Virtual water is the volume of water used to produce a commodity or service. Hitherto, most virtual water ‘trade’ studies have focused on its potential contribution to saving water, especially in ...water short regions. Very little, however, has been said about the opportunity cost of the associated water. The present research critically evaluates the strategic importance of green water (soil water originating from rainfall) in relation to international commodity trade. Besides having a lower opportunity cost, the use of green water for the production of crops has generally less negative environmental externalities than the use of blue water (irrigation with water abstracted from ground or surface water systems). Although it is widely known that major grain exporters – the USA, Canada, France, Australia and Argentina – produce grain in highly productive rain-fed conditions, green water volumes in exports have rarely been estimated. The present study corroborates that green water is by far the largest share of virtual water in maize, soybean and wheat exports from its main exporting countries (USA, Canada, Australia and Argentina) during the period 2000–2004. Insofar virtual water is ‘traded’ towards water-scarce nations that heavily depend on their blue water resources, green virtual-water ‘trade’ related to these commodities plays a role in ensuring water and water-dependent food security and avoiding further potential damage to the water environments in both importing and exporting countries. This potential of international green virtual-water ‘trade’, however, is constrained by factors such as technology, the potential for further increases in the productivity of soil and irrigation water, the level of socio-economic development, national food policies and international trade agreements.
Agricultural water pollution is a significant challenge in China, a rapidly growing economy with a large agricultural sector. The grey water footprint (WF) is a tool for evaluating freshwater ...pollution. It expresses pollution in volumetric units identifying the pollutant that theoretically needs most water to be diluted to accepted water quality standards. Previous agricultural grey WF studies focused on nitrogen (N) and phosphorus (P), some studies included pesticides. This study assesses grey WFs based on N, P and 1513 pesticide combinations for twelve main crops and two crop categories in 31 Chinese provinces. Grey WFs, including the pesticide component, are far larger than estimated before, dominating total agricultural WFs (green, blue, and grey). The total grey WF of Chinese agriculture (4,900 109 m3 year−1) is determined by pesticides, while grey WFs related to N and P are 450 and 1,500 109 m3 year−1, differences of a factor of eleven and three respectively. The provinces Heilongjiang, Inner Mongolia, Hebei, Henan, and Shandong are hotspots contributing 37 % to the total grey WF. A limited number of pesticides used for maize, vegetables, fruits and potato (Mancozeb a fungicide, Acetochlor a herbicide and Cypermethrin an insecticide) dominate total grey WFs, contributing 80 % to the total grey WF. Eliminating the most polluting pesticides per category and redistributing the remaining ones with a similar function but lower grey WFs reduces national water pollution from agriculture by 64 %. Only five crops, i.e. maize, potato, soybean, rice and wheat, and the two crop categories, vegetables and fruits, contribute 94 % to this reduction. Probably grey WFs could reduce even further with a second elimination and redistribution effort. This study is the first national grey WF assessment related to pesticides in agriculture. It offers valuable insights to farmers and policymakers to enhance water quality in China and beyond.
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•Studies excluding pesticides underestimate crop grey water footprints (WFs)•In China, pesticide-related grey WFs are 11 and 3 times larger than WFs based on nitrogen and phosphorus•A limited number of pesticides applied for specific crops dominate total grey WFs•Small replacements of the most polluting pesticides halve grey WFs•It is crucial to include pesticides in crop grey WF assessments
Water resources use in agriculture is generally quantified in relation to the harvest. In contrast, this paper takes a consumer perspective by assessing water use in relation to the final consumer ...product. The paper analyses the water use related to two products that are typical to Italian consumers: pasta and pizza margherita. We use the water footprint concept as a tool to quantify and localise this water use. The water footprint of a product is the volume of freshwater used to produce the product, measured over the various steps of the production chain. We find that the water footprint of dry pasta made in Italy amounts to 1924
l of water per kilogram of pasta. The water footprint of a 725
g pizza margherita is 1216
l of water. The impacts of the water footprints of pasta and pizza depend on the vulnerability of the water systems where the footprints are located. The impact of the water footprint of pasta is most severe in Puglia and Sicily, where groundwater overexploitation for durum wheat irrigation is common. The impact of the water footprint of pizza is more diverse. It is concentrated in the first step of the supply chain of tomato puree and mozzarella, i.e. in the cultivation of tomatoes and the feed crops of dairy cows. The bread wheat used for the pizza base does not have large impacts. The water footprint impact of the tomato puree on the pizza is concentrated in Puglia (groundwater overexploitation and pollution related to tomato cultivation) and Emilia-Romagna (water pollution). The water footprint impact of mozzarella lies mostly in the effects of water use for producing the feed ingredients for the dairy cows. Mozzarella production further poses a potential threat to water quality, mostly in the Po valley, but this problem seems to be properly regulated, although possibly not fully controlled.
Many environmental studies have shown that a systems approach, including complete supply chains, is relevant for the assessment of the consequences of production and consumption on natural resources. ...This can also be applied to water. Although water consumption also includes water supply chains, often irrigation supply chains are excluded in water footprint (WF) studies. Using information from water management studies on water losses, we propose an improved WF method that includes blue crop WFs and WFs of irrigation supply chains indicating total agricultural blue WFs. A systems approach considering not only irrigation technology but whole water supply chains, also distinguishing between surface and groundwater, is needed to improve efficient blue water use in agriculture. This method is applied to the Pakistani part of the Indus basin that includes the largest man-made irrigation network in the world. The total agricultural blue WF is 1.6 times the blue crop WF. Surface water losses vary between 45 and 49%, groundwater losses between 18 and 21% and are smaller than results from water management studies. Differences between provinces and canal commands are large. The identification of hotspots provides a tool to improve water management. Earlier WF studies might have underestimated agricultural water consumption if supply chains are neglected. More water efficient agriculture should take supply chain losses into account probably requiring water management adaptations, which is more a policy than an agriculture task. WFs of supply chains are also relevant for other sectors, like industry or municipal water supply.
