Human-toxicological effect and damage factors of carcinogenic and noncarcinogenic chemicals for life cycle impact assessment

Definition of a disability weight for human exposure to ionizing radiation and its application to the justification of medical exposure

Objectives

To establish a link between radiation dosimetry and disability-adjusted life-years (DALY) with the aim of quantifying the justification of medical exposures.

Methods

The health detriment, defined as lifetime loss of DALY at age of exposure to ionizing radiation for a US-European population was calculated. A simple model of the relationship was fitted to the results. Apart from in late life within the latency period for radiation-induced cancers, most of the relationship can be adequately fitted to a straight line of negative gradient. The gradient of this line corresponds to a loss of DALY per year following exposure to radiation and is therefore equivalent to a disability weight (DW) used in the calculation of DALY.

Results

Radiation dose-dependent DWs for radiation exposure to a US-European population are estimated as 0.020 DALY/yr/Sv for males and 0.022 DALY/yr/Sv for females.

Conclusions

By comparing a range of 66 radiological examinations in terms of the DWs of the disease or injury states with the DWs resulting from the associated radiological exposures, it is demonstrated graphically that the resulting benefit is far greater than the detriment in every case.

Advances in knowledge

The definition of a DW for ionizing radiation, proportional to effective dose as currently defined, can link radiation exposure to the existing large body of data on the DALY burden and DWs for a wide range of diseases and injuries, providing a means for the quantitative justification of the benefit-detriment balance of medical exposures.

Quantifying EDC Emissions from Consumer Products: A Novel Rapid Method and Its Application for Systematic Evaluation of Health Impacts

Endocrine-disrupting chemicals (EDCs) are widely used in consumer products and have been associated with adverse public health outcomes and significant economic costs. We developed a rapid chamber method for measuring EDC emissions from consumer products, significantly reducing the time to reach steady state from weeks or months to minutes or hours. Using this method, we quantified EDC emissions from a wide range of products, determined the emission-control parameters, and established their relationship with the EDC content (Wf) and physicochemical properties. By incorporating Wf data from consumer product databases and applying stochastic models, we systematically estimated emissions for 400 EDC-product combinations and assessed the associated exposure and disease burden for the U.S. population. Our results suggest that more than 60% of these combinations could result in carcinogenic disability-adjusted life years (DALYs) above the acceptable threshold. The overall disease burden caused by EDCs in consumer products can be substantial, with DALYs exceeding those associated with other pollutants, such as particulate matter, in a worst-case scenario. This study provides a valuable tool for prioritizing hazardous EDCs in consumer products, evaluating safer alternatives, and formulating effective intervention strategies, thereby supporting policymakers and manufacturers in making informed, sustainable decisions.

Two-Stage Machine Learning-Based Approach to Predict Points of Departure for Human Noncancer and Developmental/Reproductive Effects

Chemical points of departure (PODs) for critical health effects are crucial for evaluating and managing human health risks and impacts from exposure. However, PODs are unavailable for most chemicals in commerce due to a lack of in vivo toxicity data. We therefore developed a two-stage machine learning (ML) framework to predict human-equivalent PODs for oral exposure to organic chemicals based on chemical structure. Utilizing ML-based predictions for structural/physical/chemical/toxicological properties from OPERA 2.9 as features (Stage 1), ML models using random forest regression were trained with human-equivalent PODs derived from in vivo data sets for general noncancer effects (n = 1,791) and reproductive/developmental effects (n = 2,228), with robust cross-validation for feature selection and estimating generalization errors (Stage 2). These two-stage models accurately predicted PODs for both effect categories with cross-validation-based root-mean-squared errors less than an order of magnitude. We then applied one or both models to 34,046 chemicals expected to be in the environment, revealing several thousand chemicals of moderate concern and several hundred chemicals of high concern for health effects at estimated median population exposure levels. Further application can expand by orders of magnitude the coverage of organic chemicals that can be evaluated for their human health risks and impacts.

Probabilistic Reference and 10% Effect Concentrations for Characterizing Inhalation Non-cancer and Developmental/Reproductive Effects for 2,160 Substances

Chemicals assessment and management frameworks rely on regulatory toxicity values, which are based on points of departure (POD) identified following rigorous dose-response assessments. Yet, regulatory PODs and toxicity values for inhalation exposure (i.e., reference concentrations [RfCs]) are available for only ∼200 chemicals. To address this gap, we applied a workflow to determine surrogate inhalation route PODs and corresponding toxicity values, where regulatory assessments are lacking. We curated and selected inhalation in vivo data from the U.S. EPA's ToxValDB and adjusted reported effect values to chronic human equivalent benchmark concentrations (BMCh) following the WHO/IPCS framework. Using ToxValDB chemicals with existing PODs associated with regulatory toxicity values, we found that the 25th %-ile of a chemical's BMCh distribution (POD p 25 BMC h ) could serve as a suitable surrogate for regulatory PODs (Q2 ≥ 0.76, RSE ≤ 0.82 log10 units). We applied this approach to derive POD p 25 BMC h for 2,095 substances with general non-cancer toxicity effects and 638 substances with reproductive/developmental toxicity effects, yielding a total coverage of 2,160 substances. From these POD p 25 BMC h , we derived probabilistic RfCs and human population effect concentrations. With this work, we have expanded the number of chemicals with toxicity values available, thereby enabling a much broader coverage for inhalation risk and impact assessment.

Near-field exposures and human health impacts for organic chemicals in interior paints: A high-throughput screening

Interior paints contain organic chemicals that might be harmful to painters and building residents. This study aims to develop a high-throughput approach to screen near-field human exposures and health impacts related to organic chemicals in interior paints. We developed mass balance models for both water- and solvent-based paints, predicting emissions during wet and dry phases. We then screened exposures and risks, focusing on Sri Lanka where residential houses are frequently repainted. These models accurately predict paint drying time and indoor air concentrations of organic chemicals. Exposures of both painter and household resident were estimated for 65 organic chemicals in water-based and 26 in solvent-based paints, considering 12 solvents. Chemicals of concerns (CoCs) were identified, and maximum acceptable chemical contents (MACs) were calculated. Water-based paints generally pose lower health risks than solvent-based paints but might contain biocides of high concern. The total human health impact of one painting event on all household adults ranges from 1.5 × 10-3 to 2.1 × 10-2 DALYs for solvent-based paints, and from 4.1 × 10-4 to 9.5 × 10-3 DALYs for water-based paints. The present approach is a promising way to support the formulation of safer paint, and is integrated in the USEtox scientific consensus model for use in life cycle assessment, chemical substitution and risk screening.

Fe3O4@nitrogen-doped carbon core-double shell nanotubes as a novel and efficient nanosorbent for ultrasonic assisted dispersive magnetic solid phase extraction of heterocyclic pesticides from environmental soil and water samples

Fe3O4@nitrogen-doped carbon core-double shell nanotubes (Fe3O4@N-C C-DSNTs) were successfully synthesized and applied as a novel nanosorbent in ultrasonic assisted dispersive magnetic solid phase extraction (UA-DMSPE) of tribenuron-methyl, fenpyroximate, and iprodione. Subsequently, corona discharge ion mobility spectrometry (CD-IMS) was employed for the detection of the extracted analytes. Effective parameters on the extraction recovery percentage (ER%) were systematically investigated and optimized. Under optimal conditions, UA-DMSPE-CD-IMS demonstrated remarkable linearity in different ranges within 1.0 - 700 ng mL-1 with correlation coefficients exceeding 0.993, repeatability values below 6.9%, limits of detection ranging from 0.30 to 0.90 ng mL-1, high preconcentration factors (418 - 435), and ER% values (83 - 87%). The potential of the proposed method was further demonstrated by effectively determining the targeted pesticides in various environmental soil and water samples, exhibiting relative recoveries in the range 92.1 - 102%.

Harm from Residential Indoor Air Contaminants

This study presents a health-centered approach to quantify and compare the chronic harm caused by indoor air contaminants using disability-adjusted life-year (DALY). The aim is to understand the chronic harm caused by airborne contaminants in dwellings and identify the most harmful. Epidemiological and toxicological evidence of population morbidity and mortality is used to determine harm intensities, a metric of chronic harm per unit of contaminant concentration. Uncertainty is evaluated in the concentrations of 45 indoor air contaminants commonly found in dwellings. Chronic harm is estimated from the harm intensities and the concentrations. The most harmful contaminants in dwellings are PM2.5, PM10-2.5, NO2, formaldehyde, radon, and O3, accounting for over 99% of total median harm of 2200 DALYs/105 person/year. The chronic harm caused by all airborne contaminants in dwellings accounts for 7% of the total global burden from all diseases.

The burden of disease attributable to indoor air pollutants in China from 2000 to 2017

BACKGROUND

High-level exposure to indoor air pollutants (IAPs) and their corresponding adverse health effects have become a public concern in China in the past 10 years. However, neither national nor provincial level burden of disease attributable to multiple IAPs has been reported for China. This is the first study to estimate and rank the annual burden of disease and the financial costs attributable to targeted residential IAPs at the national and provincial level in China from 2000 to 2017.

