App. Envi. Res.

38 (1): 11-18

Applied Environmental Research

Journal homepage : http://www.tci-thaijo.org/index.php/aer

Greenhouse Gas Emission in Jewelry Industry: A Case Study of Silver Flat Ring

Parnuwat Usapein1 , Chantra Tongcumpou2,*

1
Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University,
Phayathai Road, Patumwan, Bangkok 10330, Thailand
2
Environmental Research Institute, Chulalongkorn University, Thailand
*
Corresponding author: Email: Chantra.T@gmail.com

Article History
Submitted: 13 October 2015/ Accepted: 25 January 2016/ Published online: 25 February 2016

Abstract
This paper describes an assessment of the carbon footprint (CF) of a silver ring, together with
an attempt to measure material and energy consumption. The boundary of analyzing CF was
defined as Business to Business (B2B). All primary data were obtained from a survey of the case
study factory. Acquisition of raw material (silver) was the main GHG contribution to the overall
CF and was thus considered as a CF hotspot. Acquisition accounted for 0.9740 kg CO 2 e or
94.44% of total emissions, followed by production processes (0.0573 kg CO 2 e) and tran-
sportation (0.002 kg CO 2 e). The total CF amounted to 1.03 kg CO 2 e per silver ring product. To
reduce the CF, it is suggested that choosing low GHG production processes could result in
significant reduction in total CF. In addition, the study proposes options for recycling waste and
using high performance electronic equipment.

Keywords: Carbon footprint product; Silver flat ring; Jewelry industry

Introduction billion, with more than 1.3 million employed in

Thailand’ s gem and jewelry industry is the industry, representing 3.31 percent of the
widely considered one of the greatest potential country’s total workforce [2]. However, the
markets in the world, highly regarded both as a slowdown in the economies of key trading
source of a wide variety of gemstones, and for partners, together with volatility of major cur-
its highly skilled artisans [1]. The gem and je- rencies have led to adverse impacts on the
welry industry is important to the country’s competitiveness of the sector. In a highly com-
economic development; trade in gems and je- petitive sector, environmental issues have emerged
welry products was ranked fourth among Thai- as factors for selecting products, especially the
land’s exports in 2011, valued at US$ 32.95 impact of jewelry products on climate change.
12 App. Envi. Res. 38 (1): 11-18

Over the past century, the planet’s average in vestors because CFP can serve as a proxy for
temperature has risen by 0.6 C and is forecast investment risk [10]. In addition, the goal of re-
to rise by 1.1 to 6.4 C over the next hundred ducing CFP can stimulate innovation and drive
years [3]. Many countries have already felt the progress towards a low carbon society [11]. In
impacts; from heat waves and droughts, floods, the jewelry industry, CPF is used not only as an
extreme weather events, melting glaciers and indicator to determine the amount of GHG
rising sea levels. Anthropogenic causes are re- emissions throughout the product life cycle, but
cognized as one of the major contributions to also as a benchmark for improving production
climate change [4]. processes. Although there are many studies of
As a result of multilateral agreements such carbon footprint of diverse products such as
as the Kyoto Protocol and the Copenhagen grapes [12], plastic products [13] and beef pro-
Protocol, most UN Member States, including ducts [14], there have been few studies to quan-
Thailand, have agreed to force their industries tify CFPs in the gem and jewelry industry.
to take actions to mitigate greenhouse gas ( GHG) To fill this gap in the data, the sliver ring
emissions [ 5]. Therefore, Thailand’s Ministry was selected for study. The study objectives
of Industry has promoted its eco-industry po- were to (1) create an inventory of GHG emis-
licy to support sustainable economic growth in sions for the process of producing a sliver ring;
parallel with environmental conservation [ 6] . (2) estimate GHG emissions from silver ring
In regard to trade, some additional require- production; and (3) propose options for reduc-
ments have been specified to facilitate exports ing GHG emissions from silver ring production.
to developed countries, including product car-
bon footprints, ISO 14000, carbon credits, life Methodology
cycle assessment, or green label. 1) Site study and data collection
Mining for diamonds, gold, silver, and other The survey was conducted in 2015. The sil-
precious metals can result in water pollution, ver ring production process, packaging pro-
soil erosion, and greenhouse gas emissions [7]. cess, and waste treatment facilities at the plant
Glaister and Mudd ( 2010) reported that the were surveyed . The data obtained included the
critical sustainability issue concerning raw ma- amount of raw material, energy consumption,
terials for the jewelry industry ( e.g. platinum) and quantity of waste; the data were collated in
was not the size of the resource, but was related a spreadsheet.
to environmental costs including greenhouse gas
emissions. In future, environmental footprint 2) Goal and scope
and social concerns will carry an increasingly The objective of this study was to calculate
important influence on both demand and the the carbon dioxide emission throughout the life
ability of mines to increase their capacity. Con- cycle of silver ring production, from raw mate-
sumers can raise awareness of such issues by rial acquisition, production processes, transpor-
supporting eco-friendly jewelers, and by selecting tation, and waste treatment.
only products carrying ‘green certification’ [8].
The term ‘Carbon Footprint Product’ (CFP) 2.1) Functional unit
refers to the mass of CO 2 equivalent emitted The definition of the functional unit for
throughout the life-cycle of a product [9, 10]. It estimating CFP was based on 1 silver band.
has emerged as a useful indicator for consu- The data on energy consumption, chemical
mers, policy makers, governments and especially reagents, pollutant emissions and materials are
based on this functional unit.
App. Envi. Res. 38 (1): 11-18 13

