共查询到20条相似文献,搜索用时 15 毫秒
1.
Linda J. Young Carol A. Gotway 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(5):589-600
A nationwide Environmental Public Health Tracking program is being created to monitor environmental impacts on human health.
This, and many other efforts to relate environmental and health outcomes, depend largely on the synthesis of existing data
sets; little new data are being generated for this purpose. More often than not, the data available for such synthesis have
been collected for different geographic or spatial units, and any set of these units may be different from the one of interest.
In this paper, we compare and contrast two approaches that can be used within a Geographic Information System to link spatial
data from different sources. The first approach works with centroids of areal units and is commonly used in environmental
health analyses. The second approach honors the spatial support (size, shape and orientation) of the data. Using traditional
regression models and a spatially-varying coefficient regression model, we show that different linkage methods can lead to
different inference. We describe key ideas pertaining to the support of spatial data that are often ignored in many analyses
of environmental health data and present a general analytical approach to change-of-support problems. 相似文献
2.
Lawrence D. Lemke Andrew S. Bahrou 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(1):27-39
Quantifying human cancer risk arising from exposure to contaminated groundwater is complicated by the many hydrogeological,
environmental, and toxicological uncertainties involved. In this study, we used Monte Carlo simulation to estimate cancer
risk associated with tetrachloroethene (PCE) dissolved in groundwater by linking three separate models for: (1) reactive contaminant
transport; (2) human exposure pathways; and (3) the PCE cancer potency factor. The hydrogeologic model incorporates an analytical
solution for a one-dimensional advective–dispersive–reactive transport equation to determine the PCE concentration in a water
supply well located at a fixed distance from a continuous source. The pathway model incorporates PCE exposure through ingestion,
inhalation, and dermal contact. The toxicological model combines epidemiological data from eight rodent bioassays of PCE exposure
in the form of a composite cumulative distribution frequency curve for the human PCE cancer potency factor. We assessed the
relative importance of individual model variables through their correlation with expected cancer risk calculated in an ensemble
of Monte Carlo simulations with 20,000 trials. For the scenarios evaluated, three factors were most highly correlated with
cancer risk: (1) the microbiological decay constant for PCE in groundwater, (2) the linear groundwater pore velocity, and
(3) the cancer potency factor. We then extended our analysis beyond conventional expected value risk assessment using the
partitioned multiobjective risk method (PMRM) to generate expected-value functions conditional to a 1 in 100,000 increased
cancer risk threshold. This approach accounts for low probability/high impact outcomes separately from the conventional unconditional
expected values. Thus, information on potential worst-case outcomes can be quantified for decision makers. Using PMRM, we
evaluated the cost-benefit relationship of implementing several postulated risk management alternatives intended to mitigate
the expected and conditional cancer risk. Our results emphasize the importance of hydrogeologic models in risk assessment,
but also illustrate the importance of integrating environmental and toxicological uncertainty. When coupled with the PMRM,
models integrating uncertainty in transport, exposure, and potency constitute an effective risk assessment tool for use within
a risk-based corrective action (RBCA) framework. 相似文献
3.
For earthquake disaster mitigation,we use historical records and more complete intensity investigation data from 1500 to 2015 to analyze and estimate the seismic intensity and frequency of the earthquake-prone areas in Yunnan. We digitized intensity observations and divided the Yunnan region into cell size of 0. 2°× 0. 2° to calculate the seismic intensity-frequency relationship for each cell. Combined with a repeated cycle of intensity of one hundred years and population economics data in Yunnan,we analyze future areas of concern. The results can provide a reference for earthquake hazardous area zoning.This method is based on historical earthquake data,reducing as much as possible the various hypotheses for the assessment,and thus can concisely reflect the different intensityfrequency distributions of the region. 相似文献
4.
