Distribution and Statistical Analysis of Leachable and Total Heavy Metals in the Sediments of the Suez Gulf

The concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pd and Zn) in the labile and total fractions of muddy and sandy sediment samples collected from twelve sites in Suez Gulf during April 1999 were studied to evaluate the pollution status of the Suez Gulf. The enrichment factors (EF) for each element were calculated. There are extremely high concentrations of Cd, Ni, Pb and slightly concentration of Cr and Cu in both muddy and sandy sediments. The concentration of Zn was moderately high and can be considered as seriously contaminate Metal pollution index (MPI) shows high values ranged between 46 to 156 and 40 to 232 for both sandy and muddy sediments, respectively. Concentrations of heavy metals were normalized against iron for total fraction in both of sandy and muddy sediments. Principal component analysis (PCA) was studied on the data matrix obtained and represented three-factor model explaining 92.22% for labile and 88.82% for total fractions of muddy sediment. The main source of contamination is the offshore oil fields and industrial wastes. This is largely a result of ineffective and inefficient operation equipment, illegal discharge of dirty ballast water from tankers and lack of supervision and prosecution of offenders.     

A study of heavy metals and their fate in the composting of tannery sludge

Tannery waste is categorized as toxic and hazardous in Malaysia due to its high content of Cr (in excess of 500 mg/kg) and other heavy metals. Heavy metals, when in high enough concentrations, have the potential to be both phytotoxic and zootoxic. Heavy metals are found as contaminants in tannery sludge. This investigation aimed to identify the fate of chromium, cadmium, copper, lead, and zinc concentrations in tannery sludge throughout a 50-day composting cycle. The results of this study showed a general increase in the removal of Cr, Cd, Pb, and to a much smaller extent Zn and Cu, manifested by a decrease in their overall concentrations within the solid fraction of the final product (the decreases were likely the result of leaching). Furthermore, in using a sequential extraction method for sludge composting at different phases of treatment, a large proportion of the heavy metals were found to be associated to the residual fraction (70-80%) and fractions more resistant to extraction, X-NaOH, X-EDTA, X-HNO3 (12-29%). Less than 2% of the metals were bound to bioavailable fractions X-(KNO3+H2O).     

Biogenic sulphide plays a major role on the riboflavin-mediated decolourisation of azo dyes under sulphate-reducing conditions

The effect of high concentrations of sulphate on the reductive decolourisation of different azo dyes by anaerobic sludge was studied in batch cultures. Sludge cultures were pre-incubated under sulphate-reducing conditions prior addition of dyes. Little or no effects of sulphate (5-10 g sulphate l(-1)) on the rate of decolourisation of Reactive Orange 14 (RO14), Direct Blue 53 (DB53) and Direct Blue 71 (DB71) were observed when no external redox mediator was provided. However, an increase in sulphate concentration, in the presence of riboflavin (20 microM), enhanced the decolourisation of all dyes. The first-rate constant of decolourisation (k) was increased up to 2-, 3.6- and 2-fold for RO14, DB53 and DB71, respectively, by supplying high sulphate concentrations, compared to the controls lacking sulphate, in the presence of the redox mediator. Sulphate reduction did not take place during the course of azo reductions, but was only evident before dye addition and after complete decolourisation, suggesting azo dyes reduction out-competed sulphate reduction for the available reducing equivalents. The experimental data suggest that reduction of azo dyes by riboflavin, which had been reduced by biogenic sulphide, was the major mechanism implicated during decolourisations, which was corroborated by abiotic incubations. Riboflavin greatly accelerated the abiotic reduction of RO14, so that the k value was increased up to 44-fold compared to the control lacking riboflavin.     

Sucrose amendment enhances phytoaccumulation of the herbicide atrazine in Arabidopsis thaliana

Growth in the presence of sucrose was shown to confer to Arabidopsis thaliana (thale cress or mustard weed) seedlings, under conditions of in vitro culture, a high level of tolerance to the herbicide atrazine and to other photosynthesis inhibitors. This tolerance was associated with root-to-shoot transfer and accumulation of atrazine in shoots, which resulted in significant decrease of herbicide levels in the growth medium. In soil microcosms, application of exogenous sucrose was found to confer tolerance and capacity to accumulate atrazine in Arabidopsis thaliana plants grown on atrazine-contaminated soil, and resulted in enhanced decontamination of the soil. Application of sucrose to plants grown on herbicide-polluted soil, which increases plant tolerance and xenobiotic absorption, thus appears to be potentially useful for phytoremediation.     

