Contamination Issues and Soil Health in Urban Forestry
Nicholas Dickinson, Liverpool John Moores University, Liverpool, UK
Christopher French, Liverpool John Moores University, Liverpool, UK
Philip Putwain, University of Liverpool, Liverpool, UK

Spatial Distribution of Total and Methyl Mercury in Stream Sediments at Superfund Site
Dorothea Seth Richardson,CDM, South Plainfield
Joseph J. Mayo, CDM, South Plainfield, NJ
Demetrios Klerides, CDM, New York, NY
Thomas Taccone, U.S. Environmental Protection Agency, Region 2,New York, NY

Effects of High pH on Metals Mobility in Groundwater
Purshotam K. Juriasingani, Tetra Tech NUS, Inc., Oak Ridge, TN 
Richard W. Arnseth, Tetra Tech NUS, Inc., Oak Ridge, TN
Michael Albert, Tetra Tech NUS, Inc., Oak Ridge, TN
Terry Hansen, Tetra Tech NUS, Inc., Tallahassee, FL 
Adrienne Wilson, Southern Division Naval Facilities Engineering Command, North Charleston, SC  

Review of In-Situ Remediation Technologies for Lead, Zinc, and Cadmium in Soils
Todd Martin, Integral Consulting, Inc., Boulder, CO  
Mike Ruby, Exponent, Boulder, CO  
Andrew Green, International Lead and Zinc Research Organization, Durham, NC

In-Place Closure of Industrial Waste Impoundments: A Case History
Linda M. Burke, NTH Consultants, Ltd., Farmington Hills, MI
John S. Browning III, The Mannik & Smith Group, Inc., Dearborn, MI 
Pamela M. Dodt, Ford Motor Land Services Corporation, Dearborn, MI 
Clifford V. Fleener, Visteon Corporation, Monroe, MI 
David S. Miller, Ford Motor Land Services Corporation, Dearborn, MI 

Assessment of Methylmercury Risk to Three Species of Wading Birds in the Florida Everglades

Darren G. Rumbold,  South Florida Water Management,  Mail code 4642, 3301 Gun Club Road,  West Palm Beach, Fl 33428,  Tel: 561-682-2132, Fax: 561-687-6442 

Mercury contamination is one of the more serious problems facing Everglades restoration.  Currently, the Everglades is under human health advisories for limited or no fish consumption because of methylmercury (MeHg).  In the Everglades, high concentrations of MeHg have also been found in top predators like raccoons, alligators, wading birds and Florida panthers.  This case study reports on a risk assessment that used both deterministic and probabilistic methods to provide managers with estimates of risk while explicitly quantifying uncertainties.  The objectives of this risk assessment were two fold: (1) to provide an Everglades-wide perspective of MeHg risk to wading birds, and (2) to address specific stakeholder concerns regarding possible adverse effects from restoration efforts currently under way in the Everglades.  The latter objective was achieved using a well-studied oligotrophic site as a reference site for post-restoration conditions for mercury methylation and bioaccumulation.  Exposures were based on measured tissue levels during 1997 – 1999 in fish species known to be consumed by wading birds.  Toxicity reference values (TRV) were obtained from the published literature.  Results suggest that birds foraging in the central basin were at greatest risk, with 86% of the great egret population expected to exceed the TRV.  By comparison, only 46% of the egrets foraging at the post-restoration reference site were predicted to exceed the TRV.  Model-predicted egg and nestling feather mercury levels exceeded measured concentrations by a factor of 1.4 and suggest that the Monte Carlo model overestimates mercury exposure to the birds.  Together with other lines of evidence, including reproductive studies, these results support the conclusion that the restoration effort will not increase MeHg risks to wading birds to unacceptable levels.  Alternatively, MeHg risk to wading birds foraging preferentially in the central basin, particularly when near MeHg “hot spots”, are of potential concern and warrant further studies.