METHODS

We first did a systematic review and meta-analysis of 117 articles from 37 231 articles identified in major databases, and obtained exposure-response relationships for the candidate IAPs. The exposure levels to these IAPs were then collected by another systematic review of 1864 articles selected from 52 351 articles. After the systematic review, ten IAPs with significant and robust exposure-response relationships and sufficient exposure data were finally targeted: PM2·5, nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide, radon, formaldehyde, benzene, toluene, and p-dichlorobenzene. The annual exposure levels in residences were then evaluated in all 31 provinces in mainland China continuously from 2000 to 2017, using the spatiotemporal Gaussian process regression model to analyse indoor originating IAPs, and the infiltration factor method to analyse outdoor originating IAPs. The disability-adjusted life-years (DALYs) attributable to the targeted IAPs were estimated at both national and provincial levels in China, using the population attributable fraction method. Financial costs were estimated by an adapted human capital approach.

FINDINGS

From 2000 to 2017, annual DALYs attributable to the ten IAPs in mainland China decreased from 4620 (95% CI 4070-5040) to 3700 (3210-4090) per 100 000. Nevertheless, in 2017, IAPs still ranked third among all risk factors, and their DALYs and financial costs accounted for 14·1% (95% CI 12·3-15·6) of total DALYs and 3·45% (3·01-3·82) of the gross domestic product. Specifically, the rank of ten targeted IAPs in order of their contribution to DALYs in 2017 was PM2·5, carbon monoxide, radon, benzene, nitrogen dioxide, ozone, sulphur dioxide, formaldehyde, toluene, and p-dichlorobenzene. The DALYs attributable to IAPs were 9·50% higher than those attributable to outdoor air pollution in 2017. For the leading IAP, PM2·5, the DALYs attributable to indoor origins are 18·3% higher than those of outdoor origins.

INTERPRETATION

DALYs attributed to IAPs in China have decreased by 20·0% over the past two decades. Even so, they are still much higher than those in the USA and European countries. This study can provide a basis for determining which IAPs to target in various indoor air quality standards and for estimating the health and economic benefits of various indoor air quality control approaches, which will help to reduce the adverse health effects of IAPs in China.

FUNDING

The National Key Research and Development Program of China and the National Natural Science Foundation of China.

Evaluating the Environmental Impact of Radiation Therapy Using Life Cycle Assessments: A Critical Review

Concurrent increases in global cancer burden and the climate crisis pose an unprecedented threat to public health and human well-being. Today, the health care sector greatly contributes to greenhouse gas emissions, with the future demand for health care services expected to rise. Life cycle assessment (LCA) is an internationally standardized tool that analyzes the inputs and outputs of products, processes, and systems to quantify associated environmental impacts. This critical review explains the use of LCA methodology and outlines its application to external beam radiation therapy (EBRT) with the aim of providing a robust methodology to quantify the environmental impact of radiation therapy care practices today. The steps of an LCA are outlined and explained as defined by the International Organization for Standardization (ISO 14040 and 14044) guidelines: (1) definition of the goal and scope of the LCA, (2) inventory analysis, (3) impact assessment, and (4) interpretation. The existing LCA framework and its methodology is described and applied to the field of radiation oncology. The goal and scope of its application to EBRT is the evaluation of the environmental impact of a single EBRT treatment course within a radiation oncology department. The methodology for data collection via mapping of the resources used (inputs) and the end-of-life processes (outputs) associated with EBRT is explained, with subsequent explanation of the LCA analysis steps. Finally, the importance of appropriate sensitivity analysis and the interpretations that can be drawn from LCA results are reviewed. This critical review of LCA protocol provides and evaluates a methodological framework to scientifically establish baseline environmental performance measurements within a health care setting and assists in identifying targets for emissions mitigation. Future LCAs in the field of radiation oncology and across medical specialties will be crucial in informing best practices for equitable and sustainable care in a changing climate.

Non-negligible health risks caused by inhalation exposure to aldehydes and ketones during food waste treatments in megacity Shanghai

Aldehydes and ketones in urban air continue to receive regulatory and scientific attention for their environmental prevalence and potential health hazard. However, current knowledge of the health risks and losses caused by these pollutants in food waste (FW) treatment processes is still limited, especially under long-term exposure. Here, we presented the first comprehensive assessment of chronic exposure to 21 aldehydes and ketones in urban FW-air environments (e.g., storage site, mechanical dewatering, and composting) by coupling substantial measured data (383 samples) with Monte Carlo-based probabilistic health risk and impact assessment models. The results showed that acetaldehyde, acetone, 2-butanone and cyclohexanone were consistently the predominant pollutants, although the significant differences in pollution profiles across treatment sites and seasons (Adonis test, P < 0.001). According to the risk assessment results, the estimated cancer risk (CR; mean range: 1.6 × 10^-5-1.12 × 10^-4) and non-cancer risk (NCR; mean range: 2.98-22.7) triggered by aldehydes and ketones were both unacceptable in most cases (CR: 37.8%-99.3%; NCR: 54.2%-99.8%), and even reached the limit of concern to CR (1 × 10^-4) in some exposure scenarios (6.18%-16.9%). Application of DALYs (disability adjusted life years) as a metric for predicting the damage suggested that exposure of workers to aldehydes and ketones over 20 years of working in FW-air environments could result in 0.02-0.14 DALYs per person. Acetaldehyde was the most harmful constituent of all targeted pollutants, which contributed to the vast majority of health risks (>88%) and losses (>90%). This study highlights aldehydes and ketones in FW treatments may be the critical pollutants to pose inhalation risks.

Probabilistic Points of Departure and Reference Doses for Characterizing Human Noncancer and Developmental/Reproductive Effects for 10,145 Chemicals

BACKGROUND

Regulatory toxicity values used to assess and manage chemical risks rely on the determination of the point of departure (POD) for a critical effect, which results from a comprehensive and systematic assessment of available toxicity studies. However, regulatory assessments are only available for a small fraction of chemicals.

OBJECTIVES

Using in vivo experimental animal data from the U.S. Environmental Protection Agency's Toxicity Value Database, we developed a semiautomated approach to determine surrogate oral route PODs, and corresponding toxicity values where regulatory assessments are unavailable.

METHODS

We developed a curated data set restricted to effect levels, exposure routes, study designs, and species relevant for deriving toxicity values. Effect levels were adjusted to chronic human equivalent benchmark doses (BMDh). We hypothesized that a quantile of the BMDh distribution could serve as a surrogate POD and determined the appropriate quantile by calibration to regulatory PODs. Finally, we characterized uncertainties around the surrogate PODs from intra- and interstudy variability and derived probabilistic toxicity values using a standardized workflow.

RESULTS

The BMDh distribution for each chemical was adequately fit by a lognormal distribution, and the 25th percentile best predicted the available regulatory PODs [R2≥0.78, residual standard error (RSE)≤0.53 log10 units]. We derived surrogate PODs for 10,145 chemicals from the curated data set, differentiating between general noncancer and reproductive/developmental effects, with typical uncertainties (at 95% confidence) of a factor of 10 and 12, respectively. From these PODs, probabilistic reference doses (1% incidence at 95% confidence), as well as human population effect doses (10% incidence), were derived.

DISCUSSION

In providing surrogate PODs calibrated to regulatory values and deriving corresponding toxicity values, we have substantially expanded the coverage of chemicals from 744 to 8,023 for general noncancer effects, and from 41 to 6,697 for reproductive/developmental effects. These results can be used across various risk assessment and risk management contexts, from hazardous site and life cycle impact assessments to chemical prioritization and substitution. https://doi.org/10.1289/EHP11524.

Assessing the environmental impacts and costs of biochar and monitored natural attenuation for groundwater heavily contaminated with volatile organic compounds

Although biochar (BC) and monitored natural attenuation (MNA) are regarded as green technologies for remediating volatile organic compounds (VOCs) contaminated groundwater, their life cycle environmental impacts and costs have not been systematically quantified. This work assessed the primary and secondary environmental impacts and the cost of three options for remediating the groundwater at a closed pesticide manufacturing plant site, which was contaminated by high levels of multiple VOCs and is undergoing MNA. The studied options include a combination of MNA and BC (MNA + BC), BC, and pump and treat (PT). The environmental impacts were examined through a Life Cycle Assessment (LCA) using the ReCiPe 2016 method. The costs were evaluated using a Life Cycle Cost (LCC) method created in the SimaPro. The LCA results show that the overall environmental impacts follow the sequence of PT > BC > MNA + BC, but MNA + BC shows evident primary impacts. The CO₂ eq emissions generated from PT are more than five times of MNA + BC or BC. The cement, electricity, and steel for construction, and the operation energy are the environmental hotspots in PT. In MNA + BC and BC, the electricity for feedstock pyrolysis is the environmental hotspot, while the use of BC by-products to generate heat and power has positive environmental credit that compensates other negative environmental burdens. Incorporating institutional controls, using renewable energy and recycled or alternative materials, and developing BC with superior adsorption capacity are recommended to optimize the remediation strategies. The LCC results show that PT renders the highest cost, with cement and electricity being the two most expensive items. Electricity is the dominant contributor to the costs of MNA + BC and BC, while the avoided heat and power generation can save the cost of other items. Overall, this study provides scientific support to develop and optimize green remediation solutions for VOCs contaminated groundwater.

