Multimedia Environmental Model Research Articles

Aggregate risk assessment for multi-route exposure to hazardous chemicals caused by chemical accidents, with a focus on toluene

Chemical accidents significantly impact environmental and human health. However, studies investigating the impacts of such accidents have primarily focused on single-route exposures, potentially underestimating the extent of damage. This study aimed to conduct an aggregate risk assessment for multi-route exposure to hazardous chemicals to ensure systematic and rational management of the health impacts on residents exposed to chemical accidents, considering the behavior of a hazardous chemical from a chemical accident within environmental media. Drawing upon a real chemical accident that occurred in Siheung, Gyeonggi-do, in 2019, leakage of 500 L of toluene over an hour was assumed. Employing a multimedia environmental dynamics model, the time-dependent concentrations across various environmental media were calculated, and the average daily dose (ADD), hazard quotient (HQ), and hazard index (HI) for each exposure route included in the multi-route exposure assessment were derived. Health risks were deemed present if the calculated HQ and HI values exceeded the threshold of 1. The results indicated the highest ADD values among the 0–9 age group, with inhalation exposure registering the highest ADD across all exposure routes. However, no significant health risks were observed, with both HQ and HI values not exceeding 1. This aggregate risk assessment approach is proposed as an effective preliminary evaluation method for health impact assessments in areas affected by chemical accidents.Graphical

Brominated Flame Retardants (BFRs) in China Over the Past Half-Century: Stocks, Flows, Fates, and Ecological Risks.

China is a significant producer and consumer of various brominated flame retardants (BFRs), raising environmental concerns due to their widespread presence and potential threats to ecosystems and organisms. This study adopts a life cycle perspective, combining material flow analysis, multimedia environmental modeling, and ecological risk assessment to systematically analyze the substance metabolism and ecological risks of six BFR types in China from 1970 to 2021. The findings reveal that China's cumulative BFR consumption reached 3.3 Mt, with the electronics sector being the predominant contributor at 52.1%. Consequently, 1.5 kt of BFRs were released into the environment, with 24.9%, 31.5%, and 43.6% being discharged into the air, water, and soil, respectively. Notably, the proportion of novel BFRs in emissions has steadily increased over the years, exemplified by the increase in decabromodiphenyl ethane (DBDPE) from 21.3% in 2010 to 30.1% in 2021. Geographically, BFR concentrations are higher in the eastern and southwestern regions compared to those in the northwest. Presently, certain BFRs like tetrabromobisphenol A (TBBPA) and DBDPE exhibit moderate to high ecological risks, primarily concentrated in the Shandong and Sichuan provinces. A combination of efficient recycling, emission control, and substitution with novel flame-retardant can minimize the exposure of BFRs to the environment and organisms.

Soil's Hidden Power: The Stable Soil Organic Carbon Pool Controls the Burden of Persistent Organic Pollutants in Background Soils.

Persistent organic pollutants (POPs) tend to accumulate in cold regions by cold condensation and global distillation. Soil organic matter is the main storage compartment for POPs in terrestrial ecosystems due to deposition and repeated air-surface exchange processes. Here, physicochemical properties and environmental factors were investigated for their role in influencing POPs accumulation in soils of the Tibetan Plateau and Antarctic and Arctic regions. The results showed that the soil burden of most POPs was closely coupled to stable mineral-associated organic carbon (MAOC). Combining the proportion of MAOC and physicochemical properties can explain much of the soil distribution characteristics of the POPs. The background levels of POPs were estimated in conjunction with the global soil database. It led to the proposition that the stable soil carbon pools are key controlling factors affecting the ultimate global distribution of POPs, so that the dynamic cycling of soil carbon acts to counteract the cold-trapping effects. In the future, soil carbon pool composition should be fully considered in a multimedia environmental model of POPs, and the risk of secondary release of POPs in soils under conditions such as climate change can be further assessed with soil organic carbon models.

