Toxicity of Hg, Cu and Zn on early developmental stages of the European clam (Ruditapes decussatus) with potential application in marine water quality assessment

The toxicity of mercury, zinc and copper on sperm viability, fertilisation and embryogenesis of Ruditapes decussatus was examined. Cu did not affect sperm viability at all the concentrations tested. Conversely, the Zn and Hg significantly (P?<?0.01) reduced sperm viability only at the highest concentration (respectively 512 and 256 μg/l). Cu caused a significant decrease (p?<?0.05) of less than 6% in the fertilisation rate at 128 μg/l and Zn of up to 13% at 64 μg/l. Hg significantly (p?<?0.01) inhibited fertilisation at concentrations as low as 32 μg/l. The median effective concentrations (EC50) reducing rates of embryogenesis by 50% were 21.1 μg Hg/l (0.1 μM), 46.3 μg Cu/l (0.72 μM) and 43.4 μg Zn/l. Therefore, Hg is up to seven times more toxic than Cu (on a molar basis). Ecotoxicity of mercury on larvae survival was also assessed in this work. Result showed a significant (p?<?0.05) reduction of survival after exposure to 4 and 12 μg/l of Hg. The fertilisation rate and embryogenesis were the most sensitive endpoints, although the latter is more advisable for routine assessment of seawater quality because of its greater sensibility.     

Development of the concept of spatial–temporal mask for testing effects of discharge from well-drilling activities on biological communities

This paper describes the use of Bayesian spatial models to develop the concept of a spatial–temporal mask for the purpose of identifying regions in which before and after drilling effects are most clearly defined and from which the consequences of exposure of macrofauna and meiofauna to the release of drilling discharges can be evaluated over time. To determine the effects of drilling fluids and drill-cuttings on the marine benthic community, it is essential to know not only where discharged materials ended up within the possible impact area, but also the chemical concentrations to which biota were exposed during and after drilling. Barium and light hydrocarbons were used as chemical tracers for water-based and non-aqueous-based fluids in a shallow water site in the Campos Basin, off the coast of Brazil. Since the site showed evidence of exposure to waste material from earlier drilling, the analysis needed to take into account the background concentrations of these compounds. Using the Bayesian models, concentrations at unsampled sites were predicted and regions altered and previously contaminated were identified.     

Use of microbial activity measurements for monitoring RBC biofilms

Fixed biomass technologies, such as rotating biological contactors or biodiscs, have been applied for wastewater depuration both in large and medium–small-sized agglomerations. Biofilm’s composition and microorganism activity are essential parameters for the successful operation and control of these systems. Biofilm’s thickness and total dry weight have been widely used for biofilm’s characterization but, actually, are not sufficient to describe biofilm activity. In fact, biofilm’s activity is not proportional to the quantity of fixed biomass, but increases with the thickness of biofilm up to a determined level called the “active thickness”. Above this level, the diffusion of nutrients through the film becomes a limiting factor. A stable, thin, and active biofilm thus offers numerous advantages in water and wastewater treatment. Different parameters have been used to evaluate biofilm’s activity. The specific oxygen uptake rate, INT-dehydrogenase activity, and the ratio active/total cells have been applied for that purpose. These methods are not only simple and rapid but also sensitive, precise, and representative. The results obtained confirm the potential of the microbial activity measurements studied for an accurate biofilm’s characterization and biomass activity estimation in fundamental research and for the practical operation and control of fixed biomass depuration systems.     

Organic speciation of atmospheric particles in Alvão Natural Park (Portugal)

PM₁₀ continental rural background aerosols were collected during a summer field campaign (August–September 2006) at Lamas de Ôlo in the upper zone of the Alvão Natural Park, a mountain region of northern Portugal. In addition to the determination of the carbonaceous content by a thermal–optical method, the organic speciation of aerosols was performed by gas chromatography–mass spectrometry in an effort to evaluate photo-oxidation products of biogenic volatile organic compounds and other markers for source characterization. The detailed analysis revealed relatively high concentrations of polyols and short-chain dicarboxylic, tricarboxylic, hydroxycarboxylic, and oxocarboxylic acids, many of which are thought to be indicators of secondary aerosol formation, accounting for about 70% of global chromatographically resolved mass. Major photo-oxidation products of α- and β-pinene have been detected. The tracers for the photo-oxidation of isoprene comprise two diastereoisomeric 2-methyltetrols, C₅-alkene triols, and 2-methylglyceric acid, which have only recently been elucidated. In addition, the occurrence of levoglucosan and other biomass combustion tracers indicates that the site was affected by wildfires. This source contributed to more than 80% of the organic carbon mass during a period of strong forest fire influence.     

