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Article

Social Sustainability of Raw Rubber Production: A Supply Chain Analysis under Sri Lankan Scenario

by
Pasan Dunuwila
1,*,
V. H. L. Rodrigo
2,
Ichiro Daigo
1 and
Naohiro Goto
3
1
Research Center for Advanced Science and Technology, The University of Tokyo, 4 Chome-6-1 Komaba, Meguro-ku, Tokyo 153-0041, Japan
2
International Centre for Research in Agroforestry (ICRAF), D. P. Wijesinghe Mawatha, Pelawatta, Battaramulla 10120, Sri Lanka
3
Faculty of Information Networking for Innovation and Design (INIAD), Toyo University, 1-7-11 Akabanedai, Kita-ku, Tokyo 115-0053, Japan
*
Author to whom correspondence should be addressed.
Sustainability 2023, 15(15), 11623; https://doi.org/10.3390/su151511623
Submission received: 2 June 2023 / Revised: 21 July 2023 / Accepted: 25 July 2023 / Published: 27 July 2023
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Abstract

:
Raw rubber production is the sole foundation for the rubber product industry, rendering raw rubber to manufacture essential commodities to mankind, such as tires, condoms, surgical gloves, and so forth. Raw rubber production involves various stakeholders; however, literature focusing on the social impacts of the supply chains of raw rubber production has hereto been absent. Social life cycle assessment, a popular tool to assess the social impacts of a product or process and was deployed herein to assess the social profiles of three Sri Lankan raw rubber supply chains (crepe rubber, concentrated latex, and ribbed smoked sheets) in a cradle-to-gate manner. The Social Hotspots Database v4 on Sima Pro v9.3 was used for the analysis. Results indicated that Governance, Labour rights & decent work had been affected due to Corruption and Freedom of association & collective bargaining issues, mainly in Belarus and China. Proposed improvement options to address these touchpoints were found to be effective. If the importation of K-fertilizer shifted into countries with lower risks, such as Canada, Israel, and Lithuania, overall social risks associated with Corruption and Freedom of association & collective bargaining could be reduced by ca. 36% and 25%, respectively. As a result, social risks in the impact described above categories, i.e., Governance and Labor rights & decent work, were reduced by ca. 35–41% and ca. 17–20%, respectively. Managers may pay thorough attention to the hotspots identified herein in the first place and try to avoid them as much as possible. They may consider importation from the aforesaid low-risk countries while weighing the trade-offs with economic and environmental aspects.

1. Introduction

The natural rubber industry is essential in human life, providing indispensable items such as tires, condoms, infant pacifiers, surgical gloves, and many more [1,2]. Natural rubber is derived from the sap of rubber trees (Hevea brasiliensis), grown in tropical regions such as Asia, Africa, and South America [3,4]. The industry significantly impacts global economic growth and employs millions of people in developing countries [2,5,6]. The global natural rubber market is estimated to be worth ca. USD 30 billion in 2022, with Asia holding the largest share of ca. 92% [7].
Raw rubber production is the sole foundation for the natural rubber industry, providing raw rubber to manufacture numerous commodities, as mentioned in the preceding paragraph [8]. The bark of the rubber tree is tapped to obtain latex which is then processed into different raw rubber products, including crepe rubber, concentrated latex, and ribbed smoked sheets (RSS) [9]. Crepe rubber is produced by coagulating rubber latex from a rubber tree, dried, and rolled into thin sheets. Crepe rubber is often used in pharmaceutical items, footwear, and industrial applications such as belts, hoses, and gaskets [5]. Concentrated latex is a type of rubber processed through centrifugation, which further separates the rubber particles from the liquid. Centrifuged latex is often used in products that follow the dipping process, such as surgical gloves and condoms [1,10]. Ribbed smoked sheets rubber is a rubber sheeting manufactured with low-cost machinery at the lowest cost, but this gives high quality if processed properly [11,12]. This rubber is commonly used in tires, rubber bands, and mechanical items [11,13].
In raw rubber production, significant amounts of electrical and heat energy, chemicals, fresh water, and labor are involved [2,3,13]. Also, having many factory employees from the local community, there is a close association between the local community and raw rubber manufacturers [14].
With the said nature, the raw rubber sector has faced various economic, environmental, and social challenges. Economic issues include material use inefficiency, poor worker productivity, and higher production expenses [15,16,17]. Raw rubber production releases toxic chemicals into the environment, especially through wastewater [18]. These chemicals can harm people and wildlife [19,20]. Further, it generates large amounts of greenhouse gases, including carbon dioxide and methane, due to the heavy use of electricity and firewood [1,5,11,21,22]. In addition, the social impact of the natural rubber industry is also significant. The workers in the industry are typically poor and vulnerable to exploitation. They are often paid low wages and other facilities. Also, pollution-triggered community struggles have been reported [17].
Several studies have tried to address the above economic and environmental issues [4,10,23]. Earlier, we endeavored to enhance the environmental and economic sustainability of the production of crepe rubber [5,24], concentrated latex [1], and RSS [11]. However, literature focusing on the social impacts or issues of raw rubber production has been limited.
Social life cycle assessment (SLCA) is a tool commonly used in scientific research to assess the overall social impacts of products. Despite its widespread use, methodology development in SLCA is still progressing [25]. This systematic approach can assist companies in administering their supply chains and promoting social responsibility and sustainability by evaluating products’ social and socioeconomic aspects throughout their life cycle [26,27]. Hence, it has been applied to different product value chains for social hotspots and improvements, using SLCA databases as a data source (see Table 1).
We also attempted to analyze the social impacts of a crepe rubber processing estate in Sri Lanka using a novel social life cycle assessment framework [14], being a site-specific analysis that had no capability of capturing the social hotspots along the supply chain. This conveys that studies analyzing the social sustainability of the entire raw rubber production supply chain are absent. As mentioned in the preceding paragraph, such an attempt is crucial in establishing the overall social sustainability of the natural rubber industry. To address this gap, we conduct SLCA focusing on three main raw rubber supply chains in Sri Lanka (crepe rubber, concentrated latex, and RSS), a country that ranks as the 13th largest rubber producer in the world and renowned as the largest exporter of best high-quality crepe rubber to the global market [14,28,29]. Crepe rubber, concentrated latex, and RSS comprise a share of ca. 90% of inland raw rubber production [30].
Table
Table 1. Social life cycle assessments on different product supply chains and the placement of our study. SLCA, PSILCA, and SHDB refer to the Social life cycle assessment, Product Social Impact Life Cycle Assessment, and Social hotspot database.
Table 1. Social life cycle assessments on different product supply chains and the placement of our study. SLCA, PSILCA, and SHDB refer to the Social life cycle assessment, Product Social Impact Life Cycle Assessment, and Social hotspot database.
Author (Year)Area of ApplicationScopeSLCA Database in UseContent
Our studyRaw rubber production Cradle-to-gateSHDBOur paper appraises the social footprint of three main raw rubber supply chains in Sri Lanka (i.e., crepe rubber, concentrated latex, and RSS), seeks hotspots, and evaluates the potential degree of improvement if those hotspots are addressed.
Arzoumanidis and D’Eusanio [27] (2023) Accommodation FacilityGate-togateSHDBThis paper evaluates the social footprint of the supply chain of an Italian accommodation facility and identifies the hotspots.
Tragnone et al. [26] (2023)Confetti production Cradle-to-gatePSILCAThis study compares the potential social risks of traditional almond-sugared confetti and Tenerelli-sugared almonds made by the same company in Italy.
Shi et al. [31] (2023)Lithium iron phosphate battery production Cradle-to-gateSHDBThis study identifies the social profiles of three key Lithium iron phosphate battery production supply chains in China, Japan, and South Korea and avenues for their improvements.
Akhtar et al. [32] (2023) Green hydrogen production via water electrolysis powered by renewable electricity from solar photovoltaic and wind farmsCradle-to-gatePSILCAThe study focused on Green hydrogen production in seven countries (the US, Chile, South Africa, Saudi Arabia, Oman, Australia, and China) to pinpoint social hotspots across respective value chains.
Iribarren et al. [33] (2022)Green methanol and conventional fossil methanol productionCradle-to-gatePSILCAThis study identifies the most socially sound supply chain between Green and conventional fossil methanol supply chains (based in the US) by identifying social hotpots in respective supply chains.
Aranda et al. [34] (2021)Meat productionCradle-to-gatePSILCA This study quantifies the social footprint of a specific pork product supply chain based in Spain.
Martin and Herlaar [35] (2021)Sweater production supply chains that use different types of woolCradle-to-gatePSILCAThis study compares the social profiles of sweater production based on two waste wool supply chains in Europe to those of the same made of two conventional wool supply chains based in Australia and Uruguay.
Herrera Almanza et al. [36] (2020)Textile productionCradle-to-gatePSILCAThis paper identifies the social hotpots of a value chain of a T-shirt retailed in the Netherlands.
Werker et al. [37] (2019) Rare earth NdFeB permanent magnets production Cradle-to-gatePSILCAThis study investigates the potential social risks of rare earth permanent magnet production across three distinct production locations and their corresponding value chains. These locations include a fully Chinese-based operation, a chain consisting of Australian and Malaysian processes, and a third chain that combines processes in the United States and Japan.
Norris et al. [38] (2019)Computer production Cradle-to-gateSHDBThis paper evaluates the social footprint of a computer manufactured in the US, considering its upstream supply chains, and seeks improvements.
Takeda et al. [39] (2019)Renewable energy technologies Cradle-to-gateSHDBThis paper compares renewable technologies from a supply chain perspective and identifies their hotspots.
Schlör et al. [40] (2017)Hydrogen production via alkaline water electrolysisCradle-to-gateSHDBThis paper investigates the social footprints and hotspots of supply chains of three hydrogen production supply chains in Europe (i.e., Germany, Austria, and Spain).
Lenzo et al. [41] (2017)Textile productionCradle-to-gateSHDBThis paper evaluates the social profile of a supply chain of a textile product based in Italy to identify hotspots.

