Egyptian Lakes Research Articles

Distribution and accumulation of heavy metals in Lake Manzala, Egypt

ABSTRACT Lake Manzala is the largest saline lake and the second largest one among all lakes in Egypt. Heavy metals' contamination is the most fundamental kind of contamination around the world, particularly in Lake Manzala. The purposes of this paper are investigating the relationship between contents of some heavy metals and major oxides of the Quaternary sediments of Lake Manzala islands as well as the correlation coefficient factor among them.Ten samples of both water and superficial bottom sediments had been representing the lake Manzala through summer, 2019 is covering the sources of pollution to carry out this study. Six heavy metals estimated to assess the environmental risk. The elements were analyzed through atomic absorption spectrometer. Concentration of heavy metals Fe> Zn> Pb; Fe> Mn> Zn> Pb> Cu> Cd in water and sediment is recorded within the southern and southeastern parts of the lake. Significant oxides' arrangement is SiO2> MgO> CaO> Na2O> A12O3> K2O> Fe2O3. Eco-toxicological of heavy metals' contamination was among the bottom sediments of Lake Manzala. Target hazard quotients (THQ) for individual metals are arranged within the order; Zn>Pb> Cu> Cd. Therefore, heavy metals should eliminate from the wastewater to protect the people and the environment.

Concentrations of Poorly Studied Technology-Critical Elements Ge, Zr, Mo, Sn, Sb, Hf, Ta, W and Ti in the Sediments of Three Northern Egyptian Lakes

Thirty five Sediment samples were collected from three Northern Egyptian Lakes namely El Burullus, El Manzala and El Bardawil to evaluate for the first time the concentrations of poorly studied technology-critical elements, namely Ge, Zr, Mo, Sn, Sb, Hf, Ta, W and Ti, and how that may be linked to local water quality parameters and other geochemical factors. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine element’s concentration. The results were compared with Upper Continental Crust (UCC) and Nile sediment (ANS). Lake sediments generally have relatively low contents of most elements. The average concentration of Zr, Hf, Ta and W are lower than UCC and ANS in three Lakes. El Bardawil Lake attained the lowest average concentration for all elements except Mo. Correlation analysis revealed that water quality and geochemical properties did not play any important role affecting the metal distribution and the studied metals are generally not affected by the complex lacustrine system of these lakes and their spatial distribution still not affected by the different anthropogenic activates.

Water quality monitoring of Lake Burullus (Egypt) using Landsat satellite imageries.

Lake Burullus is one of the most important coastal lakes in Egypt, as it participates with a considerable amount of fish yield in Egypt. Despite its importance, it is considered as a vulnerable lake, since it is subjected to significant environmental changes caused by various anthropogenic activities. Severe deterioration of its water quality status, as well as a decrease in its water area, has been noticed throughout the last four decades. The main objective of this study is to evaluate the ability of remote sensing for assessing the water quality status of the lake for the period from August 2010 to August 2013. Remote sensing technique was used to retrieve and predict the lake water quality parameter records through the assessment period (August 2010 to August 2013). Stepwise multi-linear regression technique was used to correlate between the field measurements of water quality parameters and the reflectance of remote sensing imageries, and then the derived models were validated. The results revealed the critical status of water quality conditions of the lake, particularly of its southern and southeastern parts. The results showed also that some water quality parameters (Chl-a, TSS, pH, Fe, Zn, Cr, and NH4) can be retrieved from remote sensing imageries with reasonable accuracy (R2 = 0.86, 0.67, 0.65, 0.63, 0.62, 0.61, and 0.6, respectively), while the water quality parameters, which can be predicted, based on calibrated and validated regression models are TSS and Chl-a, with acceptable accuracy (R2 = 0.6 and 0.43, respectively). Lake Burullus needs urgent plans and strategies to protect its water quality from the potential hazards of human activities. The study proved the ability of remote sensing as an effective technique to monitor the changes in water quality conditions of shallow coastal lagoons and to predict with some water quality parameters without field measurements; therefore, it is highly recommended to be used by decision makers.

