Oil and gas extraction in the western United States generates significant volumes of produced water (PW) that is typically injected into deep disposal wells. Recently, crop irrigation has emerged as an attractive PW reuse option, but the impact on plant immune response is not known. In this study, we conducted a 3-month greenhouse pot study. Spring wheat (Triticum aestivum) was irrigated 3 times a week with 150 mL (∼80–100% of soil water holding capacity) with one of four irrigation treatments: tap water control, 10% PW dilution, 50% PW dilution, and salt water (NaCl50) control containing the same amount of total dissolved solids as PW50 to determine the effect on disease resistance. The wheat leaves were inoculated with either bacterial or fungal pathogens and changes in pathogenesis-related PR-1 and PR-5 gene expression were measured from the leaf tissue. PW50 experienced the largest relative suppression of PR-1 and PR-5 gene expression compared to noninfected wheat, followed by PW10, NaCl50, and the tap water control. A combination of PW contaminants (boron, total petroleum hydrocarbons, and NaCl) are likely reducing PR-gene expression by reallocating metabolic resources to fight abiotic stresses, which then makes it more challenging for the plants to produce PR genes to fight pathogens. This study provides the first evidence that plant disease resistance is reduced due to irrigation with reused PW, which could have negative implications for food security.

Biofuels in Ecuador were born with the purpose of achieving an effective substitution of imports of petroleum derivatives. The objective of this research is to analyze the impact that biofuel production has on water, food, and energy, and its contribution to reducing the growing dependence on fossil fuels in the transportation sector in Ecuador. The analysis focuses on ethanol produced from sugar cane, which is used to produce Ecopaís gasoline. The methodology is composed of three parts. For the first part, Geographic Information Systems were used; for the second, the FAO Penman-Monteith method; and, finally, in the third, the energy consumption was obtained through secondary information. As a result, taking the year 2019 as a reference, ethanol became the ninth product with the largest amount of land suitable for agriculture, and the seventh with the most irrigated areas in a country that suffers from malnutrition. Countries with a tropical climate and highly dependent on imports of petroleum derivatives are tempted to implement policies to promote biofuels. However, due to the risks that this renewable fuel represents on food security, other options for reducing its energy dependence should be exhausted.

A data-driven model is used to analyse the global effects of biodiesel on the energy–water–food (EWF) nexus, and to understand the complex environmental correlation. Several criteria to measure the sustainability of biodiesel and four main limiting factors for biodiesel production are discussed in this paper. The limiting factors includes water stress, food stress, feedstock quantity and crude oil price. The 155-country model covers crude oil prices ranging from USD10/bbl to USD160/bbl, biodiesel refinery costs ranging from -USD0.30/L to USD0.30/L and 45 multi-generation biodiesel feedstocks. The model is capable of ascertaining changes arising from biodiesel adoption in terms of light-duty diesel engine emissions (NO, CO, UHC and smoke opacity), water stress index (WSI), dietary energy supply (DES), Herfindahl–Hirschman index (HHI) and short-term energy security. With the addition of potential biodiesel production, the renewable energy sector of global primary energy profile can increase by 0.43%, with maximum increment up to 10.97% for Malaysia. At current crude oil price of USD75/bbl and refinery cost of USD0.1/L, only Benin, Ireland and Togo can produce biodiesel profitably. The model also shows that water requirement varies non-linearly with multi-feedstock biodiesel production as blending ratio increases. Out of the 155 countries, biodiesel production is limited by feedstock quantity for 82 countries, 47 are limited by crude oil price, 20 by water stress and 6 by food stress. The results provide insights for governments to set up environmental policy guidelines, in implementing biodiesel technology as a cleaner alternative to diesel.

Report submitted to Food and Agriculture Organization (FAO) under the project, "Comparative assessment of water usage and impacts arising from biofuel projects in SOUTHEAST ASIAn Countries?, commissioned by the Letter of Agreement No LOA/RAP/2009/38. Thailand and Malaysia are two SOUTHEAST ASIAn countries with rapidly growing biofuel demand. Increasing use of biofuel envisages reducing dependence of petroleum products for transport and mitigating environmental impacts by reducing carbon emissions. It also expects to contribute to rural development and poverty reduction. However, the impacts of expanding production of feedstock for biofuel on water supply are not well understood. This paper assesses the water footprints and impacts of sugarcane molasses and cassava based bioethanol in Thailand, and palm oil based biodiesel in Malaysia. The water footprint of a commodity or service is the water depleted in its life cycle of its production or consumption. The total water footprints of sugarcane molasses and cassava bioethanol production in Thailand are estimated to be 1,646 and 2,304 m3/tonne, respectively, and of palm oil biodiesel in Malaysia is 3,730 m3/tonne. However, the contributions from irrigation are only a small fraction --9.0, 0.7 and 0.3%-- of the total water footprints of molasses and cassava bioethanol, and palm oil biodiesel respectively. In terms of irrigation water use,cassava is a better feedstock for bioethanol production than sugarcane molasses. In Thailand, the total annual irrigation water footprints in bioethanol production --54 million m3 (mcm) for molasses and 15 mcm for cassava-- is only 0.02% of the total renewable water resources. In Malaysia, total annual irrigation water footprint of palm oil biodiesel production is only 0.001% of the total renewable water resources. A significant spatial variation of irrigation water footprints of molasses based ethanol exists across provinces in Thailand, indicating potential for reducing water footprints. The total irrigation water footprints in biofuel production in the future in both countries will also be negligible in comparison to total water availability. However, the impact of wastewater generated in the production processes can have significant impacts on quality of local water resources. A part of the waste water, called 'spent wash', is applied as fertilizer, and over use of it can affect soil and neighboring water resources. The proposed plans on biofuel production in the future can generate more 'spent wash' than that can be used in crop fields as fertilizer. Spent wash has found to have high PH value, temperature, biological and chemical oxygen contents etc. The usual practice of storing spent wash in a pond for a long period near a plant can have detrimental impact on soil, streams' and groundwater quality. In sum, this study concludes that from the perspective of quantity of irrigation water use, the increasing biofuel production does not pose a major problem in Thailand or in Malaysia, and cassava is a better feedstock than sugarcane molasses for bioethanol production. However, the quality of water resources with increasing effluents generated by the biofuel plants could be a major environmental bottleneck to guard against | Upali A. Amarasinghe, Nishadi Eriyagama, Wannipa Soda, 'Growing biofuel demand in Thailand and Malaysia: water use and impacts. Project report submitted to Food and Agriculture Organization (FAO) under the project, "Comparative assessment of water usage and impacts arising from biofuel projects in SOUTHEAST ASIAn Countries?', International Water Management Institute (IWMI), 2014