Organochlorine contamination in some marketable fish in Egypt

Ten organochlorine compounds were analyzed in four species of fish (Bouri Mugil spp., Denis Sparus auratus, Moza Boops boops and Mousa Pegusa lascaris), from four Egyptian governorates (South Sinai, Suez, Port-Said and Demietta). Although all fish studied are bottom or near-bottom feeders, remarkable variations between studied species were noticed. The grand total values recorded at the studied governorates were in descending order: Bouri>Denis>Moza>Mousa. The highest concentration of pesticides was recorded in Demietta governorate fish (20-211 ng/g of wet weight) and the p,p'-DDE dominated over the other p,p'-isomers in all studied fish, while dieldrin was the dominated in the studied cyclodiene compounds. However, hexachlorobenzene (HCB) occurred at all studied governorate fish except Mousa fish from South Sinai. Toxaphene was detected only in fish (Bouri, Denis, and Mousa) from Demietta governorate. Chlordane was not detected in any studied fish. The level of organochlorine pesticides contamination in fish from the studied governorates is relatively low and should not pose a health risk to consumers.     

Effect of dimethoate on the immune system of female mice

The functional status of the immune system of female mice exposed to a single oral dose of dimethoate (16 mg/kg) was evaluated by assessing cell mediated and humoral immune responses, in addition to the effect of dimethoate on spleen and body weights after different time intervals. The data showed that dimethoate caused a time-depended decrease in spleen weights in the absence of a change in body weights. The immunologic effect of dimethoate to female mice produced a dose-dependent decrease in the number of the rosette forming cells (total and active erythrocyte rosette). The ability of splenocytes to proliferation in response to mitogens; phytohemagglutinin (PHA) for T cell and lipopolysaccharide (LPS) for B cell were significantly decreased at the different times. As compared to control, a significant decrease in serum total immunoglobulins (Ig) and IgM was found, while IgG was non-significant deceased. Results of this study also revealed that dimethoate caused a significant decrease in the number of plaque forming cell (PFC/10(6) splenocytes) in a time dependent manner.     

Organochlorines and PCBs in Tilapia zillii from Lake El-Manzala, Egypt

A freshwater fish species, Tilapia zillii, from Lake El-Manzala was analysed for concentrations of several organochlorine pesticides (OCs) and polychlorinated biphenyl (PCBs) in liver, gonads, mesenteric fat, flesh, and digestive tract in mature fish during the breeding season. PCBs and OCs were calculated in ng g^-1 dry weight (dw) in homogenized samples. The obtained results revealed differences in lipid content between these different organs. The females showed a higher lipid content than did males. There was a significant positive correlation between the lipid content and the concentrations of detected organochlorines and PCBs. The results are concomitant with the lipophilicity of studied compounds. However, the recorded concentrations of these studied pollutants still do not exceed the international hazardous levels.     

A novel method for the preparation of silver/chitosan-O-methoxy polyethylene glycol core shell nanoparticles

Uniformly sized silver/chitosan-O-methoxy polyethylene glycol (chitosan-O-MPEG) core shell nanoparticles with different degree of substitution were synthesized. Thus, N-phthaloyl chitosan is reacted with polyethylene glycol monomethyl ether iodide in the presence of silver oxide by the following steps. At first, amino groups of chitosan are protected by fourfold excess of phthalic anhydride. Then N-phthaloyl chitosan is reacted with an appropriate amount of monomethyl ether iodide in the presence of silver oxide and lastly N-phthaloyl groups are removed to yield silver/chitosan-O-MPEG core shell nanoparticles. Structure of prepared silver/chitosan-O-MPEG core shell nanoparticles have been characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction, and scan electron microscopy (SEM-EDX). Experimental results revealed that the prepared silver core particles had the size 18?±?2?nm. Core shell structure with chitosan-O-MPEG-coating had the size 40?±?2?nm.     

Isolation of petroleum and chlorinated hydrocarbons from the same extract

Sequential analysis is an extremely powerful technique for complex samples analysis. For determination of petroleum and chlorinated hydrocarbons, the same sample is divided into two parts. One part is utilized to extract the petroleum hydrocarbons and the second part is used to extract the organochlorine compounds because petroleum hydrocarbons usually appear in higher concentrations and interfering with organochlorine compounds. This analysis method required more solvent, time, and more sample volume. The analytical strategy, in this paper, involves the use of effective and efficient but simple techniques for petroleum hydrocarbons and chlorinated hydrocarbons separation. A clean‐up procedure is presented, by which these compounds are isolated from aliphatic as well as polyaromatic hydrocarbons through a combination of HPLC and adsorption chromatography on a florisil microcolumn. Mass spectrometric identification was used as confirmation method. GLC equipped with ECD and FID for organochlorine and petroleum compounds analysis, respectively.     

