Assessing environmental impacts associated with freshwater consumption along the life cycle of animal products: the case of Dutch milk production in Noord-Brabant

Purpose

The assessment of water footprints of a wide range of products has increased awareness on preserving freshwater as a resource. The water footprint of a product was originally defined by Hoekstra and Hung (2002) as the sum of the volumetric water use in terms of green, blue and grey water along the entire life cycle of a product and, as such, does not determine the environmental impact associated with freshwater use. Recently, several papers were published that describe building blocks that enable assessment of the site-specific environmental impact associated with freshwater use along the life cycle of a global food chain, such as the impact on human health (HH), ecosystem quality (EQ) or resource depletion (RD). We integrated this knowledge to enable an assessment of the environmental impact associated with freshwater use along the life cycle of milk production, as a case for a global food chain.

Material and methods

Our approach innovatively combined knowledge about the main impact pathways of freshwater use in life cycle assessment (LCA), knowledge about site-specific freshwater impacts and knowledge about modelling of irrigation requirements of global feed crops to assess freshwater impacts along the life cycle of milk production. We evaluated a Dutch model farm situated on loamy sand in the province of Noord-Brabant, where grass and maize land is commonly irrigated.

Results and discussion

Production of 1 kg of fat-and-protein corrected milk (FPCM) on the model farm in Noord-Brabant required 66 L of consumptive water. About 76 % of this water was used for irrigation during roughage cultivation, 15 % for production of concentrates and 8 % for drinking and cleaning services. Consumptive water use related to production of purchased diesel, gas, electricity and fertiliser was negligible (i.e. total 1 %). Production of 1 kg of FPCM resulted in an impact on HH of 0.8?×?10^?9 disability adjusted life years, on EQ of 12.9?×?10^?3 m²?×?year and on RD of 6.7 kJ. The impact of producing this kilogram of FPCM on RD, for example, was caused mainly by cultivation of concentrate ingredients, and appeared lower than the average impact on RD of production of 1 kg of broccoli in Spain.

Conclusions

Integration of existing knowledge from diverse science fields enabled an assessment of freshwater impacts along the life cycle of a global food chain, such as Dutch milk production, and appeared useful to determine its environmental hotspots. Results from this case study support earlier findings that LCA needs to go beyond simple water volume accounting when the focus is on freshwater scarcity. The approach used, however, required high-resolution inventory global data (i.e. especially regarding crop yield, soil type and root depth), and demonstrated a trade-off between scientific quality of results and applicability of the assessment method.     

Effects of irrigation on the soil CO2 efflux from different poplar clone plantations in arid northwest China

Aims

Soil respiration in forest plantations can be greatly affected by management practices such as irrigation. In northwest China, soil water is usually a limiting factor for the development of forest plantations. This study aims to examine the effects of irrigation intensity on soil respiration from three poplar clone plantations in this arid area.

Methods

The experiment included three poplar clones subjected to three irrigation intensities (without, low and high). Soil respiration was measured using a Li-6400-09 chamber during the growing season in 2007.

Results

Mean soil respiration rates were 2.92, 4.74 and 3.49 μmol m^?2 s^?1 for control, low and high irrigation treatments, respectively. Soil respiration decreased once soil water content was below a lower (14.8 %) or above an upper (26.2 %) threshold. When soil water content ranged from 14.8 % to 26.2 %, soil respiration increased and correlated with soil temperature. Fine root also played a role in the significant differences in soil CO₂ efflux among the three treatments. Furthermore, the three poplar hybrid clones responded differently to irrigation regarding fine root production and soil CO₂ efflux.

Conclusions

Irrigation intensity had a strong impact on soil respiration of the three poplar clone plantations, which was mainly because fine root biomass and microbial activities were greatly influenced by soil water conditions. Our results suggest that irrigation management is a main factor controlling soil carbon dynamics in forest plantation in arid regions.     

Life cycle assessment of cheese and whey production in the USA

Purpose

A life cycle assessment was conducted to determine a baseline for environmental impacts of cheddar and mozzarella cheese consumption. Product loss/waste, as well as consumer transport and storage, is included. The study scope was from cradle-to-grave with particular emphasis on unit operations under the control of typical cheese-processing plants.

