Trophic state and potential productivity assessment for Qaroun Lake using spatial techniques.

Qaroun Lake is one of the most important Egyptian lakes which, recently, have been exposed to severe degradation in water quality and fish productivity. In this manuscript, Carlson's trophic state index (CTSI) was used to evaluate the trophic state, while the trophometric index (TMI) was used to assess the potential productivity of Qaroun Lake. The present study is one of the initial attempts to investigate these indices in Qaroun Lake. To achieve this work, an integrated multidisciplinary approach was adopted integrating field investigation, geographic information system, and data analysis. CTSI combines three variables of water quality: chlorophyll-a (CHL-a), total phosphorus (TP), and transparency measured by Secchi disk depth (SDD). The result of overall CTSI showed the hypereutrophic state is represented by 62% and eutrophic state is represented by 38% of the total lake's area. Moreover, the calculated TMI indicated the average potential productivity value (PP) is 619 t. It can be concluded that the hypereutrophic is the dominant state in Qaroun Lake. The present study recommends the application of TMI model to evaluate and monitor the changes in Qaroun Lake's potential productivity in response to the changing environmental conditions and other biological pressures (e.g., Isopoda paraside).

Taxonomic and functional structure of macrobenthic invertebrate communities and their response to environmental variables along the subbranches of the Nile River (rayahs), Egypt.

Macrobenthic invertebrate communities serve as markers of anthropogenic stress in freshwater ecosystems. In this study, 17 sampling sites were selected from two Nile river subbranches (El-Rayah El-Behery and El-Rayah El-Nassery) and subjected to different anthropogenic influences to explore the ecological environment and characteristics of macrobenthos communities. Macrobenthos were studied using taxonomic diversity and biological trait analysis to investigate how human activity and variation in water quality affect their structure and function. A total of 37 taxa represented by 43,389 individuals were recognized. The communities are composed chiefly of Oligochaeta and aquatic insects. Multivariate statistical analyses found that the most influential environmental variables in the structural and functional community were sodium, dissolved oxygen, silicate, pH, calcium, and cadmium. At high levels of pollution, notably sewage and industrial pollution in the northern part of El-Rayah El-Behery, characteristics such as larger body size, detritus feeders, burrowers, and high tolerance to pollution predominated, whereas at low levels of pollution, features such as small body sizes, scraper and predator feeders, intolerant and fairly tolerant of pollution, and climber and swimmer mobility are predominant. The results confirm our prediction that the distribution of macroinvertebrate traits varies spatially in response to environmental changes. The diversity-based method distinguished impacted sewage and industrial sites from thermal effluent sites, while the trait-based approach illustrated an apparent variance between the ecological status of contaminated regions. Therefore, the biological features should be employed in addition to structural aspects for assessing the biodiversity of macroinvertebrate communities under environmental stressors.

New synthetic chitosan hybrids bearing some heterocyclic moieties with potential activity as anticancer and apoptosis inducers.

Wastes of the freshwater crayfish Procambarus clarkii were used as precursor for the extraction of chitin, which was deacetylation with alkali giving chitosan. Chitosan was transformed into the nanoparticles using sodium tripolyphosphate. Chitosan Cs and its nanoparticles CNP were characterized through FTIR, 1H NMR and surface morphology. Moreover, it was converted into some chitosan Schiff bases; CSB-1,2,3, containing different five membered heterocyclic moieties and also they were characterized. All of the synthesized compounds were evaluated against three cell lines, such as HepG-2, HCT-116 and MCF-7, whereas compounds CSB-2 and CSB-3 showed the highest cytotoxic activities. The higher activities for the latter compounds were confirmed through apoptosis studies (Caspase-3 and Bax/Bcl-2 ratio) against HePG-2 cells. Cell cycle analysis and apoptosis induction showed that compound CSB-2 induces apoptosis at pre G1 phase and cell growth arrest at G2/M phase.

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

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.