Cross-Border Impacts of the Restriction of Hazardous Substances: A

Jul 22, 2013 - This paper explores the cross-border environmental impacts of the RoHS by focusing on the shifts to lead-free solders in Japan, which e...
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Cross-Border Impacts of the Restriction of Hazardous Substances: A Perspective Based on Japanese Solders Masaaki Fuse* and Kiyotaka Tsunemi Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa Tsukuba Ibaraki 305-8569 Japan S Supporting Information *

ABSTRACT: 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.

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INTRODUCTION The restriction of hazardous substances (RoHS) regulation, which was implemented beginning in 2006, is designed to control the use of certain hazardous substances in electronics used in the EU.1 This European regulation has international implication because the RoHS covers imported electronics. As a consequence, manufacturers in exporting countries that are not part of the EU are required to comply with the RoHS.2 Such pressure is a strong impetus to phase out hazardous substances and to introduce similar regulations in non-EU countries, such as China, Japan, South Korea, Turkey, the U.S. (specifically the state of California), Thailand, and India.3−5 However, the assessment of cross-border impacts of the RoHS does not form part of the Regulatory Impact Assessment (RIA) of the RoHS, due to the focus of this process on domestic impacts.6,7 Our previous study focused on Japan, the world’s leading producer of electronics, and indicated a shift to lead-free solders in the country, through the use of material flow analysis (MFA).8 Such a shift to lead-free solders in Japan provides an evidence for the existence of cross-border impacts resulting from the RoHS. However, the extent of cross-border impacts remains unknown, because our previous MFA quantified only current lifecycle flows for solder-containing metals in Japan from 2000 to 2010. Although there are MFAs that target metals used in solders, these MFAs focus on current metal lifecycles at a certain year in the country.9−11 There is an advanced MFA for solder-containing metals that extends beyond assessment of the current situation.12 This MFA allows estimation of the effects of change in future systems, including the effect of regulatory © 2013 American Chemical Society

changes, however, this MFA cannot evaluate the cross-border impacts, as these are not considered in this global-scale assessment. An RIA for the RoHS needs to estimate and compare impacts, both with and without the RoHS, providing projections for the future.6,7 However, the aim of conventional MFA is to understand the current situation and not to assess regulatory impacts.13 Furthermore, advanced MFAs that can assess future regulatory impacts are not adequate for assessing cross-border impacts, which are the subject of this paper.12 Hence, more progress in MFA is required for conducting an RIA of the RoHS from the perspective of cross-border impacts. The application of MFA for RIA also indicates collateral effects, in terms of the assessment of substances affected by the RoHS. The hazard-less technologies required by the RoHS may bring about another resource problem.14 Many lifecycle assessments point out that lead-free solders introduced by the RoHS consume more resources than conventional lead-based solders.15−18 However, notwithstanding increasing concerns regarding resource criticality,19 existing RIAs are not sufficient for alternative substance assessment.6,7 This paper aims to assess the cross-border impacts of the RoHS, by examining shifts to lead-free solders in Japan. To quantify regulatory impacts, the framework of MFA is expanded, by integrating a MFA for solder-containing metals Received: Revised: Accepted: Published: 9028

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requirement (TMR) as a weight representing the importance of the resource. TMR expresses the amount of hidden material flows by extraction from lithospheric and exospheric resources. TMR for 1 kg of tin, lead, silver, and copper used in solders are 2500 kg, 28 kg, 4756 kg, and 360 kg, respectively.21 The scenario analysis and MFA used in this study are explained below. Scenario Analysis. This was conducted to obtain the lifecycle flows for solder-containing metals in Japan, with and without the RoHS. This scenario analysis provides the inputs to soldering in Japan, with and without the RoHS scenarios in MFA (see PS in SI Figure S-1), using the following equation:

with a scenario analysis for the RoHS. The integration of both MFA and scenario analysis is addressed in the subsequent Materials and Methods section. The Results section indicates estimated results for cross-border impacts, from the perspectives of hazardous substance and resource management. Findings in this paper are summarized in the final Discussion section.

