Arsenic removal from waters by bioremediation with the aquatic plants Water Hyacinth (Eichhornia crassipes) and Lesser Duckweed (Lemna minor) Sandra Alvarado a , Magdiel Guédez a , Marcó P. Lué-Merú b, * , Graterol Nelson a,b , Anzalone Alvaro b , Arroyo C. Jesús c , Záray Gyula d,e a Universidad Nacional Experimental Politécnica ‘‘Antonio José de Sucre” Vice-rectorado de Barquisimeto, Dpto. de Ingeniería Química, Barquisimeto, Edo. Lara, Venezuela b Universidad Centro Occidental Lisandro Alvarado, Decanato de Agronomía, Dpto. Química y Suelos, Núcleo Tarabana, Cabudare, Edo. Lara, Venezuela c Universidad Centro Occidental Lisandro Alvarado, Decanato de Ingeniería Civil, Dpto. de Construcción, Barquisimeto, Edo. Lara, Venezuela d Department of Chemical Technology and Environmental Chemistry, University Eotvoes Lórand, Budapest, Hungary e Hungarian Satellite Centre of Trace Elements Institute to UNESCO, Budapest, Hungary article info Article history: Received 13 July 2007 Received in revised form 20 February 2008 Accepted 21 February 2008 Available online 28 April 2008 Keywords: Bioremediation Arsenic Water Hyacinth (Eichhornia crassipes) Lesser Duckweed (Lemna minor) abstract In this study the removal of arsenic by the Water Hyacinth (Eichhornia crassipes) and Lesser Duckweed (Lemna minor) was monitored under a concentration of 0.15 mg L À1 of the element. Plant densities were 1 kg/m 2 for Lesser Duckweed and 4 kg/m 2 for Water Hyacinth on a wet basis. The arsenic was determined in foliar tissue and water samples by hydride generation atomic absorption spectroscopy. The element was monitored as a function of time during 21 days. No significant differences were found in the bioac- cumulation capability of both species. The removal rate for L. minor was 140 mg As/ha d with a removal recovery of 5%. The Water Hyacinth had a removal rate of 600 mg As/ha d and a removal recovery of 18%, under the conditions of the assay. The removal efficiency of Water Hyacinth was higher due to the bio- mass production and the more favorable climatic conditions. This specie represents a reliable alternative for arsenic bioremediation in waters. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction The arsenic is one of the most toxic elements that could be found in waters (Tseng et al., 2002; Centeno et al., 2002; Katsoyiannis and Zouboulis, 2004; Jain and Ali, 2000); it is considered as carcinogenic (USEPA, 2003; Hughes, 2002) in the A group by The United States Environmental Protection Agency. The presence of the element over the maximum allowed limit of 0.05 mg/L is affecting several coun- tries (USEPA, 2003; Das et al., 2004). The arsenic could be found in water as the result of the dissolution of minerals from volcanic or sedimentary rocks as well from the dilution of geothermal waters (Schmöger et al., 2000). This element is also employed in the man- ufacture of lasers, semiconductors, in the glass industry, pharma- ceutical products, and pigments among other uses (Watts, 1997). In the agriculture the element is used as herbicide and plaguicide in the form of the compounds sodium methyl arsenate, disodium methyl arsenate and dimethyl arsenic acid. It could be considered that the main reason of the water contamination by arsenic is the agriculture and industrial effluents discharge (Schmöger et al., 2000; Watts, 1997; Pickering et al., 2000). The systems for water treatments to reduce the arsenic content in waters are complex. Some methods are the adsorption–copre- cipitation using aluminum and iron salts (Song et al., 2006), adsorption onto activated alumina (Lin and Wu, 2001), activated coal or bauxite (Daus et al., 2004), inverse osmosis, ionic inter- change (Kim and Benjamin, 2004), nanofiltration, among others (Pena et al., 2005; Maity et al., 2005). These methods have high costs and difficult implementation and maintenance. It is neces- sary to evaluate non-expensive simple effective and efficient sys- tems for contaminated water remediation. Some aquatic plants have a high capability to accumulate heavy elements or toxic ones by different mechanisms, and then allow for the purification of high contaminated waters, due to industrial or agrochemical discharges (Maine et al., 2001; Chua, 1998; So et al., 2003). The species Water Hyacinth Eichhornia crassipes and Lesser Duckweed Lemna minor were previously used for decontam- ination or reduction of contaminant levels in water. Kiran et al. (1991) tested four aquatic plants (E. crassipes, Pistia stratiotes, Salvinia rotundifolia and L. minor) and evaluated the re- moval of nitrogen and phosphorus. They observed that E. crassipes has the highest capacity for nitrogen extraction during summer and rainy season, while the phosphorus was more efficiently ex- tracted during summer with the order: Eichhornia, Pistia, and Lemna 0960-8524/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2008.02.051 * Corresponding author. E-mail address: mparra@ucla.edu.ve (M.P. Lué-Merú). Bioresource Technology 99 (2008) 8436–8440 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech