So it turns out that perchlorate, a chemical compound used in rocket fuels, fireworks, fertilizers, food packaging and many other industrial materials, seeps into groundwater–the very source of our drinking water. Why is this a problem? Perchlorate has been demonstrated in scientific studies as harming fetal brain development. It has also been shown to present a serious threat to liver and kidney health, as well as being linked to cancer and male reproductive health problems. Of particular concern, perchlorate has also been linked to thyroid problems and is thought to contribute to health issues in humans such as hypothyroidism, the decreased production of hormones from the thyroid gland, which can impact development and lead to a host of lifelong health problems for children and adults alike. For years now, governmental regulators have operated within a “safe” level established for how much perchlorate could exist in our drinking water. The problem is, scientists have just discovered that perchlorate is many times more dangerous to human health than previously thought, making the so-called “safe” level the regulators previously established actually quite dangerous to our health and well-being–as much as 10 times as dangerous.
The Basics: Toxic Chemical Perchlorate Harms the Thyroid
If it has been awhile since you were in college you might have to reach back into your memory bank to remember the particulars, but at the basic level, iodide (the negatively charged form of the element iodine), helps the thyroid make hormones that are essential to the body’s regulation of metabolism, temperature and other important functions. As it turns out, the toxic chemical perchlorate blocks a main route by which iodide enters thyroid cells.
Thyroid cells control the incoming flow of iodide by using a protein channel called the sodium/iodide symporter, also known as the Na+/I- symporter or NIS. Like other cellular transport systems, a “lock-and-key” approach is used to move iodide, with NIS acting as the lock and sodium as the key. Sodium fits into NIS at two binding sites to unlock the channel, enabling iodide to pass through and accumulate inside a thyroid cell.
The scientists determined that perchlorate blocks the channel by latching onto the NIS protein and changing its shape. Less sodium binds to the misshaped channel, thereby significantly lowering the amount of iodide that can be moved inside thyroid cells.
Next, the researchers studied how varying concentrations of perchlorate affects iodide transport by first growing thyroid cells that expressed the gene SLC5A5, which encodes the instructions for building NIS channels. Next, perchlorate and radioactive iodine were placed outside of some of the cells and just radioactive iodine outside the others. And then the researchers tracked how much glowing iodide was allowed to enter the cells in both groups. They found that there was much less iodide inside thyroid cells treated with perchlorate than in untreated ones, even at very low concentrations of the chemical.
Toxic Chemical Perchlorate in Our Drinking Water is Okay, Says the U.S. Government
Unfortunately, in May 2020 the U.S. Environmental Protection Agency (EPA) ruled not to regulate the amount of perchlorate that can be allowed in our drinking water. This is great news for those benefiting from increased corporate profits like board members and investors holding corporate industry stocks, but seriously bad news for the rest of us living in the U.S. who want to minimize exposure to toxins. As the findings from the new study strongly suggest that this toxic environmental pollutant is far more hazardous than previously thought, we can only hope the public will pressure their representatives to get this decision reversed.
Journal Reference: Alejandro Llorente-Esteban, Rían W. Manville, Andrea Reyna-Neyra, Geoffrey W. Abbott, L. Mario Amzel, Nancy Carrasco. Allosteric regulation of mammalian Na /I− symporter activity by perchlorate. Nature Structural & Molecular Biology, 2020; DOI: 10.1038/s41594-020-0417-5
Posted by: AS