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1.
Environ Sci Technol ; 45(23): 9857-65, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-22017747

RESUMEN

Policy makers and regulators are charged with the daunting task of comparing incommensurate environmental risks to inform strategic decisions on interventions. Here we present a policy-level framework intended to support strategic decision processes concerning environmental risks within the Department for Environment, Food and Rural Affairs (Defra). The framework provides the structure by which risk-based evidence may be collated and by assessing the value of harm expressed by different environmental policy areas against a consistent objective (e.g., sustainable development), we begin to form a basis for relative comparison. This research integrates the prior art, examples of best practice, and intimate end-user input to build a qualitative assessment informed by expert judgment. Supported by contextual narratives, the framework has proven successful in securing organizational support and stimulating debate about proportionate mitigation activity, resource allocation, and shifts in current risk thinking.


Asunto(s)
Personal Administrativo , Monitoreo del Ambiente/legislación & jurisprudencia , Modelos Teóricos
2.
Sci Total Environ ; 755(Pt 1): 142868, 2021 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-33348485

RESUMEN

We explore the interplay between preventative risk management and regulatory style for the implementation of water safety plans in Malaysia and in England and Wales, two jurisdictions with distinct philosophies of approach. Semi-structured interviews were conducted with 32 water safety professionals in Malaysia, 23 in England and Wales, supported by 6 Focus Group Discussions (n = 53 participants). A grounded theory approach produced insights on the transition from drinking water quality surveillance to preventative risk management. Themes familiar to this type of regulatory transition emerged, including concerns about compliance policy; overseeing the risk management controls of regulatees with varied competencies and funds available to drive change; and the portfolio of interventions suited to a more facilitative regulatory style. Because the potential harm from waterborne illness is high where pathogen exposures occur, the transition to risk-informed regulation demands mature organisational cultures among water utilities and regulators, and a laser-like focus on ensuring risk management controls are delivered within water supply systems.

3.
Environ Syst Decis ; 41(4): 523-540, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34055567

RESUMEN

Risks and futures methods have complementary strengths as tools for managing strategic decisions under uncertainty. When combined, these tools increase organisational competency to evaluate and manage long-term risks, improving the flexibility and agility of the organisation to deal with gross uncertainties. Here, we set out a framework to guide the assessment of strategic risks for long-term business planning, based on its application at Portugal's largest water utility, Empresa Portuguesa das Águas Livres. Our approach extends strategic risk assessment by incorporating scenario planning-a futures approach used to help the utility move beyond single point forecast of risks to focus on critical dimensions of uncertainty that are fundamental to the resilience of corporate objectives and their vulnerability to external pressures. We demonstrate how we combine two complementary approaches-risk and futures-and use them to assess (i) how a set of baseline strategic risks for a water utility evolves under alternative futures, (ii) the aggregate corporate-level risk exposure, and (iii) the process and responses needed to manage multiple, interdependent strategic risks. The framework offers a corporate approach to evolving strategic risks and improves a utility's (i) knowledge of uncertainties, (ii) ability to assess the impacts of external developments over long time horizons and the consequences of actions and (iii) degree of flexibility to adapt to possible future challenges. The framework supports risk managers in their long-term strategic planning, through the appraisal and management of multiple, interdependent long-term strategic risks and can be replicated in other organisational contexts to bridge operational and corporate perspectives of enterprise risk.