Evaluation of the environmental exposure risks of pesticides used in vegetable production in Türkiye

In this study, first, a list of pesticides that can potentially pose environmental exposure risks was compiled by analyzing the recent literature on residue levels in fresh vegetables produced in Türkiye. Then, by using the fundamental environmental partitioning properties of these pesticides, their potential multi-media environmental distributions were assessed. Acetamiprid, chlorpyrifos, and pyridaben were among the pesticides that frequently exceeded the residual limit values. Multi-media environmental modeling was conducted for these three pesticides using an evaluative four-compartment (air, soil, water, sediment) model. Compartmental distributions, inter-compartmental mass transfer rates, advective, and reactive losses were estimated for the selected pesticides after their simulated application to soil. The ranking of overall persistence among the pesticides was found to be pyridaben > chlorpyrifos > acetamiprid. The percentage mass distribution of acetamiprid in water was higher due to its low volatility and high solubility. The overall persistence of chlorpyrifos was limited by its higher partitioning to air although it is more persistent than pyridaben in other compartments. To investigate the residue dynamics of the three pesticides in tomato crops, temporal changes in harvest fractions were compared using the regression equations of the crop model dynamiCROP. Acetamiprid was estimated to be taken up at higher rates in tomatoes after initial application. The residue dynamics of chlorpyrifos and pyridaben were found to be similar. The quantitative methods in this study can be used to assess the environmental risks associated with commonly used pesticides in Türkiye and to address the issue of exceeding residue limits in agricultural products.

Computational Nanotoxicology Models for Environmental Risk Assessment of Engineered Nanomaterials.

Although engineered nanomaterials (ENMs) have tremendous potential to generate technological benefits in numerous sectors, uncertainty on the risks of ENMs for human health and the environment may impede the advancement of novel materials. Traditionally, the risks of ENMs can be evaluated by experimental methods such as environmental field monitoring and animal-based toxicity testing. However, it is time-consuming, expensive, and impractical to evaluate the risk of the increasingly large number of ENMs with the experimental methods. On the contrary, with the advancement of artificial intelligence and machine learning, in silico methods have recently received more attention in the risk assessment of ENMs. This review discusses the key progress of computational nanotoxicology models for assessing the risks of ENMs, including material flow analysis models, multimedia environmental models, physiologically based toxicokinetics models, quantitative nanostructure-activity relationships, and meta-analysis. Several challenges are identified and a perspective is provided regarding how the challenges can be addressed.

Implications of Extended Environmental Multimedia Modeling System (EEMMS) on Water Allocation Management: Tritium Numerical Case Study

Tritium waste deposition in air-unsaturated groundwater zones poses great challenges to optimal water allocation. This paper reviews the research progress of air-unsaturated-groundwater interaction. Traditional interaction studies typically model the fate and migration of pollutants in different regions. This can lead to biased results and simulation errors. The development of air-unsaturated-ground integrated modeling will be a breakthrough and a hotspot in tritium management. In this paper, the fate and migration of tritium leakage is further studied using the existing extended Environment Multimedia Modeling System (EEMMS). Moreover, to better understand its distribution in three zones, using tritium as a typical pollutant, it is necessary to consider its characteristics in different zones, especially its migration from unsaturated zones to groundwater and air zones. The result shows that the tritiated water vapor transfer in unsaturated groundwater areas decreases and part of the tritiated water vapor transfers to atmospheric areas as tritiated gas vapor. Compared with the analytical test accuracy (5 pCi mL−1), the accuracy of the tritium modeling using the finite element method can reach the minimum concentration limit of 0 pCi mL−1. The study of its distribution in air-unsaturated-groundwater zones can provide reference for other similar tritium management or NAPLs distribution across multimedia area.

