Analysis of two schemes using micro hydroelectric power (MHPs) in the Amazon with environmental sustainability and energy and economic feasibility

A major problem for sustainable development in the Amazon is the difficulty of supplying electric power to isolated communities, which represent a considerable share of the population. This problem has been a major obstacle to productive activities (especially extractive and agricultural) in such communities, thus significantly contributing to rural drift and creating social problems in larger cities. In that case, one way to supply electric power would be to use the huge network of small rivers in the region by implementing Micro Hydroelectric Power Plants (MHPs). However, this type of hydropower project requires a set of technical assessments in order to obtain better value for its cost-effectiveness from the perspective of sustainable development. Thus, based on a survey of energy demand and the local hydrological and topographical characteristics, two possible MHP designs for the hydrological site under analysis were suggested. Assessments of hydropower, economic and environmental aspects were developed. MHP designs were compared with the diesel generator design of the community under focus. Comparison showed that the MHP designs are feasible in terms of energy to meet local demand; economically, they are more feasible than the diesel generator and are environmentally sustainable, mainly because such designs involve low-head, run-of-river MHPs and the flooded areas were simulated and are not larger than 0.02 km². Therefore, the information provided by these assessments constitutes important data, serving as subsidies for MHP implementation projects, which shall contribute to sustainable development in the region.     

Toxicity of tire debris leachates

Data on the indicators of environmental impact of tire debris, originated from the tire abrasion on roads, are extremely scarce, while it is well known that tires may produce deleterious effects. Tire debris contains significant quantities of zinc (Zn) which may be released by tire rubber. We have used tire particles (TD) produced in laboratory from new rubber. Two sets of experiments were set up to obtain eluates. One set used 50 and 100 g/L TD to produce eluates at pH 3-7. The Zn quantity was measured with a Inductively Coupled Plasma-Atomic Emission Spectrometry. The eluates at 1%,10%,50%,100% concentrations in culture media were tested on Raphidocelis subcapitata, Daphnia magna and Xenopus laevis embryos (FETAX test). The other set of experiments was performed putting 250 mg/L TD in a column with glass beads to control particle dispersion during the elution process. We demonstrate that factors such as pH, size and particles aggregation deeply influence the elution process, that the amount of Zn leached from particles is related to their aggregation rather than their quantity. These results, even though do not reflect the real environmental toxicity of the leachates, can be successfully used for comparative purposes allowing an initial assessment of the potential effect of tire derived particles.     

Water quality index for agricultural systems in Northwest Uruguay

Agricultural systems have experienced rapid expansion and intensification in the last several decades. In Uruguay, since the beginning of 2000, the most common cropping systems have included soybeans. Currently, this crop is expanding towards lowlands traditionally occupied by rice in rotation with pastures. However, the environmental effects of agricultural intensification and diversification are not well known. Thus, some indices have been proposed to quantify the changes in agricultural production systems and assess water quality. The main goal of this study was to develop a water quality index (WQI) to assess the impacts of the diversification of rice production systems in northwest Uruguay. The study was carried out in an agricultural basin where other summer crops have been incorporated in the rice-pasture sequence. Agriculture intensification and crop diversification indices were calculated using information provided by farmers. Water samples were collected downstream of the production area before crop sowing and after crop harvest (2008–2009 to 2010–2011 and 2016–2017 to 2017–2018). Biochemical oxygen demand, nitrates, total phosphorus, fecal coliforms, and total suspended solids were the variables that mainly explained the effects of the agricultural activities on water quality. The proposed water quality index included these unweighted variables, which allowed for the pre-sowing and post-harvest to be differentiated, as well as the degree of diversification. Therefore, the proposed WQI constitutes a tool that can be used to evaluate the water quality in an agricultural basin. Likewise, it can be used to select agricultural sequences that generate the least possible impacts on the associated water resources.     

