Removal of imidazolium- and pyridinium-based ionic liquids by Fenton oxidation

The oxidation of imidazolium (1-hexyl-3-methylimidazolium chloride, HmimCl) and pyridinium (1-butyl-4-methylpyridinium chloride, BmpyrCl) ionic liquids (ILs) by Fenton’s reagent has been studied. Complete conversion was achieved for both ILs using the stoichiometric H₂O₂ dose at 70 °C, reaching final TOC conversion values around 45 and 55% for HmimCl and BmpyrCl, respectively. The decrease in hydrogen peroxide dose to substoichiometric concentrations (20–80% stoichiometric dose) caused a decrease in TOC conversion and COD removal and the appearance of hydroxylated oxidation by-products. Working at these substoichiometric H₂O₂ doses allowed the depiction of a possible degradation pathway for the oxidation of both imidazolium and pyridinium ILs. The first step of the oxidation process consisted in the hydroxylation of the ionic liquid by the attack of the ·OH radicals, followed by the ring-opening and the formation of short-chain organic acids, which could be partially oxidized up to CO₂ and H₂O. At H₂O₂ doses near stoichiometric values (80%), the resulting effluents showed non-ecotoxic behaviour and more biodegradable character (BOD₅/COD ratio around 0.38 and 0.58 for HmimCl and BmpyrCl, respectively) due to the formation of short-chain organic acids.

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Characterization of urban solid waste in Chihuahua, Mexico

The characterization of urban solid waste generation is fundamental for adequate decision making in the management strategy of urban solid waste in a city. The objective of this study is to characterize the waste generated in the households of Chihuahua city, and to compare the results obtained in areas of the city with three different socioeconomic levels. In order to identify the different socioeconomic trends in waste generation and characterization, 560 samples of solid waste were collected during 1 week from 80 households in Chihuahua and were hand sorted and classified into 15 weighted fractions. The average waste generation in Chihuahua calculated in this study was 0.676 kg per capita per day in April 2006. The main fractions were: organic (48%), paper (16%) and plastic (12%). Results show an increased waste generation associated with the socioeconomic level. The characterization in amount and composition of urban waste is the first step needed for the successful implementation of an integral waste management system.     

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.     

Ground-Level Ozone in Eastern Canada: Seasonal Variations,Trends, and Occurrences of High Concentrations

Over the past few years, concern has increased in Canada over the health and environmental impacts of elevated concentrations of ground-level ozone. During the summer the most populated regions of Canada frequently record ozone concentrations that exceed the one-hour average maximum acceptable air quality objective of 32 parts per billion (ppb). In 1988 the Canadian Council of Ministers of the Environment agreed to develop a federal/provincial management plan to control nitrogen oxide and volatile organic compound emissions to reduce ozone concentrations in all affected regions of the country. In addition to the proposed interim control measures, the plan recommended that studies be undertaken to acquire the information necessary to develop sound control strategies. This report represents one of those studies and provides a summary of ground-level ozone measurements for eastern Canada for the 1980 to 1991 period with an emphasis on seasonal variations, trends, and occurrences of high concentrations.

Southwestern Ontario experiences the highest maximum hourly ozone concentrations and the greatest frequency of hours greater than the 82 ppb acceptable objective. Urban sites have the highest frequencies of ozone concentration measurements in the < 10 ppb range, while rural and remote sites show peaks in frequency distribution in the 20 to 30 ppb range. Trend analysis of summertime (May to September) average daily maximum ozone concentration showed no consistent pattern for eastern Canadian sites during 1980 to 1991. Sites in Montreal showed statistically insignificant downward trends while sites in Toronto showed small but statistically significant upward trends. These ozone-increasing trends are associated with reductions in nitric oxide concentrations. At all sites there was large year-to-year variability in peak ozone levels and in the frequency of hours with ozone concentrations above the maximum acceptable objective.     

Prenatal diagnosis of fragile x syndrome: (cgg)n expansion and methylation of chorionic villus samples

Fragile X syndrome is the most common form of inherited mental retardation, due to an expansion of the (CGG)_n trinucleotide repeat in the FMR-1 gene and hypermethylation of its 5′ upstream CpG island. Two major problems remain to be resolved for fragile X prenatal diagnosis: the abnormal methylation patterns of chorionic villus samples (CVS) and the inability to predict the mental status of females with the full mutation. We present here the results of ten prenatal diagnoses of fragile X syndrome using Southern blotting and polymerase chain reaction (PCR) amplification, and the analysis of 50 further CVS to test the methylation status of the CpG island of the FMR-1 gene. In the ten ‘at-risk’ CVS, eight normal (five males and three females) and two affected male fetuses were detected. Absence of methylation in the CVS was observed in two cases, which was not found upon subsequent examination of the newborn or of fetal tissues. In the 50 CVS not ‘at risk’ for fragile X syndrome, abnormal fragment patterns for probe StB12.3 were detected in 32 per cent for female and 24 per cent for male fetuses. This abnormal pattern could be due to absent or partial methylation of the CpG island of the FMR-1 gene in chorionic villus tissues.     

