FormGiven the direction of water flow, the primary concern for water contamination is the Providence River to the east. The nearest community and non-community water system wellhead protection areas are located west of 360 Eddy Street at distances seven and five miles, respectively.
FormWith this in mind, what kind of remediation is being conducted, what is appropriate, and what factors need to be considered?
THE CURRENT REMEDIATION PLAN
FormIt appears that capping of soil will be the primary means of dealing with remediation at Dynamo House. This will protect occupants of the site from contamination, but it raises the issue of whether contaminants beneath the cap will migrate to the waterway without due attention. Seth Handy, Dynamo House development director for Struever Bros., says that the traveling of contaminants beneath the cap is certainly of concern, particularly since the property is not far from the surface water level, and because water table changes. DEM is concerned with stabilizing the situation given historical land use and the nature of contamination, and the assumed risks posed to both human health and the environment. Mobility and toxicity of contaminants will influence how the agency applies remediation strategies. See also: Redevelopment Implications
FormContamination has been present on the parcel for some time and has not, to the knowledge of the developer and environmental consultants, “gone anywhere yet.” However, there is speculation that contamination by PAHs found on Dynamo House’s western property boundary traveled from offsite, suggesting that at least one contaminant may continue to migrate toward the river, and, one can assume based on groundwater flow patterns, will ultimately end up there.20 The emphasis on capping the soil without thoroughly understanding what will happen underneath seems to ignore this possibility.
HOW LIKELY IS IT THAT CONTAMINANTS WILL TRAVEL TO THE RIVER?
FormThere are a number of classes of TPH [Link to http://www.atsdr.cdc.gov/toxprofiles/phs123.html] that behave differently in soil and water. Certain kinds of TPH will travel to groundwater and dissolve into it. TPH behaves differently in water depending on its weight; some TPH compounds will form thin surface films, while others will accumulate in sediment and settle to the bottom of bodies of water. Still others will cling to soil particles and may stay in one location for a long period of time before being broken down by microorganisms.
Given that the GZA 2002 sampling found decreased levels of TPH in most samples from the 2001 report, if these results are assumed to be accurate, then there is the possibility that either the TPH was broken down on the site, or that it has began to travel, or some combination of the two. The second possibility should be alarming and warrant further investigation before a cap is immediately implemented.
PAH {link to http://www.atl.ec.gc.ca/epb/envfacts/pah.html} can also enter the water, either through runoff or by dissolution into groundwater. PAHs are slow to degrade in the environment and tend to accumulate in soils, sediments or in tissues of marine organisms.
WHAT RISKS SHOULD WE CONSIDER?
FormIf contaminants may indeed travel to the river, the seriousness of such a scenario should not be understated. Levels of PAHs, TPHs and heavy metals may be comparatively low in the developer assessments. In some concentrations, these substances pose dangers to wildlife and potentially to human beings through the food web and other pathways of exposure. Link back to known contamination page.
FormNote: This section is not intended to be alarmist or to suggest that contamination at Dynamo House may be having the following effects. However, it is worth knowing what effects on wildlife and human health might be associated with prolonged exposure to PAHs and TPHs, because it will inform the decision to use or not use a precautionary principle in dealing with these contaminants.
A WORD ON PAHS
PAHs are associated with fossil fuel combustion and petroleum products, and are known to concentrate at the surface of seawater, with implications for aquatic biota.
PAHs can bioconcentrate in organic tissue throughout the environment, posing the possibility that small concentrations may ultimately affect life in unexpected ways.
PAHs may increase in potency in the environment if combined with each other or with other pollutants.
PAHs have effects on marine life after prolonged exposure to lower levels. PAHs affect early developmental stages of creatures in the surface of seawater, according to Canada’s environmental agency Environment Canada and studies reviewed by the World Wildlife Fund. These effects include: impeded development of larval crustaceans, risk to benthic organisms, weakened sperm quality, female reproductive dysfunction, effects on fish egg production, and decreased levels of male hormones in fish. World Wildlife Fund reported that lower fish recruitment was found outside waterfront petrochemical complexes than outside other sites.
PAHs have been found to be carcinogenic in animals at certain concentrations and, most recently, to interfere with hormonal systems with effects on reproduction and development, as well as weakening of immune function. Although levels of PAH found onsite are below levels of immediate concern, the bioconcentration and increased potency factors may create such a concern in the future. Additionally, given the demonstrated potential for bodily harm to animals, including humans, at certain concentrations, there is always the possibility that less evident or immediate health effects may develop, about which scientists and policymakers are not yet aware. In other words, can we determine what a “safe” level of PAHs should be?
A WORD ON TPH
TPH should be treated with the same initial caution. Some compounds have been proven to affect the human central nervous system, especially through extended exposure. There have also been links to cancer. A good summary of the potential health effects of TPH can be found here:
http://www.atsdr.cdc.gov/toxprofiles/phs123.html#bookmark05
RI Standards for Hydrocarbon Contaminated Soil Direct Exposure Criteria (Residential & Industrial/Commercial)
(see table below)
a These Direct Exposure Criteria for contaminated soils are only applicable to sites managed under the RIDEM Rules and Regulations for the Investigation and Remediation of Hazardous Material Releases (Remediation Regulations), as amended August 1996. Sites with hydrocarbon contaminated soil resulting exclusively from a Leaking Underground Storage Tank (LUST) are managed by the RIDEM LUST Program on a site by site basis.
b Preferred lab analytical test methods are recommended in the Remediation Regulations, but not specifically required. Sites managed under the LUST Program should refer to the RIDEM UST Closure Assessment Guidelines for specific required lab analytical test methods.
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