Life Cycle Energy,Carbon,and Water Footprints Analysis Of Rapeseed Oil Production

Rapeseed oil is one of the edible oils with the largest demand and consumption in China.In recent years,people's demand for rapeseed oil has been increasing,while China's rapeseed oil industry also has a rapid development over the years.Now,China has become the world's largest producer and consumer of edible rapeseed oil.It is imperative to evaluate the environmental impact caused by the rapeseed oil industry,due to the environmental problems in the whole process of rapeseed oil production in China(including the planting,producing and transportation)and more attention paid by Chinese government on environment.Therefore,this study uses the life cycle assessment method as the framework to evaluate the energy,carbon and water footprint of the whole process of rapeseed oil production to quantitatively analyze the environmental impact of the whole process of rapeseed oil production.By combining the raw production data of rapeseed oil production,the national agricultural planting process data and the localized database,a complete life cycle inventory of the whole process of rapeseed oil production was built.Eight midpoint categories and three endpoint categories were considered.The characteristic analysis was carried out on the midpoint and endpoint impact categories,and the key factors causing environmental impact in the whole process of rapeseed oil production were identified.Meanwhile,the spatial analysis of endpoint impact categories at the national level was carried out for the agricultural planting process.In order to ensure the reliability of the results,uncertainty analysis and sensitivity analysis were carried out on the energy,carbon and water footprints of the whole process of rapeseed oil production.Characterization results shows that the value of energy and carbon footprints of the whole process of per ton rapeseed oil production are calculated as 726.07kg oil eq and 3889.75 kg CO2 eq,respectively.For the water footprint,the values of acidification,aquatic eutrophication,carcinogens,freshwater ecotoxicity,water scarcity,and non-carcinogens are 14.24 kg SO2 eq,4.53 kg PO43-eq,6.72×10-5 Case,5.43×104 PAF.m3.d,437.62 m3 deprived,and 1.88×10-5 case.In the endpoint categories,the impacts on ecosystem quality,human health and resource are 1.74×10-4 Species.Year,4.35×10-3 Daly and 2258.05$,respectively.The results of key factors shows that the energy,carbon and water footprints of the whole process of rapeseed oil production are mainly influenced by the agricultural planting process,including the direct process of planting,the indirect process of chemical fertilizer and diesel production.Transportation also plays a role.The main pollutants are non-point source pollutants(COD,etc.)from planting process,and heavy metals and greenhouse gas from chemical fertilizers and diesel production.In the endpoint impact categories,human health is mainly contributed by carbon footprint,ecosystem quality is mainly contributed by freshwater ecotoxicity,and resource impact category is mainly contributed by fresh water consumption.The spatial distribution of energy,carbon,and water footprint end-point categories at the agricultural planting process in the main rapeseed producing provinces in China shows that the areas with higher environmental burdens per ton rapeseed planting are Inner Mongolia,Gansu,Qinghai,Hunan and Jiangxi Province.The areas with high total environmental burden of rapeseed cultivation are mainly concentrated in Sichuan,Hunan,Hubei and Jiangxi Province.In addition,this study carried out a correlation analysis between human health/ecosystem quality and fertilizer application/pesticide loss,and the results shows that there is a positive correlation between the fertilizer application amount and human health/ecosystem quality,as well as the pesticide loss and ecological system.Therefore,reducing the use of chemical fertilizers and pesticides in agricultural planting is very necessary to reduce the environmental burden.In this study,the following measures were proposed to reduce the environmental impact during the whole process of rapeseed oil production:1)strengthening agricultural training on balanced and rational fertilization,and increasing the use of organic fertilizers;2)promoting water-saving agriculture and building water-saving projects in agriculture;3)adjusting the fuel structure,using algal biodiesel instead of diesel,using electric machinery instead of fuel machinery;4)adjusting the industrial layout,increasing rapeseed oil production enterprises in northwest China,shortening the transportation distance;5)improving the level of fine planting in low producing areas;6)reducing the use of pesticides in mountainous and hilly areas in southern China.