Multiscale satellite and spatial information and analysis framework in support of a large-area forest monitoring and inventory update

Many countries undertake a national forest inventory to enable statistically valid monitoring in support of national and international reporting of forest conditions and change. Canada’s National Forest Inventory (NFI) program is designed to operate on a 10-year remeasurement cycle, with an interim report produced at the 5-year mid-point. The NFI is a sample-based inventory, with approximately 18,850 2 ×2-km photo plots across the country, distributed on a 20×20-km grid of sample points; these photo plots are the primary data source for the NFI. Capacity to provide annual monitoring information is required to keep policy and decision makers apprised of current forest conditions. In this study, we implemented a multistage monitoring framework and used a Moderate Resolution Imaging Spectroradiometer (MODIS) change product to successfully identify 78% of the changes in forest cover area that were captured with a Landsat change detection approach. Of the NFI photo plots that were identified by both the Landsat and MODIS approaches as having changes in forest cover, the proportion of change area within the plots was similar (R ²?=?0.78). Approximately 70% of the Landsat-derived change events occupied less than 40% of a single MODIS pixel, and more than 90% of the change events of this size were successfully detected with the MODIS product. Finally, MODIS estimates of the proportion of forest cover change at the NFI photo plot level were comparable to change estimates for the ecoregions as a whole (R ²?=?0.95). High-temporal, low-spatial resolution imagery such as MODIS, in combination with other remotely sensed data sources, can provide information on disturbance events within a national forest inventory remeasurement cycle, thereby satisfying the interim information needs of policy and decision makers as well as the requirements of national and international reporting commitments.     

Serial batch leaching procedure for characterization of coal fly ash

Although many leaching methods have been used for various purposes by research groups, industries, and regulators, there is still a need for a simple but comprehensive approach to leaching coal utilization by-products and other granular materials in order to estimate potential release of heavy metals when these materials are exposed to natural fluids. A serial batch characterization method has been developed at the National Energy Technology Laboratory that can be completed in 2–3 days to serve as a screening tool. The procedure provides an estimate of cumulative metals release under varying pH conditions, and leaching the sample at increasing liquid/solid ratios can indicate the rate at which this process will occur. This method was applied to eight fly ashes, adapted to the acidic or alkaline nature of the ash. The leachates were analyzed for 30 elements. The test was run in quadruplicate, and the relative standard deviation (RSD) was used as a measure of method reproducibility. RSD values are between 0.02 and 0.70, with the majority of the RSD values less than 0.3. The serial batch leaching procedure was developed as a simple, relatively quick, yet comprehensive method of estimating the risk of heavy metal release from fly ash when it is exposed to natural fluids, such as acid rain or groundwater. Tests on a random selection of coal fly ashes have shown it to be a reasonably precise method for estimating the availability and long-term release of cations from fly ash.     

Chemical-mineralogical characterisation of coarse recycled concrete aggregate

The construction industry is now putting greater emphasis than ever before on increasing recycling and promoting more sustainable waste management practices. In keeping with this approach, many sectors of the industry have actively sought to encourage the use of recycled concrete aggregate (RCA) as an alternative to primary aggregates in concrete production. The results of a laboratory experimental programme aimed at establishing chemical and mineralogical characteristics of coarse RCA and its likely influence on concrete performance are reported in this paper. Commercially produced coarse RCA and natural aggregates (16-4 mm size fraction) were tested. Results of X-ray fluorescence (XRF) analyses showed that original source of RCA had a negligible effect on the major elements and a comparable chemical composition between recycled and natural aggregates. X-ray diffraction (XRD) analyses results indicated the presence of calcite, portlandite and minor peaks of muscovite/illite in recycled aggregates, although they were directly proportioned to their original composition. The influence of 30%, 50%, and 100% coarse RCA on the chemical composition of equal design strength concrete has been established, and its suitability for use in a concrete application has been assessed. In this work, coarse RCA was used as a direct replacement for natural gravel in concrete production. Test results indicated that up to 30% coarse RCA had no effect on the main three oxides (SiO2, Al2O3 and CaO) of concrete, but thereafter there was a marginal decrease in SiO2 and increase in Al2O3 and CaO contents with increase in RCA content in the mix, reflecting the original constituent's composition.     

