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Hazardous Waste Cleanup: BASF (Formerly: Cognsis Corporation) in Ambler, Pennsylvania

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Cleanup Status

EPA had reviewed the existing groundwater investigation and has determined that the groundwater plume does not extend off-site.  Monitoring on-site will continue.  An environmental indicator of “Yes” for groundwater contamination was determined on November 13, 2013. An environmental indicator of "Yes" for human exposure was determined on  September 23, 2016.

An environmental covenant was recorded in Montgomery County July 11, 2011 and was updated July 21, 2016.  This covenant requires BASF or any future owner of the property to restrict land and groundwater use activities to those compatible with non-residential, land-use categories.  In addition, the covenant requires inspection, maintenance and record-keeping to assure the integrity of the engineered cap that overlies Building 14 Area.   All institutional controls applicable to the Sitewide Soils are now contained in the July 21, 2016 Environmental Covenant.

Cleanup Background

Low-flow extraction and ex-situ ozone-peroxide treatment of contaminants removed much of the most highly contaminated parts of the plume between 2007 and 2011.  Additional treatment, hydraulic and pneumatic fracturing in conjunction with in-situ injections of a biodegradation product in 2010 and 2013 was evaluated periodically to determine if modifications were needed to the system.   The 2013 - 2018 monitoring showed a considerable reduction in the size of plume and concentration of the contaminants. Perimeter monitoring shows that the plume is contained within the property boundary and does not extend off-site. 

BASF Corporation (BASF), Cognis and previous owners directed several environmental investigations and/or remedial activities at the Facility between 1980 and present.  Several of these actions were performed under oversight by Pennsylvania’s Land Recycling Program (Act 2) and/or EPA.  The data gathered during these investigations were compared to PADEP’s residential, non-residential, site-specific, and used-aquifer Statewide Health Standards (SHS), which are comparable to EPA’s Regional Screening Levels in addition to site specific standards derived from risk assessments at specific areas.

The environmental investigations at the site have focused on soils, groundwater and potential for vapor intrusion.  Sitewide investigations are described below.  Due to specific concerns with Buildings 14 and 23, the Residential Parcel, and the Ballfields, investigations and remedial actions taken at each are described separately. 

Sitewide Soils

A number of soil investigations and remedial activities have taken place on the site.  Investigations in 2003/2004 focused on the most likely industrial-impacted areas of the site.  The 2006 investigation was a more comprehensive evaluation of the entire site. In total, the 2003/2004 and 2006 investigations included 286 samples collected from 167 locations and included analysis for metals, Volatile Organic Compounds, (VOCs), semi volatile organic compounds (SVOCs), pesticides, herbicides, polychlorinated biphenyls (PCBs), cyanide and dioxin.  Thirty-one (31) samples identified compounds at levels above the applicable non-residential Statewide Health Standards (SHS) under Act 2.  These 31 detections for ethylbenzene, xylenes and arsenic, were found at 13 sampling points, generally near Former Tank 2. 

Excavations at the areas that exceeded cleanup levels removed 265 cu yd of contaminated soils.  Post-excavation confirmation sampling confirmed cleanup levels were met for ethylbenzene, xylenes and arsenic.

In sitewide soil investigations, ethylbenzene and xylene were the only constituents found to have the potential for volatilization to air.  Ethylbenzene and xylene levels slightly exceed the criteria for potential volatilization at two isolated areas which are more than 100 ft from buildings and were detected more than 5 ft below ground surface.  Soil does not pose a vapor intrusion risk to buildings.

The 2008 sitewide soils investigation and Final Report received PADEP Act 2 approval on June 18, 2015.

Building 14 Area

As a special project, BASF directed several investigation and remediation tasks associated with soil around Building 14 and railroad (RR) siding that formerly existed along the southwestern side of Building 14. The majority of the actions related to the RR siding occurred between 1983 and 1994, and involved dioxin (2,3,7,8-TCDD) and arsenic in soil. 

Approximately 380 cu yd of dioxin-contaminated soil where excavated from the RR siding area under a 1986 Administrative Consent Order (ACO) issued by EPA.  The excavation ranged between 1 and 3-feet deep over an area of approximately 5,500 sq ft.  Dioxin cleanup tasks were successfully performed to meet an EPA mandated cleanup criteria of 0.246 mg/kg.  Arsenic cleanup tasks were successfully performed to meet an EPA and PADEP-approved, risk-based screening level of 3,066 mg/kg.  EPA approved the clean-up by letter on January 22, 1999.

2,4,6-trichlorophenol, 2,4-dicholorphenol (2,4-DCP), 2,4-dichlorophenoxy acetic acid, 2,4,5-trichlorophenoxy acetic acid, naphthalene, dioxin and arsenic were found at to exist at levels above the SHS in the Building 14 Area.  EPA/PADEP agreed that attainment of SHS was not feasible and required additional efforts to remediate the Area through engineering controls and risk assessment.

