The Site consists of an approximately 25,000 square foot (0.67 acre) parcel, identified as Block 4284, Lot 5 and is zoned as a residential district by NYC. The Site is known as 2040 White Plains Road and is located on the east side of White Plains Road between Bronxdale and Brady Avenues. There used to be one commercial building on the site, approximately 1512 square feet in size which had one floor and no basement. The building was constructed in 1954 and has been used as a service/gasoline station since its construction. The building was demolished during the site development. The property is located within a residential area which is comprised of residential apartments and commercial buildings, such as restaurants, supermarkets and gas stations. To the north of the property, there is a one story strip mall which contains a restaurant, martial arts studio and parking garage. There is a supermarket and bingo hall to the south. A Mobil gas station is located across White Plains Road to the west. A six story residential building is to the east. Prior use as a service/gasoline station has impacted soil and groundwater with releases of gasoline and waste oil. Investigation and remediation activities have been conducted onsite, which included the removal of USTs, removal of impacted soil, and injection of Chemical Oxidant (sodium persulfate). The preventive measures included installation of the vapor barrier and the Sub-Slab Depressurization System for the new building. The site is developed with a slab-on-grade multi-story building, where the first and upper floors are used for commercial and residential purposes respectively. The remedial construction was completed in February 2007. Currently, the store located on the first floor is opened for business. An Environmental Easement was executed by the Department and Volunteer on this property and filed in the Bronx County Clerk’s office on 12/27/2007. A Site Management Plan was approved by DEC on 12/21/2007 and will be reviewed for compliance in September 2008. The Final Engineering Report was approved on 12/28/2007 and a Certificate of Completion was issued on 12/28/2007. Groundwater contamination has migrated off site and is being investigated by the Responsible Party (Shell) under the Spills Cleanup Program (Spill No. 9802162).
Site Environmental Assessment
The property had been in continual service as a gasoline service station for approximately 50 years. The results of the investigations conducted at the site during 1998 (Limited Phase II Site Investigation), July 2004 (Subsurface Investigation), December 2004 (Phase I Environmental Site Assessment), January 2005 and August 2005 (Remedial Investigation), revealed that soil and groundwater beneath the site were impacted by petroleum hydrocarbons, gasoline and waste oil. There were USTs, dispensers, fuel line pipings and hydraulic lifts associated with the former gas station. The results of the soil sampling indicate that the primary source of residual VOC contamination is in the former waste oil tank area at north of the former station building. The area of highest VOC contamination in groundwater exists beneath the former station building. Concentrations of VOCs exceed drinking water quality standards across the site and contamination were also found in soil vapor samples. Contaminants of concern at the site are as follows: Soil - VOCs, SVOCs, and some metals were identified in the soil at concentrations exceeding the TAGM 4046 Recommended Soil Cleanup Objectives (RSCOs). One waste oil tank was located north of the former station building. Three gasoline tanks were located south of the former station building. Dispenser islands were located west of the former station building. Groundwater - The highest VOC concentrations detected in groundwater beneath the former station building range from 119 ppm to 146 ppm of total VOCs. The concentrations of VOCs exceed drinking water quality standards across the site. Soil Vapor - Total VOC concentrations detected in first round of soil vapor samples were fairly consistent throughout the site, ranging from 1,354 ug/m3 to 3,439 ug/m3. The second round soil vapor samples collected on July 2006 revealed BTEX concentrations ranging from 131 ug/m3 to 15,852 ug/m3 and total VOC concentrations ranging from 651 ug/m3 to 94,040 ug/m3. The highest VOC concentrations in soil vapor were detected in the vicinity of former waste oil tank area. NYSDOH has determined that, prior to remediation, the Site’s condition posed a significant threat to human health or the environment. The remedial actions implemented at the Site under the IRM have been effective in both reducing the potential for vapor off-gassing from groundwater and preventing exposure through vapor intrusion into the new building a the site. The Site no longer posses a significant threat to human health or the environment. The remedy implemented at the site included the following: * The removal of USTs and impacted soil which have been implemented under the first IRM’s. * The hotspot Chemical Oxidant injections were implemented under the second IRM. * Continued spot ChemOx injection has been implemented under the final RWP following completion of the IRMs. All aforementioned remedial measures have been completed, although additional ChemOx injection may be warranted contingent on receipt and review of additional groundwater monitoring data. Preventive measures, which include the installation of a 30-mil vapor barrier beneath building foundation and the installation of Sub-Slab Depressurization System (SSDS), have been implemented. The operation of SSDS will be continued unless otherwise directed by NYSDOH and NYSDEC. The post remediation groundwater sampling program, and the operation, inspection and maintenance of the SSDS under Site Management Plan have begun. Track 1 cleanup status is contingent upon achieving the remedial goal for groundwater and soil vapor within five years of the date of issuance of the COC. The Department does not foresee any unacceptable impacts to the environment from the Site provided the Site Management Plan (SMP) continues to be implemented.
Site Health Assessment
Exposures via drinking water are not expected because this mixed industrial/residential neighborhood is served by public water. Additionally, exposure to on-site soil is not expected because the site is covered with asphalt and a building. To prevent potential soil vapor intrusion in the new building an active sub-slab depressurization system was installed. NYSDOH and NYSDEC is evaluating the need for additional investigations to determine the potential for soil vapor intrusion into structures near the site.
Contaminants of Concern