Carbon footprint analysis for increasing water supply and sanitation in South Africa: a case study

This study investigates the environmental burdens due to the provision of potable water and sanitation in the eThekwini Municipality (Durban), South Africa. This was achieved by employing LCA studies for the individual parts of the urban water system (impoundment, water treatment, distribution, collection, sewage treatment and water recycling). Based on the results of the individual LCAs a base case was constructed.For the provision of potable water and sanitation to new customers, which have not been previously served, two different scenarios (200 000 new customers in an urban environment with waterborne sewage and in a peri-urban environment with on-site sanitation) and three different options (maximising use of existing assets, recycling water and building new infrastructure) were considered and analysed. With regard to the impact scores calculated for both scenarios (urban and peri-urban), the recycling of water is followed by maximising the use of existing assets as the most environmentally friendly options. The construction of new infrastructure carries a higher environmental burden and the use of bottled water for drinking (an additional scenario) carries the highest environmental burden.     

Quantification of greenhouse gas emissions from waste management processes for municipalities--a comparative review focusing on Africa

The amount of greenhouse gases (GHG) emitted due to waste management in the cities of developing countries is predicted to rise considerably in the near future; however, these countries have a series of problems in accounting and reporting these gases. Some of these problems are related to the status quo of waste management in the developing world and some to the lack of a coherent framework for accounting and reporting of greenhouse gases from waste at municipal level. This review summarizes and compares GHG emissions from individual waste management processes which make up a municipal waste management system, with an emphasis on developing countries and, in particular, Africa. It should be seen as a first step towards developing a more holistic GHG accounting model for municipalities. The comparison between these emissions from developed and developing countries at process level, reveals that there is agreement on the magnitude of the emissions expected from each process (generation of waste, collection and transport, disposal and recycling). The highest GHG savings are achieved through recycling, and these savings would be even higher in developing countries which rely on coal for energy production (e.g. South Africa, India and China) and where non-motorized collection and transport is used. The highest emissions are due to the methane released by dumpsites and landfills, and these emissions are predicted to increase significantly, unless more of the methane is captured and either flared or used for energy generation. The clean development mechanism (CDM) projects implemented in the developing world have made some progress in this field; however, African countries lag behind.     

Feasibility assessment of electrocoagulation towards a new sustainable wastewater treatment

BACKGROUND, AIM AND SCOPE: Electrocoagulation (EC) may be a potential answer to environmental problems dealing with water reuse and rational waste management. The aim of this research was to assess the feasibility of EC-process for industrial contaminated effluents from copper production, taking into consideration technical and economical factors. EC-technology claims to offer efficient removal rates for most types of wastewater impurities at low power consumption and without adding any precipitating agents. MATERIALS AND METHODS: Real wastewater from Saraka stream with high concentrations of heavy metals was provided by RTB-BOR, a Serbian copper mining and smelting complex. Runs were performed on a 10 l EC-reactor using aluminum plates as sacrificial electrodes and powered by a 40 A supply unit. Results concerning key factors like pH, conductivity and power consumption were measured in real time. Analysis of dissolved metal concentrations before and after treatment were carried out via ICP-OES and confirmed by an independent test via AAS. RESULTS: Several aspects were taken into account, including current density, conductivity, interfacial resistivity and reactor settings throughout the runs, in order to analyze all possible factors playing a role in neutralization and metal removal in real industrial wastewater. DISCUSSION: Electrode configurations and their effects on energy demand were discussed and exemplified based on fundamentals of colloidal and physical chemistry. CONCLUSIONS: Based on experimental data and since no precipitating agents were applied, the EC-process proved to be not only feasible and environmentally-friendly, but also a cost-effective technology RECOMMENDATIONS AND PERSPECTIVES: The EC-technology provides strategic guidelines for further research and development of sustainable water management processes. However, additional test series concerning continuous operation must be still performed in order to get this concept ready for future large-scale applications.     