Contamination Issues and Soil Health in Urban Forestry

Nicholas Dickinson, School of Biological and Earth Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK, Tel: +44-151-231-2190, Fax: +44-151-207-3224
Christopher French, School of Biological and Earth Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK, Tel: +44-151-231-2367, Fax: +44-151-207-3224
Philip Putwain, School of Biological Sciences, University of Liverpool, Nicholson Building, Liverpool L69, UK, Tel: +44-151-794-7789, Fax: +44-151-353-1004

The context of this paper is how and when we decide if a contaminated urban soil is healthy or not.  This is the current focus of our project that contributes to urban regeneration in North-West England through community forestry.  Dispersion patterns of metals are described and mapped at a range of urban brownfield sites, variously contaminated with trace elements including As, Cd, Cu, Ni, Pb, Zn and B, and planted in field trials with trees (biomass species of Salix and Populus, with Alnus, Betula and Larix).  Contaminant hotspots were targeted for experimental work; heavy metal mobility was quantified as the tree cover became established and for three growth seasons.  Although heavy metals and other trace elements exceeded guideline thresholds, toxicity to plants was seldom an important issue; significant toxicity to plants was only recorded in the cases of extremely high concentrations of B and As.  Attention is given to assessing the toxicity of hotspots in relation to working guidelines, and to risks of dispersal of contaminants into the wider environment.  Results are presented of efforts to influence hotspots through uptake and harvest of short-rotation coppice and using soil amendments.  Mass balance models are compared with datasets for more mature woodlands. Metal mobility is significantly influenced by soil conditions created by plant growth, rhizosphere processes, earthworm casts and the drilosphere (burrow walls).  Crude measures of metal concentrations in bulk soil are shown to be an entirely unsatisfactory way to describe soil health.  Accurate and realistic ecosystem models of elemental fluxes, and improved knowledge of soil ecology provide the key to recognising healthy soils.  We consider this an important step towards using accurate and realistic ecosystem models in restoration of sustainable and healthy soils to brownfield land.

Spatial Distribution of Total and Methyl Mercury in Stream Sediments at a Superfund Site

Dorothea Seth Richardson and Joseph J. Mayo, CDM, 107-F Corporate Boulevard, South Plainfield, NJ 07080, Tel: 908-757-9500, Fax: 908-757-9806
Demetrios Klerides, CDM, 125 Maiden Lane, 5^th Floor, New York, New York 10038, Tel: 212-785-9123, Fax: 212-785-6114
Thomas Taccone, U.S. Environmental Protection Agency, Region 2, 290 Broadway, New York, NY 10007-1866

From 1955 to 1998, Mercury Refining Company was engaged in the reclamation of mercury from a variety of sources including batteries, thermometers, electrical switches and dental amalgams.  The Mercury Refining Superfund Site, New York is located adjacent to an unnamed tributary to Patroon Creek, which flows into a major river approximately 5 miles downstream of the site.  In the past mercury from the site has reached the creek from a variety of pathways, including:  waste batteries that were dumped over an embankment to the tributary; surface water runoff discharged to the tributary; and fall-out from a fire in the Hand Shop building.  A remedial investigation/feasibility study (RI/FS) was initiated by the USEPA to determine the nature and extent of the contamination.  This paper focuses on the spatial distribution of total and methyl mercury in stream sediments downstream of the site and at background locations.  Mercury methylation ratios were examined to determine the areas of highest methylation occurrence.  In general, an inverse relationship between the total mercury concentration and the percent of methylation was observed.  Total mercury concentrations also showed strong areal correlations with total organic carbon, but little or no correlation to cation exchange capacity, pH or grainsize.  Total mercury also shows little correlation to total organic carbon with depth.  Three samples, located just downstream of the site, showed higher than expected methyl mercury to total mercury ratios.  These data may be reflective of higher sulfate concentrations in the stream water or anthropogenic effects on this portion of the stream system. 

Effects of High pH on Metals Mobility in Groundwater

Purshotam K. Juriasingani, Tetra Tech NUS, Inc., 800 Oak Ridge, Turnpike, A-600, Oak Ridge, TN 37830, Tel: 865-220-4753 Email: juriasinganip@ttnus.com  
Richard W. Arnseth, Tetra Tech NUS, Inc., 800 Oak Ridge, Turnpike, A-600, Oak Ridge, TN 37830 Tel: 865-220-4721 Email: arnsethr@ttnus.com
Michael Albert, Tetra Tech NUS, Inc., 800 Oak Ridge, Turnpike, A-600, Oak Ridge, TN 37830Tel: 865-220-4721 Email: albertm@ttnus.com
Terry Hansen, Tetra Tech NUS, Inc., 1401 Oven Park Drive, Suite 102, Tallahassee, FL 32312Tel: 850-385-9899 Email: hansent@ttnus.com
Adrienne Wilson, Southern Division Naval Facilities Engineering Command, 2155 Eagle Drive, P. O. Box 190010, Code ES31AW, North Charleston, SC 29406, Tel: 843-820-5582Email: WilsonAT@EFDSOUTH.NAVFAC.NAVY.mil

At the ambient pH in most groundwater systems, metal mobility is limited by solubility and sorption reactions.  Anthropogenic releases that dramatically alter the groundwater pH may produce a short-lived mobilization of naturally occurring metals. The presence of metals in groundwater with concentrations exceeding acceptable risk levels may cause a concern to human health and the environment.  Natural processes may offer effective in situ treatment of metals in groundwater.  Groundwater sampling at the Navy site illustrates the mobilization and slow return to normal in a coastal aquifer.  

