Polycyclic Aromatic Hydrocarbons in House Dust Samples : Source Identification and Apportionment

House dust is a heterogeneous matrix, consisting of a variety of inorganic, organic and biological materials. Once pollutants are adsorbed onto house dust particles, they either do not degrade at all or degrade at rates that are relatively slower than their ambient counterparts. Thus house dusts are useful reservoirs for chronic exposure to indoor pollutants. In this study, house dust samples from suburban houses in Brisbane, Australia were collected in summer 2004 and winter 2005. Given the growing need to understand the potential risks of indoor pollutants and to develop appropriate control strategies, the objective of the study was to use receptor-oriented models to estimate the number of sources, their compositions and the contribution of each source to the samples. Thus the polycyclic aromatic hydrocarbon (PAH) composition data were analyzed with advanced factor analysis models. Four factors were required to reproduce the summer data well and each factor had distinctive compositions that suggested that natural gas utilities, cooking, vehicle emissions and miscellaneous combustion processes are the main sources of PAHs in the samples. The implications of the results and of the observed correlation between the building characteristics and the PAH profiles on the quality of these indoor microenvironments and the development of control strategies are discussed

Role of solids in heavy metals build-up on urban road surfaces

Solids are widely identified as a carrier of harmful pollutants in stormwater runoff exerting a significant risk to receiving waters. This paper outlines the findings of an in-depth investigation on heavy metal adsorption to solids surfaces. Pollutant build-up samples collected from sixteen road sites in residential, industrial and commercial land uses were separated into four particle size ranges and analysed for a range of physico-chemical parameters and nine heavy metals including Iron (Fe), Aluminum (Al), Lead (Pb), Zinc (Zn), Cadmium (Cd), Chromium (Cr), Manganese (Mn), Nickel (Ni) and Copper (Cu). High specific surface area (SSA) and total organic carbon (TOC) content in finer particle size ranges was noted, thus confirming strong correlations with heavy metals. Based on their physico-chemical characteristics, two different types of solids originating from traffic and soil sources were identified. Solids generated by traffic were associated with high loads of heavy metals such as Cd and Cr with strong correlation with SSA. This suggested the existence of surface dependent bonds such as cation exchange between heavy metals and solids. In contrast, Fe, Al and Mn which can be attributed to soil inputs showed strong correlation with TOC suggesting strong bonds such as chemsorption. Zn was found to be primarily attached to solids by bonding with the oxides of Fe, Al and Mn. The data analysis also confirmed the predominance of the finer fraction, with 70% of the solids being finer than 150 µm and containing 60% of the heavy metal pollutant load

Der Elysée-Vertrag: Ein deutsch-französischer Erinnerungsort im Landeskundeunterricht für Deutsch als Fremdsprache

Schrader A. Der Elysée-Vertrag: Ein deutsch-französischer Erinnerungsort im Landeskundeunterricht für Deutsch als Fremdsprache. Bielefeld: Universität Bielefeld; 2019

Surface Characterisation of Selected Sorbent Materials For Common Hydrocarbon Fuels

The need to find the most efficient material for the clean-up of oil/fuel spills both at sea and on land is of extreme importance. Generally, this requires material selection based upon the adsorption properties of selected sorbent materials such as sand, swelling clays, organo-clays and cotton fibres. These adsorption properties are a function of the surface characterisation where hydrophobic and oleophilic properties are essential. From BET analysis, the adsorption isotherm of the selected materials was type II and IV in the IUPAC classification scheme. The main adsorption mechanism for these sorbents occurred on the external surface of the material in the pores or capillaries. ESEM studies indicate that cotton capillaries contribute significantly to the adsorption process of oil. In addition, the presence of surface wax on cotton-cellulose fibre facilitated the uptake by: a) providing a relatively hydrophobic surface for sorption of organics; and b) providing a low surface energy environment for the capillaries to aid in oil transport. Cotton fibre was observed to have several key properties such as hydrophobicity, good affinity for hydrocarbons, rapid adsorption on contact, and high adsorption and retention through interfibre capillaries. This research provides the basis for selection of cotton–cellulose fibres compared to common and other novel alternatives such as sand and organo-clays, respectively

Adsorption of Hydrocarbons on Organo-Clays - Implications For Oil Spill Remediation

Organoclays synthesised by the ion exchange of sodium in Wyoming Na-Montmorillonite (SWy-2-MMT) with three surfactants octadecyltrimethylammonium bromide (ODTMA) formula C21H46NBr b) didecyldimethylammonium bromide (DDDMA), formula C22H48BrN, and c) di(hydrogenated tallow)dimethylammonium chloride (tallow) were tested for hydrocarbon adsorption. Using diesel, hydraulic oil and engine oil an evaluation was made of the effectiveness of the sorbent materials for a range of hydrocarbon products that are likely to be involved in land-based oil spills. It was found that the hydrocarbon sorption capacity of the organo-clays depended upon the materials and surfactants used in the organoclay synthesis. Greater adsorption was obtained if the surfactant contained two or more hydrocarbon long chains. Extensive utilisation of chemometrics principally with the aid of MCDM methods, produced models which consistently ranked the organoclays well above any of the competitors including commercial benchmark materials. Thus the use of organo-clays for cleaning up oil spills is feasible due to its many desirable properties such as high hydrocarbon sorption and retention capacities, hydrophobicity. The negative effects of the use of organoclays for oil-spill cleanup are the cost, the biodegradability, and recyclability of the organo-clay