Evaluation of Water Quality on TNF- α and IL- 1 Immune Genes in Oreochromis Niloticus Fish at El Manzala Lake in Egypt

Lake Manzala is known to be from the most significant sources of inexpensive different fish species for human consumption in Egypt. The Lake receives pollution from various sources; domestic wastewater, industrial wastewater, and agricultural drainage directly without any treatments, which lead to many environmental disorders. The following research was conducted for lake water quality evaluation and how it impacts the expression of Tumor necrosis factor- α (TNF- α) and Interleukin-1 (IL- 1) immune genes. Sampling was done seasonally from October 2015 to September 2016, where water and fish samples were collected from 4 locations in El Manzala Lake after mixing with Bahr El Baqr drain (sampling points were 4 km apart from each other). Average values of dissolved oxygen, chemical oxygen, and biological oxygen demand were 6.7 mg O2/l, 139.4 mg O2/l, 92.8 mg O2/l, respectively. For the Nitrogen group, the average concentration of ammonia, nitrite, and nitrate was 0.7 mg/l, 0.38 mg/l, and 0.38 mg/l, respectively. The average records of total bacterial count and total and fecal coliform suggesting high loads of contaminants, particularly in sampling sites close to Bahr El Baqr drain. The relative occurrence of cyanobacteria in water samples was influenced by increasing lake water temperature. The expression of the immune genes for TNF- α and IL- 1 in Nile Tilapia fish liver was confirmed by RT-PCR. The results showed up-regulation of these genes in the liver of Nile Tilapia fish, especially in warm seasons (summer, late summer). TNF-α and IL- 1 level in Nile Tilapia fish could be used as early diagnostic indicators to different environmental events and also are helpful and reliable bioindicators in estimating pollutants of the aquatic environment. High levels of pollution in El Manzala Lake were recorded in this study that may proceed with health risks to a human. Therefore, the Lake needs proper policies to protect and preserve its ecological integrity and biodiversity.

A novel horizontal subsurface flow constructed wetland planted with Typha angustifolia for treatment of polluted water.

Rapid population growth and urbanization has put a lot of stress on existing water bodies in most developing countries such as the Marriott Lake of Egypt. Three constructed wetland configurations including Typha angustifolia planted with enhanced atmospheric aeration by using perforated pipes networks (CWA), planted without perforated pipe network (CWR), and a control non-planted and without perforated pipes wetland (Control) were used in the study. Changes in physicochemical properties and microbial community over four seasons and hydraulic loading rate (HLR) (50, 100, 200, 300, and 400Lday-1m-1) were monitored using influent from Marriott Lake in Egypt. Overall, the removal performance followed the sequence CWA>CWR>control. Turbidity removal of 98.4%; biochemical oxygen demand (BOD5) removal of 83.3%; chemical oxygen demand (COD) removal of 95.8%; NH3-N removal of 99.9%; total nitrogen (TN) removal of 94.7%; NO3--N and NO2--N increased; total P (TP) removal of 99.7%, Vibrio sp. of 100%, Escherichia coli 100%; total bacterial count of 92.3%; and anaerobic bacteria reduction of 97.5% were achieved by using CWA. Seasonal variation and variation in HLRs had significant effect on performance. The modified planted CWA system enhances the removal of pollutants and could present a novel route for reducing the cost associated with integrating artificial aeration into wetlands.

Biomonitoring potential of the native aquatic plant Typha domingensis by predicting trace metals accumulation in the Egyptian Lake Burullus

The ability of the native emergent macrophytes Typha domingensis for monitoring pollution with trace metals in Egyptian Lake Burullus was investigated through developing regression models for predicting their concentrations in the plant tissues. Plant samples (above-ground shoot and below-ground root and rhizome) as well as sediment samples were collected monthly during one growing season and analyzed. The association of trace metals concentration with several sediment characteristics (pH, organic matter, clay and silt) was also studied using the simple linear correlation coefficient (r). The concentration of some trace metals was significantly proportional to its values in the sediment such as Cd in the shoot, rhizome and root, Fe in the rhizome, and Ag in the root. There was positive relationship between the bioaccumulation factor (BAF) of Ag, Cd, Fe, Pb and Zn and sediment pH, organic matter and clay content. The developed regression models were significantly valid with high model efficiency and coefficient of determination, and low mean normalized average error. Trace metals were accumulated in the below-ground root and rhizome rather than in the shoot. Only Ag, Co and Ni provided bioaccumulation factor (BAF) < 1, while Ag was the only trace metal that could be transferred to some extend from the root to the rhizome and from there to the shoot [translocation factor (TF) 2.55 and 1.15, respectively]. Typha domingensis in Lake Burullus could be regarded as a bioindicator of trace metals pollution, and a good candidate as phytoremediator for Ag. The information on the phytoremediation capacity of T. domingensis certainly helps to solve contamination problems at Egyptian Lake Burullus region using this native plant.

Steps for rehabilitation of a Lake suffering from intensive pollution; Lake Mariut as a case study

Due to the acute water scarcity facing many urban areas, the water resource management, and lake rehabilitation become a global interest. Before applying the appropriate approach in the rehabilitation (restoration) of a hypereutrophic lake, the assessing of the point sources of pollution and their effects are A MUST. Lake Mariut is an example of lentic polymictic closed coastal Egyptian lake. The economic and recreational values of Lake Mariut were deteriorated since 1960s, as a result of using its Main Basin as a sink of wastewaters discharged from the agricultural Umum Drain and the heavily polluted Qalaa Drain mixed with primary treated sewage waters from Alexandria East Wastewater Treatment Plant. The aim of the current study is to find the suitable solution/s for the Lake Mariut Main Basin restoration, by (1) studying the general characteristics of its drainage water system (Umum and Qalaa Drains) at their downstream parts before reaching the lake at its southern side as well as the adjacent non-polluted Lake Mariut Fishery Basin. (2) Discussing (by calculation) the applicability of two proposed improvement solutions. The results reveal that, in the first the water quality of the anoxic Qalaa Drain must be improved by diluting its waters with oxic Umum Drain waters via Lake Mariut Fishery Basin prior discharging. This solution is found not sounding as it difficult to attain from practical point of view. The other alternative is by diverting the polluted Qalaa Drain point source itself away from Lake Mariut Main Basin water body which is sounding and highly recommended.

Viability of the advanced adaptive neuro-fuzzy inference system model on reservoir evaporation process simulation: case study of Nasser Lake in Egypt

Reliable prediction of evaporative losses from reservoirs is an essential component of reservoir management and operation. Conventional models generally used for evaporation prediction have a number of drawbacks as they are based on several assumptions. A novel approach called the co-active neuro-fuzzy inference system (CANFIS) is proposed in this study for the modeling of evaporation from meteorological variables. CANFIS provides a center-weighted set rather than global weight sets for predictor–predictand relationship mapping and thus it can provide a higher prediction accuracy. In the present study, adjustments are made in the back-propagation algorithm of CANFIS for automatic updating of membership rules and further enhancement of its prediction accuracy. The predictive ability of the CANFIS model is validated with three well-established artificial intelligence (AI) models. Different statistical metrics are computed to investigate the prediction efficacy. The results reveal higher accuracy of the CANFIS model in predicting evaporation compared to the other AI models. CANFIS is found to be capable of modeling evaporation from mean temperature and relative humidity only, with a Nash–Sutcliffe efficiency of 0.93, which is much higher than that of the other models. Furthermore, CANFIS improves the prediction accuracy by 9.2–55.4% compared to the other AI models.

Water quality assessment of Qarun Lake and heavy metals decontamination from its drains using nanocomposites

Qarun Lake is one of the most important lakes in Egypt; it is the shrunken remnant of Moeris Lake. It is a closed ecosystem represented as a tank for discharged agricultural wastewater of El-Fayoum province. To assess the quality of the lake water for fishing and aquatic live utilization, Oregon water quality and metal pollution indices are computed. Based on the obtained results, water of the Qarun Lake is classified as very poor for the fishing utilization, where water quality index changed from 17.05 to 67.4 at the different stations. The metal indices; Pollution index (PI) and metal index (MI); showed that Qarun Lake water undergoes from a several grade of contamination for usage of aquatic life because of the enormous amount of wastes that discharging into the lake. Novel synthesized alginate nanocomposites (alginate, chitosan-alginate, and LDH-alginate and LDH-chitosan-alginate beads) were applied to remove heavy metal such as (Cd2+, Cu2+, Cr6+, Mn2+, Fe2+, Ni2+, Pb2+, and Zn2+) from different wastewater discharging into Qarun Lake. LDH-chitosan-alginate beads the exhibited the maximum removal efficiency that varied between 92.253 and 98.833 % for Cr6+ and Fe2+, respectively; in contrast, the alginate beads recorded the lowest one. The study indicated that the nanocomposite adsorbents, especially, LDH-chitosan-alginate beads are an effective substance for metal removal from different wastewater.