In 1992, a sodium hydroxide spill occurred at the Neutralization Basin at Naval Station Mayport in Mayport, Florida.  Groundwater samples collected during a RCRA Facility Investigation (RFI) in 1994 indicated elevated concentrations of several metals including copper, iron, nickel, and vanadium. As part of the Corrective Measure Study (CMS), Tetra Tech NUS, Inc., evaluated the hypotheses that at high pH, the soil matrix became negatively charged and sorbed metals were mobilized in the form of complex anions.  It was further hypothesized that as upgradient groundwater naturally flushes the aquifer, the aquifer would return to more natural pH and the metals in groundwater will either precipitate or sorb to the aquifer solids.  The CMS proposed a sampling event to test the hypothesis.  The results of the groundwater sampling event conducted in August 2001 indicated that the concentrations of copper, iron, nickel, and vanadium (chemicals of concern determined in the CMS) were lower than the concentrations detected during the RFI.  The highest pH measured during August 2001 sampling event was 9.29 SU as compared to 11.4 SU measured during the RFI.  The results of the August 2001 sampling event indicate that naturally occurring processes will effectively remediate the site.

In-Place Closure of Industrial Waste Impoundments:  A Case History

Linda M. Burke, NTH Consultants, Ltd., 38955 Hills Tech Drive, Farmington Hills, MI 48331, Tel: 248-324-5264
John S. Browning III, The Mannik & Smith Group, Inc., 15300 Rotunda Drive, Suite 306, Dearborn, MI  48120, Tel:  313-271-2223, Email: jsb@msg-dearborn.com
|Pamela M. Dodt, Ford Motor Land Services Corporation, 550 Town Center Drive, Suite 200, Dearborn, MI  48126, Tel: 313-323-7808, Email: pdodt@ford.com
Clifford V. Fleener, Visteon Corporation, 3200 East Elm Avenue, Monroe, MI  48162, Tel: 734-243-4859 Email:  cfleener@visteon.com 
David S. Miller, Ford Motor Land Services Corporation, 550 Town Center Drive, Suite 200, Dearborn, MI  48126, Tel: 313-322-3761, Email: dmiller2@ford.com

A manufacturing facility located ¾ miles from the shore of Lake Erie, in southeast Michigan, was the site of 52 acres of sludge impoundments containing electroplating sludge (a listed hazardous waste) and millwater treatment sludge.  Some areas of the impoundments were also filled with foundry sand, slag, and non-sludge wastes.  The site has been used for industrial purposes since 1927.  The site consisted of a number of diked impoundments, underlain by a native clay layer.  Below the clay, a confined water-bearing stratum of limestone/dolomite bedrock exerted uplift pressure on the clay.  In the years since waste placement, the impoundments had become covered by surface water, and native and voluntary vegetation had become established.  The site was home to many species of wildlife, including the American Bald Eagle. High-voltage transmission lines had also been constructed through the center of the impoundment area. 

The waste, which varied in thickness up to 21 feet, had very low strength and would not support the weight of investigative or construction equipment.  The waste constituents of concern were cadmium, copper, lead, nickel, and zinc, which exceeded Michigan’s risk-based criteria for unrestricted land use and for the interface between groundwater and surface water.  Although the sludge was a listed hazardous waste (F006), analytic testing showed it did not exceed regulatory criteria for hazardous waste.  Two of the impoundments were regulated by RCRA interim status regulations; the remainder of the site was covered by CERCLA.   

The site was successfully closed by removing outlying sludge deposits and consolidating them into two discrete containment units, solidifying the sludge, installing a soil-bentonite-fly ash perimeter cutoff wall around each unit, and constructing a composite cover over the solidified sludge.  This paper presents a summary of the challenges involved in designing, permitting, and constructing the in-place closure for the site.

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