considers greenhouse gas emission from raw

2.2) System boundary material extraction throughout the production
In this study, the boundary for analyzing the process until the point where the product was de-
carbon footprint of the product was defined as livered to a third party. It excludes final product
B2B, as shown in Figure 1. The B2B life cycle distribution, consumer use, and disposal [15].

Figure 1 Boundary system for estimating GHG emissions in this study

14 App. Envi. Res. 38 (1): 11-18

3) GHG Life cycle inventory analysis The methodology of estimating GHG emis-
All raw material used in the production pro- sions through the product ’s life cycle is based
cess was collected at the factory. Data from the on Equation (1).
Thai database e.g. TGO guidelines and Thai Total GHG emissions = GHGRaw material extraction +
National LCI database were used as first prio- GHGT ransportation +
rity when available. In case data were not avai- GHGProduction …..(1)
lable in the Thai database, Ecoinvent v2.0 was GHGRaw material extraction refers to GHG emis-
used instead [16]. Inventory data for estimating sions from raw material extraction, normally cal-
greenhouse gas emission of a single silver band culated by multiplying the amount of raw mate-
are shown in Table 1. rial (kg) by the emission factor (kgCO2/kg raw ma-
terial)
Table 1 Inventory data for producing 1 silver band GHGT ransportation refers to GHG emissions ge-
Process Quantity Unit nerated during transportation of raw materials
Candle mold from site to factory .In this study, however, these
Material/Energy consumption data could not be collected .Therefore, the de-
Silicone 3.75E- 05 kg fault values were used instead in accordance
Electricity 1.25E- 04 kWh
with the suggestion from [18].
Brass 9.00E- 03 kg
Pink wax 3.93E- 07 kg GHGProduction refers to GHG emissions gene-
Candle core 3.67E- 04 kg rated from the production process; mainly from
Electricity 3.94E- 02 kWh combustion processes or chemical reactions. In
Casting process addition, it includes energy usage during the pro-
Material/Energy consumption cess, e.g., electricity and steam.
Plaster 3.33E- 02 kg
Silver 9.34E- 03 kg 5) Interpretation
Alloy 4.92E- 04 kg
The result of calculating GHG emission entire
Additional 9.40E- 04 kg
life cycle product was evaluated and analyzed.
Stopper
wax 1.18E- 05 kg
Seal 1.25E- 03 kg The hotspot of GHG emissions was identified du-
Sulfamic acid 8.33E- 04 kg ring this step, and options proposed for reducing
Electricity 3.50E- 02 kWh GHG emissions.
Sandblast 6.88E- 05 kg
Polishing process Result and discussion
Material/Energy consumption 1) GHG emissions of 1 silver band
Brush 1.04E- 05 kg The result of calculating the carbon footprint
Packaging 1.82E- 02 kg
of production of a silver band can be divided into
Electricity 1.47E- 03 kWh
3 parts: raw material acquisition; transportation;
and production process, as shown in Table 2.
4) Calculation of GHG emissions for silver ring
The CF calculation shows that the raw mate-
GHG emissions will be expressed in terms of
rial acquisition stage makes the highest GHG con-
the mass of carbon dioxide equivalent (CO 2 e).
tribution (0.9740 kg CO 2 e or 94.44%) followed
The Global Warming Potential (GWP 100) for
by production (0.0573 kg CO 2 e) and transport-
six greenhouse gases (i.e., CO2, CH4, N2O, HFCs,
tation (0.002 kg CO 2 e). In conclusion, the total
PFCs, and SF6) are in accordance with the latest
CD of silver rind product is 1.03 kg CO 2 e per
document available from the Intergovernmental
silver band.
Panel on Climate Change or the IPCC [17].
App. Envi. Res. 38 (1): 11-18 15

