This chapter first outlines the assessment framework employed for the LCA. Afterwards, the inventory data used for the assessment are described for each life cycle stage.
Goal and scope
The goal of this study is to examine the environmental hotspotsFootnote 1 of a condom's life cycle and to identify data gaps. Hence, an environmental LCA for a male condom has been conducted. Table 1 highlights the functional unit and reference flow used for the assessment. The condom studied is from the company einhorn products GmbH (einhorn). Its life is shown in Fig. 1 highlighting the foreground phases of natural rubber plantation, latex processing, condom production, einhorn’s office (i.e., corporative activities, such as research and development), and end-of-life. Included background processes are given in dashed boxes. The timeframe assessed is one year from June 2015 (start of the online shop of einhorn) to May 2016.
Impact assessment and methods
The following midpoint impact categories are assessed: climate change, terrestrial acidification, terrestrial ecotoxicity, water depletion, freshwater eutrophication, human toxicity, and photochemical oxidant formation (ReCipe (hierarchist) (v.1.1, 2014) (Goedkoop et al. 2013)). The choice of impact categories is based on Jawjit et al. (2015, p. 86) who assessed environmental impacts of natural rubber processing and used most of the impact categories employed here. Added are ecotoxicity and water depletion.
A single score value has been used to screen for sensitivity of assumptions made. This is not the classical way doing a sensitivity analysis, but it made the screening for potential points of importance faster because many of the inventory data were set up newly. The single score is derived from the endpoint categories “damage to human health,” “damage to ecosystems,” and “damage to resources” (incl. normalization and weighting (40% human health, 40% ecosystems, 20% resources)); hence, it should be noted that more than the five midpoint indicators listed above are combined to calculate this single score (Goedkoop et al. 2013). Results of the sensitivity analysis are summarized in Section 3.3.
The identification of hotspot life cycle stages (compare Section 3.4) is based on equal weighting of all impact categories. This approach was favored instead of the single-score methodology (as used for sensitivity analysis), because it was easier to understand for decision makers in the company einhorn although it means that two different weighting methodologies have been used in the study (see Section 3.3). In a first step, an average has been calculated from the contribution of a life cycle stage to all impact categories applied. In a second step, a color scheme has been applied to categorize life cycle stages to highest (contribution over 40%), high (contribution 10–20%), medium (contribution 5–10%), and minor (contribution less than 5%) impacts. This approach follows one of the suggestions given by the Life Cycle Initiative (UNEP 2017).
Open LCA (v.1.5) has been employed using Ecoinvent (v.3.2. APOS) for background processes. Decision on type of data used is related to whether the process unit is within foreground or background. For foreground phases, the most specifically available data form has been used (mainly gate-to-gate company data), while for background units, mainly generic data were employed. Data for all foreground phases are partly gathered by questionnaire (condom production and corporative activities) and consultation. Further, foreground data are collected via desktop research. With regard to consistency allocation procedures are in line with Ecoinvent data quality guidelines (Weidema et al. 2013).
Inventory
This chapter provides an overview of inventory data used. The Electronic Supplementary Material provides an overview of activities included, data limitations, assumptions, and allocations made. The allocated datasets are freely available on einhorn’s website (www.einhorn.my/science) and will be updated regularly.
Natural rubber plantation
The raw material for the product system studied is field latex,Footnote 2 harvested from the rubber tree (Hevea brasiliensis). Latex is a white, milky suspension (also called “latex milk”) consisting of rubber and non-rubber particles in water (Sethuraj and Mathew 1992; Petsri et al. 2013). It contains a dry rubber content (DRC) of about 35% (± 15%), 4–5% of non-rubber particles, and about 60% water (Sethuraj and Mathew 1992; MRB 2009). Natural rubber itself consists mainly out of polyisoprene (C5H8) with a carbon content of 88% per kilogram of dry rubber (Petsri et al. 2013). Latex is literally tapped from the rubber tree by cutting the bark, which is why the harvesting process is referred to as “tapping.” The main activities in a natural rubber plantation are preparing the land, establishing and maintaining the plantation, and harvesting.
The data for the natural rubber plantation are derived from field survey, consultation, and literature research. The latter has been used mostly to reflect the plantation cycle of 25 years (Petsri et al. 2013), while the other methods were used to assess the status quo of the plantation under consideration. For example, the average yield for plantations in Kedah (i.e., in 1025 kg/(ha x year) (MRB 2009)) has been used here to reflect local conditions over the whole plantation cycle, while the current yield of the plantation represents around 60% of the average value.
