Determination of parabens and triclosan in indoor dust using matrix solid-phase dispersion and gas chromatography with tandem mass spectrometry

A simple sample preparation method for the determination of four parabens and triclosan in indoor dust is presented. Analytes were extracted from the sample and isolated from interfering species using the matrix solid-phase dispersion technique. After that, they were silylated and determined by gas chromatography combined to tandem mass spectrometry (GC/MS/MS). The influence of several factors on the yield and selectivity of the extraction was evaluated in detail. Under final working conditions, samples (0.5 g) were mixed with the same amount of anhydrous sodium sulfate and dispersed on 1.25 g of C18. This blend was transferred to the top of a polypropylene cartridge containing 2 g of Florisil. After removing less polar species with 10 mL of dichloromethane, analytes were recovered using 10 mL of acetonitrile. This extract was concentrated to 1 mL, derivatized, and injected in the GC/MS/MS system. Derivatization was carried out at 45 degrees C in 5 min using 100 microL of N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide. Quantification limits from 0.6 to 2.6 ng/g and absolute recoveries between 80 and 114% were achieved. Analysis of dust samples demonstrated the presence of the target species in indoor dust from private houses. The highest average concentration (702 ng/g) corresponded to triclosan.     

The assessment of risk caused by domino effect in quantitative area risk analysis

A systematic procedure for the quantitative assessment of the risk caused by domino effect was developed. Escalation vectors, defined as the physical effects responsible of possible accident propagation, were identified for the primary scenarios usually considered in the QRA procedure. Starting from the assessment of the escalation vectors, the methodology allows the identification of credible domino scenarios and the estimation of their expected severity. A simplified technique was introduced for consequence and vulnerability assessment of domino scenarios. The overall contribution of domino effect to individual risk, societal risk and to the potential life loss index was calculated by a specific procedure, taking into account all the credible combinations of secondary events that may be triggered by each primary scenario. The development of a software package allowed the application of the procedure to several case-studies. The results evidenced the relevant modifications of the risk indexes caused by domino effect and the importance of including the quantitative analysis of domino effect in QRA, in order to correctly assess and control the risk caused by escalation scenarios.     

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.     

Combining mechanistic best-estimate analysis and level 1 probabilistic risk assessment

Traditionally, both deterministic and probabilistic methods have been used in the safety analysis of nuclear reactors. Both of these methods have evolved in recent years to a more sophisticated treatment of uncertainties in the anallyis. In particular, deterministic analysts have moved away from the traditional conservative methods to best-estimate techniques that attempt to account for uncertainties in all phases of the calculations. Because of this, a tighter and more formal coupling between the deterministic and probabilistic methods has become possible. This paper introduces a formal methodology for such combination, presents an illustrative example, and discusses a new technique for deriving acceptance criteria for deterministic analyses based on probabilistic considerations.     

The analysis of accident precursors and near misses: Implications for risk assessment and risk management

This paper presents an analysis of accident precursors or ‘near misses’ (e.g. the space shuttle flights with damaged O-rings prior to the Challenger disaster). The interpretation of such events is often problematic, since the ambiguous nature of the evidence in such cases makes them subject to widely divergent interpretations. Simple Bayesian analysis provides a resolution of this problem, showing that an accident precursor almost always justifies increased rather than decreased estimates of overall accident frequencies.     

Batteries and flow batteries-life cycle assessment in Indian conditions

Clean Technologies and Environmental Policy - The intervention of renewable energy for curbing the supply demand mismatch in power grids has projected the added advantage of having lower greenhouse...     

Modelling and quantification of dependent repeatable human errors in system analysis and risk assessment

General equations and numerical tables are developed for quantification of the probabilities of sequentially dependent repeatable human errors. Such errors are typically associated with testing, maintenance or calibration (called “pre-accident” or “pre-initiator” tasks) of redundant safety systems. Guidance is presented for incorporating dependent events in large system fault tree analysis using implicit or explicit methods. Exact relationships between these methods as well as numerical tables and simple approximate methods for system analysis are described. Analytical results are presented for a general human error model while the numerical tables are valid for a specific Handbook (THERP) model. Relationships are pointed out with earlier methods and guides proposed for error probability quantification.     

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.     

基于危险分析与风险评价的液压提升机安全设计

介绍了液压提升机的安全性能要求,对液压提升机进行了危险分析和风险评价,确定了各子系统的危险分值,得到了安全设计中必须高度关注的子系统;进行了各子系统的安全可靠度的预计与分配,并简要分析了子系统的安全设计要点,为液压提升机的安全可靠性分析与设计提供了依据。     

对危险辨识、风险评估、控制措施的实施和审核

所谓危险源是指:可能造成人员受伤或疾病等伤害的根源、状态或行为,或它们的组合.只有充分识别出危险源,正确评估和确定重要危险源,才能达到体系的控制对象明确、有的放矢.     

