Transforming open mining pits into fish farms: Moving towards sustainability

The legacy of mining activities has typically been land ‘returned to wildlife’, or, at some sites, degraded to such an extent that it is unsuitable for any alternate use. Progress towards sustainability is made when value is added in terms of the ecological, social and economic well‐being of the community. In keeping with the principles of sustainable development, the innovative use of flooded open pits and tailings impoundments as commercial, recreational or ornamental fish farms should be considered in some locations, as it could make a significant contribution to the social equity, economic vitality and environmental integrity of mining communities. This article highlights the growing significance of aquaculture and explores the benefits and barriers to transforming flooded pits and impoundments into aquaculture operations. Among other benefits, aquaculture may provide a much‐needed source of revenue, employment and, in some cases, food to communities impacted by mine closure. Further, aquaculture in a controlled closed environment may be more acceptable to critics of fish farming who are concerned about fish escapes and viral transmissions to wild populations. Despite the potential benefits, aquaculture in flooded pits and impoundments is not without its complications — it requires a site‐specific design approach that must consider issues ranging from metals uptake by fish, to the long‐term viability of the aquatic system as fish habitat, to the overall contribution of aquaculture to sustainability.     

Monitoring of water quality inflow and outflow of a farm in Italian Padana plain for rice cultivation: a case study of two years

Environmental Science and Pollution Research - Rice cultivation requires a large use of pesticides and nutrients to control weed proliferation and improve production. The water quality of four...     

Fe(III)–EDDS complex in Fenton and photo-Fenton processes: from the radical formation to the degradation of a target compound

The present work compares the efficiency of homogenous Fenton and photo-Fenton processes in the presence of Fe(III)–EDDS complex under different experimental conditions. 4-tert-Butylphenol (4-t-BP), which is one of the endocrine disrupting chemicals, was used as a model pollutant to investigate the Fenton and photo-Fenton application. The efficiency of homogenous photo-Fenton process was significantly much higher than homogenous Fenton process, which is due to the rapid formation of Fe²⁺ under UV irradiation of the iron complex and the photochemical formation of HO^? from the photolysis of the complex Fe(III)–EDDS. Through the degradation of 4-t-BP, the effect of Fe(III)–EDDS concentration, H₂O₂ concentration, pH, and oxygen was investigated in both processes. Such trend was also correlated with pH calculating the polychromatic Fe²⁺ quantum yield formation at pH 4.0, 6.0, and 8.6. The results showed that at high Fe(III)–EDDS and H₂O₂ concentrations, a negative effect was found. By the way, the Fenton process was found to be enhanced at basic pH. These results can be very useful for the use and optimization of such iron complex in water treatment process as function of different physico-chemical conditions.     

Collective work and resilience of complex systems

This article aims to describe the characteristics of collective working situations in complex systems – especially those in nuclear power plants – related to common forms of cooperation, in order to improve systems resilience. In addition, we will try to detail some aspects of collective working situations, emphasizing the differences between various forms of control. The similarities between work activities (multi-addressed messages, linkage to regulation, central and peripheral information) are nonetheless exposed. We conclude by proposing a contribution to support systems design, thus facilitating cooperation in teamwork activities.     

Qualitative and Quantitative Assessment of Hepatitis A Virus in Wastewaters in Tunisia

Hepatitis A causes substantial morbidity in both industrialized and non-industrialized countries and represents an important health problem in several southern Mediterranean countries. The objectives of the study were as follows: (a) to assess the occurrence of hepatitis A virus (HAV) in Tunisia through the monitoring of urban wastewaters collected at wastewater treatment plants (WTPs); (b) to characterize environmental strains; and (c) to estimate the viral load in raw and treated sewages, in order to evaluate the potential impact on superficial waters receiving discharges. A total of 150 raw and treated wastewaters were collected from three WTPs and analyzed by both qualitative (RT-PCR/nested) and quantitative (qRT-PCR) methods. Of these, 100 (66 %) were found to be positive for HAV by the qualitative assay: 68.3 % in influents and 64.7 % in effluents. The vast majority of HAV sequences belonged to sub-genotype IA, with 11 different strains detected found to be identical to clinical strains isolated from Tunisian patients with acute hepatitis. Five unique variants were also detected, not previously reported in clinical cases. Only two IB strains were found, confirming the rarity of this sub-genotype in this country. The results of the present study indicate a wide circulation of the pathogen in the population, most probably in the form of asymptomatic infections, a finding consistent with the classification of the country as having intermediate/high endemicity. Quantitative data showed high viral loads in influents (3.5E+05 genome copies/liter, mean value) as well as effluents (2.5E+05 genome copies/liter, mean value), suggesting that contaminated water could be a critical element in transmission.     

