Hazard Assessment Techniques Research Articles

Probabilistic ecological hazard assessment of parabens using Daphnia magna and Pimephales promelas

Parabens are common antimicrobial agents found in thousands of pharmaceuticals and personal care products. Parabens are introduced into aquatic ecosystems from wastewater treatment plant effluents and have been detected in surface waters in the low microgram per liter range. Although these compounds display low toxicity in mammals, paraben toxicity to aquatic organisms has not been investigated. Standardized acute and subchronic endpoints in larval fish (Pimephales promelas) and cladoceran (Daphnia magna) models were examined for seven different parabens (methyl-, ethyl-, isopropyl-, propyl-, isobutyl-, butyl-, benzylparaben), which encompassed a range of log P values. Paraben 48 h median lethal concentration values (LC50) ranged from 4.0 to 24.6 mg/L in D. magna and 3.3 to >160.0 mg/L in fathead minnow. Growth and reproduction in D. magna had lowest-observed-effect concentrations (LOECs) ranging from 0.12 to 9.0 mg/L and 1.5 to 6.0 mg/L, respectively. Fathead minnow growth was adversely affected at levels ranging from 1.0 to 25.0 mg/L. Aquatic toxicity of the parabens was inversely related to lipophilicity, suggesting that responses using standardized endpoints resulted from narcosis. Utilizing toxicity benchmark concentrations (e.g., LC50s, LOECs) for each compound, chemical toxicity distributions, a probabilistic hazard assessment technique, were developed to assess the probabilities of detecting parabens that elicit a response at or below a given concentration. For the responses assessed in the present study, the 5th centile values (the concentration at which 5% of parabens elicit a response) ranged from 15 microg/L to 2.43 mg/L, with D. magna growth eliciting the lowest 5th centile value and acute D. magna mortality eliciting the highest. The distributions demonstrated that at environmentally relevant concentrations in developed countries there is limited acute or subchronic aquatic hazard of parabens to the organisms and responses examined.

Probabilistic tsunami hazard assessment at Seaside, Oregon, for near‐ and far‐field seismic sources

The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100‐ and 500‐year maximum tsunami amplitudes, i.e., amplitudes with 1% and 0.2% annual probability of exceedance. The 100‐year tsunami is generated most frequently by far‐field sources in the Alaska‐Aleutian Subduction Zone and is characterized by maximum amplitudes that do not exceed 4 m, with an inland extent of less than 500 m. In contrast, the 500‐year tsunami is dominated by local sources in the Cascadia Subduction Zone and is characterized by maximum amplitudes in excess of 10 m and an inland extent of more than 1 km. The primary sources of uncertainty in these results include those associated with interevent time estimates, modeling of background sea level, and accounting for temporal changes in bathymetry and topography. Nonetheless, PTHA represents an important contribution to tsunami hazard assessment techniques; viewed in the broader context of risk analysis, PTHA provides a method for quantifying estimates of the likelihood and severity of the tsunami hazard, which can then be combined with vulnerability and exposure to yield estimates of tsunami risk.

Hazard assessment for the safe storage, manufacturing and handling of flash compositions

Fireworks manufacturing in India is generally carried out manually due to sensitive nature of the chemical mixtures to thermal, mechanical and electrical hazards. Despite extreme care accidents continue to record leading to fatalities and complete destruction of the facility. Since there are no piping and instrumentation diagrams, it becomes difficult to apply the conventional hazard assessment techniques like HAZOP, FTA, and FMEA. In this work, for the first time one of the well-known hazard identification procedures called “what-if analysis” was used to identify hazards in a typical firework manufacturing facility. Such methodical analysis helped to identify conditions that can lead to an accident situation. This paper discusses many necessary safety precautions to be followed in the manufacture of flash compositions.

Two-dimensional resonances in Alpine valleys identified from ambient vibration wavefields

Although numerical simulations have for long shown the importance of 2-D resonances in site effect estimations of sediment-filled valleys, this phenomenon is usually not taken into account by current hazard assessment techniques. We present an approach to identify the resonance behaviour of a typical Alpine valley by analysis of ambient noise recorded simultaneously on a dense array. The applicability of the method is evaluated further using synthetic ambient noise acquired with current 3-D numerical simulation techniques. Resonance frequencies of the fundamental mode SV and the fundamental and first higher mode of SH are identified from measured data with the reference station method, verifying results of previous studies. Patterns of spectral amplitude and phase behaviour obtained from observed and synthetic noise correlate well with properties expected for 2-D resonance. Application of a frequency-wavenumber technique shows that the noise wavefield is dominated by standing waves at low frequencies (0.25 to 0.50 Hz). The different 2-D resonance modes are creating prominent peaks in horizontal-to-vertical spectral ratios, which can not be interpreted in terms of 1-D resonance. We conclude that ambient noise records measured simultaneously on a linear array perpendicular to the valley axis may be used for identification of resonance modes in sediment-filled valleys.

Soil pH, oxygen availability, and the rate of sulfide oxidation in acid sulfate soil materials: implications for environmental hazard assessment

The potential environmental hazard of acid sulfate soil (ASS) materials is directly related to both the net acidity and the rate that actual acidity is released from these soil materials into the environment. While current environmental hazard assessment techniques for ASS materials are able to quantify the net acidity, they do not take account of differences in the rate of sulfide oxidation (the dominant source of actual acidity) and differences in the rate of acidification. In this study the rate of sulfide oxidation during incubation was examined for 4 ASS materials. The effect of pH and oxygen availability on the rate of sulfide oxidation was assessed. The ASS materials were incubated in: (i) gauze where oxygen diffusion was not restricted, and (ii) sealed 100-µm-thick plastic bags which greatly limited oxygen diffusion. When oxygen diffusion was not restricted, an accelerated oxidation of sulfide occurred when the pH decreased below pH 4.0. The accelerated rate of sulfide oxidation at such low pH did not occur when oxygen diffusion was limited. This study indicates that the initial pH of an ASS material is a useful additional indicator of the potential environmental hazard of an ASS material when oxygen is expected to be non-limiting, such as when ASS materials are excavated and stockpiled. The recommended action criteria need to be reassessed, as the data indicate that the current criteria are conservative for alkaline and neutral ASS materials, but should be lowered for all acidic ASS materials (i.e. pH <5.5) to 0.03% sulfide regardless of texture.

Development of GIS-based geological hazard information system and its application for landslide analysis in Korea

Techniques for geological hazard management, assessment and prediction must be developed for the prevention and mitigation of geological hazards. To enable this, data sets related to geological hazard prevention related must be constructed, analyzed and distributed to customers. For this, a spatial database (SDB) including geological hazards, basic maps, damageable objects, satellite imagery, meteorological data and terrain analysis data was constructed using GIS, and to manage the SDB, a geological hazard information system (GHIS) was developed. The SDB is covering most area of South Korea and was formed at national, regional and medium scales separately in the form of index and administrative district unit. Using the GHIS, the SDB can be selected according to scale, locality and different types of data, and can be edited and manipulated. For the application of the constructed SDB, landslide hazard was analyzed for the Janghung area, Korea. Landslide susceptibility was analyzed using the landslide-occurrence factors by frequency ratio model. For the verification, the result of the analysis was applied to study areas. The verification results showed satisfactory agreement between the susceptibility map and the existing data on landslide locations.

Identifying potential marine pests—a deductive approach applied to Australia

Introduced marine organisms continue to threaten coastal resources around the world. Many agencies rely on lists of potentially harmful species for risk assessment and to prioritise management responses to an incursion. This study outlines a deductive hazard assessment technique to identify potential marine pests that may arrive via ballast water and/or hull fouling. This technique is then applied in an Australian context to identify potential “next pests” for this region. An extensive literature review identified 851 introduced marine species from around the world. The following selection criteria were then applied to develop a next pest list: (a) the species has been reported in a shipping vector or has a ship-mediated invasion history; (b) the vector still exists; (c) the species is responsible for economic or environmental harm; and, (d) it is exotic to Australia or present in Australia but subject to official control. The selection criteria are transparent and consistent with other international and national biosecurity initiatives. Thirty three of the species identified in the initial literature review satisfied all four selection criteria. These species are described here together with their associated vectors and impacts.