2. Raw Rubber Production

2.1. Rubber Cultivation

The rubber plantation cycle considered herein spans over 25 years and is comprised of the nursery (one year), immature (five to seven years), and mature (over 18 years) stages [42,43]. During the nursery stage, seeds are collected from mature rubber trees and put in a nursery. At the early stage of growth, plants are bud grafted with scions of required genotypes. After the plants are mature enough to survive independently, they are transplanted into a field. Before planting rubber plants in the field, the land is cleared and prepared by removing obstructions and weeds. The soil is then tilled and fertilized to make it suitable for the growth of rubber trees [44].
Rubber trees typically require at least five years to enter the mature phase, where the rubber trees are ready for harvest. During the immature phase, the transplanted rubber plants are cared for to ensure healthy growth and development. Pruning may be necessary to ensure the tree’s proper shape and size. Rubber trees are susceptible to some pests and diseases. Application of insecticides or fungicides may be required to protect the tree from these threats [44].
Optimal growth and yields can be attained only by properly balancing the nutrients per need of the rubber plant. Most rubber-growing soils in Sri Lanka are deficient in nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg). However, these deficiencies could easily be remedied by applying inorganic fertilizers in the proper proportions and amounts. The most common fertilizers used are urea (for N), rock phosphate (for P), muriate of potash (MOP; for K), kieserite (KIE; for Mg), and dolomite (for Mg). These fertilizers are typically applied to the soil around the base of the tree [45].

2.2. Crepe Rubber Manufacture

First, rubber is tapped from the rubber tree and transported to the crepe rubber processing factory using bowsers. Before transporting, sodium sulfite is added as a preservative to the rubber to control fungal growth. At the factory, fresh latex is standardized, where its yellow pigments are fractionated, leaving the white fraction, which contains the majority of rubber particles in liquid form. Here, as per dry rubber content (DRC), sodium bisulfite and water are added. Yellow fraction comprises only ca. 10% of DRC [3]. The white fraction is then transferred to different containers while mixing with water, formic acid, and bleaching agents in the coagulating process. Then, the coagulum of the white fraction is cut into cube-like pieces and passed through a set of roller mills, a macerator, a diamond roller, and a smooth roller. The primary purpose of milling is to reduce the size of bulky coagulum pieces (with high water content) by pressing them into thin laces of rubber (containing less water). Thin laces are then draped over a drying tower and left for three to four days. Dried crepe laces are stacked, folded into 25 kg mats, and passed through a roller mill called a dry blanket mill, resulting in soft-edged rubber blankets. After the rubber blankets are cut to the customer’s desired size, they become known as blanket crepe rubber. The final step in the production of crepe rubber is the visual grading and packaging of the product for sale. The yellow fraction is further processed following the same procedure to obtain a lower-grade crepe rubber.

2.3. Concentrated Latex Manufacture

In latex collection and transportation to the factory, ammonia is added as a preservative to avert fungal growth in field latex. Upon arrival at the factory, a laboratory test measures the latex’s DRC and ammonia concentration. Then the latex is sifted through a 60-mesh sieve and collected in bulking tanks. The bulking tanks are filled with a mixture of tetramethyl thiuram disulfide (TMTD) and zinc oxide (ZnO) (often referred to as T.Z.), diammonium hydrogen phosphate (DAHP), and lauric soap. DAHP functions as a magnesium ion (Mg2+) remover, whereas others act as preservatives. Mg2+ elimination is crucial because the presence of Mg2+ encourages bacterial growth [3]. Decantation is performed to remove Mg2+ in the form of magnesium ammonium phosphate. The remaining field latex is then centrifuged in centrifuge separators. Field latex is separated into two segments at the separators: concentrated latex and skim latex, with %DRCs of ca. 60% and 3–6%, respectively. Acquired concentrated latex is preserved in steel tanks, with the ammonia concentration kept per customer specifications, i.e., high Ammonia (about 0.7%) or low Ammonia (about 0.2%), until dispatch. Skim latex is coagulated with sulfuric acid in a separate tank (the coagulation tank). After that, the coagulum is removed and pressed to get skim rubber laces. The laces are then air-dried before being mechanically pressed into rubber sheets (dry blanket milling). After that, the blankets are cut into tile-shaped segments and packaged as a skim crepe.

2.4. Ribbed Smoked Sheets Manufacture

Smallholders with less than five acres of rubber plantations manufacture RSS in Sri Lanka. RSS facility at this caliber can process up to 40 kg of rubber daily [3]. First, rubber trees are tapped to get fresh latex and handled at the mills. When latex arrives at the factory, it is coagulated by passing through a series of flat pans with water and formic acid. Then, the coagulum is milled using two hand-operated rollers, termed smooth and grooved rollers. The coagulum is passed through the smooth roller two to three times before being passed through the grooved roller once. Milled sheets are cleaned and placed in a shade for dripping before being smoke-dried. Smoke-drying involves hanging sheets in a smokehouse for three to five days. Finally, the dried sheets are weighed and transported to regional retail centers.

3. Methodology

3.1. Social Life Cycle Assessment

SLCA is a systematic approach to assess the social impacts of a product or system throughout its life cycle, from material extraction to final disposal or recycling [46]. SLCA is a relatively new tool for which a standardized methodology is yet to be proposed [47]. However, SLCA follows ISO14040/44 [48,49], the international standard for LCA. The first comprehensive framework for SLCA was published in 2009 [50], termed UNEP/SETAC Guidelines for Social Life Cycle Assessment of Products. Therein, five stakeholder categories (Workers, Local community, Society, Value chain actors, and Consumers) have been specified with six impact categories (i.e., Human rights, working conditions, Health & Safety, Development of the country, Socio-economic repercussion, and Governance) for developing social life cycle inventories [51]. To facilitate this process, a set of subcategories (e.g., Forced labor, Discrimination, etc.) were also defined at each stakeholder category and were set to assess using inventory indicators. A few years later, UNEP/SETAC Methodological Sheets for the Subcategories of SLCA were published to provide practical guidance for conducting SLCA case studies [52]. This document supplemented the above subcategories with inventory indicators and potential data sources. Various entities have developed SLCA databases and frameworks based on the above documents. For instance, NewEarth B released Social Hotspots Database [53] in 2013 to assess the social risks of product supply chains. A group of six companies with PRé Sustainability devised the framework of Product Social Impact Assessment in 2014 [54] to render practical guidance to performing SLCA of products at the corporate level; this framework has been updated at several stages ever since. The latest version of the UNEP/SETAC SLCA code of practice was released in 2020 (i.e., Guidelines for social life cycle assessment of Products and Organizations 2020) [49]. It provided extra guidance for the steps of SLCA from the lessons learned from the previous version. It touched on different areas of evaluating social issues of organizations and products, e.g., linking SLCA with the Sustainable Development Goals of the United Nations and Social Organizational life cycle assessment.
Figure 1 depicts an overview of the SLCA framework followed herein. Rectangles, Rectangles with rounded corners, and ovals represent the processes, inputs to specific processes, and outputs from processes, respectively. Section 3.2, Section 3.3, Section 3.4, Section 3.5, Section 3.6 and Section 3.7 provide detailed descriptions of this framework.

3.2. Goal and Scope Definition

We aim to analyze the social footprint of the three raw rubber supply chains, i.e., crepe rubber, concentrated latex, and RSS, seek avenues for improvements, and foresee their potential degrees of improvement when the upgrades are in place. The system boundary of the study is demarcated in Figure 2, in which the foreground system encapsulates the processes directly involved with raw rubber production on a cradle-to-gate basis (i.e., from rubber cultivation to manufacture). Such processes require site-specific data [55]. Meanwhile, items that are linked with background supply chains are indicated by shaded boxes, where sector- or country-level data (or generic data) are necessary (see inventory analysis section for more details on data collection) [55]. The functional unit for the study was set as delivering 1 tonne of product, i.e., white crepe, concentrated latex, and RSS. We follow the basic steps of ISO 14040/44 for the study [48,49].

3.3. Life Cycle Inventory Analysis

The second step involves collecting inventory data for background and foreground processes, which will later be used to model and evaluate potential social impacts at the impact assessment stage [56]. Initially, at this step, the system(s) being examined must be modeled using both site-specific (or foreground) data and generic data (or background data related to the supply chain). Foreground data refer to the data collected specifically for the analysed system [55]. Background data refer to the data used as inputs for the assessment that are not specific to the product being evaluated [56]. Accordingly, data were collected on the amounts of materials and energy inputs at the different stages of the life cycle within the system boundary, the economic sectors that those inputs belong to, regions where the materials and energy are sourced from, and the unit price of materials and energy [56].
Background information can be found in SLCA databases, and Social Hotspot Database (SHDB) was used in this regard [53]. SHDB provides three types of information; (1) supply chain composition, (2) labor intensity; and (3) social risks [56]. Provision No. 1 and 2 uses the Global Trade Analysis Project (GTAP) global economic equilibrium model version 9 [57]. Regarding No. 1, SHDB holds the trade flows between 57 economic sectors from 140 countries in 2011. Along with foreground data, the SHDB can compute trade flows of related sectors or regions. As for No. 2, SHDB determines the labor intensity by the “working hours per U.S. dollar of product output” for the year 2011 for each of the 57 economic sectors in each of the 140 countries, calculated by dividing GTAP data of total wage payments (U.S. dollars) per U.S. dollar of output by the sector/region average wage (U.S. dollars/hour) [58]. Regarding No. 3, SHDB holds the social risks information of over 160 social inventory indicators for 140 regions and 57 sectors and uses various sources for obtaining them (e.g., intergovernmental databases (e.g., ILO database), country statistics, literature, etc.). Risk information, for instance, the indicator: “percentage of the population living under USD 2 per day”, is used to attribute risk for the social subcategory: “Poverty” under the “Labor Rights and Decent Work” impact category (see impact assessment section for more details) [58].
Foreground data for the study was collected from different sources, as given below. Activity data on fertilizer use and unit prices in Sri Lanka were obtained from the Soils & Plant Nutrition Department of the Rubber Research Institute of Sri Lanka (RRISL). They were based on an annual mean over the plantation cycle of 25 years and productivity (on a dry basis) of 1 tonne/ha/year. Data on fungicides, herbicides, insecticide use, and diesel used for tillage were unavailable specifically for Sri Lanka. However, they could be considered common to any rubber-growing country. Therefore, those were gathered from literature (i.e., [42,43]) with prices from IndiaMART [59]. Material and energy inputs related to rubber manufacture were gathered from our previous research on crepe rubber [5,24], concentrated latex [1], and RSS manufacture [11]. Low-ammonia concentrated latex manufacturing was considered common in the Sri Lankan context [1].
Unit prices for material and energy inputs in rubber manufacture were taken from our recent publications [1,5,11,24]. Firewood and water required to manufacture crepe rubber and RSS are usually obtained within the estates. Hence no purchase cost has been considered. To be compatible with the GTAP model of SHDB, USD values gathered were standardized to match USD 2011 values using an online inflation calculator [60] (N.B. This tool is based on the consumer price index, which is a commonly used measure of inflation that tracks changes in the prices of goods and services over time). The regions from which the materials and energy were sourced were identified through RRISL, the Observatory of Economic Complexity (OEC) [61] and Volza databases [62]. The economic sectors corresponding to the inputs were determined using the GTAP manual [57]. Please refer to the Supplementary Material for more details on foreground data.
By integrating foreground data with background data from SHDB version 4 [53], we mapped three rubber supply chain models on SimaPro version 9.3 software [63].

3.4. Life Cycle Impact Assessment

This stage involved transforming inventory data collected in the preceding step into potential social impacts. The impact assessment phase in SHDB included 26 subcategories (e.g., Child labor, forced labor, etc.) aggregated into five impact categories, i.e., Labor rights & decent work, Human rights, Health & Safety, Governance, and Community. Around 160 social impact indicators were used to evaluate these subcategories, with some evaluated with a single indicator and others evaluated with multiple indicators [58]. Each indicator has four defined risk levels (very high, high, medium, and low) with a corresponding characterization factor (10, 5, 1, and 0.1, respectively) that reflects the relative probability of an adverse situation happening [58]. With the given value ‘1’, the medium risk level has been the basis for assigning relative probabilities to other levels. With Sima Pro v9.3, SHDB combined these characterization factors with inventory data acquired in the previous step to quantify the potential social impacts in Medium Risk Hours equivalent (Mrheq) [58]. Accordingly, the product of working hours and their risk levels provides the value of Mrheq. For instance, if child labor in sector A in country B is potentially at very high risk and the working hours to produce USD 1 of the final product is 1 h, the Mrheq of sector A becomes 10 × 1 = 10.
Ultimately, analyses provided three types of results, i.e., the social footprint, salient risks, and social hotspots. Social footprint refers to the overall impact of purchase supply chains, measured in Mrheq. This index highlights the supply chains that contribute the most to overall risks and the impact categories with the highest Mrheq values. Salient risks are the subcategories that account for a greater share of the overall risk [38]. Social hotspots are individual production activities or countries contributing significantly to the overall risk by impact category or subcategory [38].
The aggregation method, “Social hotspot 2019 Subcat & Cat Method w Damages”, was deployed to calculate the said indexes within SHDB [38,56].

3.5. Improvement Proposals

Firstly, we identified the most critically affected impact categories regarding social footprint results. Here, a contribution level of 20.0% was considered initially to identify the critically affected impact categories. Then, the highest contributing subcategories to those impact categories were identified. Thirdly, hotspot analyses were conducted to identify the sectors contributing significantly to the overall risk by the identified subcategories. Considering the level of contributions, a minimum level of 10.0% contribution level was kept initially to identify the most influential hotspots. Accordingly, alternative options were proposed to minimize the social risks.

3.6. Benefit Validation

Finally, the benefits of the alternative options proposed in the previous step were validated through a scenario analysis, where inventory was adjusted based on the nature of the alternative options before re-executing the impact assessment.

3.7. Interpretation

The final step of the framework was to analyze and interpret the outcomes of each stage by being interactive with them.

4. Results and Discussion

4.1. Social Footprints and Salient Risks in Supply Chains of Three Raw Rubber Types

Figure 3 illustrates the social footprints of three raw rubber types in Sri Lanka (in terms of medium risk hours equivalent (Mrheq) per 1 tonne of rubber product) as given by supply chain analyses. The social footprint of rubber cultivation has been higher than that of rubber manufacturing and transportation (which is negligibly handled by the factory of manufacturing) in all three cases. Comparably larger amounts of material use (especially chemicals and fertilizer) during rubber cultivation have been the roots of such results. Due to higher processing intensity, crepe rubber and concentrated latex supply chains showed larger Mrheq than RSS. Most critical social issues have been related to Governance for all supply chains. Further, Labor rights & decent work and Health & safety hold second and third places for all supply chains. ‘Human rights’ has been the least affected.
Table 2 encapsulates the social footprints of subcategories under each impact category in terms of Mrheq. Accordingly, the salient, highest risks are associated with Freedom of association & collective bargaining, followed by Corruption, Forced labor, Migrant labor, and the Legal system. ‘Unemployment’ poses the smallest social risk of all subcategories.
Figure 4, Figure 5 and Figure 6 illustrate the contribution of activities related to crepe rubber, concentrated latex, and RSS supply chains to the social risks in each subcategory. Supply chains associated with the rubber cultivation stage tend to dominate all graphs. For instance, MOP (K-fertilizer) and urea supply chains account for larger proportions of social risks in most subcategories. Notably, the MOP (K-fertilizer) supply chain overshadows the subcategories ‘Injuries & fatalities and ‘Unemployment’, while the urea supply chain does the same for the ‘Children out of the school’. However, all graphs recorded the largest contributor to ‘Access to drinking water’ as the herbicide supply chain.
Further, the DAHP supply chain contributes considerably to the same subcategory in the concentrated latex supply chain. The electricity supply chain shows a considerable contribution to risks at ‘Excessive working time’ and ‘Indigenous rights’ regarding the crepe rubber supply chain as the electricity demand remains larger than concentrated latex manufacture. Formic acid, the only purchase supply chain at RSS manufacture, contributes negligibly to all subcategories.