Sakurajima volcano: a physico-chemical study of the health consequences of long-term exposure to volcanic ash 总被引:1,自引:1,他引:0
S. E. Hillman C. J. Horwell A. L. Densmore D. E. Damby B. Fubini Y. Ishimine M. Tomatis 《Bulletin of Volcanology》2012,74(4):913-930
Regular eruptions from Sakurajima volcano, Japan, repeatedly cover local urban areas with volcanic ash. The frequency of exposure
of local populations to the ash led to substantial concerns about possible respiratory health hazards, resulting in many epidemiological
and toxicological studies being carried out in the 1980s. However, very few mineralogical data were available for determination
of whether the ash was sufficiently fine to present a respiratory hazard. In this study, we review the existing studies and
carry out mineralogical, geochemical and toxicological analyses to address whether the ash from Sakurajima has the potential
to cause respiratory health problems. The results show that the amount of respirable (<4 μm) material produced by the volcano
is highly variable in different eruptions (1.1–18.8 vol.%). The finest samples derive from historical, plinian eruptions but
considerable amounts of respirable material were also produced from the most recent vulcanian eruptive phase (since 1955).
The amount of cristobalite, a crystalline silica polymorph which has the potential to cause chronic respiratory diseases,
is ~3–5 wt.% in the bulk ash. Scanning electron microscope and transmission electron microscope imaging showed no fibrous
particles similar to asbestos particles. Surface reactivity tests showed that the ash did not produce significant amounts
of highly reactive hydroxyl radicals (0.09–1.35 μmol m−2 at 30 min.) in comparison to other volcanic ash types. A basic toxicology assay to assess the ability of ash to rupture the
membrane of red blood cells showed low propensity for haemolysis. The findings suggest that the potential health hazard of
the ash is low, but exposure and respiratory conditions should still be monitored given the high frequency and durations of
exposure. 相似文献
5.
Associations between outdoor air quality and birth weight: a geostatistical sequential simulation approach in Coastal Alentejo,Portugal 总被引:3,自引:2,他引:1
Manuel Castro Ribeiro Pedro Pinho Esteve Llop Cristina Branquinho Amílcar Soares Maria João Pereira 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(3):527-540
Several environmental health studies suggest birth weight is associated with outdoor air pollution during gestation. In these studies, exposure assignments are usually based on measurements collected at air quality monitoring stations that do not coincide with health data locations. So, estimated exposures can be misleading if they do not take into account the uncertainty of exposure estimates. In this article we conducted a semi-ecological study to analyze associations between air quality during gestation and birth weight. Air quality during gestation was measured using a biomonitor, as an alternative to traditional air quality monitoring stations data, in order to increase spatial resolution of exposure measurements. To our knowledge this is the first time that the association between air quality and birth weight is studied using biomonitors. To address exposure uncertainty at health locations, we applied geostatistical simulation on biomonitoring data that provided multiple equally probable realizations of biomonitoring data, with reproduction of observed histogram and spatial covariance while matching for conditioning data. Each simulation represented a measure of exposure at each location. The set of simulations provided a measure of exposure uncertainty at each location. To incorporate uncertainty in our analysis we used generalized linear models, fitted simulation outputs and health data on birth weights and assessed statistical significance of exposure parameter using non-parametric bootstrap techniques. We found a positive association between air quality and birth weight. However, this association was not statistically significant. We also found a modest but significant association between air quality and birth weight among babies exposed to gestational tobacco smoke. 相似文献
6.
