Environmental Systems Applications

Human Health Risk

Probabilistic Human Health Risk Assessment

Human Health Risk

Human health risk assessment and analysis involves evaluating the effect of toxins, contaminants and other environmental hazards on human health. This requires evaluation of both how humans might be exposed to the hazards (i.e., the environmental pathways through which they are exposed), as well as the health impact once they are exposed.

The challenge when evaluating such systems is to find an approach that can incorporate all the knowledge available to engineers and scientists into a quantitative framework that can be used to predict the potential risks associated with a product or project. To be effective, the framework needs to be both flexible (so that it can accurately represent the systems) and transparent (so the models can be easily explained to decision-makers and stakeholders).

Biosphere Model

By combining the flexibility of a general-purpose and highly-graphical probabilistic simulation framework with a specialized module to support mass transport modeling, GoldSim allows you to create realistic models of complex, real-world multi-media environmental systems. Using Monte Carlo simulation, you can explicitly represent the uncertainty inherent is these systems in order to carry out both exposure analysis and risk analysis. GoldSim has the power and flexibility to build "total system" models of many kinds of environmental systems, ranging from individuals to populations. In addition, GoldSim supports two-dimensional (nested) Monte Carlo simulation, allowing you to explicitly separate uncertainty and variability in your analyses.

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Technical Papers

  • Non-Adherence Tree Analysis (NATA)—An adherence improvement framework: A COVID-19 case study

    PLOS ONE – February 2021

    Ernest Edem Edifor, Regina Brown, Paul Smith, Rick Kossik

    Poor medication adherence is a global phenomenon that has received a significant amount of research attention yet remains largely unsolved. Medication non-adherence can blur drug efficacy results in clinical trials, lead to substantial financial losses, increase the risk of relapse and hospitalisation, or lead to death. The most common methods of measuring adherence are post-treatment measures; that is, adherence is usually measured after the treatment has begun. What the authors are proposing in this multidisciplinary study is a new technique for predicting the factors that are likely to cause non-adherence before or during medication treatment, illustrated in the context of potential non-adherence to COVID-19 antiviral medication. Fault Tree Analysis (FTA), allows system analysts to determine how combinations of simple faults of a system can propagate to cause a total system failure. Monte Carlo simulation is a mathematical algorithm that depends heavily on repeated random sampling to predict the behaviour of a system. In this study, the authors propose a new technique called Non-Adherence Tree Analysis (NATA), based on the FTA and Monte Carlo simulation techniques, to improve adherence. Firstly, the non-adherence factors of a medication treatment lifecycle are translated into what is referred to as a Non-Adherence Tree (NAT). Secondly, the NAT is coded into a format that is translated into the GoldSim software for performing dynamic system modelling and analysis using Monte Carlo. Finally, the GoldSim model is simulated and analysed to predict the behaviour of the NAT. NATA is dynamic and able to learn from emerging datasets to improve the accuracy of future predictions. It produces a framework for improving adherence by analysing social and non-social adherence barriers. Novel terminologies and mathematical expressions have been developed and applied to real-world scenarios. The results of the application of NATA using data from six previous studies in relation to antiviral medication demonstrate a predictive model which suggests that the biggest factor that could contribute to non-adherence to a COVID-19 antiviral treatment is a therapy-related factor (the side effects of the medication). This is closely followed by a condition-related factor (asymptomatic nature of the disease) then patient-related factors (forgetfulness and other causes). From the results, it appears that side effects, asymptomatic factors and forgetfulness contribute 32.44%, 22.67% and 18.22% respectively to discontinuation of medication treatment of COVID-19 antiviral medication treatment. With this information, clinicians can implement relevant interventions and measures and allocate resources appropriately to minimise non-adherence.

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  • Post-Closure Safety Assessment of Near Surface Disposal Facilities for Disused Sealed Radioactive Sources

    Nuclear Engineering and Design – March 2017

    Seunghee Lee and Juyoul Kim, FNC Technology Co.

    Great attention has been recently paid to the post-closure safety assessment of low- and intermediate-level radioactive waste (LILW) disposal facility for disused sealed radioactive sources (DSRSs) around the world. Although the amount of volume of DSRSs generated from industry, medicine and research and education organization was relatively small compared with radioactive wastes from commercial nuclear power plants, some DSRSs can pose a significant hazard to human health due to their high activities and long half-lives, if not appropriately managed and disposed. In this study, post-closure safety assessment was carried out for DSRSs generated from 1991 to 2014 in Korea in order to ensure long-term safety of near surface disposal facilities. Two kinds of disposal options were considered, i.e., engineered vault type disposal facility and rock-cavern type disposal facility. Rock-cavern type disposal facility has been under operation in Gyeongju city, republic of Korea since August 2015 and engineered vault type disposal facility will be constructed until December 2020 in the vicinity of rock-cavern disposal facility. Assessment endpoint was individual dose to the member of critical group, which was modeled by GoldSim, which has been widely used as probabilistic risk analysis software based on Monte Carlo simulation in the area of safety assessment of radioactive waste facilities.

