Benthic macrophyte communities in the Ghar El Melh lagoon (North Tunisia)

This work deals with the biodiversity and distribution of benthic macrophytes in the Ghar El Melh lagoon, a Mediterranean coastal lagoon located in the North of Tunisia. An inventory was made of the benthic flora and submerged macrophyte communities were mapped during two successive campaigns (the summer of 1999 and the winter of 2000). The following 24 macrophyte species were identified: seven red algae, two brown algae, 11 green algae, and four marine angiosperms. The results were compared with available data from the literature. Ruppia cirrhosa is the most dominant species. It is found in all lagoon parts, except in the west sector.Ruppia beds are usually associated withCladophora forming heterogeneous communities. During summerRuppia cirrhosa shows a large distribution, covering an area of ca. 21.4 km², with dense, extensive beds covering 80–100%. In winter, severalCladophora species have a very large distribution as well, covering nearly an area of 28.5 km² with an average cover of 46%. The green algaeCaulerpa prolifera is confined to the eastern part of the lagoon which is mainly affected by seawater. In comparison with previous situations, many transformations were observed in biodiversity and spatial distribution of the dominant communities. Thus,Cymodocea nodosa andZostera beds, which dominated in the 1970s, were replaced byZostera andCaulerpa prolifera in the 1980s and are currently succeeded byRuppia cirrhosa andCladophora. Restoration of the Ghar El Melh lagoon will enable an increase in the exchange with the open sea and the circulation of water, in particular in the confined zones. This should considerably improve the water quality and would positively influence the phytobenthic communities.     

Ammonia removal from compost leachate using zeolite. II. A study using continuous flow packed columns

Bench-scale packed zeolite columns were set up and operated to investigate the continuous removal of ammonium ions from compost leachate. The effects of hydraulic retention time (HRT), and particle size of the zeolite on the ammonia adsorption capacity were studied. For both the coarse particle and the powdered zeolite columns, higher ammonia removal efficiencies were achieved with longer HRT (i.e., lower influent flow rate) tests. At the same HRT, ammonia removal efficiencies from tests with powdered zeolite were generally 20% higher than tests with the coarse particle zeolite. A HRT of 6 hours was found appropriate for efficient ammonia removal, and an operating capacity of 1.31 mg N/g zeolite was obtained. Over 98% of the ammonia input from the influent was consistently removed for over 5 bed volumes (BV) of compost leachate flowing through the zeolite column. Zeolite proved to have a great potential as a medium for ammonia removal in treating composting leachate.     

Indicators for Chemicals: Sources,impacts and policy performance (5 pp)

Background Different types of indicators have been developed to describe the impact of chemicals on society and environment. Due to the high number of substances and their different types of use, most of these indicators are directed to specific areas of interest – regarding workplace safety, environmental health or consumer health. They address a specific subset of chemicals and can be used for monitoring enterprise-specific, national or international management measures. Main Features A survey of existing indicators for chemicals has shown that indicators already exist for a remarkable number of problem fields. As soon as the release and the environmental fate of chemicals are taken into account, the complexity of the approaches increases considerably. The distinction between indicators for drivers, pressures, state, impacts and responses, as proposed by the European Environmental Agency, supports the identification of proper indicators for a specific type of problem. Discussion and Conclusions. No single indicator exists which is able to cover the whole range of chemicals and their applications. Several indicator approaches cover at least a subset of the most relevant substances. If they are intended to be used for European monitoring, robust data must be provided by EU Member States. Chemicals in enterprises (ancillary inputs as well as process chemicals) are an important element of in-plant material flow management – in terms of occupational safety and health as well as environmental protection. Existing indicators for hazardous chemicals can be a valuable tool for process and product refinement regarding hazardous chemicals, especially for enterprises. Outlook Indicators for production and impact of chemicals, as well as policy performance indicators, are essential elements in order to monitor the management of chemicals. They have to be established for the national and for the EU level.     

Oxygen deficit determinations for a major river in eastern Hong Kong, China

Determination of oxygen deficit in the Hong Kong Shing-Mun River was based on the oxygen uptake by water, algal respiration and river sediment and the oxygen supplied to the river by surface reaeration and algal photosynthesis. A systematic study was conducted to examine the effect of water temperature, flow velocity and water depth on both the oxygen demands and the oxygen supplies. The oxygen budget of a water column in a selected section of the river was modeled. The results of the oxygen budget analysis showed that when water temperature was around 10 degrees C (the lowest temperature in the river), no deficit was observed. When water temperature was 10 degrees C to 20 degrees C, a small oxygen deficit appeared, especially in the deeper water. At the highest water temperature (30 degrees C), the oxygen deficit was maximal, -6.84 g O2/m2/day, in the night-time during the Spring tide period.     

