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Radiation and Cadmium Contamination at the Beta Scanner Factory
Fig 1. Collecting a soil sample after the first excavation.
There was a factory in Nassau County where they made hand held devices called Beta Scanners. These instruments were used to measure the thickness of metal plating (like chrome or cadmium plating)
The scanners emitted mild radioactivity that would bounce off the plating and the metal underneath and somehow the scanners would calculate the thickness of the metal plating (a beta particle is emitted from radioactive material when a neutron is transformed into a proton and an electron. The electron that is emitted is called a beta particle. Beta rays are streams of beta particles)
The factory also had a small plating line so that they could produce samples of plated metals so they could test the scanners. ( a plating line is a series of tanks with plating solutions and rinse waters. The parts are lowered in succession into the different tanks, and at the end of the line, the plating is completed)
The problem at this factory was that they improperly disposed of the plating solutions and/or rinsewaters by pouring it into a pipe that led to a drum that was buried outside the building, very close to the outside wall. The drum had holes in it so the liquids would drain into the sandy soil.
The soil under the drum was contaminated and the worst contamination was from cadmium.
The reason that we found out about the contamination was that the company that owned the factory decided to move the scanner manufacturing to another factory building and they put the scanner factory up for sale.
Nowadays, when commercial buildings are put up for sale, the potential buyers and the banks that lend the money usually ask for an environmental investigation to find out if there is any pollution problems at the site. This investigation is called a Phase 1 investigation.
When the Phase 1 was done on the Scanner building property, they found the soil contamination from the plating line.
The owners wanted to clean up the contamination so they could sell the property. They came to the state DEC and said if we clean up the contamination will the state watch over the work and write a letter to the buyer when the work is completed? We said yes- but you have to do a good job.
I was the project manager for this job. The first work was the drilling of soil borings through the contaminated soil. The collected soil samples at different depths so they could find out how deep the soil was contaminated. The soil samples were sent to a lab and tested for cadmium and other contaminants.
After the testing was completed, we found out that the contamination went down about 25 feet and it was right next to the building.
And they said "We cant dig up the contaminated soil- the building will fall down!"
And we said- "If you dont clean up the contamination, we cant write a letter (and you wont be able to sell the property!)"
They got some estimates from different contractors on different ways to remove the contaminated soil. One proposal was to remove a large section of the wall of the building, dig up the soil, put in clean soil, and then rebuild the building.
The second proposal, (which they chose), was to install large steel I beams up close to the building. (An I beam is called that because the cross section of the beam looks like the capitol letter "I".) The I beams were about 50feet long and they were pounded into the ground with a pile driver. (A pile driver is a large crane with a huge sliding weight. The weight is lifted up and down onto the I beam, over and over, pounding it into the ground.)
Fig 2. The tall machine in the background is the pile driver crane
Four I beams were installed up close, right next to the building. Four more I beams were installed outside the area of contamination.
Fig 3. The 4 steel beams were installed close to the building
The workmen dug out by hand the soil by the I beams next to the building. They dug down deep enough to get to the bottom of the foundation. They welded steel brackets to the I beam. The purpose of the brackets was to hold up the building when the soil was removed.
Fig 4. Steel brackets were welded to the I beams under the footings of the building.
Also, I beams were to be installed away from the wall, outside of the contamination area.
Then the digging started with a bucket excavator.
Fig. 5 We see the bucket going into the excavation.
Fig 6. the bucket is in the excavation
To keep the sandy soil from caving in, wood planks were to be installed behind the I beams as the soil was removed by the crane. As the hole got deeper, more wood planks were added.
Fig 7. Digging and installing the wooden boards
Fig 8- Installing wood.
Fig 9. Installing a horizontal steel beam for strength.
After about 2 days of digging, the hole was about 25 feet deep. The hole was lined with the wood planks, which were held in place with the I beams.
Fig 10. This shows how deep the excavation was. Note that in the upper right of the photo the concrete footing of the building can be seen.
Then, soil samples were collected and sent to a lab to be tested
for cadmium- to find out if all of the contaminated soil had been removed- it had. Then
the hole was filled up with clean soil (the new soil had to be tested to make sure it
Fig 11. Filling the excavation
Fig 12. The excavation is almost all filled in. Note- in the left foreground there is a PID meter which is used to check if the new soil is clean. The PID meter can detect contamination of volatile chemicals
Fig 13. The man on the left is pushing a machine that compacts the soil. If the new soil was not compacted, it would later sink as much as 30%.
As the new soil was put in the hole, the planks were removed, one by one. When the hole was completely filled in, the pile driver pulled out the I beams.
Fig 14. The contaminated soil that was removed, before it was trucked away for proper disposal. 618 tons of contaminated soil was excavated and disposed of properly.
We wrote a completion letter, the company sold the property.
After that, we had a few jobs with a similar situation of soil contamination up close next to buildings. The people would say, " I cant dig up the contaminated soil- its right up next to the building and the building will fall down"
And I would say, "Yes you can!" and show them the pictures.
Consider the trees
that allow the birds to perch and fly away
Last Updated March 13, 2011