Pilot installation for the thermo-chemical characterisation of solid wastes

The increasing production and the large variety of wastes require operators of thermal treatment units to continuously adapt the installations or the functioning parameters to the different physical and chemical properties of the wastes. Usually, the treated waste is encountered in the form of heterogeneous mixtures. The classical tests such as thermogravimetry and calorimetric bomb operate component by component, separately. In addition to this, they can analyse only small quantities of waste at a time (a few grams). These common tests are necessary but insufficient in the global waste analysis in the view further thermal treatment. This paper presents an experimental installation, which was designed and built at the CNRS Science Division, Department of Industrial Methods, Compiègne University of Technology, France. It allows the determination of waste thermal and chemical properties by means of thermal treatment. Also, it is capable of continuously analysing significant quantities of waste (up to 50kg/h) as compared to the classical tests and it can work under various conditions: The installation reproduces the process conditions from incinerators or pyrolysis reactors. It also provides complete information on the kinetics of the waste thermal degradation and on the pollutant emissions. Using different mixtures of components present in the municipal solid waste and also in the reconstituted MSW samples, we defined a series of criteria for characterising waste behaviour during the stages of the main treatment process such as: feeding, devolatilisation/oxidation, advancement, solid residue evacuation, and pollutants emission.     

Assessment of medical wastes management practice: a case study of the northern part of Jordan

This study includes a survey of the procedures available, techniques, and methods of handling and disposing of medical waste at medium (between 100 and 200 beds) to large (over 200 beds) size healthcare facilities located in Irbid city (a major city in the northern part of Jordan). A total of 14 healthcare facilities, including four hospitals and 10 clinical laboratories, serving a total population of about 1.5 million, were surveyed during the course of this research. This study took into consideration both the quantity and quality of the generated wastes to determine generation rates and physical properties. Results of the survey showed that healthcare facilities in Irbid city have less appropriate practices when it comes to the handling, storage, and disposal of wastes generated in comparison to the developed world. There are no defined methods for handling and disposal of these wastes, starting from the personnel responsible for collection through those who transport the wastes to the disposal site. Moreover, there are no specific regulations or guidelines for segregation or classification of these wastes. This means that wastes are mixed, for example, wastes coming from the kitchen with those generated by different departments. Also, more importantly, none of the sites surveyed could provide estimated quantities of waste generated by each department, based upon the known variables within the departments. Average generation rates of total medical wastes in the hospitals were estimated to be 6.10 kg/patient/day (3.49 kg/bed/day), 5.62 kg/patient/day (3.14 kg/bed/day), and 4.02 kg/patient/day (1.88 kg/bed/day) for public, maternity, and private hospitals, respectively. For medical laboratories, rates were found to be in the range of 0.053-0.065 kg/test-day for governmental laboratories, and 0.034-0.102 kg/test-day for private laboratories. Although, based on the type of waste, domestic or general waste makes up a large proportion of the waste volume, so that if such waste is not mixed with patient derived waste, it can be easily handled. However, based on infections, it is important for healthcare staff to take precautions in handling sharps and pathological wastes, which comprises only about 26% of the total infectious wastes. Statistical analysis was conducted to develop mathematical models to aid in the prediction of waste quantities generated by the hospitals studied, or similar sites in the city that are not included in this study. In these models, the number of patients, number of beds, and hospital type were determined to be significant factors on waste generation. Such models provide decision makers with tools to better manage their medical waste, given the dynamic conditions of their healthcare facilities.     

Ignition and burning rates of segregated waste combustion in packed beds

Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.