Expected Risk as basis for assessment of safe use of chemicals

This paper describes a straightforward modeling procedure to derive ‘expected risk’ (ER) of chemical substances. Starting from proposed use volumes, intended uses, physical and chemical substance properties and toxicity information, the procedure combines multimedia environmental fate modeling with species sensitivity modeling to derive the probability that exposure concentrations exceed critical effect concentrations. The procedure was tested on 1977 so-called mono-constituent organic chemicals that had been registered to be marketed in the EU, after ‘possibility to be used safely’ had been demonstrated by showing that the possible Risk Quotients (RQ) defined as PEC/PNEC ratios (Predicted Exposure Concentration & Predicted No Effect Concentration) were expected to remain below the value of 1, as required by REACH. It appears from this study that (i) RQ and ER of chemicals can be calculated readily, reliably, transparently and reproducibly, that (ii) both RQ and ER can be used to assess whether a new chemical may exceed a chosen acceptability level, but that (iii) in addition ER can be straightforwardly used to rank chemicals according to expected environmental safety. In conclusion, the paper states that modeling ER of chemicals (instead of estimating RQ values), could strengthen the scientific basis of environmental risk assessment for use in REACH. The paper further recommends that more robust environmental risk calculation can be done by using acute EC50, instead of chronic NOEC as critical effect concentration.

Coupled Dynamic Material Flow, Multimedia Environmental Model, and Ecological Risk Analysis for Chemical Management: A Di(2-ethylhexhyl) Phthalate Case in China.

Di(2-ethylhexhyl) phthalate (DEHP) is a widely used plasticizer that has adverse effects on ecosystems and human health. However, data about its stocks, flows, emission rates, as well as ecological risks are generally unknown in China, one of the world's largest producers of chemicals including DEHP, limiting sound management of chemicals. Herein, dynamic material flow analysis, coupled with a multimedia environmental model and ecological risk analysis, was performed to fill the data gap about DEHP in China mainland from 1956 to 2020. Results indicate that the in-use stocks of DEHP increased from 6.54 × 106 kg in 1956 to 8.40 × 109 kg in 2020. With growth in the emission rates, DEHP concentrations in air, soil, water, and sediment kept increasing from 1956 to 2010, which declined after 2010 and regrew after 2015. Sediment was a main sink of DEHP with the highest ecological risk quotient of >10 after 1999, necessitating measures for controlling the risk, for example, technology innovation to reduce DEHP emission rates, and substitution of DEHP with low-toxic alternatives. The coupled models that connect socio-economic data with ecological risk output may provide a systematic methodology for verification of the data necessary for risk control of chemicals.

A regional numerical environmental multimedia modeling approach to assess spatial Eco-Environmental exposure risk of perfluorooctane sulfonate (PFOS) in the Pearl river basin.

This paper presents a novel numerical environmental multimedia modeling system (RNEMM) for assessing the environmental fate of emerging organic contaminants and their relative health risk at a regional scale. The RNEMM is developed based on an integrated numerical algorithm that comprises four sub-models: a river network simulation module, a gaseous phase simulation module, a mass balance based simulation module for soil compartment, and a food web analysis module. This RNEMM has been applied to simulate the spatial distribution of PFOS and assess the consequent health risks for a central water basin region of the Pearl River in China. The study region includes the urban areas of Guangzhou, Foshan, and Dongguan Cities with emission sources of PFOS, which was detected in local water, sediments, and air environment. The spatial concentration distributions of PFOS in water, sediment, air, soil, and various fish species are examined based on RNEMM and compared with the measured data. With a focus on water environment, it shows that the simulated results essentially agree well with measured concentrations. Comparing the simulated results and the measured data collected in 2013, the relative errors are mostly less than 40 % in the surface water and sediment zones for this regional scale field study. Whereas the relative error in the atmosphere zone is less than 5%. In addition, the health risk assessment for children and adults is conducted based on the RNEMM approach. The hazard quotient (HQ) values for the 95th percentile in most subareas of the study region are higher than 0.1, showing a low-risk level for the study period. The results indicate that the RNEMM is a useful modeling tool to manage the environmental and health risks associated with emerging contaminants on regional air, water, soil, and ecosystem at an adequate spatial-temporal resolution.

