Total and Leachable Heavy Metals in Muddy and Sandy Sediments of Egyptian Coast Along Mediterranean Sea

The assessment of marine pollution due to metals was made for surficial sediments sampled from 20 sites along Mediterranean coast of Egypt. The samples were dried, acid digested and analyzed for leachable and total heavy metal contents (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) by flame atomic absorption spectrophotometer (air–acetylene) with deuterium background correction. Evaluation of the heavy metals pollution status was carried out using enrichment factors (EFs), the effect range-low (ERL) and the effect range-median (ERM). The study showed high concentrations of Cd, Co, Pb, Ni and moderate concentrations of Cr, Cu and Mn were contaminated in the sediments of studied sites. The results of Spearman correlation, factor and cluster analysis of the heavy metals analyzed in the collected sediment were discussed. The main source of contamination is the offshore oil field and industrial wastes, which arise due to the ineffective and inefficient operation equipments, illegal discharge and lack of supervision and prosecution of offenders.     

Effects of Spirulina platensis and Amphora coffeaeformis as dietary supplements on blood biochemical parameters,intestinal microbial population,and productive performance in broiler chickens

Environmental Science and Pollution Research - Spirulina platensis (Sp) or Amphora coffeaeformis (Am) are good candidates as an in-feed antibiotic substitute for broilers. This work was performed...     

Use of GIS and Moran’s I to support residential solid waste recycling in the city of Annaba,Algeria

Environmental Science and Pollution Research - Urban planners require an understanding of the composition as well as the spatial distribution of household solid waste (HSW) components to design...     

Aliphatic and polycyclic aromatic hydrocarbons in the surface sediments of the Mediterranean: assessment and source recognition of petroleum hydrocarbons

Coastal marine sediment samples were collected from ten sampling stations along the Egyptian Mediterranean coast in April 2010. All sediment samples were analyzed for aliphatic (C7 to C34) and polycyclic aromatic hydrocarbons (PAHs) as well as total organic carbon (TOC) contents and grain size analysis. Total aliphatic hydrocarbons ranged from 1621.82 to 9069.99 ng/g (dry weight), while aromatic hydrocarbons (16 PAHs) varied between 208.69 and 1020.02 ng/g with an average of 530.68?±?225.86 ng/g?dwt. Good correlations observed between certain PAH concentrations allowed to identify its origin. The average TOC percent was varied from 0.13 to 1.46 %. Principal component analysis was used to determine the sources of hydrocarbon pollutants in sediments of Mediterranean. Additionally, special PAHs compound ratios suggest the petrogenic origins.     

Assessment of arsenic immobilization in synthetically prepared cemented paste backfill specimens

Mine tailings coming from the exploitation of sulphide and/or gold deposits can contain significant amounts of arsenic (As), highly soluble in conditions of weathering. Open mine voids backfilling techniques are now widely practiced by modern mining companies to manage the tailings. The most common one is called cemented paste backfill (CPB), and consists of tailings mixed with low amounts of hydraulic binders (3-5%) and a high proportion of water (typically 25%). The CPB is transported through a pipe network, to be placed in the mine openings. CPB provides storage benefits and underground support during mining operations. Moreover, this technique could also enhance contaminant stabilization, by fixing the contaminants in the binder matrix. CPB composites artificially spiked with As were synthesized in laboratory, using two types of hydraulic binders: a Portland cement, and a mix of fly ash and Portland cement. After curing duration of 66 days, the CPB samples were subjected to several leaching tests in various experimental conditions in order to better understand and then predict the As geochemical behaviour within CPBs. The assessment of the As release indicates that this element is better stabilized in Portland cement-based matrices rather than fly ash-based matrices. The As mobility differs in these two matrices, mainly because of the different As-bearing minerals formed during hydration processes. However, the total As depletion does not exceed 5% at the end of the most aggressive leaching test, indicating that As is well immobilized in the two types of CPB.     

Influence of sampling sufficiency on biodiversity analysis of microperiphyton communities for marine bioassessment

Introduction  

With quick responses to environmental changes, easy sampling, relative immobility, increasing availability of easily used taxonomic references, and allowing standardization for temporal and spatial comparisons, the biodiversity measures of microperiphyton communities have widely been accepted as useful indicators to evaluate environmental stress and anthropogenic impact.     

Influence of Some Chelators on the Phytoextraction Ability of Sunflower (Helianthus annuus) for Nickel‐Contaminated Soil

Chelation and complexation of nickel were evaluated as practical ways to solubilize, detoxify, and enhance nickel accumulation by plants. Sunflower (Helianthus annuus) was selected as a potential nickel accumulator in two selected soils with different textures and nickel‐contamination levels. To enhance metal phytoextraction, ammonium nitrate and organic chelators (EDTA and citric acid) were added to soils in pots at rates of 0, 5, 10, and 20 mmol/kg. The pot experiments were run for eight weeks. The highest nickel uptake was obtained in plants grown on clayey soil, and the lowest uptake was observed in sandy soil. Citric acid was the most effective chelator of nickel metals that could enhance nickel accumulation in the sunflower shoots. The ammonium nitrate application showed a low effect on metal translocation into the sunflower shoots. © 2014 Wiley Periodicals, Inc.     

Bioreactor landfills: experimental and field results

Bioreactor landfills allow a more active landfill management that recognizes the biological, chemical and physical processes involved in a landfill environment. This paper presents the results of an experimental study carried out to determine the effect of solid waste size, leachate recirculation and nutrient balance on the rate of municipal solid waste (MSW) biodegradation. Higher rates of MSW biodegradation eventually cause a reduction of the contaminant life span of the landfill and decrease in the cost of long term monitoring. The study indicated that the smaller the size of the MSW the faster the biodegradation rate of the waste. In addition, the paper presents the results of leachate recirculation on solid waste biodegradation in a full-scale landfill site, which is located in Nepean, Ontario, Canada. The leachate was recirculated into the landfilled solid waste for 8 years through infiltration lagoons. Similar results to those obtained in the laboratory scale experiments were noted. The average pH of the leachate in the early stages of recirculation was on the acidic range of the pH scale, however, the pH value was in the range of 7-8 after 2 years of leachate recirculation. The concentration of chloride remained fairly constant at about 1000 mg/l during the leachate recirculation period. A decreasing trend of the organic load, measured as biological oxygen demand and chemical oxygen demand, was observed. Recovery of landfill air space was also noted because of the enhanced subsidence and decomposition of the solid waste.