Magdy T. Khalil

The physical and chemical environment of Lake Manzala, Egypt

The location, morphometry, climatic conditions, water balance, hydrology and hydrochemistry of lake Manzala were investigated.Mean annual salinity declined by about 82.7% since 1921, from 16.7‰ to 2.9%‰ during 1985/86. The nutrient loading increased two or threefold over the past 20 years.These changes are attributed to an increase of the inflow of sewage and agricultural drainage water and restriction of water inflow at the Gamil Lake-Sea Connection since the late 1960s and early 1970s.

Plankton and primary productivity of Lake Manzala, Egypt

Primary production and distribution and abundance of phyto- and zooplankton of lake Manzala were investigated from June 1985 to June 1986.Primary production varied from 4.1 to 28.7 g O2 m−2 d−1 with the highest values 24.2 and 28.7 g O2 m−2 d−1 recorded in the eastern and southern sectors and the lowest value 4.1 g O2 m−2 d−1 recorded in the northern sector. The seasonal mean production for the lake was estimated at 13.3 g O2 m−2 d−1.Mean phytoplankton abundance ranged from 32.7 107 to 76.1 107 cells m−3 with a mean value of 48.107 cells m−3. Diatoms were the dominant phytoplankton group comprising 52 to 90 % by number. The greatest relative abundance (87 to 90%) was recorded in the southern sector.Mean zooplankton abundance ranged from 30.1 103 to 44.4 103 organisms m−3 in the eastern sector to 5.5.103 in the northern sector. In response of eutrophication, the species composition changed significantly over the last 20 years. Cladocerans represented less than 1% of zooplankton during 1959/60, but 75% in 1985/86. Rotifers constituted 40% in 1959/60, and only 1% in 1985/86. Cirriped larvae declined from 21% to 1%.

Changes in the mullet fishery of Lake Manzala, Egypt

Growth rates of the main mullet species (Liza ramada andMugil cephalus) in Lake Manzala are low compared to those in other Egyptian lakes. But average growth rates during the period 1989–1993 were relatively faster than in the 1960s. Spawning and migration seasons have been determined for every species, and their distribution in the lake, in terms of certain ecological parameters (salinity, turbidity and dissolved oxygen) have been investigated. Changes in the mullet fishery in the lake during the past 70 years have been studied. Due to an increase in nutrient loading and a decrease in salinity, mullet declined from 65 per cent of the total catch during the 1920s to only 2.2 per cent during the early 1980s. As a result of fisheries management and development programmes from 1989 to 1993, mullet production increased to 9.2 per cent of the total catch.

Factors affecting the performance of horizontal flow constructed treatment wetland vegetated with Cyperus papyrus for municipal wastewater treatment

ABSTRACT The effect of hydraulic loading rate (HLR) and hydraulic retention time (HRT) on the bioremediation of municipal wastewater using a pilot scale subsurface horizontal flow constructed treatment wetland (HFCTW) vegetated with Cyprus papyrus was investigated. Different HLRs were applied to the treatment system namely 0.18, 0.10, and 0.07 m3/m2. d with corresponding HRTs of 1.8, 3.2, and 4.7 days, respectively. The flow rate was 8 m3/d, and the average organic loading rate (OLR) was 0.037 kg BOD/m3/d. Results showed that the performance of the HFCTW was linearly affected by decreasing the HLR and increasing the HRT. The highest treatment efficiency was achieved at HRT (4.7 days) and HLR (0.07 m3/m2. d). The percentage reductions of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS) were 86%, 87%, and 80%, respectively. Satisfactory nutrient removal was obtained. Also, removal of 2–3 logs of bacterial indicators of pollution was achieved. The dry biomass of Cyperus was 7.7 kg/m2 and proved to be very efficient in nitrification processes due to high diversity of the roots that increase the treatment surface area.

Fisheries of Egyptian Delta Coastal Wetlands; Burullus Wetland Case Study

The occurrence of brackish and saline waters in Delta Egyptian wetlands during the seventies and early eighties of the last century have resulted in a large variety of fish species inhabiting these ecosystems; approximately 32 species were recorded during these periods. Decreasing salinity and domination of drainage water during the last four decades has led to a change in species composition and biodiversity of fish and other organisms. A field survey conducted during 2014 showed that the diversity of fish in the Burullus wetland has declined from 32 to 25 species. All the species which have disappeared are of marine affinity. On the other hand, the total production of this wetland has increased gradually from 7,349 tonnes in 1963 to 63,980 tonnes in 2014.

Physical and Chemical Properties of Egypt’s Coastal Wetlands; Burullus Wetland as a Case Study

Egypt’s coastal wetlands are located along the Mediterranean coast; four in the northern part of the Nile Delta (Manzala, Burullus, Mariout and Edko) and one in the northern part of the Sinai (Bardawil). According to the map of the world distribution of arid areas, northern Egypt belongs to the Mediterranean arid region. The climatic conditions are warm summer (20–30°C) and mild winter (10–20°C). The aridity index ranges between 0.03 and 0.2 in the northern areas and less than 0.03 in the south (hyperarid region).

