Atmospheric pollution assessed by in situ measurement of magnetic susceptibility on lichens

MARIÉ, DÉBORA C.; CHAPARRO, MARCOS A.E.; LAVORNIA, JUAN M.; SINITO, ANA M.; CASTAÑEDA MIRANDA, ANA G.; GARGIULO, JOSÉ D.; CHAPARRO, MAURO A.E.; BÖHNEL, HARALD N.

ECOLOGICAL INDICATORS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018 vol. 95 p. 831 - 840

1470-160X

The use of environmental magnetism methods andbiomonitors allows us the development of a low-cost tool for assessingatmospheric pollution through trapped magnetic particulate matter. Suchparticles concentration was monitored in situ, on the lichen?s thallus, using magnetic susceptibility as a pollutionproxy. We studied the magnetic particle distribution on the thallus surfacefrom weekly measurements of in situ magnetic susceptibility κis during 16 months for seven sites. A total of∼8300 measurementswas carried out; and mean overall κis values for each lichen varied between 4.1 and 23.9×10−5SI revealing the influence of different atmosphericpollution sources on Parmotrema pilosum, such as metallurgicalfactories and vehicular emissions. Weekly measurements of κis show areas of magnetic accumulation on the thallusover a period of 60 measurement campaigns. Iron rich spherules and irregularparticulate matter between PM2.5 and PM1.0 were observed by SEM-EDS. A jointanalysis of meteorological variables and magnetic susceptibility shows aninverse relation between this magnetic parameter and temperature, i.e., a trendof decreasing κis values during seasons of higher temperatures whichtend toward higher values of atmospheric mixing height. Precipitation also affectsthe magnetic signal over time, producing decreases in mean values of κis after rainy periods.