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MATERIALS AND METHODS A challenge with RIA lies in the absence of control data, for a nonregulated situation; this is in contrast with the typical situation in the natural science, where control and experimental data can be compared. Thus, counterfactual thinking which compensates for the absence of a control experiment, is needed.20 The first point of assessment for cross-border impacts of the RoHS is to use counterfactual thinking in a non-EU country. In this assessment, RoHS impacts were assessed by comparing the actual situation in Japan, following the introduction of the RoHS in 2006, with the hypothetical situation in Japan, had the RoHS not been introduced in the EU. For the actual situation resulting from implementation of the RoHS, material flows associated with the shift to lead-free solders in Japan (obtained from our previous study) were used.8 However, new estimations for the hypothetical situation existing in the absence of the RoHS were also needed. In addition to counterfactual thinking, there are ways to compare the situation before and after the implementation of a regulation, or to compare a regulated country with a non regulatied country. However, these methods cannot correctly evaluate regulatory impacts, because nonregulatory factors are affected by differences over time and across countries; for example, differences in the economic situation. The second element in our assessment is focused on the long-term. Our previous work indicates that the shift to leadfree solders in Japan occurred progressively between 2000 and 2010. Substantial amounts of lead remain in existing stock, due to long product lifespan.8 This means that the assessment of RoHS impacts requires a long time-scale, in order to accurately understand the phase-out of lead in society over 10 years. Overall, to assess cross-border impacts resulting from the RoHS, a new approach to MFA is needed, that considers counterfactual thinking and a long evaluation period. Thus, this paper integrates a MFA with a scenario analysis for future prospects, through the case study of solders used in Japan. The scenario analysis utilized incorporates two types of amounts of soldering, corresponding to the scenarios with and without the RoHS. Based on the scenario analysis results, MFA estimates the lifecycle flows for solder-containing metals in Japan, with and without the RoHS. The system boundary of this MFA is shown in Supporting Information (SI) Figure S-1, based on the framework developed by the present authors.8 The time-scale of our assessment spans 40 years, from 2000 to 2040, to reflect a long evaluation period. Finally, a comparison of scenarios with and without the RoHS, using this integrated method, enables the identification of regulatory impacts. The target solder addressed in this study is the same as in our previous study, that is, lead-based solder (63Sn37Pb solder) and leadfree solder (96.5Sn3Ag0.5Cu solder).8 From the hazardous substance and resource aspects, the study focuses on emissions to the environment of regulated lead, and resource use of alternative metals. In the assessment of resource use, domestic inputs of refined metals for solder-containing metals (RP + MR in SI Figure S-1) are unified, by using the total material

⎧ ⎪(1 − lf ts) × swj × TSt (j = 0) PSjts = ⎨ ⎪ (j = 1) ⎩ lf ts × swj × TSt

(1)

where, PSjts represents inflows for solder type j (0, lead-based solder; 1, lead-free solder) in year t for scenario s, into the soldering stage. lfts represents the share of lead-free solders to total solder supply in Japan, for scenario s in year t. swj and TSt denote the specific weight for solder type j and the total soldering volume in year t. The share of lead-free solders with the RoHS scenario (s = 0) is described by the following logistic regression model. For the scenario without the RoHS scenario (s = 1), the share of lead-free solders is zero at all times. ⎧ 1 (s = 0) ⎪ 1 + exp(1010 + 0.504 × t ) lf ts = ⎨ ⎪ 0 (s = 1) ⎩

(2)

Parameters in the logistic regression model are determined by the share of lead-free solders from 2002 to 2010 reported in our MFA under high model fitting, when the multiple correlation coefficient adjusted for the degrees of freedom (ad.R2) is 0.95.8 The total soldering volume in year t is given by expanding a previous econometric model for solder in Japan.22 Because previous econometric models enabled a long-term forecast to estimate a log−linear model with socioeconomic variables (e.g., GDP per capita), the same framework was applied here. Furthermore, our model added new factors for trends, popularity of green products (such as energy-saving home electronics), and the economic recession that occurred after the oil shortage and the fall of Lehman Brothers. ln TSt = 91.6 + 2.99 × ln X t − 0.7 × (ln X t )2 − 0.433 × t + 0.409 × lf ts = 0 − 0.205 × DO − 0.264 × DL

(3)

where, X represents GDP per capita in Japan. The variable t is the year and is used as the index for trend. Given the difficulty in identifying a variable for popularity of green products, this is substituted by the share of lead-free solders within the RoHS scenario. DO and DL are dummy variables representing the oil shortages in 1974 and 1975, and the fall of Lehman Brothers in 2008. The model parameters are estimated using the associated statistics from 1970 to 2010 with 0.74 for ad.R2.23,24 The future GDP per capita for the prediction is obtained from official economic forecasts for Japan.23,24 Material Flow Analysis. The MFA used in this study is the same as the previous MFA developed by the present authors.8 Hence, the explanation of this MFA is given in another publication.8 Our previous MFA estimated the lifecycle flows of 9029