Acute and chronic health risk assessment for inhalation and ingestion exposure in acrylic acid leak accidents

We established a hypothetical acrylic acid leak accident scenario, conducted a health risk assessment of local residents, and compared an actual accident case to the hypothetical scenario. The exposed subjects were divided into four age groups, and a noncarcinogenic health risk assessment was conducted for inhalation and soil ingestion. In the hypothetical scenario, 40 tons of acrylic acid was leaked in Ulsan for 1 h from midnight on January 1, 2017. In the actual accident case, 3 L of acrylic acid was leaked in Hwaseong, Gyeonggi Province, for 1 h from 11:00 am on March 5, 2020. The environmental concentration of acrylic acid was calculated using the dynamic multimedia environmental model. Noncarcinogenic assessment of the hypothetical scenario showed the hazard quotient exceeded 1 across all age groups, suggesting that a health risk is likely to occur due to inhalation exposure to acrylic acid resulting from a chemical accident. In addition, Hazardacute exceeded 1 until 2 h after the accident under the hypothetical scenario, indicating the likelihood of a health risk. Thus, we propose a methodology that can assess changing concentrations in a hazardous chemical leak from a chemical accident based on the time, place, the chemical’s behaviors in different environmental media, and the health risk posed by the exposure of the chemical to local residents in the area affected by the accident.

A multimedia Environmental Model to Predict the Lead Concentration in Children’s Blood Near Al-Dorah Refinery in Baghdad

Lead-contaminated water, soil, and air have been perceived as potential sources of lead exposure for a considerable length of time, which continues to threaten human health; particularly that of young children. An Integrated Exposure, Uptake, and Biokinetic (IEUBK) as a human health risk model were applied to predict the Blood lead levels (BLLs) in children. A variety of data for air, soil, and water were obtained from the industrial region in Al-Dorah city in Baghdad for the period 2012- 2014. The result found that the predicted BLLs value of 11.17 μg/dL obtained from the IEUBK model was exceeding the agency’s threshold of concern of 10 μg/jdL which was considered as the lowest level of concern for BLL in children, this result of the IEUBK model was in agreement with the actual value of BLLs which were taken from previous literature for 24 blood samples of school children matched for age curried out in the same Al-Dorah region. This technique propels logical comprehension of the connection between BLLs in children and environmental media in both air and soil for the pollute condition. It can control national health-based benchmarks for lead and related community public health decisions.

Application of an environmental multimedia modeling system for health risk assessment: Key influencing factors and uncertainties research.

In this paper, an environmental multimedia modeling system (EMMS) that combines a risk assessment with a Monte Carlo method (MCM) was used to explore the interaction between groundwater and surface water with respect to chemical exposure and risk. The EMMS-MCM simulations incorporated several key influencing factors that are inherent in traditional predictions of subsurface and surface-water interactions, including soil permeability coefficients and parameters such as hydraulic conductivity, density, recharge, layers, and depth. These influencing factors are generally associated with the largest sources of uncertainty in modeling and pose significant challenges to water management and to the optimal allocation of water resources. A case study involving benzene at the Trail Road landfill site located in the Ottawa-Carlton area of Canada is presented to illustrate the use of the EMMS-MCM approach. The model results are verified by comparisons to the results of groundwater and surface-water investigations in the landfill. The EMMS-MCM results are evaluated using a risk quotient (RQ) risk assessment method to quantify environmental risk. The EMMS-MCM simulations can be used to support hazardous field work and contribute to environmental management by predicting the possible consequences of hazardous chemical contaminations in surface waters and groundwater. The integration of the EMMS-MCM and RQ approaches represents an appropriate tool for the accurate assessment of long-term pollutant risks and environmental management of surface- and groundwater resources. Integr Environ Assess Manag 2021;17:877-886. © 2021 SETAC.

