Abstract
Recent studies have suggested that the residence time of Pb in the forest floor may not be as long as previously thought, and there is concern that the large pulse of atmospheric Pb deposited in the 1960s and early 1970s may move rapidly through mineral soils and eventually contaminate groundwater. In order to assess Pb mobility at a woodland (JMOEC) in south-central Ontario, a stable Pb isotope tracer 207Pb (8 mg m−2) was added to the forest floor in white pine (Pinus strobus) and sugar maple (Acer saccharum) stands, respectively, and monitored over a 2-year period. Excess 207Pb was rapidly lost from the forest floor. Applying first-order rate coefficients (k) of 0.57 (maple) and 0.32 (pine) obtained from the tracer study, and estimates of Pb deposition in the region, current predicted Pb concentrations in the forest floor are 1.5–3.1 and 2.1–5.8 mg kg−1 in the maple and pine plots, respectively. These values compare favorably with measured concentrations (corrected for mineral soil contamination) of 3.1–4.3 mg kg−1 in the maple stand and 2.6–3.6 mg kg−1 in the pine stand. The response time (1/k) of Pb in the forest floor at the sugar maple and white pine plots was estimated to be 1.8 and 3.1 years, respectively. The rapid loss of Pb from the forest floor at the JMOEC is much greater than previously reported, and is probably due to the rapid rate of litter turnover that is characteristic of forests with mull-type forest floors. In a survey of 23 forested sites that border the Precambrian Shield in south-central Ontario, Pb concentrations in the forest floor increased exponentially with decreasing soil pH. Lead concentrations in the forest floor at the most acidic survey sites, which exhibited mor-type forest floors, were approximately 10 times higher (∼80 mg kg−1) than at the JMOEC, and pollution Pb burdens were up to 25 times greater. Despite the rapid loss of Pb from the forest floor at the JMOEC, the highest pollution Pb concentrations were found in the upper (0–1 cm) mineral soil horizon. Lead concentrations in the upper 30 cm of mineral soil were strongly correlated with organic matter content, indicating that pollution Pb does not move as a pulse down the soil profile, but instead is linked with organic matter distribution, indicating groundwater contamination is unlikely.
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References
Benninger L.K., Lewis D.M. and Turekian K.K. 1975. The use of natural Pb-210 as a heavy metal tracer in the river-estuarine system. ACS Symp. Ser. 18: 201–210.
Berg B. and Matzner E. 1997. Effect of N deposition on decomposition of plant litter and soil organic matter in forest systems. Environ. Rev. 5: 1–25.
Berg B.Ekbohm G., Soderstrom B.andStaaf H. 1991. Reduction of decomposition rates of Scots pine needle litter due to heavy-metal pollution. Water Air Soil Pollut. 59: 165–177.
Berg B., McClaugherty C. and Johannson M. 1993. Litter mass-loss rates in late stages of decomposition at some climatically and nutritionally different pine sites. Long term decomposition in a Scots pine forest. VIII. Can J. Bot. 71: 680–692.
Billet M.F., Fitzpatrick E.A. and Cresser M.S. 1991. Long-term changes in the Cu, Pb and Zn content of forest soil organic horizons from north-east Scotland. Water Air Soil Pollut. 59: 179–191.
Bindler R., Brannvall M.-L., Renberg I., Emteyrd O. and Grip H. 1999. Natural lead concentrations in pristine boreal forest soils and past pollution trends: a reference for critical load models. Environ. Sci. Technol. 33: 3362–3367.
Brannvall M.L., Bindler R., Emteryd O. and Renberg I. 2001. Vertical distribution of atmospheric pollution lead in Swedish boreal forest soils. Water Air Soil Pollut. Focus 1: 357–370.
Bringmark L. and Bringmark E. 2001. Lowest effect levels of lead and mercury on decomposition of mpr layer samples in a long-term experiment. Water Air Soil Pollut. Focus 1: 425–437.
Cotrufo M.F., De Santo A.V., Alfani A., Bartoli G. and De Cristofaro A. 1995. Effects of urban heavy metal pollution on organic matter decomposition in Quercus ilex L. woods. Environ. Pollut. 89: 81–87.
Dillon P.J. and Evans R.D. 1982. Whole-lake lead burdens in sediments of lakes in southern Ontario, Canada. Hydrobiologia 91: 121–130.
Dorr H. and Munnich K.O. 1991. Lead and cesium transport in European forest soils. Water Air Soil Pollut. 57–58: 809–818.
Duchesne L., Ouimet R., Camire C. and Houle D. 2001. Seasonal nutrient transfers by foliar resorption, leaching and litter fall in a northern hardwood forest at Lake Clair Watershed, Quebec, Canada. Can. J. For. Res. 31: 333–344.
Erel Y. 1998. Mechanisms and velocities of anthropogenic Pb migration in Mediterranean soils. Environ. Res. A. 78: 112–117.
Erel Y., Veron A. and Halicz L. 1997. Tracing the transport of anthropogenic lead in the atmosphere and in soils using isotopic ratios. Geochim. Cosmochim. Acta 61: 4495–4505.
Evans R.D. and Dillon P.J. 1982. Historical changes in anthropogenic lead fallout in southern Ontario, Canada. Hydrobiologia 91: 131–137.