Isopropyl (Z9)-hexadecenoate as a male attractant pheromone from the sternal gland of the rove beetle Aleochara curtala (Coleoptera: Staphylinidae)

Summary. In the rove beetle Aleochara curtula, a male specific sternal gland is described. Isopropyl (Z9)-hexadecenoate has been identified by GC/MS of surface and sternal gland extracts as a male specific compound. Its emission in the air was demonstrated by closed-loopstripping-analyses. In field experiments, conspecific males and females were attracted by the odor of carrion, caged males from laboratory cultures, and by the synthetic ester. Isopropyl (Z9)-hexadecenoate or live males, combined with fresh carrion attract more beetles than a fresh carcass alone. Isopropyl hexadecanoate as a minor compound was not attractive. The term “aggregation” pheromone and the ecological significance of attracting females to a fresh carcass allowing early copulation and egg-deposition are discussed. Received 20 August 1998; accepted 15 January 1999.     

Bioassay zur Bestimmung von TCDD-Toxizitätsäquivalenten (TEQ) von Umweltproben und Reststoffen

Polychlorinated aromatic hydrocarbons (HAH) like 2,3,7,8-tetrachloro-p-dioxin (TCDD) elicit a multitude of toxic and biological effects. A common trait of these substances is their affinity for a cytosolic receptor protein and the subsequent induction of the synthesis of several gene products, including cytochrome P450 1A1 (CYP 1A1). In this publication we present a bioassay to determine the induction of CYP 1A1 as a sum parameter for the total toxic potential of critical halogenated compounds in complex environmental matrices. In order to eliminate compounds like polycyclic aromatic hydrocarbons (PAH) and naturally occurring substances which might interfere with the bioassay we developed a simple cleanup procedure. TEQ values derived from bioassay are in good agreement with those obtained from chemical analysis. This bioassay in combination with the simplified “single column” clean up represents a cost and time effective alternative to chemical analysis for the screening of large numbers of environmental matrices.     

Microbial diversity in the marine sponge Aplysina cavernicola (formerly Verongia cavernicola) analyzed by fluorescence in situ hybridization (FISH)

We have employed electronmicroscopical methods (SEM, TEM) to document the microbial community associated with the marine sponge Aplysina cavernicola (formerly Verongia cavernicola, class Demospongiae). Five dominant bacterial types were identified, three of which resemble the morphotypes originally described by Vacelet (1975). One bacterial type possesses morphological properties that are characteristic of the genus Planctomyces. In addition, morphologically uniform bacteria which reside inside the nuclei of host cells were observed. Using in situ hybridization with fluorescently labelled rRNA probes directed against known bacterial groups, the phylogenetic affiliation of the mesohyl bacteria was assessed. It could be shown that the vast majority of mesohyl bacteria belongs to the domain Bacteria with a low GC content. Among the Bacteria, the delta-Proteobacteria were most abundant, followed by the gamma-Proteobacteria and representatives of the Bacteroides cluster. Clusters of Gram-positive bacteria with a high GC content were also found consistently in low amounts. No hybridization signal was obtained with probes specific to the domain Archaea, to the alpha- and beta-Proteobacteria and to the Cytophaga/Flavobacterium cluster. This study describes for the first time the application of the “top-to-bottom approach” using 16S rRNA probes and in situ hybridization to assess the microbial diversity in Aplysina sponges. Received: 18 December 1998 / Accepted: 12 March 1999     

Bioindikation mit Wanderfalken

Goal and Scope

The Stockholm convention bans 12 prominent persistent organic pollutants (POPs), and the pertinent global monitoring programme recommends birds’ eggs as bio-indicators for the terrestrial food web. As top predators, Peregrine falcons are uniquely suited indicators because of their accumulating power for persistent and lipophilic compounds. On the other hand, the Peregrine falcon as a sentinel species was closer to extinction than other birds of prey. Only unremitting efforts of private omithologists throughout the past four decades in conjunction with the timely banning of organochlorine pesticides like DDT succeeded in saving the Peregrine population of Baden-Wueriternberg from extinction, in contrast to the Peregrine falcons of other German states or other European countries.

Methods

See vd Trenck et al. (2006).