Understanding nutrient build-up on urban road surfaces

This paper discusses the outcomes of a research project on nutrients build-up on urban road surfaces. Nutrient build-up was investigated on road sites belonging to residential, industrial and commercial land use. Collected build-up samples were separated into five particle size ranges and were tested for total nitrogen (TN), total phosphorus (TP) and sub species of nutrients, namely, NO2-, NO3-, TKN and PO43-. Multivariate analytical techniques were used to analyse the data and to develop detailed understanding on build-up. Data analysis revealed that the solids loads on urban road surfaces are highly influenced by factors such as land use, antecedent dry period and traffic volume. However, the nutrient build-up process was found to be independent of the type of land use. It was solely dependent on the particle size of solids build-up. Most of the nutrients were associated with the particle size range <150 μm. Therefore, the removal of particles below 150 µm from road surfaces is of importance for the removal of nitrogen and phosphorus from road surface solids build-up. It is also important to consider the differences in the composition of nitrogen and phosphorus build-up in the context of designing effective stormwater quality mitigation strategies

Exploratory Multivariate Modeling and Prediction of The Physico-Chemical Properties of Surface Water and Groundwater

Physico-chemical properties of surface water and groundwater samples from some developing countries have been subjected to multivariate analyses by the non-parametric multi-criteria decision-making methods, PROMETHEE and GAIA. Complete ranking information necessary to select one source of water in preference to all others was obtained, and this enabled relationships between the physico-chemical properties and water quality to be assessed. Thus, the ranking of the quality of the water bodies was found to be strongly dependent on the total dissolved solid, phosphate, sulfate, ammonia-nitrogen, calcium, iron, chloride, magnesium, zinc, nitrate and fluoride contents of the waters. However, potassium, manganese and zinc composition showed the least influence in differentiating the water bodies. To model and predict the water quality influencing parameters, partial least square analyses were carried out on a matrix made up of the results of water quality assessment studies carried out in Nigeria, Papua New Guinea, Egypt, Thailand and India/Pakistan. The results showed that the total dissolved solid, calcium, sulfate, sodium and chloride contents can be used to predict a wide range of physico-chemical characteristics of water. The potential implications of these observations on the financial and opportunity costs associated with elaborate water quality monitoring are discussed

Application of Multicriteria Decision Making Methods to Air Quality in the Microenvironments of Residential Houses in Brisbane, Australia

This paper reports the first application of the multicriteria decision making methods, PROMETHEE and GAIA, to indoor and outdoor air quality data. Fourteen residential houses in a suburb of Brisbane, Australia were investigated for 21 air quality-influencing criteria, which included the characteristics of the houses as well as the concentrations of volatile organic compounds, fungi, bacteria, submicrometer, and supermicrometer particles in their indoor and outdoor air samples. Ranking information necessary to select one house in preference to all others and to assess the parameters influencing the differentiation of the houses was found with the aid of PROMETHEE and GAIA. There was no correlation between the rank order of each house and the health complaints of its occupants. Patterns in GAIA plots show that indoor air quality in these houses is strongly dependent on the characteristics of the houses (construction material, distance of the house from a major road, and the presence of an in-built garage). Marked similarities were observed in the patterns obtained when GAIA and factor analysis were applied to the data. This underscores the potential of PROMETHEE and GAIA to provide information that can assist source apportionment and elucidation of effective remedial measures for indoor air pollution

Impacts of traffic and rainfall characteristics on heavy metals build-up and wash-off from urban roads

An investigation into the effects of changes in urban traffic characteristics due to rapid urbanisation and the predicted changes in rainfall characteristics due to climate change on the build-up and wash-off of heavy metals was carried out in Gold Coast, Australia. The study sites encompassed three different urban land uses. Nine heavy metals commonly associated with traffic emissions were selected. The results were interpreted using multivariate data analysis and decision making tools, such as principal component analysis (PCA), fuzzy clustering (FC), PROMETHEE and GAIA. Initial analyses established high, low and moderate traffic scenarios as well as low, low to moderate, moderate, high and extreme rainfall scenarios for build-up and wash-off investigations. GAIA analyses established that moderate to high traffic scenarios could affect the build-up while moderate to high rainfall scenarios could affect the wash-off of heavy metals under changed conditions. However, in wash-off, metal concentrations in 1-75µm fraction were found to be independent of the changes to rainfall characteristics. In build-up, high traffic activities in commercial and industrial areas influenced the accumulation of heavy metal concentrations in particulate size range from 75 - >300 µm, whereas metal concentrations in finer size range of 300 µm can be targeted for removal of Ni, Cu, Pb, Cd, Cr and Zn from build-up whilst organic matter from 300 µm can be targeted for removal of Cd, Cr, Pb and Ni from wash-off. Cu and Zn need to be removed as free ions from most fractions in wash-off

Porous Materials for Oil Spill Cleanup: A Review of Synthesis and Absorbing Properties

This paper reviews the synthesis and the absorbing properties of the wide variety of porous sorbent materials that have been studied for application in the removal of organics, particularly in the area of oil spill cleanup. The discussion is especially focused on hydrophobic silica aerogels, zeolites, organoclays and natural sorbents many of which have been demonstrated to exhibit (or show potential to exhibit) excellent oil absorption properties. The areas for further development of some of these materials are identified.</i