Evans R.D. and Rigler F.H. 1980. Calculation of the total anthropogenic lead in the sediments of a rural Ontario lake. Environ. Sci. Technol. 14: 216–218.
Federer C.A. 1982. Subjectivity in the separation of organic horizons of the forest floor. Soil. Sci. Soc. Am. J. 46: 1090–1093.
Friedland A.H. and Johnson A.H. 1985. Lead distribution and fluxes in a high-elevation forest in northern Vermont. J. Environ. Qual. 14: 332–336.
Friedland A.J., Johnson A.H. and Siccama T.G. 1986. Coniferous litter decomposition on Camels Hump, Vermont: a review. Can. J. Bot. 64: 1349–1354.
Friedland A.J., Craig B.W., Miller E.K., Herrick G.T., Siccama T.G. and Johnson A.H. 1992. Decreasing lead levels in the forest floor of the northeastern USA. Ambio 21: 400–403.
Graney J.R., Halliday A.N., Keeler G.J., Nriagu J.O., Robbins J.A. and Norton S.A. 1995. Isotopic record of lead pollution in lake sediments from the northeastern United States. Geochim. Cosmochim. Acta 59: 1715–1728.
Hintelmann H. and Nives O. 2003. Determination of stable mercury isotopes by ICP/MS and their application in environmental studies. In: Cai Y. and Braids O.C. (eds) Biogeochemistry of Environmentally Important Trace Elements. ACS Symposium Series 835, Washington, USA, pp. 321–338.
Jefferies D.S. and Snyder W.R. 1981. Atmospheric deposition of heavy metals in central Ontario. Water Air Soil Pollut. 15: 127–152.
Johansson K., Bergback B. and Tyler G. 2001. Impact of atmospheric long range transport of lead mercury and cadmium on the Swedish forest environment. Water Air Soil Pollut. Focus 1: 279–297.
Johnson A.H., Siccama T.G. and Friedland A.J. 1982. Spatial and temporal patterns of lead accumulation in the forest floor in the northeastern United States. J. Environ. Qual. 11: 577–580.
Johnson C.E., Siccama T.G., Driscoll C.T., Likens G.E. and Moeller R.E. 1995. Changes in lead biogeochemistry in response to decreasing atmospheric inputs. Ecol. Appl. 5: 813–822.
Martin M.H. and Coughtrey P.J. 1987. Cycling and fate of heavy metals in a contaminated woodland ecosystem. In: Coughtrey P.J., Martin M.H. and Unsworth M.H. (eds) Pollution Transport and Fate in Ecosystems. Blackwell Press, UK, pp. 319–336.
Miller E.K. and Friedland A.J. 1994. Lead migration in forest soils: response to changing atmospheric inputs. Environ. Sci. Technol. 28: 662–669.
Nriagu J.O. 1990. The rise and fall of leaded gasoline. Sci. Tot. Environ. 92: 13–28.
Poyat R.V. and McDonnell M.J. 1991. Heavy metal accumulations in forest soils along an urban-rural gradient in southeastern New York, USA. Water Air Soil Pollut. 57–58: 797–807.
Renberg I., Brannvall M.-L., Bindler R. and Emteryd O. 2002. Stable lead isotopes and lake sediments — a useful combination for the study of atmospheric lead pollution history. Sci. Tot. Environ. 292: 45–54.
Sturges W.T. and Barrie L.A. 1989. The use of stable lead 206/207 isotope ratios and elemental composition to discriminate the origins of lead in aerosols at a rural site in eastern Canada. Atmos. Environ. 23: 1645–1657.
Turner R.S., Johnson A.H. and Wang D. 1985. Biogeochemistry of lead in McDonald’s Branch watershed, New Jersey Pine Barrens. J. Environ. Qual. 14: 305–314.
Tyler G. 1978. Leaching rates of heavy metal ions in forest soils. Water Air Soil Pollut. 9: 137–148.
Wang E.X. and Benoit G. 1996. Mechanisms controlling the mobility of lead in the spodsols of a northern hardwood forest ecosystem. Environ Sci. Technol. 30: 2211–2219.
Watmough S.A. and Dillon P.J. 2003. Major element fluxes from a coniferous catchment in central Ontario, 1983– 1999. Biogeochemistry (in press).
Watmough S.A. and Hutchinson T.C. 2003. The quantification and distribution of pollution Pb at a woodland in rural south-central Ontario. Environ. Pollut.. (in press).
Watmough S.A., Hutchinson T.C. and Evans R.D. 1999. The distribution of 67Zn and 207Pb applied to white spruce foliage at ambient concentrations under different pH regimes. Environ. Exp. Bot. 41: 83–92.
Zar J.H. 1984. Biostatistical Analysis. Prentice-Hall, Englewood Cliffs, NJ.
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Watmough, S.A., Hutchinson, T.C. & Dillon, P.J. Lead dynamics in the forest floor and mineral soil in south-central Ontario. Biogeochemistry 71, 43–68 (2005). https://doi.org/10.1007/s10533-005-7661-y
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DOI: https://doi.org/10.1007/s10533-005-7661-y