Paul M. Rady Department of Mechanical Engineering researchers have identified at least nine pesticide chemicals in the air around Boulder County homes that humans and their dogs have been exposed to.

The air quality study, led by PhD candidate and funded by a University of Colorado Boulder Outreach Award, tracked the chemicals that people and their dogs came into contact with in fall 2021. The 38 human-dog pairs that participated in the study had to wear wristbands and dog collar clips for a week that contained sampling tubes to measure the pesticides around them. 

“We used high-resolution mass spectrometry to analyze the samples," said Khalili. "The results showed that of the 15 compounds we were testing for, we detected nine of them. Three of them were detected in all the human and dog samples.”

The three compounds identified in all 76 samples were n-nitrosodiphenylamine, 4-nitroaniline and 4-chloroaniline. Each of those compounds can be found in pesticides and could pose various health risks including eye, skin and respiratory tract irritation. Very high and repeated exposures may damage the liver and kidneys, according to the EPA.

“These results could mean that the chemicals are in the air since the 38 people are not living together and have different lifestyles,” said Khalili. “If they are exposed to the same compound, it could say something about the community that we are living in.”

The study also detected DDD in one human and two dogs, and DDT in two humans and one dog, even though the United States has banned the use of both due to damage to wildlife. The that "after the use of DDT was discontinued in the United States, its concentration in the environment and animals has decreased, but because of its persistence, residues of concern from historical use still remain." 

“The fact that we even have detected DDD and DDT in any of the participants’ samples is a big deal,” said Khalili. “There is a 99% correlation between the dogs and their owners that were exposed to DDD and DDT, and yes, it is a small percentage out of the 38 pairings in the whole study. But we shouldn’t be exposed to those compounds at all.”

Khalili’s study focused on detecting the compounds rather than identifying where they are coming from. She noted the chemicals could have originated from pesticides, dog tick and flea medications, or industrial sources.

Khalili conducted this research after seeing several yellow flags on people’s yards around Boulder indicating that chemicals had recently been applied. She wanted to educate the community about the compounds that are in some of those pesticides and inspire people to live cleaner lifestyles.

Many of the participants have told Khalili that they are already being more conscious about using pesticides around their homes to protect themselves and their dogs. Khalili said she’s proud and excited to see community members taking this next step. Moving forward, she wants to promote even bigger changes.

“I would love to see the regulations around the compounds in these products that we use for gardening be revised,” said Khalili. “It wouldn’t happen overnight. We would need more studies to ensure that policymakers can rely on the results and make a change. I’d like to not see those yellow flags around anymore.”

Khalili partnered with the and to recruit participants and design the deployment of the study, since the city and organization are well connected with the community. Both collaborators also had a stake in the research, as they were interested in seeing what compounds are in their air.

“It was important to work with the City of Boulder because they could be empowered to make changes to regulations,” said Khalili. “With Healthy Baby Bright Futures, it was an educational opportunity. Our study can help teach mothers to not let their babies crawl on chemically treated grass, for example.”

Off

• Matthew An – Logistics manager
• Casey Cole – Test engineer
• Blake Fardulis – Project manager
• Kate Nichols – Manufacturing engineer
• Wesley Schumacher – Systems engineer
• Andrew Stiller – CAD engineer
• Aleksey Volkov – Finance manager

A team of seniors in the Department of Mechanical Engineering have designed and built a device that automates the disposal of scrap metal, making it safer and more efficient.

The students created the device as their Senior Design project sponsored by , a Littleton-based manufacturer of custom parts for customers in aerospace and industrial sectors. The Machining Chip Disposal System can lift and dump 600 lbs. of scrap material with the push of a button, cutting down the time it takes to dispose of the material from 30 minutes to five. That decreases the time spent per year on this cumbersome task from more than 1,000 hours to about 170 hours.

“Accu-Precision has 30 machines at their machine shop in Littleton, and they have a bin underneath each of them that gets filled up with scrap,” said the team’s project manager Blake Fardulis. “They have to dump those bins once a day, so the high-paid machinists have to stop what they are doing and haul the bins out to the dumpster. They either have to lift the bins themselves or use a forklift.”

The Machining Chip Disposal System automates this procedure. The device, made up of more than 110 different machine parts, can be remotely activated to save time and physical strain.

The Senior Design team said they are proud that their device will be used in industry. The disposal system is a functional piece of machinery, rather than a prototype or design idea.

“There is a lot of purpose to what we’re doing,” said Systems Engineer Wesley Schumacher. “It’s not just something we will send to the client that will be on the backburner for years. Accu-Precision will use it every day.”

The students said they were drawn to this project because of the purely mechanical work they would be tasked with. The students brainstormed and completed various CAD designs even before their application for Accu-Precision to be their sponsor was accepted.

“This is one of the most mechanical Senior Design projects, and the requirements that have been developed around that have flowed into the whole process,” said Andrew Stiller, the CAD engineer on the team. “It pushed us to question our ability to design devices and analyze them as well. It’s been a good process.”

Most of the team’s time creating the disposal system was spent in the Idea Forge Machine Shop for about 150 – 200 hours to fabricate 110 custom parts. The students said they were in the shop on day one of the spring 2022 semester to get started.

“The machining logistics could have been quite a nightmare, but we got it done on time,” said Manufacturing Engineer Kate Nichols. “We also had a welder through Accu-Precision, so that worked out very nicely. We sent what we needed over to them, and they helped us with that.”

The team said another rewarding aspect was the R&D process. The experience gave them a first-hand look at what a career in design and engineering consulting would be like.

“There are a lot of companies whose sole purpose is doing exactly what we did,” said Aleksey Volkov, the team’s finance manager. “The client comes to them with an idea and it’s the consultant’s job to solve that problem. One day it could be in aerospace; another day it could be in a different industry. Short-term ideation is really valuable.”

The students are now testing the Machining Chip Disposal System and finalizing the device’s appearance by routing wires properly, as well as making a smaller control box to for a sleeker look.

The team will be presenting the disposal system at the College of Engineering and Applied Science Engineering Projects Expo 2022 on April 22.

Explore all 2021-22 Senior Design Projects

Off