Extreme Values in TSP Distribution Functions

The highest values in annual TSP distributions fall below the best-fit, log-normal straight line more than one would expect from ordinary sampling statistics but not dramatically so. The lowest values in annual TSP distributions overwhelmingly fall below the best-fit, log-normal straight line. The most highly improbable high values above the best-fit line in such distributions are very questionable and probably do not represent true air quality values. The most improbable cases of highest values falling below the best-fit, log-normal line are the result of data artifacts at the opposite end of the data distribution. They do not represent low probabilities and probably do represent true air quality values. The most improbable low values are all of highly doubtful validity.     

Personal Exposure to Fine Particulate Matter in Elderly Subjects: Relation between Personal,Indoor, and Outdoor Concentrations

ABSTRACT

The time-series correlation between ambient levels, indoor levels, and personal exposure to PM_2.5 was assessed in panels of elderly subjects with cardiovascular disease in Amsterdam, the Netherlands, and Helsinki, Finland. Subjects were followed for 6 months with biweekly clinical visits. Each subject's indoor and personal exposure to PM_2.5 was measured biweekly, during the 24-hr period preceding the clinical visits. Outdoor PM_2.5 concentrations were measured at fixed sites. The absorption coefficients of all PM_2.5 filters were measured as a marker for elemental carbon (EC). Regression analyses were conducted for each subject separately, and the distribution of the individual regression and correlation coefficients was investigated. Personal, indoor, and ambient concentrations were highly correlated within subjects over time. Median Pearson's R between personal and outdoor PM_2.5 was 0.79 in Amsterdam and 0.76 in Helsinki. For absorption, these values were 0.93 and 0.81 for Amsterdam and Helsinki, respectively. The findings of this study provide further support for using fixed-site measurements as a measure of exposure to PM_2.5 in epidemiological time-series studies.     

Wintertime Vertical Variations in Particulate Matter (PM) and Precursor Concentrations in the San Joaquin Valley during the California Regional Coarse PM/Fine PM Air Quality Study

Abstract

Air quality monitoring was conducted at a rural site with a tower in the middle of California’s San Joaquin Valley (SJV) and at elevated sites in the foothills and mountains surrounding the SJV for the California Regional PM₁₀/M_2.5 Air Quality Study. Measurements at the surface and on a tower at 90 m were collected in Angiola, CA, from ecember 2000 through February 2001 and included hourly black carbon (BC), particle counts from optical particle counters, nitric oxide, ozone, temperature, relative humidity, wind speed, and direction. Boundary site measurements were made primarily using 24-hr integrated particulate matter (PM) samples. These measurements were used to understand the vertical variations of PM and PM precursors, the effect of stratification in the winter on concentrations and chemistry aloft and at the surface, and the impact of aloft-versus-surface transport on PM concentrations. Vertical variations of concentrations differed among individual species. The stratification may be important to atmospheric chemistry processes, particularly nighttime nitrate formation aloft, because NO₂ appeared to be oxidized by ozone in the stratified aloft layer. Additionally, increases in accumulation-mode particle concentrations in the aloft layer during a fine PM (PM_2.5) episode corresponded with increases in aloft nitrate, demonstrating the likelihood of an aloft nighttime nitrate formation mechanism. Evidence of local transport at the surface and regional transport aloft was found; transport processes also varied among the species. The distribution of BC appeared to be regional, and BC was often uniformly mixed vertically. Overall, the combination of time-resolved tower and surface measurements provided important insight into PM stratification, formation, and transport.     

Perfluorinated alkylated substances in vegetables collected in four European countries; occurrence and human exposure estimations

The human diet is recognised as one possible major exposure route to the overall perfluorinated alkylated substances (PFAS) burden of the human population, resulting directly from contamination of dietary food items, as well as migration of PFAS from food packaging or cookware. Most European countries carry out national monitoring programs (food basket studies) to monitor contamination with pollutants. Usually, for PFASs, non-coordinated approaches are used in Europe, since food basket studies are mainly carried out by national authorities following national requirements and questions, making comparisons between different countries difficult. A harmonised sampling campaign collecting similar food items in a uniform procedure enabling direct comparison between different regions in Europe was designed. We selected four countries (Belgium, Czech Republic, Italy and Norway), representing the four regions of Europe: West, East, South and North. In spring 2010 and 2011, 20 different types of vegetables were sampled in Belgium, Czech Republic, Italy and Norway. Perfluorinated carboxylic acids (PFCAs) were the main group of detected PFASs, with perfluorinated octanoic acid (PFOA) as the most abundant PFCA (with exception of samples from Czech Republic), followed by perfluorinated hexanoic acid and perfluorinated nonanoic acid. Dietary intake estimates for PFOA show only low human exposure due to vegetable consumption for adults and children, mostly governed by high intake of potatoes.     