Time-resolved dynamic disability adjusted life-years estimation

The quantification of how healthy the indoor air is, is a complex issue comprising of a large number of contaminants of various sources. The health implication of exposure to each of the contaminant deemed of importance can be expressed using Disability Adjusted Life Years (DALYs). The sum of all DALYs indicates how harmful the indoor air was during the investigated time-frame. This metric was originally developed by the World Bank and the WHO. In 2012, Logue et. al described two methods to estimate the DALYs related to exposure to contaminants in the indoor air based on the yearly mean exposure concentration of a population. The downside of these methods is that, when detailed exposure concentration profiles are available the method results in a loss of information. A novel method was developed to estimate DALYs originating from exposure to indoor pollutants that can be used for time-resolved exposure concentration data without this loss of information: Dynamic DALYs. The advantage of this method is that it can be calculated in real-time and for short or long periods of data. As such it can be used for pin-pointing problematic events in the exposure profile of a person and, as it can be calculated in real-time, makes it a candidate for use in automated optimization problems. The use of Dynamic DALYs is demonstrated for a simulation case-study of an occupied apartment. One continuously ventilated system (Dcont) and one smart ventilation system (Dsmart) are compared. Sources of typically indoor generated Volatile Organic Compounds (VOCs) were added and the related exposure profile and Dynamic DALY results of the working adult were analyzed. The results showcase detailed and more summative results with regards to health and energy use using the novel indicator. For Dcont and Dsmart the total Dynamic DALYs are 2.2 years and 8.6 years, respectively (population of 100 000, duration of 1 year), for the VOCs and sources considered in the analysis.

Indoor formaldehyde levels in residences, schools, and offices in China in the past 30 years: A systematic review

Exposure to formaldehyde causes a variety of adverse health outcomes, while the distributions of indoor formaldehyde in different building types are still not clear in China. In this study, based on the systematic review of previously published data and Monte Carlo simulation, we assessed geographical and temporal distributions of indoor formaldehyde concentrations in residences, schools, and offices across China. A total of 397 studies covered 34 provincial-level regions since 1986 were collected. The results showed that indoor formaldehyde concentrations in residences, schools, and offices in nationwide were decreasing over years due to the publishment of indoor air quality standards since 2002. During 2011 to 2015, the median concentrations of indoor formaldehyde in newly renovated residences, schools, and offices were 153 μg/m³ , 163 μg/m³ , and 94 μg/m³ , with an exceeding rate of 82%, 46%, and 91% considering a standard threshold of 100 μg/m³ at that time, while the exceeding rate was less than 5% for buildings that were renovated beyond one year. Our findings release the temporal trends and geographic distributions of indoor formaldehyde concentrations in residences, schools, and offices in China in the past 30 years, and provide basic data for the comprehensive evaluation of disease burden attributable to indoor formaldehyde exposure.

Approach toward In Vitro-Based Human Toxicity Effect Factors for the Life Cycle Impact Assessment of Inhaled Low-Solubility Particles

Today's scarcity of animal toxicological data for nanomaterials could be lifted by substituting in vivo data with in vitro data to calculate nanomaterials' effect factors (EF) for Life Cycle Assessment (LCA). Here, we present a step-by-step procedure to calculate in vitro-to-in vivo extrapolation factors to estimate human Benchmark Doses and subsequently in vitro-based EFs for several inhaled nonsoluble nanomaterials. Based on mouse data, the in vitro-based EF of TiO2 is between 2.76 · 10-4 and 1.10 · 10-3 cases/(m2/g·kg intake), depending on the aerodynamic size of the particle, which is in good agreement with in vivo-based EFs (1.51 · 10-4-5.6 · 10-2 cases/(m2/g·kg intake)). The EF for amorphous silica is in a similar range as for TiO2, but the result is less robust due to only few in vivo data available. The results based on rat data are very different, confirming the importance of selecting animal species representative of human responses. The discrepancy between in vivo and in vitro animal data in terms of availability and quality limits the coverage of further nanomaterials. Systematic testing on human and animal cells is needed to reduce the variability in toxicological response determined by the differences in experimental conditions, thus helping improve the predictivity of in vitro-to-in vivo extrapolation factors.

Improving pesticide fate models for a simple household food processing: considering multiple crop units

To understand the fate of pesticides in crops during household cooking processes and human health risks associated with the ingestion of pesticide-contaminated crops, we propose unit-variability-enhanced models, which are capable of evaluating the removal efficiency of pesticides in multiple crop units by soaking in water. The approach integrates the lognormal production model to reveal the modeling mechanics of internal contamination among two crop units in one soaking bowl. The simulated results for 197 pesticides indicate that pesticides with larger unit-to-unit variability factors (VF) at the residue levels and diffusivity rates in water (D_W) are more likely to cause internal contamination. Although internal contamination of pesticide residues between two crop units may occur, we find that the overall removal factor ([Formula: see text]) for two crop units is independent of the ratio of initial residue levels between the two crop units. Based on this discovery, we propose the unit-variability-based (UVB) rule to generalize the [Formula: see text] for an n-crop-unit system, where n crop units soak simultaneously in one container. In addition, we demonstrate that under the same consumable and recycling resources, the soaking of two crop units together in one container can yield a maximum mass removal of pesticides if the two units are randomly sampled. Although other factors, such as temperature and the nature of solutions in the cooking process, should be considered in future studies, our models suggest that this soaking method can be conveniently realized in households to reduce negative health effects.

Preschool children health impacts from indoor exposure to PM2.5 and metals

To better understand the relation between children health and indoor air quality, we measured the concentrations of fine particulate matter (PM_2.5) and 11 metals (arsenic, cadmium, chromium, copper, iron, manganese, nickel, lead, antimony, selenium, and zinc) from air samples taken during both winter and spring, and focused on urban and rural area kindergartens of the Upper Silesia Region, Poland, typified by the use of fossil fuels for power and heat purposes. We combined related inhalation intake estimates for children and health effects using separate dose-response approaches for PM_2.5 and metals. Results show that impacts on children from exposure to PM_2.5 was 7.5 min/yr, corresponding to 14 μDALY/yr (DALY: disability-adjusted life years) with 95% confidence interval (CI): 0.3-164 min/yr, which is approximately 10 times lower than cumulative impacts from exposure to the metal components in the PM_2.5 fraction of indoor air (median 76 min/yr; CI: 0.2-4.5 × 10³ min/yr). Highest metal-related health impacts were caused by exposure to hexavalent chromium. The average combined cancer and non-cancer effects for hexavalent chromium were 55 min/yr, corresponding to 104 μDALY/yr, with CI: 0.5 to 8.0 × 10⁴ min/yr. Health impacts on children varied by season and across urban and rural sites, both as functions of varying PM_2.5 metal compositions influenced by indoor and outdoor emission sources. Our study demonstrates the need to consider indoor environments for evaluating health impacts of children, and can assist decision makers to focus on relevant impact reduction and indoor air quality improvement.

Human Toxicological Impacts in Life Cycle Assessment of Circular Economy of the Built Environment: A Case Study of Denmark

The circular economy has become an important topic in the building industry, and life cycle assessment (LCA) is often used to quantify its benefits. Through chemical analysis, this article demonstrates that the current LCA is not yet well-adapted to assess the circular economy of building materials and components. It is shown that current inventory data and models are insufficient because they do not consider the uptake and emission of chemicals during use, the migration of chemicals within the value chain across the multiple phases in the circular economy, and because current characterization models lack a large fraction of the potentially emitted chemicals from said uptake and emission identified in the tested building material samples. Thus, it is shown that impacts relevant for LCA in the circular economy of buildings remain unaddressed because they are currently either omitted in the LCA that covers a limited number of impact indicators, or are ostensibly covered in the LCA covering a full set of indicators but missed due to inadequate characterization models. To ameliorate this, a definition of embedded toxicity and its relationship to the toxicological footprint is presented and a method for measurement is proposed, illustrating how assessing embedded toxicity can yield information for facilitating safe building-material reuse. Finally, a suggestion for the improvement of life cycle impact assessment methods is proposed.

Comparative Life Cycle Assessment of two advanced treatment steps for wastewater micropollutants: How to determine whole-system environmental benefits?

