Massimo Pizzol

Long-term human exposure to lead from different media and intake pathways.

Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2μg/dl in children and almost 1μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented.

Normalisation and weighting in life cycle assessment: quo vadis?

PurposeBuilding on the rhetoric question “quo vadis?” (literally “Where are you going?”), this article critically investigates the state of the art of normalisation and weighting approaches within life cycle assessment. It aims at identifying purposes, current practises, pros and cons, as well as research gaps in normalisation and weighting. Based on this information, the article wants to provide guidance to developers and practitioners. The underlying work was conducted under the umbrella of the UNEP-SETAC Life Cycle Initiative, Task Force on Cross-Cutting issues in life cycle impact assessment (LCIA).MethodsThe empirical work consisted in (i) an online survey to investigate the perception of the LCA community regarding the scientific quality and current practice concerning normalisation and weighting; (ii) a classification followed by systematic expert-based assessment of existing methods for normalisation and weighting according to a set of five criteria: scientific robustness, documentation, coverage, uncertainty and complexity.Results and discussionThe survey results showed that normalised results and weighting scores are perceived as relevant for decision-making, but further development is needed to improve uncertainty and robustness. The classification and systematic assessment of methods allowed for the identification of specific advantages and limitations.ConclusionsBased on the results, recommendations are provided to practitioners that desire to apply normalisation and weighting as well as to developers of the underlying methods.

External costs of atmospheric Pb emissions: valuation of neurotoxic impacts due to inhalation

BackgroundThe Impact Pathway Approach (IPA) is an innovative methodology to establish links between emissions, related impacts and monetary estimates. Only few attempts have so far been presented regarding emissions of metals; in this study the external costs of airborne lead (Pb) emissions are assessed using the IPA. Exposure to Pb is known to provoke impacts especially on childrens cognition. As cognitive abilities (measured as IQ, intelligence quotient) are known to have implications for lifetime income, a pathway can be established leading from figures for Pb emissions to the implied loss in earnings, and on this basis damage costs per unit of Pb emission can be assessed.MethodsDifferent types of models are here linked. It is relatively straightforward to establish the relationship between Pb emissions and consequent increase in air-Pb concentration, by means of a Gaussian plume dispersion model (OML). The exposed population can then be modelled by linking the OML-output to population data nested in geo-referenced grid cells. Less straightforward is to establish the relationship between exposure to air-Pb concentrations and the resulting blood-Pb concentration. Here an Age-Dependent Biokinetic Model (ADBM) for Pb is applied. On basis of previous research which established links between increases in blood-Pb concentrations during childhood and resulting IQ-loss we arrive at our results.ResultsExternal costs of Pb airborne emissions, even at low doses, in our site are in the range of 41-83 €/kg emitted Pb, depending on the considered meteorological year. This estimate applies only to the initial effects of air-Pb, as our study does not address the effects due to the Pb environmental-accumulation and to the subsequent Pb re-exposure. These are likely to be between one and two orders of magnitude higher.ConclusionsBiokinetic modelling is a novel tool not previously included when applying the IPA to explore impacts of Pb emissions and related external costs; it allows for more fine-tuned, age-dependent figures for the external costs from low-dose exposure. Valuation of additional health effects and impacts e.g. due to exposure via ingestion appear to be feasible when extending the insights from the present pilot study.

A flexible parametric model for a balanced account of forest carbon fluxes in LCA

PurposeDespite a mature debate on the importance of a time-dependent account of carbon fluxes in life cycle assessments (LCA) of forestry products, static accounts of fluxes are still common. Time-explicit inventory of carbon fluxes is not available to LCA practitioners, since the most commonly used life cycle inventory (LCI) databases use a static approach. Existing forest models are typically applied to specific study fields for which the detailed input parameters required are available. This paper presents a simplified parametric model to obtain a time-explicit balanced account of the carbon fluxes in a forest for use in LCA. The model was applied to the case of spruce as an example.MethodsThe model calculated endogenous and exogenous carbon fluxes in tons of carbon per hectare. It was designed to allow users to choose (a) the carbon pools to be included in the analysis (aboveground and belowground carbon pools, only aboveground carbon or only carbon in stem); (b) a linear or sigmoidal dynamic function describing biomass growth; (c) a sigmoidal, negative exponential or linear dynamic function describing independently the decomposition of aboveground and belowground biomass; and (d) the forest management features such as stand type, rotation time, thinning frequency and intensity.Results and discussionThe parametric model provides a time-dependent LCI of forest carbon fluxes per unit of product, taking into account the typically limited data available to LCA practitioners, while providing consistent and robust outcomes. The results obtained for the case study were validated with the more complex CO2FIX. The model ensures carbon balance within spatial and time delimitation defined by the user by accounting for the annual biomass degradation and production in each carbon pool. The inventory can be used in LCA studies and coupled with classic indicators (e.g. global warming potential) to accurately determine the climate impacts over time. The model is applicable globally and to any forest management practice.ConclusionsThis paper proposes a simplified and flexible forest model, which facilitates the implementation in LCA of time-dependent assessments of bio-based products.

Plastic value chains: Case: WEEE (Waste Electric and electronic equipment) in the Nordic region

This project identifies thousands of tonnes per annum of potential enhanced plastics recycling from Nordic electronic waste. Plastics recycling does not always feature prominently in waste treatmen ...