Nanotechnology and nanomaterials: toxicology, risk assessment, and regulations

Nanomaterials have very unique chemical and physical properties that suggest potential health hazards, but limited health and safety information exists for engineered nanomaterials. This review identifies a need for expanding efforts for addressing health and safety concerns in nanotechnology development and in nanotoxicology of engineered nanomaterials. The efforts include research to generate data for safety evaluation, toxicologic evaluation of potential human health effects, risk assessment to support risk-management decision-making, and regulations development to protect human health and the environment. The federal government's current understanding is that existing statutory authorities are adequate to address oversight of nanotechnology and its applications. On the other hand, the present review identifies weaknesses in the current research efforts and inadequacies in existing regulations. A collaborative effort involving multidisciplinary groups is a key element to address the related needs and issues. While federal agencies with regulatory responsibilities are looked upon to develop and implement sound policies and regulations to protect public health and the environment, state agencies may be required to initiate policies which rapidly incorporate new innovations and address public concerns. To address current and futures need related to nanotechnology, the responsible state agencies need to fill the information gaps and address the health and environmental issues. In California, activities have been initiated, but legislative authority and resources are required to provide risk assessment and health protection in an efficient and timely manner.     

Facts and values in risk assessment

Risk, as commonly understood, is a complex melange of facts, values, and fears. While this complexity of public risk perception is now broadly recognized, its implications are insufficiently explored. Public risk perceptions offer p poor guide for public policymaking. Popular assessments of risk are tainted by misinformation and unreliable heuristics. While subjective considerations, often called values, play a role in public perception of risk, those ‘values’ are often inappropriate for government decisionmaking. Reliance on public perceptions of risk means more premature deaths. Public risk perception also is systematically skewed contrary to the interests of the disadvantaged. Strict probabilistic risk measures generally provide a superior guide for government regulatory policy.     

Application of risk assessment and decision analysis to the evaluation, ranking and selection of environmental remediation alternatives

A single framework integrating risk assessment and decision analysis methods for evaluating, ranking and selecting preferred remediation alternatives at a contaminated site was developed and demonstrated. The methodology used relies on stakeholder inputs throughout the entire process and employs those inputs to combine the results of multiple risk assessments to arrive at a total impact for each remediation alternative. The total impact values allow the ranking of the alternatives, which in turn, serves as the basis for deliberations among the stakeholders in order to identify the preferred alternative. Six major risk or impact categories were considered in the evaluation of the alternatives: human health and safety, environmental protection, life cycle cost, socio-economics, cultural, archeological and historical resources, and programmatic assumptions.     

Meaning and contextualisation in risk assessment

This paper presents an analysis of the construction of risk as a social process. It provides a critique of Jasanoff's ‘two cultures’ model of the risk assessment community, arguing that corresponding rhetorics serve to obscure the hybrid nature of risk. It is argued that a new perspective, based on the contextualisation of expert scientific knowledge is needed, which transcends reductionist tendencies that view risk assessment as simply about either material artefacts or social constructions. Such approaches have the potential, it is suggested, to address not only the complexity but also the moral and political dilemmas associated with a wide range of risk management problems.     

Representing context, cognition, and crew performance in a shutdown risk assessment

This paper presents a potentially practical treatment of dynamic operator-system interactions. The approach employs a dynamic event tree framework to explicitly address plant dynamics, system indications, crew-plant interactions, time available, crew cognition, errors of commission (mistakes), and multiple planning and diagnosis possibilities. The approach is applied in an analysis of a hypothesize medium break loss of coolant accident for a test reactor that occurs during plant shutdown. This transient was selected on the basis of: a significant cognitive component being present, high consequences being associated with operator actions, and the importance of event timing to scenario progression. The results presented show how quantitative risk predictions are affected by the treatment of dynamics, and demonstrate how non-proceduralized recovery actions and a number of performance shaping factors (e.g., crew experience, stress, and confidence) can be explicitly treated. Insights and lessons learned regarding the performance of a dynamic assessment are also presented.     