Methods

SimaPro© 7.3 (PRé Consultants, The Netherlands, 2013) was used as the primary modeling software. The ecoinvent life cycle inventory database was used for background unit processes (Frischknecht and Rebitzer, J Cleaner Prod 13(13–14):1337–1343, 2005), modified to incorporate US electricity (EarthShift 2012). Operational data was collected from 17 cheese-manufacturing plants representing 24 % of mozzarella production and 38 % of cheddar production in the USA. Incoming raw milk, cream, or dry milk solids were allocated to coproducts by mass of milk solids. Plant-level engineering assessments of allocation fractions were adopted for major inputs such as electricity, natural gas, and chemicals. Revenue-based allocation was applied for the remaining in-plant processes.

Results and discussion

Greenhouse gas (GHG) emissions are of significant interest. For cheddar, as sold at retail (63.2 % milk solids), the carbon footprint using the IPCC 2007 factors is 8.60 kg CO₂e/kg cheese consumed with a 95 % confidence interval (CI) of 5.86–12.2 kg CO₂e/kg. For mozzarella, as sold at retail (51.4 % milk solids), the carbon footprint is 7.28 kg CO₂e/kg mozzarella consumed, with a 95 % CI of 5.13–9.89 kg CO₂e/kg. Normalization of the results based on the IMPACT 2002+ life cycle impact assessment (LCIA) framework suggests that nutrient emissions from both the farm and manufacturing facility wastewater treatment represent the most significant relative impacts across multiple environmental midpoint indicators. Raw milk is the major contributor to most impact categories; thus, efforts to reduce milk/cheese loss across the supply chain are important.

Conclusions

On-farm mitigation efforts around enteric methane, manure management, phosphorus and nitrogen runoff, and pesticides used on crops and livestock can also significantly reduce impacts. Water-related impacts such as depletion and eutrophication can be considered resource management issues—specifically of water quantity and nutrients. Thus, all opportunities for water conservation should be evaluated, and cheese manufacturers, while not having direct control over crop irrigation, the largest water consumption activity, can investigate the water use efficiency of the milk they procure. The regionalized normalization, based on annual US per capita cheese consumption, showed that eutrophication represents the largest relative impact driven by phosphorus runoff from agricultural fields and emissions associated with whey-processing wastewater. Therefore, incorporating best practices around phosphorous and nitrogen management could yield improvements.     

Life cycle assessment of fuel ethanol from sugarcane in Argentina

Purpose

The production of bioethanol in Argentina is based on the sugarcane plantation system, with extensive use of agricultural land, scarce use of fertilizers, pesticides, and artificial irrigation, and burning of sugarcane prior to harvesting. The objective of this paper is to develop a life cycle assessment (LCA) of the fuel ethanol from sugarcane in Tucumán (Argentina), assessing the environmental impact potentials to identify which of them cause the main impacts.

Methods

Our approach innovatively combined knowledge about the main impact pathways of bioethanol production with LCA which covers the typical emission-related impact categories at the midpoint life cycle impact assessment. Real data from the Argentinean industry subsystems have been used to perform the study: S1—sugarcane production, S2—milling process, S3—sugar production, and S4—ethanol production from molasses, honey, or sugarcane juice.

Results and discussion

The results are shown in the three alternative pathways to produce bioethanol. Different impact categories are assessed, with global warming potential (GWP) having the highest impact. So, the production of 1 kg of ethanol from molasses emitted 22.5 kg CO₂ (pathway 1), 19.2 kg CO₂ from honey (pathway 2), and 15.0 kg CO₂ from sugarcane juice (pathway 3). Several sensitivity analyses to study the variability of the GWP according to the different cases studied have been performed (changing the agricultural yield, including economic and calorific allocation in sugar production, and modifying the sugar price).

Conclusions

Agriculture is the subsystem which shows the highest impact in almost all the categories due to fossil fuel consumption. When an economic and calorific allocation is considered to assess the environmental impact, the value is lower than when mass allocation is used because ethanol is relatively cheaper than sugars and it has higher calorific value.     

Life cycle assessment of sugarcane ethanol production in India in comparison to Brazil

Purpose

India’s biofuel programme relies on ethanol production from sugarcane molasses. However, there is limited insight on environmental impacts across the Indian ethanol production chain. This study closes this gap by assessing the environmental impacts of ethanol production from sugarcane molasses in Uttar Pradesh, India. A comparative analysis with south-central Brazilian sugarcane ethanol is also presented to compare the performance of sugarcane molasses-based ethanol with sugarcane juice-based ethanol.

Methods

The production process is assessed by a cradle-to-gate life cycle assessment. The multifunctionality problem is solved by applying two variants of system expansion and economic allocation. Environmental impacts are assessed with Impact 2002+ and results are presented at the midpoint level for greenhouse gas emissions, non-renewable energy use, freshwater eutrophication and water use. Furthermore, results include impacts on human health and ecosystem quality at the damage level. Sensitivity analysis is also performed on key contributing parameters such as pesticides, stillage treatment and irrigation water use.

