Potential for internal loading by phosphorus based on sequential extraction of surficial sediment in a shallow Egyptian Lake

The fractionation of phosphorus (P) in shallow Lake Maryout surficial sediments was investigated in order to understand its potential availability in relation to the eutrophication status of this lake. The rank order of P fractions was NaOH-P > HCl-P > NH₄Cl-P > BD-P. The metal oxide-bound P (NaOH-P) averaged 43% in this hypereutrophic lake and would be potentially available under low oxygen conditions. The highly available, loosely sorbed P (NH₄Cl-P) represented 20% of the sedimentary inorganic P on average, while the reductant P (BD-P) averaged 15% and is also considered highly available under low oxygen conditions. The less available calcium-bound P (HCl-P) represented 22% of sedimentary inorganic P. Lake Maryout exhibits high potential for release of P from sediment in forms available to algae, which is undesirable for eutrophication control. The range of potentially available P in tested sediments was 1,541 to 3,990 mg/kg (ppm), a very high quantity capable of supporting algal blooms independent of external loading.     

Enhancing the performance of data-driven models for monthly reservoir evaporation prediction

Environmental Science and Pollution Research - The accuracy level for reservoir evaporation prediction is an important issue for decision making in the water resources field. The traditional...     

The front basitarsal brush in Pachycondyla apicalis and its role in hydrocarbon circulation

Summary. Worker postpharyngeal gland (PPG) chemistry of Pachycondyla apicalis constitutes a blend of hydrocarbons including alkanes, alkenes, and alkadienes, with 5,9-pentacosadiene, 5,9-heptacosadiene and 5,9-nonacosadiene as the major products as well as fatty acids. There is a large congruency between the PPG and cuticular hydrocarbons, however the latter had higher proportion of tricosane and pentacosane, but only traces of fatty acids. These ants have a well-developed cuticular hair brush on the front legs that they frequently pass through the mouth while grooming. Since these brushes have higher amounts of hydrocarbons than either the middle or hind legs, we hypothesized that they are involved in hydrocarbon circulation. We assessed the role of the front basitarsal brush in hydrocarbon circulation by isolating them from the buccal cavity, either by restraining the front legs or by blocking the mouth with glue. In both experiments, preventing contacts between the basitarsal brushes and the mouth for 24 hrs resulted in a considerable increase in hydrocarbon amounts in the brushes with a parallel decrease in the PPG. When the ants were kept alive for an additional 24 hrs after their legs were freed, hydrocarbon amounts in both the PPG and the front legs returned to normal. Analyses of crop content revealed the same hydrocarbons profile as in the PPG, but their amounts were very variable and there were no differences in amounts between the treatment and the control. We assume that part of the PPG hydrocarbons are cleared via the alimentary canal. Grooming behavior of ants restrained for 24 hrs and then freed was followed for four hours thereafter. There was a significant increase in total grooming during the first third and fourth hour, but not during the second. Grooming involving the front legs-mouth, and front legs-antennae, and the front and hind legs was especially intensive during the first hour. Grooming involving the hind legs - body was more intensive in the treated ants during the third hour following their release. We conclude that the front basitarsal brush is a site of hydrocarbon accumulation and that the PPG receives frequent charging during self-grooming.     

Tetrabromobisphenol-A, hexabromocyclododecane and its degradation products in UK human milk: relationship to external exposure

Tetrabromobisphenol-A (TBBP-A), hexabromocyclododecane (HBCD) and its degradation products were determined in 34 human milk samples from Birmingham, UK. TBBP-A was detected in 36% of samples (average=0.06 ng g(-1) lw), with HBCDs detected in all samples (average ΣHBCDs=5.95 ng g(-1) lw). α-HBCD comprised 62-95% ΣHBCDs while β- and γ-HBCD constituted 2-18% and 3-33% respectively. Enantioselective enrichment of (-)-α-HBCD (average enantiomer fraction=0.29) was observed indicating potential enantioselectivity associated with HBCD absorption, metabolism and/or excretion. The degradation products pentabromocyclododecenes (average=0.04 ng g(-1) lw; n=9) and tetrabromocyclododecadienes (average=0.15 ng g(-1) lw; n=25) were detected for the first time in human tissues. Average exposures of a nursing infant to ΣHBCDs and TBBP-A (35 and 1 ng kg(-1) bw day(-1) respectively) via breast milk exceeded upper-bound dietary intakes of both UK adults and toddlers. Using a simple pharmacokinetic model, intakes of UK adults via inhalation, diet and dust ingestion were converted to predicted body burdens. Predictions compared well with those observed for HBCDs but observed body burdens of TBBP-A exceeded predictions. This may indicate the human half-life of TBBP-A is greater than observed previously, that intakes may be underestimated, or that concentrations reported here reflect recent elevated episodic exposure.     