Argentina stands as the leading producer and exporter of olive products in the Americas, with the province of La Rioja as its main productive area. Since the 1990s, the olive grove cultivated area ...and related agro-industry in La Rioja have expanded. However, the resulting wastewater has generally been neglected. The water footprint (WF) provides information about the water volume consumed and polluted by a production process. Since the 1990s, agricultural and agro-industrial activities in La Rioja have experienced substantial growth. This study aims to analyze the generation, quality, and management of Oil Mill Wastewater (OMWW) using the grey WF of chloride and nitrate as an indicator and focusing on two olive mills (OM) in La Rioja. Additionally, it seeks to examine the relationship between the international trade of provincial olive oil and the estimated grey WF. For the diagnosis of OMWW generation, a description of the production process was made coupled with flow and physico-chemical characterization. The total grey WF was 8.69 and 45.5 L water/L olive oil for OM 1 and OM 2, respectively. Nitrate was identified as the critical pollutant. The grey virtual water export related to the export of olive oil was 5569 m3 for OM 1 and 28,000 m3 for OM 2. The provincial grey virtual water export related to olive oil was 161,955 m3 with major trade destinations including Spain, the United States, and Brazil. The article analyses for the first time the grey WF of olive oil industries and assess the related grey virtual water exports. This research represents a step forward in the knowledge of wastewater management in the olive oil sector and facilitates the search for solutions to minimize negative environmental impacts while promoting cleaner production.
A comprehensive framework for revealing the jeopardization between SDGs 2 and 6 is provided in this study. Along with a water footprint (WF) assessment, the 30-years pattern of agricultural WFs and ...its hydro-environmental, social, and ecopolitical (SEP) consequences were quantified for the major food producer regions of Iran, as it is a water-bankrupted country under socioeconomic drought. In addition, the enforced impacts of major water/food-related policies on environmental sustainability were analyzed through an institutional assessment. During 1986–2016, BWS and GWD raised with annual average rates of 5% and 44%, respectively. Consequently, SEP status prospered along with an 18% increase in irrigated area, 198% in added-value by crop production and 5% by staple-crop exports, and 51% in the number of agricultural workers. The Pearson correlation analysis revealed a significant tradeoff between self-supplied food availability and SEP. A 54% increase in food production occurred at the cost of 80% overexploitation in blue water resources and quality degradation. An annual average increase of 1.1% in P/ETo indicates the dominant role of anthropogenic interventions in such deteriorations. The institutional assessment demonstrated that environmental sustainability policies have never been applied as promoting policies to boost self-sufficiency in food production. According to the results, hydrological sustainability requires a transformative vision in national policies to exploit limited water and soil resources while preserving the environment.
Agriculture is the largest fresh water consuming sector, and maize is the most produced and consumed crop worldwide. The water footprint (WF) methodology quantifies and evaluates the water volumes ...consumed and polluted by a given crop, as well as its impacts. In this work, we quantified for the first time the green WF (soil water from precipitation that is evapotranspired) and the green virtual water exports of maize from Buenos Aires province, Argentina, during 2016–2017, due to the relevance of this region in the world maize trade. Furthermore, at local level, we quantified the green, blue (evapotranspired irrigation), and grey (volume of water needed to assimilate a pollution load) WF of maize in a pilot basin. The green WF of maize in the province of Buenos Aires ranged between 170 and 730 m3/ton, with the highest values in the south following a pattern of yields. The contribution of this province in terms of green virtual water to the international maize trade reached 2213 hm3/year, allowing some water-scarce nations to ensure water and water-dependent food security and avoid further environmental impacts related to water. At the Napaleofú basin scale, the total WF of rainfed maize was 358 m3/ton (89% green and 11% grey) and 388 m3/ton (58% green, 25% blue, and 17% grey) for the irrigated crop, showing that there is not only a green WF behind the exported maize, but also a Nitrogen-related grey WF.
Today, human activities are highly dependent on fossil fuels and industrialized forms of agriculture and have reached a level that could damage the Earth’s systems ...
In the year 2011, the FAO estimated that food loss and waste reached one third of the total food produced worldwide. Since then, numerous studies have been published characterizing this problem and ...reflecting on its repercussions, not only social, but also environmental. Food wastage triggers unnecessary greenhouse gas emissions, deforestation or loss of biodiversity. This study aims to quantify the water-related benefits associated with food loss and waste reduction by studying the Food Bank of Navarra (FBN). For this purpose, the water footprint assessment manual has been followed. First, the water footprint of the activities of the FBN has been analysed for the year 2018 (scenario with the FBN). A comparative analysis has been carried out between the scenario with the FBN and a theoretical scenario without the action of the FBN. This has allowed us to highlight the benefits associated with the activity of this entity. The FBN not only avoided the waste of 2.7 thousand tons of food suitable for consumption in 2018, but also avoided the unnecessary use of more than 3.2 million m
of freshwater. As a result of the present investigation, it can be stated that promoting food banks, which avoid food waste, would be an effective way to contribute to the protection and conservation of water resources.
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