Particulate matter concentration levels during intense haze event in an urban environment

This study assessed concentration levels of particulate matter (PM) in the ambient environment of Ilorin metropolis, Nigeria, during haze episodes. Meteorological data (wind speed and direction, rainfall data, sunshine data, relative humidity and temperature) were obtained. Aerocet 531S particle counter (MetOne Instruments, USA) was used to measure four mass concentration ranges of PM (PM_1.0, PM_2.5, PM₁₀ and the total suspended particles (TSP)) in 10 locations taking into consideration land use patterns. Surfer® version 8 (Golden Software LLC, USA) was used to model the spatial variation of particulate matter concentration levels using kriging interpolation griding method. Human exposure assessment was done using the total respiratory deposition dose (TRDD) estimates and statutory limit breach (SLB) approaches. The appearance of dominating weak southern atmospheric wind flow was observed as wind speed ranged from 0 to 6.811 m/s while solar radiation periods ranged from 0.3 to 3.5 h/day. The relative humidity of the metropolis ranged between 28 and 57%, while daily temperature was 15 to 36 °C. Highest concentration levels of PM measured were 73.4, 562.7, 7066.3 and 9907.8 μg/m³ for PM_1.0, PM_2.5, PM₁₀ and TSP, respectively. Very strong negative correlations existed between the PM concentration levels and microclimatic parameters. Spatial variation of the concentration level as modelled using Surfer® version 8 indicated that particulate concentration level increases from south to north. Concentration levels of PM for the 24-h averaging period were generally above the 24-h threshold limit value set by the regulatory agencies for all the locations.     

Relationships between aquatic invertebrate communities,water-level fluctuations and different habitats in a subtropical lake

In lakes, the littoral habitat and its invertebrate communities are often exposed to water-level fluctuations. We examined the effects of seasonal changes on water level, substrata availability and benthic fauna in the littoral zone of Peri Lake, a shallow lake that has experienced a strong reduction in water level due to changes in rainfall. In this study, we also examined whether the abundance and composition of aquatic invertebrates differed among the four substrata. Our main objective was to assess the effect of seasonal changes on water level and benthic invertebrates inhabiting the different types of substrata. Benthic invertebrates were sampled four different substrata (Schoenoplectus californicus, sand and stones, allochthonous leaf litter, and macrophyte stands), and we also measured meteorological, physical and chemical variables. We found that complex habitats, such as allochthonous leaf litter and aquatic macrophyte, stand to be colonised by a larger number of macroinvertebrates because they provide more habitats or potential niches for colonisation by different species. In addition, we observed that during periods of low water level, the presence of substrata in the littoral zone decreased, as did the associated biota. Therefore, our results suggest that water level changes have a major functional impact on the littoral zone of the lake, and can affect substratum availability, which also impacts invertebrate communities.     

Water management and aquatic ecosystem services of a tropical reservoir (Itaparica,São Francisco,Brazil)

Reservoirs have a wide variety of uses that have led to frequent conflicts over ecological conservation and contamination, especially as land management has intensified. Oligotrophication must be implemented in numerous tropical reservoirs that experience advanced eutrophication to maintain aquatic ecosystem functions. To quantify impacts on ecosystem functions and to develop an adaptive management policy, multiple studies have been conducted on the Itaparica Reservoir, São Francisco River, in the semi-arid north-eastern region of Brazil. Here, we add to that existing body of knowledge through investigating how nutrient accumulation is affected by water exchange between the main river flow and Icó-Mandantes Bay. Operational water-level fluctuations in the reservoir create large desiccated littoral areas that release high amounts of nutrients when they are rewetted. In particular, water-level variation promotes proliferation of Egeria densa, a noxious weed, thus elevating trophic levels of the Itaparica Reservoir and Icó-Mandantes Bay. Analysis with a P efficiency model determined 25 μg P L^?1 to be the critical concentration and further indicated that the critical load in both bodies of water have been exceeded. Moreover, intensive fish aquaculture using net cages has led to further overtaxing of the reservoir. We conclude that an effective ecological reservoir management policy must involve oligotrophication, harvesting of noxious water weeds for use as soil amendment in agriculture or biogas production, “blue” aquaculture, and limiting hydroelectric power production based on current water availability.     

Enhanced Interfacial Adhesion and Characterisation of Recycled Natural Fibre-Filled Biodegradable Green Composites

The structural, thermal, mechanical, and biodegradable properties of composite materials made from polylactide (PLA) and agricultural residues (arrowroot (Maranta arundinacea) fibre, AF) were evaluated. Melt blended glycidyl methacrylate-grafted polylactide (PLA-g-GMA) and coupling agent-treated arrowroot fibre (TAF) formed the PLA-g-GMA/TAF composite, which had better properties than the PLA/AF composite. The water resistance of the PLA-g-GMA/TAF composite was greater than that of the PLA/AF composite; the release of PLA in water from the PLA/AF and PLA-g-GMA/TAF composites indicated good biological activity. The PLA-g-GMA/TAF material had better mechanical properties than PLA/AF. This behaviour was attributed to better compatibility between the grafted polymer and TAF. The results indicated that the T_g of PLA was increased by the addition of fibre, which may have improved the heat resistance of PLA. Furthermore, the mass losses following burial in soil compost indicated that both materials were biodegradable, especially at high levels of AF or TAF substitution.     

