Ajit K. Chowdhury, PhD, RMT Inc., 744 Heartland Trail, Madison, WI 53717-1934, Tel: 608-831-4444, Email: ajit.chowdhury@rmtinc.com
Robert Stanforth, PhD, RMT Inc., 744 Heartland Trail, Madison, WI 53717-1934, Tel: 608-831-4444, Email: robert.stanforth@rmtinc.com
Ross Overby, URS Corporation, 500 12^th Street, Suite 200, Oakland, CA 94607-4014, Tel: 510-874-3084, Email: ross_overby@urscorp.com

Arsenic-contaminated soil at a Superfund site in Missouri was treated during 2005 using a ferric sulfate-based additive. Initial testing indicated that 20% Portland cement was needed to treat the soil, in contrast only around 2% of the ferric sulfate additive was required. The exact dosage depended on the arsenic content of the soil. Arsenic screening using X-Ray Fluorescence (XRF) was used for in-field determination of the dose required for each batch of soil. Varying levels of available iron in the soil was an additional factor in selecting the dose of treatment chemical. More than 70,000 tons were successfully treated and disposed, at an average chemical dose of 2%.  The correlation of XRF arsenic data with wet compositional analysis, relationship of available iron to arsenic ratio with TCLP-arsenic analysis, and dosage-response for chemical treatment of soil comparing the bench-scale and full-scale treatment data will be presented.

An Investigation of Arsenic Contamination from CCA-Treated Wood in a Local Playground in Bridgewater, Massachusetts

Cielito DeRamos King, Department of Chemistry, 24 Park Ave, Bridgewater State College, Bridgewater, MA 02325, Tel: 508-531-2115, Fax: 508-531-1785, Email: c2king@bridgew.edu
Michael Grima, Department of Chemistry, 24 Park Ave, Bridgewater State College, Bridgewater, MA 02325, Tel: 508-531-1233, Fax: 508-531-1785, Email: mgrima@bridgew.edu
Eric D. Curry, Department of Chemistry, 24 Park Ave, Bridgewater State College, Bridgewater, MA 02325, Tel: 508-531-1233, Fax: 508-531-1785, Email: edcurry34@hotmail.com

The EPA banned the use of pressure-treated wood containing chromated copper arsenic (CCA) for residential applications on December 31, 2003. However, existing pressure treated wood may contain up to 22 % arsenic, a carcinogen that can seep into the surrounding soil.  The Rainbow’s End playground in Bridgewater, Massachusetts consists of CCA-treated wooden structures such as fences, decks and picnic tables.  It was chosen for this study because it is the largest playground in the town of Bridgewater.  The goal of this study is to quantify the levels of arsenic in the soil at the Rainbow’s End playground and determine if significant leaching of arsenic from the CCA-treated wood is taking place, thus exposing children who use the playground to arsenic in the soil.  A total of 101 playground soil and control samples were collected manually or with a core sampler on two separate dates: fall 2004 and fall 2005.  The test samples were collected at random approximately 5-30 ft from the center of the playground.  The control samples, taken 20 to 30 feet beyond the boundary of the playground, will be used to establish the background level of arsenic in the area.  The samples were analyzed for arsenic levels using a graphite furnace atomic absorption spectrometer following EPA standard method.  Of the 51 test samples analyzed to date, 33 % have arsenic levels above the Massachusetts DEP’s action level of 30 mg/Kg.  In comparison, the 11 control samples have significantly lower levels of arsenic compared to the test samples.  The results of this study will be disseminated to Bridgewater town officials.  

Use of Native Organic-Rich Soil for Passive Removal of Arsenic from Groundwater

P. James Linton, Blasland Bouck and Lee, Inc., 3350 Buschwood Park Drive, Suite 100, Tampa, FL 33618, Tel: 813-933-0697 ext. 19, Fax: 813-932-9514, Email: pjl@bbl-inc.com
Susan Tobin, Task Remediation, Inc., 501 South Boulevard, Tampa, FL 33606, Tel: 813-254-8838, Fax: 813-254-8484, Email: susant@taskenvironmental.com

In 1996, the State of Florida enacted the Lake Apopka Restoration Act to accelerate the restoration of the Lake Apopka Basin through acquisition of agricultural lands impacting the Lake.  One 120-acre parcel in this acquisition was historically used for horticultural purposes that included a muck mining area, structures and disposal areas.  Groundwater in an area associated with historic burn disposal was found to contain dissolved arsenic above State of Florida guidelines; however, sandy soil in this area, both above and below the water table, did not contain significant concentrations of arsenic. 