4.
Sci Total Environ ; 646: 811-820, 2019 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-30064107

RESUMEN

This study re-analysed 14 semi-structured interviews with policy officials from the UK Department for Environment, Food and Rural Affairs (Defra) to explore the use of a variety of regulatory instruments and different levels of risk across 14 policy domains and 18 separately named risks. Interviews took place within a policy environment of a better regulation agenda and of broader regulatory reform. Of 619 (n) coded references to 5 categories of regulatory instrument, 'command and control' regulation (n = 257) and support mechanisms (n = 118) dominated the discussions, with a preference for 'command and control' cited in 8 of the policy domains. A framing analysis revealed officials' views on instrument effectiveness, including for sub-categories of the 5 key instruments. Views were mixed, though notably positive for economic instruments including taxation, fiscal instruments and information provision. An overlap analysis explored officials' mapping of public environmental risks to instrument types suited to their management. While officials frequently cite risk concepts generally within discussions, the extent of overlap for risks of specific significance was low across all risks. Only 'command and control' was mapped to risks of moderate significance in likelihood and impact severity. These results show that policy makers still prefer 'command and control' approaches when a certainty of outcome is sought and that alternative means are sought for lower risk situations. The detailed reasons for selection, including the mapping of certain instruments to specific risk characteristics, is still developing.


Asunto(s)
Política Ambiental , Contaminación Ambiental/legislación & jurisprudencia , Personal Administrativo , Formulación de Políticas , Factores de Riesgo
5.
Environ Int ; 127: 253-266, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30928849

RESUMEN

A circular economy relies on demonstrating the quality and environmental safety of wastes that are recovered and reused as products. Policy-level risk assessments, using generalised exposure scenarios, and informed by stakeholder communities have been used to appraise the acceptability of necessary changes to legislation, allowing wastes to be valued, reused and marketed. Through an extensive risk assessment exercise, summarised in this paper, we explore the burden of proof required to offer safety assurance to consumer and brand-sensitive food sectors in light of attempts to declassify, as wastes, quality-assured, source-segregated compost and anaerobic digestate products in the United Kingdom. We report the residual microbiological and chemical risks estimated for both products in land application scenarios and discuss these in the context of an emerging UK bioeconomy worth £52bn per annum. Using plausible worst case assumptions, as demanded by the quality food sector, risk estimates and hazard quotients were estimated to be low or negligible. For example, the human health risk of E. coli 0157 illness from exposure to microbial residuals in quality-assured composts, through a ready-to-eat vegetable consumption exposure route, was estimated at ~10-8 per person per annum. For anaerobic digestion residues, 7 × 10-3cases of E. coli 0157 were estimated per annum, a potential contribution of 0.0007% of total UK cases. Hazard quotients for potential chemical contaminants in both products were insufficient in magnitude to merit detailed quantitative risk assessments. Stakeholder engagement and expert review was also a substantive feature of this study. We conclude that quality-assured, source-segregated products applied to land, under UK quality protocols and waste processing standards, pose negligible risks to human, animal, environmental and crop receptors, providing that risk management controls set within the standards and protocols are adhered to.


Asunto(s)
Compostaje , Anaerobiosis , Animales , Compostaje/economía , Escherichia coli , Humanos , Medición de Riesgo , Suelo/química , Reino Unido
6.
Sci Total Environ ; 648: 25-32, 2019 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-30107303

RESUMEN

A novel dual excitation wavelength based bioaerosol sensor with multiple fluorescence bands called Spectral Intensity Bioaerosol Sensor (SIBS) has been assessed across five contrasting outdoor environments. The mean concentrations of total and fluorescent particles across the sites were highly variable being the highest at the agricultural farm (2.6 cm-3 and 0.48 cm-3, respectively) and the composting site (2.32 cm-3 and 0.46 cm-3, respectively) and the lowest at the dairy farm (1.03 cm-3 and 0.24 cm-3, respectively) and the sewage treatment works (1.03 cm-3 and 0.25 cm-3, respectively). In contrast, the number-weighted fluorescent fraction was lowest at the agricultural site (0.18) in comparison to the other sites indicating high variability in nature and magnitude of emissions from environmental sources. The fluorescence emissions data demonstrated that the spectra at different sites were multimodal with intensity differences largely at wavelengths located in secondary emission peaks for λex 280 and λex 370. This finding suggests differences in the molecular composition of emissions at these sites which can help to identify distinct fluorescence signature of different environmental sources. Overall this study demonstrated that SIBS provides additional spectral information compared to existing instruments and capability to resolve spectrally integrated signals from relevant biological fluorophores could improve selectivity and thus enhance discrimination and classification strategies for real-time characterisation of bioaerosols from environmental sources. However, detailed lab-based measurements in conjunction with real-world studies and improved numerical methods are required to optimise and validate these highly resolved spectral signatures with respect to the diverse atmospherically relevant biological fluorophores.