Advanced wastewater treatment (AWT) technologies are now considered to target urban micropollutants (MPs) before discharge into receiving water bodies and to comply with specific criteria for reuse. Extra energy and/or resources are necessary to achieve the elimination of MPs. Using the Life Cycle Assessment framework, this study assesses net environmental efficiencies for two AWTs (i) ozone systems (air-fed and pure oxygen-fed) and (ii) granular activated carbon filter. Sixty-five MPs with proven removal efficiency values and toxicity and/or ecotoxicity potentials were included in this study building on results from recent research. Consolidated Life Cycle Inventories with data quality and uncertainty characterization were produced with an emphasis on operational inputs. Results show that the direct water quality benefits obtained from AWT are outweighed by greater increases in indirect impacts from energy and resource demands. Future research should include water quality aspects not currently captured in life cycle impact assessment, such as endocrine disruption and whole-effluent toxicity, in order to assess the complete policy implications of MP removal strategies.

Quantifying Environmental and Economic Impacts of Highly Porous Activated Carbon from Lignocellulosic Biomass for High-Performance Supercapacitors

Activated carbons (AC) from lignocellulosic biomass feedstocks are used in a broad range of applications, especially for electrochemical devices such as supercapacitor electrodes. Limited studies of environmental and economic impacts for AC supercapacitor production have been conducted. Thus, this paper evaluated the environmental and economic impacts of AC produced from lignocellulosic biomass for energy-storage purposes. The life cycle assessment (LCA) was employed to quantify the potential environmental impacts associated with AC production via the proposed processes including feedstock establishment, harvest, transport, storage, and in-plant production. A techno-economic model was constructed to analyze the economic feasibility of AC production, which included the processes in the proposed technology, as well as the required facility installation and management. A base case, together with two alternative scenarios of KOH-reuse and steam processes for carbon activation, were evaluated for both environmental and economic impacts, while the uncertainty of the net present value (NPV) of the AC production was examined with seven economic indicators. Our results indicated that overall “in-plant production” process presented the highest environmental impacts. Normalized results of the life-cycle impact assessment showed that the AC production had environmental impacts mainly on the carcinogenics, ecotoxicity, and non-carcinogenics categories. We then further focused on life cycle analysis from raw biomass delivery to plant gate, the results showed that “feedstock establishment” had the most significant environmental impact, ranging from 50.3% to 85.2%. For an activated carbon plant producing 3000 kg AC per day in the base case, the capital cost would be USD 6.66 million, and annual operation cost was found to be USD 15.46 million. The required selling price (RSP) of AC was USD 16.79 per kg, with the discounted payback period (DPB) of 9.98 years. Alternative cases of KOH-reuse and steam processes had GHG emissions of 15.4 kg CO2 eq and 10.2 kg CO2 eq for every 1 kg of activated carbon, respectively. Monte Carlo simulation showed 49.96% of the probability for an investment to be profitable in activated carbon production from lignocellulosic biomass for supercapacitor electrodes.

A disease-specific screening-level modeling approach for assessing the cancer risks of pesticide mixtures

As humans are always exposed to multiple pesticides, it is necessary to conduct risk assessments for pesticide mixtures. Due to data limitations, in this study, we introduced a disease-specific screening-level modeling framework to simulate the cumulative cancer risk (CR) of carcinogenic pesticides, which was developed based on the lognormal dose-response (LDR) curve of chemicals with disease-specific modes of action (MOAs). The simulated results of a case study indicate that the cumulative CR can be at least two orders of magnitude higher than the simulated CRs of individual pesticides. The comparison between the LDR model and the linear extrapolation (or cancer slope factor, CSF) model indicates that the CSF model can greatly overestimate population cancer risks. In addition, we applied our model to evaluate current regulatory standards of carcinogenic pesticide mixtures, and the results indicate that current standards for the selected jurisdictions can control the cumulative cancer risks within the acceptable level. However, the CSF model suggests that all selected jurisdictions cannot protect population health against the carcinogenic pesticide mixture, which is due to the nature of the low-dose linear extrapolation that triggers an initial slope when the effect dose is close to zero. Thus, we concluded that although the MOAs of pesticides in human bodies must be evaluated in future studies, our disease-specific model can be a useful and practical tool for cancer risk assessment and regulatory management of pesticide mixtures.

Human Chemical Exposure from Background Emissions in the United States and the Implication for Quantifying Risks from Marginal Emission Increase

The linear dose-response relationship has long been assumed in assessments of health risk from an incremental chemical emission relative to background emissions. In this study, we systematically examine the relevancy of such an assumption with real-world data. We used the reported emission data, as background emissions, from the 2017 U.S. National Emission Inventory for 95 organic chemicals to estimate the central tendencies of exposures of the general U.S. population. Previously published nonlinear dose-response relationships for chemicals were used to estimate health risk from exposure. We also explored and identified four intervals of exposure in which the nonlinear dose-response relationship may be linearly approximated with fixed slopes. Predicted rates of exposure to these 95 chemicals are all within the lowest of the four intervals and associated with low health risk. The health risk may be overestimated if a slope on the dose-response relationship extrapolated from toxicological assays based on high response rates is used for a marginal increase in emission not substantially higher than background emissions. To improve the confidence of human health risk estimates for chemicals, future efforts should focus on deriving a more accurate dose-response relationship at lower response rates and interface it with exposure assessments.

Management of Asbestos Containing Materials: A Detailed LCA Comparison of Different Scenarios Comprising First Time Asbestos Characterization Factor Proposal

This work addresses the complex issue of asbestos containing materials (ACMs) management, by focusing on the scenario of six municipalities comprised in the Reggio Emilia province of Emilia Romagna Italian region. Particularly, the life cycle assessment (LCA) methodology was applied in order to assess in a quantitative and reliable manner the human toxicity as well as the ecotoxicity impacts associated with all of the different phases of ACMs management. The latter comprises mapping of ACMs, creation of a risk map for defining priority of intervention, encapsulation and removal of ACMs, as well as the as obtained asbestos containing waste (ACW) end of life. Particularly, a thermal inertisation treatment performed in a continuous industrial furnace was considered as the innovative end of life scenario to be compared with what actually was provided by the legislation of many countries worldwide, that is, the disposal of ACW in a controlled landfill for hazardous wastes. A characterization factor for asbestos fibers released both in outdoor air and in occupational setting was proposed for the first time and included in the USEtox 2.0 impact assessment method. This allowed us to reliably and quantitatively highlight that inertisation treatments should be the preferred solutions to be adopted by local and national authorities, especially if the obtained inert material finds application as secondary raw materials, thus contributing to a decrease in the environmental damage (limited to its toxicological contributions) to be associated with asbestos management.

Integrated Life Cycle Assessment for Sustainable Remediation of Contaminated Agricultural Soil in China

Agricultural land degradation is posing a serious threat to global food security. Restoration of the degraded land has traditionally been viewed as an inherently sustainable practice; however, restoration processes render consequential environmental impacts which could potentially exceed the benefit of restoration itself. In the present study, an integrated life cycle assessment analysis was conducted to evaluate life cycle primary, secondary, and tertiary impacts associated with the restoration of the contaminated agricultural land. The results demonstrated the importance of including spatially differentiated impacts associated with managing the land and growing crops. Comparing four risk management scenarios at a contaminated field in Southern China, it was found that the primary and secondary impacts followed the order of no action > chemical stabilization > phytoextraction > alternative planting. However, when tertiary impacts were taken into account, alternative planting rendered much higher footprint in comparison with phytoextraction and chemical stabilization, which provides evidence against an emerging notion held by some policy makers. Furthermore, assuming that the loss of the rice paddy field in Southern China is compensated by the deforested land in the Amazon rainforest, the total global environmental impact would far exceed that of no action, resulting in 687 ton CO₂-e ha^-1 of climate change impact. Overall, the present study provides new research findings to support more holistic policy making and also sheds lights on the future development of various restoration technologies.

Estimated Mortality and Morbidity Attributable to Smoke Plumes in the United States: Not Just a Western US Problem

As anthropogenic emissions continue to decline and emissions from landscape (wild, prescribed, and agricultural) fires increase across the coming century, the relative importance of landscape-fire smoke on air quality and health in the United States (US) will increase. Landscape fires are a large source of fine particulate matter (PM2.5), which has known negative impacts on human health. The seasonal and spatial distribution, particle composition, and co-emitted species in landscape-fire emissions are different from anthropogenic sources of PM2.5. The implications of landscape-fire emissions on the sub-national temporal and spatial distribution of health events and the relative health importance of specific pollutants within smoke are not well understood. We use a health impact assessment with observation-based smoke PM2.5 to determine the sub-national distribution of mortality and the sub-national and sub-annual distribution of asthma morbidity attributable to US smoke PM2.5 from 2006 to 2018. We estimate disability-adjusted life years (DALYs) for PM2.5 and 18 gas-phase hazardous air pollutants (HAPs) in smoke. Although the majority of large landscape fires occur in the western US, we find the majority of mortality (74%) and asthma morbidity (on average 75% across 2006-2018) attributable to smoke PM2.5 occurs outside the West, due to higher population density in the East. Across the US, smoke-attributable asthma morbidity predominantly occurs in spring and summer. The number of DALYs associated with smoke PM2.5 is approximately three orders of magnitude higher than DALYs associated with gas-phase smoke HAPs. Our results indicate awareness and mitigation of landscape-fire smoke exposure is important across the US.

