Inactivation of <Emphasis Type="Italic">Escherichia coli</Emphasis> in fresh water with advanced oxidation processes based on the combination of O<Subscript>3</Subscript>, H<Subscript>2</Subscript>O<Subscript>2</Subscript>, and TiO<Subscript>2</Subscript>. Kinetic modeling

The purpose of this work was to study the efficiency of different treatments, based on the combination of O₃, H₂O₂, and TiO₂, on fresh surface water samples fortified with wild strains of Escherichia coli. Moreover, an exhaustive assessment of the influence of the different agents involved in the treatment has been carried out by kinetic modeling of E. coli inactivation results. The treatments studied were (i) ozonation (O₃), (ii) the peroxone system (O₃/0.04 mM H₂O₂), (iii) catalytic ozonation (O₃/1 g/L TiO₂), and (iv) a combined treatment of O₃/1 g/L TiO₂/0.04 mM H₂O₂. It was observed that the peroxone system achieved the highest levels of inactivation of E. coli, around 6.80 log after 10 min of contact time. Catalytic ozonation also obtained high levels of inactivation in a short period of time, reaching 6.22 log in 10 min. Both treatments, the peroxone system (O₃/H₂O₂) and catalytic ozonation (O₃/TiO₂), produced a higher inactivation rate of E. coli than ozonation (4.97 log after 10 min). While the combination of ozone with hydrogen peroxide or titanium dioxide thus produces an increase in the inactivation yield of E. coli regarding ozonation, the O₃/TiO₂/H₂O₂ combination did not enhance the inactivation results. The fitting of experimental values to the corresponding equations through non-linear regression techniques was carried out with Microsoft® Excel GInaFiT software. The inactivation results of E. coli did not respond to linear functions, and it was necessary to use mathematical models able to describe certain deviations in the bacterial inactivation processes. In this case, the inactivation results fit with mathematical models based on the hypothesis that the bacteria population is divided into two different subgroups with different degrees of resistance to treatments, for instance biphasic and biphasic with shoulder models.

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Insights into low fish mercury bioaccumulation in a mercury-contaminated reservoir, Guizhou, China

We examined Hg biogeochemistry in Baihua Reservoir, a system affected by industrial wastewater containing mercury (Hg). As expected, we found high levels of total Hg (THg, 664-7421 ng g(-1)) and monomethylmercury (MMHg, 3-21 ng g(-1)) in the surface sediments (0-10 cm). In the water column, both THg and MMHg showed strong vertical variations with higher concentrations in the anoxic layer (>4m) than in the oxic layer (0-4 m), which was most pronounced for the dissolved MMHg (p < 0.001). However, mercury levels in biota samples (mostly cyprinid fish) were one order of magnitude lower than common regulatory values (i.e. 0.3-0.5 mg kg(-1)) for human consumption. We identified three main reasons to explain the low fish Hg bioaccumulation: disconnection of the aquatic food web from the high MMHg zone, simple food web structures, and biodilution effect at the base of the food chain in this eutrophic reservoir.     

Solanum nigrum L. weed plants as a remediation tool for metalaxyl-polluted effluents and soils

In this work, the phytoremediation potential of metalaxyl, a commonly used persistent, mobile and leachy fungicide, by Solanum nigrum L. plants was studied. The study revealed that this plant species can be used as an excellent metalaxyl phytoremediation tool, thus providing a cost effective and environmentally friendly clean technology for the decontamination of sites and effluents. As it can be sowed directly in the remediation site, is able to complete its life cycle without suffering major stress. Because it accumulates high amounts of the fungicide in the aboveground tissues, enables its concentration and proper disposal by cutting off the corresponding plant part. The study also suggests that the tolerance to metalaxyl is due to a suitable antioxidant response comprising proline accumulation and guaiacol peroxidase and glutathione-S-transferase enhanced activities, that reduce oxidative damage to the plant organs.     

Characterization of municipal solid waste from the main landfills of Havana city

The city of Havana, the political, administrative and cultural centre of Cuba, is also the centre of many of the economic activities of the nation: industries, services, scientific research and tourism. All of these activities contribute to the generation of municipal solid waste (MSW), which also impact other Cuban cities. Inadequate handling of waste and the lack of appropriate and efficient solutions for its final disposal and treatment increase the risk and possibility of contamination. The main difficulty in the development of a system of management of MSW lies in the lack of knowledge of the chemical composition of the waste that is generated in the country as a whole, and especially in Havana, where solid waste management decisions are made. The present study characterizes MSW in Havana city during 2004. The Calle 100, Guanabacoa and Ocho Vías landfills were selected for physical-chemical characterization of MSW, as they are the three biggest landfills in the city. A total of 16 indicators were measured, and weather conditions were recorded. As a result, the necessary information regarding the physical-chemical composition of the MSW became available for the first time in Cuba. The information is essential for making decisions regarding the management of waste and constitutes a valuable contribution to the Study on Integrated Management Plan of MSW in Havana.     