Lactational exposure to phthalates in Southern Italy

BackgroundPhthalates, reproductive toxicants in animals, are synthetic chemicals with ubiquitous human exposures because of their extensive use, with potential detrimental health effects. Infants are considered to represent a population at increased risk, as they are exposed early in life to several different sources of exposure to phthalates.Objectives and methodsLittle information exists on phthalate exposure through breast milk from different geographic areas. By means of a LC/LC–MS/MS method we tested the presence of several different phthalate metabolites in breast milk from 62 healthy mothers living in Southern Italy.ResultsThe simple monoesters mono-isobutyl phthalate (MiBP) (median 18.8 μg/l) and mono(2-ethylhexyl) phthalate (MEHP) (median 8.4 μg/l) were present in all milk samples, whereas mono-n-butyl phthalate (MnBP) (median 1.5 μg/l) and mono-benzyl phthalate (MBzP) (median < 0.3 μg/l) were found in 64.5% and 43.5% of the samples, respectively. Among the oxidative metabolites of DEHP and DiNP only mono(2-ethyl-5-carboxypentyl) phthalate (5cx-MEPP) and monoisononyl phthalate with one hydroxyl group (OH-MiNP) were detectable in one and 13 samples (21%), respectively.ConclusionsThese findings indicate that exposure to phthalates through breast milk in Southern Italian infants is comparable to that of other countries, thus confirming that human milk may represent an additional potential source of phthalate exposure in a population at increased risk. However, different milk concentrations of MiBP may suggest a different pattern of usage of di-iso-butyl phthalate in Europe, as compared to USA, whereas for the first time, we detected an oxidative DiNP metabolite, whose significance remains unclear.     

Minimizing external indirect health costs due to aerosol population exposure: a case study from Northern Italy

Environmental Agencies require Decision Support Systems, in order to plan Air Quality Policies considering the cost of emission reduction measures and the human health effects (with related social costs). The use of Decision Support Systems is also useful to spread information to general public, explaining the effectiveness of proposed air quality plans. In this paper, a multi-objective approach to control PM10 concentration at a regional level is presented. The problem considers both the internal costs (due to the implementation of emission reduction measures) and the external costs (due to population exposure to high PM10 concentrations). To model PM10 concentrations, a single surrogate model is used for the entire domain, allowing the implementation of a very efficient optimization procedure. The surrogate model is derived through a set of 10 simulations, performed using a Chemistry Transport Model fed with different emission reduction scenarios. The methodology is applied to Northern Italy, a region affected by very high PM10 concentrations that exceed the limit values specified by the EU legislation.     

The significance of futures trading in minerals and oil

Futures trading has been introduced for aluminium and oil in recent years and the range of contracts available on various minerals and oil products continues to widen. Concern has been expressed by producers of a number of minerals, including nickel and platinum, that the introduction of futures trading may introduce a speculative element to price determination that will create inappropriate or excessively volatile prices. It is the purpose of this article to analyse the role of futures trading in relation to trade in underlying commodities in general and especially for trade in minerals and oil. Evidence from oil and platinum markets, in particular, is adduced and examined in the light of earlier evidence of the influence of futures trading on underlying commodities. The contribution of futures trading is examined in detail and conclusions are reached on the significance of futures trading for minerals and oil.     

Combinations of Horizontal and Vertical Flow Constructed Wetlands to Improve Nitrogen Removal

Nitrogen removal in wetlands is achieved through two pathways: (a) N cycling and (b) storage. N cycling is a permanent removal pathway. There has been an increasing interest in the development of technologies to alleviate permanent nitrogen removal limitation in constructed wetlands by ensuring prevalence of conditions enhancing N cycling. The purpose of this study is to review an emerging technology of vegetated submerged bed constructed wetland system aimed at improving nitrogen removal in wetlands through rational system design. The design and performance of this system type is evaluated. The oxygen transfer capacity and nitrogen removal mechanisms on system performance are evaluated. Constructed wetland combinations most commonly consist of vertical flow (VF) and horizontal flow (HF) beds where VF and HF are aimed at nitrification and denitrification, respectively. Nitrate nitrogen accumulation is the most limiting factor in typical VF based systems.     

Optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater

Chemical, electrochemical and flow variables were optimized to examine the effectiveness of the electrocoagulation process for the removal of copper, lead and cadmium. The electrochemical process, which uses electrodes of commercial laminate steel, was applied to simulated wastewater containing 12 mg dm(-3) of copper, 4 mg dm(-3) of lead and 4 mg dm(-3) of cadmium. The optimum conditions for the process were identified as pH=7, flow rate=6.3 cm(3) min(-1) and a current density between 31 and 54 A m(-2). When the electrode geometric area and time of electrolysis reached critical values, the copper removal reached a maximum value of 80%. A linear relationship was identified between the current density and the mass of generated sludge. In addition, a linear relationship was found between specific energy consumption and current density. The results of this investigation provide important data for the development of an industrial-scale electrolytic reactor.