; Scofieldtown Road Aquifer Contamination INFORMATION SUMMARY and GENERAL REFERENCE GUIDE
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Scofieldtown Road Aquifer Contamination INFORMATION SUMMARY and GENERAL REFERENCE GUIDE

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									Scofieldtown Road Aquifer Contamination

INFORMATION SUMMARY and GENERAL REFERENCE GUIDE

Prepared for: Michael Pavia September 24, 2009

Prepared By:

t.a. Brigante, p.e.a., and associates, llc
............a business unit of the orion companies............

Purpose and Rationale This broad spectrum information summary was prepared in response to a series of general inquiries from residents affected by the discovery of RCRA listed chemicals in the

local aquifer/water supply resource for the Scofieldtown Road, Stamford, Connecticut residential area. Of particular importance, it should be stated, and acknowledged that this information/document is does not constitute a critique, contradiction, or technical challenge regarding the current mitigation strategy developed by the City of Stamford, Connecticut in response to this specific condition. The specific intent of this overview is to provide a fully qualified review of the condition, a cursory review of all data generated since the inception of surveillance activities in the affected neighborhood(s), and to offer a foundation of technical information from which affected parties may draw to assess their individual levels of potential exposure. Declaration of Stated Conditions Based on the data available to reviewer(s), it has been established that the primary bedrock aquifer underlying the Scofieldtown residential area has been contaminated with chlordane (C10H6Cl8 ), dieldrine (C12H8Cl6O), and possibly other organic/halogenated hydrocarbon waste products. The suspected source of this contamination appears to be the former Stamford Landfill, situated in the geometric center of the Scofieldtown neighborhood, north of CT Route 15, in Stamford, in southwestern Connecticut, near exit 37 (see attached quadrangle plan-view imagery). Chlordane is commonly known as a pesticide, derived from hexachlorocyclopentadiene, and Dieldrin is a chlorinated hydrocarbon originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide, or pesticide. in

Chlordane was restricted in 1982, and banned completely in 1988, by the US Environmental Protection Agency its potential as a systemic carcinogen. The previously referenced landfill has not yet been definitively established as the sole source of this contamination, and because these particular compounds were widely and commonly used by both the commercial sector and the private sector as a pesticide for nearly forty years, it would not be imprudent to consider one, or several individual residential point-sources for these specific compounds in the subsurface. Previous, similar scenarios have been traced back to a specific residence, wherein the estate of a given decedent included a minor inventory of both chlordane and dieldrin, typically stored in the garage or basement, prior to the Federal ban on the possession of this chemical compound(s). Following the Federal ban, hardware stores with pre-ban accumulated residual inventories sold small quantities of both pesticides to local retail consumers on an informal basis on demand. Many retail consumers in the US stockpiled these highly effective chemical pesticides in garages and basements for anti-termite control around house foundations. Upon the liquidation of an estate that included these minor quantities in storage, family members would occasionally dump the liquid contents into a dry-well, hand-dug pit, or other geologically accessible earthen breach, simply to dispose of the stockpiled materials. Many such incidents have been traced back to residential on-site disposal of an estate inventory. (USEPA) due

While the former Stamford landfill is the most obvious potential source of this contamination, it should not be automatically assumed by the affected populace that is the only potential source in the neighborhood. General Geologic Setting Because the apparent chemical encroachment into the area water supply is governed by geologic and hydrogeologic dynamics, it is important to understand the basic profile of the geologic mechanisms governing the transport, migration, and geometric distribution of the chlordane/dieldrin plume. In southwestern Connecticut, the surficial (surface-zone soils, rocks, and deposits) geology is comprised chiefly of glacial deposits, commonly referred to as glacial till. Glacial deposits are generally heterogeneous......meaning they are random in composition, thickness, and areal distribution. In the subject quadrangle, glacial deposits range in thickness from 8 (eight) to more than 50 (fifty) feet. Glacial deposits are merely the rocks, rock fragments, soils, and various substrate materials accumulated during the last ice age, when the Great Borealis glacier pushed its way south and east, and came to rest along the New England coastline. When the glacier melted, these rocks and gouged earthen materials were dumped at the leading edge of the ice-mass, leaving New England with a randomly rocky coastline, interspersed with veins of sedimentary deposits. Long Island Sound formed a post-glacier erosion basin, through which the finer sediments (sand, gravel, and silts) were carried off of the melting ice-mass. A huge sand bar, known as a terminal moraine, or Long Island, New York, bounds the Connecticut coastline to the south, the

