Assessing potential impacts of sugarcane production on water resources: A case study in Brazil

Abstract

AbstractSustainability has been considered essential for the future consumption of biofuels in large scale and, thus, assessing the impacts on water resources is one of the priorities. The aim of this study is to assess the potential impacts of sugarcane expansion both on the quality and on the quantity of water resources, but using a publicly available database and well‐established statistic procedures. The case studies were defined in São Paulo state, where the bulk of sugarcane production in Brazil is, and more specifically three regions where significant expansion recently occurred: Palmares Paulista, Pontal, and Ribeirão Preto. Time series of streamflows and precipitations (1974–2011) and water quality parameters (1989–2011) were evaluated using non‐parametric tests for detecting trends and abrupt changes. Quality parameters analyzed were concentrations of potassium, total phosphorus, nitrite, nitrate, ammoniacal nitrogen, total solids, dissolved oxygen, and biochemical oxygen demand. Sugarcane cropping data were correlated with streamflows and water quality parameters. Water quality parameters were analyzed vis‐à‐vis sugarcane production and population growth. Significant impacts due to sugarcane cropping were detected only in the case of the smallest basin. In the three studied regions a significant increasing trend of nitrogen and biochemical oxygen demand was observed, but these results can be explained either by sugarcane–ethanol production or by the discharge of sewage and industrial effluents without appropriate treatment. Based on data availability it was not possible to rigorously determine the contribution of large‐scale production of sugarcane cropping to both the quantity and the quality of water resources. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd