Statistical analysis of atmospheric trace metals and particulate fractions in Islamabad, Pakistan

Airborne suspended particulate matter was collected on glass fibre filters in urban atmosphere of Islamabad, Pakistan, using high volume sampler. The particulate samples were analysed for 10 selected metals (Fe, Na, Zn, K, Pb, Mn, Cr, Ni, Co and Cd) by FAAS method. Maximum mean contribution was noted for Fe (1.761microg/m(3)), followed by Na (1.661microg/m(3)), Zn (1.021microg/m(3)), K (0.488microg/m(3)) and Pb (0.128microg/m(3)). The particle size determination on vol.% basis for nine fractions (PM(<1.0), PM(1.0-2.5), PM(2.5-5), PM(5-10), PM(10-15), PM(15-25), PM(25-50), PM(50-100) and PM(>100)) was carried out using Mastersizer. PM(5.0-10) were found to be most abundant in the local atmosphere followed by PM(2.5-5.0) and PM(15-25) while coarse/giant particles (PM(50-100) and PM(>100)) showed lower contribution. The trace metals were found to be mainly associated with smaller particulate fractions up to PM(10-15). Among the climatic parameters temperature has significant relationship with fine particles and airborne metal levels while relative humidity showed negative correlation. The source identification was carried out by principal component analysis and cluster analysis. Five metal sources were identified: industrial, vehicular emissions, metallurgical operations, garbage incineration and soil derived dust. The metal levels were also compared with those reported for other rural and urban parts around the world.     

Distribution and circumstances of injuries in squatter settlements of Karachi, Pakistan

OBJECTIVES: This research was conducted to study incidence, distribution, type, causes, severity and circumstances of injuries among people living in squatter settlements in Karachi, Pakistan. METHODS: Trained interviewers sought a 2 weeks recall for minor injuries for which no health care was sought, 2 months recall for major injuries for which a health provider was consulted and 1 year recall for hospitalization, disability and death from every third household in five squatter settlements in Karachi between May and August 1995. For understanding the injury circumstances 250 in-depth interviews of the injured or the close relatives were also conducted. RESULTS: Among 1182 households, having 9891 residents, 84 minor, 42 major injury episodes, 7 hospitalizations, 0.6 permanent disabilities and 0.3 deaths per 1000 person years were reported. Including all injury episodes, the common types of injury were cutting or piercing (n = 532), falls (n = 382) and burns (n = 235) estimating to 54, 38 and 23 injury episodes per 1000 person years. Injury mainly resulted from a piece of glass (n = 367), falling from height (n = 98) and knife (n = 97) estimating to 37, 10 and 10 injury episodes per 1000 person years, respectively. Fall (n = 32, 3.2/1000 person years) was the major reason for hospitalizations and all permanent disabilities resulted from closed injuries. Medically trained providers were mostly contacted (n = 339, 34/1000 person years), but traditional healers were preferred in bone injury. CONCLUSION: Injuries are a major cause of morbidity and mortality in Pakistan and the national health and development agenda should include assessment and prevention of injuries.     

Health risk assessment by measuring plasma malondialdehyde (MDA), urinary 8-hydroxydeoxyguanosine (8-OH-dG) and DNA strand breakage following metal exposure in foundry workers

Silica particles and metals are important occupational hazards in foundry workers, and exposure may result in DNA damage and lipid peroxidation through oxidative stress. This study aimed to compare oxidative damage by measuring the levels of plasma malondialdehyde (MDA), urinary 8-hydroxydeoxyguanosine (8-OH-dG) and DNA strand breakage in workers at two foundry plants (exposure group) and in town hall employees (control group) in central Taiwan. Air samples for metals analysis in the workplace were also collected to assess the health risk to foundry workers.Significantly higher MDA levels (4.28 μM versus 1.64 μM), DNA strand breakage (6.63 versus 1.22), and 8-OH-dG levels (5.00 μg/g creatinine versus 1.84 μg/g creatinine) were found in exposure group compared with the control group. Higher levels of these parameters were also found in workers involved in manufacturing than in workers involved in administration. Higher air respirable dust concentrations were found in manufacturing departments (0.99 mg/m³) than in administrative departments (0.34 mg/m³). The health risk assessment on metals exposure showed that the cancer risk for Cd, Cr and Ni were all above 1 × 10⁻⁶. Future studies are necessary to determine whether metals exposure can contribute to oxidative damage in foundry workers.     

