Source-to-exposure assessment with the Pangea multi-scale framework - case study in Australia

Spatially resolved environmental fate models: A review

Spatially resolved environmental models are important tools to introduce and highlight the spatial variability of the real world into modeling. Although various spatial models have been developed so far, yet the development and evaluation of these models remain a challenging task due to several difficulties related to model setup, computational cost, and obtaining high-resolution input data (e.g., monitoring and emission data). For example, atmospheric transport models can be used when high resolution predicted concentrations in atmospheric compartments are required, while spatial multimedia fate models may be preferred for regulatory risk assessment, life cycle impact assessment of chemicals, or when the partitioning of chemical substances in a multimedia environment is considered. The goal of this paper is to review and compare different spatially resolved environmental models, according to their spatial, temporal and chemical domains, with a closer insight into spatial multimedia fate models, to achieve a better understanding of their strengths and limitations. This review also points out several requirements for further improvement of existing models as well as for their integration.

Research on green technologies for immobilizing mercury in waste to minimize chemical footprint

This paper is devoted to the use of the principles of green chemistry in the search for technologies to reduce the chemical footprints of areas. The chemical footprint for mercury and its compounds was taken as an example to study. These chemicals belong to priority pollutants and their ever-increasing amounts in the environment have caused concern around the world, which is reflected in the adoption of the Minamata Convention. The Minamata Convention aims to protect human health and the environment from anthropogenic releases of mercury and mercury compounds. This Convention is an important component of efforts to achieve sustainable, inclusive and resilient human development through SDGs, which were adopted in September 2015 and especially SDG Goal 12: Ensure sustainable consumption and production patterns. Relevancy of this work is due to the need for the adopting of a series of measures to withdraw some mercury-containing goods from the production cycle. Also, one of the most important statements of the Convention is in reference to the issue of mercury contamination when recycling mercury. An important aspect of the work described in this paper is the reduction of mercury pollution from mercury-containing waste products by the development of technology in accordance with the principles of green chemistry. These are energy-efficient and without waste -water discharge technology. The main result of this work is the fundamental research for a transformation of elemental mercury and its compounds into less dangerous forms for the human body and the environment, providing a guaranteed absence of mercury-containing waste in the atmosphere and water systems. Various conditions for reaction of the immobilization of metallic mercury in mercury-containing wastes were investigated and it was established that it proceeded best under the following conditions:

Overview and recommendations for regionalized life cycle impact assessment

PURPOSE

Regionalized life cycle impact assessment (LCIA) has rapidly developed in the past decade, though its widespread application, robustness, and validity still faces multiple challenges. Under the umbrella of UNEP/SETAC Life Cycle Initiative, a dedicated cross-cutting working group on regionalized LCIA aims to provides an overview of the status of regionalization in LCIA methods. We give guidance and recommendations to harmonize and support regionalization in LCIA for developers of LCIA methods, LCI databases, and LCA software.

METHOD

A survey of current practice among regionalized LCIA method developers was conducted. The survey included questions on chosen method spatial resolution and scale, the spatial resolution of input parameters, choice of native spatial resolution and limitations, operationalization and alignment with life cycle inventory data, methods for spatial aggregation, the assessment of uncertainty from input parameters and model structure, and variability due to spatial aggregation. Recommendations are formulated based on the survey results and extensive discussion by the authors.

RESULTS AND DISCUSSION

Survey results indicate that majority of regionalized LCIA models have global coverage. Native spatial resolutions are generally chosen based on the availability of global input data. Annual modelled or measured elementary flow quantities are mostly used for aggregating characterization factors (CFs) to larger spatial scales, although some use proxies, such as population counts. Aggregated CFs are mostly available at the country level. Although uncertainty due to input parameter, model structure, and spatial aggregation are available for some LCIA methods, they are rarely implemented for LCA studies. So far, there is no agreement if a finer native spatial resolution is the best way to reduce overall uncertainty. When spatially differentiated models CFs are not easily available, archetype models are sometimes developed.

CONCLUSIONS

Regionalized LCIA methods should be provided as a transparent and consistent set of data and metadata using standardized data formats. Regionalized CFs should include both uncertainty and variability. In addition to the native-scale CFs, aggregated CFs should always be provided, and should be calculated as the weighted averages of constituent CFs using annual flow quantities as weights whenever available. This paper is an important step forward for increasing transparency, consistency and robustness in the development and application of regionalized LCIA methods.

