St. John-Mittelhauser & Associates (SMA) is responsible for implementing July 6, 2017, Soil Management Plan (SMP) that was approved by IDEM. Excavation work for the installation of new storm sewers on the property began August 14th. The SMP details the protocols that are to be utilized related to the excavation and handling of excavated soil at the KPEP site. The SMP also contains a Health & Safety Plan (HASP) that provides details on how excavated soil is monitored and the personal protective equipment (PPE) that is utilized to protect workers from constituents of concern (COCs) that may be present in Site soils. A representative of SMA is present on the Site every working day to perform soil monitoring, oversee the use of PPE, ensure that exposed soil from excavations and borrow soil are wetted regularly (dust control), assist the contractor in utilizing the on-site remedial groundwater water treatment building (GWTB) to process water from trench dewatering (a combination of rainwater and shallow groundwater) and performing daily air monitoring at the Site for dust and lead.
The COCs for the Site include antimony, arsenic, barium, beryllium, cadmium, chromium, copper, cyanide, lead, mercury, vanadium, nickel, zinc, ammonia, chloride, fluoride, sulfate and cyanide. IDEM noted in their Comfort Letter of June 30, 2015, that the principal COCs driving the cleanup are lead zinc and ammonia. With the exception of ammonia, the COCs are metals that have a strong tendency to tightly adhere to soil particles. With that characteristic, any lead or zinc that is present in excavated soil can only mobilize via soil dust. Compared to zinc lead is the more toxic metal. Filter masks are used by excavation workers to prohibit any possible inhalation of lead in dust particles via mouth or nose. Because the vast majority of the Site is a concrete slab, the freshly excavated soil is moist thus there is little chance that dust is produced when soils are initially excavated. From that point on all excavated soil is kept moist by water trucks to eliminate the production of dust. Excavation workers are also wearing Tyvek garments for the purpose of utilizing clothing that is thrown away at the end of the day and to eliminate the possibility of a worker wearing a garment home that is smeared with soil that might contain traces of lead. Workers are only wearing Tyvek during sub-surface excavation.
In order to determine if lead contained in dust is being produced from construction activities at the Site, SMA has located 4 air sampling stations on the perimeter of the Site as shown in Figure 1. Air samples are collected with a battery-powered vacuum air pump which accumulates any dust on a filter contained in a plastic cassette. The pump and cassette are mounted on a post at a height of 5 feet above ground surface. Each pump operates for about 8 hours during every working day when the soil is handled at the Site. Any rain that occurs during the 8 hour sampling period negates the analysis of the samples that are collected. Sample turnaround time (TAT) is 1 week, available results are provided in Table 1. Sample results are well below the OSHA criteria, in most instances by two orders of magnitude (100X).
The presence of ammonia is routinely monitored in the excavation trenches with a COC-specific meter. Because ammonia can volatilize, any high levels of ammonia in soil would quickly dilute and dissipate in the open air. This is would be analogous to farmers spraying or injecting anhydrous ammonia during planting. Volatile Organic Chemicals (VOCs) are also monitored during soil excavation with a photoionization detector (PID). VOCs are not COCs for the project; however, this type of monitoring is typical for most environmental investigation and remediation. Thus far no detectable levels of ammonia or VOCs have been identified in any soil that been excavated or in the trenches where workers are setting pipe.
Figure 1 also shows the progress of storm sewer installation in the first three weeks of the project. Beginning on August 25 clean soil was brought onto the Site from a nearby borrow pit and placed onto Lot 5, the southwestern portion of the Site where it will be compacted in lifts to raise the lot to the proposed design elevation (the engineered soil cap).
Mike McCann of IDEM VRP performed an unannounced inspection of the Site on August 17, 2017. He noted in his attached report “that site activities were being conducted according to the agreed work plan and the workers, as well as the public, were being protected”.