Monitor of Water Quality Using The Grey Mullet (Mugil Cephalus) as Bioindicator in Two Egyptian Lakes

Background-Burullus Lake has brackish water and agricultural, industrial and sewage drainage water represent the major inflows and it represents one of the most subjected lakes to serious pollutants at the delta’s coastline. Mugil cephalus is one of the most important food fish species for the Egyptian people. This study was conducted to explain the effect of water pollution of both Qarun and Burullus Lakes on some biochemical and histological characteristics of mullet collected from both Lakes. Our results showed that water collected from Burullus Lake has higher levels of lead and cadmium than Qarun Lake. The liver function analysis showed that there were no significant differences between levels of GGT in M. cephalus livers collected from both Lakes. ALT and AST were significantly increased in livers of fishes collected from Qarun Lake than Burullus Lake, cholesterol, triglycerides, RF1, RF2, high density lipoproteins (HDL), low density lipoproteins (LDL) and very low density lipoproteins (VLDL) in muscles of the mullet collected from Burullus Lake were highly significant increase, while total proteins were significantly decreased in comparison with mullet of Qarun Lake. Histopathological investigations revealed that livers of mullet cached from both Lakes were suffered from marked area of hemorrhage, aggregates of hemosiderin granules and vacuolated hepatocytes. Ultrastructural observation showed degenerated and swelled cylindrical mitochondria in liver obtained from Burullus Lake with accumulation of lipid droplets and degenerated cytoplasmic organoids. Hepatocyte from Qarun Lake showed apoptotic nuclei, degenerated, swelled and cylindrical mitochondria, lipid droplets and dilated rough endoplasmic reticulum. Von Kupffer cells in liver of both lakes contained abundant lysosomes with corrugated walls and numerous cytoplasmic vacuoles. The kidney sections of mullet of both Lakes showed necrosis in the tubular epithelial lining with scattered apoptotic cells and interstitial inflammatory infiltrate.

Monitor of Water Quality Using The Grey Mullet (Mugil Cephalus) as Bioindicator in Two Egyptian Lakes

Background-Burullus Lake has brackish water and agricultural, industrial and sewage drainage water represent the major inflows and it represents one of the most subjected lakes to serious pollutants at the delta’s coastline. Mugil cephalus is one of the most important food fish species for the Egyptian people. This study was conducted to explain the effect of water pollution of both Qarun and Burullus Lakes on some biochemical and histological characteristics of mullet collected from both Lakes. Our results showed that water collected from Burullus Lake has higher levels of lead and cadmium than Qarun Lake. The liver function analysis showed that there were no significant differences between levels of GGT in M. cephalus livers collected from both Lakes. ALT and AST were significantly increased in livers of fishes collected from Qarun Lake than Burullus Lake, cholesterol, triglycerides, RF1, RF2, high density lipoproteins (HDL), low density lipoproteins (LDL) and very low density lipoproteins (VLDL) in muscles of the mullet collected from Burullus Lake were highly significant increase, while total proteins were significantly decreased in comparison with mullet of Qarun Lake. Histopathological investigations revealed that livers of mullet cached from both Lakes were suffered from marked area of hemorrhage, aggregates of hemosiderin granules and vacuolated hepatocytes. Ultrastructural observation showed degenerated and swelled cylindrical mitochondria in liver obtained from Burullus Lake with accumulation of lipid droplets and degenerated cytoplasmic organoids. Hepatocyte from Qarun Lake showed apoptotic nuclei, degenerated, swelled and cylindrical mitochondria, lipid droplets and dilated rough endoplasmic reticulum. Von Kupffer cells in liver of both lakes contained abundant lysosomes with corrugated walls and numerous cytoplasmic vacuoles. The kidney sections of mullet of both Lakes showed necrosis in the tubular epithelial lining with scattered apoptotic cells and interstitial inflammatory infiltrate.

Short-term changes in phytoplankton assemblages and their potential for heavy metal bioaccumulation – a laboratory study