Realistic modelling of waveforms in laterally heterogeneous anelastic media by modal summation

For urban areas where numerical modelling has been successfully compared with strong motion records, the theoretical computations of synthetic seismograms permit a detailed microzoning based on a set of possible earthquake scenarios. For areas where very limited recordings are available, the synthetic time series can be used to estimate the expected ground motion, thus leading to a pre-disaster microzonation without the need to wait for an earthquake to occur. In both cases the use of synthetic computations is necessary to overcome the fact that the so-called local site effects can be strongly dependent on the properties of the seismic source generating the seismic input. In the framework of UNESCO-IUGS-IGCP project 414, ‘Realistic Modelling of Seismic Input for Megacities and Large Urban Areas’, two deterministic approaches have been applied to several urban areas for the purpose of seismic microzoning. The two approaches, valid for anelastic media, are the hybrid technique, based on the modal-summation technique and finite differences, and the mode-coupling analytical technique. We show three examples of the application of the deterministic techniques for seismic hazard assessment at urban scale, discussing the results for the cities of Rome, Catania and Augusta (Italy). The data set of synthetic seismograms can be fruitfully used and analysed by civil engineers for design and reinforcement actions, and therefore supplies a particularly powerful, and economical, tool for the prevention aspects of Civil Defence.

Comparing heuristic landslide hazard assessment techniques using GIS in the Tirajana basin, Gran Canaria Island, Spain

As part of the EU Environment and Climate Programme's RUNOUT project dealing with the modelling of large-volume landslides, a GIS database was compiled and used to generate mass movement hazard maps at a medium scale (1:25,000) in a high-relief area in central Gran Canaria Island, Spain. The Barranco de Tirajana study area is a 49 km2 large depression that is semi-oval in plan, 11 km long and 6.5 km wide. Its base presents a very irregular topography and it is almost completely enclosed by large rock scarps, up to 350 m high, with total altitude differences reaching 1600 m from the lowest part of the Barranco de Tirajana river to the upper scarps. The Barranco de Tirajana depression is composed of a series of large landslide masses, derived from gravitational sliding of lava flow and volcanic breccia sequences. The landslides are believed to have originated during intensive erosive periods during the Quaternary, as a consequence of the rapid deepening of the central ravine. These primary large landslide bodies have undergone a number of reactivation episodes, from the Middle Pleistocene to the present, as well as retrogressive enlargement of the depression. Currently the most active processes are rockfalls, and reactivation of the landslide toe areas, due to further undercutting by the streams. In order to evaluate the present mass movement hazard, a GIS-based study was carried out using two different types of knowledge-driven approaches: a direct method and an indirect method. In the direct method very detailed geomorphological mapping was carried out, using uniquely coded polygons, which were evaluated one-by-one by an expert to assess the type and degree of hazard. The indirect method followed an indexing approach. Parameters including slope angle, landslide activity, landslide phases, material, proximity to drainage channels and reservoirs, and land use change were combined using multi-criteria evaluation techniques.

New map of earthquake hazards

After three years of compiling data from more than 500 faults and applying new hazard assessment techniques, the U.S. Geological Survey (USGS) has produced new seismic hazard maps for the continental United States. The map shown here provides estimates of earthquake ground accelerations (as a percentage of g, the acceleration of a falling object due to gravity) having a 10% probability of being exceeded in 50 years. The map is based on seismicity and fault‐slip rates, and it accounts for the frequency of occurrence of earthquakes of various magnitudes. According to the USGS and the California Department of Conservation, which collaborated on a joint hazard assessment for California, more than 70% of California's population lives in an area where high levels of ground shaking could occur in the next 50 years.

