Site Characterization and Clean Up

Sargeant Avenue Shortly after the discovery of asbestos, the City's asbestos abatement contractor began work at Sargeant Avenue to identify the nature and extent of asbestos contamination in soils in the detention pond area.

Between April 3 and April 9, 2003, a total of 124 subsurface test borings were made at approximate 25-foot intervals throughout the excavated area. Test borings were made to a depth of 2-½ to 3 ft. to determine the possible presence of asbestos wastes at shallow soil depths. Of the total number of borings made, visual inspection showed that suspect asbestos wastes, in the form of plate or bag house wastes, were present in some 33 test borings.

During this characterization, three samples were collected and submitted to a laboratory for analysis by Phase Contrast Microscopy (PCM). The three samples that were analyzed consisted of one sample each of bag house waste, plate waste and board type material.

The three samples analyzed were positive and shown to contain 20% chrysotile asbestos. It is important to note that normally the results of asbestos analyses are reported on a "weight" basis; however, the exact method used to analyze the three samples was not contained in the documents reviewed for this health consultation.

At the same time, air sampling was also conducted in the Sargeant Avenue area to determine whether asbestos, in the form of airborne fibers, was being released from the excavated portion of the site. A total of 14 air samples were collected while the soil characterization work was underway.

All of the air samples collected showed asbestos at concentrations of less than 0.002 fibers per cubic centimeter (fibers/cc), which is significantly lower than the ATSDR community action level of 0.01 fibers/cc, indicating that the airborne release of asbestos from the site was not a public health concern.

In response to the discovery of a new asbestos waste site in a heavily populated residential neighborhood, the City developed and submitted a clean up plan to DES for the Sargeant Avenue site. Later in April, following the initial discovery of asbestos, the remaining contaminated soils were transported to the Four Hills Landfill for disposal and the detention pond excavated area was covered in accordance with appropriate federal and state environmental regulations.