furthest land/sea interface resting just 12 miles from Bridgeport, Connecticut. Long Island, than a large sandbar, New York is little more comprised chiefly of sand, gravel, and

silts that accumulated from the melt-waters of the receding glacier. The marked difference between the southern New England coastline surficial geology and the fine, sandy depositional composition of Long Island can be easily distinguished by visual observation. This phenomenon is important in this case, because it creates an understanding of the fluid-dynamic characteristics governing groundwater flow on the Connecticut side of Long Island Sound, wherein the subject geologic quadrangle is situated. Groundwater occurs virtually everywhere below land surface in Connecticut. In some locations this groundwater is distinguished between an unconfined water table aquifer (within the glacial deposits), and the deeper bedrock aquifer in the consolidated, or bedrock formation that forms the foundation for the glacial till dumped here by the glacier millions of years ago. Bedrock in Connecticut is either sedimentary, igneous, or metamorphic in origin. There are no major faults, or significant layering chasms, in the primary area of interest. The current, primary areas of interest include properties along Cousins Road, Lakspur Road, Hannas Road, and Symeadow Drive from Scofieldtown to Lakspur Roads. The dominant underlying bedrock is the Trap Falls and/or Ordovician granitic gneiss formation, which is comprised of schist, gneiss, or mica-schist. The Trap Falls

formation may be part of, or contiguous with the Golden Hill Member schist which is a silvery-gray, weathered, and medium grained and a generally well-layered schist. Schists are typically characterized by highly weathered fracture zones in both the vertical and lateral profiles, depending upon the strike and dip orientation of the underlying consolidated geologic formation. Commonly available measurement tools (Brunton Compass, surveying equipment, etc.) can be used at surface outcrop exposures of the local bedrock to determine the strike and dip, and hence locally important faulting characteristics in the Scofieldtown-area bedrock quadrangle. The Ordovician (?) granitic gneiss (Og) (including local terms Ansonia, Mine Hill, Tyler Lake, Siscowit) commonly contains numerous inclusions or layers of mica-schist, two (2)micagneiss, and is white, light gray, buff, or pink in color. This is generally a foliated granitic gneiss, composed of sodic plagiocase, quartz, microline, muscovite, biotite and garnet. The technical understanding of the underlying bedrock formation is critical in this particular case, because it allows a general characterization of the aquifer-flow dynamic mechanisms responsible for the distribution, geometry, and geologic trending of the chlordane/dieldrin soluble plume, if indeed the plume is comprised of only these two compounds, which frankly, under the circumstances, is highly unlikely based on the potential point-source potentials. Contaminant Source(s) Discussion

Because the current data suggests an absence of real-time geologic sampling and characterization, several assumptions must be made at this particular juncture:  The source of contaminants must be, of necessity, perched in the overlying unconsolidated, or glacial till deposits overlying the previously described bedrock formation. This assumption is based on the pragmatic conclusion that the chemical(s) were either dumped, buried, or poured into the soil materials (unconsolidated-zone, glacial till) at either the landfill site, or a nearby residential parcel. Very seldom would the deposition of chemical waste occur by blasting an open hole in bedrock, and placing contaminants, or contaminant-bearing containers (drums, 5-gallon pails, powders, liquids) beneath the surface of a bedrock exposure. In other words, human behaviors generally did not include excavating through bedrock (ledge) to bury unwanted chemical or bulky waste materials.  The chemical contaminants may be remnants, or contents leaking from corroded barrels or containers buried either in the landfill, or poured/buried/dumped at a private residence in the local subject area.  The glacial-till overburden (soils, rocks, boulders, etc.) typically contains an unconfined water table aquifer, that is hydraulically connected to the underlying bedrock aquifer formation, within which most potable wells in the area are constructed. Drinkingwater, or potable-supply wells at each residence in the affected area are typically constructed in such a way that seals off the shallow water table aquifer above the

bedrock surface, with a solid steel casing of 6-inch diameter or greater (rare), driven a minimum of ten feet into the consolidated, or bedrock formation. Properly constructed wells also incorporate a tremie-grout (pumped under pressure) sealant to isolate the overburden water, and any contaminants therein, from entering the deeper bedrock aquifer via borehole annular space migration. Most water-supply (potable water) wells are merely a random length (depending on glacial-deposit thickness at the drilling site) of steel casing, driven through the soil and glacial deposits, and into the competent, consolidated bedrock material underneath. The borehole, or production well, is generally a self-stabilized open boring that intersects water-bearing fractures in the bedrock. Because most New England bedrock is of sufficient structural integrity to remain open without the use of casing or annular-shoring, a well-screen device is typically not necessary to prevent the borehole from collapsing. The final potable well is essentially a random length of six-inch steel casing pounded or hammered through the soil, and into the bedrock at least ten feet, followed by an open, six-inch borehole drilled by either mechanical percussion, or cable-tool installed (chop and wash), or pneumatic-hammer drilled, drilling rig. air-rotary In some geologic settings in New England