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Figure 1. Estimation results from the scenario analysis, with and without the RoHS.

consumer concerns to eco-friendly products.2 The share of electronics targeted in the RoHS to total soldering in Japan is 41% in 2010, based upon our previous estimation, whereas the share of lead-free solders was over 80% in 2010.8 Hence, it is found that the RoHS has cross-border impacts on the Japanese solder market, and that the regulatory impacts spill over from target electronics to nontarget products such as automobiles and industrial machines. We also discovered a long-term reduction trend in the total soldering volume for both lead-based and lead-free solders in Japan, due to the stagnation of the GDP and the population based on public forecasts (see (b) in Figure 1).23,24 This situation leads to a reduction in soldering amounts for both lead-based and lead-free solders after 2010 excluding the effects of RoHS (see (c) and (d) in Figure 1). Overall, our scenario analysis indicates that, with the RoHS scenario, lead-free solders have been used as a substitute for lead-based solders in Japan for a ten-year period starting in 2000. However, in the scenario without the RoHS, the use of lead-based solders would have continued for quite a while. Note that the total soldering amounts for both types of solder with the RoHS scenario are not the same as those for the scenario without the RoHS because of the difference between the specific weights of leadbased and lead-free solders. The estimation results of lifecycle flows for solder-containing metals in Japan, aggregated between 2000 and 2040 in the scenarios with and without the RoHS, are displayed in Figure 2. The results for silver and copper in the scenario without the RoHS are not displayed here because lead-free solder, which

solder-containing metals in Japan between 2000 and 2010, corresponding to the situation of the RoHS scenario.8 This MFA, however, includes additional estimations, with and without the RoHS scenario between 2000 and 2040. The added estimation is determined by soldering amounts, with and without the RoHS, from scenario analysis and conventional MFA parameters. The models for in/outflows at each life stage in the MFA used in this study are summarized in SI Table S-1. The details of the model parameters in SI Table S-1 are explained in our previous work.8

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RESULTS The estimation results of the scenario analysis with and without the RoHS given by eqs 1−3 are shown in Figure 1; these results are the inputs required to determine the results of the dynamic MFA. The results show that the shift to lead-free solders in Japan progressed rapidly from 2000 to 2010. This period includes the introduction of the RoHS .The shift is anticipated to be completed by 2020 (see (a) in Figure 1). This means that Japanese solder suppliers prepared for the production of leadfree solders from the early 1990s, before RoHS enforcement,25 and that Japanese solder buyers promoted the shift to lead-free solders, not only for electronics targeted by the RoHS, but for other products as well. The reason that these shifts occurred also in products that are not targeted by the RoHS is marketing-related- Japanese corporations embrace lead-free products as a an opportunity to move from products of high 9030

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Figure 2. Estimation results of lifecycle flows for solder-containing metals in Japan, aggregated over the period 2000 to 2040, for scenarios with and without the RoHS. Unit: Gg for solid arrows, Mg for dotted arrows (emissions to environment).

that tin entering the waste management system in Japan is not recycled. Hence, solder-containing tin, owing to its lower toxicity than lead, is considered to be a critical resource for Japan.26 A comparison between both scenarios from the perspective of resource management suggests that the RoHS increases the consumption of tin in Japan trough material substitution in the shift to lead-free solders. For solder-containing lead, which is a hazardous substance restricted mainly through the RoHS, the comparison of both scenarios shows visible reduction in lead lifecycle flows as a result of this regulation (see (c) and (d) in Figure 2). It is found that the RoHS reduce emissions to air from the incineration by 50%, with these accounting for 86% of total emissions. It is also found that RoHS impacts on lead lifecycle flows are different before and after the use stage. The lifecycle flows before the use stage appear to exhibit a great reduction in RoHS impacts than those after the use stage. This is because of the long product lifespan, as described in the case of above. In the case of MFA results for 2010 (SI Table S-2−S-15), the lifecycle flows before use in the scenario with the RoHS decreased, in comparison with those in the scenario without the RoHS, due to the rapid shifts to lead-free solders. However, the impacts of the RoHS were not observed from lifecycle flows