4.2. Improvement Proposals

Considering the impact categories having more than 20.0% of contribution to the social footprints in Figure 3, we focus on improving the social risks related to Governance, Labor rights & decent work. To do so, subcategories under the respective impact categories were investigated first.
We identified that a larger proportion of social issues related to Governance are from the subcategory Corruption for three rubber supply chains (i.e., crepe rubber: 56%; concentrated latex: 55%; RSS: 54%) (see Figure S1 in Supplementary Material). Similarly, the largest contribution to Labor rights & decent work was from the Freedom of association & collective bargaining (i.e., crepe rubber: 22%; concentrated latex: 21%: RSS ca. 22%) (see Figure S2 in the Supplementary Material).
Then, hotspot analyses were conducted to determine the contribution of each country and sector involved in the three production lines under the most influential subcategories identified, i.e., Corruption, and Freedom of association & collective bargaining.
Figure 7, Figure 8 and Figure 9 illustrate the results of hotspot analyses by supply chain (directly involving sectors with more than 3.0% of contribution to the social risks have been labeled for convenience). The sector named ‘Chemical, rubber, plastic products’ in Belarus poses the most significant social risk in all three supply chains under the two subcategories of the database, namely, Corruption and Freedom of association & collective bargaining. The sector mentioned above produces K-fertilizer required at the rubber cultivation stage (N.B., ca. 52% of K-fertilizer is imported from Belarus; see Table S1 in the Supplementary Material). Due to the importation of urea fertilizer from China (Ca. 42% of urea imported from China; see Table S1 in the Supplementary Material), herbicides from India (solely imported from India; see Table S1 in the Supplementary Material), and the social situation in Sri Lanka, the following three significant sectors contributing to social risks are the Chemical, rubber, plastic products in China, then the same in India and the Electricity sector in Sri Lanka, respectively. The Electricity sector in Belarus can be deemed an indirectly involved upstream sector that links with the Chemical, rubber, and plastic products sector in Belarus.
In the proposal for improvements, hotspot sectors contributing more than 10.0% were considered initially; therefore, the Chemical, rubber, and plastic product sector in Belarus had been the focus. SHDB ranks its inventory indicators for Corruption (i.e., Overall corruption) and Freedom of association & collective bargaining (i.e., Overall risk of freedom of association) in Belarus as Very high. Similarly, ‘Very high’ or ‘High’ risk levels have been assigned to the same inventory indicators of the other hotspot sectors (i.e., the Chemical, rubber, and plastic products sector in China and India and the Electricity sector in Sri Lanka) (see Table S11 in the Supplementary Material). However, relatively high K-fertilizer requirements per functional unit, unit price, and labor intensity (i.e., working hours per U.S. dollar of product output) of the sector tend to significantly augment the social risks associated with ‘Chemical, rubber, and plastic products sector in Belarus, along with its risk levels assigned to the inventory indicators under Corruption and Freedom of association & collective bargaining (i.e., Overall corruption and Overall risk of freedom of association).
Having 20% of K-fertilizer being imported from Lithuania (a relatively low social risk country where inventory indicators of Corruption and Freedom of association & collective bargaining are at ‘Medium’ risk levels) at present, there could be a possibility of increasing this amount up to 77% for avoiding the impact associated with Belarus. According to personal communication with officials of the Fertilizer Secretariat of Sri Lanka, the K-fertilizer has recently been imported from Israel, Jordan, Laos, Malaysia, Vietnam and Canada within the price range (in terms of CIF) of USD 850 to 950 per tonne. Therefore, this confirms the possibility of importing K-fertilizer from socially lower-risk countries (Countries where inventory indicators of Corruption and Freedom of association & collective bargaining are at ‘Medium’ or ‘Low’ risk levels) such as Canada, Israel, and Lithuania (see Table S11 in the Supplementary Material). We learned that the importation of fertilizer is currently being done considering the commercial value, availability of required amounts at the correct time, the trade balance between the relevant country, physical quality of material, credit facilities provided by the supplier, etc. However, no consideration has been given to social risks in the country of origin, particularly the sectors ‘Corruption and Freedom of association & collective bargaining’ revealed by the present study. Assuming equal amounts of K-fertilizer are imported from aforesaid countries with lower risks (i.e., Canada, Israel, and Lithuania) to avoid the social risks associated with the importation of the same from Belarus, the scenario analysis was implemented.

4.3. Benefit Validation

As per scenario analysis, overall social risks associated with Corruption in the supply chains can be reduced by ca. 36% if the importation of K-fertilizer shifted into low-risk countries. Similarly, it has impacted Freedom of association & collective bargaining by reducing ca. 25% of risks. As a result, social risks in two targeted impact categories, i.e., Governance and Labor rights & decent work, have remarkably been reduced by ca. 35–41% and ca. 17–20%, respectively (see Figure 10). Also, other impact categories showed notable improvements; for instance, the impact category ‘Health & safety’ has been improved by ca. 22%. However, this has had a relatively low impact on the impact category of ‘Human rights’.
This paper highlights the significance of considering the entire supply chain when performing SLCA. Neglecting to do so may result in overlooked impacts in various geographic regions where imports are involved. Moreover, it emphasizes the importance of refining the supply chain by eliminating identified hotspots to enhance the social sustainability of the product being manufactured.
Improvements were identified as promising and can further be magnified by addressing the next levels of hotspots identified herein. More specifically, the Chemical, rubber, and plastic product sector in China and the Electricity sector in Sri Lanka, which involves urea and electricity supply chains, respectively, may be the next touch points. Addressing the former issue may be achievable in the short term. However, resolving the latter may require more time and effort. In this regard, the Sri Lankan government should implement a comprehensive anti-corruption policy that outlines the laws, regulations, and punishments for acts of corruption. This policy must be widely disseminated and understood by all stakeholders in the energy sector so that corruption can effectively be deterred.
To improve the conditions of Freedom of association & collective bargaining in the energy sector in Sri Lanka, it is essential to ensure that workers’ rights are more respected than present. Moreover, the government should incentivize private companies to enter the energy sector fairly and transparently and comply with relevant labor laws [64,65]. Furthermore, the government should collaborate with private companies and trade unions to develop a skills training program for energy sector workers.
Under a situation where previous SLCA studies had overlooked the natural rubber industry, one of our previous studies (site-specific) on a Sri Lankan rubber estate revealed that the production of crepe rubber significantly impacted the workers’ social benefits, health and safety [14]. In contrast, using generic social data, this study unveiled a border spectrum of social risks concealed behind the far corners of the supply chains of raw rubber. This time also, we found that Health & safety is one of the critically affected impact categories that need to be thoroughly considered after Labor rights & decent work as the improvement continues. However, in our view, combining site-specific and generic analyses would uplift the clarity of these issues, thereby paving the way for the comprehensiveness of decision-making using SLCA.
The Methodology followed by SHDB calculates potential social risks based on characterization factors that reflect the relative probability of an adverse situation happening [58]. Therefore, the outcome may not reflect a realistic social profile. If indicators can be evaluated using site-specific data, aforesaid characterization factors could potentially be replaced by performance levels to reflect social performances that can represent a more realistic picture of social profiles. This could be an important area that requires further investigation by future research.
Managers may pay thorough attention to the hotpots identified herein in the first place and try to avoid those hotspots as much as possible and carry out importation from low-risk countries considering the trade-offs with economic and environmental aspects [66]. Once the hotspots identified herein are addressed, new ones may emerge. For instance, the possibility for Health & safety to become the most critically affected impact category is higher; hence new hotspots may emerge. Therefore, continuously addressing these issues—for example, following the Plan, Do, Check, and Act (PDCA) cycle—can significantly reduce social footprints. This type of effort can also help achieve net positive social impacts by creating social handprints [38,58]. Outcomes can be publicized in CSR reports and shared with peers to educate and encourage them to do the same.
Further, workshops can be organized in collaboration with LCA experts to educate the responsible personnel in the natural rubber industry on SLCA, as this analysis procedure requires extensive knowledge of SLCA itself. Once sufficient knowledge is acquired, factories can conduct their analyses independently. Till then, managers may have to consult LCA experts.
Since this study was based on generic social data from the SHDB (i.e., supply chain composition, labor intensity, and social risks) and the import ratios and unit prices that are prone to fluctuate, the potential social risks observed herein may differ from those associated with real-world processes for the time being [38]. This could be a major limitation of this study. Therefore, the supply chain may be analyzed using site-specific data to appraise social performances rather than potential social risks. Such an analysis could uncover more accurate and insightful information (such as positive and negative social impacts) about the supply chains considered in this study. However, it should be noted that this process may require a significant amount of data and effort. Following the footsteps of this study, natural rubber supply chains based in other countries may be evaluated by future research; such attempts may unveil not only the hotspots but also create avenues for collaborative benchmarking between different natural rubber supply chains to uplift their social performances and thereby to achieve social sustainability.