Coherent Investigation on a Smart Kinetic Wooden Façade Based on Material Passport Concepts and Environmental Profile Inquiry

Wood is one of the most fully renewable building materials, so wood instead of non-renewable materials produced from organic energy sources significantly reduces the environmental impact. Construction products can be replenished at the end of their working life and their elements and components deconstructed in a closed-loop manner to act as a material for potential construction. Materials passports (MPs) are instruments for incorporating circular economy principles (CEP) into structures. Material passports (MPs) consider all the building’s life cycle (BLC) steps to ensure that it can be reused and transformed several times. The number of reuse times and the operating life of the commodity greatly influence the environmental effects incorporated. For a new generation of buildings, the developing of an elegant kinetic wooden façade has become a necessity. It represents a multidisciplinary region with different climatic, fiscal, constructional materials, equipment, and programs, and ecology-influencing design processes and decisions. Based on an overview of the material’s environmental profile (MEP) and material passport (MP) definition in the design phase, this article attempts to establish and formulate an analytical analysis of the wood selection process used to produce a kinetic façade. The paper will analyze the importance of environmentally sustainable construction and a harmonious architectural environment to reduce harmful human intervention on the environment. It will examine the use of wooden panels on buildings’ façades as one solution to building impact on the environment. It will show the features of the formation of the wooden exterior of the building. It will also examine modern architecture that enters into a dialogue with the environment, giving unique flexibility to adapt a building. The study finds that new buildings can be easily created today. The concept of building materials passport and the environmental selection of the kinetic wooden façade can be incorporated into the building design process. This will improve the economic and environmental impact of the building on human life.

Exposure and Toxicity Characterization of Chemical Emissions and Chemicals in Products: Global Recommendations and Implementation in USEtox

PURPOSE

Reducing chemical pressure on human and environmental health is an integral part of the global sustainability agenda. Guidelines for deriving globally applicable, life cycle based indicators are required to consistently quantify toxicity impacts from chemical emissions as well as from chemicals in consumer products. In response, we elaborate the methodological framework and present recommendations for advancing near-field/far-field exposure and toxicity characterization, and for implementing these recommendations in the scientific consensus model USEtox.

METHODS

An expert taskforce was convened by the Life Cycle Initiative hosted by UN Environment to expand existing guidance for evaluating human toxicity impacts from exposure to chemical substances. This taskforce evaluated advances since the original release of USEtox. Based on these advances, the taskforce identified two major aspects that required refinement, namely integrating near-field and far-field exposure and improving human dose-response modeling. Dedicated efforts have led to a set of recommendations to address these aspects in an update of USEtox, while ensuring consistency with the boundary conditions for characterizing life cycle toxicity impacts and being aligned with recommendations from agencies that regulate chemical exposure. The proposed framework was finally tested in an illustrative rice production and consumption case study.

RESULTS AND DISCUSSION

On the exposure side, a matrix system is proposed and recommended to integrate far-field exposure from environmental emissions with near-field exposure from chemicals in various consumer product types. Consumer exposure is addressed via submodels for each product type to account for product characteristics and exposure settings. Case study results illustrate that product-use related exposure dominates overall life cycle exposure. On the effect side, a probabilistic dose-response approach combined with a decision tree for identifying reliable points of departure is proposed for non-cancer effects, following recent guidance from the World Health Organization. This approach allows for explicitly considering both uncertainty and human variability in effect factors. Factors reflecting disease severity are proposed to distinguish cancer from non-cancer effects, and within the latter discriminate reproductive/developmental and other non-cancer effects. All proposed aspects have been consistently implemented into the original USEtox framework.

CONCLUSIONS

The recommended methodological advancements address several key limitations in earlier approaches. Next steps are to test the new characterization framework in additional case studies and to close remaining research gaps. Our framework is applicable for evaluating chemical emissions and product-related exposure in life cycle assessment, chemical alternatives assessment and chemical substitution, consumer exposure and risk screening, and high-throughput chemical prioritization.

High Throughput Risk and Impact Screening of Chemicals in Consumer Products

The ubiquitous presence of more than 80,000 chemicals in thousands of consumer products used on a daily basis stresses the need for screening a broader set of chemicals than the traditional well-studied suspect chemicals. This high-throughput screening combines stochastic chemical-product usage with mass balance-based exposure models and toxicity data to prioritize risks associated with household products. We first characterize product usage using the stochastic SHEDS-HT model and chemical content in common household products from the CPDat database, the chemical amounts applied daily varying over more than six orders of magnitude, from mg to kg. We then estimate multi-pathways near- and far-field exposures for 5,500 chemical-product combinations, applying an extended USEtox model to calculate product intake fractions ranging from 0.001 to ∼1, and exposure doses varying over more than nine orders of magnitude. Combining exposure doses with chemical-specific dose-responses and reference doses shows that risks can be substantial for multiple home maintenance products, such as paints or paint strippers, for some home-applied pesticides, leave-on personal care products, and cleaning products. Sixty percent of the chemical-product combinations have hazard quotients exceeding 1, and 9% of the combinations have lifetime cancer risks exceeding 10^-4 . Population-level impacts of household products ingredients can be substantial, representing 5 to 100 minutes of healthy life lost per day, with users' exposures up to 10³ minutes per day. To address this issue, present mass balance-based models are already able to provide exposure estimates for both users and populations. This screening study shows large variations of up to 10 orders of magnitude in impact across both chemicals and product combinations, demonstrating that prioritization based on hazard only is not acceptable, since it would neglect orders of magnitude variations in both product usage and exposure that need to be quantified. To address this, the USEtox suite of mass balance-based models is already able to provide exposure estimates for thousands of product-chemical combinations for both users and populations. The present study calls for more scrutiny of most impacting chemical-product combinations, fully ensuring from a regulatory perspective consumer product safety for high-end users and using protective measures for users.

Integrating endocrine-related health effects into comparative human toxicity characterization

Endocrine-disrupting chemicals have the ability to interfere with and alter functions of the hormone system, leading to adverse effects on reproduction, growth and development. Despite growing concerns over their now ubiquitous presence in the environment, endocrine-related human health effects remain largely outside of comparative human toxicity characterization frameworks as applied for example in life cycle impact assessments. In this paper, we propose a new methodological framework to consistently integrate endocrine-related health effects into comparative human toxicity characterization. We present two quantitative and operational approaches for extrapolating towards a common point of departure from both in vivo and dosimetry-adjusted in vitro endocrine-related effect data and deriving effect factors as well as corresponding characterization factors for endocrine-active/endocrine-disrupting chemicals. Following the proposed approaches, we calculated effect factors for 323 chemicals, reflecting their endocrine potency, and related characterization factors for 157 chemicals, expressing their relative endocrine-related human toxicity potential. Developed effect and characterization factors are ready for use in the context of chemical prioritization and substitution as well as life cycle impact assessment and other comparative assessment frameworks. Endocrine-related effect factors were found comparable to existing effect factors for cancer and non-cancer effects, indicating that (1) the chemicals' endocrine potency is not necessarily higher or lower than other effect potencies and (2) using dosimetry-adjusted effect data to derive effect factors does not consistently overestimate the effect of potential endocrine disruptors. Calculated characterization factors span over 8-11 orders of magnitude for different substances and emission compartments and are dominated by the range in endocrine potencies.

Life cycle assessment of municipal waste management options

To date, landfilling remains the most common waste management practice in Greece in spite of enforced regulations aiming at increasing recycling, pre-selection of waste and energy and material recovery. In this study, selected alternative scenarios aiming at minimizing the unused material fraction to be disposed of in landfills are analyzed, using the life cycle assessment methodology. The methodology was applied in the case of municipal solid waste (MSW) management in Athens and Thessaloniki, with a special focus on energy and material balance, including potential global and local scale airborne emissions. Results are given in the form of indices efficiency, effectiveness, environmental and public health impacts. Material flow accounting, gross energy requirement, emergy intensity, emission and release intensity and morbidity or mortality indicators have been used to support the comparative assessment. However, not all options are equally benign to the local environment and to the health of the local population, since both the former and the latter are still affected by non-negligible local emissions. With regard to public health impacts, adverse effects on respiratory health, congenital malformations, low birth weight and cancer incidence were estimated. A significant and not intuitive result is the fact that life cycle analysis produces different conclusions than a simple environmental impact assessment based only on estimated or measured emissions. Taking into account the overall life cycle of both the waste streams and of the technological systems and facilities envisaged alters the relative attractiveness of the solutions considered.

