Kiyotaka Tsunemi

Eco‐Efficiency of Advanced Loop‐Closing Systems for Vehicles and Household Appliances in Hyogo Eco‐Town

The closing of material loops is a critical challenge in industrial ecology. It relies mainly on the utilization of recovered materials/parts/products in the original and principal production system while their original function is retained at the highest level possible. In this study, advanced loop‐closing systems for the recycling of end‐of‐life vehicles and electric household appliances are first designed in “Hyogo Eco‐town.” Second, a methodology for evaluating the eco‐efficiency of these systems is developed. Finally, the eco‐efficiency of the designed advanced loop‐closing strategies for the two products is evaluated, based on the results of materials flow analysis and life‐cycle assessment. The results show that, compared with conventional recycling systems, when an industrial complex and an advanced loop‐closing system for end‐of‐life vehicles are established, the total economic value increases by 114% and the eco‐efficiency in terms of the amount of direct material input is improved by 57%. This system permits the utilization of the by‐products, wastes, and recovered materials that originate from other industrial sectors as input to production activities. In the case of end‐of‐life electric household appliances, an advanced loop‐closing strategy to lengthen the product life with parts reuse improves the eco‐efficiency in terms of carbon dioxide (CO) emissions by 4% compared with the conventional replacement of the appliance with a new product along with the material recycling option.

Assessment of the effects of the Japanese shift to lead-free solders and its impact on material substitution and environmental emissions by a dynamic material flow analysis

Lead-free electronics has been extensively studied, whereas their adoption by society and their impact on material substitution and environmental emissions are not well understood. Through a material flow analysis (MFA), this paper explores the life cycle flows for solder-containing metals in Japan, which leads the world in the shift to lead-free solders in electronics. The results indicate that the shift has been progressing rapidly for a decade, and that substitutes for lead in solders, which include silver and copper, are still in the early life cycle stages. The results also show, however, that such substitution slows down during the late life cycle stages owing to long electronic product lifespans. This deceleration of material substitution in the solder life cycle may not only preclude a reduction in lead emissions to air but also accelerate an increase in silver emissions to air and water. As an effective measure against ongoing lead emissions, our scenario analysis suggests an aggressive recycling program for printed circuit boards that utilizes an existing recycling scheme.

Risk Assessment of Short-Chain Chlorinated Paraffins in Japan

The objective of this chapter is to assess the ecological and human health risk of short-chain chlorinated paraffins (SCCPs) via the environment in Japan. First, release sources of SCCPs are identified based on the substance flow analysis, and the volume of their releases is estimated. Next, the behavior of SCCPs in the environment is estimated using a multimedia model, and the estimated SCCPs concentrations in the environment and food are validated with measured concentrations. Then, the endpoints and doses of SCCPs as the criteria for ecological and human health risk assessment are derived through the review of the existing toxicological data. Finally, risk characterization is performed based on the results of exposure assessment and dose-response assessment. As a result, it is determined that there is little need to be concerned about potential ecological risk to aquatic, sediment-dwelling, and soil-dwelling organisms in local areas and the regions in Japan. As far as human health risk is concerned, the Margins of exposure are 1.5 × 105 and 2.2 × 106, which are larger than uncertainty factors. Thus, it is determined that there is no significant human health risk via the environment.

Screening Risk Assessment of Short Chain Chlorinated Paraffins in Ecosystems Using a Multimedia Model

Short chain chlorinated paraffins (SCCPs) are persistent and highly bioaccumulative substances. The possible risks to ecosystems caused by releases of SCCPs to the environment have been assessed in the European Union and the United States of America. The study reported in this paper was a screening risk assessment of SCCPs in the ecosystems of Japan. However, the monitoring data for SCCPs in Japan were too limited to estimate the overview of exposure. Therefore, in this study, the flows and releases throughout the life cycle of these substances were estimated from international data, environmental concentrations were predicted using a multimedia model, and risk characterization was conducted. The results indicate that there is a low potential risk from SCCPs to aquatic and sediment‐dwelling organisms in most regions and local areas of Japan.

