Magnetic parameters, trace elements and multivariate statistical studies of river sediments from the south eastern India: a case study from Vellar River.

MARCOS A.E. CHAPARRO; MAURO A.E. CHAPARRO; P. RAJKUMAR; V. RAMASAMY; ANA M. SINITO

Environmental Earth Sciences

Springer-Verlag

Lugar: Berlin; Año: 2011 vol. 63 p. 297 - 310

1866-6280

This contribution constitutes a new study ?using magnetic parameters and trace element determinations? of pollutants in river sediments from Tamil Nadu state. The Vellar River covers a total length of about 200 km and flows into the Bay of Bengal. Sediment samples were collected at different sediment depths (up to 90 cm) from 12 sites to investigate their magnetic properties (27 samples) and contents of trace elements (21 out of 27 samples) along the river; as well as, magnetic studies for various grain size fractions (16 sub samples). The magnetic results ?magnetic susceptibility and remanent magnetizations? suggest that the magnetic signal of these sediments is controlled by ferrimagnetic minerals: magnetite-like minerals, and a minor contribution of antiferromagnetic carriers (such as hematite minerals) is also expected. Detailed studies of selected samples showed higher magnetic concentration in finer grain size fractions, and a slightly different magnetic mineralogy. Magnetic concentration-dependent parameters evidenced high values, which, together with the background values, allow us to identify magnetic enhancement at some sites. The Pearson correlation and multivariate statistical studies ?Principal Component Analysis, Canonical Correlation Analysis? supported the relationship between magnetic and chemical variables; in particular, magnetic susceptibility, anhysteretic and isothermal remanent magnetization are closely correlated to Co, Cr, Cu, Fe, V, Zn and the pollution load index. In addition, Principal Coordinate Analysis and Fuzzy C-means Cluster Analysis allowed us to make a classification and get a magnetic-chemical characterization of the data into four groups, and therefore identify critical (possibly polluted) sites from Vellar River.