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HomeMy WebLinkAboutRE_ NHC SLO 2600 Broad Street Closure Report1 Christian, Kevin From:Bliss, Matheson Sent:Tuesday, July 13, 2021 8:49 AM To:Clarence Reynolds; Daniel Ringstmeyer Cc:William Sarten; John Hochleutner; Maggio, Rodger Subject:RE: NHC SLO 2600 Broad Street Closure Report Hi Clarence, Thank you for the response. Dan, Could you please incorporate this into the closure report and add some additional information? I still only see one figure with 6 sample locations noted. Please add figures for the Sump and Fire Trench (Originally, samples were taken from the West Wall of the Sump Trench and at the bottom of the South End of the trench (OEC Lab ID#s 2101841-07,08). After data showed further excavation was required and carried out, a sample was taken from the Sump Trench West side (OEC Lab ID# 2103032-01) in the middle of its length because that is where most of the brick was. A sample was also taken from the bottom center of the trench (OEC Lab ID# 21020302-03). This Process was repeated for the Fire Trench with the inclusion of a sample on the East side of the trench were the material seemed to be consistent along the length of both trenches.) Add a figure for the concrete excavation (Five samples were taken from the floor of the excavation. See OEC Lab ID#s 2102742-01 through -05. The sample locations are as follows: NW Corner @ 8’, NE Corner @8’, SW Corner @ 8’, SE Corner @ 8’ and the center of the excavation @ 8’….. Once it was believed that all contaminated material was removed two verification samples were taken from the excavation floor approximately 4’ East and West from the center where the highest amount of petroleum had been present). Add a data table for the tank slurry and coating (The tank had been filled with a concrete slurry. There was also a thin layer of what appeared to be petroleum on the outside of the tank. Both the coating and slurry were sampled. See OEC Lab ID#s 2101909-01 and 2102464-01).Clarify in the data tables which area the samples were collected from (e.g. the bins in the data tables on pg 24, 26, and 27 were excavated from which area of the site; the soil sample “N TK Wall” on pg 28 is referring to which excavation?). Rectify information on the diesel tank soil pile. It was stated only three sides of the soil pile were sampled; however, per table on pg 29, four soil pile samples were collected (A sample was not taken from the East side as it was too close to the mouth of the excavation and unsafe… however there is a “Soil Pile E” sample.) Please confirm site location on all tables. Further clarify contaminants of concern if there was no Phase I performed for the site. In the diesel tank excavation, if groundwater was observed infiltrating the excavation, was a sample collected and what are the results? Thank you, Matheson Bliss Hazardous Materials Coordinator Fire Department Fire Prevention E mbliss@slocity.org T 805.781.7383 C 805.540.4413 slocity.org Stay connected with the City by signing up for e-notifications  2 From: Clarence Reynolds <c.reynolds@ppcinc.biz>   Sent: Friday, June 18, 2021 2:56 PM  To: Bliss, Matheson <mbliss@slocity.org>  Cc: William Sarten <w.sarten@ppcinc.biz>; John Hochleutner <john@ppcinc.biz>  Subject: NHC SLO 2600 Broad Street Closure Report  This message is from an External Source. Use caution when deciding to open attachments, click links, or respond. Hi Mattie, I hope this gives you a better idea of how the project proceeded. Unfortunately, the Diesel Tank Excavation and Trench area have been backfilled so no pictures are available. Please let me know if you need more detail. 1. Describe the two distinct excavations (diesel tank and concrete structure), the trenches (noted on 4/6 data table), and soil piles and bins that are also noted on the data tables. Add additional figures detailing these areas and specific sampling locations. Diesel Tank Excavation: OEC Lab ID# 2101841-01 through 04 – Tank Wall Samples were taken at depth of 4’ in the center of each wall. 2101841-05 & 06 Tank Bottom Samples were taken at a depth of 8’ at the inlet and outlet ends of the tank. These samples were located at the bottom center of the East and West ends of the excavation approximately 1’ from the East and West walls respectively. The sample locations can be seen on page 9 of the closure report. The soil excavated from the diesel tank removal generated a pile approximately 5’ in height, 8’ in length and 4’ in width. Composite samples were taken from the North, South and West sides of the pile. This was done by taking three equal amounts of material from halfway up each side of the pile at intervals of about 1’5” and a depth of about 6”. These aliquots were mixed into three composite samples representing the three sides of the pile. A sample was not taken from the East side as it was too close to the mouth of the excavation and unsafe. Trenches: A trench was dug approximately 3’ deep to