Recently emerged indications imply that particular concentrations and qualities of dissolved organic carbon (DOC) have the potential to reduce species diversity in zooplankton. In this contribution, we tested the impact of a major component of DOC, the dissolved humic substances (HSs), on two life history traits of a clone of Daphnia magna, namely lifespan and reproduction. We chose reproduction as a variable since it guarantees the persistence of the population in its habitat, and lifespan was selected as the most integrative individual variable. We found that lifespan was extended by exposure to HSs, but lifetime reproduction was clearly reduced. On the other hand, the mineral and biochemical composition of food also significantly modulated these life history traits. By feeding coccal green algae that contained linolenic acid, arginine (Arg), and histidine (His), but that lacked polyunsaturated fatty acids (PUFAs) with C-back bones >18, we examined how short-chained PUFAs, either alone or in concert with Arg and His, are able to modulate life history traits. Our expectation was that the additional challenge by HSs would shift the energy allocation in favor of reproduction. We found that the carbon and amino acid content may account for longevity, even when challenged by HSs. Reproduction appeared to be triggered by the C:P and N:P ratios of the food, particularly given the rather low P-content, which was within the range of severe growth limitation. Consequently, exposure to HSs reduced offspring numbers. Resting eggs without males occurred only in Desmodesmus armatus fed Daphnia that were simultaneously exposed to HSs. Under these conditions, the total amino acid (AA) content seemed to trigger reproduction. In summary, exposure to HSs appeared to have the potential to change the competitive ability of zooplankters by modulating the energy allocation between body maintenance and reproduction. 相似文献
7.
8.
With the Water Framework Directive (WFD) the European Commission (EC) is requested to define environmental quality standards for pollutants to protect aquatic life in surface waters. Quality standards have to be derived by a scientific risk assessment and should not be exceeded. The recommended quality standards are mainly based on long term toxicological tests with algae, crustaceans and fish. The lowest effect concentration is divided by an assessment factor between 10 and 1000, which considers the data quality and quantity. In this work funded by the German Länder Working Party on Water (Länderarbeitsgemeinschaft Wasser – LAWA) environmental quality standards for 40 considered relevant substances were derived for aquatic ecosystems. The data sheets cover the identification of the compounds, their behaviour in the environment (physical‐chemical properties, biotic and abiotic degradation, sorption, bioaccumulation), information about mode of action, uses, analytical determination and available quality criteria. Ecotoxicological effect concentrations for bacteria, algae, protozoa, aquatic plants, crustaceans, fish, amphibians, insects and molluscs are listed. For 17 of the 40 hazardous substances investigated, quality objectives above 1 μg/L were derived. For 12 substances the values were between 0.1 μg/L and 1 μg/L and for 5 substances lower than 0.1 μg/L. Incomplete ecotoxicological data sets of the remaining compounds do not allow the derivation of quality standards. Especially for drugs further ecotoxicological test results are needed. 相似文献
9.
W. Douglas Thompson Daniel Wartenberg 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(5):635-646
Much research in environmental epidemiology relies on aggregate-level information on exposure to potentially toxic substances
and on relevant covariates. We compare the use of additive (linear) and multiplicative (log-linear) regression models for
the analysis of such data. We illustrate how both additive and multiplicative models can be fit to aggregate-level data sets
in which disease incidence is the dependent variable, and contrast these results with similar models fitted to individual-level
data. We find (1) that for aggregate-level data, multiplicative models are more likely than additive models to introduce bias
into the estimation of rates, an effect not found with individual-level data; and (2) that under many circumstances multiplicative
models reduce the precision of the estimates, an effect also not found in individual-level models. For both additive and multiplicative
models of aggregate-level data, we find that, in the presence of covariates, narrow confidence interval are obtained only
when two or more antecedent factors are strongly related to the measured covariate and/or the exposure of primary substantive
interest. We conclude that the equivalency of fitting additive versus multiplicative models in studies with individual-level
binary data does not carry over to studies that analyze aggregate-level information. For aggregate data, we strongly recommend
use of additive models.
Supported by Grant #1 U19 EH000102 from the National Center for Environmental Health, Centers for Disease Control and Prevention,
Atlanta, GA. 相似文献
10.