Bayesian techniques for seismic hazard assessment using imprecise data

Some Bayesian methods of dealing with inaccurate or vague data are introduced in the framework of seismic hazard assessment. Inaccurate data affected by heterogeneous errors are modeled by a probability distribution instead of the usual value plus a random error representation; these data are generically called imprecise. The earthquake size and the number of events in a certain time are modeled as imprecise data. Imprecise data allow us to introduce into the estimation procedures the uncertainty inherent in the inaccuracy and heterogeneity of the measuring systems from which the data were obtained. The problem of estimating the parameter of a Poisson process is shown to be feasible by the use of Bayesian techniques and imprecise data. This background technique can be applied to a general problem of seismic hazard estimation. Initially, data in a regional earthquake catalog are assumed imprecise both in size and location (i.e errors in the epicenter or spreading over a given source). By means of scattered attenuation laws, the regional catalog can be translated into a so-called site catalog of imprecise events. The site catalog is then used to estimate return periods or occurrence probabilities, taking into account all sources of uncertainty. Special attention is paid to ‘priors’ in the Bayesian estimation. They can be used to introduce additional information as well as scattered frequency-size laws for local events. A simple example is presented to illustrate the capabilities of this methodology.

Earthquake Hazard Assessment: Has Our Approach Been Modified in the Light of Recent Earthquakes?

This may be an historic event for many of you. It will be the first time that you have ever heard a geologist give a talk related to earthquakes that was not replete with Kodachrome slides of cracks in the ground and maps of active faults, or at least of allegedly active faults, or potentially active faults or even possibly active faults! But I would like to go beyond the detailed discussion of individual earthquakes this afternoon, and instead discuss the broader problem of whether our studies of numerous recent earthquakes -- here and abroad -- are leading to modifications in our hazard assessment techniques, speaking from the point of view of a geologist or seismologist. I emphasize that I make no pretext of speaking for either the geotechnical or structural engineers. You already know, of course, the answer posed by the title. It's both yes and no. And I would like to focus on the question of: In what scientific areas, in particular, are our approaches changing, and in what areas do the traditional methods remain credible?

Hazard Assessment of a Nitration Plant using Fault Tree Analysis

Hazard assessment techniques, namely, fault tree analysis and safety analysis, have been applied to the nitration section of a plant producing explosives in the defence sector. Critical components and operations, the failure of which could lead to the occurrence of an unwanted event, have been identified and their effects quantitatively assessed. Some remedial measures have been suggested to minimise potential hazards and the effect of incorporating these measures on the system safety has been examined by means of specific case studies.

Risk assessment and the safety of large cryogenic systems and plant in the UK and Europe

The UK Health and Safety Executive (HSE) has recently published definitive guidance on the use of quantified risk assessment in decision making. This paper reviews that guidance with respect to major chemical industrial hazards (with particular reference to large scale cryogenic systems and plant) in the context of UK and European controls over such hazards and risks. The application of relevant hazard and risk assessment techniques is discussed and illustrated, with an exemplar study involving cryogenic storage of liquefied toxic gas. The example also discusses the implications for land use planning control of certain changes in plant and procedures to illustrate HSE's use of tolerability criteria in the context of such siting controls.

Major hazards in the chemical industry. Part III. A retrospective view

The contents of Parts I and II, published 14 years ago, are briefly reviewed. Development of knowledge and procedures for the control of major hazard incidents, plus some significant lessons during the intervening period, are discussed. Trends in legislation are summarised and consideration is given to the concept of environmental, transport, and off-shore major hazards. Quantitative hazard and risk assessment techniques are referred to. The purpose of the paper is to contribute through the journal to the ongoing debate on Major Hazards; it is not intended to be a criticism of progress that has been made to-date, or of work in hand. Illustrative cameo case histories are included to relate theory and practice.

