The textile industry has one of the largest environmental impacts in the world. Due to ecological concerns, it is necessary to find the ways to reduce these environmental impacts. This is true with denim as it is made of cotton, which, in most cases, is a very polluting crop, dyed with indigo, a dye with a very damaging degree of fixation which initiates huge ecological problems. Life cycle assessment provides data from every stage of a product's life, from the cradle to the grave (i.e., from raw material extraction through cultivation, manufacturing, distribution, use, repair and maintenance, and disposal or recycling). These data can be considered as one of the first ways to reduce environmental impacts. Therefore, the life cycle assessment of denim and how it affects the ecosystem is important to know. This article will provide some ideas about the life cycle assessment and its importance, life cycle of denim, life cycle assessment tool, phases of the life cycle assessment and a life cycle assessment of denim with actual data.
Key words: Climate change, Water consumption, Eutrophication, Abiotic depletion, Life cycle assessment.
Even before the industrial revolution the sustainable fashion got started, when the people were conservative of recourse together with the cost and labor was taken to satisfy the essential basic things in life . Nature (fibers, colorants) are the raw materials for textile fabrics and it requires a long time to transfer into a garment. It was only affordable to wealthy due to huge amount spent for requirement and cost of the labor. The textile industry to grew quickly because of the synthetic dyes, synthetic fibers and other new products of the industrial revolution. During the mid-ninetieth centenary, the products of textile were reasonably priced to all classes of people and apparel was more plentiful and easily manageable leading to the development of consumerism. Hence, the rate of production of textile and garments increased due to the purchasing capacity of the consumer. Factors like consumer awareness, government intervention by legislation, and diversification of textile production aided the growth of textile and apparel industry. Due to the advancement in information technology, consumers have been able to access data showing the impact of this industry. Hence consumers forced the manufacturers and retailers to take necessary action to reduce the environmental, economic and social impact of the various processes of the textile value chain.
The environmental effects of the production of textiles were not considered as they disposed chemicals in nearby rivers and watersheds by the textile manufacturers during the industrial revolution, resulting in emergence of environmentalism and social consciousness. New ways of disposing, recycling, and reusing their clothes were considered by the consumers. Production processes of clothes and the impact of this process had on the environment were considered, thereby developing a conscientious lifestyle by the consumers. Responding to it, eco-labeling began to stand up as a way of updating consumers that companies caution with a sustainable viewpoint. As a response to conscientious consumerism, eco-labeling began to arise as a way of informing consumers that companies care and are on board with a sustainable viewpoint. In the past decade the environmental issues (i.e. global warming) and its impact in all fields came into focus by the society globally. Henceforth, rather than disposables, manufacturers have had to develop sustainable products. The life cycle assessment of denim jeans which is known to be a significant part of the fashion industry due to its popularity is focused in this article. USA consumers typically own seven pairs of denim at the same time according to the Cotton Inc. report . The detailed analysis of a product and the entire lifespan of products from fibers to the retailing of denim is described in the Life Cycle Assessment (LCA). The production of raw materials, the manufacturing process of denim garments, logistics, its use, and ending with the denim's reuse, recycling and disposal are therefore encompassed by it. The consumer behavior is considered in the product's use phase and end-of-life disposal phase; however critical stages in a product's life cycle. There is an impact on the environment such as energy and water usage, CO2 emission and waste during the manufacturing phase of denim [3–7].
Stages of LCA
Generally, the LCA can be divided into four stages. The aim of the study and description of the product (denim) to be assessed are included in the first stage. From the acquisition of raw materials to the development of the final product information from all the process of product life cycle are collected and processed in the second stage of inventory. Energy consumption, raw material requirements, environmental emissions and discharges relating to the product can be figured and presented as these data can be developed to calculate the discharge from the processes of the product's life cycle during this stage. The “impact assessment stage” which is the third stage is in which the inventory data are translated into their effects of human health, ecological health and resource depletion. Based on analysis of the impact assessment results, “recommendations” is the last stage of this process. The environmental impact of any product is accessed by the very important procedure known as LCA. Therefore, the most polluting stages of the process can easily be identified by it and also as a guide to develop enhanced methods and processes. LCA is a burgeoning topic and it is studied by many researchers[8–10]. From raw material acquisition through production, use and disposal LCA gathers the environmental aspects and potential impacts throughout a product's life (i.e. Cradle-to-grave). In order to understand the global progress of reducing negative impacts on the environment life cycle analyses are critical. ISO 14040-14043 industry standard grades the textile products assessing the environmental impact in which the LCA is the most comprehensive approach. Social or economic impacts of sustainability is not included in the LCA. Four phases of life cycle assessment framework have been described and it is shown in Figure 1. Based on the definition of its goal and scope, inventory analysis, impact assessment and interpretation of results provides this assessment.
