The Mediation Role of Environmental Performance in the Effects of Green Supply Chain Management Practices on Business Performance

Natural environment practices attract attention in today’s increasing competitive environment, and they are widely approved in practice. These practices have gained importance in customer and consumer dimension and accordingly the competition has evolved in this direction. One of the enviromental issue that has become current with the addition of “green” practices to supply chains is green supply chain management (GSCM). GSCM has been studied and examined in various ways with various studies. In this context, the question of the present research was formed as “whether environmental performance (EP) has a mediation role in the effect of GSCM practices on business performance (BP)”. Accordingly, the purpose of the present research is defining the relationships between GSCM practices, EP and BP of business that operate in the automotive industry in Konya province. In accordance with this purpose, a questionnaire was implemented on the businesses operating in automotive industry selected through simple random sampling, and the hypotheses were tested. According to the results of the analyses, there are statistically significant and positive relationships between GSCM practices, EP and BP. Additionally, GSCM practices have a positive and significant effects on BP and EP, and EP has a positive and significant effect on BP. Finally, EP has a partial mediation role in the effects of GSCM practices on BP.


Introduction
Environmental activities are among the issues that are prominent at global scale recently. As a result of the increase in the human and industrial effects on the environment, environmental issues have become more prevalent (Eltayeb and Zailani, 2009: 93). For this reason, there is an increasing need for the integration of environment friendly activities to the research and practices on supply chain management (SCM) (Srivastava, 2007: 53). In this context, inclusion of environmental interest and green practices in supply chain is an issue in the academic literature (Laosirihongthong et al., 2013(Laosirihongthong et al., : 1088, and GSCM has become a matter of increasing interest in production and supply chain studies (Srivastava, 2007: 53;Luthra et al., 2014: 20).
Among the most common GSCM practices are organizations that evaluate EP of suppliers, require measure that ensure the environmental quality of the products of suppliers, and measure waste costs for business systems (Darnall et al., 2008: 33). Additionally, the reflection of environment friendly activities on supply chains has led to a transformation in all business and organization structures. In this context, the present research aims at defining the relationships between GSCM practices, EP and BP of businesses and measuring the mediation role EP in the effect of GSCM practices of business on their BP. The review of the related literature shows that GSCM has been studied by various studies, which investigated the effects on performance. However, the present research is believed to contribute to the related literature by examining the mediation role of EP in the effects of GSCM practices on BP, as this method has been adopted by only a few studies before.
Based on the information presented above, a conceptual framework is formed for the present research first. Following this, findings obtained from the questionnaire conducted to test the hypotheses formed based on the main purpose of the research.