Quality Requirements for Fresh Waters: Water Quality Targets, Water Quality Objectives, and Chemical Water Quality Classification In the Federal Republic of Germany, water quality requirements for the protection of inland surface waters against hazardous substances are formulated on the basis of a quality targets derivation concept developed jointly by the Federal Government and the Federal States. The quality requirements were termed “water quality targets” in order to make it clear that the values derived are orientational values rather than legally binding limit values. The international comparison of quality requirements for surface waters shows that, on the whole, the national quality targets ensure a high level of protection. According to present scientific knowledge, impairments of uses, such as supply of drinking water, or risks to aquatic communities need not to be expected if the quality targets are complied with. A comparison of water quality data with the water quality targets makes it possible, on the one hand, to identify those substances whose inputs must be further reduced; on the other hand, it also shows that, for a number of substances, there is no need at present for concern over their adversely water quality. A further differentiation of the aquatic hazard potential of pollutants allows a water quality classification system to be developed on the basis of the quality targets derivation concept. The basic elements of this water quality classification system are presented, and its application is explained by way of examples. 相似文献
11.
Application of a stochastic model to estimate children’s short-term residential exposure to lead 总被引:1,自引:0,他引:1
Robert A. Canales James O. Leckie 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(6):737-745
The Cumulative and Aggregate Simulation of Exposure (CASE) framework is an innovative simulation tool for exploring non-dietary
exposures to environmental contaminants. Built upon the Dermal Exposure Reduction Model (DERM) and established methods for
collecting detailed human activity patterns, the CASE framework improves upon its predecessor. Although prompted in part by
the Food Quality Protection Act of 1996 and the need to assess aggregate exposure to pesticides, the framework was designed
to be flexible enough to assess exposure to other contaminants. This paper examines features of the CASE framework in an illustrative
application estimating children’s dermal and non-dietary ingestion exposure to lead in the residential environment. Concentration
values in various media are taken from a nationwide study and exposure factors are obtained from the literature. Activity
pattern input includes sequential micro-level activities collected for 20 children (ages 1 through 6). Modeled results are
explored via classification trees and sensitivity analysis. Results of each exposure route are also compared to independent
data. Median dermal exposure estimates were 589 and 558 μg/m3 for the right and left hands, respectively, with the resulting output most sensitive to exposure factor terms. The simulation
estimated a median non-dietary ingestion rate of 9.5 μg of lead per day with estimates most sensitive to the surface area
of mouthed objects. 相似文献
12.
Applying Bayesian belief networks to health risk assessment 总被引:1,自引:0,他引:1
Kevin Fong-Rey Liu Che-Fan Lu Cheng-Wu Chen Yung-Shuen Shen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(3):451-465
The health risk of noncarcinogenic substances is usually represented by the hazard quotient (HQ) or target organ-specific
hazard index (TOSHI). However, three problems arise from these indicators. Firstly, the HQ overestimates the health risk of
noncarcinogenic substances for non-critical organs. Secondly, the TOSHI makes inappropriately the additive assumption for
multiple hazardous substances affecting the same organ. Thirdly, uncertainty of the TOSHI undermines the accuracy of risk
characterization. To address these issues, this article proposes the use of Bayesian belief networks (BBN) for health risk
assessment (HRA) and the procedure involved is developed using the example of road constructions. According to epidemiological
studies and using actual hospital attendance records, the BBN-HRA can specifically identify the probabilistic relationship
between an air pollutant and each of its induced disease, which can overcome the overestimation of the HQ for non-critical
organs. A fusion technique of conditional probabilities in the BBN-HRA is devised to avoid the unrealistic additive assumption.
The use of the BBN-HRA is easy even for those without HRA knowledge. The input of pollution concentrations into the model
will bring more concrete information on the morbidity and mortality rates of all the related diseases rather than a single
score, which can reduce the uncertainty of the TOSHI. 相似文献
13.