Systemic design for sustainability

How can we restore the ecological balance of our planet? The present article is aimed at contributing a structural framework for such a restoration. In the quest for ecological recovery, cybernetic–systemic approaches are in demand. They specialize in coping with complexity and offer new, transdisciplinary and non-reductionist ways of system design for renewing sustainability. This contribution uses a proven model from organizational cybernetics—the viable system model—as a frame for sustainable development. The model specifies how the viability of any human or social system can be achieved by means of clearly defined organizational structures. In accord with the logic of recursive organization inherent in the model, a proposal for a structural design aimed at enabling ecological recovery is formulated. That design includes all organizational levels of recursion, from individual to world. The implications of such a novel approach are far-reaching, and the impact powerful.     

Deployment of parabolic trough concentrated solar power plants in North Africa – a case study for Libya

The study addresses the potential of using concentrated solar power plants (CSPs) as a sustainable alternative of clean energy generation in the Mediterranean region and, in particular, in its North Africa shore. This location presents attractive conditions for the installation of CSPs, in particular high solar irradiation, good manpower concentration, and proximity and availability of water resources for condenser cooling. Energetic, exergetic, and economic analyses were conducted taking into consideration a particular type of CSPs - the parabolic trough concentrated solar power plant, which incorporates the most proven technology and it is already used in Southern Europe (Spain). In addition, the study considered the impact of project financing and incentives on the cost of energy. The combination of higher values for performance and potentially lower levelized cost of electricity (LCE) for the North Africa Mediterranean Rim than the South of Spain region can yield a very favorable return for the invested capital. Tripoli compared to Almeria presented superior performance and potentially lower LCE values ($0.18/kWh versus $0.22/kWh). This is significant, even when it is taken into consideration the fact that the plant in Tripoli, despite a relatively modest capacity factor of 34%, has a large gross power output of 173,886 MWhe. In addition, the implementation at the Tripoli location of a plant similar to the Anadsol plant has a slight advantage (2–3%) in terms of overall efficiency.     

A climate-change vulnerability and adaptation assessment for Brazil's protected areas

Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km²) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km²), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future.     

Adsorption/desorption of arsenite and arsenate on chitosan and nanochitosan

Equilibrium sorption studies of anionic species of arsenite, As(III) ions and arsenate As(V) ions onto two biosorbents, namely, chitosan and nanochitosan, have been investigated and compared. The results and trends in the sorption behavior are novel, and we have observed during the sorption process of the As(III) and As(V) on chitosan, a slow process of desorption occurred after an initial maximum adsorption capacity was achieved, before reaching a final but lower equilibrium adsorption capacity. The same desorption trend, however, is not observed on nanochitosan. The gradual desorption of As(III) and As(V) in the equilibrium sorption on chitosan is attributed to the different fractions of the dissociated forms of arsenic on the adsorbent surface and in solution and the extent of protonation of chitosan with the changing of solution pH during sorption. The change of solution pH during the sorption of arsenite ions on chitosan was also influenced by the interaction between the buffering effect of the arsenite species in the aqueous medium and the physical properties of chitosan. The final equilibrium adsorption capacity of chitosan for As(III) and As(V) was found to be around 500 and 8000 μg/g, respectively, whereas the capacities on nanochitosan are 6100 and 13,000 μg/g, respectively.

     

Overcoming barriers to sustainability by combining conceptual,visual, and networking systems

Sustainability challenges rarely align with the conventional boundaries of our disciplines, institutions and means of communication. To address these challenges amid real-world complexity, we need to think holistically and collaborate across disciplines. In this paper, we synthesise three themes: (1) more integrated conceptual frameworks; (2) digital visual communication which provides fluid expression of complex ideas and perceptions; and (3) online networks which can empower sustainability initiatives and communicate them across social and institutional barriers at a global scale. Each of these tools can help to overcome persistent barriers to sustainability. When used together, they provide a strategic basis for the design of digital collaboration platforms for addressing sustainability challenges. Using design thinking, we developed a Synergy Map which identifies relationships among a number of barriers to sustainability and conceptual and digital tools which help to address them. The Map identifies the potential for synthesising these tools into effective digital artefacts. We provide several examples and identify characteristics of particular value for overcoming barriers to sustainability. Combining new theoretical developments in sustainability sciences with recent advances in communication and networking technologies offers substantial potential for advancing sustainability on multiple fronts.