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  • The Introduction of the Safety Assessment of HLW Disposal in 2014–2017 in China

    Proceedings of The 20th Pacific Basin Nuclear Conference. PBNC 2016. – February 2017

    Hong-hui Li, China Institute for Radiation Protection

    In China, “The Law on Prevention and Control for Radioactive Pollution” issued in 2003 determined that the high-level waste will be disposed in a deep central geological repository. The main work of China Institute for Radiation Protection (CNNC-mandated comprehensive research) about HLW disposal is safety assessment. In 2006–2010, the CIRP have done some of the works about safety criteria and safety requirements: public radiation protection for post-closure of repository: 0.3 mSv/a; timescale: 10,000a. The CIRP also have established SA methodology and routine. Some software about safety assessment such as AMBER, Ecolegy, GoldSim, ProFlow can be familiarly used. The main works in 2014–2017 about the safety assessment that will be done are the research of safety requirements of the EBS and host rock, the research of safety function of the EBS and host rock, establishing the safety indicators’ system of the EBS and host rock, establishing the FEPs list and the scenario analysis in the conceptual and planning stage, the near-field temperature simulation based on the conceptual design of the repository, and the safety assessment of Beishan Preliminary Repository. Some of the above-mentioned work details will be introduced in this paper.

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  • Quantitative Farm-to-Fork Human Norovirus Exposure Assessment of Individually Quick Frozen Raspberries and Raspberry Puree

    International Journal of Food Microbiology – February 2017

    Jacxsens L, Stals A, De Keuckelaere A, Deliens B, Rajkovic A, and Uyttendaele M, Ghent University

    A quantitative human norovirus (NoV) exposure model describing transmission of NoV during pre-harvest, harvest and further processing of soft red fruits exemplified by raspberries is presented. The outcomes of the model demonstrate the presence of NoV in raspberry puree or individual quick frozen (IQF) raspberry fruits and were generated by Monte Carlo simulations by combining GoldSim and @Risk software. This farm-to-fork model is a useful tool for evaluating NoV mitigation strategies in the soft red fruit supply chain.

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  • Sorbent Materials for Rapid Remediation of Wash Water during Radiological Event Relief

    Chemosphere – November 2016

    Jolin WC, University of Connecticut; Kaminski M, Argonne National Laboratory

    Procedures for removing harmful radiation from interior and exterior surfaces of homes and businesses after a nuclear or radiological disaster may generate large volumes of radiologically contaminated waste water. Rather than releasing this waste water to potentially contaminate surrounding areas, it is preferable to treat it onsite. Retention barrels are a viable option because of their simplicity in preparation and availability of possible sorbent materials. This study investigated the use of aluminosilicate clay minerals as sorbent materials to retain (137)Cs, (85)Sr, and (152)Eu. To simulate flow within retention barrels, vermiculite was mixed with sand and used in small-scale column experiments. The GoldSim contaminate fate module was used to model breakthrough and assess the feasibility of using clay minerals as sorbent materials in retention barrels.

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  • Preliminary Post-closure Safety Assessment of Disposal Options for Disused Sealed Radioactive Source

    Economic and Environmental Geology – August 2016

    Seunghee Lee, Juyoul Kim and Sukhoon Kim, FNC Technology Co.

    Disused Sealed Radioactive Sources (DSRSs) are stored temporally in the centralized storage facility of Korea Radioactive Waste Agency (KORAD) and planned to be disposed in the low- and intermediate-level radioactive waste (LILW) disposal facility in Gyeongju city. In this study, preliminary post-closure safety assessment was performed for DSRSs in order to draw up an optimum disposal plan. Two types of disposal options were considered, i.e. engineered vault type disposal and rock cavern type disposal which were planned to be constructed and operated respectively in LILW disposal facility in Gyeongju city. Assessment end-point was individual effective dose of critical group and calculated by using GoldSim code.

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  • A Preliminary Comparison Study of Two Options for Disposal of High-Level Waste

    Progress in Nuclear Energy – July 2016

    Youn-Myoung Lee, Heui-Joo Choi, and Kyungsu Kim, Korea Atomic Energy Research Institute (KAERI)

    To compare two options for disposal of spent nuclear fuels (SFs) a generic GoldSim model for deep boreholes for disposal (DBD) of SFs was developed. As a desktop study, nuclide release and transport from a DBD after the closure of a repository were roughly evaluated and compared to a KBS-3 type disposal in a less deep geological repository (DGD). An assessment result from the DBD is shown to be remarkable and seems to give a sufficient radiological safety margin, compared to the DGD, even though this study was done in a very straightforward manner. A remarkable sensitivity of the travel lengths involved in the fractured geological media around the DBD to the exposure dose rates are not observed with rather fast and short travel times for non-sorbing nuclides with long-half lives.