Freight transport and non-driving work duties as predictors of falling asleep at the wheel in urban areas of Crete

BACKGROUND: This study investigated the impact of subjective reports of drowsy driving and non-driving duties on the falling asleep responses and road crash involvement of professional drivers in Crete. An attempt was also made to elucidate other driving parameters, such as freight transportation, which could be potential predictors of risky driving, after controlling for lifestyle patterns. METHOD: A sample of 317 professional drivers was studied through personal interviews. The interview questionnaire included items about sleep and fatigue as contributing factors to falling asleep probability and crash risk. In addition, the drivers reported the type of freight they carried in their last trip, as well as practices such as smoking and alcohol consumption. RESULTS: The first logistic regression analysis showed that the most significant predictors of falling asleep at the wheel were transportation of fruits/vegetables and livestock, non-driving hours of work, insufficient hours of sleep, and smoking. The second logistic regression analysis revealed all the previous items as powerful factors of crash probability, including the transportation of express freight and freezer. IMPACT: The findings of the current study are discussed as they pertain to directions for future studies and for the development of fatigue countermeasures.     

Use of cement dust in the manufacture of vitrified sewer pipes

Waste by-pass cement dust was added in different percentages ranging from 2% to 10% to a standard mix for sewer pipes manufacture, as a substitute for expensive feldspar. It was found that a mix consisting of 45% kaolin, 36% ball clay, 9% grog and 10% by-pass dust and fired at a temperature of 1300 degrees C for 4 h yielded samples that meet the standards. It was possible to reach a water absorption of 4%, a modulus of rupture of 7.8 MPa and a resistance to acids and alkalis conforming with standard values. A test pipe was fabricated by vacuum extrusion using the suggested composition and was found to withstand a hydraulic pressure of 14 MPa for one minute without the appearance of any cracks.     

Element mobility during metasomatism of granitic rocks in the Saint-Chély d'Apcher area (Lozère,France)

This paper summarises the behaviour of major and trace elements during hydrothermal alteration processes in the Vareilles albite deposit, Saint-Chély d' Apcher area (Lozère, France). Sampling focused mainly on fine- to medium-grained two-mica granite facies surrounding albitite veins in two open pits. The primary chemical variability inherent in sampling parent rock and analytical uncertainties can seriously affect element mobility calculations. Here we present a simple model that allows to discriminate between magmatic and alteration effects and to make a proper evaluation of the chemical changes that have caused the alteration. For this reason, a range of unaltered granites and albitites were sampled to evaluate the degree of parent rock heterogeneity. Duplicate measurements were performed by epithermal neutron activation analysis (ENAA) to obtain a reliable mean concentration for trace elements and to evaluate results reproducibility. ENAA measurements are completed by analysis of major elements by inductively coupled plasma-mass spectrometry (ICP-MS). The enrichment or depletion of an element during alteration, relative to its concentration in fresh parent rock, can be calculated on the basis of the assumed immobility of some elements during the process. In this study, we have assumed Ta as immobile element on the basis for his inert behaviour. The distinct differences in chemical change between altered and unaltered granite suggest the need to consider alteration event as an important parameter in evaluating granitic rocks for nuclear waste disposal.     

Quinoa value chain,adoption, and market assessment in Morocco

Environmental Science and Pollution Research - Agriculture faces many challenges such as climate change, droughts, and salinity, which requires urgent interventions for fast adaptation and...     

Presence of heavy metals in drinking water resources of Iran: a systematic review and meta-analysis

Environmental Science and Pollution Research - Water quality is one of the most important indices for public health especially for drinking water consumptions. This study was conducted to survey...     

A critical review of state-of-the-art electrocoagulation technique applied to COD-rich industrial wastewaters

Environmental Science and Pollution Research - Electrocoagulation (EC) is one of the emerging technologies in groundwater and wastewater treatment as it combines the benefits of coagulation,...