WATERSHED MODELS AND THEIR APPLICABILITY TO CONJUNCTIVE USE MANAGEMENT1

ABSTRACT: Techniques employed to simulate infiltration and subsurface ground-water flow were examined for a number of available watershed models. The large number of processes that these models simulate prohibits detailed analysis of subsurface flow, due to excessive computer and data requirements. Such models emphasize surface flow and include only that portion of water lost to the subsurface and the portion returned to the stream as baseflow. Problems were examined in adopting conjunctive use models, which allow the coordinated exploitation and management of both surface and ground-water resources. The application of conjunctive use models in water resources management is expected to increase dramatically over the next decade.     

Effects of Rainfall and Ground‐Water Pumping on Streamflow in Mākaha,O’ahu,Hawai’i1

Abstract: Land‐use/land‐cover changes in Mākaha valley have included the development of agriculture, residential dwellings, golf courses, potable water supply facilities, and the introduction of alien species. The impact of these changes on surface water and ground water resources in the valley is of concern. In this study, streamflow, rainfall, and ground‐water pumping data for the upper part of the Mākaha valley watershed were evaluated to identify corresponding trends and relationships. The results of this study indicate that streamflow declined during the ground‐water pumping period. Mean and median annual streamflow have declined by 42% (135 mm) and 56% (175 mm), respectively, and the mean number of dry stream days per year has increased from 8 to 125. Rainfall across the study area appears to have also declined though it is not clear whether the reduction in rainfall is responsible for all or part of the observed streamflow decline. Mean annual rainfall at one location in the study area declined by 14% (179 mm) and increased by 2% (48 mm) at a second location. Further study is needed to assess the effect of ground‐water pumping and to characterize the hydrologic cycle with respect to rainfall, infiltration, ground‐water recharge and flow in the study area, and stream base flow and storm flow.     

Estimating Hydraulic Properties of Volcanic Aquifers Using Constant‐Rate and Variable‐Rate Aquifer Tests1

Abstract: In recent years the ground‐water demand of the population of the island of Maui, Hawaii, has significantly increased. To ensure prudent management of the ground‐water resources, an improved understanding of ground‐water flow systems is needed. At present, large‐scale estimations of aquifer properties are lacking for Maui. Seven analytical methods using constant‐rate and variable‐rate withdrawals for single wells provide an estimate of hydraulic conductivity and transmissivity for 103 wells in central Maui. Methods based on constant‐rate tests, although not widely used on Maui, offer reasonable estimates. Step‐drawdown tests, which are more abundantly used than other tests, provide similar estimates as constant‐rate tests. A numerical model validates the suitability of analytical solutions for step‐drawdown tests and additionally provides an estimate of storage parameters. The results show that hydraulic conductivity is log‐normally distributed and that for dike‐free volcanic rocks it ranges over several orders of magnitude from 1 to 2,500 m/d. The arithmetic mean, geometric mean, and median values of hydraulic conductivity are respectively 520, 280, and 370 m/d for basalt and 80, 50, and 30 m/d for sediment. A geostatistical approach using ordinary kriging yields a prediction of hydraulic conductivity on a larger scale. Overall, the results are in agreement with values published for other Hawaiian islands.     

Synthesis of Chitosan@activated Carbon Beads with Abundant Amino Groups for Capture of Cu(II) and Cd(II) from Aqueous Solutions

In this study, chitosan and bio-based activated carbon obtained from sugarcane bagasse biowaste were used for the synthesis of efficient sorbent for Cu(II) and Cd(II) ion via precipitation method. The prepared material was enriched with amino groups through grafting tetraethylenepentamine and tested for heavy metal remediation from water samples. The influence of pH was investigated showing optimum sorption at pH 6 for Cu(II) and Cd(II). Sorption tests, explained by means of the most common sorption models, evidenced that the best performances were reached pointing out the promising application of the prepared sorbent for water purification treatments: Uptake kinetics are relatively fast: the equilibrium was reached within 140 min; and the kinetic profiles were preferentially fitted by the pseudo-second order rate equation. Sorption isotherms are fitted by Langmuir equation. The sorbent showed high metal ion sorption capacity with negligible influence of ion strength. The maximum sorption capacities reached 3.44 and 2.38 mmol g^??1 for Cu(II) and Cd(II), respectively at 298 K. Thermodynamic parameters were evaluated through variation of temperature. The sorption is unfavorable at elevated temperatures. Metal ions were successfully desorbed using 1 M HNO₃ solution.