Abstract This study focused on phytoplankton changes in polluted waters of Lake Manzala and the assessment of heavy metal bioaccumulation capacity during the 15-day laboratory experiment. Phytoplankton samples were analyzed every day and the concentration of zinc, iron and lead in water, in phytoplankton and in filtrate – every fifth day of the experiment. Significantly higher phytoplankton abundance was recorded in water from the El-Boom station (basin I) compared to the New Bahr El-Baqar drain (basin II), followed by distinct differences in its composition and chlorophyll content. However, the most abundant species were the same in both basins, i.e. Chroococcus minor, Microcystis aeruginosa, Actinoptychus octonarius, Aulacoseira granulata, Pantocsekiella ocellata, Kirchneriella obesa and Nephrocytium limneticum. Water in basin I was more polluted with heavy metals compared to basin II. Basin I was characterized by the dominance of cyanobacteria and high relative abundance of chlorophytes compared to basin II, where either cyanobacteria and/or diatoms dominated in the phytoplankton. In the former basin, the highest uptake factors (UFs) were recorded for iron and zinc and the lowest UF for lead. In basin II, the highest UF was determined for zinc, but relatively high UFs were recorded also for iron and lead. The presented results suggest that phytoplankton can contribute to natural biosorbents of heavy metals in Egyptian lakes.

Relation of Some Hydrochemicals with Hydrogen Sulphide Levels in Sediments of Lake Burullus, Egypt

Lake Burullus, as one of the northern deltaic lakes in Egypt, is an important economic, recreational and Fish breeding reservoir. The study used nine georeferenced stations to assess hydrogen sulphide (H2S) levels, its relationship with some selected hydrochemical parameters, and the implication on this lake’s biota.&#x0D; The study reveals that areas mostly affected by drainage water with high load of organic matter, aid to the production of H2S into sediments and dispersion to water. The results indicate that H2S levels in lake sediments increase with increasing water temperature, biological oxygen demand (BOD) and load of organic matter (OM) in water. On the other hand, clear water areas with high oxygen levels aid in reducing levels of H2S in sediments as proved from correlation analysis. The positive correlation between variables as OM and BOD with H2S was observed using the distribution maps. The amount of different wastes, particularly in large quantities, increase the level of H2S, and therefore affected biota so it is highly recommended to treat wastewater to conserve the biodiversity of this lake.

Potentially toxic elements in saltmarsh sediments and common reed (Phragmites australis) of Burullus coastal lagoon at North Nile Delta, Egypt: A survey and risk assessment

Burullus lagoon is the second largest lake in Egypt. However, there has never been a comprehensive survey which studied nineteen potentially toxic elements in sediments and plants and evaluated the associated potential risk. Thus, we aimed to study the total and potentially available content of As, Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Sb, Se, Sn, Tl, V, and Zn in the sediments and common reed (Phragmites australis) at thirty two sites along the entire lagoon and connected drains. Contamination Factor (CF), Pollution Load Index (PLI), Geo-accumulation Index (Igeo), and Enrichment Factor (EF) were calculated to assess the grade of contamination. Element accumulation factor (AF) and bio-concentration ratio (BCR) were also calculated. Aluminum showed the highest median (mg kg−1) total content (41,200), followed by Fe (30,300), Mn (704.7), V (82.0), Zn (75.5), Cr (51.2), Cu (47.8), Ni (44.3), As (31.9), Tl (24.6), Co (21.4), Se (20.3), Sb (17.6), Sn (15.6), Mo (11.3), and Hg (16.6 μg kg−1). Values of the EF, CF, and Igeo showed that the sediments were heavily contaminated with As, Sb, Se, Tl, Mo, Sn, Co, Ni, and Cu. The drained sediment had significantly higher values of total and potentially available element content than the lagoon sediments. Sediments of the middle and western area showed significantly higher contents of total and available elements than the eastern section. The BCR and AF values indicate that the studied plant is efficient in taking up high amounts of Zn, Fe, As, Sn, Tl, Ni, Mo, Mn; then Co, Cu, and V. The results exhibit a dramatic contamination at certain sites of the lagoon, and the studied PTEs have a predominant role in contamination-related ecological risk. Further investigations concerning redox-induced mobilization of PTEs in sediments, the risk of fish contamination and the potential health hazards are highly recommended.

Water quality analysis and model simulation for the second largest polluted lake in Egypt