Green Supply Chain Management
Businesses need to meet the changes in the demands of their customers immediately. As today's customers start to demand environment friendly products and services that are produced through processes that do not harm environment, businesses need to operate their activities in a way to reflect their customers' demands (Green et al., 2019: 26). Indeed, it has become a critical issue that businesses take environment into consideration in their long-term strategies. More radical changes in the managerial and consumer perspectives in addition to the changes in regulatory and organizational environments have led many businesses to change their approaches from reactive to proactive in order to deal with environmental issues (Walls et al., 2011: 72). In this context, GSCM refers to a proactive approach to the improvement of EP of processes and products in order to meet the requirements of environmental regulations (Hsu and Hu, 2008: 205).
GSCM emerged as an organizational philosophy, which is important in reaching organizational profit and market share goals by increasing ecological efficiency of businesses and their partners and decreasing environmental risks and effects (Zhu et al., 2008: 261). This philosophy is based on both environment management and SCM. Additionally, it includes the "green" element in the SCM in dealing with effects and relationships between the SCM and the natural environment the businesses operate in (Srivastava, 2007: 54). Hervani et al. (2005) defines GSCM as the combination of green purchasing, green production/material production, green distribution/marketing and reverse logistics. Zhu and Sarkis (2007) define GSCM as the eco-initiatives that cover the all phases of the life cycle of a product from the phases of product design, production and distribution to its use and disposal at the end of its useful life by the ultimate consumer (Abdallah and Al-Ghwayeen, 2020: 491).
Green supply chain (GSC) strategies are attempts to minimize the negative effects of businesses and supply chains on the environment (Mollenkopf et al., 2010: 15). Additionally, GSC is a broad strategy adopted to manage material flow during value chains at different stages, such as source, production and distribution. This was, environment can be protected by protecting the natural resources, and decreasing the global warming and carbon footprints (Ageron et al., 2012: 171).
Practices that can be called as green supply enable the improvement of the EP of the purchased product/service or the supplier. At this point, GSC involves practices, such as the recycling and packaging of waste in cooperation with shareholders, gathering information on products, processes or suppliers, and cooperative product development (Bowen et al., 2001). GSCM practices are handles differently in the related literature (Zhu et al., 2005;Eltayeb and Zailani, 2009;Zhu et al., 2010;Perotti et al., 2012;Green et al., 2012;Hsu et al., 2013;Laosirihongthong et al., 2013;Lin, 2013;Luthra et al., 2014;De Sousa Jabbour et al., 2015;Sharma and Gandhi, 2016;Abdallah and Al-Ghwayeen, 2020). The present research studies these practices as eco-design (ED), green purchasing (GP), cooperation with customers (CWC) and internal environment management (IEM) (Abdallah and Al-Ghwayeen, 2020), which can be defined as follows: Eco-design: ED is the systematic evaluation of design performance in accordance with environment, health, safety and sustainability objectives throughout the whole product and process lifecycle (Liu et al., 2017: 183), and it is considered as one of the GSC initiatives. Green design integrates environmental dimensions to the product design process by taking the whole flow of the product within the supply chain into consideration. It is of utmost significance since most of the environmental effects resulting from the production, consumption and disposal of the product are direct results of the decisions made during design process (Eltayeb and Zailani, 2009: 97). environment certified suppliers and selecting and evaluating of suppliers based on certain environmental criteria in order to meet environmental objectives (Abdallah and Al-Ghwayeen, 2020: 492).
Cooperation with customers: It refers to businesses' cooperating with customers to design cleaner production processes that produce environment friendly products through green practices (Green et al., 2012: 293). Additionally, CWC provide businesses with information about customer preferences and needs, which enables them to respond to these needs in a shorter time and to obtain competitive advantage (Vickery et al., 2003: 526).
Internal environment management: An environment management system is made of a series of internal policies, evaluation, planning and implementation acts that effect the whole organization and its relations with the natural environment (Darnall et al., 2008: 31). IEM is the practice of developing a GSCM as an organizational necessity with the commitment and support of senior and mid-level managers (Green et al., 2012: 293).

Green Supply Chain Management, Environmental Performance and Business Performance
Businesses need to monitor, evaluate and manage their performances for a sustainable competitive advantage (Taticchi et al., 2010: 4). BP, which is a complex concept that involves efficiency, productivity and adaptability (Abdallah and Al-Ghwayeen, 2020: 494), is defined as a series of managerial and critical procedures that provides the realization of one or more pre-defined objectives of a business management (Alkunsol et al., 2019: 28).
Another important element of performance is the EP. EP is defined by Younis et al. (2016) as a business's ability to minimize air emissions and all kinds of waste, decrease the consumption of toxic and hazardous materials and reduce environmental accidents (Abdallah and Al-Ghwayeen, 2020: 493). Today, businesses consider EP as a social objective rather than an issue of cost, risk or image (Dheeraj and Vishal, 2012: 77). Additionally, EP is measured in different ways in various studies (Al-Tuwaijri et al., 2004: 453).
GSCM focusses on reducing waste and increasing the efficiency of supply chain through product and service innovation, which requires the common supply chain efforts of suppliers, distributers and customers (Kim et al., 2011: 284). In addition, GSCM is a proactive approach to increasing EP (Lin, 2013: 32), which refers to the interaction and synergy between shareholders to improve EP, reduce waste and minimize cost (De Giovanni and Vinzi, 2012: 907). Indeed, with green supply chain management practices, businesses can reduce the ecological effects of industrial activities without compromising on cost, quality, performance, safety or energy use efficiency. Moreover, controlling product line to meet environmental regulations not only minimizes the ecological damage, but also provides economic profit (Srivastava, 2007: 68). Accordingly, the relationships between GSCM practices, BP and EP have been investigated in various studies.
According to the literature related to the relationship between GSCM practices and BP, there is a positive relationship between GSCM practices and BP, and GSCM practices have a positive effect on BP (Zhu and Sarkis, 2004;Zhu and Sarkis, 2007;Testa and Iroldo, 2010;Golicic and Smith, 2013;Abdallah and Al-Ghwayeen, 2020). Additionally, the related literature on the relationship between GSCM practices and EP presents positive relationships between variables (Geffen and Rothenberg, 2000;Zhu and Sarkis, 2004;Zhu and Sarkis, 2007;Abdallah and Al-Ghwayeen, 2020). Moreover, a positive relationship between EP and BP has been reported (Klassen and McLaughlin, 1996;Abdallah and Al-Ghwayeen, 2020). Based on the information provided above, the relationships between these variables form the basis of the present research, and the relationships between the variables and the hypotheses formed within this framework are investigated in the methodology of the present research.