Macrobenthos Diversity of Egypt’s Coastal Wetlands

Different studies have revealed that Egypt’s coastal wetlands have become more dulcitude, eutrophic, and productive ecosystems, owing to remarkable increase in amount of discharging agricultural drainage, loaded with nutrients, into the wetlands via the southern drains. Decreasing salinity and nutrients loading have led to significant impacts on biodiversity and abundance of macrobenthos in these wetlands, such as in Burullus. Thirty-four macrobenthic species, belonging to three main groups (Arthropoda, Annelida, and Mollusca) were recorded in this wetland during 2013. There was no sign of occurrence of eight marine species, which have been previously recorded in this ecosystem during the 1970s and 1980s of the last century. It is worth mentioning that 17 species (freshwater in origin) were recorded for the first time in the Burullus wetland during 2003.

Separation of a compound effective against Biomphalaria alexandrina snails from the filtrate of Penicillium janthinellum

Biomphalaria alexandrina snails, as intermediate hosts of schistosomiasis, play a central role in dissemination of the disease. Control of these snails by chemical molluscicides adversely affects the aquatic environment, causing toxic and carcinogenic effects on non-target organisms. Searching for promising substances from biological origin becomes an urgent need to overcome these drawbacks. Screening tests were carried out on 236 fungal genera isolated from the habitat of freshwater snails in four Egyptian governorates. Twenty species were effective against B. alexandrina snails, but the most potent was Penicillium janthinellum as the value of LC50 was 1.03%. Chemical analyses of this filtrate resulted in the separation of a compound effective against snails; it was identified as methyl gallate. Protein electrophoresis showed that both fungal filtrate and methyl gallate affect the protein pattern of snails’ haemolymph. Little or no mortality of Daphnia pulex individuals was observed after their exposure to sub lethal concentrations of each treatment.

Thoracoscopic tetracycline poudrage for pleurodesis in malignant pleural effusion

Introduction: Malignant pleural effusion (MPE) is a common problem and a real challenge to pulmonologists and oncologists. The optimum management of MPE depends on several factors, including patient’s symptoms and primary tumor status. Complete drainage and pleurodesis to prevent recurrence is usually needed. Tetracycline, talc, and bleomycin are considered the primary sclerosing agents. Aim of the study: The aim of the study was to investigate the feasibility, effectiveness, and safety of thoracoscopically insufflated tetracycline powder to achieve pleurodesis in patients with MPE. Patients and methods: Twenty patients with recurrent pleural effusion that proved to be malignant, or showing a picture highly suggestive of pleural malignancy at thoracoscopy, were included in the study. They were subjected to tetracycline poudrage (35 mg/kg) through medical thoracoscopy. Following discharge, patients were followed up at 3 and 6 months; the primary outcome was the measure of pleurodesis failure, defined as the reaccumulation of pleural fluid requiring further pleural intervention. Results: Of the 20 patients included in this study, five were excluded from evaluation (two because of failure of lung re-expansion and three because of death within 2 months of the procedure). The overall success rate of thoracoscopic tetracycline poudrage pleurodesis in the 15 patients with MPE who completed the study was 86.6%. There was no recorded mortality or significant complications. Conclusion: From this pilot study, we can conclude that thoracoscopy with tetracycline poudrage is an easy, safe, and effective method for performing pleurodesis in MPE.

Chest ultrasound versus chest computed tomography for imaging assessment before medical thoracoscopy

Background and objective The aim of this work was to assess the concordance between chest ultrasound (US) and chest computed tomography (CT) findings before medical thoracoscopy (MT) and the impact of the findings on the conduct and outcome of MT. Materials and methods The study was conducted prospectively on 52 patients referred for MT. All patients received chest X-ray (CXR), chest US, and chest CT before the procedure. Images were evaluated and findings were correlated with thoracoscopic findings. Results US findings were discordant with CT findings regarding consistency, septation, and loculation of effusion in 24/52 patients, with US detecting the findings in 24/24 patients. None of these findings was detectable on CT. US was superior to CT in detection of diaphragmatic nodules (16/52, 3/52, respectively). US findings affected MT conduct in 20/52 cases and outcome in 5/40 cases, and they were consistent with MT findings in 39/40 cases; US and CT missed septation in one case. US findings were concordant with CT findings regarding site and size of effusion and pleural masses, sizable nodules, and thickening. US missed discrete small parietal nodules in 10/52, consolidation in 2/52, mediastinal lymphadenopathy in 6/52, and mediastinal shift in 42/52 cases. CXR could identify mediastinal shift but none of other CT findings were missed by US. None of US-missed abnormalities directly altered MT management. Conclusion US identifies more explicitly the imaging information relevant to MT compared with chest CT. Pre-MT imaging workup can be limited to CXR and US, reserving chest CT for cases in which US is technically unrevealing.