The prediction of PM2.5 concentrations with high spatiotemporal resolution has been suggested as a potential method for data collection to assess the health effects of exposure. This work predicted the weekly average PM2.5 concentrations in the Yangtze River Delta, China, by using a spatio-temporal model. Integrating land use data, including the areas of cultivated land, construction land, and forest land, and meteorological data, including precipitation, air pressure, relative humidity, temperature, and wind speed, we used the model to estimate the weekly average PM2.5 concentrations. We validated the estimated effects by using the cross-validated R2 and Root mean square error (RMSE); the results showed that the model performed well in capturing the spatiotemporal variability of PM2.5 concentration, with a reasonably large R2 of 0.86 and a small RMSE of 8.15 (μg/m3). In addition, the predicted values covered 94% of the observed data at the 95% confidence interval. This work provided a dataset of PM2.5 concentration predictions with a spatiotemporal resolution of 3 km × week, which would contribute to accurately assessing the potential health effects of air pollution. 相似文献
14.
Jennifer S. Le Blond Claire J. Horwell Peter J. Baxter Sabina A. K. Michnowicz Maura Tomatis Bice Fubini Pierre Delmelle Christina Dunster Herman Patia 《Bulletin of Volcanology》2010,72(9):1077-1092
The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007–08, raised concerns
regarding how exposure would affect the respiratory health of nearby populations and impact on the environment. As part of
a formal evaluation of the effects of volcanic emissions on public health, we investigated the potential health hazard of
the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy-andesitic ash comprised 2.1–6.7 vol.% respirable (sub-4 μm diameter) particles. The crystalline silica content was 1.9–5.0 wt.% cristobalite (in the bulk sample) with trace amounts
of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre-like particles (∼3–60 μm max. diameter) observed in some samples, which we confirmed to be CaSO4 (gypsum, at <6 wt.% in the bulk samples) and not asbestiform fibres. The ash specific surface area was low (0.1–2.7 m2 g−1). The leached solution from one of the ash samples was slightly acidic (pH 5.6), but did not contain high levels of toxic
metals (such as F, Cu, Zn, Mn, As, Ni and Cd) when compared to previously tested volcanic ash leachates. Ash samples generated
potentially-harmful hydroxyl radicals through an iron-mediated catalytic reaction, in the range of 0.15–2.47 μmol m−2 (after 30 min of reaction). However, measurement of particle oxidative capacity (potential oxidative stress reaction using
ascorbic acid) and silica-like injury to red blood cells (erythrolysis assay, i.e. measurement of cell death) nevertheless revealed low biological reactivity.
The findings suggest that acute exposure to the ash would have a limited potential to exacerbate pre-existing conditions such as asthma or chronic bronchitis, and the potential for chronic exposure leading to silicosis was
low. 相似文献
15.
Trevor I. Allen David J. Wald Paul S. Earle Kristin D. Marano Alicia J. Hotovec Kuowan Lin Michael G. Hearne 《Bulletin of Earthquake Engineering》2009,7(3):701-718
We present an Atlas of ShakeMaps and a catalog of human population exposures to moderate-to-strong ground shaking (EXPO-CAT)
for recent historical earthquakes (1973–2007). The common purpose of the Atlas and exposure catalog is to calibrate earthquake
loss models to be used in the US Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER). The full
ShakeMap Atlas currently comprises over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these
maps constrained—to varying degrees—by instrumental ground motions, macroseismic intensity data, community internet intensity
observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies.
Exposure to discrete levels of shaking intensity is obtained by correlating Atlas ShakeMaps with a global population database.