Cross-Border Impacts of the Restriction of Hazardous Substances: A Perspective Based on Japanese Solders

Despite the relevance of the global economy, Regulatory Impact Assessments of the restriction of hazardous substances (RoHS) in the European Union (EU) are based only on domestic impacts. This paper explores the cross-border environmental impacts of the RoHS by focusing on the shifts to lead-free solders in Japan, which exports many electronics to the EU. The regulatory impacts are quantified by integrating a material flow analysis for metals constituting a solder with a scenario analysis with and without the RoHS. The results indicate that the EU regulation, the RoHS, has triggered shifts in Japan to lead-free solders, not only for electronics subject to this regulation, but for other products as well. We also find that the RoHS leads to a slow reduction in environmental emissions of the target, lead, but results in a rapid increase in the use of tin and silver in lead-free solders. This indicates the importance of assessing potential alternative substances, the use of which may increase as a result of adhering to the RoHS. The latter constitutes a negative impact because of recent concerns regarding resource criticality.

PM 2.5 -related health impacts of utilizing ammonia-hydrogen energy in Kanto Region, Japan

Ammonia has emerged as a promising hydrogen carrier with applications as an energy source in recent years. However, in addition to being toxic, gaseous ammonia is a precursor of secondary inorganic aerosols. The concentration of ambient fine particulate matter (PM2.5) is intrinsically connected to public health. In this study, PM2.5-related health impacts of utilizing ammonia-hydrogen energy in Kanto Region, Japan, were investigated. It was assumed that 20% of the electricity consumption in Kanto Region, the most populated area in Japan, was supplied by ammonia-hydrogen energy. The PM2.5 resulted from incomplete ammonia decomposition was simulated by a chemical transport model: ADMER-PRO (modified version). Based on the incremental PM2.5 concentration, health impacts on the elderly (individuals over 65 years old) were quantitatively evaluated. The ammonia emission in this scenario increased PM2.5 by 11.7% (0.16 μg·m–3·y–1) in winter and 3.5% (0.08 μg ·m–3·y–1) in summer, resulting in 351 premature deaths per year. This study suggests that costeffective emissions control or treatment and appropriate land planning should be considered to reduce the associated health impacts of this type of energy generation. In addition, further in-depth research, including cost-benefit analysis and security standards, is needed.

OPERATION AND EVALUATION OF RISK COMMUNICATION SUPPORT PLATFORM FOR DECISION-MAKING OF ENVIRONMENTAL RISK ISSUES

本研究では, リスク・コミュニケーション支援のプラットフォームの効果を検証するために, 企業のPRTR対応の担当者へのヒアリングと, 北九州PCB処理事業に見られる行政担当者のリスク対応のシミュレーションによる運用実験をおこなった. その結果, 産業セクターからは, リスク・コミュニケーションのチェックポイントやコミュニケーション事例の掲載, およびインターフェースの使い易さなどに対する一定の評価がなされた. また, 行政セクターのシミュレーション結果からは, 住民説明会の戦略, 情報公開の方針, 緊急時の行政の役割などについてニーズに対応できていることを明確にした. さらに, 事業所の日常管理についての事例の掲載, 簡易的なリスク・アセスメントによるリスク・レベル判断, NIMBY型住民との対応に関する方法などが求められていることが明らかになった.

Economic Evaluation of Technical System for End-of-Life Vehicle Recycling

循環型社会システムの形成に向けて, 廃自動車(ELV)のリサイクルシステムを取り上げて評価する. ELVリサイクルシステムは, ASRに注目した再資源化率向上という目標と, 回収されるスクラップの質が重要であるが, 近年, 電装系部品に含まれるCuの混入が鉄スクラップの品位の低下を引き起こしている. ELVリサイクルに関係するセクターにおける, ASRの再資源化や減量化を目的としたさまざまな技術が進展していく中, システム全体を総合的に評価する必要がある. 本研究においては, 解体業者とシュレッダー業者の連携によって, 効率的かっ効果的にASRを削減する方法についてシナリオを立て, 費用便益分析によって検討する.ここから, 将来的な循環型社会の構築へと向けたについて考察する.