Improvement of coagulation-flocculation process using anionic polyacrylamide as coagulant aid

A physicochemical treatment (coagulation-flocculation) was applied to a slaughterhouse wastewater, using anionic polyacrylamide as coagulant aid to improve the settling velocity of the flocs formed with the coagulants used: ferric sulphate, aluminium sulphate and polyaluminium chloride. The optimum speed and stirring time for the flocculation stage were ascertained along with the optimum pH and coagulant and coagulant aid doses. The speed and coagulation time were initially set according to recommendations in the literature concerning the treatment of this type of water. Chemical oxygen demand (COD), biochemical oxygen demand at 5 days (BOD5) and total suspended solids (TSS) were recorded at the beginning and end of each experiment in order to monitor the process. Once the optimal conditions had been established, several parameters were measured in order to assess the coagulation-flocculation process: particle number and size, sludge volume, nutrients (ammonia nitrogen, total Kjeldahl nitrogen, albuminoid nitrogen, orthophosphate, total phosphorus) and the residual concentration of iron and aluminium in clarified water. Anionic polyacrylamide, when added with ferric sulphate or polyaluminium chloride led to a significant increase in the settling speed.     

Growth,mortality and disease susceptibility of oyster<Emphasis Type="Italic"> Ostrea edulis</Emphasis> families obtained from brood stocks of different geographical origins,through on-growing in the Ría de Arousa (Galicia,NW Spain)

Infection by Bonamia ostreae has caused extensive mortalities of oysters Ostrea edulis through European and United States coasts for at least 25 years. The development of a bonamiosis-resistant strain seems a promising strategy to fight against the disease. As a first step, evaluation of variability in productive traits and disease susceptibility of European populations was performed to identify favourable oyster populations with which to start selective breeding in Galicia (NW Spain). Oysters taken from Greece, Ireland, Ortigueira (Galicia) and Coroso (Galicia) were used as brood stock, and 19 seed families were produced (4–5 families from each origin). The oyster families were used to assess variability through on-growing in an area of the Ría de Arousa heavily affected by bonamiosis. Results showed significant differences in growth, mortality and susceptibility to bonamiosis and other diseases, both between origins and between families under origins. Bonamiosis was associated with mortality in the late stage of oyster on-growing. Indications of natural selection of bonamiosis less-susceptible oysters due to the long exposure of the Ortigueira population to bonamiosis were found. Other symbionts and pathological conditions were detected, of which herpes-like viral infections and disseminated neoplasia could also cause mortality. An index of the overall incidence of pathological conditions (OIPC) was estimated for each family. A significant correlation between the OIPC and the cumulative mortality of the families was noted. On average, oysters from autochthonous origins showed better performance. The results obtained with the best-performing families suggest that the profitability of oyster farming in Galicia would improve, even under bonamiosis pressure, by using appropriate oyster spat.Communicated by S.A. Poulet, Roscoff     

Comparison of residue levels of persistent organochlorine compounds in butter from Spain and from other European countries

Abstract

Commercially available butter from Spain (n=36) and from other European countries (n=20) has been analyzed by high resolution gas chromatography with an electron capture detector for organochlorine contaminants. The results showed that both groups of samples have a similar pattern of these pollutants, but in all cases where significant differences in concentrations were found, Spanish samples presented higher values. This was especially notable for lindane (median values 11.6 vs. 3.0 ng/g wet weight), hexachlorobenzene (6.4 vs. 0.5) and ß‐hexachlorocyclohexane (3.1 vs. 1.2). Total PCBs showed no differences (5.4 vs. 6.6), but detailed analysis of congener composition indicated a higher presence in Spanish samples of the most persistent chlorinated PCBs. No sample presented levels of concern for any single organochlorine compound. It is interesting to note that consumption of butter in Spain is low so, although levels of organochlorines are higher than those found in other countries, consumers are less exposed through this foodstuff than in other European countries. These results also confirm the fact that environmental pollution by organochlorines is more important in Spain than in the rest of Europe.     

An index to quantify street cleanliness: The case of Granada (Spain)

Urban surfaces receive waste deposits from natural and human sources, which create a negative visual impact and are identified as potentially significant contributors to water and air pollution. Local councils are usually responsible for the sweep of roads and footpaths to keep the environment clean and free of litter. Quality controls are useful in order to check whether the services are being executed according to the quantity, quality and performance standards that are provided. In this sense, several factors might affect the efficiency of the management of cleaning and waste collection services; however, only a few contributions are available in the literature on the various aspects associated with the level of street cleanliness. In this paper, the suitability of a Cleanliness Index has been checked, for the case of Granada (South of Spain), in order to contribute to the proper management of public expenditure, improving the quality and cost of an essential service for any municipality. Results have concluded that the city exhibits a good level of cleanliness, although the standard of cleaning varied from one area of the city to another. The Cleaning Index fits well to the general situation of the different districts of Granada and thus, it could be considered a useful tool for measuring the level of cleanliness of the streets of the city and for evaluating the organization of the cleaning service, such that an outsourced company would not be responsible for controlling all the cleaning services.