Earthworm Health Hurt by Nanoparticles in Soil in Alterra Study

Nanoparticles, small-scale materials being developed for uses ranging from sun screen to drug delivery, were shown to damage the health of earthworms in a study by Dutch research institute Alterra.

Exposure to soil laced with carbon nanoparticles showed a “significant” effect, including slower population growth, increased mortality and tissue damage, according to a doctorate study by Merel van der Ploeg.

Nanotechnology deals with matter on a scale comparable to the diameter of a strand of DNA, where materials can work differently when it comes to things like chemical reactions and electrical conductivity. Scientists are using those properties to come up with new cancer treatments, make lighter and stronger materials, and develop alternative energies.

“We saw an effect on the growth of juveniles, mortality and population growth,” said Nico van den Brink, co-promoter of Van der Ploeg’s thesis. “We also saw effects on the integrity of the skin and intestinal wall, which were eroded.”

The study looked at earthworms because they’re a good indicator of soil health, according to Van der Ploeg. The worms hasten decomposition by consuming dead plant material, and their burrowing helps to aerate soil and admit water, according to the website of the Natural History Museum in London.

Highest Dose

The researchers compared the health and growth of earthworms in soil laced with various concentrations of carbon and silver nanoparticles with worms in regular soil. Worms that had the highest dose of 154 milligrams of carbon nanoparticles a kilogram (2.2 pounds) of soil produced about 40 percent fewer cocoons than worms in regular soil, the study showed.

“The same characteristics which make nanoparticles useful in many products, such as chemical reactivity and persistence, cause concern about their potential adverse health effects,” Van der Ploeg wrote. “The present thesis demonstrated hazards of exposure of the earthworm L. rubellus to the nanoparticles.”

A lack of reliable methods to measure nanoparticle levels in soil means that the study results can’t be translated to field conditions yet, according to the researcher.

To contact the reporter on this story: Rudy Ruitenberg in Paris at rruitenberg@bloomberg.net

To contact the editor responsible for this story: Claudia Carpenter at ccarpenter2@bloomberg.net

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