Results and discussion

It is found that, compared to Brazilian ethanol, Indian ethanol causes lower or comparable greenhouse gas emissions (0.09–0.64 kgCO_2eq/kg_ethanolIN, 0.46–0.63 kgCO_2eq/kg_ethanolBR), non-renewable energy use (?0.3–6.3 MJ/kg_ethanolIN, 1–4 MJ/kg_ethanolBR), human health impacts (3.6?·?10^?6 DALY/kg_ethanolIN, 4?·?10^?6 DALY/kg_ethanolBR) and ecosystem impairment (2.5 PDF?·?m²?·?year/kg_ethanolIN, 3.3 PDF?·?m²?·?year/kg_ethanolBR). One reason is that Indian ethanol is exclusively produced from molasses, a co-product of sugar production, resulting in allocation of the environmental burden. Additionally, Indian sugar mills and distilleries produce surplus electricity for which they receive credits for displacing grid electricity of relatively high CO₂ emission intensity. When economic allocation is applied, the greenhouse gas emissions for Indian and Brazilian ethanol are comparable. Non-renewable energy use is higher for Indian ethanol, primarily due to energy requirements for irrigation. For water use and related impacts, Indian ethanol scores worse due groundwater irrigation, despite the dampening effect of allocation. The variation on greenhouse gas emissions and non-renewable energy use of Indian mills is much larger for high and low performance than the respective systems in Brazil.

Conclusions

Important measures can be taken across the production chain to improve the environmental performance of Indian ethanol production (e.g. avoiding the use of specific pesticides, avoiding the disposal of untreated stillage, transition to water efficient crops). However, to meet the targets of the Indian ethanol blending programme, displacement effects are likely to occur in countries which export ethanol. To assess such effects, a consequential study needs to be prepared.     

Life cycle assessment of the supply and use of water in the Segura Basin

Purpose

In this paper, the combined life cycle assessment of the water supply alternatives and the water use in a water-stressed watershed in Spain (the Segura) is presented. Although it is a dry area, agriculture and tourism are very profitable sectors with high water demands. Thus, external water supply alternatives including water transfers or desalination partly balance the reduced natural water availability to cover the existing water demands.

Methods

In order to integrate both the impact of water supply alternatives and water use, the ReCiPe method was used to assess the water supply alternatives at the endpoint approach with the three specific damage categories: human health, ecosystem diversity and damage to resources availability. At the same time, the water use impact was calculated and grouped in the same categories. Firstly, one average cubic metre of water at the user's gate in the Segura Basin area was taken as the functional unit. As irrigation and drinking water constitute the principal water uses, it was considered that to separately analyse 1 m³ used for irrigation and 1 m³ destined to drinking purposes could provide interesting information. Then, these units were also considered as functional units. Then, three additional hypothetical scenarios were introduced: two of them defined by a strong variability in rainfall and the third by a sudden diminution of water transferred from a neighbouring basin.

Results and discussion

Regarding the facilities to provide 1 m³ at user's gate in the Segura Basin, results showed that the seawater desalination plants obtained the highest score for all the three considered damage categories, followed by the Tajo–Segura water transfer, the groundwater, the local surface waters and the water reuse. In relation to the water use impact, the damage to ecosystems diversity was very representative with respect to the one coming from water supply infrastructures because irrigation constituted 85 % of the total demand.

Conclusions

The diversification of water supply alternatives within a region considerably increases any environmental impact, primarily stemming from the additional required infrastructures, and frequently from the use of external water sources for their uses. Thus, users and policy makers should be aware of the costs that a guaranteed water supply entails. In water-scarce territories, the use of external solutions such as desalination or water transfer either increase the environmental impact due to their high energy consumption or they are limited by existing climate variability. Therefore, they cannot be considered as the definite solution, which would be a balance between renewable sources and existing demands.     

A regulated deficit irrigation strategy for hedgerow olive orchards with high plant density

Background & Aims

There is not a consensus on the best irrigation approach for super-high density (SHD) olive orchards. Our aim was to design and test a regulated deficit irrigation (RDI) strategy for a sustainable balance between water saving, tree vigour and oil production.