Discussion of “Examining Fate and Transport of Heavy Metal in Landfill Site through Numerical Environmental Multimedia Modeling Approach” by Jinxin Dong, Zhi Chen, Ke Wang, Yi Han, and Jianbo Guo

Discussion of “Examining Fate and Transport of Heavy Metal in Landfill Site through Numerical Environmental Multimedia Modeling Approach” by Jinxin Dong, Zhi Chen, Ke Wang, Yi Han, and Jianbo Guo

Health risk assessment for multimedia exposure of formaldehyde emitted by chemical accident.

This study was conducted to provide basic data for chemical accident response by assessing the health risks of residents living near a chemical accident site due to long-term exposure. The study considered the temporal concentration changes of the leaked chemical (i.e., its behavior in the environment and dilution) until its extinction. A virtual chemical accident was assumed, in which 40 t of formaldehyde was accidentally discharged for 1 h in Ulsan Metropolitan City, Korea. Formaldehyde concentrations over time in each environmental medium after the accident were calculated using a multimedia environmental dynamics model. Exposure subjects divided into four age groups were considered. Carcinogenic risks due to respiration and non-carcinogenic risks due to soil intake were assessed. For all the age groups, the excess cancer risk did not exceed 1.0 × 10-6, indicating that no harmful health impact was caused by inhalation exposure to formaldehyde. The hazard index exceeded 1 for all the age groups, confirming that harmful health impacts were caused by exposure to soil containing the formaldehyde. This study is the first to assess chronic health risks by reflecting long-term residual and temporal concentration changes of a pollutant released in a chemical accident in each environmental medium until its extinction. This work is also significant in that it reflects the exposure characteristics of the toxic chemical.

Study fate of pollutants due to oil spill in sea water through multimedia environmental modeling

Due to massive shipment of oil across the border, spill disaster occurs which results in release of pollutants posing both short- and long-term threats to ambient environment. In this paper, an integrated oil spill multimedia model framework is conceptualized which comprises Fugacity and Hydrocarbon Spill Screen Model. The aim of the model development is to predict the fate and transport mechanism of oil spill-based pollutants across multimedia i.e., water, air, sediments, and aquatic biota. Hydrocarbon spill screen model is used to identify mass flux and predict concentration of pollutants in receptor medium i.e., in surface water. Whereas, fugacity level I model is applied to determine multiphase transfer rates of contaminants from one medium to another. The developed framework is applied to a case study to explore the feasibility of a model. Three different poly-aromatic hydrocarbons (naphthalene, benzene, and toluene) are considered for model simulation. The results from modeling study reveal that 30,000 tons of crude oil spillage contribute 58% release of naphthalene pollutant in receiving water body. Whereas, other two constituents i.e., benzene and toluene are abundantly present in air phase contributing 83% and 85% release in air, respectively. Overall, naphthalene remained persistent in environment for around 7 years, polluting most of bottom sediments through advection phenomena and by bio-accumulating in aquatic species. Thus, the model provides useful outcomes to analyze the fate of pollutants released in environment because of spillage and help to select remediation method for spills incidents in time.

Influence of Temperature Change on the Fate of Chlorinated Persistent Organic Pollutants (POPs): A Preliminary Study

In this study, the influence of climate change on the fate of chlorinated Persistent Organic Pollutants (POPs) in Ulsan, South Korea was evaluated using a multimedia environmental fate model (CoZMo-POP 2). PCB-28 and PCB-153, representative POPs, were selected for the modeling with the temperature changes (±5.0°C and ±2.5°C). Results indicate that the long-term trends of PCB concentrations reflect an emission scenario, with the exception of PCB-153 in soil and sediment. In particular, when the temperature increased, the concentrations of PCBs in the atmosphere also increased; however, those of PCBs in other media (canopy, soil, water, and sediment) decreased. In contrast, the concentration of PCB-153 in a deciduous canopy increased with an increase in temperature due to the high deposition velocity. Due to the temperature changes, the accumulation amounts of PCB-153 showed larger variations from the current levels in the atmosphere, whereas PCB-28 showed larger variations in other media. More specifically, high-chlorinated PCBs mainly accumulated in forest soil, but their levels in the atmosphere demonstrated the high impact caused by the temperature changes. Low-chlorinated PCB levels in the canopy and atmosphere were also highly impacted by the temperature changes. The results of this study can be applied to establish long-term monitoring plans and regulatory policies of POPs according to climate changes such as increases in temperatures. Key Words: POPs, PCBs, Climate change, Multimedia environmental model, CoZMo-POP 2

