Metal size distribution in rainfall and snowmelt-induced runoff from three urban catchments

The size distribution of metals transported by urban runoff has implications for treatment type and design, predicting their mobility and evaluating their potential impact on receiving waters. There is an urgent need to better understand the distribution of metals between fractions, particularly those in the sub-dissolved fractions. As a contribution to addressing this need, this study characterises the size distribution of Cd, Cr, Cu, Ni, V and Zn using conventional and novel techniques. Data is presented as event mean concentrations (EMC) of a total of 18 rainfall and snowmelt events at three urban sites. For all studied metals in all events and at all sites, the contribution of the truly dissolved fraction made a greater contribution to the total concentrations than the colloidal fraction. Truly dissolved Cd and Zn concentrations contributed (on average) 26% and 28% respectively, of the total EMCs with truly dissolved Cu and Ni contributing (on average) 18%. In contrast, only 1% (V) and 3% (Cr) were identified in the truly dissolved fraction. The greatest contribution of truly dissolved Cd, Cu and Zn concentrations (relative to total oncentrations) were reported during rainfall events. However, no seasonal differences were identified and differences between the sites regarding the EMCs distribution by fractions were not at a statistically significant level (p N 0.05) for any metal or event. The loads of truly dissolved and colloidal metals did not follow the patterns of particulate metal loads indicating particulates are not the main source of subdissolved metals. The data suggests that ultrafiltration as a treatment technique would not efficiently mitigate the risks posed by metals to receiving water cologie

Socio-economic impacts of Corporate Social Responsibilitypractices in Sri Lankan domestic manufacturing companies : (with reference to Harischandra Mills PLC, Matara, Sri Lanka)

The purpose of this study is to explore the socio-economic impacts of Corporate Social Responsibility (CSR) practices in Sri Lankan manufacturing companies. The thesis sets out to seek how CSR activities can obtain business benefits as well how it appeals to the socioeconomic issues in the community. To achieve the aim of this study, an investigation of the current practices was performed through a pertinent empirical study. The empirical investigation is based on a case study of Harischandra Mills PLC CSR practices. It shows an increasing concern of the company to participate in social programmes to contribute socio-economic issues of the community. The author’s review of the literature highlights the importance of CSR activities. Although a widespread definition is not available, CSR has gained an immense attention during past years. Many business firms perform CSR initiatives to pursue their economic, social and environmental responsibilities while interacting with their stakeholders. Today, stakeholders look increasingly at companies to answer to many socio-economic problems in the community. The CSR practices ensure gains for all stakeholders involved while enhancing business benefits. Awareness and sense of necessity for practicing CSR is important factors to achieve fruitful benefits of CSR to address the long-term development needs in a sustainable way

Source characterisation of urban road surface pollutants for enhanced water quality predictions

This study developed a comprehensive research methodology for identification and quantification of sources responsible for pollutant build-up and wash-off from urban road surfaces. The study identified soil and asphalt wear, and non-combusted diesel fuel as the most influential sources for metal and hydrocarbon pollution respectively. The study also developed mathematical models to relate contributions from identified sources to underlying site specific factors such as land use and traffic. Developed mathematical model will play a key role in urban planning practices, enabling the implementation of effective water pollution control strategies

Impact of Total Debt on the Economic Growth of Sri Lanka

<p><strong>Abstract: </strong>Public debt is one of the key fiscal policy variables that can influence the economic growth of any country. For this reason, policymakers and economists have worried about the relationship between debt and growth. Empirical studies of the relationship between debt and growth have, however, been recently contested because of their mixed results; negative vs positive and linear vs non-linear. There are several main theoretical perspectives which underpin this relationship between debt and growth. Sri Lanka has accumulated a large amount of debt over the past six decades from both domestic sources and external sources. Accordingly, the main objective of this study is to assess the impact of public debt on economic growth in Sri Lanka using time series data from 1960 to 2016. Thus, this study involves two analysis stages. The first one is an aggregate analysis, which assesses the impact of total debt on economic growth. The second one is a disaggregate analysis, which assesses the impact of domestic debt and external debt on economic growth separately. This study implements the Structural Vector Auto Regression (SVAR) approach to examine the impact of public debt on GDP growth in a short- term as well as medium-term in Sri Lanka. This study confirms that total debt has a negative impact on GDP growth in Sri Lanka. In addition, based on the disaggregate analysis, we can conclude that domestic debt has a negative and significant linear relationship with GDP growth in Sri Lanka and external debt has a positive but insignificant relationship with GDP growth in Sri Lanka. Moreover, this study shows that debt service has a negative but insignificant impact on GDP growth in SriLanka.</p><p><strong>Keywords</strong>: Public debt, Domestic debt, External debt, Economic growth, Sri Lanka</p&gt