Advancements in Life Cycle Human Exposure and Toxicity Characterization

BACKGROUND

The Life Cycle Initiative, hosted at the United Nations Environment Programme, selected human toxicity impacts from exposure to chemical substances as an impact category that requires global guidance to overcome current assessment challenges. The initiative leadership established the Human Toxicity Task Force to develop guidance on assessing human exposure and toxicity impacts. Based on input gathered at three workshops addressing the main current scientific challenges and questions, the task force built a roadmap for advancing human toxicity characterization, primarily for use in life cycle impact assessment (LCIA).

OBJECTIVES

The present paper aims at reporting on the outcomes of the task force workshops along with interpretation of how these outcomes will impact the practice and reliability of toxicity characterization. The task force thereby focuses on two major issues that emerged from the workshops, namely considering near-field exposures and improving dose–response modeling.

DISCUSSION

The task force recommended approaches to improve the assessment of human exposure, including capturing missing exposure settings and human receptor pathways by coupling additional fate and exposure processes in consumer and occupational environments (near field) with existing processes in outdoor environments (far field). To quantify overall aggregate exposure, the task force suggested that environments be coupled using a consistent set of quantified chemical mass fractions transferred among environmental compartments. With respect to dose–response, the task force was concerned about the way LCIA currently characterizes human toxicity effects, and discussed several potential solutions. A specific concern is the use of a (linear) dose–response extrapolation to zero. Another concern addresses the challenge of identifying a metric for human toxicity impacts that is aligned with the spatiotemporal resolution of present LCIA methodology, yet is adequate to indicate health impact potential.

CONCLUSIONS

Further research efforts are required based on our proposed set of recommendations for improving the characterization of human exposure and toxicity impacts in LCIA and other comparative assessment frameworks. https://doi.org/10.1289/EHP3871.

Global anthropogenic chemicals loads on the environment and the associated chemical footprint and planetary boundaries: a high-resolution regional study

Chemical pollution is a problem of global importance. Substances of main concern of chemists worldwide are heavy metals. Heavy metals, such as copper (Cu), nickel (Ni), lead (Pb), vanadium (V), etc., can pose a serious hazard to the environment and human health. Heavy metals are toxic even at very low concentrations. The methodology, described in this paper, considers a migration of chemical pollutants in the environment, in conjunction with the approach used in the Russian regulatory system. Estimations of Maximum Available Concentration overrun show that calculated and experimental data agree to a good extent, particularly for mercury contamination in freshwater bodies. In this study, due to the necessity to obtain data on heavy metals content in water, soil and air, based on available data on emissions, it was decided to use the USEtox model for the simulation of the redistribution of chemicals among such environmental compartments as urban air and air of settlements, fresh waters and coastal sea waters, ocean, agricultural soils and other soils. The USEtox model was chosen because it is available in the free access and its structure can be modified if needed (the model is executed in MS Excel), in addition there is a positive experience in using this model in the combination with Geographic Information Systems (GIS). The algorithm of the calculation of the mass transfer coefficients of chemicals in the hydrosphere and atmosphere, with the use of GIS, is described. This algorithm will provide large amounts of data on the intermedia transfer and transportation of chemical substances with water and air flows and their accumulation in various environmental compartments on a global (the planet Earth) and regional scale for the high-resolution of 0.5°×0.5° grid. In this paper, the case study for the Leningrad Region (the Russian Federation) is presented.

Multiscale Spatial Modeling of Human Exposure from Local Sources to Global Intake

Exposure studies, used in human health risk and impact assessments of chemicals, are largely performed locally or regionally. It is usually not known how global impacts resulting from exposure to point source emissions compare to local impacts. To address this problem, we introduce Pangea, an innovative multiscale, spatial multimedia fate and exposure assessment model. We study local to global population exposure associated with emissions from 126 point sources matching locations of waste-to-energy plants across France. Results for three chemicals with distinct physicochemical properties are expressed as the evolution of the population intake fraction through inhalation and ingestion as a function of the distance from sources. For substances with atmospheric half-lives longer than a week, less than 20% of the global population intake through inhalation (median of 126 emission scenarios) can occur within a 100 km radius from the source. This suggests that, by neglecting distant low-level exposure, local assessments might only account for fractions of global cumulative intakes. We also study ∼10 000 emission locations covering France more densely to determine per chemical and exposure route which locations minimize global intakes. Maps of global intake fractions associated with each emission location show clear patterns associated with population and agriculture production densities.