Remedial action consisted of the installation of 4-inch thick asphalt cap on top of 1-ft deep fill along the entire south-southwestern side of the Building 14.  Building 14 is roofed and constructed of concrete, brick, and steel.  With the addition of the asphalt cap, the Building 14 area is completely surrounded by asphalt and concrete, which serves as an engineering control (cap) for the area.

A risk assessment was developed using landscape and outdoor maintenance workers as the anticipated receptors.  The assessment indicates that the remaining concentrations of constituents at the Building 14 Area do not pose a risk to receptors.

Volatile organic compounds were not found in the Building 14 Area; therefore, potential vapor intrusion is not a pathway of concern for this area.

The 2008 Final Report which included engineering and institutional controls and a Post-Remediation Care Plan for Building 14 Area received PADEP Act 2 approval on June 18, 2015.

Building 23 Area

Building 23 was an operational research and development laboratory that could not be accessed for purposes of an environmental investigation at the time of site-wide assessment activities in 2006.  Building activities ceased in 2012, and a soils investigation was initiated.  This was followed by an indoor air investigation also in 2012.  A total of 11 soil samples were collected from 10 soil locations.  Levels of arsenic exceeded non-residential standards at three (3) soil locations and 1,2-Dichloroethane (1,2-DCA) and 2,4-DCP exceeded non-residential standards at one (1) soil location. 

Risk assessment calculations similar to those completed for the Building 14 Area were used to determine that the remaining concentrations of constituents in soils at the Building 23 Area do not pose a risk to receptors, provided the building slab remains in place.  Using the current engineering controls associated with the Building 23 concrete slab, all exposure pathways were found to be incomplete, requiring no further remedial activities.  A Post-Remediation Care Plan for conducting inspections and maintenance is detailed in the Final Report dated November 2015.

During the Building 23 investigation, 1,2-DCA,1,2 dichloropropane (1,2-DCPP) and chloroform in soil exceeded the screening values for potential risk for vapor intrusion to indoor air.  A further investigation directly sampling the indoor air quality found no constituents above health-based levels for indoor air.

The 2015 Building 23 Area Final Report received PADEP Act 2 approval on January 26, 2016. 

Use Restrictions – In Progress

BASF is working with PADEP to modify the July 2016 Environmental Covenant in order to incorporate Building 23 Area and its associated Post-Remediation Care Plan.

Residential Parcel

The residential parcel of the property is an approximate 1.5-acre parcel that encompasses administrative (formerly residential) buildings as well as landscaped and parking area.  Between 2012 and 2014, a focused environmental investigation and remedial actions were performed in the southern portions of the site.  This area meets PADEP’s Residential Statewide Health Standards and received PADEP Act 2 approval on September 29, 2015.  As this area no longer requires land-use restrictions, BASF worked with PADEP to modify the July 2011 Environmental Covenant to remove this area from site property that will conform to non-residential land-use restrictions.  This new Environmental Covenant was recorded on July 21, 2016. 

Ballfields

Cognis sold approximately 18 acres to Lower Gwynedd Township and the Borough of Ambler in 2002.  The divested parcel generally included land situated to the northwest of Mathers Road.  Approximately 2 acres of this area was filled with various construction/demolition debris by Cognis predecessors between 1950 and 1980.  In 2000, an investigation was completed, concluding that there were no unacceptable risks to a select list of pollutants.  After review of facility files, a further investigation was performed in 2005 to assess whether additional parameters, including dioxin and pesticides, were at the parcel.  The investigations show that the parcel meets PADEP’s non-residential health standards. 

Volatile organic compounds above screening levels for potential indoor air were not found in the Ballfields investigation therefore, potential vapor intrusion is not a pathway of concern for this area.  A Final Report for the Ballfields was submitted in 2006.  PADEP provided Act 2 approval on May 03, 2006 for work associated with the 18 acres transferred to Lower Gwynedd Township and the Borough of Ambler. 

Use Restrictions – In Progress

At this time, BASF, Lower Gwynedd Township, and the Borough of Ambler are working with PADEP to execute an Environmental Covenant for the property to ensure non-residential land-use. 

Groundwater

Groundwater beneath the property has been evaluated since the early 1990s for VOCs, SVOCs and metals.  Certain VOCs; 1,1-Dichloroethene, 1,2-DCA, 1,2-DCP, trichloroethene, were found in the overburden and shallow bedrock aquifers above Maximum Contaminant Levels (MCLs) for drinking water.  1,2-DCA is the primary contaminant, and in 2007 was found at levels above 100,000 ug/l in the shallow bedrock aquifer, at the source area near the former Tank Area 3.  The MCL for 1,2-DCA is 5 ug/l.  Other compounds which are related to 1,2-DCA (products of degradation) were also found above MCLs, however at much lower levels and in smaller areas within the larger 1,2-DCA plume. 

