You dig a hole and put the soil in a large pail. The hole measures 12x13 inches wide and 10 inches deep. The soil in the pail weighs 80 pounds. What was the bulk density of the soil in g/cm^3 ?© BrainMass Inc. brainmass.com October 24, 2018, 10:06 pm ad1c9bdddf
For the calculation of density, units to be converted into cm & ...
The density of soil can be calculated provided mass and volume of the soil is known. This solution illustrates this and includes the necessary calculations.
Migration of Pesticide from Soil to Groundwater
The following percentages of three pesticides added to a soil remained after increasing times.
Time (days) Diazinon % Benefin % Terbutol %
0 100 100 100
15 18.7 no data no data
30 1.50 57.5 94.3
60 0.30 29.0 80.2
90 0.01 14.5 73.7
180 0.01 7.50 51.3
1) Fit the decomposition data for each of these pesticides to a standard exponential decay function (linear form) and show results graphically.
Nt = N0(1/2)t/t1/2
2) Calculate the decomposition half-life of each pesticide.
3) Draw the chemical structures of each pesticide and suggest a chemical explanation for the relative persistence of these chemicals in soil.
4) Calculate diazinon Kd for a soil with 5% organic matter assuming soil minerals have no tendency to absorb this pesticide.
5) Use this Kd to determine how many years it would take for diazinon to migrate from soil surface into shallow groundwater at 2 m depth (bulk density 1.3 g/cm3, porosity 0.45). Rainfall is 90 cm and evapotranspiration is 40 cm.