“…The majority of studies of heavy metals in the Amazon basin have focused on mercury contamination of fish (Malm, Branches, Akagi, Castro, & Pfeiffer, 1995;Dorea, Moreira, East, & Barbosa, 1998;Kehrig, Howard, & Malm, 2008), water (Lacerda et al, 1991;Roulet, Lucotte, Guimarães & Rheault, 2000), river sediments (Mascarenhas et al, 2004;Siqueira & Aprile, 2012), and humans Malm et al, 1995;Lebel et al, 1998;Khoury et al, 2013). Studies on Cr and Cu contamination in the Amazon basin are scarce, with few studies focusing on sediments (Silva, Ramos, & Pinto, 1999), water (Pinto et al, 2009;Lima et al, 2015), and fish (Lima et al, 2015).…”