Goal and Scope
The goal and scope are the first phase of LCA, which sets the context of the study, therein, the following items shall be considered and clearly described;
- The functions of the product system, or, in the case of comparative studies, product systems;
- The functional unit;
- The product system to be studied;
- The system boundaries;
- Allocation procedures;
- Types of impact and methodology of impact assessment, and subsequent interpretation to be used;
- Data requirements;
- Initial data quality requirements;
- Type of critical review, if any;
- Type and format of the report required for the study.
The scope of the study may require modification according to the product design and other parameters, since LCA is an iterative technique further information is collected in this study.
Life Cycle Inventory Analysis (LCI)
The LCI is second phase used in data collection portion. It involves the “system” of interest which is straight forward based on the ISO 14040:2006 and consists of the detailed tracking of all the process flows for the entire system (i.e., from raw materials to final products, energy utilization, water, carbon and other substance emission). Henceforth, dozens of individual unit processes in the supply chain is involved as it is a complex analysis (e.g., extraction of cotton or other fibers, yarn formation, coloration, fabric formation, garmenting, finishing, transportation, retailing and distribution) as well as hundreds of tracked substances.
Life Cycle Impact Assessment (LCIA)
The inventory analysis is done by the impact assessment. Generally, the results of the inputs and outputs are focused by this phase and categorizes them strategically in order to help the environment. Globally there are various methods available to characterize and categorise the life cycle impact of the flows to and from the environment, but it can somewhat complicate the comparability of different LCA studies. Other variables in LCIA are there, apart from this which includes the system boundary, the functional unit and specific LCIA methods such as allocation. The mandatory elements for the LCIA are:
- The selection of impact categories, category indicators, and characterization models;
- The classification stage, where the inventory parameters are sorted and assigned; and
- Impact measurement, indicating where the inventory in categories is characterized, using many possible LCA methodologies.
Life Cycle Interpretation
LCA's last phase is the life cycle interpretation in which “identify, quantify, check and evaluate”, previous phases such as life cycle inventory (LCI) and or the life cycle impact assessment (LCIA) are the results from the information above. Ensuring the validity of the entire study are aided in this study.
- Identification of significant issues based on the results of the LCI and LCIA phases of an LCA;
- Evaluation of the study considering completeness, sensitivity and consistency checks;
- Conclusions, limitations and recommendations.
Product Life cycle
To reduce its resource utilization and emissions to the environment as well as improve its performance throughout its life cycle is the main purpose of this assessment. Figure 2 is an illustration of all phases in a products life cycle .
Raw material procurement
Cotton is mainly used in manufacturing denim. Occasionally, in order to produce the denims with further properties like comfortable fit and durability, the synthetic material is used. One of the most popular natural fibers used in the world is cotton as known. For cotton production 3% of world's cultivated land is used. Natural fibers are good (environmental friendly) and synthetic fibers are bad (harmful), based on previous studies on environmental facts. In the production process each fiber is different with its own sustainability challenges which cannot be ignored. Generally, natural fiber cotton is grown and not manufactured, consumes huge quantities of water and requires pesticides though it is an eco-friendly. Cotton is the most toxic crop in the world according to the data sheet published by the USDA and the organic consumers foundation. More than 25% of all the insecticides in the world and 12% of all the pesticides are used by the cotton in which insecticides are considered to be the most toxic chemicals in the world mostly. Birth defects, reproductive disorders and weaker immune systems are also included as health risks of pesticide. In order to produce one kilogram of raw cotton It would require 7-29 tons of water. Denim brands are obligating to organic cotton materials due to the above environmental and health issues. Mostly polyester and polyurethane are used in denim manufacturing as synthetic materials. There are other effects on the environment even though it requires less water and land for the manufacturing of these fibers. Nonrenewable resources (e.g. fossil fuels) are consumed in order to obtain synthetic polymers and higher GHG is emitted in the production of these fibers which requires an enormous amount of energy. Several health and toxicological threats with negative impacts of the production of synthetic fibers are caused due to the Environmental problems in waste management such as non-biodegradability.
