5.0 Risk Assessments of Areas of Concern on Site

5.1  Soil – Risk Assessment

Three potential pathways for human exposure for chemicals present in soil include: 1. incidental ingestion, 2. dermal absorption from contacted soil, 3. suspension of chemicals volatilized in soils into the air and then inhaled.  Contaminants present in Site soils such as PCBs have the potential to be carcinogenic if ingested or absorbed; while others, such as lead, may produce noncarcinogenic effects.  Under the current Site conditions, individuals who trespass on the Site may be exposed to the chemicals contained in Site soils.  Off-site soil may contain chemicals originating from the Site if suspension into the air, followed by deposition onto nearby ground surfaces occurred.  Children playing in nearby playgrounds or yards could be exposed to site-related chemicals.

Wildlife inhabiting the Site may also come into contact with on-site contaminated soils.  Direct contact and incidental ingestion can affect borrowing animals, and dust bathers, such as many bird species. 

5.2 Groundwater – Risk Assessment

Components of groundwater could discharge to Crafts Creek.  Residents located 1,500 feet from Crafts Creek use private wells for their water supply and could potentially be exposed to chemicals migrating from the Site.  The Delaware River is also a drinking water source for cities of Burlington, as well as Philadelphia; chemical releases to the Delaware River from the Site could affect these drinking water supplies.  The Delaware River and the treatment system for municipal water supplies could mitigate the potential impact of these contaminants.

5.3 Surface Water and Sediment – Risk Assessment

Surface water transport involves run-off and storm sewer discharge into the Delaware River and Crafts Creek.  Run-off of eroded surface soils may also transport contaminants to the local waterways.  Individuals could be exposed to chemicals present in surface water as results of incidental ingestion and dermal absorption.  Indirect exposures include ingesting fish caught from Crafts Creek or the Delaware River, as well as consuming produce treated with irrigated water coming from either Crafts Creek or the Delaware River.  Individuals who may come into direct contact with sediment located in Crafts Creek or the Delaware River may be exposed to Site specific contaminants.   This may result in risks for ecological receptors, such as fish and wildlife using these water bodies.  Many chemicals are known to bioaccumulation in invertebrates and fish tissue through uptake in their gill membranes.  Therefore mammals such as raccoons and many bird species, are likely to consume possible contaminated invertebrate organisms, as well as fish.  The chemicals will then be ingested at higher levels within the ecological food chain. 

5.4 Air – Risk Assessment

Soil on Site is not well vegetated, limiting the amount of ground cover, therefore providing pathways for wind suspension of soil particles.  Movement of vehicles may also suspend these particles into the air, and carry them to off-site receptors via wind transport.  The baghouse dust located on Site, has a higher potential of transport due to the fine nature of particles, and present a higher ability of suspension than that of soil particles.  Under present Site conditions, residents of Roebling may be exposed regularly to chemicals potentially emitted from the Site.