ORIGINAL ARTICLE Magnetic measurements and pollutants of sediments from Cauvery and Palaru River, India Marcos A. E. Chaparro Æ Ana M. Sinito Æ V. Ramasamy Æ Claudia Marinelli Æ Mauro A. E. Chaparro Æ S. Mullainathan Æ S. Murugesan Received: 5 September 2007 / Accepted: 28 December 2007 / Published online: 31 January 2008 Ó Springer-Verlag 2008 Abstract Rock-magnetic techniques have become a useful tool in environmental issues; in particular, magnetic studies constitute an alternative way to study pollution in different media. The present contribution focuses on magnetic parameters as pollution indicators, especially from their relationship with contents of h\eavy metals. The work was carried out in two Indian rivers located in Tamil Nadu, southern India. Several sediment samples were collected and studied in the laboratory using magnetic techniques, magnetic susceptibility, anhysteric remanent magnetization, isothermal remanent magnetization, and chemical techniques to determine contents of heavy metals. Magnetic mineralogy indicates the predominance of ferri- magnetic minerals; although magnetite-like minerals are the main magnetic carriers, antiferromagnetic minerals can be present as subordinate carriers. Concentration-depen- dent magnetic parameters revealed noticeable differences between both rivers, e.g. magnetic susceptibility is four times higher in Cauvery than in Palaru River. Moreover, such increase can be interpreted as ‘‘magnetic enhance- ment’’ and therefore related to the pollution status. This magnetic enhancement indicated a different pollutant contribution in both rivers, and also, a different spatial distribution along these rivers, where critical (or more polluted) sites were identified. On the other hand, univar- iate and multivariate statistical analyses—e.g. PCoordA, Multifactorial Analysis of distance, PCA and RDA—were examined, revealing a link between magnetic and chemical variables. Among magnetic parameters, the concentration- dependent magnetic parameters (e.g. magnetic suscepti- bility) seem to be the most relevant for this study. Keywords Environmental magnetism  Magnetic enhancement  Multivariate statistical techniques  River sediments  Pollution Introduction Magnetic enhancement occurring in different environments is a term that can involve several processes (Tite and Linington 1975; Mullins 1977; Thompson et al. 1980; Maher 1986), such as, burning, chemical processes, magnetised plus heavy metals particles emission. The latter process is obviously related to pollution, therefore magnetic enhancement can be used in order to assess an environment and estimate its pollution status. Since the 1980s, rock magnetic techniques have been investigated and improved, becoming an auxiliary tool to study pollution issues in different environments. A large number of authors have investigated it obtaining interesting results; among them: Hunt et al. (1984), Beckwith et al. (1986), Strzyszcz (1993), Strzyszcz et al. (1996), Georgeaud M. A. E. Chaparro  A. M. Sinito  C. Marinelli  M. A. E. Chaparro CONICET and Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Pinto 399, CP 7000 Tandil, Argentina M. A. E. Chaparro (&) Centro de Geociencias, Universidad Nacional Auto ´noma de Me ´xico (UNAM), Blvd. Juriquilla No. 3001, CP 76230 Juriquilla, Quere ´taro, Me ´xico e-mail: chapator@exa.unicen.edu.ar; mchaparro@geociencias.unam.mx V. Ramasamy  S. Mullainathan  S. Murugesan Department of Physics, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India 123 Environ Geol (2008) 56:425–437 DOI 10.1007/s00254-007-1180-1