contains both metals, was not introduced in this scenario (see (d) in Figure 1). The details of the estimation results for the MFA are summarized in SI Tables S-2−S-15. Considering results for tin (Figure 2 (a) and (b)), the quantity of lifecycle flows in the scenario with the RoHS were considerably larger than in the scenario without the RoHS, due to the high fraction of tin in lead-free solder. Aggregated over a 40 year period, these differences in lifecycle flows in both scenarios represent the cross-border impacts of the RoHS in Japan. It would be difficult to identify RoHS impacts on the basis of snapshot results for one year. For example, in the case of the MFA results for 2010 (SI Table S2−Table S-15), the increase in lifecycle flows resulting from the RoHS is limited to before the use stage. The lifecycle flows after the use stage are not substantially different across the two scenarios, because of the long product lifespan, which means that flows continue past the use of lead-based solders, during the waste management stage. Therefore, the impacts of the RoHS on lifecycle flows after the use stage appear much later, when the shift to lead-free solders in end-of-life products is completed. In 2010, the share of solders in the total market for tin was over 10% in Japan.8 Our results also indicate that over 95% of tin supply in Japan originates in foreign counties, and 9031

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Figure 3. Estimation results for cross-border impacts of the RoHS on environmental emissions and resource consumption in Japan.

faster than the reduction in environmental emissions because the increase peaks around 2012. This is because domestic inputs correspond directly with the shift to lead-free solders in the early lifecycle. Overall, we find that the RoHS leads to a slow reduction in lead emissions to the environment, but it results in a rapid increase in the use of tin and silver in lead-free solders. The cross-border impacts of the RoHS estimated here are expected to be subject to a large degree of uncertainty, due to the long assessment span and to the large number of parameters in the MFA.8 Given the difficulties in quantifying uncertainties in the MFA, the analysis of uncertainty is a future issue in MFA research field.9 In this regard, we qualitatively examine the validity of identified cross-border impacts of the RoHS (Figure 3). With regard to the shift to read-free solders by 2010 (as indicated in Figure 1(a)), based on actual values available up to this point in time, the presence or absence of the regulatory impacts appears to be valid. Moreover, because our MFA is based on statistics from 2000 to 2010, the estimation results for the cross-border impacts are expected to have relatively high reliability over the decade. Hence, the trend that can almost explain the observed pattern of resource use over the decade is be based on appropriate interpretation. On the other hand, the trend in environmental emissions, with a peak in decreases occurring around 2030, is expected to be subject to considerable uncertainty. These uncertainties do not, however, necessarily lead us to negate the emphasis in our findings on the time lag between the increased peak in resource use, and the decreased peak in environmental emissions resulting from the RoHS. This time lag is strongly affected by product lifespan and emission factors at the incineration stage, as per the models in the MFA (see SI Table S-1). This MFA used relatively high quality data for product lifespans in Japan, which is an advanced country with respect to data infrastructure on product lifespans.28,29 The decrease to a low value of incineration emission factors in the future was not considered, because bag filters with dust collection efficiencies of 99.9% are now widely used.30 Therefore, despite uncertainties relating to the crossborder impacts, significant changes in the findings obtained from our regulatory impact assessment are not considered.

after the use stage. On the other hand, the impacts of the RoHS on the resource use of lead can be ignored, here because the market share of lead in solder was less than 1% in 2010.8 The estimation results of lifecycle flows for silver and copper used in solders will be used to represent the impacts of the RoHS directly, because there are no lifecycle flows for these metals in the scenario without the RoHS (see (e) and (f) in Figure 2). Hence, the impacts of the RoHS are simply considered to increase throughout lifecycle flows for both metals. The respective impacts for both metals were smaller than those for tin and lead, according to the metal composition in solder. However, the impacts for silver should be noted, because the share of silver used for solder in the total silver market was over 10% in 2010.8 Incidentally, the market share of copper for solder is small, less than 0.1% in 2010. 8 Furthermore, silver has a high price and high toxicity, although the latter is far lower than that of lead.26 Moreover, a price increase of silver in the near future is predicted due to rapid growth in the use of photovoltaic cells, which are the main users of silver.27 Therefore, our results indicate that the RoHS increases silver use and silver emissions to the environment. From the MFA results for solder-containing metals shown in Figure 2, the impacts of the RoHS can be divided into reduction in environmental emissions of lead and increase in resource use of tin and silver in the manufacture of lead-free solder. The time trend for the cross-border impacts of the RoHS in Japan, from the perspective of hazardous substance and resource management, is shown in Figure 3. In this figure, environmental emission focuses on lead, and its reduction due to the RoHS was estimated by subtracting the results of the scenario without the RoHS from those of the scenario with the RoHS. Although resource use shown in Figure 3 covers all metals in solders based on the same subtraction as environmental emissions, when assessing the increase in resource use by the RoHS, domestic inputs of refined metals for four soldercontaining metals are unified by using the TMR. The results for the reduction in lead emission to the environment show that the RoHS reduces lead emissions and that lead emissions peak around 2030. The reason for the late reduction peak in environmental emissions is due to long product lifespans and to the high contribution of air emissions from the incineration stage in the later parts of the lifecycle. In terms of results for increased resource use, it is found that the RoHS increases the TMR values of domestic inputs, mainly for refined tin and silver. However, the increase in resource use is