Effects of different quinoid redox mediators on the removal of sulphide and nitrate via denitrification

The impact of different quinoid redox mediators on the simultaneous conversion of sulphide and nitrate in a denitrifying culture was evaluated. All quinones evaluated, including anthraquinone-2,6-disulphonate (AQDS), 2-hydroxy-1,4-naphthoquinone and 1,2-naphthoquinone-4-sulphonate (NQS) were reduced by sulphide under abiotic conditions. NQS showed the highest reduction rate by sulphide (132 μmol h⁻¹) and promoted the maximum rate of sulphide oxidation (87 μmol h⁻¹) by denitrifying sludge, which represents an increase of 44% compared to the control lacking quinones. The reduced form of AQDS (AH₂QDS) served as an electron donor for the microbial reduction of nitrite and N₂O, which represents the first demonstration of hydroquinones supporting the microbial reduction of denitrifying intermediates. The results taken as a whole suggest that some quinones may significantly increase the rate of removal of S and N under denitrifying conditions.     

Conservation Biology Framework for the Release of Wild-Born Orphaned Chimpanzees into the Conkouati Reserve, Congo

Abstract: Returning confiscated animals to their native habitats is desirable when it makes a positive contribution to the conservation of the species. Release of captive individuals is complex and controversial, however, particularly when risks are potentially high, as in the case of orphaned apes. We describe the decision-making process that led to the successive release of 20 wild-born orphan chimpanzees (    Pan troglodytes troglodytes ) into the Conkouati Reserve in the Republic of Congo. Recommendations of the Reintroduction Specialist Group of the World Conservation Union's Species Survival Commission were followed closely. The conservation status, ecology, and behavior of wild chimpanzees; the biological, social, economic and political context of the release site; and the health and genetic status of the candidates for release were all taken into account in the planning and execution of the project. Rigorous post-release monitoring of behavior and health allowed documentation of the outcome. The project was of benefit to the chimpanzees that were released but also brought broad benefits to the site through effective protection from poaching and deforestation, and direct and indirect benefits to local people. The genetic and behavioral diversity of chimpanzees require a variety of conservation strategies to reduce threats and maintain as many viable wild populations as possible.     

Organotropism of total mercury (THg) in Cichla pinima,ecological aspects and human consumption in fish from Amazon region,Brazil

Environmental Science and Pollution Research - Specimens of the Cichla pinima are of ecological and economic importance in the Amazon region and are a good bioindicator species of Hg...     

Emergency drills for agricultural drought response: a case study in Guatemala

Drills are an important element of disaster management, helping to increase preparedness and reduce the risk of real‐time failure. Yet, they are not applied systematically to slow‐onset disasters such as a drought, which causes damage that is not instantly apparent and thus does not solicit immediate action. This case study evaluates how drills inform institutional responses to slow‐onset disasters. It spotlights Guatemala, a country where drought has severe impacts on livelihoods and the food security of small farmers. By implementing part of the Ministry of Agriculture, Livestock and Food's institutional response plan for drought, it explores how drills can help to detect issues in emergency response and to foster an institutional focus on improvements in preparedness. The results reveal that drills alone do not trigger institutional improvements if unsupported by a wider strategy that seeks to enhance capacities and protocols. These findings are valuable, however, in making problems transparent and in creating the space for discussion.     

Permanent aggregations of a pelagic predator at shallow seamounts

The effectiveness of marine reserves for highly mobile reef fishes such as jacks and trevallies is normally assumed to be small, even though we generally lack the understanding of their long-term movement patterns. In this work, we combined the analysis of multi-year landings and underwater visual census with acoustic telemetry to investigate the long-term movement patterns (up to 4 years) of almaco jack, Seriola rivoliana, a large reef top predator, in one protected and one unprotected offshore shallow seamount in the Azores, central North Atlantic. Although the analysis of visual census and landing data suggests a pronounced seasonal pattern of occurrence, we found that tagged fish were almost continuously detected at the seamounts for up to four consecutive years. Some individuals showed a few long periods of undetection of 1–2 months in the Formigas reserve, mostly in the fall and winter. Mobility within this seamount increased during spring and summer, and geostrophic current speed was negatively correlated with detection probability. Overall, the acoustic telemetry results showed that adult almaco jacks were resident year-round, refuting the traditional view that these fish are essentially migratory and a seasonal occurrence in the Azores. Given the intrinsic vulnerability of resident fish to fishing, our results highlight the importance of protecting these sites in order to preserve these mature fish aggregations with high reproductive potential.