Substance flow analysis of parabens in Denmark complemented with a survey of presence and frequency in various commodities

Parabens are commonly used as preservatives due to anti-bactericidal and anti-fungicidal properties and they are ubiquitously present in personal care products, pharmaceuticals, food, industrial and domestic commodities. They are suspected of causing endocrine disrupting effects to aquatic organisms and adverse effects in humans and, thus, it is highly relevant to identify and quantify their sources and transportation pathways in the urban environment. Here a substance flow analysis (SFA) was performed in order to map and comprehend the substances' flow on a national basis. Many household commodities were found to contain parabens; cleaning detergents, slimy toys, and water-based paint. The presence and concentration of parabens are regulated in cosmetics and food. Use of parabens in pharmaceuticals as excipients is documented in Denmark. The import of parabens is increasing; although the number of industrial parabens containing commodities is decreasing and manufacturer reports phase-out of parabens. The vast majority of the paraben containing commodities has a durability of 18-30 months, thus the average lifetime of the paraben stock is perceived to be limited. The inflow was ca. 154 tonnes via pure chemicals and 7.2-73 tonnes via commodities in 2004. This corresponds to an average wastewater concentration of 640-900 microg/L, when excluding discharge to solid waste, soil, biodegradation and metabolism. This is in the same order of magnitudes as can be found in industrial wastewater but higher than that seen in domestic wastewater. The data needed for the SFA is sparse, dispersed, and difficult to access and associated with a great deal of uncertainty.     

Illustration of integrating mechanistic best-estimate analysis results in Level 1 probabilistic risk assessment

This paper contains an illustrative application of the Ref. 1 methodology for integrating mechanistic best-estimate analysis results in Level 1 probabilistic risk assessment (PRA). Predicated upon that application the paper addresses whether the methodology can be implemented in a cost-effective manner, and whether implementation is important for improving risk quantification.     

Leaching of contaminants from untreated pine bark in a batch study: chemical analysis and ecotoxicological evaluation

Low cost sorbents have been widely studied in recent years in the search for filter materials that retain contaminants from water. One promising, low cost material is pine bark, a by-product from the forest industry. Many studies have shown that pine bark has great potential for the treatment of metals and organic substances, as a replacement for other commercial sorbents such as active carbon. However, some potential problems are introduced through the use of natural materials and by-products. One such problem that must be addressed is the possibility of leaching of contaminants from the filter material, especially in the initial filtration step or during flushes of lightly contaminated water, e.g. during rainfall for on-site treatment of storm water or landfill leachate. The aim of this preliminary study was therefore to identify potential risks and limitations of using pine bark as a filter material. Leachate from a standardized batch test was analysed for metals, dissolved organic carbon (DOC) and phenols. In addition to these chemical analyses, an ecotoxicological test was conducted using the test organism Daphnia magna. The results showed significant leaching of DOC and some metals. Only a small fraction of the DOC was present as phenols. The leachate was however found to be toxic to the test organism without pH adjustment, and the EC(50) was established at an approximate leachate concentration of 40%. This was concluded to be related to the low pH in the eluate, since no toxicity was observed after pH adjustment before the toxicity tests.     

Distribution, correlation and risk assessment of selected metals in urban soils from Islamabad, Pakistan

Urban soil samples were analyzed for Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb, Sr and Zn by atomic absorption spectrophotometric method. Multivariate statistical approach was used to study the apportionment of selected metals in the soil samples during summer and winter. The degree of contamination along with the geoaccumulation index, enrichment factor and contamination factor was also evaluated. In water-extract of the soil samples, relatively higher levels were noted for Na, Ca, K, Fe, Mg, and Pb with average concentrations of 56.38, 33.82, 12.53, 7.127, 5.994, and 1.045 mg/kg during summer, while the mean metal levels during winter were 76.45, 38.05, 3.928, 0.627, 8.726, and 0.878 mg/kg, respectively. In case of acid-extract of the soils, Ca, Fe, Mg, Na, K, Mn and Sr were found at 27,531, 12,784, 2769, 999.9, 737.9, 393.5, and 115.1 mg/kg, during summer and 23,386, 3958, 3206, 254.6, 1511, 453.6, and 53.30 mg/kg, during winter, respectively. Most of the metals showed random distribution with diverse correlations in both seasons. Principal component analysis and cluster analysis revealed significant anthropogenic intrusions of Cd, Pb, Co, Cr, Cu, Li, Zn and Na in the soils. Geoaccumulation indices and contamination factors indicated moderate to heavy contamination for Pb and Cd in the soils, while enrichment factor exhibited significant enrichment (EF > 5) of Cd, Pb, Ca, Co, Li, Mn and Zn by anthropogenic activities. Overall, on the average basis, considerable degree of contamination (C_deg > 16) was observed in both seasons, although it was higher in winter. Present metal levels were also compared with those reported from other areas around the world.