Fluoride Biomonitoring around a Large Aluminium Smelter Using Foliage from Different Tree Species

Abstract

In order to study the pollution gradient in the vicinity of a large aluminium productionfacility in Patagonia (Argentina), a passive biomonitoring was performed employingfoliage from three tree species. Primary scope was to identify pollution gradients and toselect suitable tree species which can be used as biomonitor plants in the study area.Therefore, leaves of Eucalyptus rostrata, Populus hybridus and different needle ages of Pinusradiata were collected at different distances from the industry and the fluoride concentrationwas analysed in washed and unwashed samples in order to determine theamount of external fluoride. Washing reduced the F-concentrations by 24, 39 and 51%on average in E. rostrata, P. hybridus and P. radiata, respectively, indicating that speciesspecificcharacteristics determine the accumulation and wash-off of dust-associatedfluorine. F-concentrations varied from 6 to 3652 ppm F in unwashed samples indicatinga steep pollution gradient in the study area. The influence of F-emissions was discerniblein all samples up to a distance of 3500m from the smelter. E. rostrata accumulatedmore fluorine than the other species at equal distance from the emission source. Thepresent study confirms that aluminium smelting results in high F deposition in thestudy area. Establishing a biomonitor network around large emitters is suitable andfeasible to evaluate the efficiency of air control measures.