An equivalency iterative algorithm for cancer risk assessment of chemical mixtures with additive effects

To better estimate cumulative cancer risks and avoid the overestimated risk from the linear extrapolation, an equivalency iterative algorithm associated with a carcinogenesis hypothesis was introduced for a mixture of chemicals with the same mode of action (MOA). A lognormal dose-response function was applied for carcinogenic chemicals. Under some circumstances, the repetitive random iterative algorithm could be transformed into the nonrepetitive one. It was also demonstrated that the equivalent value for a lognormal-based equivalency iterative algorithm with the same shape parameter was independent of the operation order. Based on the theorems of the algorithm and Plackett and Hewlett's minimum effective dose assumption, the sum of toxicity-weighted dose for a mixture of chemicals was mathematically derived. Compared to the estimation of risk by the linear extrapolation method (e.g., cancer slope factors), the equivalency iterative algorithm for lognormal functions can avoid overestimated risk significantly, which can help better estimate the cumulative cancer risk for a mixture of chemicals with the same MOA.

Comparison of Different Monetization Methods in LCA: A Review

Different LCA methods based on monetization of environmental impacts are available. Therefore, relevant monetization methods, namely Ecovalue12, Stepwise2006, LIME3, Ecotax, EVR, EPS, the Environmental Prices Handbook, Trucost and the MMG-Method were compared quantitatively and qualitatively, yielding results for 18 impact categories. Monetary factors for the same impact category range mostly between two orders of magnitude for the assessed methods, with some exceptions (e.g., mineral resources with five orders of magnitude). Among the qualitative criteria, per capita income, and thus the geographical reference, has the biggest influence on the obtained monetary factors. When the monetization methods were applied to the domestic yearly environmental damages of an average EU citizen, their monetary values ranged between 7941.13 €/capita (Ecotax) and 224.06 €/capita (LIME3). The prioritization of impact categories varies: Stepwise and Ecovalue assign over 50% of the per capita damages to climate change, while EPS and LIME3 assign around 50% to mineral and fossil resource use. Choices regarding the geographical reference, the Areas of Protection included, cost perspectives and the approach to discounting strongly affect the magnitude of the monetary factors. Therefore, practitioners should choose monetization methods with care and potentially apply varying methods to assess the robustness of their results.

Multi-Walled Carbon Nanotubes for Magnetic Solid-Phase Extraction of Six Heterocyclic Pesticides in Environmental Water Samples Followed by HPLC-DAD Determination

Magnetic multi-walled carbon nanotubes were prepared as magnetic solid-phase extraction (MSPE) adsorbent for the enrichment of six heterocyclic pesticides in environmental water samples, including imidacloprid, triadimefon, fipronil, flusilazole, chlorfenapyr and fenpyroximate. Then six heterocyclic pesticides were separated and determined by high-performance liquid chromatography-diode-array detector (HPLC-DAD). Major factors influencing MSPE efficiency, including the dose of mag-multi-walled carbon nanotubes (mag-MWCNTs), extraction time, solution pH, salt concentration, type and volume of eluent and desorption time were investigated. Under the optimized conditions, the enrichment factor of the method reached to 250. The linearity was achieved within 0.05–10.0 μg/L for imidacloprid and chlorfenapyr, 0.10–10.0 μg/L for fipronil, flusilazole, triadimefon and fenpyroximate. Limits of detection were in the range of 0.01–0.03 μg/L. Good precision at three spiked levels were 1.1–11.2% (intra-day) and 1.7–11.0% (inter-day) with relative standard deviation of peak area, respectively. The developed method was utilized to analyze tap water, river water and reservoir water samples and recoveries at three spiked concentration levels ranged from 72.2% to 107.5%. The method was proved to be a convenient, rapid and practical method for sensitive determination of heterocyclic pesticides.

Detection and risk assessments of multi-pesticides in 1771 cultivated herbal medicines by LC/MS-MS and GC/MS-MS

Focus on the safety of herbal medicines has mainly been directed towards the presence of intrinsic toxicity, as found in the cases of renal and hepatic dysfunction caused by aristolochic acids. However, contamination from extrinsic hazards may impart an even greater reduction in their safety and efficacy. This study reveals that pesticides were present in the majority (88%) of a comprehensive cross-section (n = 1771) of herbal medicine samples. Alarmingly, more than half (59%) contained pesticides over the European Pharmacopoeia (EP) limit, and 43% of them contained 35 varieties of banned, extremely toxic pesticides, eight of which were detected at levels over 500 times higher than the default Maximum Residue Limit (MRL). DDTs, carbofuran, and mevinphos were confirmed as being among the most risk-inducing pesticides by three different risk assessment methods, reported to produce carcinogenic, genotoxic, reproductive, and developmental effects, in addition to carrying nephrotoxicity and hepatotoxicity. In light of these findings, and withstanding that extrinsic hazards can be controlled unlike intrinsic toxicity, the authors here strongly recommend the application of herbal medicine quality-control measures and solutions to safeguard against a neglected but certainly potentially serious health risk posed to the majority of the global population that consumes herbal medicines.

PBCLM: A top-down causal modeling framework for soil standards and global sustainable agriculture

To help countries worldwide regulate agricultural soil standards for organic contaminants, this study developed the pastoral-based chemical lifecycle management (PBCLM) modeling framework, which comprehensively models the bottom-up causation of the chemicals' lifecycle at each level of the cattle industry and delivers top-down regulatory strategies. The lifecycle models for a total of 308 hydrophobic organic contaminants were constructed. The results indicated that the octanol-water partitioning coefficient (log K_OW) values had the greater impact on the unit-legal-limit-based concentrations for contaminants at the producer level (i.e., grass) or higher. In addition, the analysis of the weather variables indicated that pastoral farming in warmer and drier places might lead to the bioaccumulation of more contaminants. By comparing the reference legal limits that were derived by the PBCLM, current soil standards might not be effective in protecting human health or harmonizing downstream food regulations. The PBCLM can help regulatory agencies better promulgate soil regulations to ensure sustainable agriculture.

Risk-based principles and incompleteness theorems for linear dose-response extrapolation for carcinogenic chemicals

To conduct better health risk assessments, this study introduced two risk-based principles and a series of line-lognormal-intersection theorems that helped derive the safe ranges of the cancer slope factors (CSFs) for 708 carcinogenic chemicals. The extrapolated linear dose-response relationships presented in this study can ensure safety with respect to both static and dose-based instantaneous risks compared to the lognormal dose-response model. The theorems proved that the maximum static and dose-based hazard risk ratios of a lognormal curve and a linear model are independent of a chemical's toxicity (the effect dose that corresponds to a 50% response, or ED₅₀), where the selected linear extrapolation (m value) and the individual variability (σ) of the responses to carcinogenic chemicals are two determining factors. The theorems also indicated that individual variability determines the range of m if the acceptable risk ratios were regulated. When σ was 1.36 (i.e., the 50th percentile of the individual variability's lognormal distribution), the safe range of m was derived as [11.22, 21.46] (i.e., from ED_11.22 to ED_21.46); if the 95th percentile of the σ lognormal distribution was used, the safe range of m was [1.13, 4.57] (i.e., from ED_1.13 to ED_4.57). This study also showed that for a relatively homogenous population (i.e., σ is relatively small) that has similar characteristics, the linear dose-response extrapolation method might not be completely effective due to the shape shift of the lognormal curve that draws the static risk of the extrapolated linear model away from the lognormal model.

Quantifying the handprint-Footprint balance into a single score: The example of pharmaceuticals

Life Cycle Assessment typically focuses on the footprint of products and services, expressed on three Areas of Protection (AoP): Human Health, Ecosystems and Resources. While the handprint is often expressed qualitatively, quantified handprints have recently been compared directly to the footprint concerning one AoP: Human Health. We propose to take this one step further by simultaneously comparing the quantified handprint and footprint on all AoPs through normalization and weighting of the results towards a single score. We discuss two example cases of a pharmaceutical treatment: mebendazole to treat soil-transmitted helminthiases and paliperidone palmitate to treat schizophrenia. Each time, treatment is compared to 'no treatment'. The footprint of health care is compared to the handprint of improved patient health. The handprint and footprint were normalized separately. To include sensitivity in the normalization step we applied four sets of external normalization factors for both handprint (Global Burden of Disease) and footprint (ReCiPe and PROSUITE). At the weighting step we applied 26 sets of panel weighting factors from three sources. We propose the Relative Sustainability Benefit Rate (RSBR) as a new metric to quantify the relative difference in combined handprint and footprint single score between two alternatives. When only considering the footprint, the first case study is associated with an increased single score burden of treatment compared to 'no treatment', while in the second case study treatment reduces the single score burden by 41.1% compared to 'no treatment'. Also including the handprint provided new insights for the first case study, now showing a decrease of 56.4% in single score burden for treatment compared to 'no treatment'. For the second case study the reduction of single score burden was confirmed as the handprint burden was also decreased because of treatment by 9.9%, reinforcing the findings.