and around the continental United States, water-supply wells are constructed in the unconsolidated formations above the bedrock. These production wells are usually built in high-yield stratified drift geologic deposits with enormous capacity, storativity, and aquifer-recharge characteristics. Some cities and towns in Connecticut use

this type of production well, constructed in fullyexplored and studied sand and gravel aquifers with sufficient replenishment recharge sources (rivers, streams, and lakes) to sustain the continuous mining of fresh water for human consumption. This is typically not the case in southwestern Connecticut, because of the specific geologic conditions common to this particular locality  Because of the nature of the Trap Falls and Golden Hill Member bedrock material (weathered schist, layered and fragmented), there is reasonable cause to suspect that waste products buried, or located in the unconsolidated (glacial deposits) overburden somewhere in the area have migrated vertically to the unconfined (glacial) shallow water-table aquifer, which in turn is hydraulically linked (via fractures and weathered interface zone(s)) near the contaminant source-area.  Source-area contamination migrates as a function of several variants related to fluid dynamics in geologic formations. These two particular contaminants, chlordane and dieldrin, are relatively insoluble, however, exposure time, vertical migration components specific to the geologic setting in which they were deposited, and bedrock-interface characteristics (weathered, fragmented, and highly conductive) has apparently caused these chemicals to enter the deeper bedrock fracture network, from which area wells draw daily water supplies.  Regardless of where the known contaminants have entered the deeper water-supply potable-use bedrock aquifer, continuous pumping of residential wells in the neighborhood create a hydraulic cone of depression, or

lowering of the ambient aquifer equilibrated fluid surface, and cause continued migration of contaminants into this sphere of hydraulic depression. Some residents use more water than others. Those that do pump their wells excessively in response to the demands of domestic use, have deeper, or more susceptible well-supply systems, simply because their particular cone of depression is greater than their neighboring users.  Collectively, the affected residential wells represent a hydraulic-vortex, or hydraulic-depression in the bedrock aquifer, which will induce continued, and dyamic (changing) levels of various contaminants into their supply systems over time. Further, it is nearly impossible to measure ambient aquifer (bedrock and/or glacial) hydraulic-gradient characteristics while the affected residents continue to artificially influence natural aquifer flow characteristics simply by showering, flushing toilets, watering lawns, or doing laundry. Every time a home calls for water-demand in this way, their individual well activates, and is pumped in linear correlation to the momentary demand. Collectively, this demand (across 16 affected homes), has caused a depression that will capture, and continue to draw contaminants into the zone of influence already affected by chemical encroachment. Potable-Water Supply Safety Protocol-Discussion The use of activated charcoal filtration (GAC, or granulated activated carbon) at each supply point (each home/residence) is somewhat problematic from several perspectives, as follows:

 While GAC (see above) is fairly effective in removing chlordane and dieldrin by adsorption (not ABSORPTION), the design criteria necessary to establish adequate retention time (how long activated carbon particles are in contact with contaminated water), influent concentrations (or the levels/concentrations of target compounds) are dynamic, and may change hourly based on demand, source leachate characteristics, and the effects of precipitation and area recharge dynamics.  Depending on the frequency of sampling and analysis, it is nearly impossible to determine when a carbon bed reaches breakthrough, or is at its maximum chemical retention threshold. Therefore, if a system is scheduled for both influent and effluent sampling and analysis on a bi-weekly basis, but the carbon bed has reached breakthrough, or maximum adsorption potential, then the residents may have been exposed to chlordane and dieldrin levels for an unknown period of time, between carbon filter changes. ADSORPTION, is the ability of a charcoal particle to catch soluble organic compounds by attracting these molecules to cling to the surface of each individual charcoal particle (molecular affinity). The interstitial spaces, or pore spaces between each particle, must remain full of organic-compound-bearing water for a very specific amount of time to assure complete adsorption. It is nearly impossible to accurately measure the usage dynamics, influent concentrations (accelerated by continuous hydraulic depression) of each individual system on a daily basis, therefore, is not an economically or logistically viable interim solution. While activated charcoal (GAC)

represents a reasonable safety net to minimize the potential exposure of residents to excessive levels of chlordane/dieldrin, it most certainly is not a viable long-term, interim, or permanent solution to the baseline aquifer impact condition at the Scofieldtown site, for all the reasons stated above, and more.