Humic acid in ice: Photo-enhanced conversion of nitrogen dioxide into nitrous acid

Laboratory studies on the heterogeneous conversion of nitrogen dioxide into nitrous acid on irradiated ice films containing humic acid are described. It was found that the presence of light in the visible range of the solar spectrum significantly enhances the rate of nitrous acid release from a humic acid doped ice film. This process might contribute to observed HONO production in snow, where the NO₂ is thought to originate from nitrate photolysis. Analysis of the experimental data based on the Langmuir Hinshelwood model framework allowed quantification of the observed dependencies of the nitrous acid production rate on nitrogen dioxide concentration. The observed dependencies on the humic acid concentration as well as on the irradiation intensity were used to estimate light-driven HONO fluxes for environmental snow covers.     

Method for automatic determination of soybean actual evapotranspiration under open top chambers (OTC) subjected to effects of water stress and air ozone concentration

The present study describes an operational method, based on the Katerji et al. (Eur J Agron 33:218-230, 2010) model, for determining the daily evapotranspiration (ET) for soybean inside open top chambers (OTCs). It includes two functions, calculated day par day, making it possible to separately take into account the effects of concentrations of air ozone and plant water stress. This last function was calibrated in function of the daily values of actual water reserve in the soil. The input variables of the method are (a) the diurnal values of global radiation and temperature, usually measured routinely in a standard weather station; (b) the daily values of the AOT40 index accumulated (accumulated ozone over a threshold of 40 ppb during daylight hours, when global radiation exceeds 50 Wm(-2)) determined inside the OTC; and (c) the actual water reserve in the soil, at the beginning of the trial. The ensemble of these input variables can be automatable; thus, the proposed method could be applied in routine. The ability of the method to take into account contrasting conditions of ozone air concentration and water stress was evaluated over three successive years, for 513 days, in ten crop growth cycles, excluding the days employed to calibrate the method. Tests were carried out in several chambers for each year and take into account the intra- and inter-year variability of ET measured inside the OTCs. On the daily scale, the slope of the linear regression between the ET measured by the soil water balance and that calculated by the proposed method, under different water conditions, are 0.98 and 1.05 for the filtered and unfiltered (or enriched) OTCs with root mean square error (RMSE) equal to 0.77 and 1.07 mm, respectively. On the seasonal scale, the mean difference between measured and calculated ET is equal to +5% and +11% for the filtered and unfiltered OTCs, respectively. The ability of the proposed method to estimate the daily and seasonal ET inside the OTCs is therefore satisfactory following inter- and intra-annual tests. Finally, suggestions about the applications of the proposed method for other species, different from soybean, were also discussed.     

A critical look at residential electricity conservation campaigns in a developing country environment

This paper analyses survey results of the effectiveness of information campaigns to promote energy efficiency among residential consumers in Brazil. The survey found that consumers have a relatively good knowledge of conservation measures to improve electricity usage. Nevertheless, other approaches are needed to promote energy conservation in the household sector.     

Conventional and fast pyrolysis of automobile shredder residues (ASR)

This work aims at comparing performance and product yields in conventional pyrolysis and fast pyrolysis of automotive shredded residues. In both processes, carbon conversion to gaseous and liquid products was more than 80%. Gas production was maximised in conventional pyrolysis (about 35% by weight of the initial ASR weight), while fast pyrolysis led to an oil yield higher than 55%. Higher heating values (HHV) of both conventional pyrolysis gas and fast pyrolysis oil increased from 8.8 to 25.07 MJ/Nm3 and from 28.8 and 36.27 MJ/kg with increasing pyrolysis temperature.     

Reducing mercury pollution from artisanal gold mining in Munhena,Mozambique

Artisanal small-scale mining (ASM) is responsible for over 90% of gold production in Mozambique. In 2005, a 15-day pilot training project was held in the village of Munhena, a gold mining community. This intervention aimed at raising awareness related to the environmental and health impacts of mercury amalgamation and introduced alternative practices to reduce mercury release and exposure. In 2007, a 9-day evaluation of the pilot campaign was accomplished and knowledge in regards to mining methods, and the ASM government–community operating relations in Munhena were updated. Miners in Munhena are organized in an association of over 3000 members, work on a 25 year Government granted 143 ha concession and generate a substantial income (producing over 5 kg of gold per month). There remain, however, serious barriers towards sustainable community development. ASM associated environmental and health costs are high, as mercury continues to be used and lost to the environment, and cyanide will be introduced soon. The Government of Mozambique has laid the foundation for supporting this sector; however, resources are limited, and thus restrict ability to fully address these issues. Importantly, malaria and HIV/AIDS are not diagnosed and/or treated effectively within the community, and basic necessities are absent. This paper concludes with recommendations focused on enhancing the ASM sector in Mozambique, and overcoming barriers to sustainability in the community of Munhena.