Characteristics of tree bark as an indicator in high-immission areas

Abstract

1. Studies on indicator characteristics of bark of deciduous trees have been continued by measuring accumulation of Pb, Cd, Ni and Mn in the bark of Fraxinus excelsior at 34 sampling sites over an area of 150 km in the immission area of Frankfurt am Main. 2. Iso-lines of equal Pb-contamination have been found. They include zones of graduated immissions. The pattern of these zones shows an eccentrical orientation and is the result of the distribution of the main traffic roads. A significant correlation of Pb in the bark and traffic congestion has been found. 3. The zones of Cd-contamination stretch from SW to NE. The orientation of these zones is determined by the distribution of the big emittenrs and the centers of heating power in the area and the predominating direction of wind. 4. A correlation between the accumulation of Pb and Cd has been detected. It is less significant than that between pH-value and sulfur content in the bark of trees in former investigations. 5. The distribution of Pb and Mn is antagonistic in the bark of Fraxinus excelsior and parallel in the needles of Taxus baccata. The content of Mn in the bark of Fraxinus is low. It must be accepted that this is partly an effect of elution by sulfur acid-aerosol formation. 6. The strongest accumulation of heavy metal immissions is found in mosses on the ground, mainly in Bryum argenteum. Nevertheless the bark of Fraxinus excelsior has shown consequently its accumulation characteristics as a good immission indicator for heavy metal contaminations by traffic and big emittents.

Mapping aerial metal deposition in metropolitan areas from tree bark: A case study in Sheffield, England

“…To date there have been few published attempts to map the distributions of metals from the analysis of tree bark. One was by Lotschert and Kohm (1978) who drew isarithmic ('contour') maps of Pb and Cd based on samples from 34 ash trees (Fraxinus excelsior) throughout Frankfurt. A similar approach, adopted by Bellis et al (2001) to map airborne emissions in the vicinity of a lead smelter, was based on plotting data on the enrichment in Pb.…”

Mapping airborne lead contamination near a metals smelter in Derbyshire, UK: spatial variation of Pb concentration and ‘enrichment factor’ for tree bark

“…11 Such high concentrations of Pb in bark have been recorded only rarely, and are similar to those reported by Little 12 (250-24 200 mg kg 21 ) in the early 1970s near a smelter complex in Avonmouth, 13 but are far in excess of data for comparable studies. [2][3][4][5][6] Although an inverse relationship between Pb concentration and distance from the smelter was observed (Fig. 1), the values were quite variable, highlighting the anticipated problems of sample collection and standardization as already discussed.…”

“…Tree bark accumulates airborne particulate matter through wet and dry deposition processes and has been employed as a passive biomonitor of environmental contamination, 1 in particular for heavy metals including Pb [2][3][4][5][6] (see Walkenhorst et al 1 for a review). Early studies 1,2 determined Pb concentrations in bark along roads in order to study the extent of vehicular pollution.…”

Poincianella pluviosa as biomonitor of heavy metals in the municipality of Volta Redonda, RJ, Brazil

“…In addition to other services, trees can also act as passive biomonitors since they can be influenced by trace element components of heavy metals (Serbula et al, 2013;Santos et al, 2014;Dadea et al, 2017). In this study, the use of biomonitoring as a tool to identify the distribution of metals in the air has already been widely used (Lötschert & Köhm, 1978;Catinon et al, 2009;Guéguen et al, 2011;Moreira et al, 2016). According to Ukpebor et al (2010), peels with higher roughness have a higher absorption surface in relation to fine peels, and the outer layer contains higher concentrations of heavy metals because they are more exposed to pollution.…”