Assessing Health Impacts of Conventional Centralized and Emerging Resource Recovery-Oriented Decentralized Water Systems

Energy shortage and climate change call for sustainable water and wastewater infrastructure capable of simultaneously recovering energy, mitigating greenhouse gas emissions, and protecting public health. Although energy and greenhouse gas emissions of water and wastewater infrastructure are extensively studied, the human health impacts of innovative infrastructure designed under the principles of decentralization and resource recovery are not fully understood. In order to fill this knowledge gap, this study assesses and compares the health impacts of three representative systems by integrating life cycle and microbial risk assessment approaches. This study found that the decentralized system options, such as on-site septic tank and composting or urine diverting toilets, presented much lower life cycle cancer and noncancer impacts than the centralized system. The microbial risks of decentralized systems options were also lower than those of the centralized system. Moreover, life cycle cancer and noncancer impacts contributed to approximately 95% of total health impacts, while microbial risks were associated with the remaining 5%. Additionally, the variability and sensitivity assessment indicated that reducing energy use of wastewater treatment and water distribution is effective in mitigating total health damages of the centralized system, while reducing energy use of water treatment is effective in mitigating total health damages of the decentralized systems.

Human Health Benefits from Fish Consumption vs. Risks from Inhalation Exposures Associated with Contaminated Sediment Remediation: Dredging of the Hudson River

BACKGROUND

Billions of dollars are spent on environmental dredging (ED) to remediate contaminated sediments, with one goal being reduced human health risks. However, ED may increase health risks in unanticipated ways, thus potentially reducing net benefits.

OBJECTIVES

To assess the ways that ED may increase health risks in unanticipated ways, thus potentially reducing net benefits, we quantitatively assessed a subset of population health benefits and risks of ED, using the 2009-2015 remediation of the Hudson River Polychlorinated Biphenyls (PCBs) Superfund Site as a case study. Three remediation scenarios were evaluated: No Action (NA), Source Control (SC), and ED.

METHODS

We quantified health benefits for each scenario from reduced PCB levels in Hudson River fish, and health risks from ED operations due to increased inhalation exposures to PCBs and fine particulate matter (PM 2.5 ), using disability-adjusted life years (DALYs) as a common metric. Occupational health risks were also considered in a separate sensitivity analysis. Estimates of population-level benefits and risks included Monte Carlo simulation-based uncertainty analysis.

RESULTS

Under NA, fish consumption would result in an estimated health burden of 112 DALYs, and ED would lead to a reduction of 15 DALYs in excess of SC. ED operations were estimated to induce a total burden of 33 DALYs, dominated by PM 2.5 impacts from rail transport emissions (32 DALYs). Including uncertainty, the net health benefit of ED ranged from - 138 to + 1,326 avoided DALYs (90% confidence), with a median of - 11 avoided DALYs.

CONCLUSIONS

For the considered impacts, ED in the Hudson River might not have led to an overall net positive human health impact. The benefits and risks of ED, however, have different degrees of uncertainty and involve different populations. Reducing long-distance transport of dredged sediment is a priority. This comparative approach could be used prospectively to better determine trade-offs involved in different remediation scenarios and to improve remediation design to maximize benefits while minimizing risks. https://doi.org/10.1289/EHP5034.

Human health benefit and burden of the schizophrenia health care pathway in Belgium: paliperidone palmitate long-acting injections

Background

Environmental impact assessments of pharmaceuticals typically consider only a part of the pharmaceutical supply chain, e.g. tablet formulation. While the environmental impact can be expressed in environmental Human Health burden due to resource use and emissions, the Human Health benefit of the pharmaceutical treatment of patients is currently not simultaneously taken into account. The study aims include a cradle-to-grave assessment of all Human Health impacts of the production, administration and disposal of two antipsychotics for the treatment of schizophrenia. This is complemented with the environmental impact of health care providers such as hospitals. The aim is to holistically quantify to what extent the environmental Human Health burden compares to the Human Health benefit associated with the treatment.

Methods

We applied an overall framework which included Life Cycle Assessment to model the environmental Human Health impacts of the pharmaceutical supply chain, administration and disposal of the drug and health care providers. To model the patient benefit, this was complemented with a Markov model with a 1-year time horizon. Three patient groups were modeled: medicine coverage of paliperidone palmitate for either one month (PP1M) or three months (PP3M) at a time, and compared to Treatment Interruption (TI) as a control group. Outcomes were quantified using Years of Life Lost (YLL), Years Lived with Disability (YLD) and Disability-Adjusted Life Years (DALY).

Results

The main environmental impacts were visits to the psychiatrist and psychiatric hospitals. The pharmaceutical supply chain had a limited impact. For 1000 patients for 1 year, PP1M and PP3M respectively avoided 0.38 and 0.49 environmental DALYs compared to TI. PP1M and PP3M further avoided 45.60 and 57.87 YLL and 23.31 and 29.91 YLD compared to TI. The main outcome was the sum of environmental DALYs, YLL and YLD, in which PP1M and PP3M respectively avoided 69.29 and 88.26 DALYs. Alternative analysis of Quality-Adjusted Life Years confirmed the results.

Conclusions

The overall environmental burden was lower for PP1M and PP3M treatment than Treatment Interruption because patients are kept more stable, which reduces the environmental burden due to hospitals. Moreover, the Human Health burden was outweighed by the Human Health benefit.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-4247-2) contains supplementary material, which is available to authorized users.

Integrating exposure to chemicals in building materials during use stage

PURPOSE

There do not currently exist scientifically defensible ways to consistently characterize the human exposures (via various pathways) to near-field chemical emissions and associated health impacts during the use stage of building materials. The present paper thus intends to provide a roadmap which summarizes the current status and guides future development for integrating into LCA the chemical exposures and health impacts on various users of building materials, with a focus on building occupants.

METHODS

We first review potential human health impacts associated with the substances in building materials and the methods used to mitigate these impacts, also identifying several of the most important online data resources. A brief overview of the necessary steps for characterizing use stage chemical exposures and health impacts for building materials is then provided. Finally, we propose a systematic approach to integrate the use stage exposures and health impacts into building material LCA and describe its components, and then present a case study illustrating the application of the proposed approach to two representative chemicals: formaldehyde and methylene diphenyl diisocyanate (MDI) in particleboard products.

RESULTS AND DISCUSSION

Our proposed approach builds on the coupled near-field and far-field framework proposed by Fantke et al. (Environ Int 94:508-518, 2016), which is based on the product intake fraction (PiF) metric proposed by Jolliet et al. (Environ Sci Technol 49:8924-8931, 2015), The proposed approach consists of three major components: characterization of product usage and chemical content, human exposures, and toxicity, for which available methods and data sources are reviewed and research gaps are identified. The case study illustrates the difference in dominant exposure pathways between formaldehyde and MDI and also highlights the impact of timing and use duration (e.g., the initial 50 days of the use stage vs. the remaining 15 years) on the exposures and health impacts for the building occupants.

CONCLUSIONS

The proposed approach thus provides the methodological basis for integrating into LCA the human health impacts associated with chemical exposures during the use stage of building materials. Data and modeling gaps which currently prohibit the application of the proposed systematic approach are discussed, including the need for chemical composition data, exposure models, and toxicity data. Research areas that are not currently focused on are also discussed, such as worker exposures and complex materials. Finally, future directions for integrating the use stage impacts of building materials into decision making in a tiered approach are discussed.

Life cycle assessment of advanced wastewater treatment processes: Involving 126 pharmaceuticals and personal care products in life cycle inventory

Continuous exposure to pharmaceuticals and personal care products (PPCPs) is a critical concern given potential toxicity impacts on aquatic environments and human health, although concentrations of PPCPs in the environment are low. While several studies have focused on the fate and toxicity of organic micropollutants in wastewater, the environmental impacts of life cycle assessment induced by these organic micropollutants in advanced wastewater treatment processes are still unknown. To address this need, an environmental evaluation of three representative advanced wastewater treatment processes (ozonation, granular activated carbon adsorption and reverse osmosis) involving PPCPs removal was conducted using life cycle assessment and USEtox model in this study. Although a large amount of PPCPs can be eliminated during conventional waste highest characterization factors for freshwater toxicity, while 17α-ethinylestradiol, sertraline, and 17β-estradiol had the highest human toxicity characterization factors. From the perspective of LCA, reverse osmosis appeared to have the greatest environmental burden due to the high energy and material consumption during the treatment process. After involving 126 PPCPs in life cycle inventory, the ecotoxicity impact results were increased significantly in three advanced wastewater treatment processes. The contribution of effluent was improved in toxicity impact category, accounting more than 25% for the three processes. The effluent (including PPCPs) as the key factor was next only to electricity and chemicals in eutrophication, ecotoxicity and human toxicity impacts category particularly. Therefore, PPCPs should not be ignored in life cycle assessment of advanced wastewater treatment processes, although they are not typically monitored in wastewater. These results are valuable for conducting a comprehensive environmental evaluation of advanced wastewater treatment processes considering micro-pollutants removal. The identified PPCPs with high freshwater and human toxicity can be considered as the priority control index of organic micropollutants for wastewater treatment plants.