This study investigated the spatial variation in the water quality parameters of Burullus Lake using multivariate analysis and MIKE21 model. The lake was classified into zone-1 at north-east (Z1), zone-2 at south-east (Z2), zone-3 at north-middle (Z3), zone-4 at south-middle (Z4), zone-5 at north-west (Z5), zone-6 at south-west (Z6), and zone-7 at west (Z7). The obtained parameters were temperature 21.5±5.0 ºC, pH 8.2±0.6, dissolved oxygen (DO) 5.9±1.0 mg/L, biological oxygen demand (BOD) 23.9±5.7 mg/L, NH3-N 2.5±0.3 mg/L, NO2-N 1.9±0.3 mg/L, NO3-N 1.2±0.3 mg/L, PO4-P 1.9±0.3 mg/L, SiO4 3.2±0.1 mg/L, Chlorophyll-a (Chl-a) 88.2±10.8 µg/L, and salinity 3.2±1.0 g/L. Principal component analysis showed that agricultural drainage water was the key factor influencing the water quality characteristics of Burullus Lake. Water quality index (WQI) varied between “Bad” to “Medium”, suggesting that the lake wasn’t suitable for irrigation and fish growth; however, it was appropriate for some aquatic life. A MIKE21 model was developed to provide a recommendation scenario that could be used to enhance the water quality of Burullus Lake. By improving the water quality of precise drains (namely drains 7 and 8), the WQI at Z4 and Z6 modified from “Bad” to “Medium”. The period required to achieve this self-purification was 5 months.

Water Quality Enhancement in Ponds Using Baffles, Burullus in Egypt as a Case Study

This study investigated the simulation of hydrodynamics water quality in waste stabilization ponds (WSPs) after using baffles. The major functions performed by baffles are to reduce hydraulic short-circuiting and to provide a submerged surface, which can encourage the growth of attached biomass. Attached biomass growing on the surface of the baffles could increase the total mass of organisms in the pond, thus improve the treatment efficiency and therefore reduce the eutrophication rate in the pond such as NH3-N, NO3-N &amp;PO4-P. In this research, mathematical model (MIKE21) developed by (DHI), was formulated to simulate water quality parameter. The study applied on Burullus Lake, which is the second largest northern lake in Egypt, which belongs to high eutrophic lake type and suffers from several problems. Results showed that there is a significant variance between the rate of values without and after making baffles. The findings indicated that the percentage removal of NH3-N, NO3-N &amp;PO4-P are (51.8, 43.7 &amp;40.1%) respectively in the case of no overlap between baffles, to be (83.4, 94.3 &amp; 89.6%) in the case of overlap ratio 0.95 at the high temperature. This result suggests that the overlap between baffles is more efficient to reduce the eutrophic rate in the water. In conclusion, waste ponds can be improved easily and economically to be more efficient by making baffles.

Study of Convert Waste Stabilization Pond Geometry to Treated Wastewater Efficiency, (El- Burullus Lake, Egypt) As a Case Study

The simulation of hydrodynamics water quality in ponds is a developing tool that worth studying in order to understand their internal processes and interactions. Pond design involves several physical, hydrological, geometrical, biological and dynamic variables to provide high hydrodynamic efficiency and maximum substrate utilization rates. Computational fluid dynamic modelling (CFD) allows the combination of these factors to predict the behavior of ponds by using different configurations. In this research mathematical model developed by Danish Hydraulic Institute (DHI), was formulated to simulate WQ parameter. This model was calibrated and used to simulate a scenario to improve study reach water quality in polluted lakes. The study applied on El-Burullus Lake, which is the second largest northern lake in Egypt which belongs to high eutrophic lake type and suffers from several problems. The model was run at steady and variable state with raw wastewater to study the real effect of the polluted drains, which discharge high amount of polluted wastewater into the El-Burullus Lake and know the lake situation after make baffles scenario. The major functions performed by baffles are to reduce hydraulic short-circuiting and to provide a submerged surface which can encourage the growth of attached biomass. Attached biomass growing on the surface of the baffles could increase the total mass of organisms in the pond and thus improve the treatment efficiency and therefore reduce the eutrophication rate in the pond such as (NH3-N, PO4-P and NO3-N). Results showed that there are a significant variance between the rate of NH3-N, PO4-P and NO3-N before and after make baffles, and the overlap between baffles (L=0.50 baffle) is more efficient than no overlap. In conclusion, waste ponds and be improved easily and economically to be more efficient by making baffles in the lake which can increase the water velocity, avoided the dead zones area and reduce the eutrophic concentration.