家用车内空气苯系物污染状况及健康风险分析

调查研究了家用车内空气中苯和二甲苯的污染状况,并对其造成的健康风险进行了分析.研究发现,家用车内空气普遍存在苯系物浓度超标的现象,汽车的车龄、静态封闭时间对车内空气质量有一定影响.车内空气中苯污染对男性和女性驾乘人员造成的致癌风险分别为2.34×10-5和2.62×10-5,明显高于美国EPA对致癌物的控制标准.车内空气中苯和二甲苯造成的非致癌健康风险分别为5.23和1.72,会对人体健康产生显著影响.因此,为了保障汽车驾乘人员的身体健康,有必要采取适当的措施改善车内空气的质量.     

Multi-attribute risk assessment for risk ranking of natural gas pipelines

The paper presents a decision model for risk assessment and for risk ranking of sections of natural gas pipelines based on multi-attribute utility theory. Pipeline hazard scenarios are surveyed and the reasons for a risk assessment model based on a multi-attribute approach are presented. Three dimensions of impact and the need to translate decision-makers’ preferences into risk management decisions are highlighted. The model approaches these factors by using a multi-attribute utility function, in order to produce multi-dimensional risk measurements. By using decision analysis concepts, this model quantitatively incorporates the decision-maker's preferences and behavior regarding risk within clear and consistent risk measurements. In order to support the prioritizing of critical sections of pipeline in natural gas companies, this multi-attribute model also allows sections of pipeline to be ranked into a risk hierarchy. A numerical application based on a real case study was undertaken so that the effectiveness of the decision model could be verified.     

A critical view of severity classification in risk assessment methods

The knowledge of operational experts plays a fundamental role in performing safety assessments in safety critical organizations. The complexity and socio-technical nature of such systems produce hazardous situations which require a thorough understanding of concrete operational scenarios and cannot be anticipated by simply analysing single failures of specific functions. This paper addresses some limitations regarding state-of-the-art safety assessment techniques, with special reference to the adoption of “chain of event” models in accident causation (widely criticised by many authors), to the use of severity classes and to the adoption of the worst credible effect criterion. Such methods tend to assume a linear link between single hazards considered in isolation and corresponding consequences for safety, thus neglecting the intrinsic complexity of the systems under analysis and reducing the opportunities for an effective involvement of operational experts. An alternative approach is proposed to overcome these limitations, by distinguishing different typologies of hazards and integrating the analysis of single functions with the study of concrete operational scenarios.     

Risk assessment of heavy metals in soil previously irrigated with industrial wastewater in Shenyang, China

The Zhangshi Irrigation Area (ZIA) in Shenyang, China has been irrigated by industrial wastewater since 1962. Since then, parts of the ZIA have been rezoned for industrial uses, but the remaining area, named Sluice Gate III (SLIII) and Lower Reaches (LR), still occupies 1825ha. Although land irrigation with industrial wastewater ceased in 1992, a study on heavy metals in soils was carried out to assess the feasibility of agricultural crop cultivation in SLIII and LR. A detailed field investigation was conducted and both total heavy metal concentrations and bioavailable fraction in soil were determined. The results have highlighted that Cd concentrations in soils still exceed the Environmental Quality Standard for Soil in China (GB15618-1995) grade C standard in SLIII region, and grade B standard in LR. In the SLIII, Zn and Pb concentrations in soil are higher than the grade A standard, although Cu is close the grade A standard. In SLIII the dominant chemical fractions were the exchangeable and carbonatic forms, which represent up to 43% and 35% of the Cd, respectively. The Cd in these two fractionations poses the highest risk for the plant absorption and accumulation. Therefore the SLIII should be abandoned for cultivated crops to prevent the Cd contamination of food chain and any associated hazards to human health.     

Layer of protection analysis for reactive chemical risk assessment

Reactive chemical hazards have been a significant concern for the chemical process industries (CPI). Without sufficient control and mitigation of chemical reaction hazards, reactive incidents have led to severe consequences, such as release of flammable and toxic materials, fires and explosions, and threats to human lives, properties, and the environment. Consequence of reactive hazards can be well understood through calorimetric testing and computational techniques. However, risks of incidents caused by reactive chemicals have not been well addressed due partly to sparse failure frequency data. In this paper, the semi-quantitative layer of protection analysis (LOPA) approach is used to estimate reactive chemical risk, and the probabilities or frequencies of failure scenarios are addressed. Using LOPA, reactive risks can be evaluated with respect to predefined criteria, and the effectiveness of risk reduction measures can be assessed. The hydroxylamine (HA) production system is employed as a case study to demonstrate the application of LOPA to reactive chemical risk assessment.     

