Neurotoxins have been found to erode intelligence, especially in early developmental stages, with childhood lead poisoning costing the U.S. $50 billion annually, and neurological development disorders affecting 10 – 15 percent of all births.

While the word “neurotoxin” sounds about as dangerous as it is, to the naked eye it is very unassuming. It comes in a bucket of paint, in toothpaste, in a piece of fruit, or a roll of sushi.

It looks like any given store-bought item, but has the potential to be extremely harmful to the growing mind.

What are neurotoxins, and how do they harm the brain?

A neurotoxin by definition is a poisonous complex that acts on the nervous system. These include lead and mercury, along with chemicals found in many herbicides, pesticides, and scented household products.

Though the dose certainly defines the poison, the levels at which toxins are deemed acceptable has changed over time. For example, over the years the CDC has gradually lowered the “safe” threshold of micrograms of lead per deciliter of blood from 60 in 1970 to 5 in 2012.

Studies show that the most harm caused by neurotoxins occur at very early stages of life, when the brain itself is first forming.

As an in depth piece in the Atlantic details, almost all of an adult person’s brain cells are formed by age 2, and once a brain cell dies, it doesn’t grow back.

Arsenic in the cradle

Obviously, prenatal and infant development is crucial to how a person turns out, which is why your mother (hopefully) abstained from cigarettes and alcohol while pregnant.

But perhaps she should have abstained from vegetables treated with insecticide, too: prenatal pesticide exposure leads to shorter pregnancies and lower birth weights, a 2012 study found.

In a study published in 2014, researchers concluded that exposure to neurotoxins in early life can cause permanent and untreatable brain damage, and may result in reduced IQ, behavioral disruption, violence, and criminality.

Even more disturbing is the estimation that neurobehavioral development disorders affect 10 to 15% of births.

The Lancelot Neurology research identified lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene as dangerous to the developing brain in their 2006 studies.

Since then, researchers have added manganese, fluoride, chlorpyrifos, DDT, Tetrachloroethylene, and PDBEs to the list since, speculating that many more remain undiscovered.

In regards to fluoride, another study by Harvard researchers found that children living in areas with highly fluoridated water have “significantly lower” IQ scores than those that do not.

This sort of brain cell damage is not only neurologically costly, but financially.

Researchers estimate that the annual cost of childhood lead poisoning alone (due to reduced IQ and health costs) is $50 billion in the US, and that each dollar invested in hazard control results in a net savings of $181–269 billion.

Reforming the TSCA

According to the Atlantic, most agree that the issue lies not with the toxins themselves, but with the U.S. chemical safety testing system, which is in “dire need of modernization.”

The Toxic Substances Control Act (TSCA), was put in place in 1976 – since then, reforms have been proposed as recently as 2013, but none have passed. Holes in the act have assumed chemicals safe until proven otherwise, causing a lot of backpedaling that could have been prevented if safety legislation were stronger.

Theoretically, chemicals could be screened through a simple cell-based test that would require further testing if petri dish cells showed a toxic reaction.

There is also a testing system called Tox21, which uses robotics to test chemicals rapidly on a large scale.

The science and technology are certainly there. Unfortunately, the legislation that would require their usage – resulting in saved lives and money – has not caught up just yet.

Cover image courtesy of mamihod via Flickr, edited by Curiousmatic with Wikimedia Commons symbols for Chlorpyrifos, Arsenic, Mercury, Toluol, and Lead. “Caution” photo courtesy of Horia Varlan via Flickr, modified by Curiousmatic.