Combining this population exposure dataset with historical earthquake loss data, such as PAGER-CAT, provides a useful resource
for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. We illustrate two example
uses for EXPO-CAT; (1) simple objective ranking of country vulnerability to earthquakes, and; (2) the influence of time-of-day
on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices
tend to cluster spatially in terms of relative vulnerability. We also find little quantitative evidence to suggest that time-of-day
is a significant factor in earthquake mortality. Moreover, earthquake mortality appears to be more systematically linked to
the population exposed to severe ground shaking (Modified Mercalli Intensity VIII+). Finally, equipped with the full Atlas
of ShakeMaps, we merge each of these maps and find the maximum estimated peak ground acceleration at any grid point in the
world for the past 35 years. We subsequently compare this “composite ShakeMap” with existing global hazard models, calculating
the spatial area of the existing hazard maps exceeded by the combined ShakeMap ground motions. In general, these analyses
suggest that existing global, and regional, hazard maps tend to overestimate hazard. Both the Atlas of ShakeMaps and EXPO-CAT
have many potential uses for examining earthquake risk and epidemiology. All of the datasets discussed herein are available
for download on the PAGER Web page ().
T. I. Allen and M. G. Hearne—contracted through Synergetics Incorporated. 相似文献
16.
An application of Spartan spatial random fields in environmental mapping: focus on automatic mapping capabilities 总被引:4,自引:2,他引:2
Samuel N. Elogne Dionissios T. Hristopulos Emmanouil Varouchakis 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(5):633-646
This paper investigates the potential of Spartan spatial random fields (SSRFs) in real-time mapping applications. The data
set that we study focuses on the distribution of daily gamma dose rates over part of Germany. Our goal is to determine a Spartan
spatial model from the data, and then use it to generate “predictive” maps of the radioactivity. In the SSRF framework, the
spatial dependence is determined from sample functions that focus on short-range correlations. A recently formulated SSRF
predictor is used to derive isolevel contour maps of the dose rates. The SSRF predictor is explicit. Moreover, the adjustments that it requires by the user are reduced compared to classical geostatistical methods. These features
present clear advantages for an automatic mapping system. The performance of the SSRF predictor is evaluated by means of various
cross-validation measures. The values of the performance measures are similar to those obtained by classical geostatistical
methods. Application of the SSRF method to data that simulate a radioactivity release scenario is also discussed. Hot spots
are detected and removed using a heuristic method. The extreme values that appear in the path of the simulated plume are not
captured by the currently used Spartan spatial model. Modeling of the processes leading to extreme values can enhance the
predictive capabilities of the spatial model, by incorporating physical information. 相似文献
17.
Effect of a single vibrating building on free-field ground motion: numerical and experimental evidences 总被引:1,自引:1,他引:0
R. Ditommaso M. Mucciarelli M. R. Gallipoli F. C. Ponzo 《Bulletin of Earthquake Engineering》2010,8(3):693-703
The influence of vibrating buildings on the free-field ground motion could affect the earthquake recordings collected inside
or nearby the buildings. Some evidences are known for large structures, but also small buildings could adversely affect the
quality of the recordings. An example is given for a station of the Italian Accelerometric Network whose recordings show a
clear mark of the frequency of the host building. To tackle this problem in a more general way, we performed numerical simulations
whose first aim was to validate existing empirical evidence from a test site. Gallipoli et al. (Bull Seismol Soc Am 96:2457–2464,
2006) monitored a release test on a 2-storey R.C. building in Bagnoli (Italy), showing that a single vibrating building may
affect the “free-field” motion with an influence that reaches 20% of peak ground acceleration. We re-analysed the data of
that experiment following the Safak (Soil Dyn Earthq Eng 17:509–517, 1998) approach to building-soil motion, described as
propagation of up- and down-going S-waves. The numerical model is a chain of single degree of freedom oscillators, whose dynamic
behaviour depends on mass, stiffness and damping. The agreement between the synthetic and real data encouraged us to use this
model to reproduce generalised structures as systems with a single degree of freedom. We run multiple tests varying the distance,
between building and station, and the building-soil coupling, obtaining a statistical distribution of the influence of a single
vibrating building on free-field ground motion taking into account the distance. 相似文献
18.