5. Conclusions

This paper could successfully unveil the underlying potential social risks of three main raw rubber supply chains, crepe rubber, concentrated latex, and RSS in Sri Lanka. The social footprint of rubber cultivation has been higher than that of rubber manufacturing and transportation due to the heavy material intensity at the cultivation stage. This paper also highlighted the social hotspots and potential degrees of improvement that can be achieved through refining those supply chains. More specifically, Governance Labor rights & decent work have been affected due to Corruption and Freedom of association and collective bargaining, mainly associated with Belarus and China’s Chemical, rubber, and plastic products sectors and the Electricity sector in Sri Lanka. Improvements were observed to be promising upon the addressing of those hotspots. For instance, if the importation of K-fertilizer shifted into countries with lower risks, overall social risks associated with Corruption and Freedom of association & collective bargaining in the supply chains could be reduced by ca. 36% and 25%, respectively. As a result, social risks in two targeted impact categories, i.e., Governance and Labor rights & decent work, were reduced by ca. 35–41% and ca. 17–20%, respectively. Therefore, relevant officials like managers may put their hands on urgently addressing these issues by avoiding the identified hotspots.
Further, they may continuously work toward reducing the social footprint of subjected rubber supply chains and, subsequently, using the positiveness in marketing approaches. The findings herein will help Sri Lanka compete in the sustainability-conscious-world rubber market, ultimately contributing to rebuilding its hard-hit economy. This paper vitalizes the supply chain-based analysis. Future research may apply such analyses to analyze natural rubber supply chains based in other countries to establish social sustainability in the natural rubber industry. The use of generic data on SHDB, import ratios, and unit prices prone to fluctuation may not reflect the real social profile of the subjected supply chains, remarking a significant drawback of the study. Therefore, future research may use site-specific data to acquire more realistic social profiles. Any industry may follow our methodical hierarchy to measure social sustainability and thereby give relevant refinements to assure the social well-being of the supply chain of interest.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/su151511623/s1, Table S1: Data related to Rubber cultivation (per field latex containing 1 tonne of dry rubber output). GTAP sector: Crops nec/LKA (Sri Lanka); Table S2: Data related to crepe rubber production (1 tonne of white-crepe rubber). GTAP sector: CRP/LKA (Sri Lanka); Table S3: Data related to concentrated latex production (per 1 tonne of concentrated latex). GTAP sector: CRP/LKA (Sri Lanka); Table S4: Data related to RSS production (per 1 tonne of RSS). GTAP sector: CRP/LKA (Sri Lanka); Table S5: Social risk contribution of the sectors involved in crepe rubber supply chain under Corruption. Cut-off mark: 1.0%. BLR: Belarus; CHN: China; LKA: Sri Lanka; IND: India; IDN: Indonesia; JOR: Jordan; Table S6: Social risk contribution of the sectors involved in crepe rubber supply chain under Freedom of association & collective. Cut-off mark: 1.0%. BLR: Belarus; CHN: China; LKA: Sri Lanka; IND: India; IDN: Indonesia; JOR: Jordan; Table S7: Social risk contribution of the sectors involved in concentrated latex supply chain under Corruption. Cut-off mark: 1.0%. BLR: Belarus; CHN: China; LKA: Sri Lanka; IND: India; IDN: Indonesia; JOR: Jordan; Table S8: Social risk contribution of the sectors involved in concentrated latex supply chain under Freedom of association & collective bargaining. Cut-off mark: 1.0%. BLR: Belarus; CHN: China; LKA: Sri Lanka; IND: India; IDN: Indonesia; JOR: Jordan; Table S9: Social risk contribution of the sectors involved in ribbed smoked sheets supply chain under Corruption. Cut-off mark: 1.0%. BLR: Belarus; CHN: China; LKA: Sri Lanka; IND: India; IDN: Indonesia; JOR: Jordan; Table S10: Social risk contribution of the sectors involved in ribbed smoked sheets supply chain under Freedom of association & collective bargaining. Cut-off mark: 1.0%. BLR: Belarus; CHN: China; LKA: Sri Lanka; IND: India; IDN: Indonesia; JOR: Jordan; Table S11: Risk levels of several countries related to the study as mentioned in the Social Hotspot Database. Indicator for Corruption: Overall corruption, Indicator for Freedom of association & collective bargaining: Overall risk of freedom of association; Figure S1: Contribution of each subcategory to the impact category, Governance. (a: crepe rubber; b: concentrated latex; c: ribbed smoked sheets); Figure S2: Contribution of each subcategory to the impact category, Labor rights & decent work’. (a: crepe rubber; b: concentrated latex; c: ribbed smoked sheets).

Author Contributions

Conceptualization, P.D., V.H.L.R. and N.G.; methodology, P.D. and V.H.L.R.; software, P.D.; validation, P.D. and V.H.L.R.; formal analysis, P.D.; investigation, P.D.; resources, I.D. and N.G.; data curation, P.D.; writing—original draft preparation, P.D.; writing—review & editing, V.H.L.R., I.D. and N.G.; visualization, P.D.; supervision, V.H.L.R., I.D. and N.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

