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community-based resource management,

Nutrient and Energy Cycling Check
As discussed earlier for agricultural and residential/parkland land uses, it was not possible to
complete a nutrient and energy cycling check for uranium.
Off-site Migration Check
When deriving soil quality guidelines for industrial sites, exposure scenarios consider only onsite exposure. Transfers of contaminated soil from one property to another is possible by
environmental occurrences such as wind and water erosion (CCME 2005).
The Universal Soil Loss Equation and the Wind Erosion Equation are utilized to estimate the
transfer of soil from one property to another. The following equation allows us to calculate the
concentration (Ci) in eroded soil from the industrial site that will raise the contaminant
concentration in the receiving soil to equal the residential/parkland guideline within a specific
time frame. If the guideline for industrial sites is found to be above Ci, then neighbouring
properties could potentially become unacceptably contaminated from off-site deposition (CCME
2005). The following equation has been derived to allow the calculation of Ci.
( ) ( ) C
D i
= ×− − ×
C = concentration of contaminant in eroded soil (mg/kg) i
DM = depth of mixing, 2 cm (default)
C = concentration of contaminant in receiving soil after mixing, set equal to the soil quality
guideline for residential/parkland land use (500 mg/kg)
D = depth of deposited material before mixing: 0.14 cm (assuming a deposition rate of
13.9 t/ha and bulk density for the eroded material of 1 t/m
BSC = background concentration of contaminant in the receiving soil (2 mg/kg) (NCRP 1984)
Therefore, using the equations and assumptions above, the concentration of contaminant in the
eroded soil was estimated to be 7116 mg/kg which is greater than the SQGE of 2000 mg/kg for
the industrial scenario. Therefore the industrial SQGE is not changed.
It should be noted that with water or wind erosion, there may be some particle-sorting, with finer
particles (e.g., clay) being eroded more than coarse particles (e.g., sand). The concentration of
uranium sorbed to clay particles is high relative to other coarser particles, and therefore erosion
can lead to concentration enrichment of uranium in eroded soil (Sheppard and Evenden 1992b).
In a study that examined water-erosion of two soils with a 10% slope and contaminated with
uranium, the mean uranium enrichment ratios