Risk-relevant indices for the characterization of persistence of chemicals in a multimedia environment

The present research study proposes a new set of appropriately defined indices for the characterization of persistence of chemicals in a multimedia environment that prominently figures as a key exposure-based indicator within contemporary frameworks of chemical hazard and risk assessment, as well as recent international regulatory initiatives. Effectively overcoming some of the limitations associated with traditional approaches that could lead to a potential misclassification of chemical substances, the proposed set of persistence indices retain also a conceptually insightful and computational appeal. Conceptually inspired by certain measures/indices for the characteristic time found in classic dynamic systems theory, and technically relying on notions and methods from the theory of matrices, the new performance indices can be easily calculated on the basis of a dynamic multimedia environmental model and the aid of a software package such as MATLAB. In particular, an extension of the notion of equivalence width as a quantitative proxy of overall persistence is introduced, that captures the dynamic history of the chemical's environmental behavior, while remaining independent of the particular release pattern and discharge conditions (thus overcoming the standardization difficulties encountered when a large number of chemicals need to be first screened and classified in a tiered hazard assessment methodology). Furthermore, a second persistence index is introduced whose value can be analytically calculated through the solution of a simple Lyapunov matrix equation bearing some resemblance to certain measures of system resilience used in theoretical biology and ecology, yet inspired by system-theoretic notions associated with the Lyapunov framework of analysis in systems science. Furthermore, for both persistence measures a comparison is made with the slowest time-constant associated with the specific chemical dynamics in a multimedia environment, and upper and lower bounds are established. Finally, the proposed persistence indices are calculated on the basis of a standard dynamic multimedia environmental model for various representative cases involving chemicals of particular interest.     

GIS-based modelling for the estimation of municipal solid waste generation and collection

In the present paper, an innovative model for the estimation of municipal solid waste generation and collection is proposed. This model is part of an extended solid waste management system and uses a spatial Geodatabase, integrated in a GIS environment. It takes into consideration several parameters of waste generation, such as population density, commercial activities, road characteristics and their influence on the location and allocation of waste bins. Ground-based analysis was applied for the estimation of the inter-relations between the aforementioned factors and the variations in waste generation between residential and commercial areas. Therefore, the proposed model follows a unified categorization approach for residential and commercial activities and focuses on the dominant factors that determine waste generation in the area under study. The most important result of the research work presented in the current paper is an accurate estimation of the optimal number of waste bins and their allocation. A new methodology and an appropriate algorithm have been developed for this purpose in order to facilitate routing and waste collection. By using these results, municipalities aware of social, economical and environmental factors, related to waste management, can achieve optimal usage of their resources and offer the best possible services to their citizens.     

MODELING FRAMEWORK FOR MANAGING COPPER RUNOFF IN URBAN WATERSHEDS1

ABSTRACT: A modeling framework was developed for managing copper runoff in urban watersheds that incorporates water quality characterization, watershed land use areas, hydrologic data, a statistical simulator, a biotic ligand binding model to characterize acute toxicity, and a statistical method for setting a watershed specific copper loading. The modeling framework is driven by export coefficients derived from water quality parameters and hydrologic inputs measured in an urban watershed's storm water system. This framework was applied to a watershed containing a copper roof built in 1992. A series of simulations was run to predict the change in receiving stream water chemistry caused by roof aging and to determine the maximum copper loading (at the 99 percent confidence level) a watershed could accept without causing acute toxicity in the receiving stream. Forecasting the amount of copper flux responsible for exceeding the assimilation capacity of a watershed can be directly related to maximum copper loadings responsible for causing toxicity in the receiving streams. The framework developed in this study can be used to evaluate copper utilization in urban watersheds.     

Nutrient mitigation in a temporary river basin

We estimate the nutrient budget in a temporary Mediterranean river basin. We use field monitoring and modelling tools to estimate nutrient sources and transfer in both high and low flow conditions. Inverse modelling by the help of PHREEQC model validated the hypothesis of a losing stream during the dry period. Soil and Water Assessment Tool model captured the water quality of the basin. The ‘total daily maximum load’ approach is used to estimate the nutrient flux status by flow class, indicating that almost 60 % of the river network fails to meet nitrogen criteria and 50 % phosphate criteria. We recommend that existing well-documented remediation measures such as reforestation of the riparian area or composting of food process biosolids should be implemented to achieve load reduction in close conjunction with social needs.     

Integration & assessment of recycling into c-Si photovoltaic module’s life cycle

Photovoltaic (PV) energy generation devices have experienced a vigorous growth in production over the last decade in all major industrialised countries. In this research paper, the assessment of recycling and subsequent production of new crystalline silicon (c-Si) PV modules taking advantage of the recovered Si in terms of industrial symbiosis is being examined. With the aid of life cycle analysis method, the potential payback is thoroughly examined through a scenario application in the second useful phase of the PV module. Furthermore, key environmental performance indicators have been implemented in order to evaluate power and resource demands.     