Methods

We tested our RDI strategy for 3 years in an ‘Arbequina’ orchard with 1,667 trees ha^?1. Two levels of irrigation reduction were applied, 60RDI and 30RDI, scaled to replacing 60 % and 30 %, respectively, of the of irrigation needs (IN). We also had a full irrigation (FI) treatment as control, with IN totalling 4,701 m³ ha^?1

Results

The 30RDI treatment showed the best balance between water saving, tree vigour and oil production. With a yearly irrigation amount (IA) of 1,366 m³ ha^?1, which meant 72 % water saving as compared to FI, the reduction in oil yield was 26 % only.

Conclusions

Our results, together with recent knowledge on the effect of water stress on fruit development, allowed us to suggest a potentially improved RDI strategy for which a total IA of ca. 2,100 m³ ha^?1 was calculated. Both some management details and the benefits of this suggested RDI strategy are still to be tested.     

Soil CO2 efflux in response to the addition of water and fertilizer in temperate semiarid grassland in northern China

Background and aims

Knowledge about the effects of water and fertilizer on soil CO₂ efflux (SCE) and Q ₁₀ is essential for understanding carbon (C) cycles and for evaluating future global C balance. A two-year field experiment was conducted to determine the effects of water, fertilizer, and temperature on SCE in semiarid grassland in northern China.

Methods

SCE, as well as environmental factors was measured in two grasslands, one with bunge needlegrass (BNE, Stipa bungeana) and one with purple alfalfa (ALF, Medicago sativa), with four treatments: CK (unwatered and unfertilized); W (50 mm water addition yr^?1); F (50 kg phosphorus (P) fertilizer ha^?1 yr^?1 for ALF, 100 kg nitrogen (N)?+?50 kg P fertilizer ha^?1 yr^?1 for BNE); and W + F.

Results

During the 11-month experimental period from July 2010 to October 2011, the addition of water consistently stimulated mean SCE in BNE and ALF, and the positive effects were relatively stronger during dry seasons. P fertilization consistently enhanced SCE in ALF, and the positive effect was strongly dependent on the availability of soil water. The effects of N plus P fertilization on SCE in BNE varied seasonally from significant increases to small reductions to no response. Water addition increased the Q ₁₀ of SCE in ALF by 11 % but had no effect in BNE. Fertilization, however, reduced the Q ₁₀ of SCE by 21 % and 13 % for BNE and ALF, respectively. Models that rely only on Q ₁₀ underestimated the emissions of soil CO₂ by 8–15 % at the study site, which was mediated by species and treatment.

Conclusions

Responses of SCE and its temperature sensitivity to water and fertilizer may vary with species and depend on the period of measurement. Models of SCE need to incorporate the availability of ecosystemic water and nutrients, as well as species, and incorporate different environmental factors when determining the impact of water, nutrients, and species on SCE.     

Irrigation mix: how to include water sources when assessing freshwater consumption impacts associated to crops

Purpose

Impacts of activities related to freshwater use are gaining interest among the life cycle assessment (LCA) community and several approaches are nowadays available in the literature. However, the general trend still is to ignore the assessment of its impact or, luckily, its inclusion on the inventory. This paper describes a procedure to incorporate water source information at the inventory level and evaluate the influence of that profile on the environmental impact assessment level.

Methods

The methodology lies on two main elements: the “irrigation mix” concept and the freshwater ecosystem impact indicator already defined in the literature. By doing so, the results obtained can be easily integrated in LCA studies of irrigated crops, or more complex studies with agricultural ingredients, where only information regarding the amount (but not the origin) of irrigation water is available.

Results and discussion

The results make more visible the benefits associated to the use of nonconventional, artificial water sources, by quantifying the improvement achieved on the water stress of a specific basin. Besides, the irrigation mix gives a better picture of the real contribution of irrigation to other impact categories (here, the global warming potential). Finally, the results were applied in a LCA study of lettuce production (an irrigated product cultivated in the studied region), and the method was analyzed against the criteria defined by the International Reference Life Cycle Data System handbook.

Conclusions

The inclusion of the water mix in the inventory level (irrigation profile) as well as in the impact assessment level (water stress index) is straightforward to apply by LCA practitioners, resulting in a more realistic assessment of the impacts of freshwater consumption associated to crops. The implementation on a case study allowed the quantification of promoting alternative water sources in a region suffering from significant water stress as well as to improve knowledge on the environmental impact associated to freshwater consumed by one of the irrigated crops grown there. We recommend using the approach defined here in order to check its applicability to other river basins and products.     