Identifying marginal supplying countries of wood products via trade network analysis

PurposeThe consequential inventory modeling approach for life cycle assessment implies that an increase in the demand for a specific product is met by the marginal suppliers within the market. The identification of marginal suppliers is however complicated by difficulties in defining appropriate geographical market delimitations. In this study, an advanced system thinking approach is proposed to address this challenge in the identification of marginal supplying countries of wood products.MethodsGroups of countries which represent geographical markets are identified from trade data by using a network analysis-based clustering technique. Within these markets, marginal supplying countries are selected based on positive historical increments. The analysis covers 12 different products and all countries in the world using trade data for the period 1998–2013.Results and discussionGlobal indices allow differentiating how product-specific trade networks are separated into communities and how interconnected these networks are. Large differences between products and minor differences between trade years are observed. Communities identified for each product tend to overlap with existing geographical regions and seem thus realistic. By combining this information with product-specific production increment rankings, marginal supplying countries of wood products were identified.ConclusionsThe identified geographical market delimitation is a key for proper consequential life cycle assessment (LCA) inventory modeling in areas such as timber-based construction and biomass-based energy production. The method can in principle be applied to any product for which trade network data are available and ideally should be accompanied by a detailed analysis of technological constrains within the identified supplying country.

Extending the Multiregional Input-Output Framework to Labor-Related Impacts: A Proof of Concept

Given the high potential shown by the recent developments in environmentally extended and multiregional input†output (I†O) analysis, a natural step would be to extend this theoretical framework beyond the environmental dimension to include the social dimension, in line with parallel advancements in social life cycle assessment. The ideal results would be a multiregional I†O database to investigate not only environmental footprints, but also social footprints. Qualitative and subjective characteristics of social issues, complex impact pathways, and data scarcity challenge the extension of the I†O framework to social impacts. These challenges are addressed in this study where the Exiobase database was extended with new data on five quantitative indicators available from the International Labor Organization: employment; working hours; salary; occupational accident cases; and unemployment. This required modeling steps, such as the disaggregation of data from sector to product group level, and filling the data gaps for missing countries by primary data collection or interpolation. A characterization step where indicator values are converted into social impacts on human productivity and human well†being measured in quality†adjusted life years was then performed. The results show an appreciable match between the databases, with justifiable interpolations for missing countries. The study demonstrates how to obtain an open and quantitative I†O database extended with indicators on labor†related impacts and discusses approaches to overcome the challenges of this process.

Comparative life cycle assessment of fired brick production in Thailand

PurposeFired bricks are an essential construction material in Thailand where the majority of fired brick kilns use rice husk as feedstock. Given the increasing demand of rice husk from other industries, alternative feedstocks are needed for future fired brick production. This life cycle assessment (LCA) study investigates the environmental burden of Thai brick production using different biomass types.MethodsThree biomass fuels for fired brick production were compared: cane leaves, rice straw, and rice husk. Both the attributional and consequential modeling approaches were applied. Separated inventories were compiled using different databases: ecoinvent v. 3 and the Thai National Life Cycle Inventory (TH-LCI). Overall, this study includes a total of nine scenarios, for which characterized results were calculated using the Stepwise method. Differences in biomass scenario, modeling approach, and database used were tested via analysis of variance using four distinct fired brick production plants as replications.Results and discussionOverall, using cane leaves and rice straw gives lower impacts than using rice husk. The largest burden for cane leaves and rice straw scenarios comes from the burning process, while using electricity and using fertilizers for rice cultivation were the most contributors for rice husk scenario. However, different modeling approaches yield mostly significantly different results and the consequential results were lower than the attributional ones. Regarding database choice in attributional modeling approach, results were lower when using TH-LCI compared with ecoinvent.ConclusionsUsing cane leaves and rice straw as fuels in fired brick production are better scenarios than using rice husk. Nevertheless, factors related to season, size, and collection effort should be considered in the large-scale use of these biomasses. For database choice, ecoinvent is currently recommended over TH-LCI despite the higher geographical representativeness of the latter.

Identifying marginal suppliers of construction materials: consistent modeling and sensitivity analysis on a Belgian case

PurposeThe identification of marginal suppliers is a key element of consequential LCA. This study investigates how systematically the identification of marginal suppliers can be performed across different products, while maintaining consistent modeling choices. Some products relevant for the Belgian construction sector are taken as a case study.MethodsTo gain insight in the current practice of identifying marginal suppliers, 30 recent studies have been reviewed. Based on the findings of the review, a method was proposed to identify geographical market boundaries from trade data and sensitive suppliers from production data. Both retrospective and prospective approaches to anticipate the future effect of a change in demand were taken into account. The method was applied to compute both a retrospective and a prospective marginal supplier’s mix per product. Finally, the effect of the modeling choices on the size of geographical market boundaries and marginal mixes was estimated via regression analysis.Results and discussionThe forecasts and marginal mixes obtained matched with those from the existing literature, although clear differences in results are observed between the retrospective and prospective approach. Deviations from default assumptions in LCA were observed as well, such as large regional geographical markets for cement and aggregates instead of local ones. The statistical sensitivity analysis showed that identifying geographical market boundaries has the largest effect on the final marginal mix and that these markets are relative stable over time.ConclusionsThe proposed method and corresponding sensitivity analysis is an attempt to gain insight into the effect of modeling choices in the context of the identification of marginal suppliers for consequential LCA. It can in principle be applied to any product for which trade and production data are available. The proposed method helps to identify marginal mixes on a consistent and transparent way, to improve the robustness of the results in future consequential LCAs.

Plastic value chains: Case: WEEE (Waste Electrical and Electronic Equipment) : Part 2 Report

This project identifies improvements in plastics recycling from Nordic electronic waste. Limited improvement is possible through modest changes in the existing value chain, such as ensuring that wa ...