From chemical risk assessment to environmental resources management: the challenge for mining

On top of significant improvements and progress made through science and engineering in the last century to increase efficiency and reduce impacts of mining to the environment, risk assessment has an important role to play in further reducing such impacts and preventing and mitigating risks. This paper reflects on how risk assessment can improve planning, monitoring and management in mining and mineral processing operations focusing on the importance of better understanding source–pathway–receptor linkages for all stages of mining. However, in light of the ever-growing consumption and demand for raw materials from mining, the need to manage environmental resources more sustainably is becoming increasingly important. The paper therefore assesses how mining can form an integral part of wider sustainable resources management, with the need for re-assessing the potential of mining in the context of sustainable management of natural capital, and with a renewed focus on its the role from a systems perspective. The need for understanding demand and pressure on resources, followed by appropriate pricing that is inclusive of all environmental costs, with new opportunities for mining in the wastes we generate, is also discussed. Findings demonstrate the need for a life cycle perspective in closing the loop between mining, production, consumption and waste generation as the way forward.     

The management of household hazardous waste in the United Kingdom

Waste legislation in the United Kingdom (UK) implements European Union (EU) Directives and Regulations. However, the term used to refer to hazardous waste generated in household or municipal situations, household hazardous waste (HHW), does not occur in UK, or EU, legislation. The EU's Hazardous Waste Directive and European Waste Catalogue are the principal legislation influencing HHW, although the waste categories described are difficult to interpret. Other legislation also have impacts on HHW definition and disposal, some of which will alter current HHW disposal practices, leading to a variety of potential consequences. This paper discusses the issues affecting the management of HHW in the UK, including the apparent absence of a HHW-specific regulatory structure. Policy and regulatory measures that influence HHW management before disposal and after disposal are considered, with particular emphasis placed on disposal to landfill.     

Hydro-geochemical aspects of Mediterranean temporary ponds in western Crete

The hydrologic and geochemical conditions that prevail in Mediterranean temporary ponds (MTPs), create a unique environment for many rare and endangered species. Mediterranean temporary ponds are habitats of high ecological value, which are vulnerable to imminent climatic changes, as well as to human activities. This article examines the hydrology and the nitrogen and phosphorous geochemical cycles of four MTPs in Crete. Field and laboratory studies provided the necessary information for the development of a conceptual understanding of the hydrologic and biogeochemical processes that affect the fate of nitrogen and phosphorous in these MTPs. Their hydrology was driven by deposition, infiltration, and evaporation. The hydroperiod of the ponds varied between 40 and 160 d. Mineralization and nutrient release capacity experiments illustrated the significant role that MTP sediments played in enhancing the geochemistry of the aqueous phase. Such ecosystem functions (i.e., mineralization, nutrient release) exhibited high variability among MTPs necessitating site-specific studies with immediate implications to management. It is very important to understand the local hydrogeochemical and climatic conditions to ensure appropriate environmental measures for their management and conservation.     

Polycyclic aromatic hydrocarbons (PAHs) reduce hepatic β-oxidation of fatty acids in chick embryos

Polycyclic aromatic hydrocarbons (PAHs) are widespread fused-ring contaminants formed during incomplete combustion of almost all kind of organic materials from both natural and anthropogenic sources. Some PAHs have been shown to be carcinogenic to humans, and a wide range of PAHs are found in wildlife all around the globe including avian species. The purpose of this project was to assess the effects of a standard mixture of 16 PAHs (United States Environmental Protection Agency) on the hepatic fatty acid β-oxidation in chicken embryos (Gallus gallus domesticus) exposed in ovo. The hepatic β-oxidation was measured using a tritium release assay with [9,10-³H]-palmitic acid (16:0) as substrate. Treated groups were divided into groups of 0.05, 0.1, 0.3, 0.5, and 0.8 mg PAHs/kg egg weight. The hepatic β-oxidation was reduced after exposure in ovo to the 16 PAHs mixture compared to control. The mechanisms causing reduced fatty acid oxidation in the present study are unclear, however may be due to deficient membrane structure, the functionality of enzymes controlling the rate of fatty acid entering into the mitochondria, or complex pathways connected to endocrine disruption. To the best of our knowledge, this is the first time a PAH-caused reduction of hepatic β-oxidation of fatty acids in avian embryos has been observed. The implication of this finding on risk assessment of PAH exposure in avian wildlife remains to be determined.     

Screening and prioritisation of chemical risks from metal mining operations, identifying exposure media of concern

Metals have been central to the development of human civilisation from the Bronze Age to modern times, although in the past, metal mining and smelting have been the cause of serious environmental pollution with the potential to harm human health. Despite problems from artisanal mining in some developing countries, modern mining to Western standards now uses the best available mining technology combined with environmental monitoring, mitigation and remediation measures to limit emissions to the environment. This paper develops risk screening and prioritisation methods previously used for contaminated land on military and civilian sites and engineering systems for the analysis and prioritisation of chemical risks from modern metal mining operations. It uses hierarchical holographic modelling and multi-criteria decision making to analyse and prioritise the risks from potentially hazardous inorganic chemical substances released by mining operations. A case study of an active platinum group metals mine in South Africa is used to demonstrate the potential of the method. This risk-based methodology for identifying, filtering and ranking mining-related environmental and human health risks can be used to identify exposure media of greatest concern to inform risk management. It also provides a practical decision-making tool for mine acquisition and helps to communicate risk to all members of mining operation teams.