Lead (Pb) exposure of consumers and the environment has been reduced over the past decades. Despite all measures taken,
immission of Pb onto agricultural soils still occurs, with fertilizer application, lead shot from hunting activities, and Pb
from air deposition representing major sources. Little is known about the intermediate and long-term consequences of these
emissions. To gain more insight, we established a mathematical model that considers input from fertilizer, ammunition,
deposition from air, uptake of Pb by crops, and wash-out to simulate the resulting Pb concentrations in soil over extended
periods. In a further step, human oral exposure by crop-based food was simulated and blood concentrations were derived
to estimate the margin of exposure to Pb-induced toxic effects. Simulating current farming scenarios, a new equilibrium
concentration of Pb in soil would be established after several centuries. Developmental neurotoxicity represents the most
critical toxicological effect of Pb for humans. According to our model, a Pb concentration of ~ 5 mg/kg in agricultural soil
leads to an intake of approximately 10 μg Pb per person per day by the consumption of agricultural products, the dose corresponding
to the tolerable daily intake (TDI). Therefore, 5 mg Pb/kg represents a critical concentration in soil that should
not be exceeded. Starting with a soil concentration of 0.1 mg/kg, the current control level for crop fields, our simulation
predicts periods of ~ 50 and ~ 175 years for two Pb immission scenarios for mass of Pb per area and year [scenario 1: ~ 400 g
Pb/(ha × a); scenario 2: ~ 175 g Pb/(ha × a)], until the critical concentration of ~ 5 mg/kg Pb in soil would be reached. The
two scenarios, which differ in their Pb input via fertilizer, represent relatively high but not unrealistic Pb immissions. From
these scenarios, we calculated that the annual deposition of Pb onto soil should remain below ~ 100 g/(ha × a) in order not to
exceed the critical soil level of 5 mg/kg. We propose as efficient measures to reduce Pb input into agricultural soil to lower
the Pb content of compost and to use alternatives to Pb ammunition for hunting.