Studies conducted by the University of Florida (Ma, et al., 1997, 1998 and 1999) have suggested that arsenic has an affinity for soil with a high organic content and reduced pH.  A bench-scale test was conducted to determine if the native organic-rich soil (muck) could be used to passively remove arsenic from the groundwater.  Results for this test were presented to the Florida Department of Environmental Protection, application of the method as the selected remedial alternative was approved, and the remedial action has been implemented at the time of preparation of this abstract. 

The groundwater plume was delineated, the sandy soil within the plume area was excavated, and the excavation was backfilled with native muck soil.  Subsequent groundwater sampling has show a significant reduction in arsenic concentrations in the groundwater with time since treatment.

This poster presents the methodology and results of the bench-scale test, describes remedial implementation, and provides a discussion of effectiveness of the alternative under field conditions.

Arsenic and Fluoride in Drinking Water in Some Parts of Eastern India: a Serious Threat to the Community

Gopal Pathak, Birla Institute of Technology, Bihar, India
S N Singh, UNICEF, Patna, Bihar, India

Arsenic is one of the abundant elements in the Earth’s crust. It is released into the environment through a variety of natural and anthropogenic ways. Arsenic occurs in rocks ,soil , water and air. The principle source of arsenic in the natural environment is arsenic bearing minerals mostly ores containing ores containing sulphide along with Copper, Nickel, Lead, Cobalt and other metals. Similarly, Fluoride is also related to the natural ores present in different forms.

Arsenic contamination in groundwater occurs naturally and released from the soil under conditions conducive to dissociation of arsenic from a solid phase in sediment to liquid phase in water. At present, arsenic contamination is considered to be a dangerous environmental threat and a social health risk, which is well known.

The present paper deals with the analysis of arsenic and fluoride in drinking water in selected parts of Eastern India, which are facing multifaceted problem due to these contaminants affecting the health, social and economic status of the community, especially the poor. Mitigation measures have been discussed in detail.

Sorption and Desorption Behavior of Arsenite, Arsenate and Diphenylarsinic Acid (DPAA) in Soils

Shuzo Tokunaga, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1 Higashi, Tsukuba, Ibaraki 305-8565 Japan, Tel: +81-29-861-9294, Fax: +81-29-861-4561, Email: s.tokunaga@aist.go.jp

Inorganic arsenic compounds have been frequently detected in contaminated sites as well as lead and chromium. Organoarsenic compounds such as diphenylarsinic acid (DPAA) have created new type of soil and groundwater contamination in Japan. Comparative studies were conducted on their sorption and desorption behavior in six different soils [pseudogleyed yellow-brown forest soil (PY), red-yellow soil (RY), yellow-brown forest soil (YB), Kuroboku soil (KS), Kanuma pumice (KP), and thionic gley soil (TG)]. A series of 25 mL of 0.02 mM arsenate [As(III)], 0.2 mM arsenate [As(V)] and 0.02 mM DPAA solutions of different initial pH were prepared and 0.25 g of a soil was added. Sorption of As(III) by every soils was appreciable in the wide pH range 3 to 11. High percentage sorption was obtained for As(V) in the weak acid pH range. Almost 100% As(V) sorption was obtained for soils PY, YB, KS, and TG. DPAA was sorbed by the soils in the acid pH range. The isotherms for sorption of As(III) and As(V) by the six soils were well described by both Freundlich and Langmuir equations. But the isotherms for DPAA sorption by some soils did not fit these models. Yellow-brown forest soil was artificially contaminated by As(III), As(V), or DPAA to prepare model contaminated soils for use in desorption study. The desorption characteristics of arsenic from soil was analyzed in a wide pH range.

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