The hotspot of CF in this study was iden- raw materials should be sought . Silver is nor-
tified as shown in Figure 2 .It can be identified mally produced as a by- product of the smelting
that the process of silver production was the of other metals such as gold, lead and Copper.
hotspot of GHG emissions for producing a silver Emissions vary for each process, as shown in
ring .GHG emissions from this phase was 0 .93 Table 3.
kg CO 2 e per silver band, or 90.19 % of the total Choosing low GHG emission sources of silver
CF. Electricity in process production makes the can reduce the total CF for production of a sil-
second highest contribution, with 0 .0565 kg CO2e ver ring. This will raise awareness of climate
per silver band, or 5.45 %of the total CF. change issues among both silver producers and
ring manufacturers. Manufacturers of silver rings
2) Proposed options for reducing CFP may face pressure from consumers who need
2.1) Selecting low GHG emission of silver
low carbon products; manufacturers can res-
The results indicate that raw material extrac-
pond by using low-emission processes as sug-
tion (silver) makes the most important contri-
bution to the CF of production of a silver ring. gested herein.
Therefore, alternative low-emission sources of

Table 2 CF calculation of silver ring product

Life cycle GHG emission of raw GHG emission of Total Percentage
phase material acquisition transportation (kg CO2 eq)
from raw maerial and (Includes raw material
energy (kg CO2 eq) and energy; kg CO2 eq)
Raw material
0.9740 0.0023 0.9763 94.44
acquisition
Production
0.0573 0.0001 0.0574 5.56
process
Total 1.03 0.002 1.03 100

Figure 2 Contribution to GHG emissions from production of one silver band

16 App. Envi. Res. 38 (1): 11-18

Table 3 GHG emissions for extraction of silver via different processes

Process GHG emission factor
(kg CO2 /kg)
Silver, from combined gold- silver production, at refinery/PE S 110.57
Silver, from combined metal production, at beneficiation/SE S 61.74
Silver, from copper production, at refinery/GLO S 20.06
Silver, from lead production, at refinery/GLO S 55.19
Silver, secondary, at precious metal refinery/SE S 14.50
Source: [19]

2.2) Recycling process materials (plaster and were calculated successively. One silver band
candle molds) was used as the functional unit (FU). The re-
Recycling of material using in the produc- sults indicate that the raw material acquisition
tion process is another important option for re- can be regarded as a hotspot of GHG emissions
ducing GHG emission. This approach will reduce over the production life cycle. Total emissions
emissions and also reduce production costs. from this stage are estimated at 0.9763 kgCO 2 e,
Used plaster from the casting process can be representing 94.44% of total CFP. The emis-
reused; however, only about 20% can be re- sions generated from the production process it-
used due to damage and deterioration of the self amounted to only 0 .0573 kgCO 2 e, represent-
material’s properties. ing just 5.56% of total CFP.
Candle molds can be melted and reused to The study’s results indicate that selection of
produce new molds. However, only about 40% silver produced from low-emission sources should
of candle molds can be recycled due to damage. be prioritized . This can considerably reduce the
total CFP because of its high share of total emis-
2.3) Using high performance energy-saving sions over the life cycle. Other options for re-
electrical equipment ducing waste and energy consumption should
Electricity consumption is the second most also be explored, including: (1) recycling plas-
important contributor to the total CF of silver ter and candle molds as raw materials for the
ring production .The survey found that the fac- productoin process; and (2) using high perfor-
tory still uses low-efficiency magnetic ballasts mance, energy-efficient electrical equipment.
for lighting, rather than modern electronic bal- These options can reduce emissions and gene-
lasts .Electronic ballasts can reduce energy loss rate significant cost reductions for the jewelry
by approximately 10- 12 watts per bulb com- industry.
pared to magnetic ballasts [20]. This option can Although the majority of data used in this
reduce both GHG emissions and reduce pro- study were gathered from on- site factory, some
duction costs for the factory. were also gathered from secondary data from
previous studies, and using standard assump-
Conclusions tions for parameters such as distance of trans-
This study the carbon footprint of silver flat portation between producers and customers.
ring was evaluated. Based on the study’s de- These assumptions can affect the accuracy of
fined system boundaries, GHG emission gene- the CFP assessment . Future investigation should
rated from raw material acquisition, production investigate and corroborate such assumptions
process, transportation, and waste treatment using empirical data. Nevertheless, the results
App. Envi. Res. 38 (1): 11-18 17

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