The compiled activity dataFootnote 3 (see Table 2) are based on an annual mean over the plantation cycle of 25 years. Afterwards, the land is prepared for a new plantation or other uses. Harvesting activities are included for 19 years only because harvesting starts when the trees become adult. Maintenance activities are accounted for the whole plantation cycle.
Table 2 Natural rubber plantation, activity data (annual average over 25 years plantation cycle), not allocated The considered plantation is located in the region of Kedah (Malaysia) and has an area of 80 ha with about 450 trees per hectare. The plantation started its current plantation cycle in 1994. Half of the present rubber trees were planted in 1996. Prior to 1994, the area has been used as rubber plantation at least once (information from field survey)Footnote 4. Based on this, the land preparation for the given plantation was mainly felling the natural rubber trees prior plantation. Felling by sawing machine is commonly used in Malaysia (MRB 2009). After felling the trees, roots are pulled out of the ground, and the remaining biomass is incinerated (Petsri et al. 2013). Greenhouse gas emissions (CO2, CH4, N2O) from biomass incineration have been included based on emission factors from IPCC 2006 methodology provided by Petsri et al. (2013). Not included here is land preparation, such as terracing, road construction, and the like, because it can be assumed that infrastructure already existed from previous usage (for further information, see MRB (2009)).
The included activities for plantation maintenance cover consumption of fertilizer, fungicides, pesticides, and herbicides and their water consumption. Direct emissions from agrochemical application are calculated in compliance with Ecoinvent database (Nemecek and Schnetzer 2011; Nemecek et al. 2016). However, heavy metal emissions from agrochemicals have not been included due to missing data on soil erosion and heavy metal uptake of rubber trees. Furthermore, not included are packaging of agrochemicals and their application and water consumption for cleaning the site. Additional irrigation is not applied at the given plantation. All assumptions and limitations are listed in the Electronic Supplementary Material. These points can be marked as future research question.
Harvesting is done manually; hence, it is a very labor-intensive process. The bark is cut in a certain manner until latex is oozing out and drips for 2 to 3 h. It will be collected in cups and transported to a collection point. Due to lack of data, only the application of preservatives and stimulation is included. Ammonia is a common preservative in Malaysia (alternatives are, e.g., sodium sulfite or formalin) to stop the coagulation process, depending on the time between tapping and further processing (Webster and Baulkwill 1989; Sethuraj and Mathew 1992; MRB 2009). Next to that, the rubber trees can be stimulated in order to increase their yield. The active ingredient of a common Malaysian stimulant is ethylene gas that is applied to the tree’s bark and evaporates to the air (MRB 2009). However, no further information about that process has been found, which is why ethylene gas emissions are not included. The same accounts for possible ammonia volatilization during the collection process. Tools, such as the tapping knife and headlight, organic litter, consumed river water for cleaning, as well as the transport of harvested latex and by-products to the collection point and the plantation building itself have not been included due to lack of data. They should be included in the next iteration of the dataset.
By-products of field latex are field coagula, rubber wood, and seeds. Field coagulum is latex that already coagulated in the field (e.g., cup lumps or tree laces) and can be used to produce block rubber. Rubber seeds can be used for propagation or oil production while rubber wood is sold to furniture industry, for example (MRB 2009).
Economic allocation has been applied to represent the contributions of fresh latex only (using prices as given within Table 2, cp. column for original data). Mass allocation has been rejected as the co-product rubber wood holds close to 80% of produced wet mass (cp. Table 3). For carbon sequestration, allocation is based on carbon content of the products. This means that only the carbon content of latex itself has been considered. From a life cycle perspective, it becomes clear that biogenic carbon bound in products and by-products (latex, wood, and seeds) of the plantation is released as emissions from incineration processes employed at end-of-life treatment for instance. Therefore, only the biogenic carbon bound in latex has been included as only its life cycle is assessed (i.e., 88% of dry matter). Both allocation procedures are in compliance with Ecoinvent database (Jungbluth et al. 2007; Weidema et al. 2013).
Table 3 Physical and economic allocation factors at rubber plantation Latex processing
The dry rubber content of the fresh latex needs to be concentrated to 60% to be used for condom production (MRB 2009). Basic activities are precipitation of magnesium content, centrifuging the latex, and additional chemical preservation. Skim block rubber is produced as a by-product. The fresh latex is processed by a company located in Kedah, Malaysia. Because of missing site-specific data, the activities considered within the study at hand are based on literature. The accuracy of these data (see Table 4) in comparison to on-site data is important for future research. The implementation of the literature data, its limitations, and adjustments are explained in the subsequent texts.
