Marty Williams, Co-Founder and Principal Water Resources Engineer

I am excited to announce that the following articles coauthored by WEI members have just been published in Integrated Environmental Assessment and Management as open access:

Environmental fate of monosodium methanearsonate (MSMA)—Part 1: Conceptual model

Environmental fate of monosodium methanearsonate (MSMA)—Part 2: Modeling sequestration and transformation 

One of my favorite quotes is from Max Planck, the German physicist who won the Nobel Prize in Physics in 1918 by his discovery of energy quanta.

“When you change the way you look at things, the things you look at change.”

MSMA is a selective contact herbicide that has been proven to provide effective control of a wide range of problematic weeds in cotton, turf, and rights-of-way. It has also proven to be among the most interesting and challenging chemicals I have worked on in my career given its behavior in the environment.

The complexities of MSMA and the challenges in analytical procedures have led scientists to false conclusions in the behavior of the chemical under the conditions of where it is used. Part 1 discusses the complex behavior of the chemical and a number of the challenges in conducting laboratory and field studies and interpreting the results of the studies that have been conducted. Part 2 presents a creative way of applying PRZM5, an regulatory-approved linear and equilibrium model to simulate the kinetics of MSMA behavior in a geo-referenced exposure assessment.

We hope that these articles will encourage other scientists to “change the way they look at things” to examine and conduct studies from a lens of relevance:

• Do the test systems represent conditions in which a chemical will encounter?
• From a lens of significance, are the most important processes governing a chemical’s behavior being represented appropriately in model predictions?

Please click on the links to see the author list. It has been a pleasure for me to work with such a high caliber, multi-disciplinary team, who collectively allowed us to solve the “Rubik’s Cube” in understanding and predicting the environmental fate of MSMA.

Figure 1. Conceptual model of monosodium methanearsonate (MSMA) transformation and sequestration processes. Gray = conceptual model (all processes) and Dark = reactions modeled with Pesticide Root Zone Model, version 5. The arrows depict the direction of the sorption and transformation processes. The rate constant of each process is represented by the variable “k.” DMA, dimethylarsinic acid; iAs, inorganic arsenic; MMA, monomethylarsonic acid