Quirks in regulations create need for science-based pesticide limits, USP says

In a session at the 17th Annual Conference on the Science of Botanicals taking place in Oxford MS this week, Nandakumara Sarma PhD director of dietary supplements at USP, said the way pesticide regulations are written in the United States, many botanical ingredients are in the untenable position of being subject to import seizure if even trace amounts of certain pesticides can be detected in the lot.  In other words, for some pesticides when found in certain botanical materials meant for dietary supplements, there is a zero tolerance policy, even if those same pesticides are allowed at higher (but still low) levels on lots of material meant to be consumed as food.

Intentional vs unintentional

Sarma said the issue came about this way: Pesticide regulations in the U.S. have been promulgated by the Environmental Protection Agency and pertain to known risks from pesticides applied to food crops. The verb is important in that sentence, as these regulations only cover intentional applications, and were written on a crop-by-crop basis. But Sarma said some of the underlying principles behind the legislation no longer hold true. The underlying assumption was that if a detectable amount of a pesticide showed up on a crop, it got there because the farmer put it there. If there is no specified level for that pesticide in a given crop, the tolerance level automatically reverts to zero.

 But pesticides have been in wide scale use around the globe for seventy years or so now, and many of these chemicals, especially the older, legacy pesticides, were engineered to be persistent in the environment. Pesticide residues have been detected in alpine snow fields and Antarctic ice. As a result, Sarma said, finding places in the world where crops can be grown or botanicals can be wild harvested without at least trace amounts of unwanted pesticides showing up is becoming nigh on impossible.  This issue is coupled with the fact that analytical methods have advanced, and ever lower detection limits are possible. This is of particular concern for wildcrafted items, which make up a large proportion of the trade in botanical dietary supplement ingredients. The global wildcrafted botanical ingredient supply chain we know today was really a tiny niche market activity when the principles underlying the pesticide rules were put into place, Sarma said.

“In wild harvest, no EPA pesticide levels were ever established for these crops,”​ Sarma said. 

Need for science-based limits

Sarma said the intended use of the item also changes the allowable pesticide limits, giving rise to situations that make no objective sense. For example, the pesticide trycylazole is allowed at 3 ppm on rice. But as there is no level established for this pesticide in a botanical dietary ingredient that would go into a supplement, it may not be present at any level in that material, even though a consumer could be expected to consume hundreds of times more of the rice by volume in a day.

The intended use of the item—or, put another way, the sales category of the finished product—can affect the pesticide tolerances on the same ingredient, too, Sarma said.  For example, one tolerance level applies to psyllium seed husk when used in an OTC bulking laxative, and another when it is sold as a dietary ingredient for dietary supplement use, even if the dosage is the same in both cases.  Sarma showed attendees two slides listing more than 30 common botanical dietary ingredients.  Of these only five had EPA pesticide limits associated with them.

Sarma said USP is engaging in roundtable discussion with EPA, FDA, USDA’s Organic Standards Board, Health Canada and others to address the issue.  The goal is not to give industry an “out,” but rather to rationalize and harmonize the regulations along risk-based and science-backed lines.

“The supply chain is really global. We live in a contaminated world, and while we want the pesticide levels to be as low as possible, we are trying to address the gaps in the regulations,” ​Sarma said.

In addition to the Oxford meeting, Sarma recently presented the issue at a meeting of the Toxicology Forum in Washington, DC and will present it again next month at a workshop in San Francisco put on by the California Specialty Crops Council. To read USP’s original stimulus article on the subject, click here​.

The  Oxford conference, put on by the National Center for Natural Products Research at the University of Mississippi, began on Monday and wraps up today.  For more information on the conference, click here​.