Development on Health Risk Assessment Method for Multi-Media Exposure of Hazardous Chemical by Chemical Accident

In this study, a long-term health risk assessment was conducted for complex, multimedia exposure where the exposure duration was set for the leak of a hazardous chemical spilled after an accident. The study designed a virtual chemical accident scenario where 40 tons of benzyl chloride leaked in a factory inside the Ulsan Petrochemical Industrial Complex for one hour on 1 January 2017. Using a multimedia environmental dynamics model, benzyl chloride concentrations in air and soil were estimated. The time when the atmospheric concentration was less than or equal to the background concentration was recorded as the end point. An assessment of the cancer risk via soil ingestion was carried out after dividing the subjects into four age groups (0–9 years; 10–18 years; 19–65 years; >65 years). All age groups showed an increased cancer risk where the values exceeded 1.0 × 10−6. The 0–9 years age group showed the largest distribution (4.27% of the total area) with the highest maximum and mean values. The distribution maps for all age groups exhibited a trend towards the southeast of the accident site.

Examining Fate and Transport of Heavy Metal in Landfill Site through Numerical Environmental Multimedia Modeling Approach

AbstractIn this study, the environmental multimedia model (EMM) is extended for assessing the heavy metal in a contaminated site. Using numerical analysis, the EMM is advanced as a numerical EMM sy...

Extended environmental multimedia modeling system assessing the risk carried by pollutants in interacted air-unsaturated-groundwater zones

Simulation of the transport of hazardous pollutants in a variety of media is a challenge. In this paper, a novel Extended Environment Multimedia Modeling and Analysis System (EEMMS) for migration of pollutants from landfill through unsaturated site to groundwater is presented. The developed EEMMS consists of four pathways modules: air, landfill, unsaturated zone and groundwater zone. The finite element method in EEMMS framework is used to analyze these four pathways and the results are compared to the finite difference model and analytical model. The effectiveness of EEMMS has been verified through a case study of Trail Road Landfill site. The simulation of uncertainty was conducted with a quantitative technique of Monte Carlo Method. The Risk Quotient (RQ) results show that the low-risk area covers 10,000 square meters, where the predicted concentrations of benzene are between 1 and 1.2 μg L−1. However, the high-risk area covers almost 200,000 square meters. Contrary to FEM, the majority of the FDM and analytical predictions were too high and fell outside the high boundary of the experimental result. The EEMMS is a unique risk assessment tool that can be used for impacts on water resource quality, biodiversity, fate of pollutants in ecosystem, climate change, etc.

A regional spatial environmental multimedia modeling (RSEMM) approach for assessing the risk of antibiotics in river basin system – a China case study

In this paper, a regional spatial environmental multimedia modeling (RSEMM) approach is developed based on the integration of an environmental multimedia method (EMM) and a numerical water quality model. Emissions, inter-media mass transfer, physical transport and degradation processes are considered in the modeling system. The RSEMM approach is applied to the Beijing-Tianjin area in China, where there are many antibiotic emission sources throughout the Haihe River Basin including six streams. The antibiotic sulfadiazine (SDZ) is selected as the target contaminant in this basin region, including the urban area of Tianjin City. The predicted SDZ concentrations in the water and sediment zones align well with the reported monitoring data. A sensitivity analysis, using the Morris screening method, shows that flow rate and active sediment depth are the significant influential parameters for the regional water and sediment zones. Two modeling scenarios are further performed to assess health risks. They show that the SDZ concentrations and risks in the impacted environmental media could be reduced by possible mitigation actions. The RSEMM approach can also be applied to find the source-response relation in order to control other emerging contaminants in a complicated environmental multimedia site.