7.
Anal Chem ; 80(18): 7090-6, 2008 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-18700781

RESUMEN

A sequential ultrasonic extraction method for contaminated soils with weathered hydrocarbons is presented. The method covers the determination of total petroleum hydrocarbons between nC 8 and nC 40, and subranges of hydrocarbons including diesel range organic compounds, kerosene range organic compounds, and mineral oil range organic compounds in soils. Further modifications to the carbon banding may be made as requested for risk assessment. These include a series of ranges known as Texas banding (from the Texas Risk Reduction Program) as well as separation of the aliphatic and aromatic fractions. The method can be routinely used for measuring hydrocarbons down to 10 mg kg (-1) in soil. Lower limits can be achieved by employing a suitable solvent concentration step following extraction; however, this would result in increased cycle time. Detection limits may vary for individual carbon ranges calculated on the percentage of the full range they cover. With an extraction efficiency and recovery between >or=95 and 99%, this method can be easily positioned as a good alternative to Soxhlet extraction and shows a good potential for implementation as a standard method potentially providing further insight to the contaminated land sector.


Asunto(s)
Fraccionamiento Químico/métodos , Hidrocarburos/análisis , Hidrocarburos/aislamiento & purificación , Contaminantes del Suelo/análisis , Contaminantes del Suelo/aislamiento & purificación , Hidrocarburos Aromáticos/análisis , Hidrocarburos Aromáticos/aislamiento & purificación , Petróleo/análisis , Riesgo , Sensibilidad y Especificidad , Solventes/química , Ultrasonido , Reino Unido
8.
Environ Int ; 34(8): 1120-31, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18554718

RESUMEN

We present a model for benchmarking risk analysis and risk based decision making practice within organisations. It draws on behavioural and normative risk research, the principles of capability maturity modelling and our empirical observations. It codifies the processes of risk analysis and risk based decision making within a framework that distinguishes between different levels of maturity. Application of the model is detailed within the selected business functions of a water and wastewater utility. Observed risk analysis and risk based decision making practices are discussed, together with their maturity of implementation. The findings provide academics, utility professionals, and regulators a deeper understanding of the practical and theoretical underpinnings of risk management, and how distinctions can be made between organisational capabilities in this essential business process.


Asunto(s)
Benchmarking , Gestión de Riesgos/normas , Abastecimiento de Agua , Toma de Decisiones
9.
Chemosphere ; 71(8): 1432-9, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18267327

RESUMEN

Level I and II fugacity approaches were used to model the environmental distribution of benzene, anthracene, phenanthrene, 1-methylphenanthrene and benzo[a]pyrene in a four phase biopile system, accounting for air, water, mineral soil and non-aqueous phase liquid (oil) phase. The non-aqueous phase liquid (NAPL) and soil phases were the dominant partition media for the contaminants in each biopile and the contaminants differed markedly in their individual fugacities. Comparison of three soils with different percentage of organic carbon (% org C) showed that the % org C influenced contaminant partitioning behaviour. While benzene showed an aqueous concentration worthy of note for leachate control during biopiling, other organic chemicals showed that insignificant amount of chemicals leached into the water, greatly reducing the potential extent of groundwater contamination. Level II fugacity model showed that degradation was the dominant removal process except for benzene. In all three biopile systems, the rate of degradation of benzo(a)pyrene was low, requiring more than 12 years for soil concentrations from a spill of about 25 kg (100 mol) to be reduced to a concentration of 0.001 microgg(-1). The removal time of 1-methylphenanthrene and either anthracene or phenanthrene was about 1 and 3 years, respectively. In contrast, benzene showed the highest degradation rate and was removed after 136 days in all biopile systems. Overall, this study confirms the association of risk critical contaminants with the residual saturation in treated soils and reinforces the importance of accounting for the partitioning behaviour of both NAPL and soil phases during the risk assessment of oil-contaminated sites.


Asunto(s)
Aceites/química , Contaminantes del Suelo/análisis , Suelo/análisis , Antracenos/análisis , Antracenos/química , Benceno/análisis , Benceno/química , Benzo(a)pireno/análisis , Benzo(a)pireno/química , Modelos Teóricos , Fenantrenos/análisis , Fenantrenos/química , Contaminantes del Suelo/química
10.
Chemosphere ; 73(4): 551-6, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18657288

RESUMEN

This paper presents a method for the determination of alkylphenols, alkylphenol polyethoxylates (APEO) and alkylphenol ethoxycarboxylates (APEC) in the aqueous and particulate phase of wastewater samples. Quantification was achieved by liquid chromatography-tandem mass spectrometry. The sensitivity of the method is demonstrated by low detection limits, in the dissolved phase 1.2-9.6ngl(-1) for alkylphenol, AP1-3EO and APEC and 0.1-4.1ngl(-1) for longer chain alkylphenol polyethoxylates. The method detection limit for particulate phase samples ranged from 6 to 60ngg(-1) for AP, AP1-3EO and APEC; with the longer chain APEO being from 0.5 to 20ngg(-1). Matrix effects were noted in complex matrix rich samples. There was a distinct change in the distribution of alkylphenol ethoxylates during biological treatment of the wastewater, with the major biotransformation products observed being carboxylated derivatives at concentrations of up to 1768ngl(-1). Shorter chain APEO were present in higher proportions in the suspended solids, due to their higher affinity to particulate matter compared to the long-chain oligomers.


Asunto(s)
Ácidos Carboxílicos/análisis , Fenoles/análisis , Aguas del Alcantarillado/análisis , Contaminantes Químicos del Agua/análisis , Ácidos Carboxílicos/química , Cromatografía Liquida , Filtración , Fenoles/química , Reproducibilidad de los Resultados , Aguas del Alcantarillado/química , Espectrometría de Masas en Tándem , Contaminantes Químicos del Agua/química
11.
Sci Total Environ ; 618: 1486-1496, 2018 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-29103652

RESUMEN

We report dynamic changes in the priorities for strategic risks faced by international water utilities over a 10year period, as cited by managers responsible for managing them. A content analysis of interviews with three cohorts of risk managers in the water sector was undertaken. Interviews probed the focus risk managers' were giving to strategic risks within utilities, as well as specific questions on risk analysis tools (2005); risk management cultures (2011) and the integration of risk management with corporate decision-making (2015). The coding frequency of strategic (business, enterprise, corporate) risk terms from 18 structured interviews (2005) and 28 semi-structured interviews (12 in 2011; 16 in 2015) was used to appraise changes in the perceived importance of strategic risks within the sector. The aggregated coding frequency across the study period, and changes in the frequency of strategic risks cited at three interview periods identified infrastructure assets as the most significant risk over the period and suggests an emergence of extrinsic risk over time. Extended interviews with three utility risk managers (2016) from the UK, Canada and the US were then used to contextualise the findings. This research supports the ongoing focus on infrastructure resilience and the increasing prevalence of extrinsic risk within the water sector, as reported by the insurance sector and by water research organisations. The extended interviews provided insight into how strategic risks are now driving the implementation agenda within utilities, and into how utilities can secure tangible business value from proactive risk governance. Strategic external risks affecting the sector are on the rise, involve more players and are less controllable from within a utility's own organisational boundaries. Proportionate risk management processes and structures provide oversight and assurance, whilst allowing a focus on the tangible business value that comes from managing strategic risks well.