Forecasting future changes in Manzala Lake surface area by considering variations in land use and land cover using remote sensing approach

This study assesses the changes in surface area of Manzala Lake, the largest coastal lake in Egypt, with respect to changes in land use and land cover based on a multi-temporal classification process. A regression model is provided to predict the temporal changes in the different detected classes and to assess the sustainability of the lake waterbody. Remote sensing is an effective method for detecting the impact of anthropogenic activities on the surface area of a lagoon such as Manzala Lake. The techniques used in this study include unsupervised classification, Mahalanobis distance supervised classification, minimum distance supervised classification, maximum likelihood supervised classification, and normalized difference water index. Data extracted from satellite images are used to predict the future temporal change in each class, using a statistical regression model and considering calibration, validation, and prediction phases. It was found that the maximum likelihood classification technique has the highest overall accuracy of 93.33%. This technique is selected to observe the changes in the surface area of the lake for the period from 1984 to 2015. Study results show that the waterbody surface area of the lake declined by 46% and the area of floating vegetation, islands, and land agriculture increased by 153.52, 42.86, and 42.35% respectively during the study period. Linear regression model prediction indicates that the waterbody surface area of the lake will decrease by 25.24% during the period from 2015 to 2030, which reflects the negative impact of human activities on lake sustainability represented by a severe reduction of the waterbody area.

Impact assessment of some heavy metals on tilapia fish, Oreochromis niloticus, in Burullus Lake, Egypt

BackgroundBurullus Lake has received a great attention because of its environmental and economic importance for being a significant source of fish production in Egypt. It is subjected to many of environmental changes due to the huge amount of discharges originated from different sources as well as many human activities. The Nile tilapia (Oreochromis niloticus) is an abundant sedentary fish present in the most Egyptian lakes, Nile River, and ponds. The study was designed to evaluate some metal pollution in Burullus Lake.ResultsThe values of heavy metals (Mn, Zn, Fe, Ni, Cu, and Pb) were measured in lake water and muscles of O. niloticus fish during winter and summer 2014. Water samples were collected from six sampling sites, while fish samples were collected from the three sectors (eastern, middle, and western) of the lake. The mean values of heavy metals (Mn, Zn, Fe, Ni, Cu, and Pb) in surface water of Burullus Lake during winter and summer for the year 2014 were 1.09, 10.50, 29.38, 6.87, 2.05, and 5.98 μg/L, respectively, whereas the annual means of heavy metals (Mn, Zn, Fe, Ni, Cu, and Pb) in the muscles of O. niloticus fish were 0.68, 4.70, 10.62, 0.52, 0.39, and 0.46 μg/g wet wt., respectively.ConclusionsIn lake water, Mn was the lowest concentration of the six sampling sites, while Fe was the highest concentration, whereas in fish muscles, Cu recorded the lowest concentration of the three sectors, while Fe was the highest concentration. The southern part of Burullus Lake had the highest heavy metal values as it influenced by the discharge of massive amounts of domestic sewage as well as agricultural and industrial effluents. The accumulation of heavy metals in fish muscles of the three sectors showed different patterns. Generally, the values of metals in the fish muscles were accepted by the international legislation limits and are safe for human consumption.

Efficient callus induction and plant regeneration of Lemna gibba strain 5503

In spite of the fact that Lemna gibba has an excellent potential in genetic transformation, only one strain has been transformed because of the limitation of available strains that have been optimized to regenerate efficiently in tissue culture. An axenic clone of the new strain of L. gibba was obtained from an industrial waste water lake in Egypt. The international ID 5503 was given to this new strain. 2,4-dichlorophenoxyacetic acid (2,4-D) concentration, light and frond orientation on media were examined to induce callus. Dorsal side up of the fronds was essential for callus induction. Low concentrations of 2,4-D (1-2 mg L-1) did not induce any visible callus while high concentrations (6-8 mg L-1) produced high frequency of callus induction (61-70% for light treatments and 50-65% for dark treatments). Light incubation treatments were generally superior in the frequency of callus induction especially with higher concentrations of 2,4-D (5-8 mg L-1). MS medium without cytokinins or supplemented with benzyladenine (BA) (1 mg L-1) or zeatin riboside (1 and 2 mg L-1) were examined to regenerate fronds from callus. Callus of light incubation treatments was superior to that of dark incubation treatments in regeneration with MS medium without cytokinin. Callus of dark incubation treatments was superior in regeneration with MS medium supplemented with cytokinins. One mg L-1 BA with the dark-derived treatment 6 mg L-1 2,4-D and 1 mg L-1 zeatin riboside with the dark-derived treatment 8 mg L-1 2,4-D determined highest regeneration frequency (80% each). Efficient callus induction (up to 80%) and regeneration (up to 90%) protocols were developed for the first time with the new L. gibba strain 5503. This new strain is the third L. gibba genotype that has been tested for callus induction and plant regeneration.