We want to extend our sincere gratitude to Shobatake from TCO2 Co., Ltd. and the researchers (especially Sajeep Sankalpa and Rasika Hettiarachchi) and officials (especially Lakshman) from the Rubber Research Institute of Sri Lanka and factory employees (especially Ranil) for their invaluable assistance in helping us bring this project to fruition. Without their support, this work would not have been possible.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Dunuwila, P.; Rodrigo, V.H.L.; Goto, N. Improving Financial and Environmental Sustainability in Concentrated Latex Manufacture. J. Clean. Prod. 2020, 255, 120202. [Google Scholar] [CrossRef]
  2. IHS Markit. Rubber, Natural—Chemical Economics Handbook. Available online: https://www.ihs.com/products/natural-rubber-chemical-economics-handbook.html (accessed on 18 December 2017).
  3. Rubber Research Institute of Sri Lanka. Handbook of Rubber; Rubber Research Institute of Sri Lanka: Agalawatta, Sri Lanka, 2003.
  4. Jawjit, W.; Kroeze, C.; Rattanapan, S. Greenhouse Gas Emissions from Rubber Industry in Thailand. J. Clean. Prod. 2010, 18, 403–411. [Google Scholar] [CrossRef]
  5. Dunuwila, P.; Rodrigo, V.H.L.; Goto, N. Financial and Environmental Sustainability in Manufacturing of Crepe Rubber in Terms of Material Flow Analysis, Material Flow Cost Accounting and Life Cycle Assessment. J. Clean. Prod. 2018, 182, 587–599. [Google Scholar] [CrossRef]
  6. Tillekeratne, L.M.K.; Nugawela, A.; Seneviratne, W.M.G. Handbook of Rubber; Vishva Lekha Printers: Ratmalana, Sri Lanka, 2003. [Google Scholar]
  7. EMR. Market Research Reports|Strong Industry Analysis|Expert Market Research. Available online: https://www.expertmarketresearch.com/about-us (accessed on 15 March 2023).
  8. Bengtsen, P. Behind the Rubber Label; DanWatch: Copenhagen, Denmark, 2013. [Google Scholar]
  9. Sri Lanka Rubber Secretariat. Sri Lanka Rubber Industry Development Master Plan 2017–2026; Ministry of Plantation Industries of Sri lanka: Battaramulla, Sri Lanka, 2017. [Google Scholar]
  10. Jawjit, W.; Pavasant, P.; Kroeze, C. Evaluating Environmental Performance of Concentrated Latex Production in Thailand. J. Clean. Prod. 2015, 98, 84–91. [Google Scholar] [CrossRef]
  11. Dunuwila, P.; Rodrigo, V.H.L.; Goto, N. Assessing the Financial and Environmental Sustainability in Raw Rubber Processing; a Case Study with Ribbed Smoked Sheet Manufacture in Sri Lanka. Indones. J. Life Cycle Assess. Sustain. 2018, 2, 1–7. [Google Scholar] [CrossRef]
  12. Fagbemi, E.A.; Audu, M.; Ayeke, P.; Ohifuemen, A. Ribbed Smoked Rubber Sheet Production—Review. Ribbed Smoked Rubber Sheet Prod. Rev. 2018, 3, 38–41. [Google Scholar]
  13. Cecil, J.; Mitchell, P. Processing of Natural Rubber; FAO: Rome, Italy, 2003. [Google Scholar]
  14. Dunuwila, P.; Rodrigo, V.H.L.; Daigo, I.; Goto, N. Social Impact Improving Model Based on a Novel Social Life Cycle Assessment for Raw Rubber Production: A Case of a Sri Lankan Rubber Estate. J. Clean. Prod. 2022, 338, 130555. [Google Scholar] [CrossRef]
  15. UNESCAP. Country Study on Sri Lanka Using Global Value Chain Analysis: The Industrial Rubber and Electronic Products Sectors; United Nations: New York, NY, USA, 2011. [Google Scholar]
  16. Tillekeratne, L.M.K. Strategies to Curb Declining Rubber Production. Sunday Times Sri Lanka, 27 August 2017.
  17. Edirisinghe, J. Community Pressure and Environmental Compliance: Case of Rubber Processing in Sri Lanka. J. Environ. Prof. Sri Lanka 2013, 1, 14–23. [Google Scholar] [CrossRef]
  18. Leong, S.T.; Muttamara, S.; Laortanakul, P. Reutilization of Wastewater in a Rubber-Based Processing Factory: A Case Study in Southern Thailand. Resour. Conserv. Recycl. 2003, 37, 159–172. [Google Scholar] [CrossRef]
  19. Massoudinejad, M.; Mehdipour-Rabori, M.; Dehghani, M.H. Treatment of Natural Rubber Industry Wastewater through a Combination of Physicochemical and Ozonation Processes Citation: Massoudinejad M, Mehdipour-Rabori M, Dehghani MH. Treatment of Natural Rubber Industry Wastewater through a Combination of Physicoch. J. Adv. Environ. Health Res. 2015, 3, 242–249. [Google Scholar]
  20. Kumara, P.R.; Munasinghe, E.S.; Rodrigo, V.H.L.; Karunaratna, A.S. Carbon Footprint of Rubber/Sugarcane Intercropping System in Sri Lanka: A Case Study. Procedia Food Sci. 2016, 6, 298–302. [Google Scholar] [CrossRef] [Green Version]
  21. Tekasakul, P.; Tekasakul, S. Environmental Problems Related to Natural Rubber Production in Thailand. J. Aerosol Res. 2006, 21, 122–129. [Google Scholar]
  22. Tekasakul, S.; Tantichaowanan, M.; Otani, Y.; Kuruhongsa, P.; Tekasakul, P. Removal of Soot Particles in Rubber Smoking Chamber by Electrostatic Precipitator to Improve Rubber Sheet Color. Aerosol Air Qual. Res. 2006, 6, 1–14. [Google Scholar] [CrossRef] [Green Version]
  23. Rathnayake, W. Efficiency Study of a Single Day Smoke Dryer. Master’s Thesis, University of Moratuwa, Moratuwa, Sri Lanka, 2010. [Google Scholar]
  24. Dunuwila, P.; Rodrigo, V.H.L.; Goto, N. Sustainability of Natural Rubber Processing Can Be Improved: A Case Study with Crepe Rubber Manufacturing in Sri Lanka. Resour. Conserv. Recycl. 2018, 133, 417–427. [Google Scholar] [CrossRef]
  25. Pollok, L.; Spierling, S.; Endres, H.J.; Grote, U. Social Life Cycle Assessments: A Review on Past Development, Advances and Methodological Challenges. Sustainability 2021, 13, 10286. [Google Scholar] [CrossRef]
  26. Tragnone, B.M.; Serreli, M.; Arzoumanidis, I.; Pelino, C.A.; Petti, L. Using the Product Social Impact Life Cycle Assessment (PSILCA) Database for Product Comparison: Confetti Case Study. Int. J. Life Cycle Assess. 2023, 1, 1031–1053. [Google Scholar] [CrossRef]
  27. Arzoumanidis, I.; D’Eusanio, M. Tourism Sector: The Supply Chain Social Footprint of an Italian Accommodation Facility. Sustainability 2023, 15, 9793. [Google Scholar] [CrossRef]
  28. Sri Lanka Export Development Board. Industry Capability of Sri Lankan Rubber & Rubber Products Sector. Available online: https://www.srilankabusiness.com/rubber/about/industry-capability.html (accessed on 15 March 2023).
  29. Dunuwila, P. Integration of Process Analysis and Decision-Making Tools for the Sustainability Improvements in Raw Rubber Manufacture. Ph.D. Thesis, Toyohashi University of Technology, Toyohashi, Japan, 2019. [Google Scholar]
  30. Rubber Research Institute of Sri Lanka. Available online: http://www.rrisl.lk/sub_pags/statistics.html (accessed on 10 May 2016).
  31. Shi, Y.; Chen, X.; Jiang, T.; Jin, Q. Social Life Cycle Assessment of Lithium Iron Phosphate Battery Production in China, Japan and South Korea Based on External Supply Materials. Sustain. Prod. Consum. 2023, 35, 525–538. [Google Scholar] [CrossRef]
  32. Akhtar, M.S.; Khan, H.; Liu, J.J.; Na, J. Green Hydrogen and Sustainable Development—A Social LCA Perspective Highlighting Social Hotspots and Geopolitical Implications of the Future Hydrogen Economy. J. Clean. Prod. 2023, 395, 136438. [Google Scholar] [CrossRef]
  33. Iribarren, D.; Calvo-Serrano, R.; Martín-Gamboa, M.; Galán-Martín, Á.; Guillén-Gosálbez, G. Social Life Cycle Assessment of Green Methanol and Benchmarking against Conventional Fossil Methanol. Sci. Total Environ. 2022, 824, 153840. [Google Scholar] [CrossRef]
  34. Aranda, J.; Zambrana-Vásquez, D.; Del-Busto, F.; Círez, F. Social Impact Analysis of Products under a Holistic Approach: A Case Study in the Meat Product Supply Chain. Sustainability 2021, 13, 12163. [Google Scholar] [CrossRef]
  35. Martin, M.; Herlaar, S. Sustainable Production and Consumption Environmental and Social Performance of Valorizing Waste Wool for Sweater Production. Sustain. Prod. Consum. 2021, 25, 425–438. [Google Scholar] [CrossRef]
  36. Herrera Almanza, A.M.; Corona, B. Using Social Life Cycle Assessment to Analyze the Contribution of Products to the Sustainable Development Goals: A Case Study in the Textile Sector. Int. J. Life Cycle Assess. 2020, 25, 1833–1845. [Google Scholar] [CrossRef]
  37. Werker, J.; Wulf, C.; Zapp, P.; Schreiber, A.; Marx, J. Social LCA for Rare Earth NdFeB Permanent Magnets. Sustain. Prod. Consum. 2019, 19, 257–269. [Google Scholar] [CrossRef]
  38. Norris, C.B.; Norris, G.A.; Azuero, L.; Pflueger, J. Creating Social Handprints: Method and Case Study in the Electronic Computer Manufacturing Industry. Resources 2019, 8, 176. [Google Scholar] [CrossRef] [Green Version]