Condition Mitigation Alternatives - Discussion It is understood by the formulators of this document that a separate, publicly controlled water supply system is located with 2000 feet of the affected area. In lieu of attempting to safely regulate the influent, treatment, and effluent (water consumption/usage) of each supply system, it would be recommended to ascertain the viability of establishing an overland, guaranteed-potable water supply until a permanent water supply network can be brought into the neighborhood, probably next spring. This overland, temporary supply system would provide a continuous, potable-quality water supply for affected residents, while concurrently allowing the bedrock aquifer to reach ambient equilibrium, so the natural hydraulic gradient in both the overburden and bedrock aquifers can be measured and evaluated. Further, the expense-management dynamics associated with individual GAC filtration, sampling, and analysis at each residence may actually be more expensive, and less effective as a public-safety solution than several alternatives available for this particular scenario.

A temporary, overland water supply system would be comprised of a single 6-inch ABS pipeline brought overland to the neighborhood, protected against vehicular damage, freezing conditions, and pressure requirements using conventional methods and materials currently available in the commercial sector. The 6-inch main would then be manifolded at the point of entry to each residence with a lateral 3/4-inch feed line, piped directly to each residence supply system, typically located in the basement of most New England homes in the area. Again, these laterals would be protected against damage, freezing, and pressure demand dynamics using conventional apparatus available in the commercial sector. This supply alternative should be in place, and in use until a permanent subsurface main-supply pipeline can be installed according to City specifications.

The use of this interim approach provides the following benefits, currently not present using the present GAC filtration protocol:  The water supply system can be monitored at a single point-source by local utility specialists managing public water quality in Stamford.  There will be no variation in chemical concentrations, GAC effectiveness per-unit, or special handling/usage adaptations for affected residents.  The current artificial (created by daily, continued pumping of individual wells) hydraulic depression which accelerates chemical encroachment will return to ambient

conditions, thereby allowing effective and accurate measurement of aquifer dynamics, and exploration of the point-source location of chemical leachate. Additional Observations - Potential Concerns Currently, based on the data made available through the information system posted by the City of Stamford, the chemical compounds being targeted for analysis constitute a small fraction of the potential chemical contaminants that may be present in the overburden sediments in the subject area. In addition to the halogenated compounds (chlorinated hydrocarbons), or oil-based chemicals that can be found in most former bulk landfill sites) aquifer-quality analysis should also include eight RCRA heavy metals, and a wide variety of other contaminants that have not been included in the water matrix analytical suites presently applied. It should be noted that adequate probable cause exists to expand a few random sample/analysis for other potential contaminants, in addition to chlordane and dieldrin. This information is critical in order to understand if the landfill area is indeed the point-source for this encroachment phenomenon, and if other RCRA regulated compounds/pollutants have also impacted the aquifer. Some of these compounds, typically found in CERCLA (Superfund) sites are not always effectively treated with GAC alone. For example, PCB, or former transformer cooling fluids (Aroclor, etc.) are typically insoluble in water alone, unless they are exposed to other chlorinated compounds such as TCE, PCE, and other common industrial solvents. It is paramount that an expansion of analytical protocols be implemented to include the variety, and composition of the various pollutants that may be present in

an abandoned landfill area. The USEPA has developed a standard analytical protocol for testing for such potential, which is currently not, based on the data reviewed, being executed with the sense of urgency it demands for public safety. Source Mitigation - Discussion In order to understand the location, vertical positioning, and leachate potential of the target compounds, and others that may be present, a series of shallow borings should be installed at strategic points relative to the landfill geometric configuration. Once located and fully delineated, the adsorbed phase, or mass of contaminants in the landfill (or alternate) overburden can be characterized both laterally, and vertically, and a decision can be made regarding the remediation, or stabilization of this leachable contaminant mass. Several reasonable options exist to mitigate continued aquifer encroachment by leachable chemical wastes in the subject area. Many technologies exist to either solidify/render stable, remove, or pneumatically, hydraulically, or biologically attenuate chemical adsorbed mass either in the landfill, or at the point-source location. Fate and Transport Analysis Once the overburden source of contamination is fully delineated and understood, the transfer mechanism between the adsorbed chemical mass (saturated sediments above the bedrock) can be evaluated using conventional pump tests, hydrogeologic evaluation, and multiple variants thereof. The next phase of

