Assessing atmospheric particulate matter distribution based on Saturation Isothermal Remanent Magnetization of herbaceous and tree leaves in a tropical urban environment

• Published in: The Science of the total environment 2014-02, Vol.470-471, p.975-982
• Main Authors: Barima, Yao Sadaiou Sabas, Angaman, Djédoux Maxime, N'Gouran, Kobenan Pierre, Koffi, N'guessan Achille, Kardel, Fatemeh, De Cannière, Charles, Samson, Roeland
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Atmosphere - chemistry; Bioindicator; Cote d'Ivoire; Environmental Monitoring - methods; Leaf SIRM; Local air quality; Particulate matter; Particulate Matter - analysis; Plant Leaves - chemistry; Trees - chemistry; Tropical urban
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2013.10.082

Particulate matter (PM) emissions, and the associated human health risks, are likely to continue increasing in urban environments of developing countries like Abidjan (Ivory Cost). This study evaluated the potential of leaves of several herbaceous and tree species as bioindicators of urban particulate matter pollution, and its variation over different land use classes, in a tropical area. Four species well distributed (presence frequencies >90%) over all land use classes, easy to harvest and whose leaves are wide enough to be easily scanned were selected, i.e.: Amaranthus spinosus (Amaranthaceae), Eleusine indica (Poaceae), Panicum maximum (Poaceae) and Ficus benjamina (Moraceae). Leaf sampling of these species was carried out at 3 distances from the road and at 3 height levels. Traffic density was also noted and finally biomagnetic parameters of these leaves were determined. Results showed that Saturation Isothermal Remanent Magnetization (SIRM) of leaves was at least 4 times higher (27.5×10−6A) in the vicinity of main roads and industrial areas than in parks and residential areas. The main potential sources of PM pollution were motor vehicles and industries. The slightly hairy leaves of the herbaceous plant A. spinosus and the waxy leaves of the tree F. benjamina showed the highest SIRM (25×10−6A). Leaf SIRM increased with distance to road (R2>0.40) and declined with sampling height (R2=0.17). The distance between 0 and 5m from the road seemed to be the most vulnerable in terms of PM pollution. This study has showed that leaf SIRM of herbaceous and tree species can be used to assess PM exposure in tropical urban environments. •Spatial variation of PM was determined from leaf magnetic in a tropical urban.•Highest leaf SIRM was found near roads; lower were obtained in residential areas.•The slightly hairy and the waxy leaves showed the highest SIRM.•Leaf SIRM decreased with distance from the road and declined with sampling height.•Leaf SIRM can be used as a bioindicator of ambient PM pollution in tropical urban.