Biomonitoring study of heavy metals in biota and sediments in the South Eastern coast of Mediterranean sea, Egypt

Concentrations of Cd, Cu, Co, Zn, Mn and Fe were determined in biota and sediment samples collected from the Eastern Harbour and El-Mex Bay in the Mediterranean Sea, Egypt. The levels of Cu, Co, Zn, Mn and Fe in the macroalgae, Ulva lactuca, Enteromorpha compressa (green algae) and Jania rubens (red algae), recorded high concentrations except for Cd. Moreover, Fe was the most predominant metal in the seaweed. The two species of bivalves, Donax trunculus and Paphia textile, showed different amounts of metals in their tissue. The abundance of heavy metal concentrations in the mussel samples was found in the order Fe> Zn> Mn> Cu> Co> Cd and Fe> Zn> Mn> Cu> Cd> Co, respectively for the two species. The metals concentrations were generally higher compared with the previous studies in mussels from the same area. The levels of metals accumulated in the investigated fish samples, Saurida undosquamis, Siganus rivulatus, Lithognathus mormyrus and Sphyraena sphyraena, were higher than those of Marmara Sea (Turkey), for Co and Cd and lower for Cu, Zn, Mn and Fe. El-Mex Bay having the highest metals concentration in sediments as their order of abundance were Fe> Zn> Mn> Cu> Cd> Co. Nevertheless, a high variability in the metal levels occurs among the studied algae and biota and also between the investigated Harbour. A significant correlations (p < 0.05) were found for each of Zn and Fe in P. textile and of Co in D. trunculus relative to their concentrations in surficial sediments.     

Contents of heavy metals in marine seaweeds from the Egyptian coast of the Red Sea

Seaweeds belonging to 14 different genera of Chlorophyta, Phaeophyta, and Rhodophyta were analysed to determine the levels of heavy metals in two areas of the Egyptian Red Sea coast. Among the trace metals analysed, Mn and Zn showed the highest mass concentrations in the surface sea waters of the two studied areas. However, algae obtained from the Suez area had higher concentrations of the investigated heavy metals than those collect in the Mars Alam area. Nevertheless, a high variability of the metal levels occurs among the studied algae and also between the investigated areas. Moreover, Zn was the most abundant metal in the seaweeds of the Suez area, while Pb was predominant in the Mars Alam area in red and brown algae. Liagora spp. had the highest average concentration factor of Zn in Suez (29 161-fold), while the average concentration factor in Enteromorpha spp. at Mars Alam was 20 091-fold. The highest Metal Pollution Index (MPI) value was recorded in Liagora spp. (22.0) at Suez. This represents a 4.6-fold higher value than that recorded in Liagora spp. at Mars Alam. Among green, brown, and red algae in Suez, the highest values of MPI were recorded in Cladophora spp. and Halimeda spp. (18.2 and 18.3), Padina spp. (16.2), and Liagora spp. (22.1), respectively; while at Mars Alam, the highest values of MPI were recorded in Cladophora spp. (6.6), Padina spp. (3.4) and Liagora spp. (4.8), respectively.     