Soil microorganisms respond to five years of climate change manipulations and elevated atmospheric CO2 in a temperate heath ecosystem

Background and aims

Soil microbial responses to global change can affect organic matter turnover and nutrient cycling thereby altering the overall ecosystem functioning. In a large-scale experiment, we investigated the impact of 5 years of climate change and elevated atmospheric CO₂ on soil microorganisms and nutrient availability in a temperate heathland.

Methods

The future climate was simulated by increased soil temperature (+0.3 °C), extended pre-summer drought (excluding 5–8 % of the annual precipitation) and elevated CO₂ (+130 ppm) in a factorial design. Soil organic matter and nutrient pools were analysed and linked to microbial measures by quantitative PCR of bacteria and fungi, chloroform fumigation extraction, and substrate-induced respiration to assess their impact of climate change on nutrient availability.

Results

Warming resulted in higher measures of fungi and bacteria, of microbial biomass and of microbial growth potential, however, this did not reduce the availability of nitrogen or phosphorus in the soil. Elevated CO₂ did not directly affect the microbial measures or nutrient pools, whereas drought shifted the microbial community towards a higher fungal dominance.

Conclusions

Although we were not able to show strong interactive effects of the global change factors, warming and drought changed both nutrient availability and microbial community composition in the heathland soil, which could alter the ecosystem carbon and nutrient flow in the long-term.     

Life cycle environmental impacts and costs of beer production and consumption in the UK

Purpose

Global beer consumption is growing steadily and has recently reached 187.37 billion litres per year. The UK ranked 8th in the world, with 4.5 billion litres of beer produced annually. This paper considers life cycle environmental impacts and costs of beer production and consumption in the UK which are currently unknown. The analysis is carried out for two functional units: (i) production and consumption of 1 l of beer at home and (ii) annual production and consumption of beer in the UK. The system boundary is from cradle to grave.

Methods

Life cycle impacts have been estimated following the guidelines in ISO 14040/44; the methodology for life cycle costing is congruent with the LCA approach. Primary data have been obtained from a beer manufacturer; secondary data are sourced from the CCaLC, Ecoinvent and GaBi databases. GaBi 4.3 has been used for LCA modelling and the environmental impacts have been estimated according to the CML 2001 method.

Results and discussion

Depending on the type of packaging (glass bottles, aluminium and steel cans), 1 l of beer requires for example 10.3–17.5 MJ of primary energy and 41.2–41.8 l of water, emits 510–842 g of CO₂ eq. and has the life cycle costs of 12.72–14.37 pence. Extrapolating the results to the annual consumption of beer in the UK translates to a primary energy demand of over 49,600 TJ (0.56 % of UK primary energy consumption), water consumption of 1.85 bn hl (5.3 % of UK demand), emissions of 2.16 mt CO₂ eq. (0.85 % of UK emissions) and the life cycle costs of £553 million (3.2 % of UK beer market value). Production of raw materials is the main hotspot, contributing from 47 to 63 % to the impacts and 67 % to the life cycle costs. The packaging adds 19 to 46 % to the impacts and 13 % to the costs.

Conclusions

Beer in steel cans has the lowest impacts for five out of 12 impact categories considered: primary energy demand, depletion of abiotic resources, acidification, marine and freshwater toxicity. Bottled beer is the worst option for nine impact categories, including global warming and primary energy demand, but it has the lowest human toxicity potential. Beer in aluminium cans is the best option for ozone layer depletion and photochemical smog but has the highest human and marine toxicity potentials.

     

Increased prevalence of tumor-infiltrating regulatory T cells is closely related to their lower sensitivity to H2O2-induced apoptosis in gastric and esophageal cancer

Purpose and experimental design

Although an increase in regulatory T cells (Tregs) is observed in tumor microenvironments, the underlying mechanism is not fully clarified. Since it was suggested that Tregs showed a lower sensitivity toward oxidative stress in comparison with conventional T cells, in the present study, we investigated the H₂O₂ production and apoptosis of Tregs in gastric and esophageal cancer tissues, employing flow cytometric analysis using fresh samples (n = 93) and immunohistochemical analysis (n = 203).

Results

The increased tumor-infiltrating Tregs coexisted with elevated H₂O₂ production according to disease progression. The grade of apoptosis in Tregs was less pronounced than that in conventional T cells, and there was a positive correlation between H₂O₂ production and the grade of apoptosis in conventional T cells, while there was no correlation between H₂O₂ production and the grade of apoptosis in Tregs. Moreover, Tregs were less sensitive to H₂O₂-induced apoptosis compared with conventional T cells in vitro.

