaves and crab, respectively. The concentration of the mono-ortho congeners CB 118 was the highest detected of all non-ortho and mono-ortho PCBs congeners, with values of 0.382, 0.022, 0.231 and 0.357 ng/g fresh weight, in mullet fish, bolti fish, bivalves and crab, respectively. The WHO–TEQ concentrations were 0.799, 0.003 pg/g fw, 0.05 pg/g fresh weight, 0.676 pg/g, and 0.799 pg/g fresh weight, for the same species, respectively. The total concentration of PCBs 28, 52, 95, 99, 101, 105, 110, 118, 138, 146, 149, 151, 153, 170, 177, 180, 187 were 6.86 ng/g fresh weight for mullet fish, 0.2 ng/g fresh weight, for bolti fish, 2.72 ng/g fresh weight for bivalves and 2.8 ng/g fresh weight for crab, respectively.

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 ADIs. 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.

Dissipation kinetics of novaluron in tomato, an arid ecosystem pilot study

Novaluron, a newly introduced insecticide, is used for control of a number of field pests. However, information regarding novaluron residues and dissipation profile is limited. In this study, dissipation and residual levels of novaluron in tomato under open field conditions were investigated using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) with quick, easy, cheape, effective, rugged (QuEChERS) method. The method was validated using blank samples spiked at three levels and results showed that recoveries ranged from 93% to 99%. Novaluron residues tend to dissipate following first-order rate kinetics with half-life of 2.08 days. Data demonstrated that the use of novaluron at recommended doses would not pose any hazards to consumers. The present results aid to establish the safe use of this pesticide on tomatoes, and possibly on other crops in Egypt.

Residue Levels, Profiles, Emission Source and Daily Intake of Polycyclic Aromatic Hydrocarbons Based on Smoked Fish Consumption, An Egyptian Pilot Study

Residue levels and spectrum of polycyclic aromatic hydrocarbons (PAHs) were determined in smoked fish, and canned smoked fish, collected from grocery shops from Cairo, Giza, Menoufya, and Ismailia governorates, Egypt. Residues of PAHs were monitored using gas liquid chromatography, equipped with a flame ionization detector. The concentrations of ∑13 PAHs in the smoked fish and the canned smoked fish ranged from 36.06–547.1 μg/kg, respectively. Benzo(a)pyrene was not detected in smoked canned fish, while its mean residues in smoked fish amounted to 1.1 μg/kg, corresponding to one fifth of the maximum tolerable limit of 5 μg/kg established by EU. The congeners profile showed that the sources of PAHs in the two brands of smoked fish are mainly petrogenic. Based on smoked fish the daily intake of 13 PAHs and benzo(a)pyrene were 45.59 μg/day and 0.092 μg/day, respectively, while for canned smoked fish the intake was fifteen times lower (3 μg/day), and the intake of benzo(a) pyrene is zero μg/day. Results showed that the consumption of smoked fish would pause some risk to consumers; meanwhile canned smoked fish showed no risk to Egyptian consumers.