Results and Conclusions

New results confirm the findings of the past long-term bio-monitoring. The main pollutants are PCBs (ca. 20 μg/g) and pp′-DDE (ca. 11 μg/g), the latter contributing >96% of all organochlorine pesticide residues (all concentrations on a dry matter basis). Both substances have followed a slightly increasing trend since 2004. The sum of the polychlorinated diphenyl ethers (PBDE) has fluctuated strongly in the past four years, and in 2006 amounted to 0.6 μg/g (mean without outliers), just as the mercury contamination of the eggs. PCB-156 as the main dioxin-like PCB followed with an average concentration of 0.35 μg/g. Only 10 out of 23 eggs analysed contained hexabromocyclododecane (HBCD) in measurable concentrations; the mean concentration of these eggs was 0.024 μg/g. Tetrabromobisphenol A (TBBA) was detected in all egg samples with a mean of 0.004 μg/g. Due to the many and diverse effects exerted by PCBs; the assessment of this group of compounds, with the aid of European and German regulations for food, proves to be a complex matter, which is currently in a state of flux. There is no doubt, however, that the mean pollution of the Peregrine eggs with toxic dioxin equivalents (WHO TEQ) has reached the no observed adverse effect level (NOAEL) known for chickens and osprey chicks, and the most polluted eggs exceed this threshold considerably. The toxic profile of PBDEs is similar to that of PCBs. They are known to promote tumour growth, to interfere with the thyroid hormone system resulting in toxicity for the neuronal development, to suppress the immune system, and to trigger stress reactions. Tests with highly purified BDE-47 have ruled out dioxin-like effects via Ah-receptor binding for this congener and such effects are therefore very unlikely for the whole class of compounds. At the present time, quantitative criteria for the assessment of the risk posed by PBDEs are not sufficiently reliable, and less so for HBCD and TBBA.

Recommendations and Perspectives

It is necessary to continue the bio-monitoring of POPs and similar pollutants in the terrestrial food web and to establish NOAELs as quantitative criteria for their assessment. Possible sources of dioxin-like PCBs and PCDD/Fs are to be pinpointed, and abatement measures are to be considered where background concentrations are significantly exceeded.     

Laboratory and field comparison of measurements obtained using the available diffusive samplers for ozone and nitrogen dioxide in ambient air

This study presents an evaluation of the extent of differences between measurements performed by O(3) and NO(2) diffusive samplers and by the reference methods for diffusive samplers commercially available. The tests were performed in an exposure chamber under extreme conditions of controlling factors and under field conditions. For NO(2), the results of the laboratory experiments showed that most of the diffusive samplers were affected by extreme exposure conditions. The agreement between the samplers and the reference method was better for the field tests than for the laboratory ones. The estimate of the uptake rate for the exposure conditions using a model equation improved the agreement between the diffusive samplers and the reference methods. The agreement between O(3) measured by the diffusive samplers and by the reference method was satisfactory for 1-week exposure. For 8-hour exposures, the diffusive samplers with high uptake rates quantified better the O(3) concentration than the samplers with low uptake rates. As for NO(2), the results of the O(3) field tests were in better agreement with the reference method than the ones of the laboratory tests. The field tests showed that the majority of diffusive samplers fulfils the 25% uncertainty requirement of the NO(2) European Directive and the 30% uncertainty requirement of the O(3) European Directive for 1-week exposure.     

Marine debris contamination along undeveloped tropical beaches from northeast Brazil

We hypothesize that floating debris leaving polluted coastal bays accumulate on nearby pristine beaches. We examined composition, quantities and distribution of marine debris along approximately 150 km of relatively undeveloped, tropical beaches in Costa do Dendê (Bahia, Brazil). The study site is located south of Salvador City, the largest urban settlement from NE Brazil. Strong spatial variations were observed. Plastics accounted for 76% of the sampled items, followed by styrofoam (14%). Small plastic fragments resultant from the breakdown of larger items are ubiquitous all over the area. Because the dominant littoral drift in Bahia is southward, average beach debris densities (9.1 items/m) along Costa do Dendê were threefold higher than densities previously observed north of Salvador City. River-dominated and stable beaches had higher debris quantities than unstable, erosional beaches. Areas immediately south of the major regional embayments (Camamu and Todos os Santos) were the preferential accumulation sites, indicating that rivers draining populous areas are the major source of debris to the study site. Our results provide baseline information for future assessments. Management actions should focus on input prevention at the hydrographic basin level rather than on cleaning services on beaches.