Distribution and fractionation of heavy metals in pairs of arable and afforested soils in Denmark

Abstract

Summary Afforestation of sandy arable soils in northern Europe is likely to lead to an increase in the soil's acidity and changes in the behaviour of the organic matter, and this might affect the ability of the soil to retain heavy metals. It is important to assess the impact of such a change in the land use on the solubility of the heavy metals and to assess the risk of leaching to surface‐ and groundwater and the possible entrapment of heavy metals in the tree canopy. The impact of afforestation was assessed by excavating soil profiles in adjacent 34‐year‐old Norway spruce stands and arable plots at four different sites. We found that after 34 years the pH had decreased and cations were depleted in the topsoil under forest. The aqua regia‐extractable heavy metals were determined, and the heavy metal binding within the soil was assessed using a modified version of the BCR (Community Bureau of Reference) sequential extraction procedure. Higher contents of heavy metal were found in the arable plots in the loamy sand soils. Cadmium was found only in the most mobile fractions. The content of Pb in the subsoil was strongly correlated with the clay content, but not in the topsoil, which suggested that Pb had been added to the topsoil. We found strong correlations between the clay content and the Cu, Ni and Zn in the residual fraction, leading us to conclude that much of the Cu, Ni and Zn is of geological origin. No significant differences in the heavy metal fractionation between forest and arable soil were found, presumably because 34 years of different land use is not long enough to produce such differences.

Associations of cadmium, zinc, and lead in soils from a lead and zinc mining area as studied by single and sequential extractions

“…Relatively strong associations of Pb with FeMn oxide-bound fraction have also been reported by Levy et al (1992); Ramos et al (1994); Xian (1987) in polluted soils; Andersen et al (2002) in arable soils and Pardo et al (1990); Corsi and Landim (2002) in sediments and Clevenger (1990) in mining wastes, Wang et al (1998) and Stone and Marsalek (1996) in urban dusts.…”

Quantitative Comparison of Heavy Metals and As Accumulation in Agricultural and Forest Soils near Bowling Green, Ohio

“…In addition to atmospheric deposition, the anthropogenic input of heavy metals in arable land can be enhanced by agricultural practices such as use of pesticides, herbicides, chemical fertilizers, or the application of sewage sludge (Merrington et al 2003;De Temmerman et al 2003). The use of mineral fertilizers, such as phosphate and lime, and animal manure can increase soil heavy metal contents (De Temmerman et al 2003;Andersen et al 2002), as can the application of sewage sludge from waste water treatment facilities (Stephenson and Lester 1987).…”

Exposure assessment of heavy metals pollution enriched in core sediment samples of river Nile, Aswan, Egypt

“…2) indicates that the Cd present in these so-called unpolluted soils is of anthropogenic origin (Andersen et al 2002). The vertical distribution patterns for most studied metals show that, the levels are generally low and do not indicate any significant anthropogenic input, thus are derived predominantly from natural sources lithologic material.…”