Two types of treatment technologies have been employed at the site to address the contamination.  The first phase consisted of low-flow extraction and ex-situ ozone-peroxide treatment of contaminants from the shallow bedrock aquifer.  This step removed much of the most highly contaminated parts of the plume.  However, it was determined that this technology would be inefficient in remediating the remaining contamination.  This first phase was carried out between 2007 and 2011.

The second phase used hydraulic and pneumatic fracturing in conjunction with in-situ injections of a biodegradation product which stimulates chemical reduction of organic contaminants.  The effectiveness of this second phase, started in 2010, was evaluated periodically to determine if modifications were needed to the system.  Subsequent sampling showed 1,2-DCA levels as well as the size of the plume were decreased significantly.  In 2012, the most contaminated well showed a level of 76,000 ug/l and the extent of contamination was reduce by half from 2007.  In 2018, the most contaminated well showed a level of 4,200 ug/l and the plume extent was reduced significantly. 

Sampling in 2018 shows the overburden aquifer wells meet drinking water standards for 1,2-DCA and other associated contaminants.  Three (3) weathered rock wells adjacent to the former source area show several volatile organic compounds slightly above their drinking water standards.  Several shallow bedrock wells showing 1,2-DCA and other associated contaminants above drinking water standards were mostly located within 200 feet of the source area.  Annual monitoring across the site is planned to determine if the remedial strategy continues to reduce contaminant plume concentration and size.

On-site exposure evaluation

In 2018, groundwater results show that the overburden aquifer does not exceed the screening levels for potential indoor air pathway across the site, other than directly adjacent to the former source area.  These impacted wells are located more than 100 feet from all existing buildings on the Site.  Therefore, potential vapor intrusion for on-site buildings is not an exposure pathway of concern.

The 2018 sampling shows that the plume is contained within the property boundary and does not extend off-site.  There is no current exposure to groundwater, as all wells are used solely for environmental monitoring purposes.

Off-site exposure evaluation

In 2013, BASF submitted a summary and discussion of the potential indoor air pathway for off-site buildings.  At the downgradient property boundary, all volatile organic compounds in both overburden and bedrock wells are below the screening levels for potential volatilization to indoor air; demonstrating that off-site building vapor intrusion is not a pathway of concern. 

Historic PADEP sampling has shown 1,2-DCA is not found above drinking water levels in off-site wells downgradient of the Facility.  This demonstrates there is not an off-site component to the groundwater plume or potential for off-site exposure to site contaminants.

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Site Description

Interactive map of BASF (Formerly: Cognsis Corporation), Ambler, PA

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BASF currently owns a former metal-treatment and herbicide/pesticide manufacturing facility located in Ambler, Pennsylvania. One or both of these operations were generally performed between 1914 and 2003. Since then, operations have been reduced to specialty laboratory work in one building and general business and site-support services throughout the remainder of the property.  This Site was originally 44 acres, however the 2002 sale of the 18-acre Ballfields to Lower Gwynedd Township and The Borough of Ambler reduced the property to 26 acres.

BASF, Cognis, and previous owners have directed several environmental investigation and/or remedial activities at the Ambler facility between the early 1980s and present. Several of these voluntary actions were performed under oversight by the Pennsylvania Department of Environmental Protection (PADEP).  PADEP’s Release from Liability under Pennsylvania’s Land Recycling and Environmental Remediation Standards Act (Act 2) program was received for various parts of the Site, as described in the sections above.

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Contaminants at this Facility

Groundwater beneath the property has been evaluated since the early 1990s for VOCs, SVOCs and metals.  Certain VOCs; 1,1-Dichloroethene  (1,2-DCE), 1,2-Dichloroethane (1,2-DCA), 1,2-Dichloropropane (1,2-DCP), trichloroethene (TCE), were found in the overburden and bedrock aquifers above Maximum Contaminant Levels (MCLs) for drinking water.  1, 2-DCA is the primary contaminant, and in 2007 was found in the bedrock aquifer, at the source area near the former Tank Area 3.   Also several pesticides, naphthalene, dioxin and arsenic exist at levels above the applicable Statewide Health Standards in the Building 14 Area and Building 23 Area.

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Institutional and Engineering Controls at this Facility

    An environmental covenant dated June 20, 2011, and updated July 21, 2016, requires BASF or any future owner of the property to restrict land and groundwater use activities to those compatible with non-residential, land-use categories. In addition, the covenant requires inspection, maintenance and record-keeping of the integrity of the engineered cap that overlies Building 14 Area.  PADEP and BASF are working to modify the covenant to incorporate inspection and maintenance of the engineered cap the overlies Building 23 Area.  In addition, BASF, Lower Gwynedd Township, and the Borough of Ambler are working with PADEP to execute an Environmental Covenant for the property to ensure non-residential land-use of the Ballfields. 

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    Land Reuse Information at this Facility

     The site has an unused and reused parcels.

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    Site Responsibility at this Facility

    Resource Conservation and Recovery Act (RCRA) Corrective Action activities at this facility have been conducted under the direction of EPA Region 3.

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