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  • Progress of the Long-Term Safety Assessment of a Reference Disposal System for High Level Wastes in Korea

    Progress in Nuclear Energy – July 2016

    Jongtae Jeong, Youn-Myoung Lee, Jung-Woo Kim, Dong-Keun Cho, Nak Yul Ko, and Min Hoon Baik, Korea Atomic Energy Research Institute (KAERI)

    KAERI developed a reference repository system for the disposal of radioactive wastes resulting from the pyroprocessing of PWR spent nuclear fuels (A-KRS; Advanced Korean Reference Disposal System). To check the design feasibility of this system, we developed a total system performance assessment (TSPA) tool using Goldsim program and assessed the exposure dose rates for the reference scenario and three alternative scenarios such as earthquake, well intrusion, and initial defect of waste packages by using this tool. And then, we compared the exposure dose rates for each scenario with a draft supplementary safety goal, 10 mSv/yr, which was suggested by the regulatory body in Korea.

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  • Long-term Environmental Assessment of Waste from PyroGreen System

    Procedia Chemistry – January 2016

    Heejae Ju, Inhye Hahm, Sungjune Sohn, and Il Soon Hwang, Seoul National University

    We have conducted a long-term environmental assessment of a geological repository for Intermediate Level Wastes (ILW) arising from PyroGreen processes that has been developed to decontaminate all HLW from the pyrochemical partitioning of spent nuclear fuels (SNF). PyroGreen process has been designed so that final ILW can meet conservative acceptance criteria such as one established for the Waste Isolation Pilot Plant (WIPP) in U.S.A. The nuclide inventory of final vitrified PyroGreen waste is calculated using ORIGEN 2.1 based on the design decontamination factor of PyroGreen processes applied to 18,171 metric tons of PWR SNF with 45 GWD/MTU burnup. Using GoldSim model, the environmental impact of ILW upon geological disposal at an intermediate depth. Among radioactive nuclides, Ra226, Rn222 and Sn126 are identified as key contributors to radiological dose for general public. The environmental impact of PyroGreen wastes satisfies the Korean dose limit of 0.1 mSv/year with sufficiently high margin. Sensitivity studies have shown that the predicted dose can vary significantly by distribution coefficient of Ra226 and Rn222, solubility limit of Se79.

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  • Influence of Particle Size and Organic Carbon Content on Distribution and Fate of Aliphatic and Aromatic Hydrocarbon Fractions in Chalks

    Environmental Technology & Innovation – October 2015

    Xingtao Cao, Tracey Temple, Xingang Li, Frédéric Coulon, Hong Sui, Tianjin University and Cranfield University

    In this study, the fate and distribution of the aliphatic and polycyclic aromatic hydrocarbons (PAHs) of diesel fuel in chalk aquifer was investigated using a series of leaching column tests and then modelled using the Contaminant Transport module of the Goldsim software. Specifically the influence of chalk particle size on the behaviour and fate of the hydrocarbons was investigated. The numerical results and the Monte Carlo analysis showed that the migration of the alkanes and PAHs is greatly retarded by the organic carbon in chalk. It is also observed that the initial mass of the alkanes and PAHs and their respective partition coefficients are important for the decaying of the source at the surface immediately after the spill and the rate-limited dissolution is responsible for entrapping the hydrocarbons in the top layer of the chalk. Overall these results can help to better inform risk assessment and help decision for the remediation strategy.

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  • A Quantitative Exposure Model Simulating Human Norovirus Transmission During Preparation of Deli Sandwiches

    International Journal of Food Microbiology, Vol. 196, Pgs. 126-136 – March 2015

    Stals A, Jacxsens L, Baert L, Uyttendaele M, Ghent University, Van Coillie E, Flemish Government, Institute for Agricultural and Fisheries Research.

    This journal article describes a study that simulates human noroviruses (HuNoV) transmission during the preparation of deli sandwiches in a sandwich bar. A quantitative exposure model was developed by combining the GoldSim and @Risk® software packages.

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  • A Comparative Study Between GoldSim and AMBER Based Biosphere Assessment Models for an HLW

    Transactions of the Korean Nuclear Society Autmn Meeting, PyeongChang, Korea – October 2007

    Youn-Myoung Lee and Yongsoo Hwang, Korea Atomic Energy Research Institute

    To demonstrate the performance of a repository, GoldSim was used to examine the dose exposure rate to people due to long-term nuclide releases from a high-level waste repository and the results are compared to that of a similar model built in AMBER. The GoldSim model integrates the results of complex nuclide transport models through engineered barriers and geological fractured rock media surrounding an HLW repository site for a consecutive transport through a biosphere.

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  • Prevention of Food Worker Transmission of Foodborne Pathogens

    Food Service Technology Volume 4 Issue 1, pgs. 31-49 – March 2004

    Barry Michaels and Cheryll Keller, The Michaels Group; Matthew Blevins, University of Florida; Greg Paoli and Todd Ruthman, Decisionalysis Risk Consultants; Ewen Todd, Michigan State University; Christopher Griffith, University of Wales Institute

    This paper describes the use of GoldSim and other risk analysis tools to model pathogen transmission in food handling. These models were used to explore the effectiveness of different food safety measures.

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