Conclusions

We have demonstrated that the increased prevalence of tumor-infiltrating Tregs closely related to their lower sensitivity to H₂O₂-induced apoptosis.     

Potential for optimized production and use of rapeseed biodiesel. Based on a comprehensive real-time LCA case study in Denmark with multiple pathways

Purpose

Several factors contribute to the current increased focus on alternative fuels such as biodiesel, including an increasing awareness of the environmental impact of petrochemical (PC) oil products such as PC diesel, the continuously increasing price of PC oil, and the depletion of PC oil. For these reasons, the European Union has enacted a directive requiring each member state to ensure that the share of energy from renewable sources in transport be at least 10 % of the final consumption of energy by 2020 (The European Parliament and the Council 2009). This LCA study assesses the specific environmental impacts from the production and use of biodiesel as it is today (real-time), based on rapeseed oil and different types of alcohols, and using technologies that are currently available or will be available shortly. Different options are evaluated for the environmental improvement of production methods. The modeling of the LCA is based on a specific Danish biodiesel production facility.

Methods

The functional unit is “1,000 km transportation for a standard passenger car.” All relevant process stages are included, such as rapeseed production including carbon sequestration and N₂O balances, and transportation of products used in the life cycle of biodiesel. System expansion has been used to handle allocation issues.

Results and discussion

The climate change potential from the production and use of biodiesel today is 57 kg CO₂-eq/1,000 km, while PC diesel is 214 kg CO₂-eq/1,000 km. Options for improvement include the increased use of residual straw from rapeseed fields for combustion in a power plant where carbon sequestration is considered, and a change in transesterification from a conventional process to an enzymatic process when using bioethanol instead of PC methanol. This research also evaluates results for land use, respiratory inorganics potential, human toxicity (carc) potential, ecotoxicity (freshwater) potential, and aquatic eutrophication (N) potential. Different sources for uncertainty are evaluated, and the largest drivers for uncertainty are the assumptions embedded into the substitution effects. The results presented should not be interpreted as a blueprint for the increased production of biodiesel but rather as a benchmarking point for the present, actual impact in a well-to-wheels perspective of biodiesel, with options for improving production and use.

Conclusions

Based on this analysis, we recommend investigating additional options and incentives regarding the increased use of rape straw, particularly considering the carbon sequestration issues (from the perspective of potential climate change) of using bioalcohol instead of PC alcohol for the transesterification process.     

Changes in water content of two agricultural soils does not alter labile P and C pools

Aims

An incubation study was conducted to investigate how changes in soil water content affect labile phosphorus and carbon pools, mineralisation patterns and microbial community composition.

Methods

Two soils from different climatic histories were subjected to four long-term (15 weeks) soil water regimes (constant field capacity (m); 3 dry-rewet (DRW) cycles evenly spaced (intermittent, int); 3 DRW cycles with a shorter interval after a long dry period (false break, fb); constantly air-dry (d)) (incubation period 1). In the subsequent incubation period 2, a set of cores from each treatment were subjected to one DRW cycle (air-dry for 7 day; field capacity for 14 day) or maintained at field capacity.

Results

Long-term soil water regime altered soil respiration with the largest CO₂ pulse occurring in soil with the longest dry period. However, changing the distribution of the 3 DRW events within incubation period 1 (int/fb) did not alter cumulative CO₂. In addition, DRW during incubation period 2 did not affect cumulative CO₂ in either treatment (m, int, fb, d) (except for Hamilton int). Our results show that carbon and phosphorus availability and the size and community composition of the microbial biomass were largely unaffected by fluctuating soil water content.

Conclusions

Changes in soil water content altered respiration, phosphatase activity and microbial C:P ratio and indicate physiological and/or functional changes in the microbial community. However, it appeared that these would have little impact on plant P availability.     

Vehicle manufacturing water use and consumption: an analysis based on data in automotive manufacturers’ sustainability reports

Purpose

The goal of this study is to develop an estimate of water use and consumption in automotive manufacturing to enhance the data quality of vehicle life cycle assessments that include life cycle water impacts. A benchmark is developed to compare water resources across manufacturing and nonproduction-related manufacturing processes, including an indication whether indirect water consumption due to electricity generation is significant.

Methods

Data from 12 original equipment manufacturers’ (OEM’s) sustainability reports are examined for the years 2006 to 2010. Distinctions are made between “water use” and “water consumption.” These factors are divided by total reported production to develop use and consumption values in cubic meter/vehicle for comparison. Additionally, total energy consumption is converted to indirect water consumption based on the water consumed in the generation of electricity for the electricity grid mix.