accommodate a water line. A pile of soil and brick was generated. It was approximately 3’ in height, 6’ in length and 4’ in width. A composite sample was taken from the pile by taking six equal amounts of material from half way up the pile (1.5’) at 2’ intervals and a depth of approximately 6”. These aliquots were combined into a single sample. As the excavation continued, the trench was segregated into two sections for sampling. This was done because half the length of the excavated material was composed of soil and the other length contained brick as well as soil. The length containing only soil was dubbed “Fire Trench” and the other “Sump Trench”. Originally, samples were taken from the West Wall of the Sump Trench and at the bottom of the South End of the trench (OEC Lab ID#s 2101841-07,08). After data showed further excavation was required and carried out, a sample was taken from the Sump Trench West side (OEC Lab ID# 2103032-01) in the middle of its length because that is where most of the brick was. A sample was also taken from the bottom center of the trench (OEC Lab ID# 21020302-03). This Process was 3 repeated for the Fire Trench with the inclusion of a sample on the East side of the trench were the material seemed to be consistent along the length of both trenches. Concrete Excavation: During the excavation of the trench, the outline of a brick structure was discovered containing lose bricks and soil. As this material was removed, a concrete slab was uncovered. Brick and soil from this excavation was placed into several twenty cubic yard bins. This material was sampled by taking three samples from each bin. Material was taken from the center of each bin moving left to right at a distance of 3’ apart for each sample (A, B, C). See OEC Lab ID#s 210508-01 to -15. The concrete slab was removed and it was discovered that there was hydrocarbon impacted soil underneath it, most likely from the removed fuel tank. Five samples were taken from the floor of the excavation. See OEC Lab ID#s 2102742-01 through -05. The sample locations are as follows: NW Corner @ 8’, NE Corner @8’, SW Corner @ 8’, SE Corner @ 8’ and the center of the excavation @ 8’. The data for these samples showed the presence of weathered hydrocarbon and that more material needed to be removed. Two twenty cubic yard bins of material were excavated and sampled in the same manner as the other bins. See OEC Lab ID#s 2103212-03 through -08. Once it was believed that all contaminated material was removed two verification samples were taken from the excavation floor approximately 4’ East and West from the center where the highest amount of petroleum had been present. Results from these samples showed that the petroleum had been removed to an acceptable level. 2. Reasoning for contaminants of concern (e.g. why weren’t SVOCs, PAHs, etc. included in testing). These compounds were not considered necessary due to the nature of the site. There was no indication that they would be present for any reason considering the location and types of businesses in the area. 3. History of the site, possible uses of the diesel tank and concrete pit, reason for high lead. Any information on diesel tank closed in place. To the best of our knowledge, there is no available phase one assessment for this site. Apparently somewhere close to the site there was a brick factory. The tank was likely used either for fueling or for waste. The tank had been filled with a concrete slurry. There was also a thin layer of what appeared to be petroleum on the outside of the tank. Both the coating and slurry were sampled. See OEC Lab ID#s 2101909-01 and 2102464-01. The tank was then disposed of at the McKittrick Land Fill. The bricks are possibly left over from a demolished structure, of what kind it is not clear. The concrete may have been a cap for the fuel contamination underneath it. Although the chromatographs for the TPH data show a weathered diesel pattern, it is possible that gasoline range organics may have been present and have degraded. Due to the presumed age of the site, this may have been leaded gasoline explaining the presence of lead. 4. Depth to groundwater in the area. Approximately 15’ to the NE of the Diesel Tank Excavation between the former Quik Mart and the building that will be the NHC SLO, ground water was discovered at a depth of 2’. In the tank excavation, ground water was discovered at a depth of 5’. No ground water intruded into the second excavation were the bricks and concrete slab were found. 4 Best Regards, Clarence Reynolds Compliance – CST P.O. Box 2646 | Orcutt, CA 93457 (805) 925-1947 EXT 352 | Fax: (805) 925-0884 | Cell: (805) 868-9081 Website: www.ppcinc.biz   Attention: During the COVID‐19 pandemic please anticipate a delay in response time to our emails. Safety being our  number one priority requires us to take social distancing measures. We appreciate your patience and understanding  during this time and will respond as soon as possible.