The process where fibers are converted into yarn, then into fabric, and lastly converted into garments (3-dimensional structures) is known as manufacturing. Manufacturing of denim with respect to the inputs and outputs of the production chain for the product life cycles has been explained in a map of each process in Figure 3.
Ring spinning or open-end spinning are the two methods carried out for the Yarn formation for denim fabrics. The field of denim fabric production was dominated by the open-ended yarns for last three decades. Different places and/or countries are chosen generally in the production of the cotton and other fibers also the transportation of fiber from the place of harvest to the spinning factory in the first phase of yarn formation. A high level of energy usage is required to carry out several processes (i.e. opening, carding, combing, drawing, roving, spinning and winding) to form a yarn. The main issues related to the environmental protection during spinning are the dust, fiber and yarn waste production. There is a possibility for utilization of lubricants, chemicals, water, packaging materials and other disposables during the various processes namely blowing, carding, drawing, combing, roving, ring spinning, open-end spinning and other types of spinning processes according to the condition of the fiber. Inhalation of the dust that may cause a dangerous disease called by byssinosis (commonly called 'Brown Lung') is the highest environmental and health risk.
Weaving twill structures produces the denim fabrics. Once the warping process is completed the warp sheets must undergo the sizing process necessarily in which it contains natural or synthetic sizing agents such as polyvinyl alcohol or carboxymethyl cellulose. High levels of energy consumption are required in the process of fabric manufacturing and produces wastes from various chemicals, water, and packaging materials. The disposal of this waste, as well as excessive noise, can be issues.
Coloration of denim
During the production of the dyes, water and chemicals are used and also in dye fixation and the drying of denim as well as non-denim fabrics which is the major environmental impact in the coloration process. Before this process these materials require a pre-treatment process where it is cleaned with sodium hydroxide and detergents in order to remove natural hydrophobic substances. Water pollution is also caused by this washing process. In denim fabrics, only the warp yarns are dyed generally with indigo and sulfur dye. Excess dye is removed, dried and then sized after dyeing by rinsing it in water (water discharge in the form of colored waste water). The indigo dye has to be chemically reduced using sodium hydro sulfite as a reduction agent in the dyeing bath. Fiber absorbs the reduced indigo (with a yellow color). When exposed to air the dye which is reduced will oxidize back to the characteristic blue color[17–20].
“Garment manufacturing” is the final stage of denim supply chain also known as the Cut-Make-Trim (CMT) stage. Numerous operations like spreading, cutting, sewing, heat pressing, ironing and packaging are involved in this process. In order to complete the garment, the CMT process involves mostly manual human labor rather than yarn and fabric manufacturing. High level of energy usage; fabric waste during the cutting process (often already recycled), accessories waste, rejected garments, lubricants, water and chemical usage, use of packaging & hanging materials and the production of high carbon emissions during transport operations are the essential environmental impact assessment. Earlier generally different places and countries are chosen for the production stages from raw materials to finished textile goods as its logistical activities is an important component along the denim supply chain. Apart from manufacturing, transportation also plays an important role to transport denim to wholesalers, retailers, distribution centers and shops, using different kind of transportation (i.e. by road, maritime or air) which all have different amounts of energy consumption values and CO2 emission levels. Around 8% is estimated to be the CO2 emissions from freight transport. Eventually transport costs increases due to the price of oil and gas where the transportation to the consumer is a huge factor which consumes large quantities of oil or gas according to the LCA. “Green logistics” is to reduce the amount and distance of the transport of goods to ensure the management of a green supply chain.