Research Methodology
This part presents information on the method and sample of the present research. Additionally, hypotheses formed based on the research question are tested.

Research Method and Sample
Within the scope of the qualitative research method, structures questionnaire forms were implemented on automotive businesses operating within the body of Konya Chamber of Industry. Simple random sampling (SRS) method was adopted for the present research. The basic principle of the SRS is that the possibility of selection is equal for any sample within the research universe (Meng, 2013). This method is commonly adopted when the features of the units forming the universe does not matter much for the research and the features of the units are homogenous (Gürbüz and Şahin, 2018: 135). Accordingly, the present research adopted SRS method.
The questionnaire form created for the present research consists of four parts. The first part consists of demographic questions. The other parts consist of questions on GSCM practices, EP and BP respectively.
Within the scope of the present research, questions measuring GSCM practices (20 items), EP (6 items) and BP (5 items) were obtained making use of the scale developed by Abdallah and Al-Ghwayeen (2020). All items in the questionnaire were scored on 5point Likert scale. It was found that there were 300 businesses † operating in automotive industry in the province of Konya, and the analyses conducted for the present research were done with data collected from 130 of these businesses. In accordance with these data, it can be claimed that the sample can represent the universe (Coşkun et al., 2015: 137). † There are 300 businesses operating in automotive industry in Konya. This data is obtained from Konya Chamber of Industry on 22.11.2019. At the same time, the surveys were conducted in December 2019. The reliability of the scales adopted was tested before testing the hypotheses. Information of the reliability of the scales is presented in Table 1 below.  (Sekaran, 2003: 311;Gürbüz and Şahin, 2018: 333). Therefore, it can be claimed that the adopted scales are reliable.

Research Hypotheses
Quantitative methodology was adopted in the present research to answer the question "Does EP have a mediation role in the effect of GSCM practices on BP?". Hypotheses formed in accordance with this purpose are listed below. H3: EP has a positive and significant effect on BP.
H4: EP has a mediation role in the effect of GSCM practices on BP.

Testing the Research Hypotheses
Before testing the hypotheses, GSCM practices of businesses were evaluated. Findings on the GSCM are presented in Table 2. According to the data related to the GSCM practices of businesses, the mean value is above average (3.75). This value indicates that businesses conduct GSCM practices above average. In terms of the dimensions of GSCM practices, IEM dimension is also above average (3.85), and "businesses emphasize cross-functional cooperation for environmental improvements" (4.35). The mean value for CWC is also above average (3.82). The highest scored item in this dimension is "cooperates with customers to produce eco-designs" (4.28). Mean score for ED also is above average (3.67). In this dimension, the highest scored item is about "emphasizing design of products that can be reused, recycled, and recovery of component parts" (3.66). Another dimension of GSCM practices, GP is also scored above average (3.65). Within this dimension, "having partnerships with suppliers that aim to environmental solutions and/or development environmentally friendly products" item has received the highest score (3.87). With a general review of Table 2, it can be claimed that businesses emphasize the use of GSCM practices and have placed them within their business systems.
Evaluation of the EP of the businesses is presented in Table 3. The evaluation of Table 3 shows that EP of the businesses is scored above average (3.65). In terms of performance criteria, it can be seen that businesses have reduced energy consumption during the last three years compared to competitors (4.08); they have reduced air emissions during the last three years compared to competitors (3.96); they have reduced effluent wastes during the last three years compared to competitors (3.92); they have sought to improve its environmental image /position during the last three years compared to competitors (3.81); they have reduced consumption of hazardous/toxic material during the last three years compared to competitors (3.21); and they have reduced solid wastes during the last three years compared to competitors (2.95). A general evaluation of Table 3 shows that businesses have experienced problems in reducing solid wastes compared to competitors. It can be suggested that businesses need to take measures in order to solve this problem.
Findings on the general BP of businesses are presented in Table 4.