Confronting variability with uncertainty in the ecotoxicological impact assessment of down-the-drain products

The use of down-the-drain products and the resultant release of chemicals may lead to pressures on the freshwater environment. Ecotoxicological impact assessment is a commonly used approach to assess chemical products but is still influenced by several uncertainty and variability sources. As a result, the robustness and reliability of such assessments can be questioned. A comprehensive and systematic assessment of these sources is, therefore, needed to increase their utility and credibility. In this study, we present a method to systematically analyse the uncertainty and variability of the potential ecotoxicological impact (PEI) of chemicals using a portfolio of 54 shampoo products. We separately quantified the influence of the statistical uncertainty in the prediction of physicochemical properties and freshwater toxicity as predicted from Quantitative Structure-Property Relationships (QSPRs) and Quantitative Structure-Activity Relationships (QSARs) respectively, and of various sources of spatial and technological variability as well as variability in consumer habits via 2D Monte Carlo simulations. Overall, the variation in the PEIs of shampoo use was mainly the result of uncertainty due to the use of toxicity data from three species only. All uncertainty sources combined resulted in PEIs ranging on average over seven orders of magnitude (ratio of the 90th to the 10th percentile) so that an absolute quantification of the ecological risk would not be meaningful. In comparison, variation in shampoo composition was the most influential source of variability, although less than compared to uncertainty, leading to PEIs ranging over three orders of magnitude. Increasing the number of toxicity data by increasing the number of species, either through additional measurements or ecotoxicological modelling (e.g. using Interspecies Correlation Equations), should get priority to improve the reliability of PEIs. These conclusions are not limited to shampoos but are applicable more generally to the down-the-drain products since they all have similar data limitations and associated uncertainties relating to the availability of ecotoxicity data and variability in consumer habits and use.

Burden of disease for workers attributable to exposure through inhalation of PPAHs in RSPM from cooking fumes

Polycyclic aromatic hydrocarbons (PAHs), some of which are classified as possible carcinogens (WHO), have been detected in cooking fumes in considerable amounts. Distribution of 24 PAHs on varying particle sizes was analyzed in cooking emission. Analysis of cooking fumes from vegetarian and non-vegetarian food was carried out separately in the kitchen of a hostel mess in IIT Kanpur during November 2012 and February 2013. Respirable suspended particulate matter (RSPM) and particle-bound polycyclic aromatic hydrocarbons (PPAHs) showed a similar sequence regarding concentration observed in vegetarian and non-vegetarian food. PAHs with carcinogenic potential was detected and quantified mostly in the fine particles. Total PAH concentrations in the fine and ultrafine ranges together accounted for > 90% of the total carcinogenic PAHs, highlighting them as primary carriers of PAHs rather than coarser particles. Benzo [a] pyrene (B [a]P) levels contribute > 70% to total carcinogenic potential and > 60%, to mutagenic potential, respectively. The total toxicity impact on the workers due to the PAHs emitted from cooking fumes was 3.374 × 10^-10 DALYs, with B [a] P contributing the most (> 70%) despite its low concentration. Exposure to cooking fumes especially for people involved in this activity on a daily basis (chefs, hostel mess workers, among others) raises health concerns. An extensive examination of impacts due to exposure to emissions in both particle and gas phase on a long-term basis is required.

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.

A Bayesian generalized log-normal model to dynamically evaluate the distribution of pesticide residues in soil associated with population health risks

Exploring better models for evaluating the distribution of pesticide residues in soil and sediment is necessary to assess and avoid population health risk. Frequentist philosophy and probability are widely used in many studies to apply a log-normal distribution associated with the maximum likelihood estimation, which assumes fixed parameters and relies on a large sample size for long-run frequency. However, frequentist probability might not be suitable for analyzing pesticide residue distribution, whose parameters are affected by many complex factors and should be treated as unfixed. This study aimed to implement a Bayesian generalized log-normal (GLN) model to better understand the distribution of pesticide residues in soil and quantify population risks. The Bayesian GLN model, including location, scale, and shape parameters, was applied for the first time to dynamically evaluate pesticide residue distribution in soil and sediments. In addition, a comprehensive human health risk assessment of exposure to lindane via soil was conducted using the lifetime cancer risk for carcinogenic effect, margin of exposure for non-carcinogenic effect, and disability-adjusted life year for health damage. The Bayesian posterior analysis results indicated that the distribution of the concentration of some pesticide was better fitted to a log-Laplace (e.g., the mode value of shape parameter for lindane is 1.079) or showed mixtures of distributions within the family of log-normal distributions (e.g., the mode value of shape parameter for p,p'-DDE is 2.395), which can better explain the long-tail phenomenon of pesticide residue distribution and dynamically evaluate distribution models. For lindane, the 95% uncertainty bounds on the 95th percentile computed from 95% highest probability density regions (credible intervals) of three parameters by using the Bayesian p-box method were [2.063, 1558.609] ng/g, which is several orders of magnitude larger than the computed frequentist 95% confidence interval of [4.690, 8.095] ng/g and indicates that the population could have cancer risk concerns. These uncertainty analysis results from the Bayesian GLN approach indicated a larger variation of Lindane soil residues, which might reflect the complex and unpredictable mechanism of pesticide residue distribution including both unfixed models and distribution parameters. In summary, Bayesian GLN model is more flexible for the dynamic evaluation of pesticide soil residue distribution, retains posteriors for future data analysis, and could better quantify the uncertainties in population health risks. Therefore, this study can provide a novel and dynamical perspective of pesticide residue distribution and help better quantify health risks.

The public health benefit and burden of mass drug administration programs in Vietnamese schoolchildren: Impact of mebendazole

BACKGROUND

Mass anthelmintic drug administration is recommended in developing countries to address infection by soil-transmitted helminthiases (STH). We quantified the public health benefit of treatment with mebendazole in eight million Vietnamese children aged 5-14 years from 2006 to 2011. This was compared to the environmental impact of the pharmaceutical supply chain of mebendazole, as the resource use and emissions associated with pharmaceutical production can be associated with a public health burden, e.g. through emissions of fine particulate matter.

METHODOLOGY

Through Markov modelling the disability due to STH was quantified for hookworm, Ascaris lumbricoides and Trichuris trichiura. For each worm type, four levels of intensity of infection were included: none, light, medium and heavy. The treatment effect on patients was quantified in Disability-Adjusted Life Years (DALYs). The public health burden induced by the pharmaceutical supply chain of mebendazole was quantified in DALYs through Life Cycle Assessment.

PRINCIPAL FINDINGS

Compared to 'no treatment', the modelled results of five-year treatment averted 116,587 DALYs (68% reduction) for the three worms combined and largely driven by A. lumbricoides. The main change in DALYs occurred in the first year of treatment, after which the results stabilized. The public health burden associated with the pharmaceutical supply chain was 6 DALYs.

CONCLUSIONS

The public health benefit of the Mass Drug Administration (MDA) averted substantially more DALYs than those induced by the pharmaceutical supply chain. These results were verified in a sensitivity analysis. The starting prevalence for each worm was the most sensitive model parameter. This methodology is useful for policymakers interested in a holistic approach towards the public health performance of MDA programs, enveloping both the treatment benefit received by the patient and the public health burden associated with the resource consumption and environmental emissions of the pharmaceutical production and supply chain.

The use of a disability-adjusted life-year (DALY) metric to measure human health damage resulting from pesticide maximum legal exposures

Most agencies around the world have developed a separate regulation frameworks for pesticides with different modes of action, likely because of the lack of a uniform quantification for health damage, which may underestimate pesticides' impact on human health and disease burden. In this study, the disability-adjusted life-year, a uniform metric used to express the human health impact and damage, was used to measure theoretical health damage resulting from maximum exposure as permitted by law to the most widely used pesticides. The total human risk characterization factors computed from chlorpyrifos and diazinon standard values through main exposure routes are generally larger than that of other widely used pesticides, and most factors of chlorpyrifos exceed the upper bounds of health risk. In addition, the damages to human health quantified from soil legal exposure to these widely used pesticides are much lower than that from exposure to drinking water or foods, which could help derive exposure allocation factors for different exposure routes. A total of 412 (28.3% of the total) computed total risk characterization factors of the 13 pesticides exceed the upper bound of tolerable risk uncertainty. Some nations, such as those in Europe, have adopted uniform and strict pesticide standard values as well as some computed risk characterization factors presented in the consensus data cluster. In addition, the results of an analysis on the geographical distribution of health risk characterization factors indicated that European nations have provided more conservative pesticide standard values in general. It is hoped that regulatory agencies can apply this uniform metric to compare and formulate legal limits for pesticides that have different modes of action.