Consumer use and disposal
Even now people will be passionate about the need to protect the environment and about what should be done with what they consider to be a generic material, called wastes. Life cycle of consumer use where assessment process is geared at the consumer and the manufacturer's control is no longer with them (e.g. passing on valued garments to family, friends or charity; sending for re-selling or recycling) and varies between and within regions and cultures. Consumers buy only when they need and take care of clothes to prolong their life which is encouraged by this phase and later disposed of to a landfill after one year. Effort on the care of denims are considered by most of the companies for example Levi Strauss & Co. “Care tag, for our Planet”, reminding the consumers to wash in cold and wash less. This custom varies between and within regions and cultures. Hence, it's not possible to have an omelet without disposing the egg shells. In order to reduce the amount of waste going to landfills, helps to positively affect our environment is the primary motto of the disposal stage. Waste management most commonly known strategies are the 3 R's, also known as reduce, reuse, and recycle. The product for the same purpose or for something completely different using is the meaning of reuse. Donating unwanted items to charity groups or even to a family member or friend is also included in it. The development of new materials (i.e. production or cultivation of new fibers like cotton, polyester etc.) are the main benefits of reduce and reusing. As it deduces the Greenhouse gas emission and global climatic change, and most prominently it helps to withstand the environment for future generations and in addition it saves energy and money. The collection and processing of materials that are considered trash and turning them into new products are said to be recycling [3,4,21–23]. Comparatively it saves resources and uses less energy than the production of new items. To produce one pair of jeans Levi & Strauss started the 8 bottles one jeans concept, recycling 8 PET bottles (typically beverages bottles) . For technical applications a few companies were removing the fiber from the old denim (considered as trash) such as insulation for homes and civic buildings.
Life Cycle Assessment of denims
Levi Strauss & Co conducted the LCA analysis to assess the environmental impact of a pair of Levi's Jeans made from cotton. For this study the number of items to be analyzed are the functional units. The production of one pair (women) of Levi's 501 medium stonewash jeans with a weight of 340 grams as the functional unit for this study. This study has opened new era through the analysis from cradle to grave (Seed sowing to landfill). The following categories are the environmental impact,
- Cotton production;
- Fabric production;
- Garment manufacturing;
- Transportation and distribution;
- Consumer use;
- Recycling, which then goes back to step-2; or
- Waste stream in a landfill.
For the above cycle several data were included. For example, fiber loss during the processing, in the spinning phase, the type of fiber, origin of the fiber was considered into account. The type of dyes (Indigo, sulfur, pigment etc.), weave structure, and sizing efficiency were considered in the case of coloration and weaving. The cutting efficiency (i.e. marker efficiency) materials, sundry material/weight, and packaging material/weight were included during the cut and sew phase. During the finishing phase the types of chemicals used is to be considered. Lastly, the transport mode and distance were considered and collected from all the phases of the entire supply chain.
In 21st century climatic change is one of the major concerns. Textile industry being one among the polluting industry in world, has acquired intense attention in terms of climate change, resulting in global warming, rising sea levels and extreme weather. The biggest impact on the environment is caused by the increase in consumption of textiles for clothing. Throughout the supply chain from production to finished product, it excretes a huge amount of carbon, initiating changes in the climate. Every year these changes affects the ecosystem and also human health enormously. The global warming potential of radioactive forcing and measuring the effect of emissions of CO2 and other greenhouse gases into the environment are focused by this study. The various effects of human health and the ecosystem can be expressed by the final result.
- 1 Kilogram of cotton (equivalent to a pair of jeans) production can take more than 20,000 liters of water;
- 1.5% of the world's annual energy is consumed by industrial fertilizer production. Being a key consumer of fertilizer, cotton plays a huge role in global climate change.
Textile production is held responsible for almost 20 percent of all fresh water pollution by the world bank particularly during wet processing. Globally the textile industry including denim excretes the pollutants continuously and are aware of doing unimaginable harm to the environment. The highest amount of harmful pesticides and fertilizers which pollute and spoil water and land are said to be consumed by the cotton crops as per a previous survey. A very important factor, affecting human health and the ecosystem is water consumption. At the midpoint level simply, the life cycle for LCA is expressed since there is no model providing the endpoint level. From raw material procurement to end product, the water consumption can be calculated as per the ReCiPe 2008 LCA tool. Therefore, rather than the recycled water, this study focuses mostly on water lost and damaged. There are some facts which highly correlate cotton cultivation and water consumption;
- The Aral Sea, which was the world's fourth largest lake, has been reduced to 15% of its original size as a result of irrigation for the cotton industry.
- 73% of the global cotton harvest comes from irrigated land.
