ORIGINAL ARTICLE Investigation of calcareous beach sands in the Akumal and Tulum areas for use in constructed wetlands, Eastern Yucatan Peninsula Mark P. S. Krekeler Æ Erin P. Argyilan Æ Jill Lepp Æ Lance E. Kearns Received: 24 August 2008 / Accepted: 23 December 2008 Ó Springer-Verlag 2009 Abstract Constructed wetlands can be a low-cost, eco- logically based technology to locally treat domestic wastewater prior to discharge. Wetland systems imple- mented in the resort village of Akumal in the state of Quintana Roo, in the Yucatan Peninsula of Mexico have been considered moderately successful over approximately 10 years of operation. Yet the wide-scale implementation of constructed wetlands has not occurred in the region nor throughout Mexico due largely to the cost of the crushed aggregate used in these systems. Variation in the geotech- nical and mineralogical properties of 29 samples of local calcareous beach sands collected from the tourist areas of Akumal and Tulum in the Yucatan, Mexico were analyzed and compared to those of crushed aggregate currently used in constructed wetland systems in Akumal. Powder X-ray diffraction on beach sand samples from Akumal and Tulum indicates that the proportion of aragonite varies from 24 to 84%, calcite varies from 7 to 38% and Mg-calcite varied from 8 to 57% compared to crushed aggregate which consists of 0–25% aragonite and 75–100% calcite. Com- pared to crushed aggregate beach sands are unimodal and have better uniformity coefficients, making them a better geotechnical choice than crushed sands with respect to these properties. Grain-size of the beach sands is much smaller compared to that of the crushed aggregate currently used in the constructed wetland systems in Akumal which should enhance the efficiency of the filtration of organic matter and bacteria. The average hydraulic conductivity measurements of 0.010 and 0.016 cm/s for beach sands from Akumal and Tulum, respectively are comparable or less than the average of 0.016 cm/s for crushed aggregate currently used in engineered wetland systems. Yet a combination of high bulk porosity, intragranular pores, and the presence of Mg-calcite observed in beach sands may likely result in higher dissolution rates versus the crushed aggregate. Preliminary assessment suggests that the use of local sand may be a technical, economic, and perceptual enhancement to the systems. Still a careful and thorough analysis of the potential environmental and aesthetic impacts of mining beach sands is necessary. Keywords Calcareous beach sand Á Sedimentology Á Constructed wetlands Introduction The economy of the Yucatan peninsula relies primarily on a large-scale tourism industry that is focused around the scenic coastal environment and the rich ecosystem of the Mesoamerican Caribbean Reef (MACR), the second larg- est barrier reef system in the world (Murray 2007). Yet the success of coastal tourism creates an environmental para- dox as seasonal fluctuations in population create increased M. P. S. Krekeler (&) Department of Geology, Miami University, Hamilton, OH 45011, USA e-mail: krekelmp@muohio.edu E. P. Argyilan Department of Geosciences, Indiana University Northwest, 3400 Broadway, Gary, IN 46408, USA J. Lepp Geology Program, George Mason University, Fairfax, VA 22030, USA L. E. Kearns Department of Geology and Environmental Sciences, James Madison University MSC7703, Harrisonburg, VA 22807, USA 123 Environ Earth Sci DOI 10.1007/s12665-009-0039-z