Table 4 Latex processing, activity data, not allocated Two different studies analyzing 4 and 10 processing sites in Thailand (Chaiprapat et al. 2015; Jawjit et al. 2015) were found to be most comprehensive and best meet the system boundary considered here (i.e., using centrifugation and skim rubber block production as by-product). However, both studies do not give information on dry rubber content which will influence the output in terms of concentrated latex. In addition, the studies do relate to high ammonia content while for the condom low ammonium content is needed for the processed latex. Hence, the amount of fresh latex needed to produce concentrated latex has been calculated based on Webster and Baulkwill (1989). This resulted in 2.17 kg fresh latex (35% DRC) needed to produce 1 kg of concentrated latex (60% DRC) and 0.056 kg of skim block rubber.
Energy and water consumption are derived from the above-mentioned studies. Their average amounts have been related to the input of fresh latex calculated previously. Furthermore, the average amount of DAP (diammonium (hydrogen) phosphate; regulating magnesium content prior to concentration) from both studies has been added. The wastewater equals the sum of water input and the difference of water in fresh and concentrated latex and rubber and solids lost during the process (rainwater and evaporation are excluded).
Concentrated latex needed for condom production is the low ammonium one (LA-type), containing less than 0.3% of preserving ammonia (ISO 2010). The so-called LA-TZ preservative system is used here. It has been the most popular in the past (Webster and Baulkwill 1989; Sethuraj and Mathew 1992), although it contains TMTD which is known to form nitrosamines that can remain in the final products and is classified as endocrine disruptor according to the SIN list.
Limitations of the data given here are missing NH3 volatilization emissions from deammonification, missing data for wastewater treatment (except electricity), emitted hydrogen sulfide and methane specific to latex-processing sites, and missing information about black and pond rubber production. As the fate of added chemicals is not completely clear, an unspecified mass of 0.01 kg per kilogram of concentrated latex is added to the output side in order to keep the mass balance. This can be marked as further research question.
The used data are allocated according to economic value, because there is no major difference between economic and physical allocation and it is consistent with allocation methodology used in Ecoinvent (Weidema et al. 2013) and other processes within the studied system. Table 5 lists the allocation factors highlighting that the difference between both is marginal.
Table 5 Physical and economic allocation factors at latex concentration Condom production
After concentration, the latex is ready to be used for the production of condoms. The processes involved are preparing the latex compound (with chemicals), dipping, vulcanization, stripping and cleaning, testing, and packaging. The condom production of the condoms takes place at Richter Rubber Technology (RRT) in Malaysia. RRT is producing condoms as well as machines to manufacture and test condoms (solely, the first is assessed here). The annual production volume in 2015 has been 554 million condoms which is more than twice as much as the annual amount of condoms sold in Germany (BZgA 2015, p. 22). Only a small share is produced for einhorn, but most condoms at RRT are produced with similar ingredients and technology as provided here.
Only very limited literature data have been available supposedly because the mixture of chemicals added to the concentrated latex is often a business secret. Hence, the data have been derived from a questionnaire to RRT and consultation. Gate-to-gate information on used ingredients, energy and water consumption, and amount of waste and wastewater have been gathered and compiled in Table 6. For business confidentiality reasons, the ingredients had to be aggregated. We hope to provide a more detailed and transparent analysis of the ingredients in future studies. Capital goods, such as machinery and production building, are not included in the dataset.
Table 6 Condom production, activity data Corporate activities
After the transportation of condoms from Malaysia to Germany, the condoms are stored at einhorn's office in Berlin (Germany) before being retailed. The activities here are dedicated to product development, sales, logistics, communication, and “fairstainability.”Footnote 5 Although it is not consistent with other phases of the life cycle, the scope of assessed activities of this phase has been broadened towards office activities (energy and water consumption) and transports, such as commuting and business travels. Prior phases only include production activities while the mentioned points have been neglected. However, for einhorn, they do represent major issues in order to decrease their environmental impact, which is why they are included here. Note that all activities are directly associated with the condom, because no other product existed during the assessed timeframe. The information has been gathered by consultation and a questionnaire.
Around 1.5 Mio condoms have been sold in one year (since the start of online retailing in June 2015). For simplification, it is assumed that there is no additional stock at the office. The office is a co-working space, i.e., four to five different companies share the office area of 238 m2. einhorn holds a share of 27% of it (equals 64.26 m2). This has been used to allocate the different office activities as no information on economic activities of all companies was available. Furthermore, information on municipal waste streams was not available too (Table 7).
Table 7 Corporative activities, allocated Logistics
The raw material extraction is done at a natural rubber plantation in the region of Kedah (Malaysia). The tapped field latex is transported to the latex-processing site (to concentrate the rubber content) and then send to condom manufacturing where the condoms are produced, tested, and packed. Afterwards, the condoms are mainly transported to Germany by ship while a minor share has been transported by plane during the assessed time period. Further road transport is done by trucks. The condoms are stored at einhorn's office in Germany and are sold via web shops and grocery stores. After usage, the condoms and packaging materials enter the end-of-life treatment. Table 8 summarizes the phases, companies involved, the transport distance from the previous phase, and details for goods transported. Note that for interpretation the logistic stages of intercontinental transport (i.e., transport from Malaysia to Germany) and retailing are outlined as separated life cycle stages because of their importance. However, they are summarized here for a better overview.
Table 8 Foreground phases, companies, and transportation distances Used retailing options are online retailing and traditional retailers, such as supermarkets and grocery stores. LCA results of retailing systems are prone to high uncertainties based on the chosen assumptions that need to be made for different retailing channels (cp. van Loon et al. 2014). Hence, we rather tried to set up a first indication of how important the retailing phase is in the condom’s life and then tried to understand it completely. The model presented here is very limited and needs to be detailed further in future work. Van Loon et al. (2014) indicate which aspects could be integrated further.
Figure 2 illustrates the retail model used, distances, additional packaging, and shares each retail channel holds. For traditional retailing, only the distance to the average consumer's location is used (380.7 km. based on a customer survey from einhorn). In addition, the traditional retailing requires the customer to buy the condom in a store, which is why a shopping trip is considered. According to the Federal Ministry for Transport and Digital Infrastructure (BMVI), a daily distance of 8.13 km per person is covered in Germany for shopping purposes with 83.1% of it done by motorized transport (car or motorcycle) (BMVI 2015). Half the way is used here to transport the condom back home. Conservatively, it is considered that all customers take the car for the shopping trip. For other online retailers, the average distance has been calculated based on consultation with einhorn (488.9 km), and the transport to the customer (380.7 km) is considered in addition. For purchasing via einhorn's online shop, only the distance to the customer is considered. The transport processes are based on the vehicle fleet of Deutsche Post DHL (DHL 2015). After consumption, a transport distance of municipal waste collection of 5 km is considered, based on the dataset for Switzerland in Ecoinvent (Doka 2007).
Connected to different retailing options are additional tertiary packaging that are added to the condom if condoms are send directly to the customer (i.e., for all online purchases). The newly added packaging is mainly used by einhorn and contains up to seven bags of condoms. It is a folding boxboard with the mass of 133.04 g (i.e., 2.7 g per condom). For simplification, it is assumed that other online retailers are using the same packaging. As the new packaging is added, the former one is discarded for online retailing. For transport to traditional retailing, the former tertiary packaging is reused, but finally also discarded in groceries and supermarkets.
End-of-life
After usage, the condoms and the packaging materials enter the end-of-life phase. As only German consumption is analyzed, this accounts for end-of-life actions too. Used condoms and discarded packaging material are the relevant waste streams under consideration.
Important choices regarding end-of-life options are made by the consumer. An online customer survey provided insights of where and how condoms are discarded. Over 87% of einhorn’s customer state that they discard used condoms into residual waste bins, followed by flushing down the toilet, using the yellow or organic. In addition, the surveys showed that close to 50% of consumers use toilet paper to discard the condom while the other half only knots the condom and discards it (einhorn 2016). The assessment in the study at hand is based on a simplified disposal route of condoms: Only the residual waste stream is assessed because it holds the highest share among the options. In addition, waste management companies, such as Berliner Stadtreinigung (BSR), advise to discard condoms into residual waste bins leading to incineration of the condom (BSR 2016). To reflect the discarding behavior, the impact of additionally used toilet tissue paper has been allocated to half of the condoms, as well. It has been assumed that three papers of three-ply toilet paper with a basic weight of 20 g/m2 and an area of 12 × 12 cm are used (Tillmann 2012). The toilet paper enters the residual waste stream and is incinerated with the used condom.
Analyzing the relevant German waste streams for the used packaging material shows that the majority of aluminum, plastic, and paper packaging not collected separately end up in energy-recovery plants (waste incineration or substitute fuels) (UBA 2015). Datasets for incineration have been available in Ecoinvent for polyethylene and paper but not for aluminum where only a general municipal solid waste incineration in Germany is used instead. Tertiary packaging is made from boxboard, which is collected separately in Germany. Between 2008 and 2013, over 88% (and here mainly separately collected) waste paper and board has been recycled leading to waste paper usage in new paper production of over 70% (UBA 2015).