FiRe Session Proposes Plants as Solution to Chemical Toxicity in Humans

By Nick Fritz

We are creating and using record numbers of industrial and agricultural chemicals every year, with little understanding of their side-effects on biological systems. Dr. James “Ben” Brown, Department Head of Molecular Ecosystems Biology at the Lawrence Berkeley National Laboratory explored the unintended but increasingly noticeable consequences of the wide use of these industrial compounds. The session was hosted by David Morris.

The infrastructure currently being used to determine toxicity of new chemicals is sorely lacking, and the subsequent regulation is inadequate.

“We regulate against known compounds,” Brown said. “We don’t have standards for unknown compounds.”

Out of the approximately 100,000 industrial compounds in use across the world today, only around 7 percent have known toxicity profiles. Carbon nanotubes are an example of such a compound. They can be bought inexpensively on the open market. When inhaled, 40 percent of the nanotubes remain in the lungs and cause necrotic lesions.

Another facet of the problem is the process used to determine the toxicity for that 7 percent. The current testing process takes approximately 5 years and $1.5 million per compound to determine toxicity in rodents. A series of “interspecies correction factors” is then applied to determine unhealthy doses in humans. These factors are largely just educated guesses. This scaling creates an over-regulation problem, whereby certain chemicals are billed “toxic” at levels far below their actual toxicity threshold.

To solve these problems, Brown and his team are proposing that prospective toxicology testing may create relevant timescales and more significant interspecies applicability. The idea is that testing can be done across a variety of organisms that represent a broad spectrum of the phylogenetic tree, and are therefore applicable across the entirety of the tree of life.

On a smaller scale, molecular ecosystem biology is attempting to understand how gene regulatory transduce, respond to and ultimately influence both populations and ecologies. In this way, Dr. Brown is trying to replicate very complex microbial systems, like those that exist in acre plots of farmland, in order to better isolate the chemical variable in toxicity testing. If microbial variables can be eliminated from the toxicity testing of chemicals in plants, we could have a much better understanding of the actual effect of the chemical(s) in question.

The Environmental Consortium is just one organization that is advocating internationally for the need for this testing. Using these methods on a large scale would help to dramatically reduce the harm caused by chemical compounds at all levels of the tree of life, from microbe to biome.

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