Magnetic monitoring of pollution in the urban area of Tandil City using lichens as bioindicators

MARIÉ, C; CHAPARRO, MARCOS; IRURZUN, M A; LAVORNIA, J; BOHNEL, H; MARINELLI, C; CEPEDA, R; SINITO, A M

San Juan

Congreso; XXVII Reunión Científica de la Asociación Argentina de Geofísicos y Geodestas (AAGG); 2014

Asociación Argentina de Geofísicos y Geodestas (AAGG)

A biomonitor is an organism which has a reaction that can be identified against different adverse influences if there is an alteration of the environment, for example, pollution. Some biological species are unable to adapt ecologically or genetically to the altered environmental condition, hence its absence is an indicator of problems (Hawksworth and Hill, 1984; Nimis et al, 2002).Lichens are known to be sensitive to various pollutants and are considered a good biological indicator of air quality. Thus they are widely used in environmental studies, and recently, in magnetic monitoring (Chaparro et al., 2013).This study focuses on the use of lichen species (Parmotrema pilosum) as biomonitor of pollution and presents a detailed study of magnetic parameters to assess the urban area of Tandil City (Argentina). The main sources of pollution in the urban area are the vehicular traffic and metallurgical industries.The sampling design was a stratified random sampling that encompassed a total of 671 trees. A total of 180 samples of lichens on the bark tree were collected and studied from the selected sites.Magnetic susceptibility, magnetic hysteresis loops, anhysteretic and isothermal remanent magnetization and thermomagnetic measurements were used to determine the magnetic properties of lichen samples. The vegetation material was measured in laboratories from Argentina (IFAS, UNCPBA) and México (CGEO, UNAM).The magnetic mineralogy shows a predominance of magnetite like-phase. The Day?s plot shows that the samples are located in the pseudo-single domain (PSD) region and the thermomagnetic studies (curves M(T)) suggest magnetite as the main magnetic carrier.