Robert Tenzer Pavel Novák Ilya Prutkin Artu Ellmann Peter Vajda 《Studia Geophysica et Geodaetica》2009,53(2):157-167
To reduce the numerical complexity of inverse solutions to large systems of discretised integral equations in gravimetric
geoid/quasigeoid modelling, the surface domain of Green’s integrals is subdivided into the near-zone and far-zone integration
sub-domains. The inversion is performed for the near zone using regional detailed gravity data. The farzone contributions
to the gravity field quantities are estimated from an available global geopotential model using techniques for a spherical
harmonic analysis of the gravity field. For computing the far-zone contributions by means of Green’s integrals, truncation
coefficients are applied. Different forms of truncation coefficients have been derived depending on a type of integrals in
solving various geodetic boundary-value problems. In this study, we utilise Molodensky’s truncation coefficients to Green’s
integrals for computing the far-zone contributions to the disturbing potential, the gravity disturbance, and the gravity anomaly.
We also demonstrate that Molodensky’s truncation coefficients can be uniformly applied to all types of Green’s integrals used
in solving the boundaryvalue problems. The numerical example of the far-zone contributions to the gravity field quantities
is given over the area of study which comprises the Canadian Rocky Mountains. The coefficients of a global geopotential model
and a detailed digital terrain model are used as input data. 相似文献
19.
H.-W. Ma 《Stochastic Environmental Research and Risk Assessment (SERRA)》2002,16(6):464-478
There exist many sites with contaminated groundwater because of inappropriate handling or disposal of hazardous materials
or wastes. Health risk assessment is an important tool to evaluate the potential environmental and health impacts of these
contaminated sites. It is also becoming an important basis for determining whether risk reduction is needed and what actions
should be initiated. However, in research related to groundwater risk assessment and management, consideration of multimedia
risk assessment and the separation of the uncertainty due to lack of knowledge and the variability due to natural heterogeneity
are rare. This study presents a multimedia risk assessment framework with the integration of multimedia transfer and multi-pathway
exposure of groundwater contaminants, and investigates whether multimedia risk assessment and the separation of uncertainty
and variability can provide a better basis for risk management decisions. The results of the case study show that a decision
based on multimedia risk assessment may differ from one based on risk resulting from groundwater only. In particular, the
transfer from groundwater to air imposes a health threat to some degree. By using a methodology that combines Monte Carlo
simulation, a rank correlation coefficient, and an explicit decision criterion to identify information important to the decision,
the results obtained when uncertainty and variability are separate differ from the ones without such separation. In particular,
when higher percentiles of uncertainty and variability distributions are considered, the method separating uncertainty and
variability identifies TCE concentration as the single most important input parameter, while the method that does not distinguish
the two identifies four input parameters as the important information that would influence a decision on risk reduction. 相似文献
20.
Chu-Chih Chen Meng-Chiuan Shih Kuen-Yuh Wu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(1):21-31
The use of a physiologically based toxicokinetic (PBTK) model to reconstruct chemical exposure using human biomonitoring data,
urinary metabolites in particular, has not been fully explored. In this paper, the trichloroethylene (TCE) exposure dataset
by Fisher et al. (Toxicol Appl Pharm 152:339–359, 1998) was reanalyzed to investigate this new approach. By treating exterior chemical exposure as an unknown model parameter, a
PBTK model was used to estimate exposure and model parameters by measuring the cumulative amount of trichloroethanol glucuronide
(TCOG), a metabolite of TCE, in voided urine and a single blood sample of the study subjects by Markov chain Monte Carlo (MCMC)
simulations. An estimated exterior exposure of 0.532 mg/l successfully reconstructed the true inhalation concentration of
0.538 mg/l with a 95% CI (0.441–0.645) mg/l. Based on the simulation results, a feasible urine sample collection period would
be 12–16 h after TCE exposure, with blood sampling at the end of the exposure period. Given the known metabolic pathway and
exposure duration, the proposed computational procedure provides a simple and reliable method for environmental (occupational)
exposure and PBTK model parameter estimation, which is more feasible than repeated blood sampling. 相似文献