A comparative investigation on the biosorption of lead by filamentous fungal biomass

The removal of lead from aqueous solutions by adsorption on filamentous fungal biomass was studied. Batch biosorption experiments were performed to screen a series of selected fungal strains for effective lead removal at different metal and biomass concentrations. Biosorption of the Pb²⁺ ions was strongly affected by pH. The fungal biomass exhibited the highest lead adsorption capacity at pH 6. Isotherms for the biosorption of lead on fungal biomass were developed and the equilibrium data fitted well to the Langmuir isotherm model. At pH 6, the maximum lead biosorption capacity of Mucor rouxii estimated with the Langmuir model was 769 mg/g dry biomass, significantly higher than that of most microorganisms. Biomass of Mucor rouxii showed specific selectivity for Pb²⁺ over other metals ions such as Zn²⁺. Ni²⁺ and Cu²⁺. This fungal strain may be applied to develop potentially cost-effective biosorbent for removing lead from effluents. The technique of scanning electron microscopy coupled with X-ray dispersion analysis shows that Pb²⁺ has exchanged with K⁺ and Ca²⁺ on the cell wall of Mucor rouxii, thereby suggesting ion exchange as one of the dominant mechanisms of metal biosorption for this fungal strain.     

Optimization of fuel briquette production from cassava peels,plantain peels and corn cobs

Journal of Material Cycles and Waste Management - Mechanical properties enable to handle storage and transport of fuel briquette. Binder is key element of these mechanical properties. Biobinder is...     

Assessing differences in macrofaunal assemblages as a factor of sieve mesh size,distance between samples,and time of sampling

With increasing cascading effects of climate change on the marine environment, as well as pollution and anthropogenic utilization of the seafloor, there is increasing interest in tracking changes to benthic communities. Macrofaunal surveys are traditionally conducted as part of pre-incident environmental assessment studies and post-incident monitoring studies when there is a potential impact to the seafloor. These surveys usually characterize the structure and/or spatiotemporal distribution of macrofaunal assemblages collected with sediment cores; however, many different sampling protocols have been used. An assessment of the comparability of past and current survey methods was in need to facilitate future surveys and comparisons. This was the aim of the present study, conducted off the Oregon coast in waters 25–35 m deep. Our results show that the use of a sieve with a 1.0-mm mesh size gives results for community structure comparable to results obtained from a 0.5-mm mesh size, which allows reliable comparisons of recent and past spatiotemporal surveys of macroinfauna. In addition to our primary objective of comparing methods, we also found interacting effects of seasons and depths of collection. Seasonal differences (summer and fall) were seen in infaunal assemblages in the wave-induced sediment motion zone but not deeper. Thus, studies where wave-induced sediment motion can structure the benthic communities, especially during the winter months, should consider this effect when making temporal comparisons. In addition, some macrofauna taxa-like polychaetes and amphipods show high interannual variabilities, so spatiotemporal studies should make sure to cover several years before drawing any conclusions.     

Investigation of the available technologies and their feasibility for the conversion of food waste into fish feed in Hong Kong

Food waste is the largest constituent of municipal solid waste in Hong Kong, but food waste recycling is still in its infancy. With the imminent saturation of all landfill sites by 2020, multiple technologies are needed to boost up the food waste recycling rate in Hong Kong. Conversion of food waste into animal feeds is prevalent in Japan, South Korea, and Taiwan, treating over 40 % of their recycled food waste. This direction is worth exploring in Hong Kong once concerns over food safety are resolved. Fortunately, while feeding food waste to pigs and chickens poses threats to public health, feeding it to fish is considered low risk. In order to examine the feasibility of converting food waste into fish feed in Hong Kong, this paper investigates the market demand, technical viability, feed quality, regulatory hurdles, and potential contribution. The results show that a significant amount of food waste can be recycled by converting it into fish feed due to the enormous demand from feed factories in mainland China. Two conversion technologies, heat drying and black soldier fly bioconversion, are studied extensively. Black soldier fly bioconversion is preferable because the end-product, insect powder, is anticipated to gain import approval from mainland China. The authors suggest further research efforts to speed up its application for food waste recycling in urban cities.     

Biomineralization markers during early shell formation in the European abalone <Emphasis Type="Italic">Haliotis tuberculata</Emphasis>, Linnaeus

Larval shell formation was investigated in the European abalone Haliotis tuberculata. Stages of mineralization as well as enzymatic and endocrine biomarkers were monitored throughout larval development, from hatching to post-larval stages. Polarized light microscopy and infrared spectroscopy analyses revealed the presence of crystallized calcium carbonate arranged in aragonite polymorphs from the late trochophore stage. A correlation between the main steps of shell formation and enzymatic activities of alkaline phosphatase and carbonic anhydrase was seen. The variations of these biologic activities were related to the onset of mineralization, the rapid shell growth, and the switch from larval to juvenile shell following metamorphosis. Furthermore, a strong increase in the level of calcitonin gene-related molecules was measured in post-larvae, suggesting that endocrine control takes place after metamorphosis. The changes measured for the three biomineralization markers together with mineralogical analysis allowed us to correlate physiologic mechanisms with early steps of abalone shell formation.