  39. Takeda, S.; Keeley, A.R.; Sakurai, S.; Managi, S.; Norris, C.B. Are Renewables as Friendly to Humans as to the Environment?: A Social Life Cycle Assessment of Renewable Electricity. Sustainability 2019, 11, 1370. [Google Scholar] [CrossRef] [Green Version]
  40. Schlör, H.; Jan, K.; Petra, Z.; Andrea, S.; Jürgen-Friedrich, H. The Social Footprint of Hydrogen Production-A Social Life Cycle Assessment (S-LCA) of Alkaline Water Electrolysis Selection and/or Peer-Review under Responsibility of ICAE. Energy Procedia 2017, 105, 3038–3044. [Google Scholar] [CrossRef]
  41. Lenzo, P.; Traverso, M.; Salomone, R.; Ioppolo, G. Social Life Cycle Assessment in the Textile Sector: An Italian Case Study. Sustainability 2017, 9, 2092. [Google Scholar] [CrossRef] [Green Version]
  42. Birnbach, M.; Lehmann, A.; Naranjo, E.; Finkbeiner, M. A Condom’s Footprint—Life Cycle Assessment of a Natural Rubber Condom. Int. J. Life Cycle Assess. 2020, 25, 964–979. [Google Scholar] [CrossRef] [Green Version]
  43. Jawjit, W.; Pavasant, P.; Kroeze, C.; Tuffey, J. Evaluation of the Potential Environmental Impacts of Condom Production in Thailand. J. Integr. Environ. Sci. 2021, 18, 89–114. [Google Scholar] [CrossRef]
  44. Rubber Research Institute of Sri Lanka. Production of Budded Plants; Rubber Research Institute of Sri Lanka: Agalawatta, Sri Lanka, 2016.
  45. Rubber Research Institute of Sri Lanka. Fertilizer for Rubber; Rubber Research Institute of Sri Lanka: Agalawatta, Sri Lanka, 2016.
  46. Ekener, E.; Hansson, J.; Gustavsson, M. Addressing Positive Impacts in Social LCA—Discussing Current and New Approaches Exemplified by the Case of Vehicle Fuels. Int. J. Life Cycle Assess. 2018, 23, 556–568. [Google Scholar] [CrossRef]
  47. Zheng, X.; Easa, S.M.; Ji, T.; Jiang, Z. Modeling Life-Cycle Social Assessment in Sustainable Pavement Management at Project Level. Int. J. Life Cycle Assess. 2020, 25, 1106–1118. [Google Scholar] [CrossRef]
  48. The International Organization for Standardization (ISO). International Standard ISO 14040; ISO: Geneva, Switzerland, 2006. [Google Scholar]
  49. Benoît Norris, C.; Traverso, M.; Neugebauer, S.; Ekener, E.; Schaubroeck, T.; Russo Garrido, S.; Berger, M.; Valdivia, S.; Lehmann, A.; Finkbeiner, M.; et al. Guidelines for Social Life Cycle Assessment of Products and Organisations 2020; UNEP: Nairobi, Kenya, 2020. [Google Scholar]
  50. Andrews, E.S.; Barthel, L.-P.; Tabea, B.; Benoît, C.; Ciroth, A.; Cucuzzella, C.; Gensch, C.-O.; Hébert, J.; Lesage, P.; Manhart, A.; et al. Guidelines for Social Life Cycle Assessment of Products; UNEP: Nairobi, Kenya, 2009. [Google Scholar]
  51. Hossain, M.U.; Poon, C.S.; Dong, Y.H.; Lo, I.M.C.; Cheng, J.C.P. Development of Social Sustainability Assessment Method and a Comparative Case Study on Assessing Recycled Construction Materials. Int. J. Life Cycle Assess. 2018, 23, 1654–1674. [Google Scholar] [CrossRef]
  52. Benoît-Norris, C.; Vickery-Niederman, G.; Valdivia, S.; Franze, J.; Traverso, M.; Ciroth, A.; Mazijn, B. Introducing the UNEP/SETAC Methodological Sheets for Subcategories of Social LCA. Int. J. Life Cycle Assess. 2011, 16, 682–690. [Google Scholar] [CrossRef]
  53. NewEarth B SHDB. Available online: http://www.socialhotspot.org/ (accessed on 31 October 2021).
  54. Saling, P.; Morris, D.; Florea, A.; Visser, D.; Morao, A.; Musoke-Flores, E.; Alvarado, C.; Rawat, I.; Schenker, U.; Goedkoop, M.; et al. Handbook for Product Social Impact Assessment; PRé Sustainability: Amersfoort, The Netherlands, 2020. [Google Scholar]
  55. Hannouf, M.; Assefa, G. Subcategory Assessment Method for Social Life Cycle Assessment: A Case Study of High-Density Polyethylene Production in Alberta, Canada. Int. J. Life Cycle Assess. 2018, 23, 116–132. [Google Scholar] [CrossRef]
  56. Santos, A.; Benoît Norris, C.; Barbosa-Póvoa, A.; Carvalho, A. Social Life Cycle Assessment of Pulp and Paper Production—A Portuguese Case Study. Comput. Aided Chem. Eng. 2020, 48, 15–20. [Google Scholar] [CrossRef]
  57. Center for Global Trade Analysis. Global Trade Analysis Project (GTAP). Available online: https://www.gtap.agecon.purdue.edu/ (accessed on 15 March 2023).
  58. Benoît Norris, C.; Norris, G. The Social Hotspots Database Context of the SHDB. In The Sustainability Practitioner’s Guide to Social Analysis and Assessment; Murray, J., McBain, D., Wiedmann, T., Eds.; Common Ground Publishing: Champaign, IL, USA, 2015. [Google Scholar]
  59. IndiaMART IndiaMART. Available online: https://www.indiamart.com/ (accessed on 16 March 2023).
  60. U.S. Bureau of Labor Statistics CPI Inflation Calculator. Available online: https://www.bls.gov/data/inflation_calculator.htm (accessed on 16 March 2023).
  61. Datawheel. The Observatory of Economic Complexity|OEC—The Observatory of Economic Complexity. Available online: https://oec.world/ (accessed on 16 March 2023).
  62. Volza Volza.Com—Global Export Import Trade Data of 209 Countries. Available online: https://www.volza.com/ (accessed on 16 March 2023).
  63. PRé Sustainability about SimaPro—SimaPro. Available online: https://simapro.com/about/ (accessed on 16 March 2023).
  64. Economynext Sri Lanka Opens Floodgates for Corruption in Power Sector: Harsha|EconomyNext. Available online: https://economynext.com/sri-lanka-opens-floodgates-for-corruption-in-power-sector-harsha-95565/ (accessed on 16 March 2023).
  65. ILO. 8.Freedom of Association and Collective Bargaining. Available online: https://www.ilo.org/global/topics/dw4sd/themes/freedom-of-association/lang--en/index.htm (accessed on 16 March 2023).
  66. Dunuwila, P.; Hamada, K.; Takeyama, K.; Panasiuk, D.; Hoshino, T.; Morimoto, S.; Tahara, K.; Daigo, I. Influence of Different Allocation Methods for Recycling and Dynamic Inventory on CO2 Savings and Payback Times of Light-Weighted Vehicles Computed under Product- and Fleet-Based Analyses: A Case of Internal Combustion Engine Vehicles. Sustainability 2021, 13, 13935. [Google Scholar] [CrossRef]
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Figure 1. The framework of the study. Rectangles with rounded corners and ovals represent the processes, inputs, and outputs, respectively. SHDB and RRISL refer to the Social Hotspot database and the Rubber research institute of Sri Lanka.
Figure 1. The framework of the study. Rectangles with rounded corners and ovals represent the processes, inputs, and outputs, respectively. SHDB and RRISL refer to the Social Hotspot database and the Rubber research institute of Sri Lanka.
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Figure 2. System boundary (Cradle-to-gate) of the study. Shaded boxes demarcate background processes. LDPE refers to low-density polyethylene. The main countries involved in the raw rubber supply chain based in Sri Lanka are mentioned within parentheses (For more details, please refer to Tables S1–S4 in the Supplementary Material).
Figure 2. System boundary (Cradle-to-gate) of the study. Shaded boxes demarcate background processes. LDPE refers to low-density polyethylene. The main countries involved in the raw rubber supply chain based in Sri Lanka are mentioned within parentheses (For more details, please refer to Tables S1–S4 in the Supplementary Material).
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Figure 3. Social footprints of three raw rubber types per 1 tonne of product basis in terms of medium risk hours equivalent (Mrheq). Contributions of respective impact categories to the social footprints of respective products are indicated within parentheses as percentages (%). RSS refers to ribbed smoked sheets.
Figure 3. Social footprints of three raw rubber types per 1 tonne of product basis in terms of medium risk hours equivalent (Mrheq). Contributions of respective impact categories to the social footprints of respective products are indicated within parentheses as percentages (%). RSS refers to ribbed smoked sheets.
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Figure 4. Contribution of crepe-rubber supply chain activities at every subcategory. LDPE, MOP, and KIE refer to low-density polyethylene, muriate of potash, and kieserite.
Figure 4. Contribution of crepe-rubber supply chain activities at every subcategory. LDPE, MOP, and KIE refer to low-density polyethylene, muriate of potash, and kieserite.
