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This article in JEQ

  1. Vol. 30 No. 6, p. 2173-2179
    Received: Jan 8, 2001

    * Corresponding author(s): j-sloan@tamu.edu


Distribution of Mercury in Soil and its Concentration in Runoff from a Biosolids-Amended Agricultural Watershed

  1. J. J. Sloan *a,
  2. R. H. Dowdyb,
  3. S. J. Baloghc and
  4. E. Naterb
  1. a Texas Agricultural Experiment Station, Texas A&M University, 17360 Coit Road, Dallas, TX 75252-6599
    b Dep. of Soil, Water and Climate, Univ. of Minnesota, 1991 Upper Buford Circle, St. Paul, MN 55108
    c Metropolitan Council Environmental Services, 2400 Childs Road, St. Paul, MN 55106


Biosolids applications can significantly increase Hg concentrations in cultivated soils. The objective of this study was to quantify levels of mercury in soils and runoff from a biosolids-amended watershed. The study site was a terraced, cultivated watershed that received cumulative biosolids loadings of 0, 87, or 224 Mg ha−1 between 1974 and 1993. Snowmelt runoff samples were collected from the three treatment areas in the spring of 1995. Soils were collected along transects from the 0 and 224 Mg ha−1 biosolids treatment areas at depths of 0 to 15 and 15 to 30 cm. Mercury analysis of stored, freeze-dried biosolids samples showed that Hg concentrations during the 20-year study ranged from 12.4 mg kg−1 initially to 2.4 mg kg−1 near the end. Soil Hg concentrations were elevated in the surface (0–15 cm) and subsurface (15–30 cm) of the 224 Mg ha−1 biosolids-treated terrace relative to the control. Mercury concentrations in the 0- to 15-cm soil depth ranged from 30 to 50 μg kg−1 for the control terrace and 180 to 390 μg kg−1 for the 224 Mg ha−1 biosolids-treated terrace. Concentrations were lower in the 15- to 30-cm depth. Total Hg concentrations in snowmelt from the control terrace ranged from 9.2 to 27.9 ng L−1 and 19.8 to 44.8 ng L−1 for the biosolids-treated terraces. Most Hg was associated with particulates > 0.45 μm. Mercury concentrations were elevated in grass tissue growing near the watershed's runoff lagoon.

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Copyright © 2001. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.30:2173–2179.