Lichens Used as Monitors of Atmospheric Pollution Around Agadir (Southwestern Morocco)—A Case Study Predating Lead-Free Gasoline

Abstract

More than 30 epiphytic lichens, collected in Agadir (Morroco) and along a 150-km transect from the Atlantic Ocean eastward, were analyzed for their metal content and lead isotopic composition. This dataset was used to evaluate atmospheric metal contamination and the impact of the city on the surrounding area. The concentrations of Cu, Pb, and Zn (average±1 SD) were 20.9±15.2 μg g −1 , 13.8±9.0 μg g −1 , and 56.6±26.6 μg g −1 , respectively, with the highest values observed in lichens collected within the urban area. The 206 Pb/ 207 Pb and 208 Pb/ 207 Pb ratios in the lichens varied from 1.146 to 1.186 and from 2.423 to 2.460, respectively. Alkyllead-gasoline sold in Morocco by the major petrol companies gave isotopic ratios of 206 Pb/ 207 Pb=1.076-1.081 and 208 Pb/ 207 Pb=2.348-2.360. These new, homogeneous values for gasolinederived lead improve and update the scarce isotopic database of potential lead sources in Morocco, and may be of great value to future environmental surveys on the presence of lead in natural reservoirs, where it persists over time (e.g., soils and sediments). The interest of normalizing metal concentrations in lichens to concentrations of a lithogenic element is demonstrated by the consistency of the results thus obtained with lead isotopic ratios. Leaded gasoline contributed less than 50% of the total amount of lead accumulated in lichens, even in areas subject to high vehicular traffic. This strongly suggests that the recent banishment of leaded gasoline in Morocco will not trigger a drastic improvement in air quality, at least in Agadir.

Investigation of spatial and temporal metal atmospheric deposition in France through lichen and moss bioaccumulation over one century

“…6ab) and historical (n = 17, Fig. 6c-d) forested areas (Doucet and Carignan, 2001;Monna et al, 2012;LeGalley et al, 2013). In Fig.…”

Lead Content of Lichens in Metropolitan Harare, Zimbabwe. Air Quality and Health Risk Implications

“…There is very close statistical relationship between the accumulated heavy metals in lichens and the heavy metal pollution measured in air (Monna et al 2012 ;Bajpai et al 2011;Herzig 1993;Sloof and Wolterbeek 1998). Lichen species develop structural changes in response to air pollution that may include reduced photosynthesis and bleaching.…”

Speciation of organometallic compounds of Hg, Sn, and Pb in the market garden soil in Ngaoundéré (Cameroon)

“…Indeed, a few years ago, alkylleads were still used as an antiknocking agent in petrol in some European countries such as Spain despite its prohibition (Encinar et al 2001;Leal-Granadillo et al 2000;Van Cleuvenbergen et al 1990). The use of these alkyl-leads are also banned in some African countries such as South Africa and Morocco (Monna et al 2006(Monna et al , 2011, but it is likely that these compounds are still used in most of sub-Sahelian Africa. Research has been conducted on the presence of OMC (Bachand et al 2014;Marvin-DiPasquale et al 2013;Cattani et al 2008;Wong et al 2011;Huang et al 2003) and OTC (Heroult et al 2008;Marcic et al 2006;Huang and Matzner 2004a;Huang et al 2003;Bancon-Montigny et al 2000;Hoch 2001;Schnaak et al 1997;Barug and Vonk 1980) in soils, but very few have been conducted on OLC in soils (Winter and Gallert 2004;Huang et al 2003;Chau et al 1997).…”