Stochastic prediction techniques for wind shear hazard assessment

The threat of low-altitude wind shear has prompted development of aircraft-based sensors that measure winds directly on the aircraft's intended flight path. Measurements from these devices are subject to turbulence inputs and measurement error, as well as to the underlying wind profile. Stochastic estimators are developed to process on-board Doppler sensor measurements, producing optimal estimates of the winds along the path. A stochastic prediction technique is described to predict the hazard to the aircraft from the estimates as well as the level of uncertainty of the hazard prediction. The stochastic prediction technique is demonstrated in a simulated microburst wind shear environment. Use of the technique in a decision-making process is discussed. >

Mode of action and the assessment of chemical hazards in the presence of limited data: use of structure-activity relationships (SAR) under TSCA, Section 5.

Section 5 of the Toxic Substances Control Act (TSCA) requires that manufacturers and importers of new chemicals must submit a Premanufacture Notification (PMN) to the U.S. Environmental Protection Agency 90 days before they intend to commence manufacture or import. Certain information such as chemical identity, uses, etc., must be included in the notification. The submission of test data on the new substance, however, is not required, although any available health and environmental information must be provided. Nonetheless, over half of all PMNs submitted to the agency do not contain any test data; because PMN chemicals are new, no test data is generally available in the scientific literature. Given this situation, EPA has had to develop techniques for hazard assessment that can be used in the presence of limited test data. EPA's approach has been termed "structure-activity relationships" (SAR) and involves three major components: the first is critical evaluation and interpretation of available toxicity data on the chemical; the second component involves evaluation of test data available on analogous substances and/or potential metabolites; and the third component involves the use of mathematical expressions for biological activity known as "quantitative structure-activity relationships" (QSARs). At present, the use of QSARs is limited to estimating physical chemical properties, environmental toxicity, and bioconcentration factors. An important overarching element in EPA's approach is the experience and judgment of scientific assessors in interpreting and integrating the available data and information. Examples are provided that illustrate EPA's approach to hazard assessment for PMN chemicals.

Dealing with the process safety “management gap”

AbstractThe Process Industry has Corporate Safety Policies, codes of practice, skilled engineers and safety specialists and powerful techniques for Hazard Identification, Assessment and Control. Despite the above and a strong commitment to safety, accidents still occur. Many accidents appear to be due to “gaps” in the management systems rather than to failures of professional skills or to a lack of commitment. This paper will review the many stages in designing, constructing and operating a facility between the initial appraisal of a potential project and the final taking out of service of a facility. The “primary” and “secondary” safety checks will be described. The paper will give examples of gaps in management systems which have led to problems. Finally the paper will suggest ways in which these gaps can be minimized.

Use of quantified risk assessment techniques in relation to major hazard installations

Over the past decade, industry and regulatory authorities have expressed interest in the development and use of hazard assessment techniques, particularly in relation to the control of major hazards. However, misconceptions about the methodology and role of quantified hazard assessment techniques in decision-making has hindered productive dialogues on the use and value of these techniques, both within industry and between industry and regulatory authorities. This Paper outlines the nature, role and current uses of hazard assessment as perceived by the author; and identifies and differentiates between those areas and types of decisions where quantification should prove beneficial, and those where it is unwarranted and should be discouraged.

Landslide hazard assessment techniques for planning purposes: a review

Abstract Recently, there has been a growing interest, both in the UK and abroad, in the use of land evaluation and hazard assessment techniques for planning purposes. Both engineering geologists and planners have become increasingly aware of the benefits to be gained from these techniques of rapid and cost-effective terrain and hazard assessment. However, the application of these techniques and the interpretation of the information they provide need clarification in order to be of direct use to planners. This paper will summarize the techniques, presently available, of land evaluation and hazard assessment and focus attention on defining the engineering geological and planning criteria that control the success with which these techniques can be used effectively. Land evaluation techniques will be considered briefly in view of the large volume of literature already available on this subject. The paper will concentrate on hazard assessment techniques whose potential has been under-utilized in the UK, particularly for planning purposes. Particular emphasis will be placed on mass movement hazards.Techniques available for evaluating these hazards include, satellite imagery, air photograph interpretation, hazard and susceptibility mapping, surface geological and geomorphological mapping, sub-surface geotechnical investigation and monitoring. These will be discussed in respect of the scale of the investigation or planning objectives and the assumptions, data requirements and interpretative capability of each technique.