An environmental problem that affects water bodies are said to be eutrophication. The process through which higher nutrient levels stimulate the growth of aquatic plants, especially algae, on the surface of still or slow-moving water bodies occurs due to eutrophication. Therefore, the sun penetration will be reduced due to the growth of algae thus reducing the oxygen level. In addition, oxygen levels are reduced by algae due to photosynthesis so both processes affect the water bodies. Microbial activity increases the resulting level of de-oxygenation upon dead algae on the floor of a lake or estuary. Eventually, due to limited available level of sunlight and oxygen it will reduce the diversity of plant and fish life that the affected waters can sustain. At the endpoint level for damage to the ecosystem are expressed by the eutrophication in LCA. Normally, Phosphorus is an important nutrient for plants, however, causing excessive algae growth in bodies of fresh water due to elevated amounts of phosphorus cause plants to soak up more nitrogen before all the phosphorus is depleted .
The damage causes by the land occupation has been assessed through this study. Generally, it refers the area of land consumed for raw materials, cultivation and production process; and the transformation of a certain area of land. Compared to other apparel products denim production requires larger area of land due cotton cultivation. Henceforth in this study the results are conveyed at the midpoint and endpoint levels due to its affects in both systems.
The loss of non-living natural resources like naturally occurring minerals, fossil fuel energy, and metals is the abiotic depletion. Essential resources like fossil fuels and minerals occupies our everyday lives and the majority of them are currently being extracted at an unsustainable rate, which seems to lead to a shortage of resources for future generations. During the cultivation and production, the results for denim the overall costs of resources lost are calculated. The midpoint and endpoint level are expressed by this study .
Interpretation and results
Climate change: The highest impact on the climate change is seen due to the number of processes which utilize resources are shown by the fabric production and consumer care in producing one pair of jeans. The conclusion of Levi's studies shows that 33.4 kilograms of CO2 emission, which is equal to a US car driven to the distance of 111 kilometers; or 246 hours watching TV on a plasma big-screen.
Large amount of water is required for fiber production and consumer care will be reflected by this result of water utilized and not reused. This should be noticed in order to find the solution. Results of Levi's studies shows that, 3781 liters, or, 3 days of household's total water needs in the USA.
Highest impact is shown by the fiber cultivation in producing one pair of denim jeans as to eutrophication. It is mainly caused due to the utilization of fertilizer and pesticides damaging the water bodies causing nutrient rich runoff water. The oxygen content in the water is affected by it generally which in turn affects the aquatic systems, Levi's studies confirms that 48.9 g PO4 emission, this is around the total amount of phosphorous found in the 1700 tomatoes.
Fiber cultivation which requires a large area is largely occupied for the production of denim jeans. Practice of cutting trees for producing energy in the forest apart from cultivation is still carried out in many developing countries. The Levi's studies shows, 12 m2/year of land, equal to seven people standing in a relaxed manner.
Textile production causing abiotic depletion is considered to be one of the largest environmental issues due to the utilization of natural resources to convert fiber to garments. Sundries consumed the highest resources with the greatest impact on abiotic depletion during the denim production. Materials, production and other findings:
- Fabric assembly, which includes yarn spinning, dyeing, weaving, and fabric finishing had notable contributions related to climate change impact and non-renewable energy consumption.
- Life cycle stages that had minimal contribution to impact, include: fabric transport, product transport, packaging, production wastes, distribution, retail, and end of life waste.
Labeling will provide the information about the environment impact of denim production to the consumers which is another potential output of a technique such as LCA. In order to identify the better environment policies used in the products eco labeling can be used. It is being optimized as the knowledge regarding the relevant aspect of denim production is not known much to the consumers. Hence customers need not necessarily be flooded with figures and scientific details. Customers need a clear image of the information about the product which allows them to choose. Practically in eco labeling there is no such custom followed which is so confusing leading to misunderstanding. Based on established methods like LCA and linked to Best available technology (BAT) criteria and sustainability standards such as ISO 260000 are to be used in eco labeling. During the forthcoming years, the life cycle assessment for other denim garments can be made by the same methodology which made from lyocell and other sustainable fibers. To compare the environmental impacts of similar products with respect to the different fibers may be possible by the ideas provided by it. In order to account the changes in fiber production, a company's sustainable initiative, availability of supplier's life cycle assessment research, available with statistical data is needed yearly and further the factors that contribute to harm of human health, the ecosystem, diversity and resource availability.
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Aravin Prince Periyasamy
Department of Material Engineering, Faculty of Textile Engineering, Technical University of Liberec, Studentska 2, Liberec 461 17, Czech Republic