April 23, 2020 / John M. Reynolds

Too Many Pesticides, Not Enough Methods

Sponsored by ALS

NIOSH was developing air methods for one pesticide at a time in their own facility in Cincinnati, Ohio. But with all the new pesticides becoming registered, NIOSH realized it would take forever to develop these methods fast enough at a rate of one-at-a-time. NIOSH also realized that the methods were being developed using all kinds of air samplers. Dr. Eugene Kennedy of NIOSH decided that the agency needed a single universal sampler for all, or as many pesticides as possible, so that their IHs didn’t have to take a ”bucket” of different samplers into the field whenever they went on a job.

We at DataChem Laboratories, Inc., or UBTL at the time, were tasked to solve both problems: to come up with a universal air sampler, and to do as many pesticides at a time as possible. The assignment was given to me without any other restrictions.

I immediately began by breaking up the vast number of registered pesticides into compound classes—that is, those that could be analyzed together. I envisioned five groups: organo-phosphates (that could be determined by gas chromatography with flame photometric detector, or GC-FPD...this was in the days before gas chromatography-mass spectrometry, or GC-MS), organochlorines (those that could be analyzed by gas chromatography with electron capture detector, or GC-ECD), organonitrogens (those that could be determined by gas chromatography with nitrogen phosphorous detector, or GC-NPD), herbicide acids (to be determined by high performance liquid chromatography-ultraviolet light, or HPLC-UV), and dithiocarbamates (for example, the fungicide maneb) by a yet undetermined method.

Organophosphate pesticides method development came first on an agreed-to list of pesticides, ultimately becoming air method NIOSH 5600 (PDF). However, the real turning point came when we developed air method NIOSH 5605, which consolidated all pesticides analyses (methods) by using the GC-MS analytical technique.

As far as a universal sampler was concerned, I went to the University of Utah library and searched through journals to see what was known about the subject. There, I discovered enough information to suggest both a filter and a backup sorbent tube were needed. Then I received a flyer in the mail advertising OSHA Versatile Samplers. They appeared to be ideal because both a filter and sorbent were incorporated into the same glass tube. Not long after that, we discovered that SKC made them also.

We asked SKC to send us some of the components of the sampler for testing. At this time, the sampler had XAD-2and a glass fiber filter (GFF). Serendipitously, we got a heads-up by a chemist at Bayer Corporation to use quartz fiber filters (QFF) instead of glass, so we persuaded SKC to cut and send some of those too. With the testing that we did, we found that QFF were better for the more polar pesticides. Out of the method development for NIOSH 5600 arose the SKC 226-58, which had the QFF instead of the GFF. We have used this media since for all other NIOSH pesticide method development processes. At this time, this media is essentially the NIOSH universal pesticide sampler, even though it is still called the OSHA Versatile Sampler, but with a QFF suffix, or simply SKC 226-58.

John M. Reynolds

John M. Reynolds is a senior research scientist at ALS Environmental in Salt Lake City, Utah. Throughout his tenure, which began in 1975, he has been instrumental in developing equipment and new procedures to perform analyses for complex industrial hygiene analytical chemistry methods for the industry. In addition, John is a published author with several publications in the Journal of Agricultural and Food Chemistry, Applied Occupational and Environmental Hygiene, and many others.


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