Improving pilots' risk assessment skills in low-flying operations: the role of feedback and experience

Risk assessment is one of the most important skills that pilots are expected to acquire to ensure the safe and successful management of flight. The traditional approach to the development of these skills requires pilots to directly engage with potentially hazardous events. Using low-flying as a context, the present study sought to test whether engagement with hazards in a simulated environment, together with feedback concerning performance, would improve pilots' risk assessment during a subsequent simulated test flight. The results indicated that engagement with the hazards, rather than the provision of feedback per se, was associated with behavior that reduced the risk to the aircraft, while maintaining operational performance. It was concluded that exposure to hazards within a simulated environment could provide the basis for the development of risk assessment skills amongst less experienced pilots.     

Some considerations on the treatment of uncertainties in risk assessment for practical decision making

This paper discusses the challenges involved in the representation and treatment of uncertainties in risk assessment, taking the point of view of its use in support to decision making. Two main issues are addressed: (1) how to faithfully represent and express the knowledge available to best support the decision making and (2) how to best inform the decision maker. A general risk-uncertainty framework is presented which provides definitions and interpretations of the key concepts introduced. The framework covers probability theory as well as alternative representations of uncertainty, including interval probability, possibility and evidence theory.     

Human factors, human reliability and risk assessment in license renewal of a nuclear power plant

This paper describes human factors and human reliability assessments carried out as a part of operating license renewal of a nuclear power plant. The structure and contents of human factors assessments, the source material and the role of probabilistic safety assessment are described. Similar evaluations are recommended as an integral part of periodic safety reviews of regulated industrial facilities.The qualitative part of the human factors review is structured according to an international guide. The assessments are here enhanced with operating experience evaluations, measured by quantitative statistical data obtained from inspections and assessments made by plant safety and quality assurance personnel, by regulatory authorities and by peer reviews.The quantitative assessment is based on the roles and contributions of human errors in the accident risk of the target plant. The assessment uses importance measures quantified in probabilistic risk assessment. The scope and the quality of the risk assessment and the scope and the quality of human reliability assessments are also taken into account. Furthermore, the assessment describes how risk assessment can be used to reduce errors and improve human factors. The results tend to be very plant-specific, and the errors have very different importances in different operating states and for different initiating event categories. The results are useful for planning preventive actions, i.e. for preventing errors by developing and prioritizing human factors improvement activities.     

Pipeline risk assessment and risk acceptance criteria in the State of Sao Paulo,Brazil

This paper reviews the current framework for, and practical application of, environmental impact assessment (EIA) in Malaysia and assesses the progress made towards adoption of strategic environmental assessment (SEA). EIA legislation was first introduced in 1987 and much progress has been made in enforcing compliance with the requirements. More recent moves towards devolution of EIA control to the states are an indicator of the influence that EIA is making, although there are still many practical constraints to be overcome. Even more recently, Malaysia has used SEA for area-wide schemes: the potential for this take up is evaluated. Despite many problems, the EIA process continues to function and evidence of an emerging commitment to SEA bodes well for the future.     

Degradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils by Fenton's reagent: a multivariate evaluation of the importance of soil characteristics and PAH properties

In this study, we investigated how the chemical degradability of polycyclic aromatic hydrocarbons (PAHs) in aged soil samples from various contaminated sites is influenced by soil characteristics and by PAH physico-chemical properties. The results were evaluated using the multivariate statistical tool, partial least squares projections to latent structures (PLS). The PAH-contaminated soil samples were characterised (by pH, conductivity, organic matter content, oxide content, particle size, specific surface area, and the time elapsed since the contamination events, i.e. age), and subjected to relatively mild, slurry-phase Fenton's reaction conditions. In general, low molecular weight PAHs were degraded to a greater extent than large, highly hydrophobic variants. Anthracene, benzo(a)pyrene, and pyrene were more susceptible to degradation than other, structurally similar, PAHs; an effect attributed to the known susceptibility of these compounds to reactions with hydroxyl radicals. The presence of organic matter and the specific surface area of the soil were clearly negatively correlated with the degradation of bi- and tri-cyclic PAHs, whereas the amount of degraded organic matter correlated positively with the degradation of PAHs with five or six fused rings. This was explained by enhanced availability of the larger PAHs, which were released from the organic matter as it degraded. Our study shows that sorption of PAHs is influenced by a combination of soil characteristics and physico-chemical properties of individual PAHs. Multivariate statistical tools have great potential for assessing the relative importance of these parameters.     