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DISCUSSION This study is a first estimation of induced cross-border impacts resulting from the RoHS. We used MFA and scenario analysis to determine that the RoHS triggered a rapid shift to lead-free 9032

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solders in Japan and led to drastic changes in lifecycle flows for solder-containing metals. These results indicate that the hazardous substance regulation initiated by the EU has “cross-border” impacts. The cross-border impacts addressed in this paper are projected to occur in South Korea, Taiwan, and China, which, like Japan, export electronics to the EU. We also discovered spillover effects on products other than electronics in the assessment of the cross-border impacts of the RoHS. The RoHS may be a strong trigger for the use of hazard-free substances not only in electronic products subject to the regulation, but also in related industries in the affected counties. Our assessment of RoHS impacts covered not only the phasing out of lead in Japanese solder lifecycles but also resource problems that will occur as a result. These problems involve both the trade-off between environmental emissions for lead, and the resource use due to the substitution of tin and silver, as was already pointed out by previous LCAs and MFAs for solders.8,12,15−18 Such trade-offs, through shifts to lead-free solders in Japan between 2000 and 2010, were explored in our previous MFA.8 However, these results could not show RoHS impacts over a long assessment span. The success of this study is in quantifying the dynamics in the trade-offs between the reduction in environmental emissions and the increase in resource use, both resulting from the RoHS. In short, we indicate, based on quantification, that the RoHS leads to a slow reduction in lead emissions to the environment, but to a rapid increase in the use of tin and silver in lead-free solder. This highlights the importance of assessing changes in levels of used of alternative substances as a result of the RoHS; this is a potential negative impact, because of recent concerns regarding resource criticality.19 Our study focused only on solders in Japan, but our results can be successfully used to identify the cross-border and negative impacts caused by the RoHS. These impacts could be applied to other target products, other countries, and other lead substitutes. Attention should be paid to the negative impacts of the RoHS on resource management, because scarce metals tend to be used as substitutes for hazardous substances (e.g., from mercury in fluorescent lamps to gallium in light-emitting diode lamps, and from cadmium in nickel−cadmium batteries to lithium in lithium-ion batteries).31,32 Therefore, RIA for the RoHS and similar regulations in other countries need to consider cross-border impacts including environmental impacts of substitutes from the perspective of resource criticality. When conducting an RIA based on MFA for future prediction, as proposed in this paper, a certain level of uncertainty in the estimated regulatory impacts cannot be avoided. However, the manner by which such uncertainties are reduced is significant for appropriate regulation making. Because this paper focused on qualitative aspects and included only limited examination of the uncertainties, future issues for quantifying and reducing the uncertainties remain relevant. Although a solution to these issues would require adequate uncertainty analysis, such analysis would be difficult to conduct using MFA, given a number of different data sources and models. Hence, the first step may be to identify effective parameters through sensitive analysis, focusing on material flows at waste management and recycling stages, with the latter two being highly model-dependent when statistics infrastructure is poor.

Policy Analysis

ASSOCIATED CONTENT

* Supporting Information S

Additional information as noted in the text. This information is available free of charge via the Internet at http://pubs.acs.org/.

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AUTHOR INFORMATION

Corresponding Author

*Phone: +81-29-861-8090; fax: +81-29-861-8411; e-mail: [email protected]. Notes

The authors declare no competing financial interest.

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REFERENCES

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