12.
Sci Total Environ ; 576: 895-906, 2017 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-27842293

RESUMEN

We investigated cultural influences on the implementation of water safety plans (WSPs) using case studies from WSP pilots in India, Uganda and Jamaica. A comprehensive thematic analysis of semi-structured interviews (n=150 utility customers, n=32 WSP 'implementers' and n=9 WSP 'promoters'), field observations and related documents revealed 12 cultural themes, offered as 'enabling', 'limiting', or 'neutral', that influence WSP implementation in urban water utilities to varying extents. Aspects such as a 'deliver first, safety later' mind set; supply system knowledge management and storage practices; and non-compliance are deemed influential. Emergent themes of cultural influence (ET1 to ET12) are discussed by reference to the risk management, development studies and institutional culture literatures; by reference to their positive, negative or neutral influence on WSP implementation. The results have implications for the utility endorsement of WSPs, for the impact of organisational cultures on WSP implementation; for the scale-up of pilot studies; and they support repeated calls from practitioner communities for cultural attentiveness during WSP design. Findings on organisational cultures mirror those from utilities in higher income nations implementing WSPs - leadership, advocacy among promoters and customers (not just implementers) and purposeful knowledge management are critical to WSP success.


Asunto(s)
Agua Potable/normas , Gestión de Riesgos , Abastecimiento de Agua/normas , India , Jamaica , Uganda
13.
Environ Pollut ; 225: 390-402, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28283411

RESUMEN

A means for identifying and prioritising the treatment of uncertainty (UnISERA) in environmental risk assessments (ERAs) is tested, using three risk domains where ERA is an established requirement and one in which ERA practice is emerging. UnISERA's development draws on 19 expert elicitations across genetically modified higher plants, particulate matter, and agricultural pesticide release and is stress tested here for engineered nanomaterials (ENM). We are concerned with the severity of uncertainty; its nature; and its location across four accepted stages of ERAs. Using an established uncertainty scale, the risk characterisation stage of ERA harbours the highest severity level of uncertainty, associated with estimating, aggregating and evaluating expressions of risk. Combined epistemic and aleatory uncertainty is the dominant nature of uncertainty. The dominant location of uncertainty is associated with data in problem formulation, exposure assessment and effects assessment. Testing UnISERA produced agreements of 55%, 90%, and 80% for the severity level, nature and location dimensions of uncertainty between the combined case studies and the ENM stress test. UnISERA enables environmental risk analysts to prioritise risk assessment phases, groups of tasks, or individual ERA tasks and it can direct them towards established methods for uncertainty treatment.


Asunto(s)
Exposición a Riesgos Ambientales/estadística & datos numéricos , Monitoreo del Ambiente/normas , Agricultura , Ambiente , Humanos , Plaguicidas , Proyectos de Investigación , Medición de Riesgo/métodos , Incertidumbre
14.
Sci Total Environ ; 595: 537-546, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-28395269

RESUMEN

Strategic risk appraisal (SRA) has been applied to compare diverse policy level risks to and from the environment in England and Wales. Its application has relied on expert-informed assessments of the potential consequences from residual risks that attract policy attention at the national scale. Here we compare consequence assessments, across environmental, economic and social impact categories that draw on 'expert'- and 'literature-based' analyses of the evidence for 12 public risks appraised by Government. For environmental consequences there is reasonable agreement between the two sources of assessment, with expert-informed assessments providing a narrower dispersion of impact severity and with median values similar in scale to those produced by an analysis of the literature. The situation is more complex for economic consequences, with a greater spread in the median values, less consistency between the two assessment types and a shift toward higher severity values across the risk portfolio. For social consequences, the spread of severity values is greater still, with no consistent trend between the severities of impact expressed by the two types of assessment. For the latter, the findings suggest the need for a fuller representation of socioeconomic expertise in SRA and the workshops that inform SRA output.

15.
Int J Hyg Environ Health ; 220(1): 17-28, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27745825

RESUMEN

Bioaerosols are released in elevated quantities from composting facilities and are associated with negative health effects, although dose-response relationships are unclear. Exposure levels are difficult to quantify as established sampling methods are costly, time-consuming and current data provide limited temporal and spatial information. Confidence in dispersion model outputs in this context would be advantageous to provide a more detailed exposure assessment. We present the calibration and validation of a recognised atmospheric dispersion model (ADMS) for bioaerosol exposure assessments. The model was calibrated by a trial and error optimisation of observed Aspergillus fumigatus concentrations at different locations around a composting site. Validation was performed using a second dataset of measured concentrations for a different site. The best fit between modelled and measured data was achieved when emissions were represented as a single area source, with a temperature of 29°C. Predicted bioaerosol concentrations were within an order of magnitude of measured values (1000-10,000CFU/m3) at the validation site, once minor adjustments were made to reflect local differences between the sites (r2>0.7 at 150, 300, 500 and 600m downwind of source). Results suggest that calibrated dispersion modelling can be applied to make reasonable predictions of bioaerosol exposures at multiple sites and may be used to inform site regulation and operational management.


Asunto(s)
Contaminantes Atmosféricos/análisis , Aspergillus fumigatus , Modelos Teóricos , Suelo , Aerosoles , Microbiología del Aire , Movimientos del Aire , Calibración , Monitoreo del Ambiente , Humanos , Reproducibilidad de los Resultados
16.
Environ Int ; 32(8): 958-66, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16870255

RESUMEN

Over the last decade, suppliers of drinking water have recognised the limitations of relying solely on end-product monitoring to ensure safe water quality and have sought to reinforce their approach by adopting preventative strategies where risks are proactively identified, assessed and managed. This is leading to the development of water safety plans; structured 'route maps' for managing risks to water supply, from catchment to consumer taps. This paper reviews the Hazard Analysis and Critical Control Point (HACCP) procedure on which many water safety plans are based and considers its appropriateness in the context of drinking water risk management. We examine water safety plans in a broad context, looking at a variety of monitoring, optimisation and risk management initiatives that can be taken to improve drinking water safety. These are cross-compared using a simple framework that facilitates an integrated approach to water safety. Finally, we look at how risk management practices are being integrated across water companies and how this is likely to affect the future development of water safety plans.


Asunto(s)
Monitoreo del Ambiente/métodos , Sustancias Peligrosas/análisis , Control de Calidad , Gestión de Riesgos/métodos , Gestión de la Calidad Total/métodos , Abastecimiento de Agua/normas , Animales , Monitoreo del Ambiente/normas , Enfermedades Transmitidas por los Alimentos/prevención & control , Salud Global , Política de Salud , Humanos , Gestión de Riesgos/normas , Gestión de la Calidad Total/normas , Contaminación del Agua/prevención & control
17.
Environ Int ; 32(8): 948-57, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16839605

RESUMEN

Millions of people die every year around the world from diarrheal diseases much of which is caused by contaminated drinking water. By contrast, drinking water safety is largely taken for granted by many citizens of affluent nations. The ability to drink water that is delivered into households without fear of becoming ill may be one of the key defining characteristics of developed nations in relation to the majority of the world. Yet there is well-documented evidence that disease outbreaks remain a risk that could be better managed and prevented even in affluent nations. A detailed retrospective analysis of more than 70 case studies of disease outbreaks in 15 affluent nations over the past 30 years provides the basis for much of our discussion [Hrudey, S.E. and Hrudey, E.J. Safe Drinking Water--Lessons from Recent Outbreaks in Affluent Nations. London, UK: IWA Publishing; 2004.]. The insights provided can assist in developing a better understanding within the water industry of the causes of drinking water disease outbreaks, so that more effective preventive measures can be adopted by water systems that are vulnerable. This preventive feature lies at the core of risk management for the provision of safe drinking water.