Results and discussion

Excluding outliers, average direct water use is 5.20 and 5.95 m³/vehicle for manufacturing and company-wide activities, respectively, with corresponding standard deviations of 1.42 and 1.20 m³/vehicle. Average direct water consumption was calculated to be 1.25 and 4.29 m³/vehicle for manufacturing and company-wide activities, respectively, with corresponding standard deviations of 0.52 and 1.56 m³/vehicle. Average indirect water consumption due to electricity consumption is found to be 2.21 m³/vehicle. Variability arises through different understandings on the words “consumption” and “use,” reporting continuity between years and in classification of data as it relates to manufacturing, nonmanufacturing, or company-wide activities.

Conclusions

These water values show that needs vary widely across OEMs. Additionally, the magnitude of the indirect water consumption results indicates that OEMs should focus on both indirect and direct water consumption to reduce their overall water footprint. The results also highlight the potential for significance and variability in indirect water consumption, in particular for “cradle-to-gate” type of impact assessments, dependent on electricity generation water consumption assumptions. It is hoped that with the introduction of water reporting standards like the International Organization of Standardization 14046, manufacturers will provide a more comprehensive summary of their water use and consumption in the future.     

Water scarcity footprint of primary aluminium

Purpose

The cradle-to-gate water scarcity footprint (WSFP) of primary aluminium has been determined for global aluminium including China (GLO) and global aluminium excluding China (RoW). It consists of the following:

• the direct WSFP, based on the freshwater consumption data collected by the IAI from global bauxite mines, alumina refiners and aluminium smelters and the local water scarcity index (WSI) of each plant, and
• the indirect WSFP which has been calculated using data collected by thinkstep on the freshwater consumption of the different ancillary materials, of the fuel and of the electricity needed for the production of alumina and aluminium and the relevant water scarcity indexes.

Methods

The calculation of the direct WSFP follows the requirement of ISO 14046 to aggregate data of sites at locations with different water scarcity after multiplication with the local water scarcity index.For the indirect WSFP, regional averages of the water consumption and water scarcity index were used for an initial screening study to determine fields for further investigation. Results of this study demonstrate that data on evaporation of water from reservoirs of hydropower plants has an extremely high contribution to the indirect WSFP of primary aluminium (79 % of the GLO value and 92 % of the RoW value).Therefore, a plant-by-plant approach was applied for hydropower which considers the net freshwater consumption of the hydropower reservoirs and uses the local water scarcity index of each power station, individually, for the calculation of the generic WSFP of the country or region. A special treatment has been given to some multipurpose reservoirs which typically have a beneficial effect on water scarcity, i.e. they have a negative WSFP if seasonal water scarcity indices are used.

Results and discussion

With this approach, the WSFP of primary aluminium has been calculated as follows:

• 18.2 m³ H₂Oe./tonne for global primary aluminium (GLO);
• 9.6 m³ H₂Oe/tonne for global primary aluminium, excluding China (RoW).

Conclusions

In order to avoid distorted results of water footprint studies, in depth analysis of identified hotspots in water consumption is necessary, in this case the plant-by plant approach, in accordance with ISO 14046. Data providers are encouraged to facilitate such analysis by improving the accessibility of such detailed data.

     

Effects of drip irrigation on deep root distribution, rooting depth, and soil water profile of jujube in a semiarid region

Aims

Aimed to understand how soil water was depleted by deep roots, the effects of drip irrigation and stand age on the deep root distribution, rooting depth, and soil water profile dynamics were investigated in a jujube (Ziziphus jujube Mill. CV. Lizao) plantation.

Methods

A soil coring method with a LuoYang shovel was used for sampling until no more roots were found.

Results

It showed that the maximum fine rooting depth (<2 mm in diameter) increased with stand age and it extended deep into the soil rapidly during the first 4 years, but more slowly in the subsequent 4 years. The maximum rooting depth reached 5 m in a 9-year-old jujube plantation, but it stabilized and did not increase thereafter. However, it was 10 m in a 12-year-old jujube plantation that lacked irrigation.

Conclusions

We found that the application of 33.3 mm of irrigation water (equivalent to 7 % of the local annual precipitation) could halve the maximum rooting depth, thereby reducing deep soil water depletion. Our results showed that a low-volume water supply reduced the maximum rooting depth in jujube and prevented the depletion of the deep soil water. Appropriate drip irrigation is an effective water management strategy for sustainable artificial forest development in semiarid regions.     