Development of a waste management protocol based on assessment of knowledge and practice of healthcare personnel in surgical departments

Background:Good healthcare waste management in a hospital depends on a dedicated waste management team, good administration, careful planning, sound organization, underpinning legislation, adequate financing, and full participation by trained staff. Hence, waste management protocols must be convenient and sensible.Aim of study:To assess the knowledge and practice related to waste management among doctors, nurses, and housekeepers in the surgical departments at Al-Mansoura University Hospital, and to design and validate a waste management protocol for the health team in these settings.Subjects and methods:This cross-sectional study was carried out in the eight surgical departments at Al-Mansoura University Hospital. All health care personnel and their assistants were included: 38 doctors, 106 nurses, and 56 housekeepers. Two groups of jury were included for experts’ opinions validation of the developed protocol, one from academia (30 members) and the other from service providers (30 members). Data were collected using a self-administered knowledge questionnaire for nurses and doctors, and an interview questionnaire for housekeepers. Observation checklists were used for assessment of performance. The researchers developed the first draft of the waste management protocol according to the results of the analysis of the data collected in the assessment phase. Then, the protocol was presented to the jury group for validation, and then was implemented.Results:Only 27.4% of the nurses, 32.1% of the housekeepers, and 36.8% of the doctors had satisfactory knowledge. Concerning practice, 18.9% of the nurses, 7.1% of the housekeepers, and none of the doctors had adequate practice. Nurses’ knowledge score had a statistically significant weak positive correlation with the attendance of training courses (r = 0.23, p < 0.05). Validation of the developed protocol was done, and the percent of agreement ranged between 60.0% and 96.7% for the service group, and 60.0% and 90.0% for the academia group.Conclusion and recommendations:The majority of the doctors, nurses, and housekeepers have unsatisfactory knowledge and inadequate practice related to health care waste management. The knowledge among nurses is positively affected by attendance of training programs. Based on the findings, a protocol for healthcare waste management was developed and validated. It is recommended to implement the developed waste management protocol for the surgical departments in the designed hospital, with establishment of waste management audits.     

Contents of heavy metals in marine algae from Egyptian Red Sea coast

Seaweeds belonging to 14 different genera of Chlorophyta, Phaeophyta and Rhodophyta were analyzed to determine the levels of heavy metals in two areas of the Egyptian Red Sea coast. Among the trace metals analyzed, Mn and Zn showed the highest mass concentrations in the surface seawaters of the two studied areas. However, algae obtained from Suez area had the highest concentrations of the investigated heavy metals than those collected from Mars Alam area. Nevertheless, a high variability of the metal levels occurs among the studied algae and also between the investigated areas. Moreover, Zn was the most abundant metal in the seaweeds of the Suez area, while Pb was predominant in Mars Alam area in red and brown algae. L. farinosa had the highest average concentration factor of Zn in Suez (29161 fold), while it was 20091 fold in E. intestinalis at Mars Alam. The highest value of metal pollution index (MPI) was recoded in L. farinosa (22.0) at Suez. It represents 4.6 fold of that value recorded in L. farinosa at Mars Alam. Among green, brown and red algae in Suez, the highest values of MPI were recorded in Cladophora (mixed sub-species) and H. comuto (18.2 and 18.3), P. pavonia (16.2) and L. farinosa (22.1), respectively; while at Mars Alam, they were recorded in Cladophora (mixed sub-species) (6.6), P. pavonia (3.4) and L. farinosa (4.8), respectively.     

Specific activity and hazards of granite samples collected from the Eastern Desert of Egypt

Fifty granitic rock samples were collected from different plutons in the central part of the Eastern Desert of Egypt and were analyzed for specific concentrations of (238)U, (232)Th and (40)K radionuclei. The measurements were carried out using a high performance and stability Nomad Plus spectroscopy system attached to a 1.7 keV (FWHM) HPGe detector. The spectra were analyzed using the direct gamma counting comparison method as well as the traditional absolute efficiency curve method. The highest average value of (238)U concentration (1184 Bq kg(-1)) was observed at EI Misikat region whereas the highest average values of (40)K and (232)Th concentration (2301.8 and 162.5 Bq kg(-1) respectively), were detected at Gabal Homret Waggat area. The radium equivalent activity (Ra(eq)), the absorbed dose rate (D), the external hazard index (H(ex)) and the annual gonadal dose equivalent were also calculated and compared to the international recommended values. Radon exhalation rate from the rock samples were measured using the activated charcoal canister method. The average value of radon exhalation varies from 0.052 to 0.69 Bq m(-2) h(-1) and depends on the specific concentration of uranium.