Quality of the guidelines for preparation and review of environmental impact assessment reports in Pakistan

Environmental impact assessment (EIA) is an important tool for making informed decisions about development projects to avoid or mitigate potential adverse impacts on the environment. Guidelines are prepared all over the world to facilitate consultants and stakeholders to meet the objectives of EIA and to prepare quality EIA reports. The Pakistan Environmental Protection Agency prepared environmental impact assessment guidelines for this purpose in 1997. However, the major issue is that, even after two decades, the guidelines have not been reviewed. This paper presents the outcome of research conducted on the contents and quality of the guidelines for the preparation of EIA reports. The methodology encompasses an extensive review of the literature as well as available guidelines and interviews with the selected consultants, using semi-structured interview schedules. Although the quality of current guidelines overall is found to be good, the likelihood they are followed is connected with them being updated regularly, taking on board opinion of EIA consultants and other stakeholders.     

Comparison between electrocoagulation and chemical precipitation for metals removal from acidic soil leachate

This paper provides a quantitative comparison between electrocoagulation and chemical precipitation based on heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) removal from acidic soil leachate (ASL) at the laboratory pilot scale. Chemical precipitation was evaluated using either calcium hydroxide or sodium hydroxide, whereas electrocoagulation was evaluated via an electrolytic cell using mild steel electrodes. Chemical precipitation was as effective as electrocoagulation in removing metals from ASL having low contamination levels (30 mg Pbl(-1) and 18 mg Znl(-1)). For ASL enriched with different metals (each concentration of metals was initially adjusted to 100 mg l(-1)), the residual Cr, Cu, Pb and Zn concentrations at the end of the experiments were below the acceptable level recommended for discharge in sewage urban works (more than 99.8% of metal was removed) using either electrocoagulation or chemical precipitation. Cd was more effectively removed by electrochemical treatment, whereas Ni was easily removed by chemical treatment. The cost for energy, chemicals and disposal of metallic residue of electrocoagulation process ranged from USD 8.83 to 13.95 tds(-1), which was up to five times lower than that recorded using chemical precipitation. Highly effective electrocoagulation was observed as the ASL was specifically enriched with high concentration of Pb (250-2000 mg Pbl(-1)). More than 99.5% of Pb was removed regardless of the initial Pb concentration imposed in ASL and, in all cases, the residual Pb concentrations (0.0-1.44 mg l(-1)) were below the limiting value (2.0 mg l(-1)) for effluent discharge in sewage works.     

A multimedia, multiple pathway risk assessment of atrazine: the impact of age differentiated exposure including joint uncertainty and variability

This paper addresses the need to evaluate the differences in exposure to pesticides between children and adults. We present a framework for evaluating these differences in exposure to pesticides through multiple exposure pathways. The concentrations in all environmental media were determined as distributions in a companion paper. All parameter values utilized in the calculation of exposure and risk are considered to be distributions, resulting in distributions for output exposure and risk. A sensitivity analysis was completed to determine the relative importance of the parameters with respect to the outcome. A joint uncertainty and variability analysis was also completed to evaluate the relative contribution between uncertain and variable parameters. Exposure to atrazine by a mid-western farming family is presented as a case study. The predicted exposure for a child based on a 14-year exposure period was 1.6 times that calculated using lifetime averaged exposure parameters. This indicates the importance of considering children as a population sub-group when calculating the exposure and risk to pesticides.     