Variability of metal composition and concentrations\ud in road dust in the urban environment

Urban road dust comprises of a range of potentially toxic metal elements and plays a critical role in degrading urban receiving water quality. Hence, assessing the metal composition and concentration in urban road dust is a high priority. This study investigated the variability of metal composition and concentrations in road dust in 4 different urban land uses in Gold Coast, Australia. Samples from 16 road sites were collected and tested for selected 12 metal species. The data set was analyzed using both univariate and multivariate techniques. Outcomes of the data analysis revealed that the metal concentrations in road dust differ considerably within and between different land uses. Iron, aluminum, magnesium and zinc are the most abundant in urban land uses. It was also noted that metal species such as titanium, nickel, copper and zinc have the highest concentrations in industrial land use. The study outcomes revealed that soil and traffic related sources as key sources of metals deposited on road surfaces

Sources of hydrocarbons in urban road dust: Identification, quantification and prediction

Among urban stormwater pollutants, hydrocarbons are a significant environmental concern due to their toxicity and relatively stable chemical structure. This study focused on the identification of hydrocarbon contributing sources to urban road dust and approaches for the quantification of pollutant loads to enhance the design of source control measures. The study confirmed the validity of the use of mathematical techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA) for source identification and principal component analysis/absolute principal component scores (PCA/APCS) receptor model for pollutant load quantification. Study outcomes identified non-combusted lubrication oils, non-combusted diesel fuels and tyre and asphalt wear as the three most critical urban hydrocarbon sources. The site specific variabilities of contributions from sources were replicated using three mathematical models. The models employed predictor variables of daily traffic volume (DTV), road surface texture depth (TD), slope of the road section (SLP), effective population (EPOP) and effective impervious fraction (EIF), which can be considered as the five governing parameters of pollutant generation, deposition and redistribution. Models were developed such that they can be applicable in determining hydrocarbon contributions from urban sites enabling effective design of source control measures

Variability of metal composition and concentrations in road dust in the urban environment

Urban road dust comprises of a range of potentially toxic metal elements and plays a critical role in degrading urban receiving water quality. Hence, assessing the metal composition and concentration in urban road dust is a high priority. This study investigated the variability of metal composition and concentrations in road dust in 4 different urban land uses in Gold Coast, Australia. Samples from 16 road sites were collected and tested for selected 12 metal species. The data set was analyzed using both univariate and multivariate techniques. Outcomes of the data analysis revealed that the metal concentrations in road dust differ considerably within and between different land uses. Iron, aluminum, magnesium and zinc are the most abundant in urban land uses. It was also noted that metal species such as titanium, nickel, copper and zinc have the highest concentrations in industrial land use. The study outcomes revealed that soil and traffic related sources as key sources of metals deposited on road surfaces

Use of physicochemical signatures to assess the sources of metals in urban road dust

Road deposited dust is a complex mixture of pollutants derived from a wide range of sources. Accurate identification of these sources is seminal for effective source-oriented control measures. A range of techniques such as enrichment factor analysis (EF), principal component analysis (PCA) and hierarchical cluster analysis (HCA) are available for identifying sources of complex mixtures. However, they have multiple deficiencies when applied individually. This study presents an approach for the effective utilisation of EF, PCA and HCA for source identification, so that their specific deficiencies on an individual basis are eliminated. EF analysis confirmed the non-soil origin of metals such as Na, Cu, Cd, Zn, Sn, K, Ca, Sb, Ba, Ti, Ni and Mo providing guidance in the identification of anthropogenic sources. PCA and HCA identified four sources, with soil and asphalt wear in combination being the most prominent sources. Other sources were tyre wear, brake wear and sea salt

Hierarchy of factors which influence polycyclic aromatic hydrocarbons (PAHs) distribution in river sediments

The sediment environment provides habitat for fauna and flora. As pollutants can interchange between water and sediments, pollution will exert a significant influence on the water environment. Previous studies on polycyclic aromatic hydrocarbon (PAHs) pollution of sediments have primarily focused on the comparison of concentrations between seasons, land uses and species. Studies on the identification of the hierarchy of factors which influence PAHs distribution and its variability in river sediments are limited. This paper discusses a comprehensive investigation into the inherent variability of PAHs in sediments and the primary factors which influence this variability. The study outcomes confirmed that key factors exerting influence on PAH distribution in sediments can be ranked in the order: land use > population > seasons. Accordingly, intensive urban land use was identified as the most important factor influencing PAHs distribution. Additionally, it was found that with increasing urban development, PAHs concentrations and their variability in sediments increase in terms of the molecular weight of different species. The study outcomes are expected to enhance management strategies to mitigate PAHs pollution of urban water environments including the prioritisation of factors requiring management and the selection of appropriate approaches in the context of cost-effectiveness