Using iron-loaded sepiolite obtained by adsorption as a catalyst in the electro-Fenton oxidation of Reactive Black 5

This study explores the possibility of using iron-loaded sepiolite, obtained by recovering iron from polluted water, as a catalyst in the electro-Fenton oxidation of organic pollutants in textile effluents. The removal of iron ions from aqueous solution by adsorption on sepiolite was studied in batch tests at iron concentrations between 100 and 1,000 ppm. Electro-Fenton experiments were carried out in an electrochemical cell with a working volume of 0.15 L, an air flow of 1 L/min, and 3 g of iron-loaded sepiolite. An electric field was applied using a boron-doped diamond anode and a graphite sheet cathode connected to a direct current power supply with a constant potential drop. Reactive Black 5 (100 mg/L) was selected as the model dye. The adsorption isotherms proved the ability of the used adsorbent. The removal of the iron ion by adsorption on sepiolite was in the range of 80–100 % for the studied concentration range. The Langmuir and Freundlich isotherms were found to be applicable in terms of the relatively high regression values. Iron-loaded sepiolite could be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process. Successive batch processes were performed at optimal working conditions (5 V and pH 2). The results indicate the suitability of the proposed combined process, adsorption to iron remediation followed by the application of the obtained iron-loaded sepiolite to the electro-Fenton technique, to oxidize polluted effluents.     

Levels of organochlorine pesticides in Amazon turtle (Podocnemis unifilis) in the Xingu River,Brazil

Abstract

Due to the toxicity and high environmental persistence of organochlorine pesticides in aquatic organisms, turtles have been studied as environment biomonitors. These animals are important sources of protein for the riverside and indigenous peoples of the Brazilian amazon. In the present study, organochlorine pesticide contamination was investigated in Podocnemis unifilis. Liver, muscle and fatty tissue samples were removed from 50 specimens collected from five sampling points located in the Xingu River basin. Fourteen organochlorine pesticides were analysed via gas chromatography with an electron capture detector (CG-ECD). Eight organochlorine pesticides were detected with average concentrations of ∑DDT, ∑Endossulfan and ∑HCH which were 26.17?±?26.35, 14.38?±?23.77 and 1.39?±?8.46?ng g^?1 in moisture content, respectively. DDT compounds were the most predominant, with a greater concentration of pp′-DDT in the liver and pp′-DDD in the muscle. Significant differences were noted between the types of tissues studied, and the concentration of OCPs varied between sampling sites.     

Kinetic Behavior in Melt State and Solid State Polymerization of Lactide Using Magnesium Stearate as Catalyst

Solid state polymerizations (SSP) and the kinetic behavior in melt state of l-lactide polymerizations employing magnesium stearate as catalyst were investigated. The solid state polymerizations were carried out in two steps where pre-polymers were first prepared in melt polymerizations at 180 °C and the subsequent post-polymerizations were performed around the Tc of polylactide (PLA). In order to find the initial SSP conditions, kinetic profiles of melt polymerizations of l-lactide with magnesium stearate were determined. According to the kinetics data the melt polymerizations were found to be first order with respect to lactide as evident from a linear relationship of logarithmic variations of l-lactide concentration versus time using catalyst/monomer ratios of 1:500 and 1:5,000. When the catalyst content is increased to 1:100 the relationship loses its linearity due to fast propagation in the early stages of the reaction. From the GPC data it can be noted that the molecular weight of PLA can be increased by 5–17 times under the conditions established for our SSP experiments. A comparison between the two step solid state polymerizations and already reported melt polymerizations using the same catalyst showed that SSP furnished polymers with much lower amount of polymer degradation.     

Vehicle routing for the eco-efficient collection of household plastic waste

Plastic waste is a special category of municipal solid waste. Plastic waste collection is featured with various alternatives of collection methods (curbside/drop-off) and separation methods (source-/post-separation). In the Netherlands, the collection routes of plastic waste are the same as those of other waste, although plastic is different than other waste in terms of volume to weight ratio. This paper aims for redesigning the collection routes and compares the collection options of plastic waste using eco-efficiency as performance indicator. Eco-efficiency concerns the trade-off between environmental impacts, social issues and costs. The collection problem is modeled as a vehicle routing problem. A tabu search heuristic is used to improve the routes. Collection alternatives are compared by a scenario study approach. Real distances between locations are calculated with MapPoint. The scenario study is conducted based on real case data of the Dutch municipality Wageningen. Scenarios are designed according to the collection alternatives with different assumptions in collection method, vehicle type, collection frequency and collection points, etc. Results show that the current collection routes can be improved in terms of eco-efficiency performance by using our method. The source-separation drop-off collection scenario has the best performance for plastic collection assuming householders take the waste to the drop-off points in a sustainable manner. The model also shows to be an efficient decision support tool to investigate the impacts of future changes such as alternative vehicle type and different response rates.     

The Historical Dynamics of Social–Ecological Traps

Environmental degradation is a typical unintended outcome of collective human behavior. Hardin’s metaphor of the “tragedy of the commons” has become a conceived wisdom that captures the social dynamics leading to environmental degradation. Recently, “traps” has gained currency as an alternative concept to explain the rigidity of social and ecological processes that produce environmental degradation and livelihood impoverishment. The trap metaphor is, however, a great deal more complex compared to Hardin’s insight. This paper takes stock of studies using the trap metaphor. It argues that the concept includes time and history in the analysis, but only as background conditions and not as a factor of causality. From a historical–sociological perspective this is remarkable since social–ecological traps are clearly path-dependent processes, which are causally produced through a conjunction of events. To prove this point the paper conceptualizes social–ecological traps as a process instead of a condition, and systematically compares history and timing in one classic and three recent studies of social–ecological traps. Based on this comparison it concludes that conjunction of social and environmental events contributes profoundly to the production of trap processes. The paper further discusses the implications of this conclusion for policy intervention and outlines how future research might generalize insights from historical–sociological studies of traps.     

Controls on coarse wood decay in temperate tree species: birth of the LOGLIFE experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.