Biogenic ethylene promotes seedling emergence from the sediment seed bank in an ephemeral tropical rock pool habitat

Background and aims

Ethylene has been increasingly implicated as a regulatory mechanism in plant germination, growth, and development, and is produced from the sediments of freshwater habitats. In this paper, we analyse the production and origin of ethylene from ephemeral freshwater rock pool sediments, and explore the role of ethylene in regulating seedling emergence from the seed bank.

Methods

The production of ethylene from rock pool sediments subjected to variable moisture content and antibiotic treatments was assessed through gas chromatography, and the role of ethylene in regulating seedling emergence was determined by seedling emergence assays and seed germination experiments.

Results

Biogenic ethylene production from rock pool sediments occurred rapidly (3–6 h) following inundation, with the majority of seedling emergence occurring between 36 and 72 h. Inoculation of sediments with streptomycin and amphotericin B resulted in significantly reduced ethylene production (up to 60 % and 84 % respectively), and completely inhibited seedling emergence. Additionally, the exposure of dormant seeds to ethylene resulted in significantly increased seed germination percentage in five out of six rock pool species.

Conclusions

Biogenic ethylene production may play an important role in regulating seed dormancy and the timing of seedling emergence from the sediment seed bank following inundation events in rock pools and other freshwater aquatic communities.     

Methane and nitrous oxide emissions from direct-seeded and seedling-transplanted rice paddies in southeast China

Background and aims

The rice production is experiencing a shift from conventionally seedling-transplanted (TPR) to direct-seeded (DSR) cropping systems in Southeast Asia. Besides the difference in rice crop establishment, water regime is typically characterized as water-saving moist irrigation for DSR and flooding-midseason drainage-reflooding and moist irrigation for TPR fields, respectively. A field experiment was conducted to quantify methane (CH₄) and nitrous oxide (N₂O) emissions from the DSR and TPR rice paddies in southeast China.

Methods

Seasonal measurements of CH₄ and N₂O fluxes from the DSR and TPR plots were simultaneously taken by static chamber-GC technique.

Results

Seasonal fluxes of CH₄ averaged 1.58 mg m^?2 h^?1 and 1.02 mg m^?2 h^?1 across treatments in TPR and DSR rice paddies, respectively. Compared with TPR cropping systems, seasonal N₂O emissions from DSR cropping systems were increased by 49 % and 46 % for the plots with or without N application, respectively. The emission factors of N₂O were estimated to be 0.45 % and 0.69 % of N application, with a background emission of 0.65 and 0.95 kg N₂O-N ha^?1 under the TPR and DSR cropping regimes, respectively. Rice biomass and grain yield were significantly greater in the DSR than in the TPR cropping systems. The net global warming potential (GWP) of CH₄ and N₂O emissions were comparable between the two cropping systems, while the greenhouse gas intensity (GHGI) was significantly lower in the DSR than in the TPR cropping systems.

Conclusions

Higher grain yield, comparable GWP, and lower GHGI suggest that the DSR instead of conventional TPR rice cropping regime would weaken the radiative forcing of rice production in terms of per unit of rice grain yield in China, and DSR rice cropping regime could be a promising rice development alternative in mainland China.     

Water supply and sustainability: life cycle assessment of water collection, treatment and distribution service

Purpose

The aim of the present paper is to describe the development of a life cycle assessment study of the service of potable water supply in Sicily, Italy. The analysis considers the stages of collection, treatment and distribution of potable water through the regional network, whilst the use stage of water is not included.

Methods

The selection of a methodological pattern coherently with the requirements of an environmental label, such as the EPDs, aims at allowing comparability among different studies.

Results and discussion

The analysis shows the shares of impacts along the life cycle chain, i.e. outputs by well fields and spring groups, purification and desalination plants, water losses in the waterworks, electrical consumption of waterworks systems and impacts of network maintenance. With regard to global warming potential (GWP), the impact of purification plants represents a 6–7 % share of the total, whilst desalination is at 74 %. Water losses in the waterworks show an impact of 15–17 %; the contribution owing to electrical consumption of waterworks systems and network maintenance results to be 3 %. Desalination plants represent the major contribution to all impact categories considered.

Conclusions

In respect to management issues, the most relevant impact categories resulted to be GWP, non-renewable energy resources and water consumption. Since the results for non-renewable energy resources are strictly connected to GWP emissions, carbon footprint and water footprint can be profitably used as single-issue indicators without the risk of burden shifting in studies aiming to evaluate the impact of potable water distribution.