Tomatoes Grown in a Highly Lead Contaminated Soil Are Likely Safe To Eat, New Study Finds

Tomatoes are probably safe to eat, even when grown in severely lead-contaminated soils, according to new studies in Chicago private gardens.

Urban agriculture is flourishing, yet lead is frequently a hidden threat present in urban soils.

An urban agricultural hotspot like Chicago had consistently high lead levels in its soils, according to a recent University of Illinois research.

Tomatoes are safe to eat?

(Photo : Josephine Baran/Unsplash)

According to Andrew Margenot, assistant professor in the Department of Crop Sciences at the University of Illinois and co-author of the study, "There was so little lead accumulation in the fruits, we estimate the average adult male would have to eat almost 400 pounds of tomatoes per week to reach toxic levels," as per ScienceDaily.

Scientists are unsure how vegetables and other crops take up and collect lead in real-world situations.

Roma tomatoes were grown in Chicago backyards by Margenot and co-author George Watson on soil that had lead concentrations between 77 and 1206 parts per million (ppm), which is more than the Illinois EPA's 400 ppm threshold for inhalation danger and higher than the 21 ppm limit of background lead.

When the soil was treated with different phosphorus-based treatments that have been demonstrated to lower lead absorption by people via dust inhalation or particle ingestion routes, the researchers intended to compare how much lead ended up in the fruit with and without soil treatment.

In order to reduce soil lead for human consumption, the EPA advised phosphate fertilizers like triple super phosphate (TSP) at high application rates.

However, stakeholders informed Watson and Margenot that they preferred an organic matter amendment.

Unfortunately, none of the changes reduced the lead content of the tomatoes.

The amendments had no discernible impact since lead absorption by plants into tomato fruits was already so minimal, even in heavily polluted soil.

The average tomato lead concentration across locations was 0.01 ppm in 2019 and 0.13 ppm in 2020, to give some statistics.

Both numbers are well below the Food and Agriculture Organization's (FAO) 1.6 ppm maximum permissible level for tomatoes.

The researchers were puzzled by the variance between study years, even though lead levels stayed extremely low during the course of the two-year trial.

The phosphorus treatments examined in the study, according to Margenot, may not have had much of an impact on the absorption of lead by tomatoes, but they nevertheless showed promise for lead consumption by direct inhalation and ingestion.

He advised that we should pay more attention to phosphorous and regional sources like biosolids if we want to steadily lower the danger of lead consumption and inhalation throughout the city.

In Chicago, biosolids are generated locally, and there are initiatives to get them into the hands of consumers.

So, this would be one nice resource in the city if we're talking about cheap ways to deal with lead.

Also Read: Genetically Modified Tomatoes Might Be a New Source of Vitamin D

Lead in plants and soil

Lead-based paints were formerly used to paint many homes today; unless the paint was removed, it will still be present beneath layers of more recent paint, as per PlantProbs.net.

Several alloys, flashing, solder, and certain batteries all include lead.

Fossil fuel burning releases lead, and other industrial processes also create or release lead.

If soil is subjected to any of these elements or procedures, or if water discharge from these elements penetrates the soil, lead contamination may result.

Contamination with lead may result from mining activities.

Keep in mind that lead-contaminated paint chips frequently pollute the soil within a meter of homes and garages.

Due to prior exposure, even buildings with all lead paint removed may contain lead-contaminated soil in this location. Lead in the soil does not biodegrade and does not readily drain.

If food is grown on lead-affected soil, it may become polluted with lead. Lead is hazardous to plants in a number of ways and may stay in the soil for up to 2000 years.

It adversely affects water and protein content and severely hinders seed germination, root and plant growth, seedling development, transpiration, and chlorophyll synthesis.

Although most of the lead that plants absorb concentrates in their roots, the effects of lead are felt throughout the entire plant.

Lead can have indirect impacts on a range of plants in addition to its direct harmful effects. Lead may destroy soil fungus and bacteria at quantities of 10000-40000 mg/kg.

This in turn hinders the breakdown of organic matter, which restricts the recycling of nutrients and, in turn, the growth of many plants.

Lead can skew the kinds of bacteria present at doses between 500 and 1000 mg/kg. This may have an impact on the kinds of plants that thrive in a specific environment.

Related article: Tomatoes Emit Natural Signal to Warn Other Plants When Attacked by Insects