Asunto(s)
Gestión de Riesgos/métodos , Gestión de la Calidad Total/métodos , Microbiología del Agua , Purificación del Agua/métodos , Abastecimiento de Agua/normas , Animales , Brotes de Enfermedades , Salud Global , Política de Salud , Humanos , Medición de Riesgo
18.
Environ Pollut ; 143(3): 489-98, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16448732

RESUMEN

A preliminary evaluation of compound-specific isotope analysis (CSIA) as a novel, alternative method for identifying source correlation compounds in soils contaminated with residual heavy or weathered petroleum wastes is presented. Oil-contaminated soil microcosms were established using soil (sandy-loam, non-carbonaceous cley) amended with ballast-, crude- or No.6 fuel oil. Microcosms were periodically sampled over 256 days and delta(13)C values (which express the ratio of (13)C to (12)C) determined at each time point for five n-alkanes and the isoprenoid norpristane using gas chromatography-isotope ratio mass spectrometry (GC-IRMS). Although some temporal variation was observed, no significant temporal shifts in the delta(13)C values for the five n-alkanes were measured in all three oils. Isoprenoid isotope ratios (delta(13)C) appeared to be least affected by biotransformation, especially in the No.6 fuel oil. The research suggests that the delta(13)C of isoprenoids such as norpristane, may be of use as source correlation parameters.


Asunto(s)
Isótopos de Carbono/química , Residuos Industriales , Petróleo/análisis , Contaminantes del Suelo/química , Biodegradación Ambiental , Ecosistema , Monitoreo del Ambiente/métodos , Humanos , Espectrometría de Masas/métodos
19.
Environ Pollut ; 144(3): 1013-23, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16603294

RESUMEN

A fugacity approach was evaluated to reconcile loadings of vinyl chloride (chloroethene), benzene, 1,3-butadiene and trichloroethylene in waste with concentrations observed in landfill gas monitoring studies. An evaluative environment derived from fictitious but realistic properties such as volume, composition, and temperature, constructed with data from the Brogborough landfill (UK) test cells was used to test a fugacity approach to generating the source term for use in landfill gas risk assessment models (e.g. GasSim). SOILVE, a dynamic Level II model adapted here for landfills, showed greatest utility for benzene and 1,3-butadiene, modelled under anaerobic conditions over a 10 year simulation. Modelled concentrations of these components (95,300 microg m(-3); 43 microg m(-3)) fell within measured ranges observed in gas from landfills (24,300-180,000 microg m(-3); 20-70 microg m(-3)). This study highlights the need (i) for representative and time-referenced biotransformation data; (ii) to evaluate the partitioning characteristics of organic matter within waste systems and (iii) for a better understanding of the role that gas extraction rate (flux) plays in producing trace component concentrations in landfill gas.


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Gases/análisis , Modelos Estadísticos , Eliminación de Residuos , Benceno/análisis , Biodegradación Ambiental , Butadienos/análisis , Fenómenos Geológicos , Geología , Metano/análisis , Medición de Riesgo/métodos , Tricloroetileno/análisis , Cloruro de Vinilo/análisis , Volatilización , Viento
20.
Sci Total Environ ; 572: 23-33, 2016 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-27490300

RESUMEN

A reliable characterisation of uncertainties can aid uncertainty identification during environmental risk assessments (ERAs). However, typologies can be implemented inconsistently, causing uncertainties to go unidentified. We present an approach based on nine structured elicitations, in which subject-matter experts, for pesticide risks to surface water organisms, validate and assess three dimensions of uncertainty: its level (the severity of uncertainty, ranging from determinism to ignorance); nature (whether the uncertainty is epistemic or aleatory); and location (the data source or area in which the uncertainty arises). Risk characterisation contains the highest median levels of uncertainty, associated with estimating, aggregating and evaluating the magnitude of risks. Regarding the locations in which uncertainty is manifest, data uncertainty is dominant in problem formulation, exposure assessment and effects assessment. The comprehensive description of uncertainty described will enable risk analysts to prioritise the required phases, groups of tasks, or individual tasks within a risk analysis according to the highest levels of uncertainty, the potential for uncertainty to be reduced or quantified, or the types of location-based uncertainty, thus aiding uncertainty prioritisation during environmental risk assessments. In turn, it is expected to inform investment in uncertainty reduction or targeted risk management action.


Asunto(s)
Organismos Acuáticos/efectos de los fármacos , Testimonio de Experto , Plaguicidas/efectos adversos , Medición de Riesgo/métodos , Agua Dulce
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