(NaturalNews) Vegetable gardens across the United States are contaminated with lead, even those using presumably safe soil from newly made compost, according to a study conducted by researchers from Wellesley College and presented at a meeting of the Geological Society of America.
The most common sources of lead contamination in the United States are still leaded paint and gasoline used before those products were banned. Because lead is a chemical element, it never degrades. It is a powerful neurotoxin that can produce behavioral irregularities or permanent mental retardation.
"Adverse effects from lead can occur at very low levels," warns Robert Ivker in his book Sinus Survival.
"Early symptoms of lead poisoning -- such as nervousness, irritability, headaches, fatigue, muscular problems, constipation, and indigestion -- are hard to pinpoint as lead-related."
Prior research by the Wellesley researchers in cooperation with The Food Project found lead levels above 400 micrograms per gram of soil in 81 percent of 144 backyard gardens tested in the Boston communities of Roxbury and Dorchester. Although there is no safe level of lead exposure, the Environmental Protection Agency has set 400 micrograms per gram as the maximum acceptable threshold.
To remedy the problem, The Food Project installed raised beds filled with freshly composted soil in community and backyard gardens across the area. Although these raised beds started with lead levels as low as 110 micrograms per gram, monitoring showed that over the course of four years these levels rose to an average of 336 micrograms per gram.
In their most recent study, the researchers conducted detailed monitoring and chemical analysis of the raised beds to determine where the lead contamination was coming from. Based on that analysis, the researchers believe that wind and rain are transporting the lead from other contaminated sites.
The good news is that the types of lead being found are poorly absorbed by the human body. More importantly, lead exposure can be dramatically reduced simply by discarding the top inch or two of soil from a raised garden bed every year.