An aftermath analysis of the 2014 coal mine accident in Soma,Turkey: Use of risk performance indicators based on historical experience

On the 13th of May 2014 a fire related incident in the Soma coal mine in Turkey caused 301 fatalities and more than 80 injuries. This has been the largest coal mine accident in Turkey, and in the OECD country group, so far. This study investigated if such a disastrous event should be expected, in a statistical sense, based on historical observations. For this purpose, PSI's ENSAD database is used to extract accident data for the period 1970–2014. Four different cases are analyzed, i.e., OECD, OECD w/o Turkey, Turkey and USA. Analysis of temporal trends for annual numbers of accidents and fatalities indicated a non-significant decreasing tendency for OECD and OECD w/o Turkey and a significant one for USA, whereas for Turkey both measures showed an increase over time. The expectation analysis revealed clearly that an event with the consequences of the Soma accident is rather unlikely for OECD, OECD w/o Turkey and USA. In contrast, such a severe accident has a substantially higher expectation for Turkey, i.e. it cannot be considered an extremely rare event, based on historical experience. This indicates a need for improved safety measures and stricter regulations in the Turkish coal mining sector in order to get closer to the rest of OECD.     

STRRAP system—A software for hazardous materials risk assessment and safe distances calculation

This work presents a powerful computational tool (Stochastic Toxic Release Risk Assessment Package, STRRAP) useful in risk assessment and emergency planning (safe distance calculation), which allows to handle the stochastic uncertainty of atmospheric parameters, critical for risk calculation when diffusion of hazardous gases or particulate matter occur as a consequence of an emission or accidental release. In fact, the random behaviour of wind intensity, wind direction, atmospheric stability and temperature, given a time horizon, (a season or a complete year), is taken into account considering also the day or night condition.STRRAP can be used for releases or emissions from static sources (for example a stack or a fixed tank in a facility) or from transportation accidents (road, rail, maritime and pipeline transport) involving different scenarios.After a stochastic simulation based on well-known diffusion models (dense and light gases, particulate matter) is carried out, the downwind pollutant concentrations are obtained, in order to compute safe distances and/or individual and societal risks.Some study cases are analyzed to show STRRAP capabilities.     

Tissue metal concentrations and histopathology of rats gavaged with vitrified soil obtained from the former Charleston Naval Shipyard (SC,USA)

Male Sprague Dawley^® rats were administered a vitrified material obtained from the former Charleston Naval Shipyard (Charleston, SC, USA) by gavage once daily for 32 days. Group mean body weight of treated animals was within ±5.4% of controls. No gross or histopathological changes were observed when animals were treated with 67, 174, or 370 mg/kg per day. Analysis of heavy metals revealed a statistically significant increase only in the concentration of arsenic in the livers of animals treated with 174 or 370 mg/kg per day versus controls. Although there was a statistically significant increase in liver arsenic levels, the concentrations were far below mean soil concentrations for western and eastern United States. If the standard assumption of 100% absorption is used, the concentrations observed in the present study are about 20 times less than the average background soil levels in these regions. Based on this, it is concluded that the vitrified material would not pose a public health risk for its intended use as an additive for asphalt and glass beams.     

CDF sensitivity analysis technique for ranking influential parameters in the performance assessment of the proposed high-level waste repository at Yucca Mountain, Nevada, USA

A cumulative distribution function (CDF)-based method has been used to perform sensitivity analysis on a computer model that conducts total system performance assessment of the proposed high-level nuclear waste repository at Yucca Mountain, and to identify the most influential input parameters affecting the output of the model. The performance assessment computer model referred to as the TPA code, was recently developed by the US nuclear regulatory commission (NRC) and the center for nuclear waste regulatory analyses (CNWRA), to evaluate the performance assessments conducted by the US department of energy (DOE) in support of their license application. The model uses a probabilistic framework implemented through Monte Carlo or Latin hypercube sampling (LHS) to permit the propagation of uncertainties associated with model parameters, conceptual models, and future system states. The problem involves more than 246 uncertain parameters (also referred to as random variables) of which the ones that have significant influence on the response or the uncertainty of the response must be identified and ranked. The CDF-based approach identifies and ranks important parameters based on the sensitivity of the response CDF to the input parameter distributions. Based on a reliability sensitivity concept [AIAA Journal 32 (1994) 1717], the response CDF is defined as the integral of the joint probability-density-function of the input parameters, with a domain of integration that is defined by a subset of the samples. The sensitivity analysis does not require explicit knowledge of any specific relationship between the response and the input parameters, and the sensitivity is dependent upon the magnitude of the response. The method allows for calculating sensitivity over a wide range of the response and is not limited to the mean value.