assessment should be to fully understand ambient bedrock flow dynamics in both the vertical and lateral profiles. Using several common isopleth (concentration gradient analysis) concentration correlative technologies, the scope, dimension, composition, and three-dimensional geometry of the leachable chemical mass should be extrapolated, measured, and fully delineated. This data can be used to prepare a standard FATE AND TRANSPORT predictive computer model, which will predict where this plume will be in 6-months, one year, five years and ten years, under ambient or dynamic conditions, depending on input data. This information will be essential to the planning, logistics, pro forma, and timeline associated with bringing a quality-assured public water supply to the currently affected area, and areas that may be impacted over time. Fate and transport modeling is commonly used by regulators, and industry when dealing with scenarios of this magnitude and dimension. It can be combined with RBCA, or Risk Based Corrective Action protocols, which essentially predict the sensitive down-gradient receptors (homes, wells, supply systems) that may be affected over time. This information is used to guide the level if mitigation activities and the expenses associated thereto. Halogenated compounds, unfortunately, do not naturally bioattenuate as quickly as straight-chain hydrocarbon products, simply because they are not easily metabolized by indigenous bacteria that exist in the bosom of Mother Earth herself. Eventually, however, the environment will metabolize these

chemicals, converting them to carbon dioxide and H20, over time. The half-life of some of these synthetic chemicals, however, can be hundreds of years, and in the interim, can affect human health and the environment in an egregious and deleterious way. All of these factors must be considered to preclude a widespread evolution of the currently identified halogen plume, and to effectively plan for the remediation protocols that must, of necessity, be implemented to protect human life and the environment as a whole. The favorable news, at the conclusion of this overview, is that this particular paradigm has been effectively managed, and resolved, in the course of the last 30 years in the environmental technology development and pioneering era. These advances in technology, management protocol, and technical manipulation have evolved to the point of routine for a small collective of remediation/solution oriented professionals across the USA. The key to successfully managing this condition is to allow a process of knowledge-based activity, linear technical thinking, and anecdotal solution archives to govern the course(s) of action selected to ameliorate the consequences of human encroachment in the natural environment. CREDITS The panel of professionals that represents the source(s) the material presented represent a wide, and deeply credentialed fraternity of industry scientists, engineers, University Professors, medical professionals, and remediation for

specialists who have dedicated their careers over 30 years to this very specific environmental-impact phenomenon. The body of work created by this history includes direct involvement with numerous similar scenarios such as Love Canal, Chemical Control New Jersey, CERCLA (Superfund remediation), and numerous private impact scenarios funded, and resolved by Fortune 500 companies. Most of the professional network is available for collaboration, consultation, and mitigationstrategy development and implementation at the direct request of Michael Pavia, and staff, as well as the City of Stamford, Connecticut. As a technical guidance resource, this network has been made available to Mr. Pavia upon demand, and is currently offered pro-bono in the interest of assisting the City of Stamford, the State of Connecticut (currently grossly understaffed due to economic conditions), the Stamford Health Department, and any and all residents who need information and technical understanding on an interpretive or remedial implementation level.

t.a Brigante, p.e.a. & associates, pc, llc
..............a business unit of the orion companies.........

ORION EARTH SERVICES Corporation

Orion-surgex environmental technologies Orion hydrodynamics corp. Orion marine preservation technologies

Phalanx global environmental preservation technologies

t..a. Brigante, p.e.a. & associates, llc.

Thomas a. Brigante, p.e.a.

Principal environmental analyst

Credits/credentials

Founder/ceo or Principal Environmental Remediation analyst: New England pollution control company, inc./it corporation subsidiary (nepcco) 1974-1984 (co-founder, director of geotechnical remediation services) Land tech remedial, inc./handex environmental technologies, inc. (1986-2000) Orion earth services corporation (2000-2009) (former or current strategic alliance contractors, usepa, us coast guard, nys department of environmental conservation, ct dep., nj dep,

Network advisory panel

Thomas a. Brigante, p.e.a., ceo, phalanx global, t.a. Brigante, p.e.a. & associates

Timothy douthit, ms.,cpg, executive vice president, chief science officer, ltr, inc. j. Thomas pinto, phd., nyu medical university
organic chemistry/molecular biology

russel dirienzo. L.e.p., lfr, inc./arcadia environmental - section/unit manager Nicholas burkun, environmental scientist, Norwalk wpca


								
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