Long-term simulation of lead concentrations in agricultural soils in relation to human adverse health effects

Abstract

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.

Physical, chemical and biological characteristics of clays from Durban (South Africa) for applications in cosmetics

“…Fortunately, red and white clay samples are free of the elements as toxic as Arsenic (As), Mercury (Hg), Cadmium (Cd) and Selenium (Se), except for Lead (Pb), which was detected below permissible levels (200 ppm) at 27 and 16 ppm, respectively. 57 Moreover, red and white clay samples contained 119 and 159 ppm levels of Titanium (Ti), 240 and 570 of Vanadium (V), 130 and 560 ppm of Chromium (Cr), 1730 and 153 ppm of iron (Fe), 340 60 and 29 ppm of Zinc (Zn), respectively. Manganese (Mn) and Nickel (Ni) were only detected in red clay, 850 and 340 ppm, respectively.…”

Phytomanagement of a Lead Polluted Shooting Range Using an Aromatic Plant Species and Its Effects on the Rhizosphere BacteRial Diversity and Essential Oil Production

“…In addition, cereal products, grains and vegetables (especially potatoes and leafy vegetables) are the most important contributors to the Pb dietary exposure in the general European population [9]. In this context, the transfer of Pb into the food chain is a risk that must be taken into consideration [10], as many shooting range areas are used as meadowland after being decommissioned or during non-shooting periods, and some are even used for the production of food crops [11,12].…”

Phytomanagement of a Lead-Polluted Shooting Range Using an Aromatic Plant Species and Its Effects on the Rhizosphere Bacterial Diversity and Essential Oil Production

“…Plants 2022, 11, 3024 2 of 10 many shooting range areas are used as meadowland after being decommissioned or during nonshooting periods, and some are even used for the production of food crops [11,12].…”