Table 4. Findings on the General Business Performance of Businesses
General BP X S.D. Our sales have increased during the last three years compared to competitors.
3.88 1.06 Our customer satisfaction level has increased during the last three years compared to competitors.
3.73 0.97 Our market share has increased during the last three years compared to competitors. 3.69 0.96 Our firm has achieved a high percentage of profits during the last three years compared to competitors.
3.47 1.21 Our general competition position has improved during the last three years compared to competitors. As presented in Table 4, general BP of businesses is above average (3.64). In terms of performance criteria, it can be seen that businesses have increased their sales during the last three years compared to competitors (3.88). Their customer satisfaction levels have also increased during the last three years compared to competitors (3.73). Similarly, market shares of businesses have increased during the last three years above average (3.69). During the last three years, there have been improvement in the profits (3.47) and their general competition positions (3.44) compared to competitors.
In order to test research hypotheses, Pearson Correlation analysis was conducted first. Correlation values obtained from the analysis are presented in Table 5. e-ISSN: 2148-2683 The correlations between GSCM practices, EP and BP show positive and significant relationships between variables (p<0.001). As for the relationships between variables separately in this context, there are mid-level relationships between GSCM practices and EP (0.669); GSCM Practices and BP (0.652); and EP and BP (0.619). Hierarchical regression analysis was conducted to test the research hypotheses and the results are presented in Table 6 below. Multiple regression analysis was conducted in order to define the mediation role of EP in the relationship between GSCM practices and BP. According to the multiple regression analysis results presented in Table 6, regression model is statistically significant (p<0.001). In the scope of mediation effect model suggested by Baron and Kenny (1986), the effects of GSCM practices on BP was studies in order to define the mediation effect. Accordingly, explanatory variable, supply chain practices explains the 42.4% of the variance in the dependent variable, BP (R 2 =0.424; F= 94.398). In the second step, the effect of GSCM practices on EP was examined, and accordingly GSCM practices can explain the 44.7% of the variance in EP (R 2 =0.447; F= 103.636). In the third step, the effect of EP on BP was studies and it was found that EP can explain the 38.3% of the variance in BP (R 2 =0.383; F= 79.377). In the last step, GSCM practices and EP variables were added in the model together, and the effect of these two variables on BP was examined, and according to the results GSCM practices and EP can explain the 48.5% of the variance in BP (R 2 =0.485; F= 59.799). When EP variable was added to the model at the end of the regression analysis, the effect of SCM practices on BP decreased from β= 0.652 to β= 0.430. Additionally, when EP variable was added to the model, there was an increase from R 2 =0.424 to R 2 =0.485, and therefore explaining power of the regression model increased. After EP was added to the model, the effects of GSCM practices decreased, yet this effect was still significant (p<0.001). This result shows that EP is a variable with partial mediation role in the effect of GSCM practices on BP. Sobel test was made to define the significance of this mediation role. According to the Sobel analysis results, z value was calculated as 6.70, which was statistically significant (p<0.001).
According to the multiple regression analysis results, the lowest of VIF values was 1.810, which was lower than the upper bound 10. It was also found that the lowest tolerance value in the model was 0.553, which was higher than the lower bound 0.10. The highest CI value in the model was calculated as 18.527, which was significantly lower than the upper bound 30. Therefore, there is no multiple correlation problem in the model. Additionally, the highest Durbin-Watson coefficient in the model was 2.317, which showed that there was no auto-correlation problem. Based on the results of the multiple regression analysis, hypotheses H1 "GSCM practices have a positive and significant effect on BP.", H2 "GSCM practices have a positive and significant effect on EP.", H3 "EP has a positive and significant effect on BP." and H4 "EP has a mediation role in the effect of GSCM practices on BP." were accepted.

Conclusion
Within the scope of the main objective of the present research, first the relationships between GSCM practices, EP and BP were examined. Four hypotheses formed on the basis of these relationships were tested. According to the obtained findings, GSCM practices have a positive and significant effect on BP and EP; and EP has a positive and significant effect on BP. Additionally, EP has a partial mediation role in the effect of GSCM practices on BP. These findings are in agreement with the findings of similar studies in the related literature (Klassen and McLaughlin, 1996;Geffen and Rothenberg, 2000;Zhu and Sarkis, 2004;Zhu and Sarkis, 2007;Testa and Iroldo, 2010;Golicic and Smith, 2013;Abdallah and Al-Ghwayeen, 2020).
According to the results of the analyses conducted for the present research, the level of realizing GSCM practices in above average for businesses (3.75). EP (3.65) and BP (3.64) levels of businesses are also above average. The most critical element in BP of businesses was that the item "businesses have reduced solid wastes during the last three years compared to competitors" within the EP criteria was below average (2.95). According to this finding, it is suggested that businesses act more consciously in terms of reducing solid wastes and adapt this to their business cultures.
The present research is limited to businesses operating in automotive industry in Konya province. Further studies can be conducted in different cities/samples or on other industries in Konya. Additionally, since the present research was conducted within certain time limitations, taken the nature of research questions and hypotheses, further studies can be conducted in longer time periods in terms of data collection.