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Figure 5. Contribution of activities related to concentrated latex rubber supply chain at every subcategory. DAHP, TZ, TMTD, MOP, and KIE refer to diammonium hydrogen phosphate, a mixture of tetramethyl thiuram disulfide (TMTD) and zinc oxide (ZnO), tetramethyl thiuram disulfide, muriate of potash, and kieserite, respectively.
Figure 5. Contribution of activities related to concentrated latex rubber supply chain at every subcategory. DAHP, TZ, TMTD, MOP, and KIE refer to diammonium hydrogen phosphate, a mixture of tetramethyl thiuram disulfide (TMTD) and zinc oxide (ZnO), tetramethyl thiuram disulfide, muriate of potash, and kieserite, respectively.
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Figure 6. Contribution of ribbed smoked sheets rubber supply chain activities at every subcategory. MOP and KIE refer to the muriate of potash, and kieserite, respectively.
Figure 6. Contribution of ribbed smoked sheets rubber supply chain activities at every subcategory. MOP and KIE refer to the muriate of potash, and kieserite, respectively.
Sustainability 15 11623 g006
Sustainability 15 11623 g007 550
Figure 7. Hotspots analysis of crepe rubber supply chain ((a): Corruption; (b): Freedom of association & collective bargaining). Sectors with more than 3.0% contribution are labeled. Red text: x ≥ 10.0%; orange text: 10.0% > x ≥ 5.0%; green text: 5.0% > x ≥ 3.0%. Grey text signifies indirectly involved sectors. Sectors with less than 3.0% contribution are signified by bluish portions. For more details on hotpot sectors, see Tables S5 and S6 in the Supplementary Material. BLR, CHN, LKA, and IND refer to Belarus, China, Sri Lanka, and India.
Figure 7. Hotspots analysis of crepe rubber supply chain ((a): Corruption; (b): Freedom of association & collective bargaining). Sectors with more than 3.0% contribution are labeled. Red text: x ≥ 10.0%; orange text: 10.0% > x ≥ 5.0%; green text: 5.0% > x ≥ 3.0%. Grey text signifies indirectly involved sectors. Sectors with less than 3.0% contribution are signified by bluish portions. For more details on hotpot sectors, see Tables S5 and S6 in the Supplementary Material. BLR, CHN, LKA, and IND refer to Belarus, China, Sri Lanka, and India.
Sustainability 15 11623 g007
Sustainability 15 11623 g008 550
Figure 8. Hotspots analysis of concentrated latex supply chain ((a): Corruption; (b): Freedom of association & collective bargaining). Sectors with more than 3.0% contribution are labeled. Red text: x ≥ 10.0%; orange text: 10.0% > x ≥ 5.0%; green text: 5.0% > x ≥ 3.0%. Grey text signifies indirectly involved sectors. Sectors with less than 3.0% contribution are signified by bluish portions. For more details on hotpot sectors, see Tables S7 and S8 in the Supplementary Material. BLR, CHN, LKA, and IND refer to Belarus, China, Sri Lanka, and India.
Figure 8. Hotspots analysis of concentrated latex supply chain ((a): Corruption; (b): Freedom of association & collective bargaining). Sectors with more than 3.0% contribution are labeled. Red text: x ≥ 10.0%; orange text: 10.0% > x ≥ 5.0%; green text: 5.0% > x ≥ 3.0%. Grey text signifies indirectly involved sectors. Sectors with less than 3.0% contribution are signified by bluish portions. For more details on hotpot sectors, see Tables S7 and S8 in the Supplementary Material. BLR, CHN, LKA, and IND refer to Belarus, China, Sri Lanka, and India.
Sustainability 15 11623 g008
Sustainability 15 11623 g009 550
Figure 9. Hotspots analysis of RSS supply chain ((a): Corruption; (b): Freedom of association & collective bargaining). Sectors with more than 3.0% contribution are labeled. Red text: x ≥ 10.0%; orange text: 10.0% > x ≥ 5.0%; green text: 5.0% > x ≥ 3.0%. Grey text signifies indirectly involved sectors. Sectors with less than 3.0% contribution are signified by bluish portions. For more details on hotpot sectors, see Tables S9 and S10 in the Supplementary Material. BLR, CHN, LKA, and IND refer to Belarus, China, Sri Lanka, and India.
Figure 9. Hotspots analysis of RSS supply chain ((a): Corruption; (b): Freedom of association & collective bargaining). Sectors with more than 3.0% contribution are labeled. Red text: x ≥ 10.0%; orange text: 10.0% > x ≥ 5.0%; green text: 5.0% > x ≥ 3.0%. Grey text signifies indirectly involved sectors. Sectors with less than 3.0% contribution are signified by bluish portions. For more details on hotpot sectors, see Tables S9 and S10 in the Supplementary Material. BLR, CHN, LKA, and IND refer to Belarus, China, Sri Lanka, and India.
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Sustainability 15 11623 g010 550
Figure 10. Reduction potentials of social risks in the supply chain ((a): crepe rubber; (b): concentrated latex; (c): ribbed smoked sheets) by importing K-fertilizer from countries with lower risks (i.e., Canada, Israel, Lithuania).
Figure 10. Reduction potentials of social risks in the supply chain ((a): crepe rubber; (b): concentrated latex; (c): ribbed smoked sheets) by importing K-fertilizer from countries with lower risks (i.e., Canada, Israel, Lithuania).
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Table
Table 2. Social footprints of subcategories of each impact category under three rubber supply chains. CL and RSS refer to concentrated latex and ribbed smoked sheets, respectively. Values are given in Mrheq per 1 tonne of product basis with the percentage of contribution to the total in parenthesis.
Table 2. Social footprints of subcategories of each impact category under three rubber supply chains. CL and RSS refer to concentrated latex and ribbed smoked sheets, respectively. Values are given in Mrheq per 1 tonne of product basis with the percentage of contribution to the total in parenthesis.
Impact CategorySubcategoryCrepe RubberCLRSS
Labor rights and decent workWage262.9 (2.8)253.1 (2.7)205.2 (2.8)
Poverty417.3 (4.4)454.3 (4.8)317.7 (4.4)
Child Labor446.6 (4.7)433.3 (4.6)319.3 (4.4)
Forced Labor614.9 (6.5)655.6 (6.9)498.4 (6.8)
Excessive WkTime206.6 (2.2)185.4 (2.0)140.3 (1.9)
Freedom of Assoc1027.1 (10.8)990.9 (10.4)780.0 (10.7)
Migrant Labor611.0 (6.4)645.2 (6.8)487.1 (6.7)
Social Benefits326.0 (3.4)307.2 (3.2)225.9 (3.1)
Labor Laws/Convs215.5 (2.3)197.0 (2.1)163.0 (2.2)
Discrimination564.8 (5.9)554.1 (5.8)439.0 (6.0)
Unemployment31.9 (0.3)31.6 (0.3)27.2 (0.4)
Health & safetyOcc Tox & Haz572.8 (6.0)555.1 (5.9)448.1 (6.2)
Injuries & Fatalities130.0 (1.4)131.5 (1.4)111.9 (1.5)
Human rightsIndigenous Rights156.6 (1.6)164.6 (1.7)117.7 (1.6)
Gender Equity283.6 (3.0)301.7 (3.2)221.1 (3.1)
High Conflict Zones461.2 (4.8)493.0 (5.2)356.2 (4.9)
Non-Communicable Diseases188.2 (2.0)153.0 (1.6)123.8 (1.7)
Communicable Diseases215.7 (2.3)226.4 (2.4)164.7 (2.3)
GovernanceLegal System609.7 (6.4)598.6 (6.3)481.5 (6.6)
Corruption767.0 (8.1)718.6 (7.6)575.5 (7.9)
CommunityAccess to Drinking Water128.0 (1.3)152.5 (1.6)94.3 (1.3)
Access to Sanitation224.2 (2.4)240.6 (2.5)170.8 (2.3)
Children out of School270.3 (2.8)256.3 (2.7)214.8 (2.9)
Access to Hospital Beds278.3 (2.9)296.1 (3.1)216.0 (3.0)
Smallholder v Commercial Farms502.8 (5.3)487.5 (5.1)382.6 (5.3)
Total 9513.09483.17281.9
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Dunuwila, P.; Rodrigo, V.H.L.; Daigo, I.; Goto, N. Social Sustainability of Raw Rubber Production: A Supply Chain Analysis under Sri Lankan Scenario. Sustainability 2023, 15, 11623. https://doi.org/10.3390/su151511623

AMA Style

Dunuwila P, Rodrigo VHL, Daigo I, Goto N. Social Sustainability of Raw Rubber Production: A Supply Chain Analysis under Sri Lankan Scenario. Sustainability. 2023; 15(15):11623. https://doi.org/10.3390/su151511623

Chicago/Turabian Style

Dunuwila, Pasan, V. H. L. Rodrigo, Ichiro Daigo, and Naohiro Goto. 2023. "Social Sustainability of Raw Rubber Production: A Supply Chain Analysis under Sri Lankan Scenario" Sustainability 15, no. 15: 11623. https://doi.org/10.3390/su151511623

APA Style

Dunuwila, P., Rodrigo, V. H. L., Daigo, I., & Goto, N. (2023). Social Sustainability of Raw Rubber Production: A Supply Chain Analysis under Sri Lankan Scenario. Sustainability, 15(15), 11623. https://doi.org/10.3390/su151511623

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